Causes of Death Among Medical ICU Patients With Pneumonia Due to COVID-19 in a Safety-Net Hospital

We sought to identify the primary causes of death of adult patients admitted to the medical ICU with symptomatic COVID-19 who ultimately suffered in-hospital mortality over the span of three major waves of COVID-19: Wild-type, alpha/epsilon, and delta.

DESIGN

Retrospective single-center cohort study from March 2020 to December 2021.

SETTING

One medical ICU in a 600-bed Tertiary Care Hospital in Los Angeles, CA.

PATIENTS

Adult (n = 306) ICU patients admitted with symptomatic COVID-19 who suffered in-hospital mortality.

INTERVENTIONS

None.

MAIN RESULTS

Of the 306 patients with COVID-19 who died in the hospital, 86.3% were Hispanic/Latino. The leading cause of death was respiratory failure, occurring in 57.8% of patients. There was no significant change in the rate of pulmonary deaths across the three waves of COVID-19 in our study period. The mean time from symptom onset to admission was 6.5 days, with an average hospital length of stay of 18 days. This did not differ between pulmonary and other causes of death. Sepsis was the second most common cause of death at 23.9% with a significant decrease from the wild-type wave to the delta wave. Among patients with sepsis as the cause of death, 22% (n = 16) were associated with fungemia. There was no significant association between steroid administration and cause of death. Lastly, the alpha/epsilon wave from December 2020 to May 2021 had the highest mortality rate when compared with wild-type or delta waves.

CONCLUSIONS

We found the primary cause of death in ICU patients with COVID-19 was acute respiratory failure, without significant changes over the span of three waves of COVID-19. This finding contrasts with reported causes of death for patients with non-COVID-19 acute respiratory distress syndrome, in which respiratory failure is an uncommon cause of death. In addition, we identified a subset of patients (5%) who died primarily due to fungemia, providing an area for further investigation.

Six-minute walk distance in healthy young adults

BACKGROUND

The 6-min walk test (6MWT) is a commonly used clinical assessment of exercise capacity in patients with cardiopulmonary or neuromuscular disease, but normal values are lacking for young adults, who are frequent subjects of testing.

METHODS

In a two-center study, 272 young adults, ages 18-50, underwent American Thoracic Society protocolized 6-min walk testing, and 56 underwent repeat testing. A linear regression model was developed based on anthropomorphic data. This model was compared to existing prediction equations.

RESULTS

Median 6MWD for the cohort was 637 m (IQR 584-686 m) and was not significantly impacted by age. This is in contrast to existing equations extrapolated from older subjects that predict increasing 6MWD in younger subjects. We found weak correlation of 6MWD with height, weight, BMI, and resting heart rate. Heart rate at completion correlated most strongly with 6MWD (rho 0.53 p < 0.0001). Repeat 6MWD was surprisingly variable, with a median difference between tests of 32.5 ± 31.9 m. Established reference equations performed poorly in this population, largely because age has much less effect on 6MWD in this group than in older adults.

CONCLUSIONS

Established reference equations should be reconfigured to include data from young adults, as age has minimal effect on 6MWD in this population. Heart rate response may be a valuable measure of effort in normal subjects. Six-minute walk distance, as with pulmonary function and exercise testing, should have predictive equations across the spectrum of age to allow for accurate assessment of exercise limitation.

Pathologic Difference between Sepsis and Bloodstream Infections

BACKGROUND

Sepsis, defined as life-threatening organ failure caused by a dysregulated host response to infection, is a major cause of morbidity and mortality in hospitalized patients. Understanding the features that distinguish sepsis from bloodstream infections (and other types of infection) can help clinicians appropriately and efficiently target their diagnostic workup and therapeutic interventions, especially early in the disease course.

CONTENT

In this review, sepsis and bloodstream infections are both defined, with a focus on recent changes in the sepsis definition. The molecular and cellular pathways involved in sepsis pathogenesis are described, including cytokines, the coagulation cascade, apoptosis, and mitochondrial dysfunction. Laboratory tests that have been evaluated for their utility in sepsis diagnosis are discussed.

SUMMARY

Sepsis is defined not only by the presence of an infection, but also by organ dysfunction from a dysregulated host response to that infection. Numerous pathways, including proinflammatory and antiinflammatory cytokines, the coagulation cascade, apoptosis, and mitochondrial dysfunction, help determine if a bloodstream infection (or any other infection) progresses to sepsis. Many biomarkers, including C-reactive protein, procalcitonin, and lactic acid have been evaluated for use in sepsis diagnosis, although none are routinely recommended for that purpose in current clinical practice. While some laboratory tests can help distinguish the 2, the presence of organ dysfunction is what separates sepsis from routine infections.

Factors associated with recurrence and mortality in central line-associated bloodstream infections: a retrospective cohort study

Background

Central line-associated bloodstream infections (CLABSIs) are associated with increased mortality, hospital length of stay, and cost. Antimicrobial treatment guidelines for CLABSIs are primarily based on expert opinion. We hypothesized that shorter antimicrobial treatment duration is associated with decreased 60-day recurrence-free survival.

Methods

A retrospective cohort study of all adults with hospital-acquired CLABSIs (HA-CLABSIs) over 5 years at a single tertiary care academic hospital was performed. The time from the end of effective antimicrobial treatment until recurrence of infection or mortality, censored at 60 days after the end of antimicrobial treatment, represented the primary outcome. Effective antimicrobial treatment was defined as the administration of at least one antimicrobial to which the causative organism was sensitive.

Results

A total of 366 cases met eligibility criteria. The median Sequential Organ Failure Assessment (SOFA) score was 6 (interquartile range (IQR) 4–8). Patients were treated for a median of 15 (IQR 10–20) days with effective antimicrobials. The incidence of 60-day mortality or recurrence after completion of the antimicrobial course was 22.1% (81 patients). In a Cox proportional-hazards model, antimicrobial treatment duration (hazard ratio (HR) = 0.35; 95% confidence interval (CI) 0.26–0.48), SOFA score (HR = 1.16; 95% CI 1.09–1.22), and age (HR = 1.021; 95% CI = 1.004–1.037) were associated with mortality or recurrence. The effect of antimicrobial treatment duration appeared to plateau after 15 days.

Conclusions

Longer antimicrobial treatment duration in patients with HA-CLABSIs is associated with improved recurrence-free survival during the first 60 days after infection. This effect appears to plateau after 15 days of treatment. Prospective studies are needed to definitively determine the optimal antimicrobial treatment duration for CLABSIs.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-2206-7) contains supplementary material, which is available to authorized users.

Validation of a Sequential Organ Failure Assessment Score using Electronic Health Record Data

The sequential organ failure assessment (SOFA) score is a scoring system commonly used in critical care to assess severity of illness. Automated calculation of the SOFA score using existing electronic health record data would broaden its applicability. We performed a manual validation of an automated SOFA score previously developed at our institution. A retrospective analysis of a random subset of 300 patients from a previously published randomized trial of critically ill adults was performed, with manual validation of SOFA scores from the date of initial intensive care unit admission. Spearman's rank correlation coefficient, weighted Cohen's kappa, and Bland-Altman plots were used to assess agreement between manual and electronic versions of SOFA scores and between manual and electronic versions of their individual components. There was high agreement between manual and electronic SOFA scores (Spearman's rank correlation coefficient = 0.90, 95% CI 0.87-0.93). Renal and respiratory components had lower agreement (weighted Cohen's kappa = 0.63, 95% CI 0.53-0.73 for renal; weighted Cohen's kappa = 0.77, 95% CI 0.70-0.84 for respiratory). The area under the receiver operating characteristic curve (AUC) for 30-day in-hospital mortality was 0.77 (95% CI 0.68-0.84) for manual SOFA scores and 0.75 (95% CI 0.66-0.83) for automated SOFA scores. Automatic calculation of SOFA scores from the electronic health record is feasible and correlates highly with manually calculated SOFA scores. Both have similar predictive value for 30-day in-hospital mortality.

Randomized Trial of Apneic Oxygenation during Endotracheal Intubation of the Critically Ill

RATIONALE

Hypoxemia is common during endotracheal intubation of critically ill patients and may predispose to cardiac arrest and death. Administration of supplemental oxygen during laryngoscopy (apneic oxygenation) may prevent hypoxemia.

OBJECTIVES

To determine if apneic oxygenation increases the lowest arterial oxygen saturation experienced by patients undergoing endotracheal intubation in the intensive care unit.

METHODS

This was a randomized, open-label, pragmatic trial in which 150 adults undergoing endotracheal intubation in a medical intensive care unit were randomized to receive 15 L/min of 100% oxygen via high-flow nasal cannula during laryngoscopy (apneic oxygenation) or no supplemental oxygen during laryngoscopy (usual care). The primary outcome was lowest arterial oxygen saturation between induction and 2 minutes after completion of endotracheal intubation.

MEASUREMENTS AND MAIN RESULTS

Median lowest arterial oxygen saturation was 92% with apneic oxygenation versus 90% with usual care (95% confidence interval for the difference, -1.6 to 7.4%; P = 0.16). There was no difference between apneic oxygenation and usual care in incidence of oxygen saturation less than 90% (44.7 vs. 47.2%; P = 0.87), oxygen saturation less than 80% (15.8 vs. 25.0%; P = 0.22), or decrease in oxygen saturation greater than 3% (53.9 vs. 55.6%; P = 0.87). Duration of mechanical ventilation, intensive care unit length of stay, and in-hospital mortality were similar between study groups.

CONCLUSIONS

Apneic oxygenation does not seem to increase lowest arterial oxygen saturation during endotracheal intubation of critically ill patients compared with usual care. These findings do not support routine use of apneic oxygenation during endotracheal intubation of critically ill adults. Clinical trial registered with www.clinicaltrials.gov (NCT 02051816).