Perioperative methylprednisolone and early pulmonary function after minimally invasive valve surgery under ultra-fast-track cardiac anesthesia: a retrospectively registered randomized dose-comparison trial

This study aimed to evaluate whether methylprednisolone administered after anesthesia induction affects early postoperative pulmonary function in patients undergoing minimally invasive valve surgery under ultra-fast-track cardiac anesthesia (UFTCA). This was a single-center, retrospectively registered, randomized, double-blind, three-arm dose-comparison controlled trial. A total of 65 patients scheduled for elective minimally invasive valve surgery under UFTCA were enrolled and randomly assigned to receive methylprednisolone 4 mg/kg, methylprednisolone 2 mg/kg, or equivalent-volume normal saline. After anesthesia induction and collection of the second blood sample, the assigned study solution was administered intravenously before the initiation of cardiopulmonary bypass. The primary outcomes were early postoperative pulmonary oxygenation indicators, including oxygenation index (OI), respiratory index (RI), and alveolar–arterial oxygen partial pressure difference P(A–a)O2. Postoperative pulmonary complications were analyzed as exploratory clinical outcomes because of the limited number of events. After exclusion of five patients who required conversion to open surgery or a second cardiopulmonary bypass run, 60 patients were included in the final analysis. All patients underwent minimally invasive valve surgery through a right-sided small-incision approach under UFTCA, including aortic valve replacement, mitral valve replacement, or combined aortic and mitral valve replacement. OI decreased after surgery in all groups, reached its lowest level at 1 h after extubation, and then gradually recovered. Compared with the saline control group, the methylprednisolone groups showed more favorable early postoperative oxygenation profiles, with higher OI and lower RI and P(A-a)O 2 at several early postoperative time points. Inflammatory markers were also lower in the methylprednisolone groups at selected time points. Postoperative recovery variables and major observed short-term complications were comparable among the groups. In patients undergoing minimally invasive valve surgery under UFTCA, low-dose methylprednisolone administered after anesthesia induction was associated with more favorable early postoperative pulmonary oxygenation profiles and attenuated inflammatory responses. No apparent increase in observed short-term adverse events was detected. However, clinical pulmonary complication findings should be interpreted cautiously because of the small sample size and limited number of events. This trial was retrospectively registered in the Chinese Clinical Trial Registry (ChiCTR2400084270).