Comparison of the pulmonary dead-space fraction derived from ventilator volumetric capnography and a validated equation in the survival prediction of patients with acute respiratory distress syndrome

Purpose： This prospective observational study aims to evaluate the accuracy of dead-space fraction derived from the ventilator volumetric capnography （volumetric CO2） or a prediction equation to predict the survival of mechanically ventilated patients with acute respiratory distress syndrome （ARDS）. Methods： Consecutive VDJVT measurements were obtained based upon a prediction equation validated by Frankenfield et al for dead-space ventilation fraction： VD/VT = 0.320 ＋ 0.0106 （PaCO2-ETCO2） 4- 0.003 （RR） ＋ 0.0015 （age） in adult patients who had infection-related severe pneumonia and were confirmed as having ARDS. Here PaCO2 is the arterial partial pressure of carbon dioxide in mmHg; ETC02, the end- tidal carbon dioxide measurement in mmHg; RR, respiratory rate per minute; and age in years. Once the patient had intubation, positive end expiratory pressure was adjusted and after Phigh reached a steady state, VD/VT was measured and recorded as the data for the first day. VD/VT measurement was repeated on days 2, 3, 4, 5 and 6. Meanwhile we collected dead-space fraction directly from the ventilator volu- metric CO2 and recorded it as Vd/Vt. We analyzed the changes in VD/VT and Vd/Vt over the f-day period to determine their accuracy in predicting the survival of ARDS patients. Results： Overall, 46 patients with ARD5 met the inclusion criteria and 24 of them died, During the first 6 days of intubation, VD/VT was significantly higher in nonsurvivors on day 4 （0.70 ± 0,01 vs 0.57 ± 0.01 ）, day 5 （0.73 ± 0.01 vs, 0.54 ± 0.01 ）, and day 6 （0.73 ±0,02 vs. 0.54 ± 0.01 ） （all p - 0.000）. Vd/Vt showed no significant difference on days 1-4 but it was much higher in nonsurvivors on day 5 （0.45 ± 0.04 vs. 0.41 ±0.06） and day 6 （0.47 ± 0,05 vs. 0.40 ± 0.03） （both p - 0.008）. VD/VT on the fourth day was more accurate to predict survival than Vd/Vt. The area under the receiver-operating characteristic curve for VD/VT and Vd/Vt in evaluating ARDS patients survival was day 4 （0,974 ± 0.093 vs. 0.701 ± 0.023, p = 0.0024） with the 95% confidence interval being 0.857-0.999 vs, 0.525-0.84L Conclusion： Compared with Vd/Vt derived from ventilator volumetric CO2, VD/VT on day 4 calculated by Frankenfield et al＇s equation can more accurately predict the survival of ARDS patients.

Long-term quality of life after sepsis and predictors of quality of life in survivors with sepsis

Purpose： To evaluate the quality of life among survivors after sepsis in 2 years, comparing with critical patients without sepsis and the general people, analyze the changes and the predictors of quality of life among septic survivors. Methods： This prospective case-control study screened the intensive care unit （ICU） patients in Tianjin Third Central Hospital from January 2014 to October 2017, and the Chinese general population in the previous studies was also included. According to inclusion criteria and exclusion criteria, 306 patients with sepsis were enrolled as the observation group, and another 306 patients without sepsis in 1CU during the same period, whose ages, gender and Charlson Comorbidity Index matched with observation group, were enrolled as the control group. At 3 too, 12 mo, and 24 mo after discharge, the Mos 36-item Short Form Health Survey （SF-36）, the Euroqol-5 dimension （EQ-5D）, and the activities of daily living （ADL） were evaluated in face-to-face for the quality of life among survivors. Results： There were 210 （68.6%） septic patients and 236 （77.1%） non-septic critically ill patients surviving. At 3 months after discharge, the observation and control groups had the similar demographic characteristics （age： 58.8 ± 18.1years vs. 57.5 ±17.6 years, p = 0.542; male： 52.0% vs. 51.4%, p = 0.926）. However, the observation group had higher acute physiology and chronic health evaluation Ⅱ （APACHEⅡ） scores, higher sequential organ failure assessment （SOFA） scores, longer hospital stay, and longer ICU stay than the control group did （p 〈 0.05）. There were no significant differences in the eight dimensions of the SF36 scale, the EQ-5D health utility scores, and the activities of daily life scores between septic survivors and non-septic survivors （p 〉 0.05）. In addition, compared with the quality of life of the Chinese general population （aged 55-64 years）, the quality of life of septic patients were significantly lower at 3 months after discharge （p 〈 0.05）. Comparing the quality of life of the ill patients who had been discharged at 3 mo and 24 mo, the general health improved statistically （p = 0.000） and clinically （score improvement 〉 5 points）. Older age （OR, 1.050; 95% CI, 1.022-1.078, p = 0.000）, female （OR, 3.375; 95% CI, 1.434 -7.941, p = 0.005） and longer mechanical ventilation time （OR, 3.412; 95% CI, 1.413, 8.244, p = 0.006） were the risk factors for the quality of life of septic survivors. Conclusion： The long-term quality of life of septic survivors was similar to that of non-sepsis critically ill survivors. After discharge, the general health of sepsis improved overtime. Age, female and mechanical ventilation time （〉5 days） were the predictors of the quality of life after sepsis.