Intraoperative Ventilation Research Articles

Management of the Expected Difficult Airway with Planned One-Lung Ventilation: A Retrospective Analysis of 44 Cases

Abstract Background Difficult airway management is essential in anesthesia practice. Particular challenges are posed to patients who require intraoperative one-lung ventilation. Specific guidelines for these scenarios have been lacking. The recent update of German guidelines incorporates recommendations for securing the airway in anticipated difficult airway scenarios in patients requiring one-lung ventilation. However, scientific data on this specific topic is rare. Methods A retrospective analysis was conducted on adult patients undergoing thoracic surgery with one-lung ventilation from 2016 to 2021. During these years, the standard of practice has been in line with the now published guidelines. Patients with anticipated difficult airways were identified, and airway management strategies were analyzed. Results Among 3,197 anesthetic procedures, 44 cases involved anticipated difficult airways, primarily due to prior head and neck tumor treatment. Nasal bronchoscopic awake intubation followed by oral reintubation under videolaryngoscopic inspection and the use of bronchial blockers was the standard procedure. No severe complications were recorded, and one-lung ventilation was maintained successfully in all cases. Discussion The study highlights the challenges of managing difficult airways during thoracic surgery. Recommendations align with recent guidelines, emphasizing the importance of tailored approaches. The use of single-lumen tubes with bronchial blockers appears favorable over double-lumen tubes, offering comparable ventilation quality with reduced risks. Conclusion Despite limitations, the study underscores the safety and efficacy of tailored airway management strategies during one-lung ventilation in patients with anticipated difficult airways. The presented approach offers patient safety and practicability. Further multicenter studies are warranted to validate these findings and refine clinical approaches.

Driving pressure during general anesthesia for minimally invasive abdominal surgery (GENERATOR)—study protocol of a randomized clinical trial

BackgroundIntraoperative driving pressure (ΔP) has an independent association with the development of postoperative pulmonary complications (PPCs) in patients receiving ventilation during general anesthesia for major surgery. Ventilation with high intraoperative positive end–expiratory pressure (PEEP) with recruitment maneuvers (RMs) that result in a low ΔP has the potential to prevent PPCs. This trial tests the hypothesis that compared to standard low PEEP without RMs, an individualized high PEEP strategy, titrated to the lowest ΔP, with RMs prevents PPCs in patients receiving intraoperative protective ventilation during anesthesia for minimally invasive abdominal surgery.Methods“DrivinG prEssure duriNg gEneRal AnesThesia fOr minimally invasive abdominal suRgery (GENERATOR)” is an international, multicenter, two–group, patient and outcome–assessor blinded randomized clinical trial. In total, 1806 adult patients scheduled for minimally invasive abdominal surgery and with an increased risk of PPCs based on (i) the ARISCAT risk score for PPCs (≥ 26 points) and/or (ii) a combination of age > 40 years and scheduled surgery lasting > 2 h and planned to receive an intra–arterial catheter for blood pressure monitoring during the surgery will be included. Patients are assigned to either an intraoperative ventilation strategy with individualized high PEEP, titrated to the lowest ΔP, with RMs or one with a standard low PEEP of 5 cm H2O without RMs. The primary outcome is a collapsed composite endpoint of PPCs until postoperative day 5.DiscussionGENERATOR will be the first adequately powered randomized clinical trial to compare the effects of individualized high PEEP with RMs versus standard low PEEP without RMs on the occurrence of PPCs after minimally invasive abdominal surgery. The results of the GENERATOR trial will support anesthesiologists in their decisions regarding PEEP settings during minimally invasive abdominal surgery.Trial registrationGENERATOR is registered at ClinicalTrials.gov (study identifier: NCT06101511) on 26 October 2023.

Positive end-expiratory pressure and emergence preoxygenation after bariatric surgery: A randomised controlled trial on postoperative oxygenation.

Positive end-expiratory pressure (PEEP) is important to increase lung volume and counteract airway closure during anaesthesia, especially in obese patients. However, maintaining PEEP during emergence preoxygenation might increase postoperative atelectasis by allowing susceptible lung areas to be filled with highly absorbable oxygen that gets entrapped when small airways collapse due to the sudden loss of PEEP at extubation. This study aimed to test the hypothesis that withdrawing PEEP just before emergence preoxygenation would better maintain postoperative oxygenation. Prospective, randomised controlled trial. Single centre secondary hospital in Sweden between December 2019 and January 2023. A total of 60 patients, with body mass index between 35 and 50 kg m -2 , undergoing laparoscopic bariatric surgery. Intraoperative ventilation was the same for all patients with a fixed PEEP of 12 or 14 cmH 2 O depending on body mass index. No recruitment manoeuvres were used. After surgery, patients were allocated to maintained PEEP or zero PEEP during emergence preoxygenation. The primary outcome was change in oxygenation from before awakening to 45 min postoperatively as measured by estimated venous admixture calculated from arterial blood gases. Both groups had impaired oxygenation postoperatively; in the group with PEEP maintained during awakening, estimated venous admixture increased by mean 9.1%, and for the group with zero PEEP during awakening, estimated venous admixture increased by mean 10.6%, difference -1.5% (95% confidence interval -4.6 to 1.7%), P = 0.354. Throughout anaesthesia, both groups exhibited low driving pressures and superior oxygenation compared with the awake state. Withdrawing PEEP before emergence preoxygenation, did not alter early postoperative oxygenation in obese patients undergoing laparoscopic bariatric surgery. Intraoperative oxygenation was excellent despite using fixed PEEP and no recruitment manoeuvres, but deteriorated after extubation, indicating a need for future studies aimed at improving the emergence procedure. www.clinicaltrials.gov , NCT04150276. Registration date: 4 November 2019. Principal investigator: Erland Östberg.

Assessment of fluid responsiveness after tidal volume challenge in renal transplant recipients: a nonrandomized prospective interventional study.

When applying lung-protective ventilation, fluid responsiveness cannot be predicted by pulse pressure variation (PPV) or stroke volume variation (SVV). Functional hemodynamic testing may help address this limitation. This study examined whether changes in dynamic indices such as PPV and SVV, induced by tidal volume challenge (TVC), can reliably predict fluid responsiveness in patients undergoing renal transplantation who receive lung-protective ventilation. This nonrandomized interventional study included renal transplant recipients with end-stage renal disease. Patients received ventilation with a 6 mL/kg tidal volume (TV), and the FloTrac system was attached for continuous hemodynamic monitoring. Participants were classified as responders or nonresponders based on whether fluid challenge increased the stroke volume index by more than 10%. The analysis included 36 patients, of whom 19 (52.8%) were responders and 17 (47.2%) were nonresponders. Among responders, the mean ΔPPV6-8 (calculated as PPV at a TV of 8 mL/kg predicted body weight [PBW] minus that at 6 mL/kg PBW) was 3.32±0.75 and ΔSVV6-8 was 2.58±0.77, compared to 0.82±0.53 and 0.70±0.92 for nonresponders, respectively. ΔPPV6-8 exhibited an area under the curve (AUC) of 0.97 (95% confidence interval [CI], 0.93-1.00; P≤0.001), with an optimal cutoff value of 1.5, sensitivity of 94.7%, and specificity of 94.1%. ΔSVV6-8 displayed an AUC of 0.93 (95% CI, 0.84-1.00; P≤0.001) at the same cutoff value of 1.5, with a sensitivity of 94.7% and a specificity of 76.5%. TVC-induced changes in PPV and SVV are predictive of fluid responsiveness in renal transplant recipients who receive intraoperative lung-protective ventilation.

490. THE IMPACT OF ONE-LUNG VENTILATION ON POSTOPERATIVE COMPLICATIONS AFTER IVOR LEWIS ESOPHAGECTOMY

Abstract Background One of the most common issue after Ivor Lewis esophagectomy are pulmonary complications, affecting up to 27% of patients, leading to longer hospital stay and higher healthcare costs. Traditionally, one-lung ventilation (OLV) with a double-lumen tube, is used during the thoracic phase of esophagectomy in order to provide a good surgical view by collapsing the right lung parenchyma. However, OLV has been proven to contribute to negative respiratory outcomes after surgery. On the other hand, a recent metanalysis showed that Two Lung Ventilation (TLV) is feasible throughout the two phases of the procedure, with good clinical, surgical and oncological results. Methods A consecutive series of patients undergoing minimally invasive Ivor Lewis esophagectomy (MIIL) between November 2022 and November 2023 in one high-volume center was retrospectively reviewed. Intraoperative ventilation characteristics were analyzed. Postoperative pulmonary complications were stratified according to Clavien Dindo classification and further divided into mild (<3a) and severe (>3b). Descriptive statistics was used to analyze the study sample. Data was expressed as median and interquartile range (IQR) for non-normally distributed variables and as proportions for binary variables. Categorical variables are expressed as frequencies and analyzed by chi-square (χ2) tests. P-values of < 0.05 defined statistical significance (two-sided). Results Of the 70 patients, 8 were excluded due to lack of data. 62 patients were further stratified into three groups considering the ratio between the durations of OLV and the thoracic phase (OLV/TP): group A less than 25% of OLV/TP, group B more than 25% but less than 75% and group C more than 75%. No difference between the three groups was found in terms of pulmonary complications (χ2=1.6248, p-value=0.4437) whilst patients with a shorter OLV/TP showed a significant reduction in the incidence of severe respiratory complications(χ2= 8.2974, p-value 0.015785, p < 0.05). Conclusion Taking into account the limits of the study (retrospective nature, single center study), our results show that the length of OLV may negatively affect postoperative pulmonary outcomes. These promising results justify the need to conduct a randomized controlled study that would be instrumental in reaching definitive conclusions.

How to Prevent Ventilator-Induced Lung Injury in Intraoperative Mechanical Ventilation? A Randomized Prospective Study.

Intraoperative mechanical ventilation practices can lead to ventilator-induced lung injury (VILI) and postoperative pulmonary complications in healthy lungs. Mechanical power (MP) has been developed as a new concept in reducing the risk of postoperative pulmonary complications as it considers all respiratory mechanics that cause VILI. The most commonly used intraoperative modes are volume control ventilation (VCV) and pressure control ventilation (PCV). In this study, VCV and PCV modes were compared in terms of respiratory mechanics in patients operated in the supine and prone positions. The patients were divided into 4 groups (80 patients), volume control supine and prone, pressure control supine and prone with 20 patients each. MP, respiratory rate, positive end-expiratory pressure, tidal volume, peak pressure, plato pressure, driving pressure, inspiratory time, height, age, gender, body mass index, and predictive body weight data of the patients included in the groups have been obtained from "electronic data pool" with Structured Query Language queries. The supine and prone MP values of the VCV group were statistically significantly lower than the PCV group (P values were 0.010 and 0.001, respectively). Supine and prone MP values of the VCV group were calculated significantly lower than the PCV group. Intraoperative PCV may be considered disadvantageous regarding the risk of VILI in the supine and prone positions.

Dynamic parameters of fluid responsiveness in the operating room : An analysis of intraoperative ventilation framework conditions.

Reliable assessment of fluid responsiveness with pulse pressure variation (PPV) depends on certain ventilation-related preconditions; however, some of these requirements are in contrast with recommendations for protective ventilation. The aim of this study was to evaluate the applicability of PPV in patients undergoing non-cardiac surgery by retrospectively analyzing intraoperative ventilation data. Intraoperative ventilation data from three large medical centers in Germany and Switzerland from January to December 2018 were extracted from electronic patient records and pseudonymized; 10,334 complete data sets were analyzed with respect to the ventilation parameters set as well as demographic and medical data. In 6.3% of the 3398 included anesthesia records, patients were ventilated with mean tidal volumes (mTV) > 8 ml/kg predicted body weight (PBW). These would qualify for PPV-based hemodynamic assessment, but the majority were ventilated with lower mTVs. In patients who underwent abdominal surgery (75.5% of analyzed cases), mTVs > 8 ml/kg PBW were used in 5.5% of cases, which did not differ between laparoscopic (44.9%) and open (55.1%) approaches. Other obstacles to the use of PPV, such as elevated positive end-expiratory pressure (PEEP) or increased respiratory rate, were also identified. Of all the cases 6.0% were ventilated with amTV of > 8 ml/kg PBW and aPEEP of 5-10 cmH2O and 0.3% were ventilated with amTV > 8 ml/kg PBW and aPEEP of > 10 cmH2O. The data suggest that only few patients meet the currently defined TV (of > 8 ml/kg PBW) for assessment of fluid responsiveness using PPV during surgery.

Lung ultrasound score evaluation of the effect of pressure-controlled ventilation volume-guaranteed on patients undergoing laparoscopic-assisted radical gastrectomy.

Laparoscopic-assisted radical gastrectomy (LARG) is the standard treatment for early-stage gastric carcinoma (GC). However, the negative impact of this procedure on respiratory function requires the optimized intraoperative management of patients in terms of ventilation. To investigate the influence of pressure-controlled ventilation volume-guaranteed (PCV-VG) and volume-controlled ventilation (VCV) on blood gas analysis and pulmonary ventilation in patients undergoing LARG for GC based on the lung ultrasound score (LUS). The study included 103 patients with GC undergoing LARG from May 2020 to May 2023, with 52 cases undergoing PCV-VG (research group) and 51 cases undergoing VCV (control group). LUS were recorded at the time of entering the operating room (T0), 20 minutes after anesthesia with endotracheal intubation (T1), 30 minutes after artificial pneumoperitoneum (PP) establishment (T2), and 15 minutes after endotracheal tube removal (T5). For blood gas analysis, arterial partial pressure of oxygen (PaO2) and partial pressure of carbon dioxide (PaCO2) were observed. Peak airway pressure (Ppeak), plateau pressure (Pplat), mean airway pressure (Pmean), and dynamic pulmonary compliance (Cdyn) were recorded at T1 and T2, 1 hour after PP establishment (T3), and at the end of the operation (T4). Postoperative pulmonary complications (PPCs) were recorded. Pre- and postoperative serum interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) were measured by enzyme-linked immunosorbent assay. Compared with those at T0, the whole, anterior, lateral, posterior, upper, lower, left, and right lung LUS of the research group were significantly reduced at T1, T2, and T5; in the control group, the LUS of the whole and partial lung regions (posterior, lower, and right lung) decreased significantly at T2, while at T5, the LUS of the whole and some regions (lateral, lower, and left lung) increased significantly. In comparison with the control group, the whole and regional LUS of the research group were reduced at T1, T2, and T5, with an increase in PaO2, decrease in PaCO2, reduction in Ppeak at T1 to T4, increase in Pmean and Cdyn, and decrease in Pplat at T4, all significant. The research group showed a significantly lower incidence of PPCs than the control group within 3 days postoperatively. Postoperative IL-1β, IL-6, and TNF-α significantly increased in both groups, with even higher levels in the control group. LUS can indicate intraoperative non-uniformity and postural changes in pulmonary ventilation under PCV-VG and VCV. Under the lung protective ventilation strategy, the PCV-VG mode more significantly improved intraoperative lung ventilation in patients undergoing LARG for GC and reduced lung injury-related cytokine production, thereby alleviating lung injury.

Comparative analysis of the effects of bronchial intubation and bronchial blocker on the outcomes of thoracoscopic surgery in infants and small children

Objective: To compare the effects of bronchial intubation and blocker on the outcomes of thoracoscopic surgery in infants and small children. Methods: A total of 387 children, including 210 males and 177 females, aged (17.5±8.3) months, who underwent elective thoracoscopic surgery under general anesthesia in Children's Hospital Affiliated to Capital Institute of Pediatrics from January 2019 to August 2023 were retrospectively analyzed. The children were divided into bronchial intubation group and bronchial blocker group according to the intraoperative single-lung ventilation mode. After matching the age factor using the propensity score matching with nearest neighbor matching method, 258 cases were finally included in the bronchial intubation group, and 129 cases were included in the bronchial blocker group. The primary outcome was the incidence of postoperative pulmonary complications in two groups. The secondary outcomes included the incidence of intraoperative hypoxemia, postoperative oxygenation index, postoperative extubation time, the length of postoperative hospitalization and the total medical expenses during hospitalization between the two groups. Results: The incidence of postoperative pulmonary complications in the bronchial intubation group and bronchial blocker group was 15.5% (40/258) and 12.4% (16/129), the incidence of intraoperative hypoxemia was 20.2% (52/258) and 16.3% (21/129), the postoperative oxygen indexes were 306 (269, 323) and 311 (274, 336) mmHg (1 mmHg=0.133 kPa), the extubation time was (9.2±4.5) and (8.9±4.2) min, the length of postoperative hospitalization was (5.5±0.6) and (5.5±0.5) days and the total medical expenses were (34±6) and (35±6) thousand yuan, with no statistically significant differences between the two groups (all P>0.05). Conclusion: Both bronchial intubation and blocker can be used for one lung ventilation in thoracoscopic surgery for infants and small children, without affecting the postoperative outcomes.

Hydropneumothorax in a non‐small cell lung cancer patient after lobectomy due to surgical stump air leak

Key messageHydropneumothorax following lobectomy or pneumonectomy is relatively uncommon, with an incidence of 1%–5%. It involves air and fluid in the pleural cavity, often due to intraoperative injury, infection, bronchopleural fistula, or mechanical ventilation. Careful management, including drainage and addressing the underlying cause, is essential to prevent serious outcomes.

Effect of the alveolar recruitment maneuver during laparoscopic colorectal surgery on postoperative pulmonary complications: A randomized controlled trial.

Intraoperative lung-protective ventilation, including low tidal volume and positive end-expiratory pressure, reduces postoperative pulmonary complications. However, the effect and specific alveolar recruitment maneuver method are controversial. We investigated whether the intraoperative intermittent recruitment maneuver further reduced postoperative pulmonary complications while using a lung-protective ventilation strategy. Adult patients undergoing elective laparoscopic colorectal surgery were randomly allocated to the recruitment or control groups. Intraoperative ventilation was adjusted to maintain a tidal volume of 6-8 mL kg-1 and positive end-expiratory pressure of 5 cmH2O in both groups. The alveolar recruitment maneuver was applied at three time points (at the start and end of the pneumoperitoneum, and immediately before extubation) by maintaining a continuous pressure of 30 cmH2O for 30 s in the recruitment group. Clinical and radiological evidence of postoperative pulmonary complications was investigated within 7 days postoperatively. A total of 125 patients were included in the analysis. The overall incidence of postoperative pulmonary complications was not significantly different between the recruitment and control groups (28.1% vs. 31.1%, P = 0.711), while the mean ± standard deviation intraoperative peak inspiratory pressure was significantly lower in the recruitment group (10.7 ± 3.2 vs. 13.5 ± 3.0 cmH2O at the time of CO2 gas-out, P < 0.001; 9.8 ± 2.3 vs. 12.5 ± 3.0 cmH2O at the time of recovery, P < 0.001). The alveolar recruitment maneuver with a pressure of 30 cmH2O for 30 s did not further reduce postoperative pulmonary complications when a low tidal volume and 5 cmH2O positive end-expiratory pressure were applied to patients undergoing laparoscopic colorectal surgery and was not associated with any significant adverse events. However, the alveolar recruitment maneuver significantly reduced intraoperative peak inspiratory pressure. Further study is needed to validate the beneficial effect of the alveolar recruitment maneuver in patients at increased risk of postoperative pulmonary complications. Trial registration: Clinicaltrials.gov (NCT03681236).

Adjustment of positive end-expiratory pressure to body mass index during mechanical ventilation in general anesthesia: BodyVent, a randomized controlled trial

BackgroundIn patients requiring general anesthesia, lung-protective ventilation can prevent postoperative pulmonary complications, which are associated with higher morbidity, mortality, and prolonged hospital stay. Application of positive end-expiratory pressure (PEEP) is one component of lung-protective ventilation. The correct strategy for setting adequate PEEP, however, remains controversial. PEEP settings that lead to a lower pressure difference between end-inspiratory plateau pressure and end-expiratory pressure (“driving pressure,” ΔP) may reduce the risk of postoperative pulmonary complications. Preliminary data suggests that the PEEP required to prevent both end-inspiratory overdistension and end-expiratory alveolar collapse, thereby reducing ΔP, correlates positively with the body mass index (BMI) of patients, with PEEP values corresponding to approximately 1/3 of patient’s respective BMI. Thus, we hypothesize that adjusting PEEP according to patient BMI reduces ΔP and may result in less postoperative pulmonary complications.MethodsPatients undergoing general anesthesia and endotracheal intubation with volume-controlled ventilation with a tidal volume of 7 ml per kg predicted body weight will be randomized and assigned to either an intervention group with PEEP adjusted according to BMI or a control group with a standardized PEEP of 5 mbar. Pre- and postoperatively, lung ultrasound will be performed to determine the lung aeration score, and hemodynamic and respiratory vital signs will be recorded for subsequent evaluation. The primary outcome is the difference in ΔP as a surrogate parameter for lung-protective ventilation. Secondary outcomes include change in lung aeration score, intraoperative occurrence of hemodynamic and respiratory events, oxygen requirements and postoperative pulmonary complications.DiscussionThe study results will show whether an intraoperative ventilation strategy with PEEP adjustment based on BMI has the potential of reducing the risk for postoperative pulmonary complications as an easy-to-implement intervention that does not require lengthy ventilator maneuvers nor additional equipment.Trial registrationGerman Clinical Trials Register (DRKS), DRKS00031336. Registered 21st February 2023.Trial statusThe study protocol was approved by the ethics committee of the Christian-Albrechts-Universität Kiel, Germany, on 1st February 2023. Recruitment began in March 2023 and is expected to end in September 2023.

One-lung ventilation with fixed and variable tidal volumes on oxygenation and pulmonary outcomes: A randomized trial

ObjectiveTest the hypothesis that one-lung ventilation with variable tidal volume improves intraoperative oxygenation and reduces postoperative pulmonary complications after lung resection. BackgroundConstant tidal volume and respiratory rate ventilation can lead to atelectasis. Animal and human ARDS studies indicate that oxygenation improves with variable tidal volumes. Since one-lung ventilation shares characteristics with ARDS, we tested the hypothesis that one-lung ventilation with variable tidal volume improves intraoperative oxygenation and reduces postoperative pulmonary complications after lung resection. DesignRandomized trial. SettingOperating rooms and a post-anesthesia care unit. PatientsAdults having elective open or video-assisted thoracoscopic lung resection surgery with general anesthesia were randomly assigned to intraoperative ventilation with fixed (n = 70) or with variable (n = 70) tidal volumes. InterventionsPatients assigned to fixed ventilation had a tidal volume of 6 ml/kgPBW, whereas those assigned to variable ventilation had tidal volumes ranging from 6 ml/kg PBW ± 33% which varied randomly at 5-min intervals. MeasurementsThe primary outcome was intraoperative oxygenation; secondary outcomes were postoperative pulmonary complications, mortality within 90 days of surgery, heart rate, and SpO2/FiO2 ratio. ResultsData from 128 patients were analyzed with 65 assigned to fixed-tidal volume ventilation and 63 to variable-tidal volume ventilation. The time-weighted average PaO2 during one-lung ventilation was 176 (86) mmHg in patients ventilated with fixed-tidal volume and 147 (72) mmHg in the patients ventilated with variable-tidal volume, a difference that was statistically significant (p < 0.01) but less than our pre-defined clinically meaningful threshold of 50 mmHg. At least one composite complication occurred in 11 (17%) of patients ventilated with variable-tidal volume and in 17 (26%) of patients assigned to fixed-tidal volume ventilation, with a relative risk of 0.67 (95% CI 0.34–1.31, p = 0.24). Atelectasis in the ventilated lung was less common with variable-tidal volumes (4.7%) than fixed-tidal volumes (20%) in the initial three postoperative days, with a relative risk of 0.24 (95% CI 0.01–0.8, p = 0.02), but there were no significant late postoperative differences. No other secondary outcomes were both statistically significant and clinically meaningful. ConclusionOne-lung ventilation with variable tidal volume does not meaningfully improve intraoperative oxygenation, and does not reduce postoperative pulmonary complications.

Progress in the relationship between mechanical ventilation parameters and ventilator-related complications during perioperative anesthesia.

Mechanical ventilation, as an important respiratory support, plays an important role in general anesthesia and it is the cornerstone of intraoperative management of surgical patients. Different from spontaneous respiration, intraoperative mechanical ventilation can lead to postoperative lung injury, and its impact on surgical mortality cannot be ignored. Postoperative lung injury increases hospital stay and is related to preoperative conditions, anesthesia time, and intraoperative ventilation settings. Through reading literature and research reports, the relationship between perioperative input parameters and output parameters related to mechanical ventilation and ventilator-related complications was reviewed, providing reference for the subsequent setting of input parameters of mechanical ventilation and new ventilation strategies. The parameters of inspiratory pressure rise time and inspiratory time can change the gas distribution, gas flow rate and airway pressure into the lungs, but there are few clinical studies on them. It can be used as a prospective intervention to study the effect of specific protective ventilation strategies on pulmonary complications after perioperative anesthesia. There are many factors affecting lung function after perioperative mechanical ventilation. Due to the difference of human body, the ventilation parameters suitable for each patient are different, and the deviation of each ventilation parameter can lead to postoperative pulmonary complications. Inspiratory pressure rise time and inspiratory time will be used as the new ventilation strategy.

Intraoperative mechanical power and postoperative pulmonary complications in low-risk surgical patients: a prospective observational cohort study

BackgroundInadequate intraoperative mechanical ventilation (MV) can lead to ventilator-induced lung injury and increased risk for postoperative pulmonary complications (PPCs). Mechanical power (MP) was shown to be a valuable indicator for MV outcomes in critical care patients. The aim of this study is to assess the association between intraoperative MP in low-risk surgical patients undergoing general anesthesia and PPCs.MethodsTwo-hundred eighteen low-risk surgical patients undergoing general anesthesia for elective surgery were included in the study. Intraoperative mechanical ventilatory support parameters were collected for all patients. Postoperatively, patients were followed throughout their hospital stay and up to seven days post discharge for the occurrence of any PPCs.ResultsOut of 218 patients, 35% exhibited PPCs. The average body mass index, tidal volume per ideal body weight, peak inspiratory pressure, and MP were significantly higher in the patients with PPCs than in the patients without PPCs (30.3 ± 8.1 kg/m2 vs. 26.8 ± 4.9 kg.m2, p < 0.001; 9.1 ± 1.9 ml/kg vs. 8.6 ± 1.4 ml/kg, p = 0.02; 20 ± 4.9 cmH2O vs. 18 ± 3.7 cmH2O, p = 0.001; 12.9 ± 4.5 J/min vs. 11.1 ± 3.7 J/min, p = 0.002). A multivariable regression analysis revealed MP as the sole significant predictor for the risk of postoperative pulmonary complications [OR 1.1 (95% CI 1.0–1.2, p = 0.036].ConclusionsHigh intraoperative mechanical power is a risk factor for developing postoperative pulmonary complications. Furthermore, intraoperative mechanical power is superior to other traditional mechanical ventilation variables in identifying surgical patients who are at risk for developing postoperative pulmonary complications.Clinical trial registration NCT03551899; 24/02/2017.

Oxygen-Associated Hypercapnia after both side Video-Assisted Thoracoscopic Surgery – A Case Report

Thoracoscopy, as a minimally invasive surgical technique in the field of thoracic surgery, has been widely utilized due to its minimally invasive nature, cost-effectiveness, and short hospital stay. Most thoracoscopic surgeries involve intraoperative single-lung ventilation, aiming to maintain intraoperative oxygen saturation (SPO2) above 93% by increasing the respiratory rate and administering a high concentration of oxygen. However, the high concentration of oxygen administered during surgery and postoperative pain in thoracic surgery often result in decreased ventilation and hypoxia in patients. This case report details a patient who underwent bilateral thoracoscopic surgery with single-lung ventilation on both sides, subsequently developing oxygen-associated hypercapnia in the post-anesthesia care unit (PACU) and necessitating reintubation.

The ventilation efficacy and safety of new nasopharyngeal airway applied in left atrial appendage occlusion

Objective: The present retrospective study aimed to analyses the ventilation efficacy and safety of new nasopharyngeal airway applied in left atrial appendage occlusion. Methods: A total of 37 advanced aged patients diagnosed with atrial fibrillation(>65 years)who underwent left atrial appendage occlusion (LAAO) in Xuanwu Hospital of Capital Medical University from March 2021 to March 2022 were enrolled in this study. All patients received supplemental oxygen by a new nasopharyngeal airway to ensure intraoperative ventilation. The primary outcome was the occurrence of hypoxemia. The secondary outcomes included the incidence of hypotension after anesthesia, the incidence of body movement during surgery, significant fluctuations of the vital signs such as mean arterial pressure (MAP), heart rate (HR), saturation of pulse oxygen (SpO2) and respiratory rate (RR) at different time points (T1: pre-operation; T2: at the time of placing nasopharyngeal airway; T3: at the time of placing transesophageal echocardiography(TEE); T4: at the time of TEE intraoperative exploration; T5: end of the surgery; T6: at the time of patient woke up), and the incidence of postoperative adverse events. Results: There were 24 males and 13 females with a mean age of (73.8±7.7) years. The incidence of hypoxemia was 16.2% (6/37), which could return to normal after simple treatment. The incidence of hypotension was 27.0% (10/37), occurred after anesthesia induction mainly.32.4% (12/37) of the patients experienced movements, but no adverse events led to surgical termination. MAP at different time points was significantly different (P=0.001), but other vital signs of HR, SpO2 and RR were not significantly different(all P>0.05), without serious hemodynamic fluctuations. The incidence of postoperative adverse cardiovascular events was 10.8% (4/37), and delirium was 2.7% (1/37). All patients successfully completed the surgery and were safely discharged from the hospital. Conclusion: The new nasopharyngeal airway can meet the requirements of airway management during left atrial appendage occlusion under intravenous anesthesia without serious adverse events.

Ultrasound-Assisted Neuraxial Anaesthesia and Intra-Operative Non-Invasive Ventilation for Emergency Caesarean Section in a Parturient with Profound Respiratory Failure: A Case Report

Here we describe the perioperative management of a patient with profound respiratory failure. A 32-year-old parturient presented with acute-on-chronic respiratory failure at 30 weeks’ gestation. Her deterioration was attributed to advancing gestation on a background of significant respiratory comorbidity and required emergency caesarean section. Anaesthesia for a safe operative delivery was predicted to be difficult, carrying significant risk for both patient and fetus. We describe the successful use of intra-operative non-invasive ventilation and ultrasound-assisted neuraxial anaesthesia in order to facilitate emergency caesarean section without general anaesthesia.

Severe perioperative lactic acidosis in a pediatric patient with glycogen storage disease type Ia: a case report

BackgroundGlycogen storage disease (GSD) is a group of rare inherited metabolic disorders caused by enzyme deficiencies in glycogen catabolism. GSD type Ia is a congenital deficiency of the enzyme responsible for the final step in glucose production by glycolysis, resulting in impaired carbohydrate metabolism.Case presentationA 14-year-old boy with GSD type Ia was scheduled for a maxillary cystectomy under general anesthesia. He was taking oral sugars such as uncooked cornstarch regularly to prevent hypoglycemia. Perioperatively, glucose was administered via the peripheral vein for fasting; however, severe lactic acidosis occurred. He also developed hypercapnia because of intraoperative poor ventilation caused by hepatomegaly.ConclusionsWe experienced a child with GSD type Ia who developed severe lactic acidosis despite continuous glucose infusion. Further studies are required to determine appropriate perioperative management for patients with GSD, including fasting glucose administration.

Carbon dioxide gas-induced pneumothorax versus one-lung ventilation in minimally invasive esophagectomy: a multicenter propensity score matching cohort study.

Carbon dioxide gas-induced pneumoperitoneum might be the reason for the shorter postoperative survival of patients with malignant tumors. Whether CO 2 gas-induced pneumothorax has unfavorable impacts on the surgical and oncological outcomes of minimally invasive esophagectomy remains unclear. Between 2010 and 2016, a total of 998 patients with squamous cell carcinoma of the esophagus who received video-assisted surgery were registered from three large-volume medical centers. The overall survival (OS) and disease-free survival (DFS) were compared after using propensity score-matched and inverse probability-weighted methods. In addition, the tumor-relapse state was evaluated, and the relapse pattern was compared. A total of 422 and 576 minimally invasive esophagectomies with intraoperative one-lung ventilation and CO 2 -induced pneumothorax were enrolled, respectively. The 5-year OS and DFS were similar between the CO 2 -induced pneumothorax (64.2% and 64.7%) and one-lung ventilation (65.3% and 62.4%) groups following propensity matching. The inverse probability weighting revealed similarly equal survival results in the two groups. The 5-year relapse rates were 35.1% and 30.6% in the one-lung ventilation and CO 2 -induced pneumothorax groups, respectively. Moreover, the relapse patterns were not significantly different between the two groups. The results of this study suggested that the use of intraoperative one-lung ventilation and CO 2 -induced pneumothorax have similar oncological outcomes; therefore, the two methods are both viable options in esophagectomy.