Date Published: February 11, 2019
Publisher: Public Library of Science
Author(s): Alfonso Wolfango Avolio, Rita Gaspari, Luciana Teofili, Giuseppe Bianco, Giorgia Spinazzola, Paolo Maurizio Soave, Gianfranco Paiano, Alessandra Gioia Francesconi, Andrea Arcangeli, Nicola Nicolotti, Massimo Antonelli, Jose Ignacio Herrero.
Postoperative respiratory failure (PRF, namely mechanical ventilation >48 hours) significantly affects morbidity and mortality in liver transplantation (LTx). Previous studies analyzed only one or two categories of PRF risk factors (preoperative, intraoperative or postoperative ones).
Two classification approaches were used: systematic classification (recipient-related preoperative factors; intraoperative factors; logistic factors; donor factors; postoperative ICU factors; postoperative surgical factors) and patient/organ classification (patient-related general factors; native-liver factors; new-liver factors; kidney factors; heart factors; brain factors; lung factors). Two hundred adult non-acute patients were included. Missing analysis was performed. The competitive role of each factor was assessed.
PRF occurred in 36.0% of cases. Among 28 significant PRF predictors at univariate analysis, 6 were excluded because of collinearity, 22 were investigated by ROC curves and by logistic regression analysis. Recipient age (OR = 1.05; p = 0.010), female sex (OR = 2.75; p = 0.018), Model for End-Stage Liver Disease (MELD, OR = 1.09; p<0.001), restrictive lung pattern (OR = 2.49; p = 0.027), intraoperative veno-venous bypass (VVBP, OR = 3.03; p = 0.008), pre-extubation PaCO2 (OR = 1.11; p = 0.003) and Model for Early Allograft Function (MEAF, OR = 1.37; p<0.001) resulted independent PRF risk factors. As compared to patients without PRF, the PRF-group had longer LoS (10 days IQR 7–18 versus 5 days IQR 4–7, respectively; p<0.001) and lower day-90 survival (86.0% versus 97.6% respectively, p<0.001). In conclusion, MELD, restrictive lung pattern, surgical complexity as captured by VVBP, pre-extubation PaCO2 and MEAF are the main predictors of PRF in non-acute LTx patients.
Postoperative pulmonary complications occur in 5 to 10% of surgical patients, and in 9 to 40% abdominal surgical patients [1–3]. Infectious and non-infectious pulmonary complications are the main cause of early postoperative morbidity, early mortality, and increased hospital stay [1–3]. Postoperative respiratory failure (PRF), defined as the need for mechanical ventilation for more than 48 hours after surgery is among the most serious postoperative pulmonary complications [3–4].
Overall, 212 consecutive transplants performed in 210 adult patients were identified. Twelve transplants were excluded (8 acute liver failure, 1 death at ICU arrival, 1 tracheotomy before LTx, and 2 early re-transplants due to primary non-function of the graft). In total, 200 transplants in 200 patients were studied. (S1 Fig). Among 200 patients, 7 had been previously admitted to the ICU (2 pneumonia, 2 variceal bleeding and 3 sepsis) and discharged before LTx. In contrast, 3 patients requiring hemofiltration were transplanted while staying in ICU. All patients arrived to ICU intubated and mechanically ventilated as per our protocol. Patients’ characteristics of the study population are summarized in Table 2.
The reported incidence of PRF in liver transplantation ranges between 11% and 42% due to the different thresholds used to define “prolonged” mechanical ventilation (from 24 hours to 7.5 days), and to the different inclusion criteria [11–18]. Overall, the incidence of PRF in our study population is 36.0%. We found that PRF is affected by seven independent variables, including MELD at transplant, restrictive lung pattern, use of VVBP, MEAF, pre-extubation PaCO2, patient age and sex. Remarkably, many variables considered in our analysis, such as intraoperative surgical factors (portal thrombosis and porto-caval anastomosis) or logistic risk factors (D-MELD, BAlance of Risk, CIT) have been never investigated, neither collinearity was ruled out in previous studies [6,11–18]. Furthermore, this is the first study including the MEAF in a multivariable prediction model for PRF.
On the whole, our analysis carried out according to the organ-based perspective, lung restrictive pattern, native liver (MELD), surgical complexity, as captured by VVBP, and new liver function (MEAF) are the main determinants for PRF in non-acute LTx patients. Remarkably, donor variables, as evaluated before the transplant, do not always reflect the postoperative donor-related risk, which can be actually established only in the early postoperative days.