Postoperative complications after thoracic surgery in the morbidly obese patient

Surgical Rib Fixation in Obese Patients with Isolated Flail Chest Improves Outcomes: A Matched Cohort Study

BACKGROUND

Obesity is associated with adverse outcomes after major operations. The role of operative rib fixation (RF) in obese patients with flail chest is not clear. The presence of other associated injuries may complicate the interpretation of outcomes. This study compared outcomes after RF to nonoperative management (NOM) in obese patients with isolated flail chest injury.

METHODS

Adult obese patients (BMI > 29.9) with flail chest were identified from the Trauma Quality Improvement Program (TQIP) database (2016-2018). Hospital transfers, death within 72 h, and extrathoracic injuries were excluded. RF patients were propensity score matched (1:2) to similar NOM patients. Multivariate regression identified independent factors predicting adverse outcomes.

RESULTS

Overall, 367 patients with isolated flail chest who underwent RF were matched with 734 in the NOM group. After matching, the mortality rate was significantly lower in the RF group (1.4% vs. 3.7%; p < 0.05). RF had longer HLOS (15.7 days vs. 12.8 days; p < 0.05) and ICU LOS (10.1 days vs. 8.6 days; p < 0.05), shorter ventilator days (9.2 days vs. 11.5 days; p < 0.05), and a higher rate of venous thromboembolism (7.1% vs. 3.5%, p < 0.05). On multivariate analysis, RF was associated with decreased mortality (OR 0.27; p < 0.05). Early RF (≤ 72 h) was associated with shorter ICU stay and mechanical ventilation.

CONCLUSION

RF for isolated flail chest in obese patients is associated with decreased mortality and fewer ventilator days. When performed early, fixation decreases the need for prolonged ventilator use and ICU stay. A more aggressive VTE prophylaxis should be considered in patients undergoing RF.

Comparison of Intra-operative Pressure-Controlled Ventilation and Volume-Controlled Ventilation in Bariatric Surgery: A Prospective Randomized Study

Background: Mechanical ventilation may be particularly challenging in obese patients undergoing laparoscopic bariatric surgery. The present study aimed to compare the effects of pressure-controlled ventilation (PCV) with those of volume-controlled ventilation (VCV) on peripheral tissue oxygenation (PTO), respiratory function, hemodynamic status, and ventilation-related complications in patients undergoing laparoscopic bariatric surgery.

Methods: A total of 100 patients with obesity who underwent gastric plication or sleeve gastrectomy were recruited for the study, and 60 patients (n=32, in group PCV; n=28, in group VCV) were ultimately enrolled. Data on peri-operative PTO (arterial blood gas [ABG] analysis and tissue oxygen saturation [StO₂]) and respiratory functions were recorded for each patient, along with post-operative hemodynamic status, fluid intake, urinary output, Numeric Pain Rating Scale (NPRS) score , and complications.

Results: The two groups were similar in pH, partial pressure of oxygen, partial pressure of carbon dioxide, oxygen saturation, and lactate values at baseline, intra-operative and post-operative periods. The peri-operative StO₂ values were also similar between the two groups at all times. The two groups were identical in terms of preoperative values for respiratory function tests and post-operative hemodynamic status, fluid intake, urinary output, pain scores, and complication rates.

Conclusions: In conclusion, the choice of the mechanical ventilation mode did not appear to influence oxygen delivery, respiratory function, hemodynamic status, post-operative pain, or ventilation-related complications in obese patients undergoing laparoscopic bariatric surgery.

The Role of Obesity in Early and Long-Term Outcomes after Surgical Excision of Lung Oligometastases from Colorectal Cancer

Obesity correlates with better outcomes in many neoplastic conditions. The aim of this study was to assess its role in the prognosis and morbidity of patients submitted to resection of lung oligometastases from colorectal cancer. Seventy-six patients undergoing a first pulmonary metastasectomy were retrospectively included in the study. Seventeen (22.3%) were obese (body mass index (BMI) >30 kg/m²). Assessed outcomes were overall survival, time to recurrence, and incidence of post-operative complications. Median follow-up was 33 months (IQR 16-53). At follow-up, 37 patients (48.6%) died, whereas 39 (51.4%) were alive. A significant difference was found in the 3-year overall survival (obese 80% vs. non-obese 56.8%, p = 0.035). Competing risk analysis shows that the cumulative incidence of recurrence was not different between the two groups. Multivariate analysis reveals that the number of metastases (p = 0.028), post-operative pneumonia (p = 0.042), and DFS (p = 0.007) were significant predictors of death. Competing risk regression shows that no independent risk factor for recurrence has been identified. The complication rate was not different between the two groups (17.6% vs. 13.6%, p = 0.70). Obesity is a positive prognostic factor for survival after pulmonary metastasectomy for colorectal cancer. Overweight patients do not experience more post-operative complications. Our results need to be confirmed by large multicenter studies.

Perioperative lung protective ventilation in obese patients

The perioperative use and relevance of protective ventilation in surgical patients is being increasingly recognized. Obesity poses particular challenges to adequate mechanical ventilation in addition to surgical constraints, primarily by restricted lung mechanics due to excessive adiposity, frequent respiratory comorbidities (i.e. sleep apnea, asthma), and concerns of postoperative respiratory depression and other pulmonary complications. The number of surgical patients with obesity is increasing, and facing these challenges is common in the operating rooms and critical care units worldwide. In this review we summarize the existing literature which supports the following recommendations for the perioperative ventilation in obese patients: (1) the use of protective ventilation with low tidal volumes (approximately 8 mL/kg, calculated based on predicted -not actual- body weight) to avoid volutrauma; (2) a focus on lung recruitment by utilizing PEEP (8–15 cmH₂O) in addition to recruitment maneuvers during the intraoperative period, as well as incentivized deep breathing and noninvasive ventilation early in the postoperative period, to avoid atelectasis, hypoxemia and atelectrauma; and (3) a judicious oxygen use (ideally less than 0.8) to avoid hypoxemia but also possible reabsorption atelectasis. Obesity poses an additional challenge for achieving adequate protective ventilation during one-lung ventilation, but different lung isolation techniques have been adequately performed in obese patients by experienced providers. Postoperative efforts should be directed to avoid hypoventilation, atelectasis and hypoxemia. Further studies are needed to better define optimum protective ventilation strategies and analyze their impact on the perioperative outcomes of surgical patients with obesity.