One-lung Ventilation Research Articles

Evaluation of feasibility and safety of non-intubated anesthesia video-assisted thoracoscopic thymectomy for myasthenia gravis

Video-assisted thoracoscopic surgery (VATS) thymectomy is a well-established treatment for Myasthenia gravis (MG). However, traditional VATS thymectomy uses general anesthesia with endotracheal intubation, which can worsen MG symptoms. This study evaluated the feasibility and safety of non-intubated anesthesia VATS for patients with MG to solve this issue. It was a prospective, descriptive study involving six patients aged 18 to 60, ASA I, II, who underwent VATS thymectomy under non-intubated anesthesia and local anesthesia at Vietduc University Hospital between May 2022 and December 2023. The induction time was short, ranging from 3 to 4.5 minutes. The median of Peak PaCO2 and EtCO2 were 42.5 mmHg (range 33-49 mmHg) and 46.4 mmHg (range 44-48 mmHg), respectively. The median values of PaO2 and SpO2 during one-lung ventilation were 161.1 mmHg (range 82-206.9 mmHg) and 98% (range 93-99%). The lungs collapsed well, and breathing and circulation remained stable. No complicationarose, and all patients recovered well. These initial findings suggest that non-intubated anesthesia is a safe and straightforward option for MG thymectomy

The feasibility and accuracy of the method for selecting the optimal size of double-lumen tube in thoracic surgery: a prospective, randomized controlled trial

Double-lumen tubes (DLTs) are commonly used for one-lung ventilation (OLV) in thoracic surgery and the selection of an optimal size of DLTs is still a humongous task. The purpose of this study was to assess the feasibility and accuracy of the method for selecting an optimal size of DLTs in thoracic surgery. Sixty adult patients requiring a left side double-lumen tube (LDLT) for elective thoracoscopic surgery were included in this study. All patients were randomly allocated to the following two groups: Cuffs Collapsed group (CC group, n = 30) and Cuffs Inflated group (CI group, n = 30). In the Cuffs Collapsed group, the outer diameter of LDLT (the outer diameter of the tracheal and bronchial cuffs when they were collapsed as the outer diameter of the LDLT) matched with the inner diameter of the trachea and bronchus measured by the anesthesiologist on the chest CT slice; In the Cuffs Inflated group, the outer diameter of LDLT (the outer diameter of the tracheal and bronchial cuffs when they were inflated as the outer diameter of the LDLT) matched with the inner diameter of the trachea and bronchus measured by the anesthesiologist on the chest CT slice. The primary outcomes were the incidences of airway complications postoperative such as hoarseness and sore throat. The time of intubation and alignment, the incidences of LDLT displacement and adjustment, the peak airway pressure, the plateau airway pressure and the end-tidal carbon dioxide were also recorded. The incidences of airway complications postoperative such as sore throat and hoarseness were lower in the CI group than the CC group (P < 0.05), the intubation times was shorter in the CI group than the CC group (P < 0.05), while the peak airway pressure, the plateau airway pressure and the end-tidal carbon dioxide during two-lung ventilation and one-lung ventilation were no significant difference between two groups (P > 0.05). The method which matched the inner diameter of the trachea and bronchus measured on chest CT slice with the outer diameter of the tracheal and bronchial cuffs when they were inflated to select an appropriate size of LDLT can reduce the incidence of airway complications.Trials registration: Clinical Trials: gov. no. NCT05739318. Registered at https://classic.clinicaltrials.gov 22/02/2023.

Effect of patient position on the success rate of placing triple-cuffed double lumen endotracheal tubes: a two-center interventional observational study.

Double-lumen endotracheal tubes (DLT) are essential for one-lung ventilation during thoracic surgery. Bronchoscopy is crucial for correct placement of a DLT to avoid complications such as hypoxemia. This study evaluated the effectiveness of the triple-cuffed DLT (tcDLT) in the supine and lateral positions for correct placement without bronchoscopic guidance. This prospective observational study included 167 patients scheduled for elective thoracic surgery requiring one-lung ventilation. The incidence of successful placement of left-sided tcDLTs was compared between the supine and lateral decubitus positions under bronchoscopic surveillance. Successful tcDLT placement was defined as the placement of the proximal end of the bronchial cuff within 5 mm of the carina. Among 153 patients who completed the study, the successful tcDLT placement rate in the lateral position (70.6%) was significantly higher than that in the supine position (50.3%). The rate of difference was 20.3% (95% confidence interval [CI], 10.6-29.9%). The extended successful placement rate, including slightly deeper placements, showed no significant differences between the positions (88.9%; 95% CI, 83.9‒93.9% in supine, 86.3%; 95% CI, 80.8‒91.7% in lateral). tcDLT facilitates correct tube placement in both the supine and lateral positions, with a higher lateral success rate. This finding supports the idea that tcDLTs offer a reliable alternative for lung separation when bronchoscopy is not feasible.

Effect of flow-optimized pressure control ventilation-volume guaranteed (PCV-VG) on postoperative pulmonary complications: a consort study

BackgroundPostoperative pulmonary complications (PPCs) after one-lung ventilation (OLV) significantly impact patient prognosis and quality of life.ObjectiveTo study the impact of an optimal inspiratory flow rate on PPCs in thoracic surgery patients.MethodsOne hundred eight elective thoracic surgery patients were randomly assigned to 2 groups in this consort study (control group: n = 53 with a fixed inspiratory expiratory ratio of 1:2; and experimental group [flow rate optimization group]: n = 55). Measurements of Ppeak, Pplat, PETCO2, lung dynamic compliance (Cdyn), respiratory rate, and oxygen concentration were obtained at the following specific time points: immediately after intubation (T0); immediately after starting OLV (T1); 30 min after OLV (T2); and 10 min after 2-lung ventilation (T4). The PaO2:FiO2 ratio was measured using blood gas analysis 30 min after initiating one-lung breathing (T2) and immediately when OLV ended (T3). The lung ultrasound score (LUS) was assessed following anesthesia and resuscitation (T5). The occurrence of atelectasis was documented immediately after the surgery. PPCs occurrences were noted 3 days after surgery.ResultsThe treatment group had a significantly lower total prevalence of PPCs compared to the control group (3.64% vs. 16.98%; P = 0.022). There were no notable variations in peak airway pressure, airway plateau pressure, dynamic lung compliance, PETCO2, respiratory rate, and oxygen concentration between the two groups during intubation (T0). Dynamic lung compliance and the oxygenation index were significantly increased at T1, T2, and T4 (P < 0.05), whereas the CRP level and number of inflammatory cells decreased dramatically (P < 0.05).ConclusionOptimizing inspiratory flow rate and utilizing pressure control ventilation -volume guaranteed (PCV-VG) mode can decrease PPCs and enhance lung dynamic compliance in OLV patients.

Effects of individualised lung-protective ventilation with lung dynamic compliance-guided positive end-expiratory pressure titration on postoperative pulmonary complications of paediatric video-assisted thoracoscopic surgery: protocol for a randomised controlled trial

IntroductionLung-protective ventilation strategies (LPVS) for one-lung ventilation (OLV) in paediatric patients pose greater challenges than in adults. Optimising LPVS for paediatric OLV to mitigate postoperative pulmonary complications (PPCs) has emerged...

Continuous Positive Airway Pressure versus Differential Lung Ventilation during One Lung Ventilation for Thoracic Surgery.

One lung ventilation (OLV) is a technique used during lung resection surgery to facilitate optimal surgical conditions. However, this may result in severe hypoxemia due to the right-to-left shunt created in the collapsed lung. Several techniques are used to overcome hypoxemia, one of which is continuous positive airway pressure (CPAP) to the non-dependent lung. Another technique is ventilating the non-dependent lung with a minimal volume, thus creating differential lung ventilation (DLV) or split lung ventilation (SLV). In this study, we compared the efficacy of CPAP to DLV during video-assisted thoracoscopic (VATS) lung resection. In this single-center randomized controlled, cross-over study, each patient acted as his control as well as the study. Patients crossed over from SLV to CPAP (or vice versa) with an interval period during which only OLV was used (control period). The primary objective of the study was to observe the changes in oxygenation, ventilation, and the surgeons' perception of the surgical field using CPAP or SLV to the non-ventilated lung during the period of OLV in patients undergoing thoracic surgery. The study revealed that oxygenation was significantly better when using SLV to the non-ventilated lung during the period of OLV (P = 0.03). However, the surgeon found a significantly better surgical field when applying CPAP to the surgical field. The study showed that using SLV to the non-ventilated lung during the period of OLV was superior in terms of oxygenation, although it interfered more with the surgical field.

Common double-lumen tube selection methods overestimate adequate tube sizes in individual patients – a 3D reconstruction study

BackgroundAppropriate selection of double-lumen tube sizes for one-lung ventilation is crucial to prevent airway damage. Current selection methods rely on demographic factors or 2D radiography. Prediction of left bronchial diameter is indispensable for choosing the adequate tube size. This prospective observational study investigates if current selection methods sufficiently predict individuals’ left bronchial diameters for DLT selection compared to the 3D reconstruction.Methods100 patients necessitating thoracic surgery with one-lung ventilation and left-sided double-lumen tubes, ≥ 18 years of age, and a set of chest X-rays and 2D thorax CT scans for 3D reconstruction of the left main bronchus were included between 07/2021 and 06/2023. The cross-validated prediction error and the width of the 95%-prediction intervals of the 3D left main bronchial diameter utilizing linear prediction models were based on current selection methods.ResultsThe mean bronchial diameter in 3D reconstruction was 13.6 ± 2.1 mm. The ranges of the 95%-prediction intervals for the bronchial diameter were 6.4 mm for demographic variables, 8.3 mm for the tracheal diameter from the X-ray, and 5.9 mm for bronchial diameter from the 2D-CT scans. Current methods violated the suggested ‘≥1 mm’ safety criterion in up to 7% (men) and 42% (women). Particularly, 2D radiography overestimated women’s left bronchial diameter. Current methods even allowed the selection of double-lumen tubes with bronchial tube sections greater than the bronchial diameter in women.ConclusionsNeither demographic nor 2D-radiographic methods sufficiently account for the variability of the bronchial diameter. Wide 95%-prediction intervals for the bronchial diameter hamper accurate individual double-lumen tube selection. This increases women’s risk of bronchial damage, particularly if they have other predisposing factors. These patients may benefit from 3D reconstruction of the left main bronchus.Trial registrationNot applicable.

Case Report on a 3-year-old Child Who Underwent Video Assisted Thoracoscopy Surgery (VATS) Bullectomy with One Lung Ventilation (OLV) technique

Case Report on a 3-year-old Child Who Underwent Video Assisted Thoracoscopy Surgery (VATS) Bullectomy with One Lung Ventilation (OLV) technique

Thoracotomy: An Overview of Perioperative Anaesthetic Management

Background: The anesthesiologist's role during open thoracotomy includes using a double lumen tube (DLT) for lung isolation, maintaining oxygenation with one-lung ventilation (OLV), and providing postoperative analgesia. This study aims to describe patient demographics, comorbidities, perioperative anesthetic management, complications, and the effectiveness of epidural catheter analgesia. Methods: In this prospective, observational study, patients who underwent open thoracotomy for decortications were evaluated. Thoracotomy was done under general anaesthesia, OLV with DLT, and epidural analgesia. Postoperatively, all the patients were shifted to the intensive care unit. Collected data included patient demographics, associated co-morbidities, severity of lung diseases, complications, and postoperative recovery. Postoperative analgesia was assessed by the visual analogue scale (0-10). Result: Of 20 patients, 16 were male, and 4 were female, with a mean age of 35 years (range 15-60) and a mean weight of 52 kg (range 36-66). History of hypertension (N=5), hypertension with diabetes (N=3), obstructive lung disease (N=6), restrictive lung disease (N=11), and both combined (N=3) were noted on pre-anesthetic check-ups. Intraoperative complications were hypotension (N=3), desaturation (N=3), respiratory acidosis (N =7), and metabolic acidosis (N=3). Postoperative analgesia was managed with an epidural catheter (N=18) &amp; systemic analgesia (N=2). All patients had uneventful postoperative courses except one patient who had pulmonary edema and did not survive. Conclusion: Patients undergoing open thoracotomy had an increased risk for adverse perioperative outcomes. The incidences of perioperative morbidity are high in patients with associated comorbidities. Proper OLV strategy helps to correct intraoperative desaturation. Epidural analgesia plays a key role in postoperative recovery.

Epinephrine Alleviates Intraoperative Hypoxemia in an Infant with Bronchogenic Cyst: A Case Report

An 11-month-old male infant was diagnosed with bronchogenic cysts and required a right lung cystectomy. The surgical approach involved one-lung ventilation (OLV) using lung isolation techniques. During the procedure, oxygenation could not be adequately maintained using conventional methods. Ultimately, a successful outcome was achieved by administering low-dose epinephrine via a microinjection pump. This case report discusses the methods for achieving OLV during thoracic surgery in infants and the feasibility of using small doses of epinephrine during OLV in pediatric thoracic surgery when encountering intraoperative hypoxia.

The Hemodynamic Changes Induced by Lung Recruitment Maneuver to Predict Fluid Responsiveness in Children during One Lung Ventilation-A Prospective Observational Study.

The prediction of fluid responsiveness in critical patients helps clinicians in decision making to avoid either under- or overloading of fluid. This study was designed to determine whether lung recruitment maneuver (LRM) would have an effect on the predictability of fluid responsiveness by the changes of hemodynamic parameters in pediatric patients who were receiving lung-protective ventilation and one-lung ventilation (OLV). A total of 34 children, aged 1-6 years old, scheduled for heart surgeries via right thoracotomy were enrolled. Patients were anesthetized and OLV with lung-protection ventilation settings was established, and then, positioned on left lateral decubitus. LRM and volume expansion (VE) were performed in sequence. Heart rate (HR), systolic arterial pressure (SAP), mean arterial pressure (MAP) diastolic arterial pressure (DAP), stroke volume (SV), stroke volume variation (SVV), and pulse pressure variation (PPV) were recorded via an A-line based monitor system at the following time points: before and after LRM (T1 and T2) and before and after VE (T3 and T4). An increase in stroke volume (SV) or mean arterial pressure (MAP) of ≥10% following fluid loading identified fluid responders. The predictability of fluid responsiveness by the changes of SV (ΔSVLRM) and MAP (ΔMAPLRM) after LRM and VE were statistically evaluated by receiver operating characteristic curves [area under the curves (AUC)]. SVs in all patients were significantly decreased after LRM (p < 0.01) and then, increased and returned to baseline after VE (p < 0.01). In total, 16 out of 34 patients who were fluid responders had significantly lower SV after LRM compared to that in fluid non-responders. The area under the receiver operating characteristic curves for ΔSVLRM was 0.828 (95% confidence interval [CI], 0.660 to 0.935; p < 0.001) and it indicated that ΔSVLRM was able to predict the fluid responsiveness of pediatric patients. MAPs in all patients were also decreased significantly after LRM, and 12 of them fell into the category of fluid responders after VE. Statistically, ΔMAPLRM did not predict fluid responsiveness when LRM was considered as an influential factor (p = 0.07). ΔSVLRM, but not ΔMAPLRM, showed great reliability in the prediction of the fluid responsiveness following VE in children during one-lung ventilation with lung-protective settings. ChiCTR2300070690.

Association between mechanical power during one-lung ventilation and pulmonary complications after thoracoscopic lung resection surgery: a prospective observational study

BackgroundThe role of mechanical power on pulmonary outcomes after thoracic surgery with one-lung ventilation was unclear. We investigated the association between mechanical power and postoperative pulmonary complications in patients undergoing thoracoscopic lung resection surgery.MethodsIn this single-center, prospective observational study, 622 patients scheduled for thoracoscopic lung resection surgery were included. Volume control mode with lung protective ventilation strategies were implemented in all participants. The primary endpoint was a composite of postoperative pulmonary complications during hospital stay. Multivariable logistic regression models were used to evaluate the association between mechanical power and outcomes.ResultsThe incidence of pulmonary complications after surgery during hospital stay was 24.6% (150 of 609 patients). The multivariable analysis showed that there was no link between mechanical power and postoperative pulmonary complications.ConclusionsIn patients undergoing thoracoscopic lung resection with standardized lung-protective ventilation, no association was found between mechanical power and postoperative pulmonary complications.Trial registrationTrial registration number: ChiCTR2200058528, date of registration: April 10, 2022.

Risk factors for postoperative pulmonary complications in elderly patients undergoing video-assisted thoracoscopic surgery lobectomy under general anesthesia: a retrospective study

BackgroundThe objective of this study is to identify and evaluate the risk factors associated with the development of postoperative pulmonary complications (PPCs) in elderly patients undergoing video-assisted thoracoscopic surgery lobectomy under general anesthesia.MethodsThe retrospective study consecutively included elderly patients (≥ 70 years old) who underwent thoracoscopic lobectomy at Xuanwu Hospital of Capital Medical University from January 1, 2018 to August 31, 2023. The demographic characteristics, the preoperative, intraoperative and postoperative parameters were collected and analyzed using multivariate logistic regression to identify the prediction of risk factors for PPCs.Results322 patients were included for analysis, and 115 patients (35.7%) developed PPCs. Multifactorial regression analysis showed that ASA ≥ III (P = 0.006, 95% CI: 1.230 ∼ 3.532), duration of one-lung ventilation (P = 0.033, 95% CI: 1.069 ∼ 4.867), smoking (P = 0.027, 95% CI: 1.072 ∼ 3.194) and COPD (P = 0.015, 95% CI: 1.332 ∼ 13.716) are independent risk factors for PPCs after thoracoscopic lobectomy in elderly patients.ConclusionRisk factors for PPCs are ASA ≥ III, duration of one-lung ventilation, smoking and COPD in elderly patients over 70 years old undergoing thoracoscopic lobectomy. It is necessary to pay special attention to these patients to help optimize the allocation of resources and enhance preventive efforts.

Effect of a 3D-printed reconstruction automated matching system for selecting the size of a left double-lumen tube: a study protocol for a prospective randomised controlled trial

IntroductionLung isolation is primarily accomplished using a double-lumen tube (DLT) or bronchial blocker. A precise and accurate size of the DLT is a prerequisite for ensuring its accurate placement. Three-dimensional...

Managing One-Lung Ventilation in Tracheostomized Patients: A 6-Year Retrospective Analysis

Abstract Background To ensure safe and optimal surgical conditions in thoracic surgery, one-lung ventilation is crucial. Various techniques exist to achieve one-lung ventilation. Tracheotomized patients who require one-lung ventilation represent a unique and rare subgroup that demands specialized knowledge and skills. The very limited literature has discussed alternative methods, no randomized controlled trials have addressed this issue yet. Methods We performed a retrospective analysis of patients who underwent one-lung ventilation in the Department of Thoracic Surgery of a German University Hospital between 2016 and 2021. The study assessed patient demographics, airway management techniques, ventilation parameters, and adverse events. Results In 3,197 anesthesia procedures during the observation period, 152 patients had an existing tracheostomy, of which 56 required one-lung ventilation. Among others in 42 cases, a tracheostomy tube was combined with a bronchial blocker, and in 10 cases, a double-lumen tracheostomy tube was used. There were no severe complications. Intraoperative dislocations that required repositioning of the device occurred in six patients (13.3%) with bronchial blockers and one patient with double-lumen tracheostomy tube (10%). Conclusion The management of one-lung ventilation in tracheotomized patients presents unique challenges. While double-lumen tracheostomy tubes have specific advantages, we recommend considering their use carefully. For most tracheotomized patients, bronchial blockers in conjunction with a tracheostomy tube are used, which offers safety and practicality, irrespective of the tracheostomy's age or type. Further research and randomized controlled trials are warranted to establish best practices for one-lung ventilation in this unique patient population.

Effects of positive end-expiratory pressure on pulmonary perfusion distribution and intrapulmonary shunt during one-lung ventilation in pigs A randomized crossover study.

During one-lung ventilation (OLV), positive end-expiratory pressure (PEEP) can improve lung aeration, but might over-distend lung units and increase intrapulmonary shunt. We hypothesized that higher PEEP shifts pulmonary perfusion from the ventilated to the non-ventilated lung, resulting in a U-shaped relationship with intrapulmonary shunt during OLV. In nine anesthetized female pigs, a thoracotomy was performed and intravenous lipopolysaccharide infused to mimic the inflammatory response of thoracic surgery. Animals underwent OLV in supine position with PEEP of 0 cmH2O, 5 cmH2O, titrated to best respiratory system compliance, and 15 cmH2O (PEEP0, PEEP5, PEEPtitr, and PEEP15, respectively, 45 min each, Latin square sequence). Respiratory, hemodynamic, and gas exchange variables were measured. The distributions of perfusion and ventilation were determined by i.v. fluorescent microspheres and computed tomography, respectively. Compared to two lung ventilation, the driving pressure increased with OLV, irrespective of the PEEP level. During OLV, cardiac output was lower at PEEP15 (5.5 ± 1.5 l/min) than PEEP0 (7.6 ± 3 l/min) and PEEP5 (7.4 ± 2.9 l/min; P=0.004), while the intrapulmonary shunt was highest at PEEP0 (PEEP0: 48.1 ± 14.4 %; PEEP5: 42.4 ± 14.8 %; PEEPtitr: 37.8 ± 11.0 %; PEEP15: 39.0 ± 10.7 %; P=0.027). The relative perfusion of the ventilated lung did not differ among PEEP levels (PEEP0: 65.0 ± 10.6 %; PEEP5:68.7 ± 8.7 %; PEEPtitr: 68.2 ± 10.5 %; PEEP15: 58.4 ± 12.8%; P=0.096), but the centers of relative perfusion and ventilation in the ventilated lung shifted from ventral to dorsal, and from cranial to caudal zones with increasing PEEP. In this experimental model of thoracic surgery, higher PEEP during OLV did not shift the perfusion from the ventilated to the non-ventilated lung, thus not increasing intrapulmonary shunt. This study was registered and approved by the Landesdirektion Dresden, Germany (25-5131/496/33).

A novel combined approach to placement of a double lumen endobronchial tube using a video laryngoscope and fiberoptic bronchoscope: a retrospective chart review

BackgroundThe objective of this study was to evaluate a modern combined video laryngoscopy and flexible fiberoptic bronchoscope approach to placement of a double lumen endobronchial tube and further characterize potential strengths and weaknesses of this approach.MethodsRetrospective chart review was conducted at our single institution, academic medical center, tertiary-care hospital. Patients aged 18 years of age or older were evaluated who underwent thoracic surgery and one-lung ventilation with placement of a double lumen endobronchial tube using a novel combined video laryngoscopy and flexible fiberoptic bronchoscope approach. No interventions were performed.ResultsDemographics and induction and intubation documentation were reviewed for 21 patients who underwent thoracic surgery and one-lung ventilation with placement of a double lumen endobronchial tube using a novel combined video laryngoscopy and flexible fiberoptic bronchoscope approach. First pass success using the combined approach was 86% (18/21). The five patients with an anticipated difficult airway had successful double lumen endobronchial tube placement on the first attempt. There were no instances of desaturation during double lumen endobronchial tube placement. No airway complications related to double lumen endobronchial tube placement were recorded.ConclusionUse of a combined approach employing video laryngoscopy and a flexible fiberoptic bronchoscope may represent a reliable alternative approach to placement of double lumen endobronchial tubes.

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.

Comparative effects of variable versus conventional volume-controlled one-lung ventilation on gas exchange and respiratory system mechanics in thoracic surgery patients: A randomized controlled clinical trial

BackgroundMechanical ventilation with variable tidal volumes (V-VCV) has the potential to improve lung function during general anesthesia. We tested the hypothesis that V-VCV compared to conventional volume-controlled ventilation (C-VCV) would improve intraoperative arterial oxygenation and respiratory system mechanics in patients undergoing thoracic surgery under one-lung ventilation (OLV). MethodsPatients were randomized to V-VCV (n = 39) or C-VCV (n = 39). During OLV tidal volume of 5 mL/kg predicted body weight (PBW) was used. Both groups were ventilated with a positive end-expiratory pressure (PEEP) of 5 cm H2O, inspiration to expiration ratio (I:E) of 1:1 (during OLV) and 1:2 during two-lung ventilation, the respiratory rate (RR) titrated to arterial pH, inspiratory peak-pressure ≤ 40 cm H2O and an inspiratory oxygen fraction of 1.0. ResultsSeventy-five out of 78 Patients completed the trial and were analyzed (dropouts were excluded). The partial pressure of arterial oxygen (PaO2) 20 min after the start of OLV did not differ among groups (V-VCV: 25.8 ± 14.6 kPa vs C-VCV: 27.2 ± 15.3 kPa; mean difference [95% CI]: 1.3 [−8.2, 5.5], P = 0.700). Furthermore, intraoperative gas exchange, intraoperative adverse events, need for rescue maneuvers due to desaturation and hypercapnia, incidence of postoperative pulmonary and extra-pulmonary complications, and hospital free days at day 30 after surgery did not differ between groups. ConclusionsIn thoracic surgery patients under OLV, V-VCV did not improve oxygenation or respiratory system mechanics compared to C-VCV.Ethical Committee: EK 420092019.Trial registration: at the German Clinical Trials Register: DRKS00022202 (16.06.2020).

Continuous positive airway pressure combined with small-tidal-volume ventilation on arterial oxygenation and pulmonary shunt during one-lung ventilation in patients undergoing video-assisted thoracoscopic lobectomy: A randomized, controlled study.

One-lung ventilation (OLV) is frequently applied during video-assisted thoracoscopic surgery (VATS) airway management to collapse and isolate the nondependent lung (NL). OLV can give rise to hypoxemia as a result of the pulmonary shunting produced. Our study aimed to assess the influence of continuous positive airway pressure (CPAP) combined with small-tidal-volume ventilation on improving arterial oxygenation and decreasing pulmonary shunt rate (QS/QT) without compromising surgical field exposure during OLV. Forty-eight patients undergoing scheduled VATS lobectomy were enrolled in this research and allocated into three groups at random: C group (conventional ventilation, no NL ventilation intervention was performed), LP group (NL was ventilated with lower CPAP [2 cmH2O] and a 40-60 mL tidal volume [TV]), and HP group (NL was ventilated with higher CPAP [5 cmH2O] and a 60-80 mL TV). Record the blood gas analysis data and calculate the QS/QT at the following time: at the beginning of the OLV (T0), 30 min after OLV (T1), and 60 min after OLV (T2). Surgeons blinded to ventilation techniques were invited to evaluate the surgical fields. The demography data of the three groups were consistent with the surgical data. At T1, PaO2 in the HP group was substantially higher compared to the C group (P < 0.05), while there was no significant difference in the LP group (P > 0.05). At T1-T2, PaCO2 in the LP and HP groups was significantly less than that in the C group (P < 0.05). At T1, the QS/QT values of groups C, LP, and HP were 29.54 ± 6.89%, 22.66 ± 2.08%, and 19.64 ± 5.76%, respectively, and the QS/QT values in the LP and HP groups markedly reduced (P < 0.01). The surgical field's evaluation by the surgeon among the three groups was not notable (P > 0.05). CPAP combined with small-tidal-volume ventilation effectively improved arterial oxygenation and reduced QS/QT and PaCO2 without compromising surgical field exposure during OLV. Among them, 5 cmH2O CPAP + 60-80 ml TV ventilation had a better effect on improving oxygenation.