Scientific Papers

Total intravenous anesthesia decreases hospital stay but not incidence of postoperative pulmonary complications after lung resection surgery: a propensity score matching study | BMC Anesthesiology

Study design and patient selection

This was a retrospective cohort study conducted to find out the association between different anesthetic regimens and the incidence of PPCs in patients who underwent LRS. This study was approved by the Taipei Veterans General Hospital Institutional Review Board (IRB-TPEVGH no.: 2021-03-003CC). The review board waived the need for patient consent. All methods were conducted according to the local guidelines and regulations of Taipei Veterans General Hospital.

We reviewed the electronic medical database of our institution and extracted the data of all patients who underwent video-assisted thoracoscopic surgery (VATS) at our medical center between January 2016 and December 2020. Patients who met the following criteria were excluded from the analysis: [1] missing relevant data, such as demographic information, surgical and anesthetic features, or postoperative outcomes; [2] did not undergo LRS; [3] underwent thoracotomy or intraoperative conversion to open resection; [4] underwent tubeless surgery; [5] underwent delayed extubation; and [6] an American Society of Anesthesiologists (ASA) class four or higher pre-anesthesia health status. The included patients were categorized in two groups: the TIVA group, which comprised patients who received intravenous anesthetics for the maintenance of general anesthesia, and the volatile anesthesia group, which included those who received volatile anesthetics for the maintenance of general anesthesia.

Anesthesia management

Bispectral index (BIS) (Medtronic, Minneapolis, MN) monitoring and hemodynamic monitoring with electrocardiography, pulse oximetry, and noninvasive and invasive arterial blood pressure measurements were routinely performed for the evaluation of patients in both groups. In the volatile anesthesia group, 1–3 ug of fentanyl per kilogram of body weight and 1-2.5 mg of 1% propofol per kilogram of body weight were administered for induction of general anesthesia. Volatile anesthetics, such as sevoflurane or desflurane, were used for maintenance of anesthesia. In the TIVA group, propofol and remifentanil were continuously infused using a target-controlled infusion system based on the Schnider and Minto models, respectively. The doses of anesthetics were adjusted to maintain the BIS between 40 and 60. The intercostal block with 3–5 mL 0.5% bupivacaine for each level was performed by the surgeon in the end of the surgery. Parecoxib 40 mg was administrated every 12 h from the beginning of the surgery to the 24–48 h after surgery and Ultracet tablets was used for rescue analgesia.

Data collection

We extracted the following data from patients’ records: age, sex, height, weight, ASA class, preoperative ratio of the forced expiratory volume in the first one second to the forced vital capacity of the lungs (FEV1/FVC) [6], and underlying disease (myocardial infarction, congestive heart failure, peripheral vascular disease, cerebrovascular accident or transient ischemic attack, dementia, chronic obstructive pulmonary disease, connective tissue disease, peptic ulcer disease, liver disease, diabetes mellitus, hemiplegia, chronic kidney disease, solid tumor, lymphoma, leukemia, acquired immune deficiency syndrome) assessed using Charlson comorbidity index (supplementary file 1) [8]. Intraoperative data, such as anesthesia regimens, anesthesia time were recorded. Postoperative events, such as PPCs (respiratory failure, respiratory infection, atelectasis, pneumothorax, bronchospasm, pleural effusion, upper airway obstruction, prolonged air leakage, pulmonary embolism,) [3, 6, 9], subcutaneous emphysema, chylothorax, re-operation, reintubation, LOS, 30-day unplanned readmission, and postoperative nausea and vomiting (PONV), were recorded as well. PONV was defined as any nausea or vomiting occurring during the first 24 to 48 h after the surgery [10]. The primary outcome was the difference in the incidence of PPCs between the TIVA and volatile anesthetic groups. The secondary outcomes were the differences in the incidences of other postoperative events (subcutaneous emphysema, chylothorax, re-operation, reintubation, LOS, 30-day unplanned readmission, and PONV) between the two groups.

Statistical analysis

Comparisons of the baseline characteristics of the patients in the volatile anesthesia and TIVA groups were performed using the independent t-test or Wilcoxon rank-sum test for continuous variables and the chi-square test for categorical variables, as appropriate. To eliminate imbalances in the collected covariates of two groups, propensity score matching (PSM) was performed with 1:1 nearest neighbor matching method and caliper value of 0.1(supplementary file 2). The covariates included age, height, weight, gender, ASA classification, FEV1/FVC ratio, CCI, anesthesia time and blood loss. Statistical significance was set at P < 0.05 (two-tailed). Based on the previous study by Lee et al. [9], we estimated the minimum requirement of sample size was 264 to achieve a power of 0.8 given a type I error rate of 0.05 [11]. To compare the difference between two groups by the time until discharge, we performed the Cox regression analysis after confirming the proportional hazard assumption. The postoperative deaths were excluded from the analysis. All statistical analyses were performed using Statistical Package for the Social Sciences (SPSS) 28.0 (IBM Corp., Armonk, NY, USA) software.

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