Cardiopulmonary resuscitation directives on admission to intensive-care unit: an international observational study.

BACKGROUND: Resuscitation directives should be a sign of patient's preference. Our objective was to ascertain prevalence, predictors, and procurement pattern of cardiopulmonary resuscitation directives within 24 h of admission to the intensive-care unit (ICU). METHODS: We enrolled 2916 patients aged 18 years and older from 15 ICUs in four countries, and recorded whether, when, and by whom their cardiopulmonary resuscitation directives were established. By polychotomous logistic regression we identified factors associated with a resuscitate or do-not-resuscitate directive. FINDINGS: Of 2916 patients, 318 (11%; 95% CI 9.8-12.1) had an explicit resuscitation directive. In 159 (50%; 44.4-55.6) patients, the directive was do-not-resuscitate. Directives were established by residents for 145 (46%; 40.0-51.3) patients. Age strongly predicted do-not-resuscitate directives: for 50-64, 65-74, and 75 years and older, odds ratios were 3.4 (95% CI 1.6-7.3), 4.4 (2.2-9.2), and 8.8 (4.4-17.8), respectively. APACHE II scores greater than 20 predicted resuscitate and do-not-resuscitate directives in a similar way. An explicit directive was likely for patients admitted at night (odds ratio 1.4 [1.0-1.9] and 1.6 [1.2-2.3] for resuscitate and do-not-resuscitate, respectively) and during weekends (1.9 [1.3-2.7] and 2.2 [1.5-3.2], respectively). Inability to make a decision raised the likelihood of a do-not-resuscitate (3.7 [2.6-5.4]) than a resuscitate (1.7 [1.2-2.3]) directive (p=0.0005). Within Canada and the USA, cities differed strikingly, as did centres within cities. INTERPRETATION: Cardiopulmonary resuscitation directives established within 24 h of admission to ICU are uncommon. As well as clinical factors, timing and location of admission might determine rate and nature of resuscitation directives.

Incidence of and risk factors for ventilator-associated pneumonia in critically ill patients.

BACKGROUND: Understanding the risk factors for ventilator-associated pneumonia can help to assess prognosis and devise and test preventive strategies. OBJECTIVE: To examine the baseline and time-dependent risk factors for ventilator-associated pneumonia and to determine the conditional probability and cumulative risk over the duration of stay in the intensive care unit. DESIGN: Prospective cohort study. SETTING: 16 intensive care units in Canada. PATIENTS: 1014 mechanically ventilated patients. MEASUREMENTS: Demographic and time-dependent variables reflecting illness severity, ventilation, nutrition, and drug exposure. Pneumonia was classified by using five methods: adjudication committee, bedside clinician's diagnosis, Centers for Disease Control and Prevention definition, Clinical Pulmonary Infection score, and positive culture from bronchoalveolar lavage or protected specimen brush. RESULTS: 177 of 1014 patients (17.5%) developed ventilator-associated pneumonia 9.0 +/- 5.9 days (median, 7 days [interquartile range, 5 to 10 days]) after admission to the intensive care unit. Although the cumulative risk increased over time, the daily hazard rate decreased after day 5 (3.3% at day 5, 2.3% at day 10, and 1.3% at day 15). Independent predictors of ventilator-associated pneumonia in multivariable analysis were a primary admitting diagnosis of burns (risk ratio, 5.09 [95% CI, 1.52 to 17.03]), trauma (risk ratio, 5.00 [CI, 1.91 to 13.11]), central nervous system disease (risk ratio, 3.40 [CI, 1.31 to 8.81]), respiratory disease (risk ratio, 2.79 [CI, 1.04 to 7.51]), cardiac disease (risk ratio, 2.72 [CI, 1.05 to 7.01]), mechanical ventilation in the previous 24 hours (risk ratio, 2.28 [CI, 1.11 to 4.68]), witnessed aspiration (risk ratio, 3.25 [CI, 1.62 to 6.50]), and paralytic agents (risk ratio, 1.57 [CI, 1.03 to 2.39]). Exposure to antibiotics conferred protection (risk ratio, 0.37 [CI, 0.27 to 0.51]). Independent risk factors were the same regardless of the pneumonia definition used. CONCLUSIONS: The daily risk for pneumonia decreases with increasing duration of stay in the intensive care unit. Witnessed aspiration and exposure to paralytic agents are potentially modifiable independent risk factors. Exposure to antibiotics was associated with low rates of early ventilator-associated pneumonia, but this effect attenuates over time.

A comparison of sucralfate and ranitidine for the prevention of upper gastrointestinal bleeding in patients requiring mechanical ventilation. Canadian Critical Care Trials Group.

BACKGROUND: Critically ill patients who require mechanical ventilation are at increased risk for gastrointestinal bleeding from stress ulcers. There are conflicting data on the effect of histamine H2-receptor antagonists and the cytoprotective agent sucralfate on rates of gastrointestinal bleeding, ventilator-associated pneumonia, and mortality. METHODS: In a multicenter, randomized, blinded, placebo-controlled trial, we compared sucralfate with the H2-receptor antagonist ranitidine for the prevention of upper gastrointestinal bleeding in 1200 patients who required mechanical ventilation. Patients received either nasogastric sucralfate suspension (1 g every six hours) and an intravenous placebo or intravenous ranitidine (50 mg every eight hours) and a nasogastric placebo. RESULTS: The patients in the two groups had similar base-line characteristics. Clinically important gastrointestinal bleeding developed in 10 of 596 (1.7 percent) of the patients receiving ranitidine, as compared with 23 of 604 (3.8 percent) of those receiving sucralfate (relative risk, 0.44; 95 percent confidence interval, 0.21 to 0.92; P=0.02). In the ranitidine group, 114 of 596 patients (19.1 percent) had ventilator-associated pneumonia, as compared with 98 of 604 (16.2 percent) in the sucralfate group (relative risk, 1.18; 95 percent confidence interval, 0.92 to 1.51; P=0.19). There was no significant difference between the groups in mortality in the intensive care unit (ICU) (23.5 percent in the ranitidine group and 22.9 percent in the sucralfate group) or the duration of the stay in the ICU (median, nine days in both groups). CONCLUSIONS: Among critically ill patients requiring mechanical ventilation, those receiving ranitidine had a significantly lower rate of clinically important gastrointestinal bleeding than those treated with sucralfate. There were no significant differences in the rates of ventilator-associated pneumonia, the duration of the stay in the ICU, or mortality.

Accuracy of portable chest radiography in the critical care setting. Diagnosis of pneumonia based on quantitative cultures obtained from protected brush catheter.

Sixty-six supine portable chest radiographs done on the day of bronchoscopy in 62 critical care unit patients suspected of having pneumonia were examined in a blinded fashion by two radiologists. Quantitative culture results obtained from protected brush catheter (PBC) specimens were compared with chest radiograph scores. For one observer, the sensitivity of the chest radiograph for predicting the presence of positive culture results was 0.60, specificity was 0.29, overall agreement was 0.41, positive predictive value was 0.34, and negative predictive value was 0.55. For the second observer, the values were as follows: sensitivity, 0.64; specificity, 0.27; overall agreement, 0.41; positive predictive value, 0.35; and negative predictive value, 0.55. The kappa statistic was calculated at 0.27 indicating marginal interobserver reproducibility. We conclude the portable chest radiograph in the critical care setting is not accurate in predicting the presence of pneumonia when the diagnosis is based on quantitative cultures obtained from protected brush catheter specimens.

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

BACKGROUND: 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. METHODS: 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). RESULTS: 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). CONCLUSIONS: 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.

Right phrenic nerve injury in orthotopic liver transplantation.

Right hemidiaphragm paralysis has been previously documented in patients after orthotopic liver transplantation (OLT) and it may contribute to the development of postoperative pulmonary problems. It has been postulated that a crush injury to the right phrenic nerve during OLT is the cause of dysfunction of the right hemidiaphragm. To assess the incidence and effect of right phrenic nerve injury after OLT, we prospectively studied 48 adult liver recipients. Twelve patients who underwent liver resection (LR), in whom the suprahepatic vena cava was not clamped, were used as a comparison group. Diaphragm excursion by ultrasound and pulmonary function were performed preoperatively and postoperatively; transcutaneous phrenic nerve conduction studies were performed postoperatively. Right phrenic nerve injury and hemidiaphragm paralysis occurred in 79% and 38% of the liver recipients but not after LR. Conduction along the right phrenic nerve was absent in 53% and reduced in another 26%. Left phrenic nerve conduction and left hemidiaphragm excursion were normal in both liver recipients and the patients who had LR. Liver recipients with no conduction in the right phrenic nerve had a significantly greater decrease in vital capacity in the supine position (29 +/- 9.8%) compared with those with some conduction (14 +/- 6.9%, P < 0.001). However, neither the time on the ventilator nor the hospital stay was significantly different in the latter two groups. Complete recovery of phrenic nerve conduction and diaphragm function took until nine months in some patients. Right phrenic nerve injury is common after OLT and it is the cause of right hemidiaphragm dysfunction.

Theophylline delays skeletal muscle fatigue during progressive exercise.

In this study, 31P nuclear magnetic resonance spectroscopy (NMRS) was used to examine the effect of theophylline on human forearm muscle metabolism during progressive exercise. Six healthy men (37 +/- 14 yr of age) were assigned to either a control (CTRL) group (n = 3), or a theophylline treatment (THEO) group (n = 3). Each subject performed two dynamic wrist flexion exercise tests to fatigue, with at least 72 h separating each trial. The THEO group repeated the protocol after receiving 300 mg of sustained-release theophylline every 12 h. 31P spectra were acquired every 36 s throughout exercise, and the relative contributions of the phosphate metabolites and pH were determined. Power output at the onset, or threshold of intracellular acidosis (IT), was identified for each subject from changes in phosphocreatine (PCr) metabolism and pH. Power at maximal exercise and at the IT was found to be reproducible in the CTRL group. After theophylline administration, the maximal power attained by the THEO group increased significantly by 19% (p < 0.05), from 2.25 +/- 0.2 to 2.68 +/- 0.15 W. A similar trend occurred in the onset of the IT, which was also prolonged by 19%, from 1.33 +/- 0.18 to 1.58 +/- 0.22 W. Therapeutic concentrations of theophylline significantly increased the endurance of the forearm musculature, apparently by delaying the onset of intracellular metabolic acidosis. These findings suggest an enhancement of oxidative capacity of the muscle.

The prone position improves arterial oxygenation and reduces shunt in oleic-acid-induced acute lung injury.

The arterial oxygen tension (PaO2) may increase when patients with the adult respiratory distress syndrome are turned from supine to prone. We sought to reproduce this observation in dogs with acute lung injury to study the physiologic mechanism by which the improvement in oxygenation might occur. Twenty anesthetized dogs were ventilated with a constant tidal volume (20 ml/kg) of 100% oxygen. Oleic acid (0.09 ml/kg) was injected into the right atrium while rotating the animals through 360 degrees in 4 stages. Animals in Group I (n = 5) remained supine for 10 to 120 min until the supine PaO2 fell below 200 mm Hg. Those in Group II (n = 4) were kept prone during this period. Dogs in Groups I and II were then turned supine or prone every 30 min 5 times. Cardiac output and pulmonary vascular pressures, functional residual capacity (helium dilution), and regional diaphragmatic motion (determined by dorsal and ventral diaphragmatic markers relative to markers on the chest wall seen on lateral chest radiographs taken at FRC and at end-inspiration) were obtained in each position. Eleven dogs were kept supine (Group III, n = 6) or prone (Group IV, n = 5) for 2 h after oleic acid infusion, after which intrapulmonary shunt (Qs/QT) and ventilation-perfusion heterogeneity were measured in the supine and prone positions using the multiple inert gas elimination technique.(ABSTRACT TRUNCATED AT 250 WORDS)