Pilot Feasibility Study of Therapeutic Hypothermia for Moderate to Severe Acute Respiratory Distress Syndrome

Abstract

Objectives

Prior studies suggest hypothermia may be beneficial in ARDS, but cooling causes shivering and increases metabolism. The objective of this study was to assess the feasibility of performing a randomized clinical trial (RCT) of hypothermia in patients with ARDS receiving treatment with neuromuscular blockade (NMB) because they cannot shiver.

Design

Retrospective study and pilot prospective open-label feasibility study.

Setting

Medical Intensive Care Unit.

Patients

Retrospective review of 58 patients with ARDS based on Berlin criteria and P _aO2:FiO2 (P:F)<150 who received NMB. Prospective hypothermia treatment in 8 ARDS patients with (P:F)<150 receiving NMB.

Intervention

Cooling to 34°–36°C for 48h.

Measurements and Main Results

Core temperature, hemodynamics, serum glucose and electrolytes, and P:F, were sequentially measured and medians (interquartile ranges) presented, and 28-day ventilator-free days (VFDs), and hospital mortaltiy were calculated in historical controls and 8 cooled patients. Average patient core temperature was 36.7(36–37.3)°C and fever occurred during NMB in 30/58 retrospective patients. In the prospectively cooled patients core temperature reached target range ≤4h of initiating cooling, remained <36°C for 92% of the 48h cooling period without adverse events, and was lower than the controls (34.35(34–34.8)°C; p<0.0001). Compared with historical controls, the cooled patients tended to have lower hospital mortality (75% vs 53.4%; p=0.26), more VFDs (9(0–21.5) vs. 0(0–12); p=0.16) and higher day-3 P:F (255(160–270) vs. 171(120–214), p=0.024).

Conclusions

NMB alone does not cause hypothermia, but allowed ARDS patients to be effectively cooled. Results support conducting an RCT of hypothermia in ARDS and the feasibility of studying ARDS patients receiving NMB.