Asynchronies during mechanical ventilation are associated with mortality

Intensive Care Med. 2015 Apr;41(4):633-41. doi: 10.1007/s00134-015-3692-6. Epub 2015 Feb 19.

Abstract

Purpose: This study aimed to assess the prevalence and time course of asynchronies during mechanical ventilation (MV).

Methods: Prospective, noninterventional observational study of 50 patients admitted to intensive care unit (ICU) beds equipped with Better Care™ software throughout MV. The software distinguished ventilatory modes and detected ineffective inspiratory efforts during expiration (IEE), double-triggering, aborted inspirations, and short and prolonged cycling to compute the asynchrony index (AI) for each hour. We analyzed 7,027 h of MV comprising 8,731,981 breaths.

Results: Asynchronies were detected in all patients and in all ventilator modes. The median AI was 3.41 % [IQR 1.95-5.77]; the most common asynchrony overall and in each mode was IEE [2.38 % (IQR 1.36-3.61)]. Asynchronies were less frequent from 12 pm to 6 am [1.69 % (IQR 0.47-4.78)]. In the hours where more than 90 % of breaths were machine-triggered, the median AI decreased, but asynchronies were still present. When we compared patients with AI > 10 vs AI ≤ 10 %, we found similar reintubation and tracheostomy rates but higher ICU and hospital mortality and a trend toward longer duration of MV in patients with an AI above the cutoff.

Conclusions: Asynchronies are common throughout MV, occurring in all MV modes, and more frequently during the daytime. Further studies should determine whether asynchronies are a marker for or a cause of mortality.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Critical Illness / mortality
  • Critical Illness / therapy*
  • Hospital Mortality
  • Humans
  • Intensive Care Units
  • Prospective Studies
  • Pulmonary Ventilation
  • Respiration, Artificial / adverse effects*
  • Respiration, Artificial / mortality
  • Respiratory Mechanics*
  • Tidal Volume
  • Time Factors