Respiratory compliance related to prognosis in lung transplant patients with extravenous endometrial oxygenation support

Research Design

This retrospective study examined patients who underwent lung transplants at Wuxi People's Hospital at Nanjing Medical University from 2022 to 2023. The inclusion criteria were (1) ages above age, and (2) subjected to a lung transplant with VV-ECMO. The exclusion criteria were (1) lung grafts. (2) Incomplete CRS record. Figure 1 shows the flow diagram of the patients in this study.

This retrospective study was conducted in accordance with the Declaration of Helsinki (revised in 2013) and was approved by the Ethics Committee of the Affiliate Armpit People's Hospital (No. KY24059). Due to the retrospective nature of this study, the need for informed consent was exempt by the committee.

ECMO Strategy

Pre-ECMO assessments are performed by both surgeons and anesthesiologists in accordance with In vitro Life Support Organization (ELSO) guidelines.⁵. If one ventilation is required, the hemodynamics are stable and the percutaneous oxygen saturation (SPO)₂) maintained over 90% and ECMO treatment was not considered. If hemodynamics are stable₂ VV-ECMO support was used continuously at less than 90%. VV-ECMO support was established intraoperatively in all cases where ECMO indications were met.

Peripheral cannula insertion was the preferred method of support in VV-ECMO. The most common site of cannula insertion was the intrafemoral jugular vein, with the tip of the femoral drainage cannula at the inferior Vena right atrial junction and the upper internal jugular vein cannula above the right atrial junction of the upper vein or right atrium. ECMO management and weaning were performed according to ELSO guidelines⁶.

Measurement of CRS

Within 2 hours of admission to the ICU, the patient was placed in supine position without spontaneous breathing. Otherwise, safe doses of sedatives, pain relief, and muscle relaxants were used to prevent natural breathing. The patient received volume controlled ventilation delivered using a square wave flow. Initial parameter settings were twill (VT) at 6 mL/kg of predicted weight (PBW), PBW was 50 + 0.91 × (calculated as height (height) [cm] – 152.4) Male and 45.5 + 0.91×(height [cm] – 152.4) For women, positive exhaust pressure at 5 cmh (PEEP)₂o, respiratory rate (RR) at 12/min. Plateau pressure (PPLAT) was then recorded. CRS was calculated as VT/(PPLAT-PEEP). Ventilator parameters during the non-measurement period were set by the clinician according to the lung protective ventilation strategy and the condition of each patient⁷.

PGD ​​definition

PGD ​​was diagnosed according to the latest recommendations of the ISHLT Working Group⁴. Patients were graded based on the ratio of partial pressure of oxygen (PAO)₂) In some of the oxygen inspired (FIO₂) (P/F ratio) and chest x-rays. PGD ​​grade (0 hours), 24 hours, 48 ​​hours, and 72 hours were rated at index ICU admission. Patients with pulmonary invasion and chest x-ray showing P/F ratio <200 were defined as PGD3, while patients with ECMO were defined as PGD3 with P/F ratio.

Data collection

The following data were collected from medical records of lung transplant patients: age, body mass index (BMI), gender, primary disease, chronic disease, preoperative cardiopulmonary function and laboratory parameters, acute physiology and chronic health assessment II (Apacheii) score, continuous organ failure assessment (SOFA) score, coldischemia time, ecmo parameters, ecmo paramet P/F, and PACO₂ Within 2 hours after surgery. The main result was survival for 90 days after lung transplantation. Secondary outcomes were postoperative ECMO time, postoperative ventilator time, ICU stay, hospitalization, PGD3, serial renal replacement therapy (CRRT), and pneumonia.

Statistical analysis

Continuous variables with normal distributions are presented as mean ± standard deviation and mean ± standard deviation used for group comparisons. Non-normal distribution continuous variables were presented as median (interquartile range), and the Mann-Whitney U test was used for group comparisons. Categorical variables are expressed as numbers (percentages) and analyzed using chi-square tests or Fisher's exact tests. Using receiver operating characteristics (ROC) curve analysis, area under the curve (AUC) values ​​were calculated to assess the predictive ability of CRS against 90-day mortality. Cutoff points were calculated by obtaining the highest YouDen index (sensitivity + specificity -1). Using the Kaplan-Meier method, cumulative curves and mechanical ventilation times for ECMOs between the two groups were plotted. For survival analysis, log-rank tests were used to assess the effects of low CRS. Univariate COX regression was used to investigate the correlation between CRS and 90-day mortality. Statistical analysis was performed using SPSS 25.0, GraphPad Prism 6.0, and R version 4.3.0 using KMSURV, Survival, and Survminer packages. Results with a P value of 2 fish <0.05 were considered statistically significant.