Association of Low Baseline Diaphragm Muscle Mass With Prolonged Mechanical Ventilation and Mortality Among Critically Ill Adults

IMPORTANCE

Low diaphragm muscle mass at the outset of mechanical ventilation may predispose critically ill patients to poor clinical outcomes.

OBJECTIVE

To determine whether lower baseline diaphragm thickness (Tdi) is associated with delayed liberation from mechanical ventilation and complications of acute respiratory failure (reintubation, tracheostomy, prolonged ventilation >14 days, or death in the hospital).

DESIGN, SETTING, AND PARTICIPANTS

Secondary analysis (July 2018 to June 2019) of a prospective cohort study (data collected May 2013 to January 2016). Participants were 193 critically ill adult patients receiving invasive mechanical ventilation at 3 intensive care units in Toronto, Ontario, Canada.

EXPOSURES

Diaphragm thickness was measured by ultrasonography within 36 hours of intubation and then daily. Patients were classified as having low or high diaphragm muscle mass according to the median baseline Tdi.

MAIN OUTCOMES AND MEASURES

The primary outcome was time to liberation from ventilation accounting for the competing risk of death and adjusting for age, body mass index, severity of illness, sepsis, change in Tdi during ventilation, baseline comorbidity, and study center. Secondary outcomes included in-hospital death and complications of acute respiratory failure.

RESULTS

A total of 193 patients were available for analysis; the mean (SD) age was 60 (15) years, 73 (38%) were female, and the median (interquartile range) Sequential Organ Failure Assessment score was 10 (8-13). Median (interquartile range) baseline Tdi was 2.3 (2.0-2.7) mm. In the primary prespecified analysis, baseline Tdi of 2.3 mm or less was associated with delayed liberation from mechanical ventilation (adjusted hazard ratio for liberation, 0.51; 95% CI, 0.36-0.74). Lower baseline Tdi was associated a higher risk of complications of acute respiratory failure (adjusted odds ratio, 1.77; 95% CI, 1.20-2.61 per 0.5-mm decrement) and prolonged weaning (adjusted odds ratio, 2.30; 95% CI, 1.42-3.74). Lower baseline Tdi was also associated with a higher risk of in-hospital death (adjusted odds ratio, 1.47; 95% CI, 1.00-2.16 per 0.5-mm decrement), particularly after discharge from the intensive care unit (adjusted odds ratio, 2.68; 95% CI, 1.35-5.32 per 0.5-mm decrement).

CONCLUSIONS AND RELEVANCE

In this study, low baseline diaphragm muscle mass in critically ill patients was associated with prolonged mechanical ventilation, complications of acute respiratory failure, and an increased risk of death in the hospital.

Human immunodeficiency virus infection in Northern Ireland 1980-1989

To 31st December 1989, 71 persons are known to have attended medical practitioners in Northern Ireland with a diagnosis of Human Immunodeficiency Virus (HIV) infection. Twenty-one of these persons have had the diagnosis of Acquired Immune Deficiency Syndrome (AIDS) and 11 have died. The distribution of reports in the "at risk" categories of homosexual/bisexual males, injecting drug users, heterosexual males and females was significantly different (p less than 0.001) from those reported in the United Kingdom as a whole. Of tests for HIV infection carried out in patients attending the genitourinary medicine department of the Royal Victoria Hospital between 1987-1989, 0.16% have been positive. The prognostic value of the T4 lymphocyte count at presentation for the subsequent development of AIDS was significant (p = 0.0011). The commonest AIDS indicator disease diagnosed was Pneumocystis carinii pneumonia which was seen in seven of the 21 patients (33%).