Monitoring patients in the intensive care unit after carotid endarterectomy
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* J.H. Wong
* J.M. Findlay

We are worried that Dr. Passerini’s suggestion that postoperative intensive care unit (ICU) monitoring of patients who have undergone carotid endarterectomy (CE) is unnecessary (*Can J Surg* 1996;39:99–104) will be adopted as a cost-saving measure in some centres without further scrutiny.

Based on her Table IV (page 103), she stated that the “absence of events in the RR [recovery room] had a negative predictive value of 97%,” implying that monitoring in the recovery room acts as a satisfactory screening test for postoperative complications. However, the data have been artificially forced into a two × two table format, since it is impossible to classify a patient who suffers a recovery-room complication as having no overall complication; this cell can be nothing other than zero. It is more proper to state that 97% (104 of 107) of those without complications in the recovery room continued to be free of major problems during their hospitalization. A more pessimistic view of the same data is that if the author’s recommendations had been in effect during the study period, 38% (three of eight) of all major complications developed beyond the recovery-room period, potentially on the surgical ward. Also, the study patients spent an average of 3.5 hours in the recovery room, a period of time that may differ significantly from that in other hospitals — our endarterectomy patients remain in the recovery room a mean of 63 minutes before routine transfer to the ICU.

It is difficult to accept the author’s strong conclusion that routine postoperative ICU care is unwarranted, since this study was an observational case series, lacking a control group for comparison. The routine ICU care that in fact occurred during this study may well have averted additional major complications. Clearly, whether or not ICU care prevents the development of, or progression to, significant complications will only be answered by a prospective controlled trial with randomization of care to either the ICU or general ward.

In Edmonton, hemodynamic instability is a common phenomenon after CE, developing in 62% of patients postoperatively.1 Previous cohort studies have linked postoperative fluctuations in blood pressure with major complications,2–4 and our experience is that severe postoperative systolic hypertension (greater than 220 mm Hg) is significantly associated with stroke and death. Although we believe that hemodynamic problems are best recognized and treated in an ICU setting, an acceptable compromise may be the use of intermediate care units with readily available arterial line monitoring and intravenous vasoactive agents.5

In these times of fiscal restraint, there are calls from all sides to restrict the use of expensive resources such as the ICU. However, since the question of whether ICU care actually prevents complications has not yet been answered, should not the surgeon’s argument be to err on the side of patient safety? Until we become more skilled in predicting which patients are at most risk, where we decide to care for our patients after CE will depend on surgeon preference and availability of ICU resources. We must ensure that our decision continues to be founded on medical grounds rater than financial concerns.

## References

1.  Wong JH, Findlay JM. Perioperative hemodynamic instability after carotid endarterectomy. Can J Neurol Sci 1996;23:S888.
    
    

2.  Bove EL, Fry WJ, Gross WS, Stanley JC. Hypotension and hypertension as consequences of baroreceptor dysfunction following carotid endarterectomy. Surgery 1979;85:633–7.
    
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3.  Benzel EC, Hoppens KD. Factors associated with postoperative hypertension complicating carotid endarterectomy. Acta Neurochir (Wien) 1991; 112:8–12.
    
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4.  Corson JD, Chang BB, Leopold PW, DeLeo B, Shah DM, Leather RP, et al. Perioperative hypertension in patients undergoing carotid endarterectomy: shorter duration under regional block anesthesia. Circulation 1986; 74(3 Pt 2):I1–4.
    
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5.  Findlay JM. Early discharge after carotid endarterectomy [letter]. Neurosurgery 1996;38:231–2.
    
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