Critical Care Trials Group Research Articles

Does transfusion practice affect mortality in critically ill patients? Transfusion Requirements in Critical Care (TRICC) Investigators and the Canadian Critical Care Trials Group.

In 4,470 critically ill patients, we examined the impact of transfusion practice on mortality rates. As compared with survivors, patients who died in intensive care units (ICU) had lower hemoglobin values (95 +/- 26 versus 104 +/- 23 g/L, p < 0.0001) and were transfused red cells more frequently (42.6% versus 28.0%, p < 0.0001). In patients with cardiac disease, there was a trend toward an increased mortality when hemoglobin values were < 95 g/L (55% versus 42%, p = 0.09) as compared with anemic patients with other diagnoses. Patients with anemia, a high APACHE II score (> 20), and a cardiac diagnosis had a significantly lower mortality rate when given 1 to 3 or 4 to 6 units of allogeneic red cells (55% [no transfusions] versus 35% [1 to 3 units] or 32% [4 to 6 units], respectively, p = 0.01). Adjusted odds ratio (OR) predicting survival were 0.61 (95% CI; 0.37 to 1.00, p = 0.026) after 1 to 3 units and 0.49 (95% CI; 0.23 to 1.03, p = 0.03) after 4 to 6 units compared with nontransfused anemic patients. In the subgroup with cardiac disease, increasing hemoglobin values in anemic patients was associated with improved survival (OR = 0.80 for each 10 g/L increase, p = 0.012). We conclude that anemia increases the risk of death in critically ill patients with cardiac disease. Blood transfusions appear to decrease this risk.

Name of Study Participant Omitted.

—In the Original Contribution entitled "Transfusion Requirements in Critical Care: A Pilot Study," published in the May 10, 1995, issue ofTHE JOURNAL(1995;273: 1439-1444), Jaime Pinilla, MD, Royal University Hospital, Saskatoon, Saskatchewan, should be listed on page 1444 as a study participant in the Canadian Critical Care Trials Group.

Withdrawing Life Support in Canada and the United States-Reply

In Reply. —We thank Dr Whittaker for her thoughtful comments interpreting our study in the framework of the US health care system. There is no direct evidence about differences between United States and Canadian intensivists in decision making about the withholding and withdrawing of life support. In contrast to Whittaker, colleagues in the Canadian Critical Care Trials Group who have worked in both countries have found more similarities than differences in approach. At the same time, there are definite cultural issues that may affect the care that is delivered, including individualist vs socialist perspectives, financial incentives for health care providers, technological access, and the threat of litigation. By design, we focused on the attitudes and beliefs of ICU health care workers, in isolation of patient advance directives, family wishes, ability to pay, or other resource constraints. We agree that consideration of these issues would be important in any research program

Transfusion requirements in critical care. A pilot study. Canadian Critical Care Trials Group

Transfusion requirements in critical care. A pilot study. Canadian Critical Care Trials Group

Determinants in Canadian health care workers of the decision to withdraw life support from the critically ill. Canadian Critical Care Trials Group

To examine the attitudes of health care workers regarding the withdrawal of life support. Cross-sectional survey. Attending staff, house staff, and intensive care unit (ICU) nurses in 37 Canadian university-affiliated hospitals. Health care workers' ratings of the importance of 17 factors considered in the decision to withdraw life support, and their ratings of five levels of care ranging from comfort measures to intensive care in two of 12 different clinical scenarios. We surveyed 1361 respondents (149 of 167 potentially eligible ICU attending staff, 142 of 173 ICU house staff, and 1070 of 1455 ICU nurses, with response rates of 89%, 82% and 74%, respectively). The most important factors were likelihood of surviving the current episode, likelihood of long-term survival, premorbid cognitive function, and age of the patient. In choosing the level of care for the patient scenarios, the same option was chosen by more than 50% of respondents in only one of 12 scenarios; opposite extremes of care were chosen by more than 10% of the respondents in eight of 12 scenarios. Respondent characteristics affecting choices included the number of years since graduation, the city and province in which they worked, the number of beds in their ICU, and their assessment of the likelihood that they would withdraw life support in comparison with their colleagues (P < .001 for all comparisons). While ICU health care workers consistently identify a number of patient factors as important in decisions to withdraw care, there is extreme variability, which may be explained in part by the values of individual health care providers.

Risk factors for gastrointestinal bleeding in critically ill patients. Canadian Critical Care Trials Group.

The efficacy of prophylaxis against stress ulcers in preventing gastrointestinal bleeding in critically ill patients has led to its widespread use. The side effects and cost of prophylaxis, however, necessitate targeting preventive therapy to those patients most likely to benefit. We conducted a prospective multicenter cohort study in which we evaluated potential risk factors for stress ulceration in patients admitted to intensive care units and documented the occurrence of clinically important gastrointestinal bleeding (defined as overt bleeding in association with hemodynamic compromise or the need for blood transfusion). Of 2252 patients, 33 (1.5 percent; 95 percent confidence interval, 1.0 to 2.1 percent) had clinically important bleeding. Two strong independent risk factors for bleeding were identified: respiratory failure (odds ratio, 15.6) and coagulopathy (odds ratio, 4.3). Of 847 patients who had one or both of these risk factors, 31 (3.7 percent; 95 percent confidence interval, 2.5 to 5.2 percent) had clinically important bleeding. Of 1405 patients without these risk factors, 2 (0.1 percent; 95 percent confidence interval, 0.02 to 0.5 percent) had clinically important bleeding. The mortality rate was 48.5 percent in the group with bleeding and 9.1 percent in the group without bleeding (P < 0.001). Few critically ill patients have clinically important gastrointestinal bleeding, and therefore prophylaxis against stress ulcers can be safely withheld from critically ill patients unless they have coagulopathy or require mechanical ventilation.