Adaptive support ventilation versus synchronized intermittent mandatory ventilation with pressure support in weaning patients after orthotopic liver transplantation.

BACKGROUND: The extubation phase is an extremely critical moment in patients who have undergone orthotopic liver transplantation, who do not always have the advantage of long-lasting positive-pressure ventilation and positive expiratory end pressure; these factors can lead to splanchnic venous congestion, and this is why a rapid extubation can represent a great benefit for the graft. METHODS: The aim of this study was to compare the adaptive support ventilation (ASV) mode with the standard mode of weaning in our intensive care unit, synchronized intermittent mandatory ventilation with pressure support (P-SIMV), in patients who received orthotopic liver transplantation. ASV is a positive-pressure mode, in which pressure level and respiratory rate are automatically adjusted according to measured lung dynamics at each breath. Eligible patients were assigned to either ASV or P-SIMV group. The weaning protocol was based on the individual respiratory activity and structured in 4 different phases. RESULTS: The average length of intubation was significantly shorter in the ASV group than in the P-SIMV group (90±13 vs 153±22 minutes, P=.05). The total modifications to the ventilator settings were significantly larger in the P-SIMV group (1.5±1 vs 6±2; P=.003). CONCLUSIONS: Our results suggest that although both procedures are safe and easy to apply, ASV is superior in terms of weaning times, and it simplifies respiratory management. The better patient-machine interaction in ASV has been highlighted by other authors for different clusters of patients.

Low-flow venovenous CO2 removal in association with lung protective ventilation strategy in patients who develop severe progressive respiratory acidosis after lung transplantation.

BACKGROUND: Primary graft dysfunction (PGD) might occur after lung transplantation. In some severe cases, conventional therapies like ventilatory support, administration of inhaled nitric oxide (iNO), and intravenous prostacyclins are not sufficient to provide an adequate gas exchange. The aim of our study was to evaluate the use of a lung protective ventilation strategy associated with a low-flow venovenous CO2 removal treatment to reduce ventilator-associated injury in patients that develop severe PGD after lung transplantation. METHODS: From January 2009 to January 2011, 3 patients developed PGD within 24 hours after lung transplantation. In addition to conventional medical treatment, including hemodynamic support, iNO and prostaglandin E1 (PGE1), we initiated a ventilatory protective strategy associated with low-flow venovenous CO2 removal treatment (LFVVECCO2R). Hemodynamic and respiratory parameters were assessed at baseline as well as after 3, 12, 24, and 48 hours. RESULTS: No adverse events were registered. Despite decreased baseline elevated pulmonary positive pressures, application of a protective ventilation strategy with LFVVECCO2R reduced PaCO2 and pulmonary infiltrates as well as increased pH values and PaO2/FiO2 ratios. Every patient showed simultaneous improvement of clinical and hemodynamic conditions. They were weaned from mechanical ventilation and extubated after 24 hours after the use of the low-flow venovenous CO2 removal device. CONCLUSION: The use of LFVVECCO2R together with a protective lung ventilation strategy during the perioperative period of lung transplantation may be a valid clinical strategy for patients with PGD and severe respiratory acidosis occured despite adequate mechanical ventilation.