What factors are associated with decisions to withdraw mechanical ventilation in the intensive care unit?
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* Tushar Mahambrey
* Robert Fowler

*   © 2004 Canadian Medical Association or its licensors

Cook D, Rocker G, Marshall J, Sjokvist P, Dodek P, Griffith L, et al, for the Level of Care Study Investigators and the Canadian Critical Care Trials Group. Withdrawal of mechanical ventilation in anticipation of death in the intensive care unit. *N Engl J Med* 2003;349:1123-32.

Background: Mechanical ventilation is the most common form of advanced life-support used in the intensive care unit (ICU) and the one most often withdrawn in anticipation of death. The factors associated with decisions to withdraw mechanical ventilation in anticipation of death are unclear.

Design: This prospective multicentre, international observational study followed adults admitted to ICUs who were receiving mechanical ventilation. All patients were expected to be in the ICU for at least 72 hours. 

Results: Of the 851 patients who were enrolled, the mean age was 61.2 years and the mean Acute Physiology and Chronic Health Evaluation (APACHE II) score was 21.7. (The APACHE II measures the severity of acute and chronic illness on a scale of 0 to 71.) Most patients (539 [63.3%]) were successfully weaned from the ventilator; 146 (17.2%) died while receiving mechanical ventilation; and 166 (19.5%) had mechanical ventilation withdrawn. 

Compared with patients who died while receiving mechanical ventilation, those who ultimately had the ventilator withdrawn were significantly older (64.4 v. 60.1 years, *p* = 0.02), less likely to receive inotropes or vasopressors (69.3% v. 89.7%; *p* < 0.001) and more likely to have dialysis withdrawn (56.2% v. 25%, *p* = 0.01). By multivariate analysis, the strongest independent predictors of withdrawal of ventilation were the physician's prediction of poor patient outcome and perception that the patient did not want advanced life support (Table 1).

View this table:
[Table1](http://www.cmaj.ca/content/170/4/466/T1)

Table 1. 

Commentary: Among patients receiving mechanical ventilation in an ICU, 42.7% ultimately died. Cook and colleagues have focused on the group of patients for whom mechanical ventilation was withdrawn in anticipation of death, a surprising 19.5% of all mechanically ventilated patients. The authors have demonstrated that, rather than age or severity of illness or organ dysfunction, the strongest predictors of withdrawal of mechanical ventilation included the physician's perception that a patient preferred not to use life support and the physician's predictions of a low likelihood of hospital discharge or survival. 

However, we do not know the most influential clinical factors that enabled physicians to form such opinions, nor the methods of ascertaining patients' perceived wishes. Only 16.3% of the patients for whom ventilation was withdrawn were able to participate in decisions on admission to the ICU. The results may represent a self-fulfilling prophecy: if the treating physician believed that a patient was very likely to die or would not want mechanical ventilation, the physician may have been more likely to support withdrawal of ventilation. The authors highlight previous research showing that physician's personal characteristics and experiences may influence their style of decision-making. Also, although the numbers are small, it is surprising that 6 of 166 patients who had ventilation withdrawn in anticipation of imminent death ultimately survived and were discharged from hospital. Although the study enrolled patients from 4 countries, the findings may not be generalizable to all settings. A recently published study showed that end-of-life practices in European critical care units differed markedly according to geography and patient religion.1 

This study by Cook and colleagues sheds light on an extremely important component of end-of-life care, withdrawal of life support. We hope that their findings will stimulate further examination of the process by which patients' preferences are determined and acted upon when physicians make the decision to withdraw advanced life support.

**Tushar Mahambrey** Critical Care Fellow **Robert Fowler** Assistant Professor Divisions of General Internal Medicine and Critical Care Medicine Sunnybrook and Women's College Health Sciences Centre Toronto, Ont.

## Reference

1.  1. Sprung CL, Cohen SL, Sjokvist P, Baras M, Bulow HH, Hovilehto S, et al. End-of-life practices in European intensive care units: the Ethicus study. JAMA 2003;290:790-7.
    
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