Prevalence and impact of early prone position on 30-day mortality in mechanically ventilated patients with COVID-19: a nationwide cohort study

 

by Lars Engerström, Johan Thermaenius, Johan Mårtensson, Anders Oldner, Johan Petersson, Jessica Kåhlin and Emma Larsson 

 

Critical Care volume 26, Article number: 264 (2022) 

 

Background

COVID-19 ARDS shares features with non-COVID ARDS but also demonstrates distinct physiological differences. Despite a lack of strong evidence, prone positioning has been advocated as a key therapy for COVID-19 ARDS. The effects of prone position in critically ill patients with COVID-19 are not fully understood, nor is the optimal time of initiation defined. In this nationwide cohort study, we aimed to investigate the association between early initiation of prone position and mortality in mechanically ventilated COVID-19 patients with low oxygenation on ICU admission.

Methods

Using the Swedish Intensive Care Registry (SIR), all Swedish ICU patients ≥ 18 years of age with COVID-19 admitted between March 2020, and April 2021 were identified. A study-population of patients with PaO2/FiO2 ratio ≤ 20 kPa on ICU admission and receiving invasive mechanical ventilation within 24 h from ICU admission was generated. In this study-population, the association between early use of prone position (within 24 h from intubation) and 30-day mortality was estimated using univariate and multivariable logistic regression models.

Results

The total study cohort included 6350 ICU patients with COVID-19, of whom 46.4% were treated with prone position ventilation. Overall, 30-day mortality was 24.3%. In the study-population of 1714 patients with lower admission oxygenation (PaO2/FiO2 ratio ≤ 20 kPa), the utilization of early prone increased from 8.5% in March 2020 to 48.1% in April 2021. The crude 30-day mortality was 27.2% compared to 30.2% in patients not receiving early prone positioning. We found no significant association between early use of prone positioning and survival.

Conclusions

During the first three waves of the COVID-19 pandemic, almost half of the patients in Sweden were treated with prone position ventilation. We found no association between early use of prone positioning and survival in patients on mechanical ventilation with severe hypoxemia on ICU admission. To fully elucidate the effect and timing of prone position ventilation in critically ill patients with COVID-19 further studies are desirable.

 

 

Renin Kinetics Are Superior to Lactate Kinetics for Predicting In-Hospital Mortality in Hypotensive Critically Ill Patients*

 

by Jeyaraju, Maniraj; McCurdy, Michael T.; Levine, Andrea R.; Devarajan, Prasad; Mazzeffi, Michael A.; Mullins, Kristin E.; Reif, Michaella; Yim, David N.; Parrino, Christopher; Lankford, Allison S.; Chow, Jonathan H. 

 

Critical Care Medicine: January 2022 - Volume 50 - Issue 1 - p 50-60

 

Objectives: 

Whole blood lactate concentration is widely used in shock states to assess perfusion. We aimed to determine if the change in plasma renin concentration over time would be superior to the change in lactate concentration for predicting in-hospital mortality in hypotensive patients on vasopressors.

Design: 

Prospective, observational cohort study.

Setting: 

Tertiary academic ICU.

Patients: 

Adult patients on vasopressors for greater than 6 hours to maintain a mean arterial pressure greater than or equal to 65 mm Hg during January 2020.

Interventions: 

Plasma renin concentrations were measured at enrollment and at 24, 48, and 72 hours. Whole blood lactate measurements were performed according to normal standard of care. Logistic regression was performed to evaluate whether the change in renin or lactate concentration could predict in-hospital mortality. Generalized estimating equations were used to analyze the association between renin and lactate concentration and in-hospital mortality. The area under the receiver operating characteristics curve was performed to measure the discriminative ability of initial and peak renin and lactate concentration to predict mortality. The association between renin and lactate concentration above the upper limit of normal at each timepoint with in-hospital mortality was also examined.

Measurements and Main Results: 

The study included 197 renin and 148 lactate samples obtained from 53 patients. The slope of the natural log (ln) of renin concentration was independently associated with mortality (adjusted odds ratio, 10.35; 95% CI, 1.40–76.34; p = 0.022), but the slope of ln-lactate concentration was not (adjusted odds ratio, 4.78; 95% CI, 0.03–772.64; p = 0.55). The generalized estimating equation models found that both ln-renin (adjusted odds ratio, 1.18; 95% CI, 1.02–1.37; p = 0.025) and ln-lactate (adjusted odds ratio, 2.38; 95% CI, 1.05–5.37; p = 0.037) were associated with mortality. Area under the receiver operating characteristics curve analysis demonstrated that initial renin could predict in-hospital mortality with fair discrimination (area under the receiver operating characteristics curve, 0.682; 95% CI, 0.503–0.836; p = 0.05), but initial lactate could not (area under the receiver operating characteristics curve, 0.615; 95% CI, 0.413–0.803; p = 0.27). Peak renin (area under the receiver operating characteristics curve, 0.728; 95% CI, 0.547–0.888; p = 0.01) and peak lactate (area under the receiver operating characteristics curve, 0.746; 95% CI, 0.584–0.876; p = 0.01) demonstrated moderate discrimination. There was no significant difference in discriminative ability between initial or peak renin and lactate concentration. At each study time point, a higher proportion of renin values exceeded the threshold of normal (40 pg/mL) in nonsurvivors than in survivors, but this association was not significant for lactate.

Conclusions: 

Although there was no significant difference in the performance of renin and lactate when examining the absolute values of each laboratory, a positive rate of change in renin concentration, but not lactate concentration, over 72 hours was associated with in-hospital mortality. For each one-unit increase in the slope of ln-renin, the odds of mortality increased 10-fold. Renin levels greater than 40 pg/mL, but not lactate levels greater than 2 mmol/L, were associated with in-hospital mortality. These findings suggest that plasma renin kinetics may be superior to lactate kinetics in predicting mortality of hypotensive, critically ill patients.