A new study, published in the February 2022 issue of the Journal of Critical Care found that single abrupt deflation from high PEEP and repeated short deflations from moderate PEEP caused pulmonary edema, impaired oxygenation and increased PVR.
An abrupt lung deflation in rodents results in lung injury through vascular mechanisms. Ventilator disconnections during endo-tracheal suctioning in humans often cause cardio-respiratory instability. Whether repeated disconnections or lung deflations cause lung injury or oedema is not known and was tested here in a porcine large animal model.
Yorkshire pigs (~ 12 weeks) were studied in three series. First, we compared PEEP abruptly deflated from 26 cmH2O or from PEEP 5 cmH2O to zero. Second, pigs were randomly crossed over to receive rapid versus gradual PEEP removal from 20 cmH2O. Third, pigs with relative volume overload, were ventilated with PEEP 15 cmH2O and randomized to repeated ETT disconnections (15 s every 15 min) or no disconnection for 3 h. Hemodynamics, pulmonary variables were monitored, and lung histology and bronchoalveolar lavage were studied.
As compared to PEEP 5 cmH2O, abrupt deflation from PEEP 26 cmH2O increased PVR, lowered oxygenation, and increased lung wet-to-dry ratio. From PEEP 20 cmH2O, gradual versus abrupt deflation mitigated the changes in oxygenation and vascular resistance. From PEEP 15, repeated disconnections in presence of fluid loading led to reduced compliance, lower oxygenation, higher pulmonary artery pressure, higher lung wet-to-dry ratio, higher lung injury score and increased oedema on morphometry, compared to no disconnects.
Single abrupt deflation from high PEEP, and repeated short deflations from moderate PEEP cause pulmonary oedema, impaired oxygenation, and increased PVR, in this large animal model, thus replicating our previous finding from rodents. Rapid deflation may thus be a clinically relevant cause of impaired lung function, which may be attenuated by gradual pressure release.
To learn more about and request a sample of the Flusso By Pass or Flusso TFI from Solutions in Critical Care, call 888-891-1200 or email us to be connected to your local sales representative.
MED Alliance Group is an ISO 13485 certified medical device distributor with more than 350 years of combined medical device sales and distribution experience. Dedicated to meeting the needs of its clinical customers and manufacturing partners, MED Alliance offers cost-effective, customized sales, logistics, and distribution solutions for products found in anesthesia/respiratory, blood/transfusion therapy, EMS/emergency room, interventional radiology/cath lab, iv/vascular, NICU/PICU and pharmacy.