Andres Zorrilla-Vaca

BACKGROUND: Individualisation of positive-end expiratory pressure (PEEP) is an open-lung ventilation strategy associated with better respiratory mechanics. Mechanical power has been associated with lung injury in critical care settings, but the interaction between optimisation of PEEP and mechanical power during one-lung ventilation (OLV) remains poorly understood. OBJECTIVE: This study aimed to determine the effect of individualisation of PEEP on mechanical power during OLV as well as to establish the association between mechanical power and postoperative pulmonary complications after thoracic surgery. DESIGN: This is a post hoc analysis of a multicentre randomised trial. SETTING: Operating rooms. PATIENTS: Thoracic surgery cases requiring OLV. INTERVENTION: Open-lung ventilation strategy (i.e. individualised PEEP titration based on respiratory compliance) versus standard PEEP. Mechanical power and its components were compared between both groups at five different time-points: two-lung ventilation (T0), baseline OLV (T1), 20 min after OLV (T2), end of OLV (T3) and before extubation (T4). MAIN OUTCOME MEASURES: Our primary outcome included a composite of postoperative pulmonary complications within 30 days after surgery. Multivariable mixed-effects logistic regressions were performed to assess associations between various thresholds of mechanical power and postoperative pulmonary complications. RESULTS: A total 1253 patients were included in this analysis, of which 635 received open-lung ventilation, and 618 received conventional ventilation. The median difference in mechanical power was higher in the open-lung ventilation group during OLV than in the control group at T2, T3 and T4: 1.39 [95% confidence interval (CI), 0.91 to 1.86] J min ⁻¹ , 1.27 (95% CI, 0.79 to 1.75) J min ⁻¹ and 2.12 (95% CI, 1.60 to 2.63) J min ⁻¹ , respectively. While the resistive component of mechanical power was associated with postoperative pulmonary complications [odds ratio (OR), 1.07 (95% CI, 1.01 to 1.13) per J min ⁻¹ ], the static component was protective [OR, 0.91 (95% CI, 0.85 to 0.98) per J min ⁻¹ ]. CONCLUSION: Individualisation of PEEP during OLV leads to nonclinically significant higher levels of mechanical power compared with standard PEEP. Each component of mechanical power seems to have different interactions with the occurrence of postoperative pulmonary complications. TRIAL REGISTRATION: NCT03182062

BACKGROUND: Hypoxemia occurs with relative frequency during one-lung ventilation (OLV) despite advances in airway management. Lung perfusion scans are thought to be one of the most accurate methods to predict hypoxemia during OLV, but their complexity and costs are well-known limitations. There is a lack of preoperative stratification models to estimate the risk of intraoperative hypoxemia among patients undergoing thoracic surgery. Our primary objective was to develop a risk stratification model for hypoxemia during OLV based on preoperative clinical variables. METHODS: This is a single-center, retrospective cohort study including 3228 patients who underwent lung resections with OLV from 2017 to 2022, at a tertiary academic health care center in the United States. Vital signs and ventilator settings were retrieved minute by minute. Intraoperative hypoxemia was defined as an episode of oxygen desaturation (Spo ₂ 2 30 kg/m² (8 points), diabetes mellitus (4 points), congestive heart failure (7 points), hypertension (3 points), and right-sided surgery (3 points). The AUC of the model after bootstrap correction was 0.708 (95% CI, 0.676–0.74). Based on the highest Youden index, the optimal score for predicting intraoperative hypoxemia was 13. The risk of hypoxemia increased from 4.7% in the first quartile of scores (0–13 points), to 32% in the third quartile (27–39 points), and 83.3% in the fourth quartile (>39 points). At scores of 20 or greater, the specificity of the model exceeded 90% and reached a positive predictive value of 80%. CONCLUSIONS: The risk of hypoxemia during OLV can be stratified preoperatively using accessible clinical variables. Our risk model is well calibrated but showed moderate discrimination for predicting intraoperative hypoxemia. The accuracy of preoperative models for risk stratification of hypoxemia during OLV should be explored in prospective studies.

Purpose of review: This review aims to provide an updated overview of lung protective strategies in critically ill patients after surgery, focusing on the utility of postoperative open-lung ventilation during the transition from the operating room to the intensive care unit. Recent findings: Mechanically ventilated patients after surgery represent a challenge in the intensive care unit. Different protective strategies have been proposed to minimize the risk of ventilator-induced lung injury (VILI) and facilitate adequate weaning from mechanical ventilation. Fast-track extubation protocols, increasingly standard in the care of critically ill patients postsurgery, have demonstrated improvements in recovery and reductions in acute lung injury, primarily based on retrospective studies. Open-lung ventilation strategies, such as individualization of positive-end expiratory pressure based on driving pressure and postoperative noninvasive ventilation support with high-flow nasal cannula, are becoming standard of care in high-risk surgical patients after major abdominal or thoracic surgeries. Summary: Mechanical ventilation in surgical patients should adhere to lung protective strategies (i.e., individualizing positive end expiratory pressure and prioritize alveolar recruitment) during the transition from the operating room to the intensive care unit.

Introduction: When used as the primary anesthetic, nerve blocks are not billed as separate procedures. In this scenario, the anesthesia start (AStart) time should include the block procedural time. We measured how often AStart time was documented before the nerve block was placed in the preoperative area, and compared cases where a block team performed the nerve block and cases where the intraoperative anesthesia attending supervised the nerve block. We hypothesized that the involvement of a regional anesthesia team would lead to more accurate documentation of AStart. We also estimated the lost revenue due to inaccurate start time documentation. Methods: The study population were patients undergoing surgery with a peripheral nerve block as the primary anesthetic. For this analysis, AStart occurring less than 10 min before the in-operating room time was defined as potentially inaccurate. Lost potential revenue was estimated by taking the difference between the documented time of local anesthetic administration and the documented AStart time. Results: A total of 745 cases were analyzed. Overall, 439 cases (58%) cases were identified as having potentially inaccurate start times. There were higher rates of inaccurate AStart documentation by the block team (316/482, 65.5%) compared with blocks supervised by the in-room anesthesia attendings (123/263, 46.7%, p<0.001). Overall, the estimated loss in billable revenue during the study period was a total of $70 265. Conclusions: The performance of primary regional anesthesia procedure by a block team increased the incidence of inaccurate documentation and uncaptured potential revenue. There is need for education about accurate nerve block documentation for anesthesiologists, especially when separate teams are used.