This chapter deals with the investigations and resuscitation of massive bleeding into the abdominal cavity.
There are really two main sources in the abdomen where one can bleed torrentially: a ruptured abdominal aneurysm or a retroperitoneal hematoma.
The AAA is most common in male smokers.
The question is, when will it rupture?
In the presence of poorly controlled hypertension, these things tend to grow in diameter by about 3-5mm per year.
When it ruptures, one tends to have about 30% pre-hospital mortality, followed by a 40% perioperative mortality. And of course, it is almost uniformly fatal in patients who are not offered surgery. Which is a fair few - give the vascular disease profile which predisposes a person to AAA formation, one can expect that a fair few of these patients will have poor cardiorespiratory performance and poor quality of life.
But let us say you go ahead with the repair.
The key controversy is the target blood pressure. The patient is shocked and the lactate is rising; one may be tempted to react to this with fluids and vasopressors. However, this may not be the best strategy. After all, the aorta has a hole in it, and the systolic blood pressure is probably directly related to the rate of exsanguination though this defect. Authors have suggested a target systolic pressure of 70-80mmHg. It seems low, but it is a fair compromise - one simply has to accept that one's patient will progress equally in the direction of both bleeding to death and global hypoxic-ischaemic injury.
The key problem is induction of anaesthesia. The conscious ruptured AAA patient is in considerable pain, and their hemodynamic performance is largely reliant on their abdominal wall musculature contracting around their sore belly, tamponading the bleed. Consider now what might happen if you relax them with anaesthetic drugs and neuromuscular junction blockers. Now, nothing is putting pressure on the defect in the aorta. This is a recipe for a PEA arrest. The next phase of management should really be the cross-clamping of the aorta, which will result in a marked improvement of hemodynamic performance, but until the clamp is in place the anaesthetist is potentially stuck performing CPR on a bunch of empty ventricles.
The patient will ultimately return to ICU intubated.
There are several issues one wought to look out for in the returning post-AAA repair patient:
Why would you bleed into the retroperitoneal potential space? Well, you may have had some sort of procedure performed (eg. a renal biopsy). Or, trauma (eg. axe attack). Alternatively, you might have bled spontaneously, and this may be completely attributable to your anticoagulation therapy.
Aetiology of retroperitoneal haemorrhage
Renal biopsy has actually come up in an SAQ, in the sense that the bleeding complications following renal biopsy took up one entire 10-mark CICM exam question (Question 4 from the first paper of 2022). One can imagine how a questions like this could have been stimulated by somebody's really negative experience.
What could have caused such bleeding following a renal biopsy? Or to borrow from Question 4, what five factors could have contributed? Don't all immediately say "poor technique". To be sure, most people who work in ICU will notice a distinct concentration of these events at the beginning of the academic year, when new nephrology trainees are cavorting excitedly around the department, and we have all seen our share of renal biopsy results return as "normal arterial intima". However, there are also some modifiable and non-modifiable patient risk factors. Borrowing from The Boston kidney biopsy cohort (Palsson et al, 2020) and Whittier (2012), the following
Modifiable risk factors | Non-modifiable risk factors |
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Steps to reduce the risk of bleeding include:
But let's say they bled anyway. Apart from controlling the coagulopathy and replacing the lost blood, one has several treatment options.
Advantages:
Disadvantages:
Advantages:
Disadvantages:
Advantages:
Disadvantages:
Oh's Intensive Care manual: Chapter 45 (pp. 520) Abdominal surgical catastrophes by Stephen J Streat
Cho, Jae-Sung, et al. "Contemporary results of open repair of ruptured abdominal aortoiliac aneurysms: effect of surgeon volume on mortality." Journal of vascular surgery 48.1 (2008): 10-18.
Brimacombe, J., and A. Berry. "Haemodynamic management in ruptured abdominal aortic aneurysm." Postgraduate medical journal 70.822 (1994): 252-256.
Chan, Y. C., et al. "Management of spontaneous and iatrogenic retroperitoneal haemorrhage: conservative management, endovascular intervention or open surgery?." International journal of clinical practice 62.10 (2008): 1604-1613.
Sakalihasan, Natzi, Raymond Limet, and O. D. Defawe. "Abdominal aortic aneurysm." The Lancet 365.9470 (2005): 1577-1589.
Palsson, Ragnar, et al. "Bleeding complications after percutaneous native kidney biopsy: results from the Boston kidney biopsy cohort." Kidney International Reports 5.4 (2020): 511-518.
Whittier, William L. "Complications of the percutaneous kidney biopsy." Advances in chronic kidney disease 19.3 (2012): 179-187.