Prognosis of patients requiring prolonged mechanical ventilation is generally perceived to be poor and clinical studies to date have primarily investigated outcomes of patients undergoing short-term ventilation (1-2). In this study, Jubran and colleagues aimed to evaluate survival, muscle function and quality of life in patients who require prolonged ventilation (median 53 days) in a long term acute-care setting (LTACH). The parameters were measured at enrollement, discharge and six and twelve months after discharge; at enrollement patients were also asked to estimate functional status and QOL two weeks before hospitalization.
Interestingly, about 35% of the patients studied were not randomized, because for the most part they were able to be weaned from the ventilation after the first attempt in the LTACH. Of 315 patients included in the study, 52 (16.5%) died before discharge, 115 patients died between discharge and six-month follow-up, 13 died before twelve-month follow-up (cumulative mortality 57.1%). 169 patients (53.7%) from the original cohort were detached from the ventilator at discharge, 94 (29.8%) were still attached (the remaining 16.5% died before discharge). Prognosis of patients requiring prolonged mechanical ventilation was poor for those who remained attached to a ventilator after repeated weaning attempts (survival 16.4% after one year), whilst prognosis of ventilator-detached patients at discharge was comparable to patients who receive short-term ventilation in an ICU (66.9% vs 61.6%).
P_Imax did not change between admission and discharge, increased at six months and remained unchanged at twelve, signifying that ventilator-induced diaphragmatic dysfunction did not ensue during hospitalization; also, P_Imax was not higher in weaning-success vs weaning-failure patients. Surprisingly, when asked at six months after discharge, 84.7% of survivors answered they were willing to undergo ventilation again if deemed necessary.
Limitations: 45% of pre-illness QOL was estimated using surrogates because patients were unable to fill out the questionnaires themselves (with significantly lower function in the surrogate-responder group vs patient-responder group); muscle-strength assessments after discharge were missing for 40% of survivors, mainly due to inability to achieve face to face encounters; the study was mono-centric.
 

Key points

• It appears vital to strive for ventilator-detachment, as the prognosis of ventilator-detached patients at discharge is much better when compared to non-detached patients (66.9% vs 16.4% survival at one year) and similar to patients who undergo short term ventilation in ICU
• Ventilator-induced diaphragmatic dysfunction was not an issue during prolonged ventilation in this study and respiratory muscle strength did not influence weaning
• Improvement in peripheral muscle is imperative to maximize ability to perform daily activities independently
• Most survivors declare they would be willing to endure prolonged ventilation again if necessary

Bibliografia

1. Damuth E, Mitchell JA, Bartock JL, et al. Long-term survival of critically ill patients treated with prolonged mechanical ventilation: a systematic review and meta-analysis. Lancet Respir Med 2015;3:544-53.
2. Jubran A, Grant BJ, Duffner LA, et al. Effect of pressure support vs unassisted breathing through a tracheost-omy collar on weaning duration in patients requiring prolonged mechanical ventilation: a randomized trial. JAMA 2013;309:671-7.