Mortality in patients with respiratory distress syndrome. / Mortalidad en pacientes con síndrome de distress respiratorio.

INTRODUCTION: Mortality in Acute Respiratory Distress Syndrome (ARDS) is decreasing, although its prognosis after hospital discharge and the prognostic accuracy of Berlin's new ARDS stratification are uncertain. METHODS: We did a restrospective analysis of hospital and 6 month mortality of patients with ARDS admitted to the Intensive Care Unit of a Univeristy Hospital in Buenos Aires, between January 2008 and June 2011. ARDS was defined by PaO2/FiO2 lower than 200 mmHg under ventilation with at least 10 cm H2O of PEEP and a FiO2 higher or equal than 0.5. and the presence of bilateral infiltrates in chest radiography, in the absence of cardiogenic acute pulmonary edema, during the first 72 hs of mechanical ventilation. Mortality associated risk factors, the use of rescue therapies and Berlin's stratification for moderate and severe ARDS patients were considered. RESULTS: Ninety eight patients were included; mean age was 59±19 years old, 42,9% had mayor co-morbidities; APACHE II at admission was 22±7; SOFA at day 1 was 8±3. Prone position ventilation was applied in 20,4% and rescue measures in 12,2% (12 patients with nitric oxide and 1 with extracorporeal membrane oxygenation). Hospital and 6 months mortality were 37.7 and 43.8% respectively. After logistic regression analysis, only age, the presence of septic shock at admission, Ppl >30 cmH2O, and major co-morbidities were independently associated with hospital outcome. There was no difference between moderate and severe groups (41,2 and 36,8% respectively; p=0,25). CONCLUSION: In this cohort, including patients with severe hypoxemia and high percentage of mayor co-morbidities, ARDS associated mortality was lower than some previous studies. There was no increase in mortality after hospital discharge. There was no difference in mortality between moderate and severe groups according to Berlin's definition.

Impact of the humidification device on intubation rate during noninvasive ventilation with ICU ventilators: results of a multicenter randomized controlled trial.

PURPOSE: The use of heat and moisture exchangers (HME) during noninvasive ventilation (NIV) can increase the work of breathing, decrease alveolar ventilation, and deliver less humidity in comparison with heated humidifiers (HH). We tested the hypothesis that the use of HH during NIV with ICU ventilators for patients with acute respiratory failure would decrease the rate of intubation (primary endpoint) as compared with HME. METHODS: We conducted a multicenter randomized controlled study in 15 centers. After stratification by center and type of respiratory failure (hypoxemic or hypercapnic), eligible patients were randomized to receive NIV with HH or HME. RESULTS: Of the 247 patients included, 128 patients were allocated to the HME group and 119 to the HH group. Patients were comparable at baseline. The intubation rate was not significantly different: 29.7% in the HME group and 36.9% in the HH group (p = 0.28). PaCO2 did not significantly differ between the two arms, even in the subgroup of hypercapnic patients. No significant difference was observed for NIV duration, ICU and hospital LOS, or ICU mortality (HME 14.1 vs. HH 21.5%, p = 0.18). CONCLUSIONS: In this study, the short-term physiological benefits of HH in comparison with HME during NIV with ICU ventilators were not observed, and no difference in intubation rate was found. The physiologic effects may have been obscured by leaks or other important factors in the clinical settings. This study does not support the recent recommendation favoring the use of HH during NIV with ICU ventilators.

Accuracy of weight and height estimation in an intensive care unit.

We report the findings from a prospective study determining the magnitude of errors in the visual estimation of weight and height of critically ill patients. Forty-two consecutive patients were weighed by a physician with a calibrated stretcher scale and length measured with a steel measuring tape. The predicted body weight was calculated using the ARDSnet formulae. Attending physicians and nurses were asked to estimate patient's actual weight, predicted weight and height. The average percent errors in estimation of actual and predicted weight were 11.4 and 14.6%, respectively. Errors greater than 20% in patient's actual and predicted weight were observed in 15 and 24% of cases, respectively. The majority of height estimations (86%) had an error < 10%. There were non-significant differences between the estimations made by intensive care unit physicians and nurses. Our study shows that estimations of patient's weight made by intensive care unit staff are often inaccurate. In contrast, estimations of height made by intensive care unit staff are usually adequate. Estimated body weight of critically ill patients has implications for drug and respiratory therapy and should be used with caution.