FREE NEJM E-TOC    HOME   |   SUBSCRIBE   |   CURRENT ISSUE   |   PAST ISSUES   |   COLLECTIONS   |   Search Term  Advanced Search

Sign in | Get NEJM's E-Mail Table of Contents — Free | Subscribe

Abstract Full Text

Supplement to Nuckton TJ et al. Pulmonary Dead-Space Fraction as a Risk Factor for Death in the Acute Respiratory Distress Syndrome. N Engl J Med 2002;346:1281-6.

Supplementary Appendix 1

We examined the following variables individually for a possible association with the risk of death, using logistic regression: age, sex, ideal body weight,² the absolute tidal volume, the tidal volume per kilogram of ideal body weight, the respiratory rate, minute ventilation, positive end-expiratory pressure, pH, the partial pressure of arterial carbon dioxide, the ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen, quasistatic respiratory compliance, the lung-injury score,^{29, 30} and the oxygenation index.⁶ The following laboratory values were also evaluated: sodium, potassium, blood urea nitrogen, creatinine, white-cell count, neutrophil count, hematocrit, platelet count, prothrombin time, albumin, and total bilirubin.

Nonpulmonary organ system dysfunction^4,5,27 was defined as follows: hematologic dysfunction, fewer than 75,000 platelets or a white-cell count of less than 1000 per cubic millimeter or the presence of disseminated intravascular coagulation; renal dysfunction, a creatinine concentration of more than 2.0 mg per deciliter (177 µmol per liter) or the use of hemodialysis or hemofiltration; neurologic dysfunction, obtundation that was not pharmacologically induced or primary evidence of a central nervous system abnormality; cardiac dysfunction, evidence of acute myocardial infarction or abnormal findings on echocardiography; hepatic dysfunction, a total serum bilirubin concentration of more than 2 mg per deciliter (34 µmol per liter), along with a prothrombin time that was more than 3 seconds longer than a control value; and gastrointestinal dysfunction, ileus lasting greater than 24 hours, gastrointestinal bleeding requiring treatment, or diarrhea. The presence or absence of each type of nonpulmonary organ system dysfunction and the number of nonpulmonary organ systems involved were examined.

The reason for admission (unscheduled surgery, scheduled surgery, or medical care) and a Simplified Acute Physiology Score II²⁸ obtained on the day that dead space was measured, were also examined. The primary clinical disorder associated with the acute respiratory distress syndrome (sepsis, aspiration, pneumonia, or other [trauma, overdose, fat emboli, or unknown]) was examined, as was the presence or absence of the following: diabetes mellitus, cirrhosis, history of alcohol abuse, history of intravenous drug use, acquired immunodeficiency syndrome, vasopressor use (defined as the use of multiple vasopressors or the receipt of more than 4 µg of either dobutamine or dopamine alone per kilogram of body weight per minute), cancer (solid tumors and hematologic cancers were studied independently), organ transplantation (including liver and bone marrow transplantation together and individually), and the use of a low tidal volume (6 ml per kilogram of ideal body weight) as a lung-protection strategy.² Sepsis, which was defined on the basis of a previously used definition⁴ and was classified independently from the analysis of the cause of the acute respiratory distress syndrome, was also examined on the day of the wasted-ventilation measurement, according to body temperature (more than 38.0°C or less than 35.0°C), the presence of a systolic blood pressure of less than 90 mm Hg or the use of vasopressors, and the presence of a clinically identifiable source of infection.

Abstract Full Text