The cardiothoracic ICU is a 24/7 experience and in many centres (eg. across two US states, as in Krebs et al, 2019) over 50% of patients end up getting extubated between 18:00 and 06:00, which means their post operative management is often left to junior staff. The reason this remains safe and sensible is because the management is so routine that it can be easily protocolised. This chapter handles the "management encompassing resuscitation, initial and ongoing monitoring and supportive treatment" for these carefully selected and apparently indestructable "routine" patients, progressing effortlessly through the science-fiction body horror of cardiac surgery. This is apparently expected knowledge for "Cardiac surgery: including sternotomy for bypass grafting, valve surgery and aortic surgery", a Level 1 topic from Section 2.1.18 in the second edition of the CICM Syllabus for the Second Part Examination; except it has never been asked about historically, probably because much sexier topics necessarily occupy those few and precious pages of exam papers. There are only thirty SAQs, and a million possible syllabus items to test, which means the finite page space should be allocated to those topics where the CICM fellow can really make a difference to morbidity and mortality by their skills and expertise, whereas scenarios where the patients will mostly survive whether the intensivist is present or not are less essential. Still, our presence reduces the rates of renal failure, prevents wasteful overtransfusion and serves an important lubricant function for patient flow, so we should probably know how to do those things.
Day 0 management for the routine cardiac surgical patient
Where does one get this from? No single resource seems to consolidate this information into a single workflow. Engelman et al (2019), the ERAS guideline, is probably the best starting point, but it could not possibly wrap itself around every single minor detail of the process, being mostly concerned with big-picture questions. Still, we do not have a standard pathway established for those finer points, even after approximately seventy years of operating on people's hearts. And it is not as if a fragment of each intensivist's soul becomes embedded in the unique artwork of every management plan; the highly protocolised care is so dependably routine that most cardiothoracic ICUs can be run with minimal medical cover and standing medication orders can be cut-and-pasted from patient to patient with basically no changes to the outcome. Given how ritualised and monotonously repetitive the care processes in the cardiothoracic ICU tend to be, it is baffling that the literature for CTICU does not have a widely accepted alternative to Talley & O' Connor or Harrisons, insofar as they lack for a standard "manual". Each unit, to be sure, have their own The Way We Do Things Around Here, woe betide the junior staff who defy it; but these can vary unpredictably according to local folklore and ancestral wisdom, for which the evidence-based origins may be inscrutably opaque. The following series of observations (let's not call them explanations guides or summaries) are left here for the junior medical staff of these units, particularly those rostered to seemingly endless night shifts, to whom nothing is ever explained.
"Routine" here is an intentionally vague term, because on one hand being cut in half and drained into a bucket is an extraordinary set of circumstances at every level, but also the ICU is the ICU and we have a high threshold for describing something as "unstable" or "deteriorating". The pragmatic objective here is to separate this discussion from the discussion of the "haemodynamically unstable" patient, the hypoxic patient, the bleeding patient, and so on. Of course these people are "unstable" by the definition that they may be dependent on vasoactive agents, ventilated, unconscious, actively receiving fluid resuscitation, and having a rate of blood loss via their drains that would seem considerable in other circumstances, but these are all completely normal behaviours for cardiac surgical post-op humans. Therefore, borrowing from no specific resource, the definition of "routine" will be invented entirely de novo for this section, as "a patient that requires nothing especially creative from the intensivist during their recovery". This is not entirely original, and some of it resembles the work of Flynn et al (2004), describing a fast-track protocol for a high turnover surgical service, where there were specific criteria for consulting the intensivist but otherwise the patients were largely managed by nurses according to standardised guidelines.
The goal is to extubate these patients earlier rather than later. The ERAS Cardiac Society suggests within 6 hours. But if we look a little closer at the evidence behind these recommendations, their basis is ten trials from the early noughties and a metaanalysis by Meade et al (2001) which compiled the data from them all into a conclusion that early extubation seems to safe. It seems safe insofar as the mortality from elective cardiac surgery is low, and it remained low in these trials. The closest thing to an improved patient-centric variable these trials had discovered was a reduction in hospital stay by 1 day. The duration of ventilation was reduced by a mean of seven hours, which does not seem like enough time to develop any of the known complications of mechanical ventilation, or to become picked in enough sedatives to develop delirium, or to miss out on enough mobility to become weakened and debilitated. Of course, nobody who has ever been awake and intubated will complain about being extubated seven hours earlier, but the discomfort and inconvenience do not seem to translate into morbidity outcomes. Only Rajakaruna et al (2005) found some data to support the assertion that "longer hospitalization, higher morbidity, mortality, and increased costs" are related to delayed extubation, but this study picked, from among over 7,000 cases, the 2.6% who remained intubated for four days or longer. Obviously this cohort was nothing like the "routine" group we agreed to discuss here (for one, 31.9% of them had NYHA Grade IV symptoms before going to surgery).
The remaining genuine arguments for rapid extubation are, therefore, fundamentally economic. On the other hand, why would you keep them intubated? If the surgery started late, ran late, and finished late, the night staff who receive the patient have no appetite for airway shenanigans and will usually default to making their shift as quiet and uneventful as possible; buit that shift was always going to be quiet and uneventful. Krebs et al (2019) noted that in a retrospective series of 20,758 patients the 52.1% who were extubated overnight had the same low rate of reintubation as the daytime cohort (3% or so). In short, it does not seem to matter whether or not you extubate them early or late, and if they end up ventilated for longer than usual, it usually has nothing to do with some kind of conscious choice on the part of the medical team, and more to do with the overall poor quality of the protoplasm.
When one has only met the patient for the first time, they are still some hours from extubation, and likely full of opioids and sedatives, to the effect that they will not have anything valuable to contribute to managing their own respiratory function
Mode: SIMV. "Oxygen consumption was 28 per cent above the predicted normal value of 208 ml. per minute with the respirator and increased to +126 per cent when breathing spontaneously", complained Thung et al in the early days of cardiac surgery (1963). "These data lend objective support for the prophylactic use of respiratory assistance in patients after cardiac surgery" they concluded, suggesting that the question of whether or not to ventilate them was up for debate. Increased CO2 production due to the post-CPB inflammatory response and decreased lung compliance due to effusion/collapse/pulmonary oedema are definitely present in a majority, increasing the effort of breathing just at the exact time that the myocardium is at its weakest and the patient's pain is at its greatest. Therefore a mandatory mode should be the standard post-op, with a transition to a spontaneous mode as soon as the patient is awake enough to make breathing efforts.
Volume: lung-protective. The harm done by injurious tidal volumes is unlikely to be affecting many patients in the CTICU considering the duration of mandatory ventilation for this group should be relatively short, and there will not be enough time to do any real harm. Still, Romagnoli & Ricci (2015) and Zochios et al (2018) recommend we keep to lung-protective volumes, even though all of the trials in this space were "neither large enough to be convincing nor powered for clinically meaningful primary outcomes", i.e. there is probably no reason to kick them in the lung with every breath just because ANZICS CTG haven't yet burned a truckfull of grant money to answer this question.
PEEP: lowish. Knowing what the Day 1 X-ray usually looks like, one might be tempted to crank up the PEEP, but this may be misguided. You usually don’t need much PEEP, because the patient may be hypovolemic, and because the lung is still healthy (i.e. not having post-pump ARDS right now). That collapsed left base is likely to be resistant to PEEP anyway, and would probably require recruitment manoeuvres to open. If that is what one wishes to do, Padovani & Cavenaghi (2011) reported that even pressures up to 40 cmH2O are well tolerated as short recruitment manoeuvres (in the sense that there was only a 12% incidence of hypotension) and Hu et al (2022) followed by confirming that these are usually not complicated by pneumothorax.
There being little real data to guide the decisions here beyond the pragmatic need to be similar to successful peers in your practice, one could look at the experience of high-volume centres in Italy (Bignami et al, 2019), who use 2-5 PEEP, or at the retrospective data by Chi et al (2024), who used a PEEP of at least 7. A small RCT from Iran (n=180) also demonstrated some positive outcomes from PEEP at 8 and 10, but this is to be taken with a grain of salt, as length of ICU stay and duration of ventilation are often determined by matters other than just hypoxia (eg. ICU overnight staffing).
Moreover, it is possible that we are just overthinking this. Magnusson et al (1997) and Tenling et al (1998) agreed that hypoxia due to atelectasis is one of the commonest respiratory complications following cardiac surgery, but Tanner & Colvin (2020) did not find any data that could attribute any real patient-centric outcomes to this finding, and if it was causing some kind of tangible harm we would surely have identified this after decades of operating (considering that there are 1.0-1.5 million cardiac surgeries happening each year and 30-72% of the patients develop radiological evidence of atelectasis). On that basis, it could be possible to conclude that PEEP is a fairly unimportant choice, and that the decision could be left to the anaesthetist, bedside nurse, janitor, or whatever settings happen to be the ventilator defaults.
FiO2: aim for normoxic oxygenation targets. We know (or at least strongly suspect) that hyperoxia does harm wherever something is getting reperfused (hello stroke, cardiac arrest, TBI), so it stands to reason that oxidative stress should also create problems for post-op cardiac surgical patients. True, they clearly experience it (Lopez et al, 2024), but so far investigators have not been able to marry to an increased rate of complications, though many have tried. On the other hand, Sutton et al (2014) extracted the entire cohort of cardiac surgical patients from the Australian ANZICS APD database and found that the hypoxic ones (PaO2 < 60 mmmHg) were also the ones with greater risk of death (the difference was 1%, or 1.3% vs 2.3%). Because the outcome effects of oxygenation targets in mechanically ventilated adults remain a vaguely U-shaped field, "normal" seems to be the safe default setting, which might mean something like sats of 94-96%.
High oxygen requirements are not an expected feature of cardiac surgery and falls out of the "routine" definition. How high is too high? As often seems to be the case, there is not consensus for this, and we are each left to make our own definition, or to grab another one that happens to be laying around. For example, Wang et al (2022) defined it as a PaO2/FiO2 ratio of less than 100, similarly to how severe ARDS is defined, but this seems like an extremely high bar, considering that one can achieve such a ratio at an FiO2 of 50% with sats of 85% (PaO2 50mmHg). The incidence of hypoxia at this level of severity was 4.2% for the investigators. Ji et al (2008) defined it as FiO2 > 45%, Yahagi et al (1997) used a P/F ratio of 150, and the author tends to regard anything that requires high flow nasal oxygen as "severe" because it delays the discharge from ICU in his institution, which is a pragmatic cutoff at a P/F ratio of approximately 150-175 (i.e. being able to achieve nothing better than sats of 92% on 40% FiO2). All patients performing as poorly as this require special weapons and tactics, discussed in the hypoxia chapter.
The failure of the critical care community to find major differences in outcome for any deviation from the MAP-of-65 centrality among most populations of critically ill patients should leave the reader unsuprirsed to learn that among cardiac surgical patients there is also no evidence-based consensus. Experts, when cornered in boardrooms and pressured to generate guidelines, tend to seek the safety of normal values. The S3 German guidelines (2018) are a good example of this, and here are their Empfehlungen:
Or, if you want to get weird with invasive haemodynamic monitors,
For most scenarios observed in the trainee's period of dependence, i.e. for the sort of patients they will be allowed to watch over without constant supervision, the most fussed-over variable will be the MAP, followed potentially by the CVP. It is safe to say that a large minority of trainees may not have the luxury of obsessing about the other parameters, as the penetrance of PA catheter use across the ICUs of Australia is hugely variable, ranging from 4.7% in QLD and 7.8% in SA to to 72% in Victoria and 57.9% in NSW (i.e. 66% of CICM trainees have routine access to these and 34% do not).
So. Returning to the matter of the MAP. Whereas the conventional teaching in the rest of intensive care is to aim for a MAP > 65, the question of what the MAP needs are for a cardiac surgical patient is strangely open, with eminent authors throwing numbers around without offering any solid reference in support. As an example, André & DelRossi (2005) suggest a MAP of 70-80, and Stephens & Whitman (2015) suggest a target MAP range of 60-90, or SBP 90-140, but their reference for this is the André & DelRossi paper, which is frankly baffling. The impression one quickly develops is that this is all entirely eminence-based, and that the correct goal is the random number generated by the most senior person in the room at the time of the question. Searching for ever greater eminence leads the reader to surgical textbooks, among which there is no higher recommendation than the RACS reading list for cardiothoracic surgery. Of these, each give a different target, and none give any references whatsoever:
That's not helpful. The basic principles for how to decide the blood pressure goals in these patients are thankfully pretty generic:
You do not want the blood pressure too low. The drop in blood pressure that follows rewarming, as well as the transition of care from the anaesthetic team to the ICU (as undisclosed doses of vasoactrive agent boluses wear off in the course of corridor transit) is so common that it has been referred to as "anaesthesia drop-off syndrome". It is unlikely to go unnoticed, as the attention on the patient is maximal during this early period. Unsuprisingly, it seems to have little effect on outcomes, most likely because it is rapidly and effectively corrected. Sustained low blood pressure is bad mostly because of the diastolic component, as this is what perfuses the coronaries, and in particular the grafts which may be experiencing some kind of vasospasm.
You do not want the pressure too high. Sure, the coronary grafts will probably not "blow", but all guideline writers seem to have the belief that bleeding complications are more likely (especially from the aortic cannulation site). Additionally, high afterload will lower the cardiac output, increase subendocardial pressure, and so lower cardiac perfusion, worsen the mitral regurgitation, etc etc. The reader interested in the causes and a discussion of the reasoning behind the management options can be redirected to the chapter on hypertension following cardiac surgery.
A high CVP is also undesirable. Let alone the possibility that this is cardiac tamponade or some other cause of obstructive shock, a raised CVP puts pressure on right-sided structures (and the sutures holding those structures together), and increases the leak from small cauterised venules. The specific acceptable value for CVP is even more difficult to track down, and all searches mostly point to 8-12 as the target range, but again with little evidence to support them.
So, what to do with the circulatory system? The conventional answer, in this evidence-free wasteland strewn with opinion, is to do it The Way We Do Things Around Here. Ramanan et al (2021) assessed Australian practice to see what everyone's approach was, and determined that basically everyone (except for 11% of weird outliers) used MAP as the target for their first fluid boluses and vasopressors, and the MAP target was 65-70 mmHg for 66% of the surveyed responders (with 17% targeting a MAP of >70 and 23% targeting 60-64). Aronson et al (2017), surveying American practice, did not ask specific MAP targets, but did establish that the blood pressure was the main thing his US colleagues were looking at when deciding on whether to give fluids or pressors.
Leaning heavily on the chapters about hypertension, fluid management, inotropes and vasopressor selection to fill in much of the detail, the following broad brushstrokes can be painted for the general trends in the haemodynamic management of a routine cardiac post op:
They have several huge drains. There is blood coming out. This is normal, and in fact, good (in the sense that ongoing drainage suggest patency). What, then, would be concerning, as far as normal and abnormal drain behaviour goes? Objectively:
The actual numeric amount of drainage depends as much on the surgeon as on anything we do medically, and is clearly a modifiable factor, as an Australian study by Bhaskar et al (2010) found that elective Jehovah's Witnesses experienced almost 50% less drain blood loss than those counterparts who agreed to receive transfusions. ERAS recommend removing them when the output becomes clearly serous, but realistically this may take a while and the longer you leave them, the more they will drain. But enough about this: deviation in the direction of large drain volumes puts this scenario firmly in the bleeding complications following cardiac surgery chapter.
"Drainology" seems to be the official ERAS term for the art of carefully maintaining these tubes. There are even evidence grades associated with their recommendations, which is hilarious, because the recommendations, fundamentally, are:
Where by "weird stuff", ERAS mean:
This, of course, flies in the face of all observed medical and nursing bedside behaviour in cardiothoracic units worldwide, where the abovementioned manoeuvres are often performed as a means of preventing cardiac tamponade and resternotomy. Chest drains clog: Karimov et al (2013) found that about a third were blocked with clot at the time of removal, and of these, the majority (86%) were blocked below the level of the skin, where an inspection of the tube exterior will not reveal this fact to the observer. Aside from the fact that only 150ml or so of clot is enough to produce clinically significant tamponade, the presence of retained blood is unpleasant in a whole series of other important ways, most notably local and systemic inflammation, atrial fibrillation, effusion, and fibrosis. These facts practically beg you to do whatever is necessary to remove clots from the drain.
"Milking" the drains refers to various nonspecific manipulation like twisting, tapping or lining the drain tubing to agitate the contents and dislodge any loose clots that may be obstructing drainage. "Stripping" refers to the well described practice of occluding the drain upstream, running an occlusion (be it strong fingers or something more stiff like the blunt edge of scissors) along the elastic chest drain tubing (not the PVC drain itself) to create a vacuum in the drain, and then releasing the upstream occlusion. The result is a transient increase in the suction applied to the drain, which could be enough to dislodge a blocking clot.
Does any of this really work? The results of published experiments are varied, as probably are the surgical and nursing techniques in the studies that test them. There is, however, some potential for harm. Halm (2007) quotes an ancient experiment by Duncan & Erickson (1982) where intrathoracic pressures were measured at different stripped tube lengths, and the results sound horrific: with even only 15cm of tubing being stripped, the vacuum generated was something like -87 cmH2O, increasing to -400 cmH2O when the entire 135-cm length of the tube was involved.
That's obviously not nothing, considering that usually the pressure on the suction drain is -20 cm H2O. Surely, one must conclude, it must be unsafe to suction those things at -400 cmH2O. However, the evidence for harm is really not available. Duncan & Erickson is the same ancient paper quoted by all subsequent authors as a warning that as little as 15cm H2O negative pressure is enough to produce the entrapment of tissue in the eyelets of the drains, resulting in trauma and potentially worsening the bleeding; but no other data is ever mentioned. It is therefore remarkable that the subsequent forty years of cardiac surgery have not produced more evidence in support of this, considering how common the practice. That we do not see chunks of pericardium in the drain more often is a sign, perhaps, that the mediastinal tissues are made of reasonably stern stuff.
So, they are proper blocked. At what stage do you panic, or crack open the sterile seal on the connection to the tubing and try to go up there with a Y-sucker? Boyacıoğlu et al (2014), rather proud that they have discovered a novel use for the Fogarty catheter, seems to be the only paper on the technique of aspirating or otherwise mechanically clearing these catheters by opening them to air and suctioning them manually. They prepared and draped the mediastinal drain to prevent infectious complications, and reported no adverse events, but this did not stop ERAS from asking them to please stop doing that. The possibility that a deep sternal wound infection would develop from the introduction of a sterile catheter into another sterile catheter is not zero, even if the operator was fully scrubbed, but the risk is possibly lower because the drains only remain in place for a short period of time, and because the movement of material in these tubes is rather brisk and unidirectional, i.e. moving material out rather than in.
In discussing this aspect of drain management, we do need to pivot from the discussion of drain behaviour to the discussion of human behaviour, as they can't exactly pull themselves out. The ERAS recommendation that the drains be considered for removal as soon as the output becomes serous is as vague as the definition of what "serous" is, and most publications on this matter are either equally noncommittal or committed to a large range of contradictory recommendations. The timing of removal or output criteria seem to vary from surgeon to surgeon, such that many otherwise highly scientific institutions with distinct rationale for virtually everything else in their practice will still have a "Dr So-and-so's Protocol" to describe the idiosyncratic drain management approach of each surgeon. Taylor et al (2018), in a survey of paediatric cardiac surgical centres, found that the drain output criteria varied from 1mk/kg/hr to 9ml/kg/hr.
Why would you keep them in for longer? Retained blood in the chest is undesirable, as is mentioned above, and theoretically having the drains in for a little longer may clear a little more of it. Andreasen et al (2016), looking at drain removal on the day of surgery, found an increase in the rate of effusions requiring intervention (an increase from 13% to 20%). El-Akkawi et al (2024) did an RCT to explore this question again and found no difference between the early and late group, but their patients overall had a much higher rate of late pleural drainage (30%) which casts some doubts on the generalisability of their data. A valiant effort to systematically review the contemporary data by Heydari et al (2021) yielded nothing groundbreaking (five cohort studies) and offered a fairly conservative compromise as a solution (pull them out on Day 1 if the output is less than 100 ml in 8 hours).
The bottom line is that sedation is required to tolerate or forget the unpleasantness of sternotomy and graft harvesting, and once these are behind us, it is no longer necessary to be sedated. There are also other motives for weaning sedation:
The latter is perhaps not as important, as the amount of sedative drugs absorbed by the routine cardiac surgical patient over the short period of ventilation is unlikely to be so great that some sort of serious neurotoxicity is likely to occur. Liu et al (2017) attempted to derive some cardiospecific guidance from the generic sedation guidelines (and since then, we have also had the 2021 KSCCM guidelines and the 2018 SCCM guidelines, as well as Hughes (2020) for perioperative patients) but none of these have anything special to say about the cardiac surgical population. Hu et al (2024), looking at 18 RCTS (1652 patients) were compelled to make an argument in favour of dexmedetomidine and ketamine (of all things), but on the basis of only two trials with a total = n=110, from Egypt and Pakistan. All one can do in response to this sort of thing is apply the common rules which should be similar for all:
The keyword one will need to spout in the exam is "multimodal analgesia". The use of something other than opioids seems to be the clear winner on the basis of many data points. The usual approach is not to add one thing, but rather to integrate a bundle of various pain management strategies. Li et al (2018) and Rafiq et al (2014) developed two such protocols (one with paravertebral blocks, the other with ketorolac, gabapentin, dexamethasone ibuprofen and magnesium).
The use of ketorolac in Rafiq et al may puzzle some readers, as the use of NSAIDs (especially strong COX2 inhibitors) in cardiac surgical patients is anecdotally frowned upon owing to their combination of antiplatelet and prothrombotic effects. There are both pros and cons to this, of course, and this perception could be shifting. Abou-Arab et al (2024) reported that only 10% of surveyed anaesthetists claimed to "never" use NSAIDs in cardiac surgical patients, and Huette et al (2024) were able to scrounge up enough equipoise to pass a randomised trial through ethics. Grant et al (2023) in the ERAS statement on pain relief after cardiac surgery did not commit to actually giving these drugs a recommendation (instead pointing out that they are controversial). That might sound like damning with faint praise, but is in fact a move towards NSAIDS, as previously they might have been banned altogether, considering findings like Nussmeier et al (2005) where parecoxib quadrupled the risk of stroke MI and PE after CABG (2.0 percent vs. 0.5 percent).
Yes, electrolytes become abnormal following cardiopulmonary bypass:
Yes, you should replace them. No, there is no evidence to support this, but you should do it anyway.
A widely held belief among cardiothoracic ICU staff is that with enough attentive electrolyte correction one may be able to prevent AF, but this belief has its foundations in ancestral folk tales and sympathetic magic. Challenging this elder lore tends to reveal these practices as fantasy; at least in terms of AF prevention (because fibrillators will fibrillate, irrespective of what you do with them). For example, Lancaster et al (2016) found no strong association between potassium replacement and AF, whereas magnesium replacement actually increased the rates of AF. Unhelpfully, none of the guidelines even mention any of this. The 2019 ERAS guidelines and the European EACTS guidelines for perioperative medication (Sousa-Uva et al, 2018) stay mostly in their surgical lane and do not make any electrolyte-related recommendations at all. The cardiopulmonary bypass interdisciplinary guidelines also only mention magnesium, as a "can be considered" intraoperative intervention to prevent post-op arrhythmias (Wahba et al, 2025) which is not exactly applicable to the experience of the night resident in the CTICU.
But what if you were a believer and wanted to quote some data to support your obsession with normal electrolyte values? Polderman & Girbes (2004) is probably the most cited paper to support the widespread prophylactic use of electrolyte replacement. The authors measured blood and urine electrolytes and found differences that ranged from concerning (phosphate levels of 0.43 on average) to trivial (potassium difference from 3.9 to 3.6 mmol/L), to which they attributed a change in the observed antiarrhythmic agent requirements. 38% of patients in the hypo-electrolytaemia group had required something like amiodarone or sotalol, whereas only 10% of the control group needed these, and so "it seems highly likely that electrolyte disorders in our patients either caused these arrhythmias or contributed to their development", the authors concluded. Miller et al (2005) then went on to review 20 RCTs (all available since 1966) and scrounged up 2490 patient data sets with enough confidence to claim that magnesium replacement reduced the rate of AF from 28% to 18%. These patients were not necessarily depleted, mind you; they were receiving (vs not receiving) magnesium replacement prospectively.
So the specific ranges of electrolytes often quoted in local cardiac surgical guidelines (keep potassium in the 4.0-4.5 mmol/L range, keep magnesium around 1.0 mmol) do not seem to be grounded in anything more scientific than the observation that electrolyte derangement seems to be associated with some kind of nonspecific cardiac badness. That might seem like some kind of unscientific parochialism, but this impression only develops if one observes the practice of electrolyte correction through the impossibly narrow telescope of clinical trials and society guidelines. In fairness, extremes of electrolyte derangement do indeed produce bad outcomes, and so if we accept that the risk of arrhythmia does not abruptly start at a K+ of 8.0 or 1.0 mmol/L, then we must logically also accept that there is a U-shaped continuum of increasing risk in both directions, rising from some ill-defined risk nadir in the middle, and that nadir probably represents the normal healthy adult values. Considering that electrolyte replacement is a cheap safe and uncontroversial practice, the cost of de-adoption could be greater than the cost of continued use. If one $7,000 night of ICU stay is prevented by 40 mmol of potassium chloride, at $10 per 10mmol, it would pay for 175 patients worth of replacement; i.e. one would literally only need to prevent four cases of AF to justify the cost of potassium correction in a relatively busy Australian cardiothoracic ICU.
So why does it happen? Brinsfield et al (1964), in an early attempt to understand the experience of the first patients exposed to the still-early versions of this technology, exposed dogs to twelve hours of godawful steampunk bypass and speculated on the meaning of the changes they observed:
"Increased aldosterone excretion could be stimulated through left atrial volume receptors as the amount of the pulmonary flow diminishes, resulting in enhancement of tubular reabsorption of sodium and water, and increased urinary potassium excretion... ...Concomitantly increased antidiuretic hormone production could account for increased plasma osmolarity and isosthenuria; whereas increased potassium levels would be ascribed both to traumatic hemolysis and to ionic shifts associated with local hypoxia."
In contrast, modern human patients do not tend to have the same experience, as modern circuits do not tend to grind their red cells quite as much, which means most patients experience potassium magnesium and phosphate depletion. Polderman & Girbes (2004) suggested that urinary excretion was the main culprit, and proposed that this must be come kind of tubular dysfunction (as it could not possibly be the activity of some regulatory mechanism, as it was happening in the face of falling electrolyte levels).
To draw a distinct line between the routine and non-routine patient, this section refers to the patient who is not bleeding to the point where one would wish to discuss them in the next M&M meeting. Some coagulopathy following cardiopulmonary bypass is fairly normal, because:
It is therefore routine to test coagulation after return from theatre for these patients. That much is an accepted norm for every setting; but what one then does with the findings is curiously individual and rudderless. What is too much, which metric do you use, and when do you give more protamine or products as a top-up? The 2024 EACTS/EACTAIC/EBCP Guidelines do not suggest any specific management strategy. Indeed, how could they - the measurement of ACT varies from machine to machine, and is not correlated neither between manufacturers nor even between two devices made by the same manufacturer, making a mockery of any purposeful standard-setting or attempt to establish normal value ranges. To say nothing of TEG and ROTEM, whose manufacturers produce two near-identical device technologies that refuse to standardise nomenclature and reporting methodology for what appears to be entirely commercial reasons, as multiple agents compete for the growing point-of-care coagulation testing market. The practical utility of "formal" coags is of course dismissed entirely, as the events play out over minutes, and "proper" laboratory tests may take hours.
What, then, does the poor night resident do with the results of any of these tests, when confronted with the confusing appearance of a cardiac surgical patient who is not hosing blood out of the drains, but is merely oozing quietly with some borderline drain output measurements? Well:
| Variable | At ICU admission | 24 hrs post op |
| APTT | 39 | 34 |
| INR | 1.4 | 1.2 |
| Fibrinogen | 2.15 | 3.0 |
| Platelets | 29% decrease (to ~150) | back to normal (~200) |
(from Čeke et al, 2014, Gielen et al 2016 and Ikić, 2021). In summary, the values renormalise within the first 24 hours without correction: the inflammatory post-operative state tends to lead to an increased production of clotting factors and they are replenished rapidly unless they are still being consumed. These ballpark figures should give some confidence to the person who is questioning themselves while looking at vaguely abnormal coags and a vaguely abnormal hourly drain output.
One typically allows the patient to re-warm spontaneously. Rarely is any extraordinary heating required. However the patient is returning to ICU from an environment where their temperature is a secondary concern, after the comfort of the surgeon, and moreover some of them were recently cooled to the point of intentional circulatory arrest, which has residual temperature consequences. Most CABG surgery usually happens with only mild hypothermia (approximately 34°C), but occasionally one needs to go as low as 18-20°C.
The effects of hypothermia are discussed elsewhere, but we could list the ones that have a special significance for cardiac surgical patients:
Coagulopathy and platelet dysfunction
Decreased cardiac output and bradycardia
QT prolongation and the J wave
Arrhythmias - classically AF and VF
Resistance to defibrillation
Vasoconstriction and increased LV afterload
"Cold diuresis" due to decreased vasopressin synthesis
Shivering
Confusion and decreased level of consciousness
In summary, perioperative hypothermia is to be avoided, and nurse-initiated warming blanket therapy is welcomed - Bezerra et al (2021) even demonstrated this with a clinical trial, though honestly, any transfer of autonomy to cardiothoracic surgical nurses should be viewed not as some act of generosity but as a desirable and natural distribution of responsibility away from the cognitively overloaded medical staff. Haji-Jafari et al (2023) confirmed that the practice of actively rewarming these people not only does not cause haemodynamic instability, but actually brings them closer to stability faster, and seems to reduce the rate of complications. If one needs a specific number to aim for, it would be a core temperature of 37.0-37.5°C, which is roughly in line with human normothermia (whatever that is).
There are several common tropes for the post op cardiac surgical patient, which are alarming enough for the nurses to alert a locally present junior doctor, but not enough for them to awaken the sleeping intensive care specialist, or to divert the patient off the Routine Cardiac Post Op Railroad tracks. These can be broadly summarised as:
To come to the conclusion that the patient falls into this "otherwise totally normal" category, one would have to actually get up and assess them, thereby assuring themselves and the bedside staff that the patient is not otherwise deviating from the routine pathway. The specific reassurances one looks for would include:
With these caveats, one may begin to regard the result as a curiosity, if not exactly spurious. There are multiple possible reasons for a raised lactate in the cardiac surgical patient, and only some of these are concerning. It is also valuable to conceptualise this as two distinct phenomena, one early and one of late onset. Early lactate elevations are usually something to do with what happened in theatre, and represent reperfusion and tissue hypoxia, which suggests that they should be regarded more seriously - and indeed admission lactate values of > 3.0 mmol/L were associated with about ten times greater mortality than < 3.0 mmol/L, in Maillet et al (2003). Late lactate elevations (>6 hrs after ICU admission) are less concerning, specifically when the rest of the patient looks reasonably good, and are often described as "a benign, self-limiting condition" that resolves over the first 24 hours. When nothing else seems wrong, it is variably attributed to catecholamine excess, accelerated glycolysis, sluggish clearance by an uncooperative liver, or sluggish washout from a leg with ligated veins.
The finding of temperature "rebounding" into fever following rewarming is a common finding among cardiac surgical patients, and is usually attributable to the tissue injury and the contact between the blood and the extracorporeal bypass circuit. O’Mara (2017) quoted the incidence of this as something between 30% and 100%. It appears to peak around day 1 post op, and it does not seem to identify patients who will subsequently go on to have positive cultures. The same can be said for the inflammatory markers: WCC and CRP are inevitably elevated in these people - Santonocito et al (2022) found that CRP rises a little bit faster and is on average around 120-140 by day 1 - and the values are wildly variable, such that one cannot identify an infectious cause of a raised CRP with any degree of precision.
That is not to say that post-op or perio-operative infection is entirely impossible; only that it is sufficiently uncommon (especially where an early fever is observed) that most of the cultures you send in this time period will be normal. The overall rate for surgical site infection is something like 0.5% to 7.8% (depending on how you define it), and the kinds of patients who will go on to develop this are fairly predictable. According to Zukowska & Zukowski (2022), they are old, diabetic, obese or malnourished, smokers, and those who underwent emergency surgery. Wang et al (2021) also noted the risks for post-op pneumonia (the most common infectious complication of cardiac surgery), which were blood transfusion, renal failure, prolonged bypass time, and a re-do operation (in order of risk), with pneumonia developing in about 10% of patients. Being ventilated for a prolonged period is probably the most significant risk factor: after 48 hrs invasive ventilation, Hortal et al (2009) found the risk of VAP increases to almost 50%.
So, to be fair, it would be reasonable to overreact to a late post-operative fever in cardiothoracic ICU, because the low incidence of infectious complications should not be dismissed as insignificant. For Wang et al, the mortality in the pneumonia cohort was around 26%, which is over three times higher than the mortality for HAP in other patients (~7-8%). The main reason for this is likely the poor tolerance of secretions, and the difficulty in clearing them when one's chest wall is still healing from surgery. With the added insult of perioperative effusions and atelectasis, these patients have respiratory disadvantages to exacerbate respiratory failure, and present several confounding radiological features which could obscure the presence of pneumonia. These factors tend to decrease the threshold for starting antibiotics in this population, particularly where the surgery involved the implantation of a valve or pacemaker.
Without revisiting huge locally available digressions on thermoregulatory mechanisms and the management of shivering, it would be reasonable to summarise why shivering is bad in the cardiothoracic ICU, when you are recovering from a routine operation:
So, in summary, this completely normal human reaction is totally obstructive and inappropriate, and needs to be managed with harsh chemicals. Again, there is a robust discussion of these elsewhere, and only a list of the strategies should be listed below, in order from most benign to most aggressive.
And this undesirable excess of movement brings us neatly to the discussion of:
To half-awaken and immediately become enraged by the ongoing process of mechanical ventilation is an entirely normal intubated human behaviour following cardiac surgery, according to a study of the Australian humans by Heily et al (2024). Half of these people emerged from sedation with a RASS of at least +2, and of course soaked up a lot more sedation, as well as vasoactive agents and nursing attention. Gardner et al (2005), interviewing patients following their recovery, established to nobody's surprise that their recollections of immediate post-operative events were largely negative, and focused on the endotracheal tube ("the worst part was whilst I still had the tube down my throat", said 85 year old Thomas). Which, logically, lends itself to the question; if the tube is the biggest problem, why not extubate them?
As mentioned in the first paragraphs of this chapter, one would extubate these patients early, under virtually all circumstances, except apparently between the hours of midnight and six. ERAS recommends a benchmark of early extubation (<6 hrs), and there is no data to suggest that extubation in the moonlight is somehow inferior. Even in the ancient days of aggressive surgical recovery protocols, RCTs of this strategy could not find any trend towards worsening morbidity. A more recent work by Gershengorn et al (2019) observed the outcomes of 142,225 elective CABG patients, of whom over 40% had overnight extubation, and who were none the worse for it (the reintubation rate changed from 2.2% to 1.7%). Krebs et al (2019) looked at a much smaller cohort (a mere 41, 993) and came to much the same conclusions. In short, the time of the day should not matter, and the reasons for keeping patients intubated until closer to the morning has more to do with preference than risk.
Wahba, Alexander, et al. "2024 EACTS/EACTAIC/EBCP Guidelines on cardiopulmonary bypass in adult cardiac surgery." Interdiscip CardioVasc Thorac Surg 2025; doi:10.1093/icvts/ivaf002.
Engelman, Daniel T., et al. "Guidelines for perioperative care in cardiac surgery: enhanced recovery after surgery society recommendations." JAMA surgery 154.8 (2019): 755-766.
Flynn, M., et al. "Fast-tracking revisited: routine cardiac surgical patients need minimal intensive care." European journal of cardio-thoracic surgery 25.1 (2004): 116-122.
Lee, Lawrence S., et al. "The presence of a dedicated cardiac surgical intensive care service impacts clinical outcomes in adult cardiac surgery patients." Journal of Cardiac Surgery 35.4 (2020): 787-793.
Johnson, Lauren A., et al. "A closed surgical intensive care unit organization improves cardiac surgical patient outcomes." Journal of Thoracic Disease 16.2 (2024): 1262.
Lim, Ju Yong, et al. "Influence of a high-intensity staffing model in a cardiac surgery intensive care unit on postoperative clinical outcomes." The Journal of thoracic and cardiovascular surgery 159.4 (2020): 1382-1389.
Katz, Jason N., et al. "Length of stay, mortality, cost, and perceptions of care associated with transition from an open to closed staffing model in the cardiac intensive care unit." Critical Pathways in Cardiology 16.2 (2017): 62-70.
Lamarche, Yoan, et al. "A survey of standardized management protocols after coronary artery bypass grafting surgery in Canadian intensive care units." Canadian Journal of Cardiology 27.6 (2011): 705-710.
Airway and extubation
Flynn, M., et al. "Fast-tracking revisited: routine cardiac surgical patients need minimal intensive care." European journal of cardio-thoracic surgery 25.1 (2004): 116-122.
Meade, Maureen O., et al. "Trials comparing early vs late extubation following cardiovascular surgery." Chest 120.6 (2001): 445S-453S.
Rajakaruna, C., et al. "Risk factors for and economic implications of prolonged ventilation after cardiac surgery." The Journal of thoracic and cardiovascular surgery 130.5 (2005): 1270-1277.
McCarthy, Ciana, and Nick Fletcher. "Early extubation in enhanced recovery from cardiac surgery." Critical Care Clinics 36.4 (2020): 663-674.
Hosseinian, Leila, and David L. Reich. "Commentary: What makes a cardiac surgical intensive care unit safe after midnight?." The Journal of Thoracic and Cardiovascular Surgery 157.4 (2019): 1543-1544.
Krebs, Elizabeth D., et al. "Is routine extubation overnight safe in cardiac surgery patients?." The Journal of thoracic and cardiovascular surgery 157.4 (2019): 1533-1542.
Ventilation
THUNG, NALDA, et al. "The cost of respiratory effort in postoperative cardiac patients." Circulation 28.4 (1963): 552-559.
Padovani, Cauê, and Odete Mauad Cavenaghi. "Alveolar recruitment in patients in the immediate postoperative period of cardiac surgery." Brazilian Journal of Cardiovascular Surgery 26 (2011): 116-121.
Mellroy, Cournand. "The Cost of Respiratory Effort in Postoperative Cardiac Patients." Circulation 28 (1965).
Mathis, Michael R., et al. "Intraoperative mechanical ventilation and postoperative pulmonary complications following cardiac surgery." Anesthesiology 131.5 (2019): 1046.
Bignami, Elena, et al. "Routine practice in mechanical ventilation in cardiac surgery in Italy." Journal of Thoracic Disease 11.4 (2019): 1571.
Chi, Yi, et al. "Maintaining moderate versus lower PEEP after cardiac surgery: a propensity-scored matched analysis." BMC anesthesiology 24.1 (2024): 55.
Hu, Ming-Chi, et al. "Recruitment maneuvers to reduce pulmonary atelectasis after cardiac surgery: A meta-analysis of randomized trials." The Journal of thoracic and cardiovascular surgery 164.1 (2022): 171-181.
Setak-Berenjestanaki, Mostafa, et al. "The prophylactic effect of different levels of positive endexpiratory pressure on the incidence rate of atelectasis after cardiac surgery: a randomized controlled trial." Medical Journal of the Islamic Republic of Iran 32 (2018): 20.
Magnusson, Lennart, et al. "Atelectasis is a major cause of hypoxemia and shunt after cardiopulmonary bypass." Anesthesiology 87.5 (1997): 1153-1163.
Tenling, Arne, et al. "Atelectasis and gas exchange after cardiac surgery." Anesthesiology 89.2 (1998): 371-378.
Tanner, Tristan George, and Mai O. Colvin. "Pulmonary complications of cardiac surgery." Lung 198.6 (2020): 889-896.
Romagnoli, Stefano, and Zaccaria Ricci. "Lung protective ventilation in Cardiac Surgery." Heart, lung and vessels 7.1 (2015): 5.
Zochios, Vasileios, Andrew A. Klein, and Fang Gao. "Protective invasive ventilation in cardiac surgery: a systematic review with a focus on acute lung injury in adult cardiac surgical patients." Journal of cardiothoracic and vascular anesthesia 32.4 (2018): 1922-1936.
Sutton, A. D. J., et al. "The association between early arterial oxygenation and mortality post cardiac surgery." Anaesthesia and intensive care 42.6 (2014): 730-735.
Lopez, Marcos G., et al. "Intraoperative oxygen treatment, oxidative stress, and organ injury following cardiac surgery: a randomized clinical trial." JAMA surgery 159.10 (2024): 1106-1116.
Begashvili, Ioseb, Merab Kiladze, and C. Grigolia. "Oxygen in cardiac surgery: does more mean better?." Translational & Clinical Medicine-Georgian Medical Journal 9.1 (2024).
Circulatory endpoints
Fremes, S. E., et al. "Effects of postoperative hypertension and its treatment." The Journal of thoracic and cardiovascular surgery 86.1 (1983): 47.
Carl, M., et al. "S3 guidelines for intensive care in cardiac surgery patients: hemodynamic monitoring and cardiocirculary system." GMS German Medical Science 8 (2010): Doc12.
Habicher, M., et al. "S3 guidelines on intensive medical care of cardiac surgery patients: Hemodynamic monitoring and cardiovascular system—an update." Der Anaesthesist 67 (2018): 375-379.
Osawa, Eduardo A., et al. "Effect of perioperative goal-directed hemodynamic resuscitation therapy on outcomes following cardiac surgery: a randomized clinical trial and systematic review." Critical care medicine 44.4 (2016): 724-733.
André, Arthur C. St, and Anthony DelRossi. "Hemodynamic management of patients in the first 24 hours after cardiac surgery." Critical care medicine 33.9 (2005): 2082-2093.
Cengic, Sabina, et al. "Hypotension after intensive care unit drop-off in adult cardiac surgery patients." World Journal of Critical Care Medicine 9.2 (2020): 20.
He, Guo-Wei, and David P. Taggart. "Spasm in arterial grafts in coronary artery bypass grafting surgery." The Annals of thoracic surgery 101.3 (2016): 1222-1229.
Nadella, V., and S. J. Howell. "Hypertension: pathophysiology and perioperative implications." BJA Education 15.6 (2015): 275-279.
Estafanous, Fawzy G., and Robert C. Tarazi. "Systemic arterial hypertension associated with cardiac surgery." The American Journal of Cardiology 46.4 (1980): 685-694.
Estafanous, F. George, et al. "Systemic hypertension following myocardial revascularization." American Heart Journal 85.6 (1973): 732-738.
Viljoen, John F., F. George Estafanous, and Robert C. Tarazi. "Acute hypertension immediately after coronary artery surgery." The Journal of Thoracic and Cardiovascular Surgery 71.4 (1976): 548-550.
Buckberg, G. D., et al. "Experimental subendocardial ischemia during left ventricular hypertension." Surgical forum. Vol. 22. American College of Surgeons, 1971.
Liard, Jean-Francois, et al. "Hemodynamic and humoral characteristics of hypertension induced by prolonged stellate ganglion stimulation in conscious dogs." Circulation Research 36.3 (1975): 455-464.
Manobra de recrutamento alveolar na reversão da hipoxemia no pós-operatório imediato em cirurgia cardíaca.
McIlroy, David, et al. "Association of postoperative blood pressure and bleeding after cardiac surgery." The Journal of Thoracic and Cardiovascular Surgery 158.5 (2019): 1370-1379.
Vuylsteke, Alain, et al. "Perioperative blood pressure control: a prospective survey of patient management in cardiac surgery." Journal of cardiothoracic and vascular anesthesia 14.3 (2000): 269-273.
Meng, Lingzhong, et al. "Blood pressure targets in perioperative care: provisional considerations based on a comprehensive literature review." Hypertension 72.4 (2018): 806-817.
Eagle, Kim A., et al. "ACC/AHA 2004 guideline update for coronary artery bypass graft surgery: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1999 Guidelines for Coronary Artery Bypass Graft Surgery)." Circulation 110.14 (2004): e340.
Engelman, Daniel T., et al. "Guidelines for perioperative care in cardiac surgery: enhanced recovery after surgery society recommendations." JAMA surgery 154.8 (2019): 755-766.
Johnston, I. G., et al. "The pulmonary artery catheter in Australasia: a survey investigating intensive care physicians’ knowledge and perception of future trends in use." Anaesthesia and intensive care 36.1 (2008): 84-89.
Perry, Luke A., et al. "Trends in pulmonary artery catheter use for cardiac surgery, 2013–2023: Analysis of Australian medicare data." Critical Care and Resuscitation 27.2 (2025): 100100.
Hajjar, L., et al. "Vasopressin Versus Norepinephrine for the Management of Shock After Cardiac Surgery (VaNCS study): a randomized controlled trial." Critical Care17.Suppl 2 (2013): P222.
Wang, Dashuai, et al. "Incidence, risk factors, and outcomes of severe hypoxemia after cardiac surgery." Frontiers in Cardiovascular Medicine 9 (2022): 934533.
Ji, Qiang, et al. "Study on the risk factors of postoperative hypoxemia in patients undergoing coronary artery bypass grafting." Circulation Journal 72.12 (2008): 1975-1980.
Yahagi, Naoki, et al. "Helium/oxygen breathing improves hypoxemia after cardiac surgery." Artificial organs 21.1 (1997): 24-27.
Drains
Lobdell, Kevin W., et al. "Drainology: Leveraging research in chest-drain management to enhance recovery after cardiothoracic surgery." JTCVS techniques 25 (2024): 226.
Taylor, Anne C., Katherine E. Bates, and Alaina K. Kipps. "Variability in paediatric cardiac postoperative chest tube management." Cardiology in the Young 28.12 (2018): 1471-1474.
Utter, Garth H. "The rate of pleural fluid drainage as a criterion for the timing of chest tube removal: theoretical and practical considerations." The Annals of thoracic surgery 96.6 (2013): 2262-2267.
Andreasen, Jan J., et al. "Early chest tube removal following cardiac surgery is associated with pleural and/or pericardial effusions requiring invasive treatment." European Journal of Cardio-Thoracic Surgery 49.1 (2016): 288-292.
El-Akkawi, Ali Imad, et al. "Timing of chest tube removal following adult cardiac surgery: a cluster randomized controlled trial." Scandinavian Cardiovascular Journal 58.1 (2024): 2294681.
Heydari, Abbas, Zahra Sadat Manzari, and Masoud Abdollahi. "The right time for chest tube removal in the patient with cardiac surgery: a systematic review." Archives of Anesthesia and Critical Care (2021).
Drains that are blocked
Henry, Daniel A., et al. "The post-cardiac surgery chest radiograph: a clinically integrated approach." Journal of thoracic imaging 4.3 (1989): 20-41.
Karimov, Jamshid H., et al. "Incidence of chest tube clogging after cardiac surgery: a single-centre prospective observational study." European Journal of Cardio-Thoracic Surgery 44.6 (2013): 1029-1036.
Boyle Jr, Edward M., et al. "Retained blood syndrome after cardiac surgery: a new look at an old problem." Innovations 10.5 (2015): 296-303.
Engelman, Daniel T., et al. "Guidelines for perioperative care in cardiac surgery: enhanced recovery after surgery society recommendations." JAMA surgery 154.8 (2019): 755-766.
Loughran, Patrick. "Stripping or Milking of Chest Tubes." Critical Care Nurse 39.3 (2019): 72-73.
Lim-Levy, Fidelita, et al. "Is milking and stripping chest tubes really necessary?." The Annals of thoracic surgery 42.1 (1986): 77-80.
Halm, Margo A. "To strip or not to strip? Physiological effects of chest tube manipulation." American journal of critical care 16.6 (2007): 609-612.
Duncan, Carol, and Roberta Erickson. "Pressures associated with chest tube stripping." Heart & lung: the journal of critical care 11.2 (1982): 166-171.
Wallen, Margaret A., et al. "Mediastinal chest drain clearance for cardiac surgery." Cochrane Database of Systematic Reviews 2 (2002).
Analgesia
Nussmeier, Nancy A., et al. "Complications of the COX-2 inhibitors parecoxib and valdecoxib after cardiac surgery." New England Journal of Medicine 352.11 (2005): 1081-1091.
Devlin, John W., et al. "Clinical practice guidelines for the prevention and management of pain, agitation/sedation, delirium, immobility, and sleep disruption in adult patients in the ICU." Critical care medicine 46.9 (2018): e825-e873.
Hughes, Christopher G., et al. "American society for enhanced recovery and perioperative quality initiative joint consensus statement on postoperative delirium prevention." Anesthesia & Analgesia 130.6 (2020): 1572-1590.
Hu, Qinxue, et al. "Comparing different postoperative sedation strategies for patients in the intensive care unit after cardiac surgery: A systematic review of randomized controlled trials and network meta‐analysis." Basic & Clinical Pharmacology & Toxicology 135.2 (2024): 180-194.
Lobova, Veronika A., John M. Roll, and Marshall LC Roll. "Intraoperative methadone use in cardiac surgery: a systematic review." Pain Medicine 22.12 (2021): 2827-2834.
Rollins, Katie E., et al. "The impact of peri-operative intravenous lidocaine on postoperative outcome after elective colorectal surgery: a meta-analysis of randomised controlled trials." European Journal of Anaesthesiology| EJA 37.8 (2020): 659-670.
Li, Man, et al. "Enhanced recovery after surgery pathway for patients undergoing cardiac surgery: a randomized clinical trial." European journal of cardio-thoracic surgery 54.3 (2018): 491-497.
Rafiq, Sulman, et al. "Multimodal analgesia versus traditional opiate based analgesia after cardiac surgery, a randomized controlled trial." Journal of cardiothoracic surgery 9 (2014): 1-8.
Ralley, Fiona E., Fergal J. Day, and Davy CH Cheng. "Pro: nonsteroidal anti-inflammatory drugs should be routinely administered for postoperative analgesia after cardiac surgery." Journal of cardiothoracic and vascular anesthesia 14.6 (2000): 731-734.
Abou-Arab, Osama, et al. "Nonsteroidal antiinflammatory drugs used in cardiac surgery: a survey of practices and new insights for future studies." Journal of cardiothoracic and vascular anesthesia 38.1 (2024): 349-351.
Huette, Pierre, et al. "Effect of non-steroidal anti-inflammatory drugs on the management of postoperative pain after cardiac surgery: a multicenter, randomized, controlled, double-blind trial (KETOPAIN Study)." Trials 25.1 (2024): 613.
Grant, Michael C., et al. "Pain management and opioid stewardship in adult cardiac surgery: Joint consensus report of the PeriOperative Quality Initiative and the Enhanced Recovery After Surgery Cardiac Society." The Journal of thoracic and cardiovascular surgery 166.6 (2023): 1695-1706.
Electrolytes
Qureshi, Mashal, et al. "Determinants of atrial fibrillation after cardiac surgery." Reviews in Cardiovascular Medicine 22.2 (2021): 329-341.
Nyström, U., et al. "Oral sotalol reduces the incidence of atrial fibrillation after coronary artery bypass surgery." The Thoracic and cardiovascular surgeon 41.01 (1993): 34-37.
Greenberg, Jason W., et al. "Postoperative atrial fibrillation following cardiac surgery: a persistent complication." European Journal of Cardio-Thoracic Surgery 52.4 (2017): 665-672.
Lancaster, Timothy S., et al. "Potassium and magnesium supplementation do not protect against atrial fibrillation after cardiac operation: a time-matched analysis." The Annals of thoracic surgery 102.4 (2016): 1181-1188.
Polderman, Kees H., and Armand RJ Girbes. "Severe electrolyte disorders following cardiac surgery: a prospective controlled observational study." Critical Care 8 (2004): 1-8.
Sousa-Uva*, Miguel, et al. "2017 EACTS Guidelines on perioperative medication in adult cardiac surgery." European Journal of Cardio-Thoracic Surgery 53.1 (2018): 5-33.
Miller, S., et al. "Effects of magnesium on atrial fibrillation after cardiac surgery: a meta-analysis." Heart 91.5 (2005): 618-623.
Zhao, Kai, et al. "Associations between serum electrolyte and short-term outcomes in patients with acute decompensated heart failure." Annals of Medicine 55.1 (2023): 155-167.
Švagždienė, Milda, and Edmundas Širvinskas. "Changes in serum electrolyte levels and their influence on the incidence of atrial fibrillation after coronary artery bypass grafting surgery." Medicina (Kaunas) 42.3 (2006): 208-14.
Švagždienė, Milda, et al. "Atrial fibrillation and changes in serum and urinary electrolyte levels after coronary artery bypass grafting surgery." Medicina 45.12 (2009): 960.
Polderman, Kees H., and Armand RJ Girbes. "Severe electrolyte disorders following cardiac surgery: a prospective controlled observational study." Critical Care 8 (2004): 1-8.
Pramanik, S., et al. "Investigating pre and post-operative blood gases and serum electrolyte in patients undergoing coronary artery bypass surgery (CABG)." International Journal of Clinical Biochemistry and Research 4 (2017): 149-53.
Brinsfield, Dorothy, et al. "Body fluids and electrolytes after prolonged cardiopulmonary bypass." Journal of Applied Physiology 19.4 (1964): 566-570.
Coagulopathy
Taneja, Ravi, et al. "Minimum protamine dose required to neutralize heparin in cardiac surgery: A single-centre, prospective, observational cohort study." Canadian Journal of Anesthesia/Journal canadien d'anesthésie 70.2 (2023): 219-227.
Koster, Andreas, et al. "Protamine overdose and its impact on coagulation, bleeding, and transfusions after cardiopulmonary bypass: results of a randomized double-blind controlled pilot study." Clinical and Applied Thrombosis/Hemostasis 20.3 (2014): 290-295.
Lorenz, I., et al. "Activated clotting time (ACT) measuring devices used simultaneously do not produce correlating ACT values." Critical Care 11 (2007): 1-1.
Thenappan, Thenappan, et al. "Interchangeability of activated clotting time values across different point-of-care systems." The American journal of cardiology 109.9 (2012): 1379-1382.
Plebani, Mario, et al. "Point-of-care testing: state-of-the art and perspectives." Clinical Chemistry and Laboratory Medicine (CCLM) 63.1 (2025): 35-51.
Čeke, Lejla Selimović, et al. "Changes in activated partial thromboplastin time and international normalised ratio after on-pump and off-pump surgical revascularization of the heart." Bosnian Journal of Basic Medical Sciences 14.2 (2014): 70.
Ikić, Višnja. "Fibrinogen and bleeding in adult cardiac surgery: a review of the literature." Surgeries 2.4 (2021): 409-436.
Gielen, Chantal LI, et al. "Hemostatic alterations during coronary artery bypass grafting." Thrombosis Research 140 (2016): 140-146.
Temperature
Nussmeier, Nancy A. "Management of temperature during and after cardiac surgery." Texas Heart Institute Journal/from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 32.4 (2005): 472.
Grigore, Alina M., et al. "The rewarming rate and increased peak temperature alter neurocognitive outcome after cardiac surgery." Anesthesia & Analgesia 94.1 (2002): 4-10.
Rauch, Simon, et al. "Perioperative hypothermia—a narrative review." International Journal of Environmental Research and Public Health 18.16 (2021): 8749.
Haji-Jafari, Somayeh, et al. "The effect of rewarming on hemodynamic parameters and arterial blood gases of patients after open-heart surgery: A randomized controlled trial." Journal of Vascular Nursing 41.1 (2023): 29-35.
Bezerra, Amanda Silva de Macêdo, et al. "Effect of nurse-initiated forced-air warming blanket on the reduction of hypothermia complications following coronary artery bypass grafting: a randomized clinical trial." European Journal of Cardiovascular Nursing 20.5 (2021): 445-453.
Fever
O’Mara, Susan K. "Management of postoperative fever in adult cardiac surgical patients." Dimensions of Critical Care Nursing 36.3 (2017): 182-192.
Rostami, Mojtaba, Mohsen Mirmohammadsadeghi, and Hossein Zohrenia. "Evaluating the frequency of postoperative fever in patients with coronary artery bypass surgey." ARYA atherosclerosis 7.3
Lim, Eric, et al. "Pyrexia after cardiac surgery: natural history and association with infection." The Journal of Thoracic and Cardiovascular Surgery 126.4 (2003): 1013-1017. (2011): 119.
Santonocito, Cristina, et al. "C–reactive protein kinetics after cardiac surgery: a retrospective multicenter study." Annals of cardiac anaesthesia 25.4 (2022): 498-504.
Zukowska, Agnieszka, and Maciej Zukowski. "Surgical site infection in cardiac surgery." Journal of clinical medicine 11.23 (2022): 6991.
Wang, Dashuai, et al. "Risk factors for postoperative pneumonia after cardiac surgery: a prediction model." Journal of thoracic disease 13.4 (2021): 2351.
Massart, Nicolas, et al. "Mortality due to hospital-acquired infection after cardiac surgery." The Journal of thoracic and cardiovascular surgery 163.6 (2022): 2131-2140.
Giuliano, Karen K., et al. "Incidence, mortality, and cost trends in nonventilator hospital-acquired pneumonia in medicaid beneficiaries, 2015-2019." American journal of infection control 51.2 (2023): 227-230.
Gorski, Armin, et al. "Cardiac surgery antibiotic prophylaxis and calculated empiric antibiotic therapy." Asian Cardiovascular and Thoracic Annals 23.3 (2015): 282-288.
Hranjec, Tjasa, et al. "Aggressive versus conservative initiation of antimicrobial treatment in critically ill surgical patients with suspected intensive-care-unit-acquired infection: a quasi-experimental, before and after observational cohort study." The Lancet infectious diseases 12.10 (2012): 774-780.
Hortal, Javier, et al. "Incidence and risk factors for ventilator-associated pneumonia after major heart surgery." Intensive care medicine 35 (2009): 1518-1525.
Lactate
Maillet, Jean-Michel, et al. "Frequency, risk factors, and outcome of hyperlactatemia after cardiac surgery." Chest 123.5 (2003): 1361-1366.
Agitation
Heily, Meredith, et al. "Agitation during anaesthetic emergence: An observational study of adult cardiac surgery patients in two Australian intensive care units." Australian Critical Care 37.1 (2024): 67-73.
Gardner, Genevieve, et al. "Patient experiences following cardiothoracic surgery: an interview study." European Journal of Cardiovascular Nursing 4.3 (2005): 242-250.
Night-time extubation
Cheng, Davy CH, et al. "Morbidity outcome in early versus conventional tracheal extubation after coronary artery bypass grafting: a prospective randomized controlled trial." The Journal of thoracic and cardiovascular surgery 112.3 (1996): 755-764.
Gershengorn, Hayley B., et al. "Association of overnight extubation with outcomes after cardiac surgery in the intensive care unit." The Annals of thoracic surgery 108.2 (2019): 432-442.
Grant, Michael C. "Extubation after cardiac surgery: it’s better early, if often." The Annals of Thoracic Surgery 118.3 (2024): 699-700.