Mechanical ventilation after lung transplantation

Abstract

IntroductionTo explore the hypothesis that early ventilation strategies influence clinical outcomes in lung transplantation, we have examined our routine ventilation practices in terms of tidal volumes (Vt) and inflation pressures.Methods 124 bilateral lung transplants between 2010 and 2013 were retrospectively assigned to low (<6ml/kg), medium (6-8ml/kg) and high (>8ml/kg) Vt groups based on ventilation characteristics during the first 6 hours after surgery. Those same 124 patients were also stratified to low-pressure (<25cm H2O) and high-pressure (≥25cm H2O) groups. ResultsEighty per cent of patients were ventilated using pressure control mode. Low, medium and high tidal volumes were applied to 10%, 43%, and 47% of patients respectively. After correcting for patients requiring extracorporeal support, there was no difference in short to mid-term outcomes among the different Vt groups. Low inflation pressures were applied to 61% of patients, who had a shorter length of ICU stay (5 vs. 12 days; p=0.012), higher FEV1 at 3 months (77.8% vs. 60.3%; p<0.001), and increased 6-month survival rate (95% vs. 77%; p=0.008). ConclusionLow Vt ventilation has not been fully adopted in our practice. Ventilation with higher inflation pressures, but not tidal volumes, were significantly associated with poorer outcomes after lung transplantation.Response to Reviewers: Dear Prof. Lumb, Article ID: JCRC-D-15-00340 -Mechanical ventilation following lung transplantationWe are most grateful to the reviewers for taking the time and care to appraise this manuscript, and for your constructive critique. We have addressed all of the points that were raised and have amended the manuscript accordingly. We feel that your suggestions has significantly improved the original manuscript.Responses to Reviewer #1 Reviewer #1: "The manuscript does not add anything new to the literature. It has been known for a very long time that excessive tidal volume and/or inflation pressures adversely affect patient outcome."Author response: We are grateful that you have taken the time to review our manuscript, although we are disappointed by your conclusions. We have made detailed arguments in both the introduction and discussion that highlight the need for this work within lung transplantation, combined with our unique approach to this clinical problem. Your statement is in direct opposition with the views of the other reviewers, who have helpfully pointed out the potential importance of our study within this field. Your critique also fails to acknowledge the major ongoing debate regarding the special importance of driving pressures, and the relative roles of tidal volumes and pressures in acute lung injury. As a rebuttal, we would respectfully suggest that our manuscript does add to the existing body of knowledge on this topic. As stated in the manuscript, we believe that our manuscript fills an important gap within the literature on VALI by providing new observations on lung ventilation practices in lung transplant recipients, a population that was...

Mechanical ventilation post‐bilateral lung transplantation: A scoping review

“…The timing and number of tidal volume values recorded varied significantly between the studies. The most detailed continuous dataset reported the mean tidal volume over the first 6 h post‐transplant based on hourly measures of tidal volume 15 . This study reported no significant difference in intensive care unit (ICU) length of stay or 6‐month survival between three tidal volume sub‐groups (<6/6–8/>8 mL/kg rPBW).…”

“…There were 3/11 studies that reported the association between tidal volume and PGD grade within the first 72 h 9,10,15 . Two of the studies identified no significant association 9,15 .…”

“…The positive‐end expiratory pressure (PEEP) was reported in 8/11 studies with a range from 5 to 12 cmH 2 O 9–15,18 . The method of PEEP selection was reported in 1/11 studies, which included initial PEEP selection based on a protocol 9 .…”

Roles of electrical impedance tomography in lung transplantation

“…Nevertheless, it has been challenging to determine the optimal PEEP for mechanical ventilation of lung transplant recipients (Diamond and Ahya, 2014). A previous study showed that the low, medium and high tidal volumes had similar effects on short-and medium-term prognoses in lung transplantation recipients (Thakuria et al, 2016). Although a high PEEP level is associated with a high risk of pneumothorax and bronchial anastomotic complications, it is also associated with increased bronchial blood flow.…”

Primary graft dysfunction: pathophysiology to guide new preventive therapies

“…While most lung transplant centers report using low tidal volume ventilation strategies during and after lung transplant surgery, extension of studies of mechanical ventilator management into the early post-operative period may also impact development of PGD. One retrospective single center study in the United Kingdom reported that only approximately half of lung transplant recipients received tidal volumes < 8mL/kg in the first 6 hours after transplant surgery [14]. Use of a specific ventilator management protocol may improve the frequency of low tidal volume ventilation in this peri-operative population.…”