ICU exit block

ICU exit block is lumped together with handwashing and CVAD infections under Section 2.3.1, "Safety and quality / Key performance indicators in ICU ", in the second edition of the CICM Syllabus for the Second Part Examination. This seems unfair, given that it occupies a dominant position in the agenda items presented by ICU directors for discussion with hospital administrators and other heads of department. It is fortunate that ICU trainees are largely insulated from those conversations, but they do get dragged in indirectly, when they find themselves looking after ward-stable patients for many hours, while the critically ill are waiting in various recovery bays and emergency departments. 

Question 4 from the first paper of 2025 was the first to tackle this problem, presenting the trainees with a depressing graph showing that the bulk of a hypthetical ICU's discharges were occurring in the afternoon or evening. "The understanding of how unit workflow interacts with broader concerns within the hospital and the effect on patient care was a marker of the superior answer", the examiners commented. Though it could be said that the factors involved are frequently not within the control of the ICU (so why ask about them?), the contraryu position would hold this understanding as essential for practicing responsibly as a citizen of the hospital community. You need to see and understand the problem so that you can advicate effectively for your unit when your seniority permits it.

So, what is a CICM Second Part exam candidate expected to know about this complex and prevalent problem? The syllabus only mentions "should be able to discuss the purpose and processes", which sounds like something that can be said about "Clinical audit" and "Incident reporting and review", but not so much the issues of patient flow and bed block. To derive more information, we can turn to the examiner comments for Question 4, where some headings and topics present themselves to help guide this chapter. 

In summary:

• Exit block is delay of discharge of ward-ready ICU patients by >6 hrs (>12  hrs for the ANZICS definition)
• Access block is delay of admission for critically ill patients  to the ICU (>6 hours) for any reason, eg. no available beds
• After-hours ICU discharge is defined as discharges occurring between 18:00 and 06:00
• Other KPI measures of ICU exit/access block include the number of deferred or cancelled elective surgical cases, and the patients who needed to be transferred to another ICU
• Epidemiology of ICU bed block:
  • Optimal ICU capacity is ~ 70-75%; most Australian ICUs are 80-85%, some notable outliers are often >100%
  • ~19% of ICU patients are discharged after hours on average, up to 60% in some units
  • ~20% have their discharge delayed by >12 hrs
• Causes of exit block
  • High patient acuity: Increased patient monitoring or supervision requirements, increased patient nursing workload requirements
  • ICU factors: decreased staffing, poor communication of discharge decisions, or decisions delayed
  • Hospital factors: service strain, bed capacity, understaffing, delays of discharging patients on weekend and holidays 
• Consequences of exit block
  • Access block for the ED and wards
  • Cancellation of elective surgery
  • Inefficient use of ICU resources
  • ICU staff burnout
  • Numerous ward-ready patients = reduced ICU training opportunities
  • Delayed rehabilitation
  • Ineffective handover during rushed discharge
  • Prolonged exposure to the ICU environment (noise, sleep deprivation, nosocomial resistant infectious agents)
  • Discharges delayed until after hours 
• Consequences of after hours discharge
  • Increased mortality, ICU readmission, hospital stay
  • Causes of this are unknown (? reduced vigilance in the ward at night, poorer handover, delayed specialist attention, premature discharge, or a overall sign of increased strain in the system

Where is this coming from? The definition of all our key performance indicators comes from the Australian Commission on Safety and Quality in Health, and these are sufficiently similar across health services worldwide. 

Definition of ICU exit block

" ICU Exit block describes the inability to discharge a patient from the ICU who is otherwise medically fit to leave, due to no available ward beds, limited clinical or ancillary staffing levels in the wards, and so on."

- Intensive Care Clinical Indicators version 4, ACHS

This integrates well with the definition of access block, which is the inevitable consequence of exit block:

"ICU Access block describes a delay in admission of a patient to the ICU for any reason, such as no available beds, limited clinical staffing levels in the ICU, and so on. This does not include where a specialist ICU service, for example extracorporeal membrane oxygenation (ECMO), is not available in that ICU."

These largely speak for themselves. Interestingly, they have become a key performance indicator for the ICU mostly because of non-patient-centred and certainly non-ICU-centered concerns. Consider: for a patient already in ICU, recovering from critical illness, the practical disadvantages of remaining in ICU are fairly trivial. One is exposed to more beeping and alarms than usual, and the activity of the unit is hardly conducive to a restful night of sleep, but otherwise it is not harmful, and potentially even beneficial. Gilligan (2017), discussing the Boschian hellscape of the NHS, rolls this concept over and over, thoughtfully, to conclude that the data actually supports the prolongation of stay for some of the sicker patients, suggesting that the KPIs insisting on their discharge generate "a slightly perverse incentive against this cohort of patients". The harm of access block is undeniable - ICU patients belong in the ICU, and every other environment should be considered hostile to them (for example, keeping them in the ED increases their mortality by 35%). But the pragmatic intensivist would also counter that the patients under their direct responsibility are those currently admitted to their unit, and until care is handed over, the waiting access-blocked referrals are somebody elses' problem (as logically a department should be held accountable for the care of the patients while under their roof). 

Measures of ICU exit block

The ACHS wants to measure the following:

• Total number of adult patients whose discharge from the ICU was delayed more than 6 hours
• Total number of ICU admissions where the intensivist documented that the patient could not be admitted to the ICU because of a lack of resources
• Total number of adult elective surgical cases deferred or cancelled due to lack of an ICU bed
• Total number of adult patients who were transferred to another facility/ICU due to the unavailability of an ICU bed
• Total number of adult patients discharged from the ICU between 6pm and 6am

The attentive reader will call attention to the numbers, and perhaps even ask how we came up with these values. They were not chosen arbitrarily. For example, the 06:00-18:00 timeframe was chosen on the basis of an old study by Pilcher et al (2007), whose filtering of ANZICS data revealed this as the timeframe of highest mortality disadvantage (absolute difference of 2.7% in this early study of data from 2000-2004, that pre-dated the widespread establishment of medical emergency team services). Previous studies, the authors complained, were focused on timing their survival data according to the changes of medical or nursing shift. Why not let the outcomes decide? The result was a twelve-hour timeline from 6pm until 6am, out of step with medical start times (08:00), based on the risk-adjusted outcome across the 24-hour day.  

The six hour timeframe for exit block is a bit more challenging to unravbel the origins of. It seems to come from Bukata (2008), who noted that a six-hour delay to ICU admission was an independent risk factor for increased mortality in ED referrals. ANZICS use twelve hours as their benchmark, perhaps to be different. 

Epidemiology of ICU exit block

How did this happen? Becoming the curator of an expensive and limited resource has done this to us, and this happens anywhere closed ICUs are used (for example, in Germany).  Consider that the open ICU user-pays model of critical care in America (28-30 ICU beds per 100,000) does not seem to have produced the same volume of literature regarding exit block.  "It is now possible for there to be times when there are no available public ICU beds in the metropolitan hospitals of some major Australian cities", Scheinkestel complained in 1996; "in many major Australian ICUs, demand exceeds supply by as much as 10%".   The author can only laugh in the grim darkness of the future, when there is only block. The population of Western Sydney, where he practices, has almost tripled since 1996, but the ICU bed numbers have not kept up with the demand, leaving the ICU resources of Western Sydney well below the already depressing national average (5.8 beds per 100,000), i.e. provisioned no better than many developing nations. 

Health district	2025 population	Public ICU beds	Beds per 100,000 population
South Eastern Sydney LHD	936,902	124	13.24
Sydney LHD	705,482	81	11.48
Northern Sydney LHD	971,927	98	10.08
Nepean Blue Mountains LHD	389,402	36	9.45
National average			9.1
South Western Sydney LHD	1,088,957	86	7.90
Hunter New England LHD	984,437	74	7.52
Western Sydney LHD	1,089,181	63	5.78

The result is an unetanble situation where the ICU is perpetually at 110% capacity, with several patients waiting to be admitted at any given time. In contrast, observe the findings of  Tierney & Conroy (2014), who scoured the literature for any data regarding the exact amount of full an ICU should be (that number turned out to be 75% or so, for optimal system resilience). The natonal average in 2023/2024 was 83.1% occupancy for teriary ICUs, with an after-hours discharge rate of 18.8% on average, but up to 50%-60% in some ICUs in NSW; and an average rate of delayed discharge (by twelve hours) of 19.8%.

Causes of ICU exit block

To concentrate on the proximal causes of access and exit block tends to carry an intensivist too far from their sovereign territory and into the politics of other departments, which most would agree would be inappropriately colonialist. Consider, that the closed-collaborative model of Intensive Care relies on the contract that non-ICU specialities do not exert a controlling influence on the management of ICU patients, leaving that to the expertise of the intensivist; and so it is a matter of professional courtesy for the intensivist to leave non-ICU management to these specialities. What business is it of ours, how they choose to discharge or admit their patients? Certainly that is not something the ICU crowd should want to get involved with, one may offer from a particular kind of conservative vantage point.

On the other hand, the role of the intensivist should evolve from the provider of an organ support service to a policy designer, care planning decisionmaker and health ethicist. Alrteady in the ancient era of 1996 Scheinkestel argued that, by accepting the primary responsibility for the patient in a closed collaborative system, the Australian intensivist is inevitably involved in the decisionmaking around resource allocation, financial operation of the hospital, economic rationalism, and healthcare management. It is therefore imperative for us to get involved in all the aspects of patient flow, because we suffer if we leave it to others, a different viewpoint might argue.

Irrespective of which perspective sounds most appealing, the CICM appear to want their candidates to understand the underlying causes of this problem. The best reference for this was this ACI document which tabulates all the major factors into a tidy framework.

• Patient factors
  • Increased patient monitoring requirements: limited availability of high acuity discharge destinations (eg. HDU, close observation units, monitored telemetry beds)
  • Increased patient supervision requirements (eg. delirium)
  • Increased patient nursing workload requirements (eg. very frequent observations, such as Doppler pulses for a tenuously perfused flap, or hourly urine output, etc)
• ICU factors 
  • Degraded staffing (eg. unable to complete discharge decisionmaking or handover paperwork because of pressing  patient care demands)
  • Delayed communication of discharge decisions to bed managers
  • Mis-timed deescalation of care (eg. if the patient discharge decision is made at 2am, there is nobody around to action it)
•  System factors (downstream capacity constraints)
  • Hospital bed capacity
  • Weekend discharges: less medical workforce and attention to  discharging low acuity patients on weekends results in reduced hospital bed availability
  • Hospital discharge destinations may be limited (eg. by nursing home bed availability)
  • Low maximum care acuity for ward patients (ie. ward staff stretched too thin to accommodate patients with ongoing high care needs)

Consequences of ICU exit block

As mentioned above, for at least some of the patients, the extra time spend in the ICU is protective. From their perspective, there really is no problem. So what are the adverse effects of exit block from another viewpoint? Institution-level consequences:

• The ICU becomes a target of criticism when wider hospital KPIs are not met, eg. where length of stay is unduly prolonged, or where elective surgery needs to be cancelled because theatres recovery is too full of ICU patients waiting for beds
  • Staff morale suffers from the constant pressure to discharge patients, and by having to spend time maaging ward patients
  • The overall skill level is diluted because acuity is reduced
  • Exposure to training opportunities is reduced
• Population-level consequences
  • From a health economics perspective, the cost of a day of ICU stay is vastyly in excess of the cost of a typical ward bed, which suggests that moeny spent on ward patients in ICU beds is being wasted.
  • Where patients must be transferred from one ICU to another to make room, the cost is even greater.
• Patient consequences:
  • Access block: if exit block perpetuates high occupancy, then critically ill patients wait for ICU beds, and their mortality increases (as described above)
  • Prolonged exposure to the ICU environment (noise, sleep deprivation, nosocomial resistant infectious agents)
  • Delayed rehabilitation or specialist attendance - try as we might to behave like physicians, we intensivists are basically creatures of the raw and ragged end of the acuity spectrum, whose skills are most useful when the patient is actively trying to die. On the other end of the severity range, we tend to have less training and expertise with managing patients who are past their critical illness, who need attention to their rehabilitation and long term management goals. Delayed ICU discharge can delay the patient's access to those specialist services.
  • Discharges occur under crisis conditions (eg. to bring a crashing patient into the ICU) which reduces the time available for complete documentation and thorough handover
  • Discharges are delayed until after hours, which is associated with increased mortality

Whigh begs the next question, why are the after-hours discharges so perilous?

Consequences of after-hours ICU discharges

There is just something slightly lethal about the hospital after dark.

• The association with increased mortality is real. it is observed across  The data, whether they are collected in the US, UK, Australia or elsewhere, shows that mortality is increased across the board in this group, which seems to be independent of the illness severity or treatment limitations (Moshynskyy et al, 2022) 
• There is also an association with increased ICU readmission and length of hospital stay

But why? 

• Nobody knows
• Potentially some are premature discharges (i.e. not all of these patients are delayed discharges)
• Higher proportion of patients with treatment limiations
• Inadequate or absent handover 
• Reduced vigilance by understaffed night services
• Delayed specialist attention
• A representation of increased strain in the system, suggesting that mortality across the board may be affected, but that this vilnerable population are at greatest riQuestion 4 from the first paper of 2025 only asked the candidates to  "outline the potential significance of this ...on patient care", which is not the same as "explain this phenomenon, even though nobody else can", so it is probably safe to repeat these speculations (nothing more concrete seems to have been expected). It appears the examiners would have accepted a range of discussion points, as no specific demands were made by them in their comments, other than to demonstrate "the understanding of how unit workflow interacts with broader concerns within the hospital".

Strategies to manage ICU exit block

So, what would you do about this. 

Well, the natural answer, which is "get more beds for the ICU and the hospital" is sure to be mocked at the next clinical governance committee meeting. You may as well just advise poor people to work harder and get more money. However, some strategies could be implemented, of which several originate within the ICU itself. Again these originate from the NSW ACI, given that NSW is the home of bed block. 

• Strategies at the level of the ICU:
  • Identify potential discharges early, to allow hospital bed managers to prepare with some notice
  • Improve communication with patient flow to identify barriers to discharge 
  • Expand the capacity to discharge patients directly home from the ICU by involving discharge planners in discharge destination decisions, and streamline the process of referral
• Involvement of hospital systems at the ICU level
  • Increased availability of cleaners to increase the speed of ICU bed turnover
  • Increased availability of funding to source junior/trainee nursing staff to provide 1:1 supervision for delirious patients, so that delirium is not a barrier to dicharge
  • Create opportunities for flexible ICU stepdown capacity by extending HDU bed numbers into repurposed recovery or ward facilities and cultivating a cadre of short-notice casual staff
  • Remove logistic barriers for ICU discharge by empowering the intensivist to be the main decisionmaker in determining the discharge destination
• Whole-institution solutions
  • Increase the availability of telemetry monitoring equipment to increase the range of available discharge destinations
  • Provide discharge lounges to patients waiting for discharge paperwork before home, thereby emptying beds
  • Provide dedicated monitored stepdown beds for ICU patients to be decanted into
  • Fund and deploy an  ICU post-discharge follow up service to increase the safety of ICU discharges and prevent readmission
  • Increase the staffing and supervision of the wards after hours to improve the safety of late discharges
  • Integrate ICU capacity management into patient flow priorities for the hospital
  • Impose time-based frameworks and KPIs on ward clinicians to prioritise discharges early in the day