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

BACKGROUND: Postoperative pulmonary complications (PPCs) after one-lung ventilation (OLV) significantly impact patient prognosis and quality of life. OBJECTIVE: To study the impact of an optimal inspiratory flow rate on PPCs in thoracic surgery patients. METHODS: One 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. RESULTS: The 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). CONCLUSION: Optimizing inspiratory flow rate and utilizing pressure control ventilation -volume guaranteed (PCV-VG) mode can decrease PPCs and enhance lung dynamic compliance in OLV patients.

Unveiling the protective role of sevoflurane in video-assisted thoracoscopic surgery associated-acute lung injury: Inhibition of ferroptosis.

Acute lung injury (ALI) frequently occurs after video-assisted thoracoscopic surgery (VATS). Ferroptosis is implicated in several lung diseases. Therefore, the disparate effects and underlying mechanisms of the two commonly used anesthetics (sevoflurane (Sev) and propofol) on VATS-induced ALI need to be clarified. In the present study, enrolled patients were randomly allocated to receive Sev (group S) or propofol anesthesia (group P). Intraoperative oxygenation, morphology of the lung tissue, expression of ZO-1, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), superoxide dismutase (SOD), glutathione (GSH), Fe2+, glutathione peroxidase 4 (GPX4), and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/nuclear factor erythroid-2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway in the lung tissue as well as the expression of TNF-α and IL-6 in plasma were measured. Postoperative complications were recorded. Of the 85 initially screened patients scheduled for VATS, 62 were enrolled in either group S (n = 32) or P (n = 30). Compared with propofol, Sev substantially (1) improved intraoperative oxygenation; (2) relieved histopathological lung injury; (3) increased ZO-1 protein expression; (4) decreased the levels of TNF-α and IL-6 in both the lung tissue and plasma; (5) increased the contents of GSH and SOD but decreased Fe2+ concentration; (6) upregulated the protein expression of p-AKT, Nrf2, HO-1, and GPX4. No significant differences in the occurrence of postoperative outcomes were observed between both groups. In summary, Sev treatment, in comparison to propofol anesthesia, may suppress local lung and systemic inflammatory responses by activating the PI3K/Akt/Nrf2/HO-1 pathway and inhibiting ferroptosis. This cascade of effects contributes to the maintenance of pulmonary epithelial barrier permeability, alleviation of pulmonary injury, and enhancement of intraoperative oxygenation in patients undergoing VATS.

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

BACKGROUND: 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). METHODS: 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)]. RESULTS: 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). CONCLUSIONS: 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. TRIAL REGISTRATION: ChiCTR2300070690.

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

BACKGROUND: The 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. METHODS: In 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. RESULTS: The 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. CONCLUSIONS: In patients undergoing thoracoscopic lung resection with standardized lung-protective ventilation, no association was found between mechanical power and postoperative pulmonary complications. TRIAL REGISTRATION: Trial 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.

BACKGROUND: The 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. METHODS: The 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. RESULTS: 322 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. CONCLUSION: Risk 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.

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.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Contralateral Tension Pneumothorax in One-Lung Ventilation: A Case Report and Systematic Review.

Contralateral tension pneumothorax is a rare but fatal complication of one-lung ventilation. The life-saving decompression of pleural space was frequently delayed by the difficult confirmation of diagnosis because of general anesthesia that masks specific clinical presentations when the patient is alert. We reported a case of tension pneumothorax in a patient who underwent thoracic spine instrumentation. There were no contralateral tension pneumothorax cases on file from the search of the Anesthesia Quality Institute Closed Claims Database from 2001 to 2017. We systematically searched PubMed, Ovid MEDLINE, Embase, and Google Scholar. Over the past 30 years, there were 21 single case reports and two case series were retrieved. It was a consensus that difficult confirmation of the diagnosis of contralateral tension pneumothorax is the culprit of delayed life-saving intervention. Difficulty of oxygenation with increasing inspiratory pressure was usually the first sign suggesting contralateral pneumothorax; however, earlier presentations of cardiovascular system failure than respiratory failure have significantly increased the incidence of cardiac arrest and death. It is paramount to maintain a high suspicion of tension pneumothorax. The application of esophageal stethoscope, lung ultrasound, and simulator training may improve the chance of early diagnosis and patient outcome.

Efficacy and safety of video double-lumen tube intubation in lateral position in patients undergoing thoracic surgery: a randomized controlled trial.

BACKGROUND: Video double-lumen tube (VDLT) intubation in lateral position is a potential alternative to intubation in supine position in patients undergoing thoracic surgery. This non-inferiority trial assessed the efficacy and safety of VDLT intubation in lateral position. METHODS: Patients (18-70 yr) undergoing right thoracoscopic lung surgery were randomized to either the left lateral position group (group L) or the supine position group (group S). The VDLT was placed under video larygoscopy. The primary endpoint was the intubation time. Secondary endpoints included VDLT displacement rate, intubation failure rate, the satisfaction of surgeon and nurse, and intubation-related adverse events. RESULTS: The analysis covered 80 patients. The total intubation time was 52.0 [20.4]s in group L and 34.3 [13.2]s in group S, with a mean difference of 17.6 s [95% confidence interval (CI): 9.9 s to 25.3 s; P = 0.050], failing to demonstrate non-inferiority with a non-inferiority margin of 10 s. Group L, compared with group S, had significantly lower VDLT displacement rate (P = 0.017) and higher nurse satisfaction (P = 0.026). No intubation failure occurred in any group. Intubation complications (P = 0.802) and surgeon satisfaction (P = 0.415) were comparable between two groups. CONCLUSIONS: The lateral VDLT intubation took longer time than in the supine position, and non-inferiority was not achieved. The incidence of displacement as the secondary endpoint was lower in the L group, possibly due to changing body positions beforehand. The indication of lateral VDLT intubation should be based on a balance between the safety of airway management and the lower incidence of displacement. TRIAL REGISTRATION: The study was registered at Chictr.org.cn with the number ChiCTR2200064831 on 19/10/2022.

Effect of ultrasound-guided stellate ganglion block on lung protection for patients undergoing one-lung ventilation.

OBJECTIVE: To explore the potential effect of ultrasound-guided stellate ganglion block (SGB) on lung protection for patients undergoing one-lung ventilation (OLV). METHODS: A total of 123 patients undergoing elective one-lung ventilation surgery were selected as research subjects in this prospective study. These patients were randomly divided into the SGB group, control group and blank group on average. Stellate ganglion block was carried out in the SGB and control groups. Patients in the SGB group were injected with 6 ml mixture of 0.25% ropivacaine hydrochloride and 1% lidocaine hydrochloride, while those in the control group were injected with 6 mL of 0.9% saline. Punctures weren't performed for patients in the blank group. The same induction and maintenance of general anesthesia was adopted for all three groups. Hemodynamics, respiratory parameters and arterial blood gas analysis were recorded after entering the operation room (T0), pre-OLV (T1), 30 min after OLV (T2), 60 min after OLV (T3), at the end of surgery (T4), and 30 min after extubation (T5). Oxygenation index (OI), pulmonary shunt fraction (Qs/Qt) and pH value were compared at different time points. Intravenous serum was collected at T0, T3 and T5 for the detection of surfactant proteins A (SP-A), superoxide dismutase (SOD), malondialdehyde (MDA), interleukin-6 (IL-6) and interleukin-10 (IL-10) levels, respectively. The complications related to SGB after surgery and the postoperative pulmonary complications within 72 h were recorded. RESULTS: At T1, T2, and T3, MAP level in SGB group was lower than that in blank and control groups (P<0.05). At T2, and T3, SGB group had lower hear rate (HR), peak airway pressure (Ppeak) and tidal volume (TV) than blank and control groups (all P<0.05). From T2 to T5, SGB group had higher OI but lower Qs/Qt than blank and control groups (both P<0.05). At T3 and T5, SGB group had lower SP-A, IL-6, and MDA levels but higher IL-10 and SOD levels than blank and control groups (all P<0.05). There was one case of hypoxemia in the blank group within 72 h after surgery. CONCLUSION: Ultrasound-guided SGB has lung-protective effects on patients undergoing OLV, which significantly improves patients' OI, reduces intrapulmonary shunts, declines ventilator-induced lung damage, and inhibits inflammatory response as well as oxidative stress (China Clinical Trial Registry, registration number ChiCTR2000033385, https://www.chictr.org.cn).

Comparison of early postoperative pulmonary complications between two-lung ventilation with artificial pneumothorax and one-lung ventilation with bronchial blockade in patients undergoing minimally invasive esophagectomy: a retrospective propensity score-matched cohort study.

Background: Two-lung ventilation (TLV) with artificial carbon dioxide (CO2) pneumothorax is used during the thoracoscopic phase of minimally invasive esophagectomy (MIE). However, the impact of TLV with artificial pneumothorax on postoperative pulmonary complications (PPCs) after MIE is unclear. This study aimed to compare the incidence of early PPCs between TLV with CO2 pneumothorax and one-lung ventilation (OLV) with bronchial blockade in patients undergoing MIE. Methods: Five hundred ninety-three patients with esophageal cancer who underwent elective MIE with two-field lymph node dissection were analyzed. Patients in the TLV group were intubated using a single-lumen endotracheal tube and underwent surgery using TLV with artificial CO2 pneumothorax. Patients in the OLV group underwent surgery using OLV with a bronchial blocker. Patient characteristics and intraoperative and PPC data were collected and analyzed. Propensity score matching (PSM) was performed to reduce confounding bias. Results: The TLV and OLV group comprised 513 and 80 patients, respectively. PSM matched 197 TLV group and 73 OLV group patients. Incidence of pneumonia within the first 3 days of surgery was higher in the TLV group (11.7% vs. 4.1%) but the difference was not significant (P=0.06). The incidence of infiltrates on chest radiography was 36.0% in the TLV group and 28.8% in the OLV group (P=0.26). Incidence of other major PPCs requiring treatment and major non-pulmonary postoperative complications did not significantly differ between the groups. Length of hospital stay was significantly longer in the TLV group (13.0 vs. 11.0 days; P=0.03). Conclusions: Compared with OLV with bronchial blockade, TLV with CO2 pneumothorax did not reduce the incidence of early PPCs after MIE.

Single-Lung Ventilation in Infants for Surgical Repair of Coarctation of The Aorta Without Cardiopulmonary Bypass.

OBJECTIVE: To investigate the effect of improving the operative field and postoperative atelectasis of single-lung ventilation (SLV) in the surgical repair of coarctation of the aorta (CoA) in infants without the use of cardiopulmonary bypass (CPB). METHODS: This was a retrospective cohort study. The clinical data of 28 infants (aged 1 to 4 months, weighing between 4.2 and 6 kg) who underwent surgical repair of CoA without CPB from January 2019 to May 2022 were analyzed. Fourteen infants received SLV with a bronchial blocker (Group S), and the other 14 infants received routine endotracheal intubation and bilateral lung ventilation (Group R). RESULTS: In comparison to Group R, Group S exhibited improved exposure of the operative field, a lower postoperative atelectasis score (P<0.001), reduced prevalence of hypoxemia (P=0.01), and shorter durations of operation, mechanical ventilation, and ICU stay (P=0.01, P<0.001, P=0.03). There was no difference in preoperative information or perioperative respiratory and circulatory indicators before SLV, 10 minutes after SLV, and 10 minutes after the end of SLV between the two groups (P>0.05). Intraoperative bleeding, intraoperative positive end-expiratory pressure (PEEP), and systolic pressure gradient across the coarctation after operation were also not different between the two groups (P>0.05). CONCLUSION: This study demonstrates that employing SLV with a bronchial blocker is consistent with enhanced operative field, reduced operation duration, lower prevalence of intraoperative hypoxemia, and fewer postoperative complications during the surgical repair of CoA in infants without the use of CPB.

Video double-lumen tube for one lung ventilation: implementation and experience in 343 cases of routine clinical use during the first 20 months of the SARS-CoV-2 pandemic.

BACKGROUND: Double-lumen tubes (DLTs) are the preferred device for lung isolation. Conventional DLTs (cDLT) need a bronchoscopic position control. Visualisation of correct DLT positioning could be facilitated by the use of a video double-lumen tube (vDLT). During the SARS-CoV-2-pandemic, avoiding aerosol-generation was suggesting using this device. In a large retrospective series, we report both general and pandemic related experiences with the device. METHODS: All anesthesia records from patients aged 18 years or older undergoing surgery from April 1st, 2020 to December 31st, 2021 in the department of thoracic surgery requiring intraoperative lung isolation were analyzed retrospectively. RESULTS: During the investigation period 343 left-sided vDLTs (77.4%) and 100 left-sided cDLTs (22.6%) were used for one lung ventilation. In the vDLT group bronchoscopy could be reduced by 85.4% related to the cDLT group. Additional bronchoscopy to reach or maintain correct position was needed in 11% of the cases. Other bronchoscopy indications occured in 3.6% of the cases. With cDLT, in 1% bronchoscopy for other indications than conforming position was observed. CONCLUSIONS: The Ambu® VivaSight™ vDLT is an efficient, easy-to-use and safe airway device for the generation of one lung ventilation in patients undergoing thoracic surgery. The vDLT implementation was achieved easily with full interchangeability to the left-sided cDLT. Using the vDLT can reduce the need for aerosol-generating bronchoscopic interventions by 85.4%. Continuous video view to the carina enabling position monitoring of the DLT without need for bronchoscopy might be beneficial for both employee's and patient's safety.

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

BACKGROUND: The 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. METHODS: Retrospective 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. RESULTS: Demographics 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. CONCLUSION: Use 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.

Preoperative preparation and postoperative care in children in thoracic surgery.

Anesthesia for pediatric patients undergoing thoracic surgery continues to be distinctive due to differing anatomical and physiological characteristics compared to adults. Adequate preoperative preparation, appropriate tool selection for providing one-lung ventilation, perioperative pain management, and a multidisciplinary approach can ensure higher quality postoperative care. In this review, the perioperative anesthesia management for pediatric patients undergoing thoracic surgery will be discussed, starting from the preoperative preparation phase. Additionally, the issues related to the application and management of one-lung ventilation will also be assessed.

Laparoscopic Repair Following a Delayed Presentation of Traumatic Diaphragmatic Hernia: A Case Report.

Traumatic diaphragmatic hernia is a rare condition that occurs after trauma, and some patients have a delayed presentation. A laparoscopic approach is rarely used to repair traumatic diaphragmatic hernias. We encountered a case of asymptomatic diaphragmatic hernia diagnosed after a comprehensive medical examination. A 71-year-old woman was diagnosed with a delayed presentation of traumatic diaphragmatic hernia with prolapse of the greater omentum owing to a traffic injury 20 years ago. Surgery was performed laparoscopically using three ports, and intraoperative respiratory management was performed using a double-lumen tube. The 2.5-cm-diameter hernial orifice was sutured under contralateral one-lung ventilation after the greater omentum was returned to the abdominal cavity. The patient's postoperative course was uneventful, and she was discharged on the third day. Intraoperative strategies such as respiratory management and the laparoscopic approach play a crucial role in ensuring favorable postoperative outcomes. The last follow-up was at six months post-operation, and the patient was doing well.

Effects of unilateral superimposed high-frequency jet ventilation on porcine hemodynamics and gas exchange during one-lung flooding.

BACKGROUND: Superimposed high-frequency jet ventilation (SHFJV) is suitable for respiratory motion reduction and essential for effective lung tumor ablation. Fluid filling of the target lung wing one-lung flooding (OLF) is necessary for therapeutic ultrasound applications. However, whether unilateral SHFJV allows adequate hemodynamics and gas exchange is unclear. AIM: To compared SHFJV with pressure-controlled ventilation (PCV) during OLF by assessing hemodynamics and gas exchange in different animal positions. METHODS: SHFJV or PCV was used alternatingly to ventilate the non-flooded lungs of the 12 anesthetized pigs during OLF. The animal positions were changed from left lateral position to supine position (SP) to right lateral position (RLP) every 30 min. In each position, ventilation was maintained for 15 min in both modalities. Hemodynamic variables and arterial blood gas levels were repeatedly measured. RESULTS: Unilateral SHFJV led to lower carbon dioxide removal than PCV without abnormally elevated carbon dioxide levels. SHFJV slightly decreased oxygenation in SP and RLP compared with PCV; the lowest values of PaO2 and PaO2/FiO2 ratio were found in SP [13.0; interquartile range (IQR): 12.6-5.6 and 32.5 (IQR: 31.5-38.9) kPa]. Conversely, during SHFJV, the shunt fraction was higher in all animal positions (highest in the RLP: 0.30). CONCLUSION: In porcine model, unilateral SHFJV may provide adequate ventilation in different animal positions during OLF. Lower oxygenation and CO2 removal rates compared to PCV did not lead to hypoxia or hypercapnia. SHFJV can be safely used for lung tumor ablation to minimize ventilation-induced lung motion.

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.

BACKGROUND: Mechanical 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). METHODS: Patients 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. RESULTS: Seventy-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. CONCLUSIONS: In 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).

Advances in Minimally Invasive Procedures of the Thoracic Cavity.

Significant advances in veterinary minimally invasive surgeries and procedures have occurred in the past 10 years. These advances have been allowed due to continual research into optimizing working space through one-lung ventilation techniques and carbon dioxide insufflation. Additionally, minimally invasive surgery enthusiasts have joined forces with interventionalists and, in many cases, physicians to push the boundaries, minimize pain, suffering, and time away from owners with advances in a variety of procedures. Several larger multi-institutional retrospective studies on various disease processes allow veterinarians and owners to understand that minimally invasive approaches allow for outcomes comparable to traditional open surgery and, in some cases, may now be considered the standard of care in canine and feline patients.

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

OBJECTIVE: Test the hypothesis that one-lung ventilation with variable tidal volume improves intraoperative oxygenation and reduces postoperative pulmonary complications after lung resection. BACKGROUND: Constant 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. DESIGN: Randomized trial. SETTING: Operating rooms and a post-anesthesia care unit. PATIENTS: Adults 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. INTERVENTIONS: Patients 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. MEASUREMENTS: The primary outcome was intraoperative oxygenation; secondary outcomes were postoperative pulmonary complications, mortality within 90 days of surgery, heart rate, and SpO2/FiO2 ratio. RESULTS: Data 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. CONCLUSION: One-lung ventilation with variable tidal volume does not meaningfully improve intraoperative oxygenation, and does not reduce postoperative pulmonary complications.