Management of mechanical ventilation during laparoscopic surgery

The Impact of Pneumoperitoneum on Mean Expiratory Flow Rate: Observational Insights from Patients with Healthy Lungs

BACKGROUND/OBJECTIVES

Surgical pneumoperitoneum (PP) significantly impacts volume-controlled ventilation, characterized by reduced respiratory compliance, elevated peak inspiratory pressure, and an accelerated expiratory phase due to an earlier onset of the airway pressure gradient. We hypothesized that this would shorten expiratory time, potentially increasing expiratory flow rate compared to pneumoperitoneum conditions. Calculations were performed to establish correlations between respiratory parameters and the mean increase in expiratory flow rate relative to baseline.

METHODS

Mechanical ventilation parameters were recorded for 67 patients both pre- and post-PP. Ventilator settings were standardized with a tidal volume of 6 mL/kg, a respiratory rate of 12 breaths per minute, a PEEP of 3 cmH2O, an inspiratory time of 2 s, and an inspiratory-to-expiratory ratio of 1:1.5 (I:E).

RESULTS

The application of PP increased both peak inspiratory pressure and mean expiratory flow rate by 28% compared to baseline levels. The elevated intra-abdominal pressure of 20 cmH2O resulted in a 34% reduction in dynamic chest compliance, a 50% increase in elastance, and a 20% increase in airway resistance. The mean expiratory flow rate increments relative to baseline showed a significant negative correlation with elastance (p = 0.0119) and a positive correlation with dynamic compliance (p = 0.0028) and resistance (p = 0.0240).

CONCLUSIONS

A PP of 20 cmH2O resulted in an increase in the mean expiratory flow rate in the conventional I:E ratio in the volume-ventilated mode. PP reduces lung and chest wall compliance by elevating the diaphragm, compressing the thoracic cavity, and increasing airway pressures. Consequently, the lungs and chest wall stiffen, requiring greater ventilatory effort and accelerating expiratory flow due to increased airway resistance and altered pulmonary mechanics. Prolonging the inspiratory phase through I:E ratio adjustment helps maintain peak inspiratory pressures closer to baseline levels, and this method enhances the safety and efficacy of mechanical ventilation in maintaining optimal respiratory function during laparoscopic surgery.

Underneath Images and Robots, Looking Deeper into the Pneumoperitoneum: A Narrative Review

Laparoscopy offers numerous advantages over open procedures, minimizing trauma, reducing pain, accelerating recovery, and shortening hospital stays. Despite other technical advancements, pneumoperitoneum insufflation has received little attention, barely evolving since its inception. We explore the impact of pneumoperitoneum on patient outcomes and advocate for a minimally invasive approach that prioritizes peritoneal homeostasis. The nonlinear relationship between intra-abdominal pressure (IAP) and intra-abdominal volume (IAV) is discussed, emphasizing IAP titration to balance physiological effects and surgical workspace. Maintaining IAP below 10 mmHg is generally recommended, but factors such as patient positioning and surgical complexity must be considered. The depth of neuromuscular blockade (NMB) is explored as another variable affecting laparoscopic conditions. While deep NMB appears favorable for surgical stillness, achieving a balance between IAP and NMB depth is crucial. Temperature and humidity management during pneumoperitoneum are crucial for patient safety and optical field quality. Despite the debate over the significance of temperature drop, humidification and the warming of insufflated gas offer benefits in peritoneal homeostasis and visual clarity. In conclusion, there is potential for a paradigm shift in pneumoperitoneum management, with dynamic IAP adjustments and careful control of insufflated gas temperature and humidity to preserve peritoneal homeostasis and improve patient outcomes in minimally invasive surgery.

Comparison of a Valveless Trocar System and Conventional Insufflation in Pediatric Urologic Surgery

Background: Conventional operative insufflation uses a one-way trocar to handle instruments while maintaining pneumoperitoneum. In 2007, the AirSeal® valveless trocar insufflation system was introduced, which maintains stable pneumoperitoneum while continuously evacuating smoke. Although this device has been validated in adult patients, it has not been extensively validated in the pediatric population. Materials and Methods: A retrospective cohort study of pediatric urology patients aged 0 to 21 who underwent laparoscopic pyeloplasty between March 2016 and October 2021 was performed. Intraoperative physiologic parameters, procedure characteristics, postoperative outcomes, and demographics of each patient in whom either AirSeal insufflation system (AIS) or conventional insufflation system (CIS) was utilized were obtained from hospital records. Data were compared across the AIS and CIS cohorts. The primary outcomes were intraoperative anesthetic and physiologic parameters, including end tidal carbon dioxide, oxygen saturation, body temperature, positive inspiratory pressure, systolic blood pressure, and heart rate. Results: There were no significant differences in the anesthetic and physiologic parameters in the AIS and CIS groups. In addition, no differences in demographics, procedural characteristics, or complication rates were found between the cohorts. Conclusion: The AirSeal valveless trocar insufflation system demonstrates comparable intraoperative anesthetic and physiologic outcomes compared to conventional one-way valve insufflation in pediatric laparoscopic pyeloplasty. Certain surgeon-related qualitative metrics are underappreciated in this study, however, including improved visualization with vigorous suctioning and pressure maintenance with frequent instrument exchanges. Surgeon experience may mask the benefits of these characteristics as it pertains to quantitative surgical outcomes such as estimated blood loss, operative time, and perioperative complications.

Effect of a pre-emptive 2-hour session of high-flow nasal oxygen on postoperative oxygenation after major gynaecologic surgery: a randomised clinical trial

BACKGROUND

We aimed at determining whether a 2-h session of high-flow nasal oxygen (HFNO) immediately after extubation improves oxygen exchange after major gynaecological surgery in the Trendelenburg position in adult female patients.

METHODS

In this single-centre, open-label, randomised trial, patients who underwent major gynaecological surgery were randomised to HFNO or conventional oxygen treatment with a Venturi mask. The primary outcome was the Pao2/FiO2 ratio after 2 h of treatment. Secondary outcomes included lung ultrasound score, diaphragm thickening fraction, dyspnoea, ventilatory frequency, Paco2, the percentage of patients with impaired gas exchange (Pao2/FiO2 ≤40 kPa) after 2 h of treatment, and postoperative pulmonary complications at 30 days.

RESULTS

A total of 83 patients were included (42 in the HFNO group and 41 in the conventional treatment group). After 2 h of treatment, median (inter-quartile range) Pao2/FiO2 was 52.9 (47.9-65.2) kPa in the HFNO group and 45.7 (36.4 -55.9) kPa in the conventional treatment group (mean difference 8.7 kPa [95% CI: 3.4 to 13.9], P=0.003). The lung ultrasound score was lower in the HFNO group than in the conventional treatment group (9 [6-10] vs 12 [10-14], P<0.001), mostly because of the difference of the score in dorsal areas (7 [6-8] vs 10 [9-10], P<0.001). The percentage of patients with impaired gas exchange was lower in the HFNO group than in the conventional treatment group (5% vs 37%, P<0.001). All other secondary outcomes were not different between groups.

CONCLUSIONS

In patients who underwent major gynaecological surgery, a pre-emptive 2-h session of HFNO after extubation improved postoperative oxygen exchange and reduced atelectasis compared with a conventional oxygen treatment strategy.

CLINICAL TRIAL REGISTRATION

NCT04566419.

Automated control for investigation of the insufflation-ventilation interaction in experimental laparoscopy

In laparoscopic surgery the abdominal cavity is insufflated with pressurized carbon dioxide gas to create workspace. This pressure is exerted through the diaphragm onto the lungs, competing with ventilation and hampering it. In clinical practice the difficulty of optimizing this balance can lead to the application of harmfully high pressures. This study set out to create a research platform for the investigation of the complex interaction between insufflation and ventilation in an animal model. The research platform was constructed to incorporate insufflation, ventilation and relevant hemodynamic monitoring devices, controlling insufflation and ventilation from a central computer. The core of the applied methodology is the fixation of physiological parameters by applying closed-loop control of specific ventilation parameters. For accurate volumetric measurements the research platform can be used in a CT scanner. An algorithm was designed to keep blood carbon dioxide and oxygen values stable, minimizing the effect of fluctuations on vascular tone and hemodynamics. This design allowed stepwise adjustment of insufflation pressure to measure the effects on ventilation and circulation. A pilot experiment in a porcine model demonstrated adequate platform performance. The developed research platform and protocol automation have the potential to increase translatability and repeatability of animal experiments on the biomechanical interactions between insufflation and ventilation.

Force-based control strategy for a collaborative robotic camera holder in laparoscopic surgery using pivoting motion

Introduction: Laparoscopic surgery often relies on a fixed Remote Center of Motion (RCM) for robot mobility control, which assumes that the patient's abdominal walls are immobile. However, this assumption is inaccurate, especially in collaborative surgical environments. In this paper, we present a force-based strategy for the mobility of a robotic camera-holder system for laparoscopic surgery based on a pivoting motion. This strategy re-conceptualizes the conventional mobility control paradigm of surgical robotics. Methods: The proposed strategy involves direct control of the Tool Center Point's (TCP) position and orientation without any constraints associated with the spatial position of the incision. It is based on pivoting motions to minimize contact forces between the abdominal walls and the laparoscope. The control directly relates the measured force and angular velocity of the laparoscope, resulting in the reallocation of the trocar, whose position becomes a consequence of the natural accommodation allowed by this pivoting. Results: The effectiveness and safety of the proposed control were evaluated through a series of experiments. The experiments showed that the control was able to minimize an external force of 9 N to ±0.2 N in 0.7 s and reduce it to 2 N in just 0.3 s. Furthermore, the camera was able to track a region of interest by displacing the TCP as desired, leveraging the strategy's property that dynamically constrains its orientation. Discussion: The proposed control strategy has proven to be effective minimizing the risk caused by sudden high forces resulting from accidents and maintaining the field of view despite any movements in the surgical environment, such as physiological movements of the patient or undesired movements of other surgical instruments. This control strategy can be implemented for laparoscopic robots without mechanical RCMs, as well as commercial collaborative robots, thereby improving the safety of surgical interventions in collaborative environments.

Cardiorespiratory effects of different intraabdominal pressures in sheep: An experimental study

Increased intraabdominal pressure (IAP) during laparoscopy can reduce venous return, but changes in respiratory system mechanics and their effect in left cardiac function are not well documented. This study evaluated the effects of different IAPs on respiratory mechanics and cardiac function in 10 healthy nonpregnant adult Santa Ines ewes randomly submitted to a crossover study using different IAPs: 0 mm Hg (G1), 10 mm Hg (G2), 12 mmHg (G3), and 15 mmHg (G4). Animals were anesthetized and mechanically ventilated (VT  = 15 ml/kg; positive end-expiratory pressure = 3 cmH2 O; FiO2  = 1.0). Pneumoperitoneum was induced by Hasson's trocar cannula. Variables were measured at INITIAL (IAP, 0 mmHg) and FINAL time points for each IAP after 1 h. At FINAL, driving airway pressure (ΔP,RS ), and percentage fraction of dead space (Vd/Vt) were higher in G3 and G4 than G1 (p = 0.002, difference in means [MD] 4.60, 95% CI: 7.91-1.28, and p < 0.001, MD 5.4, 95% CI: 8.7-2.0; p = 0.016, MD -9.5, 95% CI: -17.9 to -1.2; and p = 0.027, MD -8.7, 95% CI: -17.1 to -0.4). The ejection fraction and fractional shortening were lower in G3 (p = 0.039, MD -11.38, 95% CI: -0.07--22.68; p = 0.015, MD -13.05, 95% CI: -1.74--24.36) and G4 (p = 0.039, MD -9.94, 95% CI: -0.07 to -19.80; p = 0.015, MD -11.43, 95%CI: -1.57 to -21.30, respectively) than G2. In G3, the maximum pulmonary flow velocity correlated negatively with ΔP,RS (r = -0.740; p = 0.018), and Vd/Vt correlated positively with ΔP,RS (r = 0.738, p = 0.046). At IAP of 12 and 15 mm Hg impaired respiratory system mechanics, reduced left cardiac function and no change in maximum pulmonary artery flow velocity were detected. Therefore, respiratory mechanics should be monitored as an interplay to reduce left cardiac function.

Expiratory high-frequency percussive ventilation: a novel concept for improving gas exchange

Background

Although high-frequency percussive ventilation (HFPV) improves gas exchange, concerns remain about tissue overdistension caused by the oscillations and consequent lung damage. We compared a modified percussive ventilation modality created by superimposing high-frequency oscillations to the conventional ventilation waveform during expiration only (eHFPV) with conventional mechanical ventilation (CMV) and standard HFPV.

Methods

Hypoxia and hypercapnia were induced by decreasing the frequency of CMV in New Zealand White rabbits (n = 10). Following steady-state CMV periods, percussive modalities with oscillations randomly introduced to the entire breathing cycle (HFPV) or to the expiratory phase alone (eHFPV) with varying amplitudes (2 or 4 cmH₂O) and frequencies were used (5 or 10 Hz). The arterial partial pressures of oxygen (PaO₂) and carbon dioxide (PaCO₂) were determined. Volumetric capnography was used to evaluate the ventilation dead space fraction, phase 2 slope, and minute elimination of CO₂. Respiratory mechanics were characterized by forced oscillations.

Results

The use of eHFPV with 5 Hz superimposed oscillation frequency and an amplitude of 4 cmH₂O enhanced gas exchange similar to those observed after HFPV. These improvements in PaO₂ (47.3 ± 5.5 vs. 58.6 ± 7.2 mmHg) and PaCO₂ (54.7 ± 2.3 vs. 50.1 ± 2.9 mmHg) were associated with lower ventilation dead space and capnogram phase 2 slope, as well as enhanced minute CO₂ elimination without altering respiratory mechanics.

Conclusions

These findings demonstrated improved gas exchange using eHFPV as a novel mechanical ventilation modality that combines the benefits of conventional and small-amplitude high-frequency oscillatory ventilation, owing to improved longitudinal gas transport rather than increased lung surface area available for gas exchange.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02215-2.

Assessment of Perioperative Atelectasis Using Lung Ultrasonography in Patients Undergoing Pneumoperitoneum Surgery in the Trendelenburg Position: Aspects of Differences according to Ventilatory Mode

BACKGROUND

During robotic gynecologic pneumoperitoneum surgery in the Trendelenburg position, aeration loss leads to perioperative atelectasis. Recently developed ventilator mode pressure-controlled ventilation volume-guaranteed (PCV-VG) mode could provide adequate ventilation with lower inspiratory pressure compared to volume-controlled ventilation (VCV); we hypothesized that PCV-VG mode may be beneficial in reducing perioperative atelectasis via low tidal volume (V_T) of 6 mL/kg ventilation during robotic gynecologic pneumoperitoneum surgery in the Trendelenburg position. We applied lung ultrasound score (LUS) for detecting perioperative atelectasis. We aimed to compare perioperative atelectasis between VCV and PCV-VG with a low V_T of 6 mL/kg during pneumoperitoneum surgery in the Trendelenburg position using LUS.

METHODS

Patients scheduled for robotic gynecologic surgery were randomly allocated to the VCV (n = 41) or PCV-VG group (n = 41). LUS, ventilatory, and hemodynamic parameters were evaluated at T1 (before induction), T2 (10 minutes after induction in the supine position), T3 (10 minutes after desufflation of CO₂ in the supine position), and T4 (30 minutes after emergence from anesthesia in the recovery room).

RESULTS

Eighty patients (40 with PCV-VG and 40 with VCV) were included. Demographic data showed no significant differences between the groups. The total LUS has changed from baseline to T4, 0.63 (95% confidence interval [CI], 0.32, 0.94) to 1.77 (95% CI, 1.42, 2.21) in the VCV group and 0.86 (95% CI, 0.56, 1.16) to 1.43 (95% CI, 1.08, 1.78) in the PCV-VG group (P = 0.170). In both groups, total LUS increased significantly compared to the baseline values.

CONCLUSION

Using a low V_T of 6 mL/kg during pneumoperitoneum surgery in the Trendelenburg position, our study showed no evidence that PCV-VG ventilation was superior to VCV in terms of perioperative atelectasis.

TRIAL REGISTRATION

Clinical Research Information Service Identifier: KCT0006404.

Lung-protective mechanical ventilation for patients undergoing abdominal laparoscopic surgeries: a randomized controlled trial

Background

Pneumoperitoneum and Trendelenburg position in laparoscopic surgeries could contribute to postoperative pulmonary dysfunction. In recent years, intraoperative lung-protective mechanical ventilation (LPV) has been reportedly able to attenuate ventilator-induced lung injuries (VILI). Our objectives were to test the hypothesis that LPV could improve intraoperative oxygenation function, pulmonary mechanics and early postoperative atelectasis in laparoscopic surgeries.

Methods

In this randomized controlled clinical trial, 62 patients indicated for elective abdominal laparoscopic surgeries with an expected duration of greater than 2 h were randomly assigned to receive either lung-protective ventilation (LPV) with a tidal volume (Vt) of 7 ml kg^− 1 ideal body weight (IBW), 10 cmH₂O positive end-expiratory pressure (PEEP) combined with regular recruitment maneuvers (RMs) or conventional ventilation (CV) with a Vt of 10 ml kg^− 1 IBW, 0 cmH₂O in PEEP and no RMs. The primary endpoints were the changes in the ratio of PaO₂ to FiO₂ (P/F). The secondary endpoints were the differences between the two groups in PaO₂, alveolar-arterial oxygen gradient (A-aO₂), intraoperative pulmonary mechanics and the incidence of atelectasis detected on chest x-ray on the first postoperative day.

Results

In comparison to CV group, the intraoperative P/F and PaO₂ in LPV group were significantly higher while the intraoperative A-aO₂ was clearly lower. C_dyn and C_stat at all the intraoperative time points in LPV group were significantly higher compared to CV group (p < 0.05). There were no differences in the incidence of atelectasis on day one after surgery between the two groups.

Conclusions

Lung protective mechanical ventilation significantly improved intraoperative pulmonary oxygenation function and pulmonary compliance in patients experiencing various abdominal laparoscopic surgeries, but it could not ameliorate early postoperative atelectasis and oxygenation function on the first day after surgery.

Trial registration

https://www.clinicaltrials.gov/identifier: NCT04546932 (09/05/2020).

Comparison of the Effects of Low-flow and Normal-flow Desflurane Anaesthesia on Inflammatory Parameters in Patients Undergoing Laparoscopic Cholecystectomy

Objective

According to previous studies, anaesthesia type has an important effect on immune response. However, there are limited data determining the effect of low-flow and normal-flow desflurane anaesthesia on inflammatory parameters. This study aimed to investigate the effect of low-flow and normal-flow desflurane anaesthesia on inflammatory parameters in patients undergoing laparoscopic cholecystectomy.

Methods

A total of 92 patients who underwent laparoscopic cholecystectomy were retrospectively included in this study. The patients were divided into the following 2 groups according to the type of anaesthesia they received: low-flow desflurane anaesthesia group (fresh gas flow rate: 0.5 L min^-1) and normal-flow desflurane anaesthesia group (fresh gas flow rate: 2 L min^-1). Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were obtained before the procedure and 6 hours after the end of the procedure for all patients.

Results

Although pre-procedural NLR and PLR were similar between the normal-flow and low-flow anaesthesia groups, post-procedural NLR (4.38±2.00 vs. 3.51±1.37, p=0.023) and PLR (144.38±71.04 vs. 120.58±35.35, p=0.037) were significantly higher in the normal-flow anaesthesia group. In addition, compared with pre-procedural values, post-procedural NLR (from 2.31±1.02 to 4.38±2.00, p<0.001) and PLR (from 125.60±50.97 to 144.38±71.04, p=0.017) were significantly increased in the normal-flow anaesthesia group, whereas post-procedural NLR (from 2.88±2.51 to 3.51±1.37, p=0.135) and PLR (from 121.86±42.78 to 120.58±35.35, p=0.847) did not change significantly in the low-flow anaesthesia group.

Conclusion

The study results indicated that postoperative inflammatory response was significantly lower with low-flow desflurane anaesthesia than with normal-flow desflurane anaesthesia.

The use of intraoperative bedside lung ultrasound in optimizing positive end expiratory pressure in obese patients undergoing laparoscopic bariatric surgeries

BACKGROUND

Anesthetic management of patients with obesity undergoing laparoscopic abdominal surgeries requires careful plan for intraoperative mechanical ventilation aiming to avoid lung atelectasis and/or overdistention. There are conflicting data on the optimum positive end expiratory pressure (PEEP) during these surgeries. We hypothesized that lung ultrasound could be used for PEEP titration during laparoscopic surgery.

OBJECTIVE

The purpose of this study is to evaluate the effectiveness of intraoperative individualized lung ultrasound-guided PEEP in obese patients undergoing laparoscopic bariatric surgery on intraoperative partial arterial oxygen tension (PaO₂) and early postoperative pulmonary complications.

METHODS

A randomized controlled trial included 40 adult patients with body mass index (BMI) > 35 kg/m² undergoing laparoscopic bariatric surgery. Patients were randomized into: control group (n = 20) who received PEEP 4 cm.H₂ O and ultrasound-guided group (n = 20) who received individualized lung ultrasound stepwise PEEP. All patients received volume-controlled ventilation with a tidal volume of 6 mL/kg of ideal weight and a fraction of inspired oxygen of .5. The primary outcome was the difference in partial arterial oxygen tension (PaO₂) between the control group and the ultrasound-guided group. The secondary outcomes included the incidence of early postoperative pulmonary atelectasis, respiratory failure, bronchospasm, hypoxia or pneumothorax.

SETTINGS

General surgery operating theatre at Cairo University hospitals.

RESULTS

Ultrasound-guided group showed higher PO₂ after PEEP optimization and postoperatively compared with control group (P = .005, and P = .01 respectively). Also, ultrasound-guided group showed no postoperative complications compared with control group that had 5 cases who developed postoperative pulmonary complications in the form of hypoxia and basal collapse in the first 24 hour postoperatively chest x ray (0% versus 25%, P = .047).

CONCLUSION

In patients with obesity undergoing laparoscopic bariatric surgery, the use of lung ultrasound individualized stepwise PEEP approach improved oxygenation, compliance and reduced the incidence of postoperative pulmonary atelectasis and hypoxia without causing hemodynamic instability.

Mechanical Ventilation Guided by Uncalibrated Esophageal Pressure May Be Potentially Harmful

BACKGROUND

Esophageal balloon calibration was proposed in acute respiratory failure patients to improve esophageal pressure assessment. In a clinical setting characterized by a high variability of abdominal load and intrathoracic pressure (i.e., pelvic robotic surgery), the authors hypothesized that esophageal balloon calibration could improve esophageal pressure measurements. Accordingly, the authors assessed the impact of esophageal balloon calibration compared to conventional uncalibrated approach during pelvic robotic surgery.

METHODS

In 30 adult patients, scheduled for elective pelvic robotic surgery, calibrated end-expiratory and end-inspiratory esophageal pressure, and the associated respiratory variations were obtained at baseline, after pneumoperitoneum-Trendelenburg application, and with positive end-expiratory pressure (PEEP) administration and compared to uncalibrated values measured at 4-ml filling volume, as per manufacturer recommendation. Data are expressed as median and [25th, 75th percentile].

RESULTS

Ninety calibrations were successfully performed. Chest wall elastance worsened with pneumoperitoneum-Trendelenburg and PEEP (19.0 [15.5, 24.6] and 16.7 [11.4, 21.7] cm H2O/l) compared to baseline (8.8 [6.3, 9.8] cm H2O/l; P < 0.0001 for both comparisons). End-expiratory and end-inspiratory calibrated esophageal pressure progressively increased from baseline (3.7 [2.2, 6.0] and 7.7 [5.9, 10.2] cm H2O) to pneumoperitoneum-Trendelenburg (6.2 [3.8, 10.2] and 16.1 [13.1, 20.6] cm H2O; P = 0.014 and P < 0.001) and PEEP (8.8 [7.7, 15.6] and 18.9 [16.3, 22.0] cm H2O; P < 0.0001 vs. baseline for both comparison; P < 0.001 and P = 0.002 vs. pneumoperitoneum-Trendelenburg) and, at each study step, they were persistently lower than uncalibrated esophageal pressure (P < 0.0001 for all comparisons). Overall, difference among uncalibrated and calibrated esophageal pressure was 5.1 [3.8, 8.4] cm H2O at end-expiration and 3.8 [3.0, 6.3] cm H2O at end-inspiration. Uncalibrated esophageal pressure swing was always lower than calibrated one (P < 0.0001 for all comparisons) with a difference of -1.0 [-1.8, -0.4] cm H2O.

CONCLUSIONS

In a clinical setting with variable chest wall mechanics, uncalibrated measurements substantially overestimated absolute values and underestimated respiratory variations of esophageal pressure. Calibration could substantially improve mechanical ventilation guided by esophageal pressure.

Same-day discharge protocol for laparoscopic treatment of adnexal disease: management and acceptance

OBJECTIVE

Develop a 'same-day discharge' setting for laparoscopic treatment of adnexal disease.

SETTING

Preventive Gynecology, European Institute of Oncology, Milan, Italy.

POPULATION

Two hundred patients undergoing laparoscopic procedures.

MATERIAL AND METHODS

Data were retrospectively collected through clinical, surgical and laboratory reports. After discharge patients were contacted by phone and e-mail.

MAIN OUTCOME MEASURES

The rate of discharge, adverse events and readmission was measured. The need for adjunctive care provided by our on-call service or by a primary care physician and the acceptability of the same-day discharge protocol were also investigated.

RESULTS

One hundred and sixty-five patients out of 200 were discharged on the same day. Of the 35 patients hospitalized, the most frequent causes for overnight admission were: uncontrolled pain, surgical length or complexity of the procedure in nine patients, nausea/vomit in four patients. One hundred and one out of 200 patients answered the mailed questionnaire. None of the discharged patients were readmitted. Eighty-five percent of the answering patients evaluated the length of their hospital stay as adequate or moderately adequate. Ninety-two percent of the patients would recommend the day surgery to other patients.

CONCLUSIONS

our experience demonstrates that the same-day discharge protocol for laparoscopic treatment of adnexal disease is safe and acceptable.

Effect of Different Levels of Positive End-Expiratory Pressure (PEEP) on Respiratory Status during Gynecologic Laparoscopy

Background

During gynecologic laparoscopy, pneumoperitoneum, and the position of the patient's head can lead to pathophysiologic changes in cardiovascular and respiratory systems, complicating the management of anesthesia in these patients. One of the strategies for improving the respiratory status of patients undergoing laparoscopy is the use of Positive End-Expiratory Pressure (PEEP).

Objectives

This study aimed to evaluate the effect of different levels of PEEP on the respiratory status of patients undergoing gynecologic laparoscopy.

Methods

In this clinical trial, 60 patients with ASA I were randomly assigned to three groups to control anesthesia: ZEEP (PEEP 0 cmH₂O; 20 cases), PEEP₅ (PEEP 5 cmH₂O; 20 cases), and PEEP₁₀ (PEEP 10 cmH₂O; 20 cases). Respiratory and hemodynamic variables of patients were compared before general anesthetic induction and immediately after CO₂ insufflation at intervals of 5, 10, 20, 30, and 60 min and the end of the operation in the three study groups.

Results

The PEEP application improved pH, PaCO₂, and PaO₂ levels at the end of pneumoperitoneum compared to baseline when compared with the non-use of PEEP (ZEEP group). Also, the frequency of dysrhythmia in the use of PEEP in controlled ventilation was significantly lower in patients with PEEP₁₀ (P < 0.05). The application of PEEP₅ resulted in similar effects to PEEP₁₀ in the levels of respiratory variables.

Conclusions

The PEEP application is associated with improved arterial blood gas in patients with gynecologic laparoscopy. The use of PEEP₁₀ has a greater effect on the improvement of respiratory parameters and complications of pneumoperitoneum.

Intraabdominal Pressure Targeted Positive End-expiratory Pressure during Laparoscopic Surgery: An Open-label, Nonrandomized, Crossover, Clinical Trial

BACKGROUND

Pneumoperitoneum for laparoscopic surgery is associated with a rise of driving pressure. The authors aimed to assess the effects of positive end-expiratory pressure (PEEP) on driving pressure at varying intraabdominal pressure levels. It was hypothesized that PEEP attenuates pneumoperitoneum-related rises in driving pressure.

METHODS

Open-label, nonrandomized, crossover, clinical trial in patients undergoing laparoscopic cholecystectomy. "Targeted PEEP" (2 cm H2O above intraabdominal pressure) was compared with "standard PEEP" (5 cm H2O), with respect to the transpulmonary and respiratory system driving pressure at three predefined intraabdominal pressure levels, and each patient was ventilated with two levels of PEEP at the three intraabdominal pressure levels in the same sequence. The primary outcome was the difference in transpulmonary driving pressure between targeted PEEP and standard PEEP at the three levels of intraabdominal pressure.

RESULTS

Thirty patients were included and analyzed. Targeted PEEP was 10, 14, and 17 cm H2O at intraabdominal pressure of 8, 12, and 15 mmHg, respectively. Compared to standard PEEP, targeted PEEP resulted in lower median transpulmonary driving pressure at intraabdominal pressure of 8 mmHg (7 [5 to 8] vs. 9 [7 to 11] cm H2O; P = 0.010; difference 2 [95% CI 0.5 to 4 cm H2O]); 12 mmHg (7 [4 to 9] vs.10 [7 to 12] cm H2O; P = 0.002; difference 3 [1 to 5] cm H2O); and 15 mmHg (7 [6 to 9] vs.12 [8 to 15] cm H2O; P < 0.001; difference 4 [2 to 6] cm H2O). The effects of targeted PEEP compared to standard PEEP on respiratory system driving pressure were comparable to the effects on transpulmonary driving pressure, though respiratory system driving pressure was higher than transpulmonary driving pressure at all intraabdominal pressure levels.

CONCLUSIONS

Transpulmonary driving pressure rises with an increase in intraabdominal pressure, an effect that can be counterbalanced by targeted PEEP. Future studies have to elucidate which combination of PEEP and intraabdominal pressure is best in term of clinical outcomes.

End-tidal carbon dioxide underestimates plasma carbon dioxide during emergent trauma laparotomy leading to hypoventilation and misguided resuscitation: A Western Trauma Association Multicenter Study

BACKGROUND

End-tidal carbon dioxide (ETCO2) is routinely used during elective surgery to monitor ventilation. The role of ETCO2 monitoring in emergent trauma operations is poorly understood. We hypothesized that ETCO2 values underestimate plasma carbon dioxide (pCO2) values during resuscitation for hemorrhagic shock.

METHODS

Multicenter trial was performed analyzing the correlation between ETCO2 and pCO2 levels.

RESULTS

Two hundred fifty-six patients resulted in 587 matched pairs of ETCO2 and pCO2. Correlation between these two values was very poor with an R of 0.04. 40.2% of patients presented to the operating room acidotic and hypercarbic with a pH less than 7.30 and a pCO2 greater than 45 mm Hg. Correlation was worse in patients that were either acidotic or hypercarbic. Forty-five percent of patients have a difference greater than 10 mm Hg between ETCO2 and pCO2. A pH less than 7.30 was predictive of an ETCO2 to pCO2 difference greater than 10 mm Hg. A difference greater than 10 mm Hg was predictive of mortality independent of confounders.

CONCLUSION

Nearly one half (45%) of patients were found to have an ETCO2 level greater than 10 mm Hg discordant from their PCO2 level. Reliance on the discordant values may have contributed to the 40% of patients in the operating room that were both acidotic and hypercarbic. Early blood gas analysis is warranted, and a lower early goal of ETCO2 should be considered.

LEVEL OF EVIDENCE

Therapeutic, level IV.

Effects of intra-operative positive end-expiratory pressure setting guided by oesophageal pressure measurement on oxygenation and respiratory mechanics during laparoscopic gynaecological surgery: A randomised controlled trial

BACKGROUND

The creation of pneumoperitoneum during laparoscopic surgery can lead to adverse effects on the respiratory system. Positive end-expiratory pressure (PEEP) plays an important role in mechanical ventilation during laparoscopic surgery.

OBJECTIVE

To evaluate whether PEEP setting guided by oesophageal pressure (Poeso) measurement would affect oxygenation and respiratory mechanics during laparoscopic gynaecological surgery.

DESIGN

A randomised controlled study.

SETTING

A single-centre trial from March 2018 to June 2018.

PATIENTS

Forty-four adult patients undergoing laparoscopic gynaecological surgery with anticipated duration of surgery more than 2 h.

INTERVENTION

PEEP set according to Poeso measurement (intervention group) versus PEEP constantly set at 5 cmH2O (control group).

MAIN OUTCOME MEASURES

Gas exchange and respiratory mechanics after induction and intubation (T0) and at 15 and 60 min after initiation of pneumoperitoneum (T1 and T2, respectively).

RESULTS

PEEP during pneumoperitoneum was significantly higher in the intervention group than in the control group (T1, 12.5 ± 1.9 vs. 5.0 ± 0.0 cmH2O and T2, 12.4 ± 1.9 vs. 5.0 ± 0.0 cmH2O, both P < 0.001). Partial pressures of oxygen decreased significantly from baseline during pneumoperitoneum in the control group but not in the intervention group. Nevertheless, the changes in partial pressures of oxygen did not differ between groups. Compliance of the respiratory system (CRS) significantly decreased and driving pressure significantly increased during pneumoperitoneum in both groups. However, the changes in CRS and driving pressure were significantly less in the intervention group. Transpulmonary pressure during expiration was maintained in the intervention group while it decreased significantly in the control group.

CONCLUSION

PEEP setting guided by Poeso measurement showed no beneficial effects in terms of oxygenation but respiratory mechanics were better during laparoscopic gynaecological surgery.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03256396.

[Impact of Grade I obesity on respiratory mechanics during video laparoscopic surgery: prospective longitudinal study]

INTRODUCTION AND OBJECTIVES

The association pneumoperitoneum and obesity in video laparoscopy can contribute to pulmonary complications, but has not been well defined in specific groups of obese individuals. We assessed the effects of pneumoperitoneum in respiratory mechanics in Grade I obese compared to non-obese.

METHODS

Prospective study including 20 patients submitted to video laparoscopic cholecystectomy, normal spirometry, divided into non-obese (BMI ≤ 25kg.m^-2) and obese (BMI > 30kg.mg^-2), excluding Grade II and III obese. We measured pulmonary ventilation mechanics data before pneumoperitoneum (baseline), and five, fifteen and thirty minutes after peritoneal insufflation, and fifteen minutes after disinflation (final).

RESULTS

Mean BMI of non-obese was 22.72 ± 1.43kg.m^-2 and of the obese 31.78 ± 1.09kg.m^-2, p < 0.01. Duration of anesthesia and of peritoneal insufflation was similar between groups. Baseline pulmonary compliance (Crs) of the obese (38.3 ± 8.3mL.cm H₂O^-1) was lower than of the non-obese (47.4 ± 5.7mL.cm H₂O^-1), p = 0.01. After insufflation, Crs decreased in both groups and remained even lower in the obese at all moments assessed (GLM p < 0.01). Respiratory system peak pressure and plateau pressure were higher in the obese, albeit variations were similar at moments analyzed (GLM p > 0.05). The same occurred with elastic pressure, higher in the obese at all times (GLM p = 0.04), and resistive pressure showed differences in variations between groups during pneumoperitoneum (GLM p = 0,05).

CONCLUSIONS

Grade I obese presented more changes in pulmonary mechanics than the non-obese during video laparoscopies and the fact requires mechanical ventilation-related care.

Dynamic Tracheobronchial Compression in Steep Trendelenburg Position With Pneumoperitoneum for Robotic-Assisted Cystectomy: A Case Report

Tracheobronchomalacia is a weakness of the trachea and bronchi due to abnormal cartilage and muscular support leading to airway obstruction. We report a case of an adult former smoker without pulmonary symptoms who underwent robotic-assisted laparoscopic cystectomy in the steep Trendelenburg position. After repeated episodes of hypoxemia, bronchoscopic examination revealed collapse of the distal trachea and bronchi, supporting a diagnosis of tracheobronchomalacia. Tracheomalacia is an underdiagnosed condition in patients with a smoking history and may mimic other obstructive diseases. The anesthesiologist should remain vigilant to the possibility of airway collapse in former smokers, specifically in cases of increased intrathoracic pressure.

Pulmonary protection of transcutaneous electrical acupoint stimulation in gynecological laparoscopic surgery: A randomized controlled trial

Laparoscopy is performed worldwide due to its limited side effects and optimal treatment efficacy. However, it also has adverse effects, including atelectasis and ischemia-reperfusion injury, due to CO₂ accumulation during ventilation in a head-down position, which may result in severe disorders and adversely affecting postoperative recovery, prolonging hospitalization. The present study was performed to assess whether transcutaneous electrical acupoint stimulation (TEAS) protects against lung injury occurring during gynecological laparoscopic surgery. Patients were randomly allocated to two groups: Control group (received no stimulation) and TEAS group (patients treated with TEAS on BL13, LI4 and LU5). The mean arterial pressure, heart rate and oxygen saturation were recorded at the time-points of arriving in the operating room (T₀), immediately prior to induction of the pneumoperitoneum (T₁), immediately after the end of pneumoperitoneum (T₂) and on leaving the operating room (T₃). Arterial blood gas analysis was performed to record the pH, determine the partial pressure of carbon dioxide and calculate the oxygenation index (OI) at T_0–3. Blood samples were taken from the peripheral vein for determination of the serum concentrations of tumor necrosis factor (TNF)-α and interleukin (IL)-1β at T₀ and T₃. Post-operative pulmonary complications occurring during the first five days after surgery were also recorded. A total of 100 patients were initially enrolled and 80 patients were analysed. The results indicated that the OI in the control group was significantly lower than that in the TEAS group at the T₂ and T₃ time-points. The serum concentrations of TNF-α and IL-1β were significantly increased following surgery, while the extent of these increases was lower in the TEAS group compared with that in the control group. The incidence of post-operative pulmonary complications was significantly lower in the TEAS group. It was therefore indicated that TEAS protect against lung injury as a complication of gynecological laparoscopic surgery. The present study was registered at http://www.clinicaltrials.gov prior to enrollment of the patients (no. NCT02850471).

[Perioperative management for CRS and HIPEC : Anesthesiological aspects]

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are therapeutic options for the treatment of intra-abdominal neoplasms. Following the resection of all visible tumor areas by CRS, microscopic tumor areas are treated with HIPEC. This procedure increases the quality of life and survival. The CRS with HIPEC is a complex surgical procedure in which the mainly younger and often otherwise healthy patients undergo several pathophysiological changes during the operation. The main concern of the anesthesiologist is the massive volume loss, volume shift and metabolic alterations. Patients with a high comorbidity should undergo preoperative optimization to reduce the perioperative morbidity and mortality especially by protracted interventions.

Sudden Airway Collapse After Pneumoperitoneum With Undiagnosed Tracheomalacia in a Morbidly Obese 12-Year-Old Boy Undergoing Laparoscopic Cholecystectomy: A Case Report

Tracheomalacia is characterized by the collapse of the tracheal wall due to the softening of the tracheal cartilage and myoelastic tissues. We describe the case of a 12-year-old morbidly obese boy, without previous medical issues, scheduled for elective laparoscopic cholecystectomy. Immediately after pneumoperitoneum was established, mechanical ventilation could not be performed. Intraoperative exploration with flexible bronchoscopy showed that the tip of the endotracheal tube was nearly occluded by the posterior tracheal wall bulging anteriorly. Anesthesiologists should be aware of undiagnosed tracheomalacia as a cause of sudden airway collapse, even after the airway is secured with an endotracheal tube.

Anesthesia for Pygopagus Conjoined Twins During Single-Twin and Simultaneous Pneumoperitoneum: A Case Report

We present the case of the first stage of separation of 9-month-old pygopagus conjoined twins who demonstrated minimal shared vasculature on preoperative imaging and no cross-sedation or cross-neuromuscular blockade during separate inductions of anesthesia. Laparoscopy was implemented in 1 twin at a time, then in both twins simultaneously. Despite insufflation of a single-twin's abdomen, both twins demonstrated hypercapnia and signs of a concomitant respiratory acidosis because of carbon dioxide diffusion through a shared peritoneal membrane. This is the first documented case of simultaneous laparoscopy-induced pneumoperitoneum in pygopagus conjoined twins.

Regional Lung Recruitability During Pneumoperitoneum Depends on Chest Wall Elastance - A Mechanical and Computed Tomography Analysis in Rats

Background: Laparoscopic surgery with pneumoperitoneum increases respiratory system elastance due to the augmented intra-abdominal pressure. We aim to evaluate to which extent positive end-expiratory pressure (PEEP) is able to counteract abdominal hypertension preventing progressive lung collapse and how rib cage elastance influences PEEP effect. Methods: Forty-four Wistar rats were mechanically ventilated and randomly assigned into three groups: control (CTRL), pneumoperitoneum (PPT) and pneumoperitoneum with restricted rib cage (PPT-RC). A pressure-volume (PV) curve followed by a recruitment maneuver and a decremental PEEP trial were performed in all groups. Thereafter, animals were ventilated using PEEP of 3 and 8 cmH₂O divided into two subgroups used to evaluate respiratory mechanics or computed tomography (CT) images. In 26 rats, we compared respiratory system elastance (E_rs) at the two PEEP levels. In 18 animals, CT images were acquired to calculate total lung volume (TLV), total volume and air volume in six anatomically delimited regions of interest (three along the cephalo-caudal and three along the ventro-dorsal axes). Results: PEEP of minimal E_rs was similar in CTRL and PPT groups (3.8 ± 0.45 and 3.5 ± 3.89 cmH₂O, respectively) and differed from PPT-RC group (9.8 ± 0.63 cmH₂O). Chest restriction determined a right- and downward shift of the PV curve, increased E_rs and diminished TLV and lung aeration. Increasing PEEP augmented TLV in CTRL group (11.8 ± 1.3 to 13.6 ± 2 ml, p < 0.05), and relative air content in the apex of PPT group (3.5 ± 1.4 to 4.6 ± 1.4% TLV, p < 0.03) and in the middle zones in PPT-RC group (21.4 ± 1.9 to 25.3 ± 2.1% TLV cephalo-caudally and 18.1 ± 4.3 to 22.0 ± 3.3% TLV ventro-dorsally, p < 0.005). Conclusion: Regional lung recruitment potential during pneumoperitoneum depends on rib cage elastance, reinforcing the concept of PEEP individualization according to the patient's condition.

Neuromuscular blockade of atracurium in permissive hypercapnic versus normocapnic swine undergoing laparoscopy

Neuromuscular blocking agents (NMBAs) are commonly used in experimental laparoscopy in swine undergoing carbon dioxide pneumoperitoneum. Hypercapnia may be present and may prolong NMBAs’ pharmacologic activity. The aim of this study is to evaluate the effect of permissive hypercapnia on the neuromuscular blockade of atracurium in swine. Six Large White swine weighing 30.5 ± 1.6 kg were sedated with intramuscular ketamine and medetomidine, after which anaesthesia was induced with propofol and maintained with sevoflurane. Atracurium 0.4 mg/kg was administered intravenously and the neuromuscular block monitored by acceleromyography during normocapnic and hypercapnic conditions (PaCO₂ range 35–45 mmHg and 60–70 mmHg, respectively). Onset time and time to reach a train of four ratio (TOFR) of 0.7 and 0.9 were recorded. Cardiorespiratory parameters, electrolytes and acid-base status were measured under both conditions. Onset time was similar between the two conditions. Time to reach a TOFR of 0.7 and 0.9 (duration of the neuromuscular block) was longer in hypercapnic compared to normocapnic animals being 1325 ± 300 vs 855 ±111 (p = 0.002) and 1823 ± 434 vs 1218 ± 210 seconds (p = 0.005), respectively. Three hypercapnic swine had a TOF count of 2 and 1 instead of a count of 4 with fade. Permissive hypercapnia was associated with a decrease in pH from 7.444 ± 0.039 to 7.257 ± 0.025 (p < 0.001). No differences were observed for heart rate, end-tidal concentration of sevoflurane, body temperature and arterial haemoglobin saturation. Nonetheless, hypercapnic swine had a statistically significant increase in mean arterial pressure (p = 0.020) and plasma potassium concentration (p = 0.003). The values of PaCO₂ achieved during hypercapnia were well tolerated in swine undergoing CO₂ pneumoperitoneum for laparoscopy. Permissive hypercapnia increased the duration of the atracurium effect and caused an increase in the intensity of the neuromuscular block in few swine.

[Perioperative management for CRS and HIPEC : Anesthesiological aspects]

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are therapeutic options for the treatment of intra-abdominal neoplasms. Following the resection of all visible tumor areas by CRS, microscopic tumor areas are treated with HIPEC. This procedure increases the quality of life and survival. The CRS with HIPEC is a complex surgical procedure in which the mainly younger and often otherwise healthy patients undergo several pathophysiological changes during the operation. The main concern of the anesthesiologist is the massive volume loss, volume shift and metabolic alterations. Patients with a high comorbidity should undergo preoperative optimization to reduce the perioperative morbidity and mortality especially by protracted interventions.

Intraoperative Ventilation Patterns in Morbidly Obese Patients Undergoing Laparoscopic Bariatric Surgery

Background: The purpose of this study was to examine ventilation patterns, including tidal volume (TV) and positive end-expiratory pressure (PEEP) selection in morbidly obese patients undergoing laparoscopic Roux-en-Y gastric bypass or laparoscopic sleeve gastrectomy. Methods: Intraoperative ventilation data, including TV and PEEP, were abstracted from the electronic anesthesia record (Metavision) at Brigham and Women's Hospital. Ideal body weight (IBW) was calculated using the Devine formula, and TV per kg IBW was calculated for each patient. Results: The mean TV delivered per kg IBW was 7.35 ± 1.07 mL/kg, and 24% (281/1186) of patients received TVs of >8 mL/kg IBW. The median PEEP applied was 5.5 ± 0.6 cmH₂O, and 87% (1035/1186) of patients received PEEP >0 cmH₂O. There was significant variation in both TV and PEEP selection. Conclusions: The significant variation in TV per kg IBW as well as in PEEP values at our institution may reflect the lack of well-established guidelines for intraoperative ventilation. Many patients in this study received inappropriately large TVs (>8 mL/kg IBW), which may be due to calculation of TVs based on total body weight rather than IBW. Patients of shorter stature and higher body mass index appear to be at higher risk for ventilation with inappropriately large TVs.

Joint consensus on abdominal robotic surgery and anesthesia from a task force of the SIAARTI and SIC

Minimally invasive surgical procedures have revolutionized the world of surgery in the past decades. While laparoscopy, the first minimally invasive surgical technique to be developed, is widely used and has been addressed by several guidelines and recommendations, the implementation of robotic-assisted surgery is still hindered by the lack of consensus documents that support healthcare professionals in the management of this novel surgical procedure. Here we summarize the available evidence and provide expert opinion aimed at improving the implementation and resolution of issues derived from robotic abdominal surgery procedures. A joint task force of Italian surgeons, anesthesiologists and clinical epidemiologists reviewed the available evidence on robotic abdominal surgery. Recommendations were graded according to the strength of evidence. Statements and recommendations are provided for general issues regarding robotic abdominal surgery, operating theatre organization, preoperative patient assessment and preparation, intraoperative management, and postoperative procedures and discharge. The consensus document provides evidence-based recommendations and expert statements aimed at improving the implementation and management of robotic abdominal surgery.

Application of intraoperative lung-protective ventilation varies in accordance with the knowledge of anaesthesiologists: a single-Centre questionnaire study and a retrospective observational study

Background

The benefits of lung-protective ventilation (LPV) with a low tidal volume (6 mL/kg of ideal body weight [IBW]), limited plateau pressure (< 28–30 cm H₂O), and appropriate positive end-expiratory pressure (PEEP) in patients with acute respiratory distress syndrome have become apparent and it is now widely adopted in intensive care units. Recently evidence for LPV in general anaesthesia has been accumulated, but it is not yet generally applied by anaesthesiologists in the operating room.

Methods

This study investigated the perception about intraoperative LPV among 82 anaesthesiologists through a questionnaire survey and identified the differences in ventilator settings according to recognition of lung-protective ventilation. Furthermore, we investigated the changes in the trend for using this form of ventilation during general anaesthesia in the past 10 years.

Results

Anaesthesiologists who had received training in LPV were more knowledgeable about this approach. Anaesthesiologists with knowledge of the concept behind LPV strategies applied a lower tidal volume (median (IQR [range]), 8.2 (8.0–9.2 [7.1–10.3]) vs. 9.2 (9.1–10.1 [7.6–10.1]) mL/kg; p = 0.033) and used PEEP more frequently (69/72 [95.8%] vs. 5/8 [62.5%]; p = 0.012; odds ratio, 13.8 [2.19–86.9]) for laparoscopic surgery than did those without such knowledge. Anaesthesiologists who were able to answer a question related to LPV correctly (respondents who chose ‘height’ to a multiple choice question asking what variables should be considered most important in the initial setting of tidal volume) applied a lower tidal volume in cases of laparoscopic surgery and obese patients. There was an increase in the number of patients receiving LPV (V_T < 10 mL/kgIBW and PEEP ≥5 cm H₂O) between 2004 and 2014 (0/818 [0.0%] vs. 280/818 [34.2%]; p <  0.001).

Conclusions

Our study suggests that the knowledge of LPV is directly related to its implementation, and can explain the increase in LPV use in general anaesthesia. Further studies should assess the impact of using intraoperative LPV on clinical outcomes and should determine the efficacy of education on intraoperative LPV implementation.

Electronic supplementary material

The online version of this article (10.1186/s12871-018-0495-7) contains supplementary material, which is available to authorized users.

Ultrasound detection of diaphragm position in the region for lung monitoring by electrical impedance tomography during laparoscopy

BACKGROUND AND AIMS

During laparoscopic surgery, a capnoperitoneum is created to optimize the operating space for surgeons. One effect of this is abdominal pressure which alters the physiological thoraco-abdominal configuration and pushes the diaphragm and lungs cranially. Since the lung image acquired by electrical impedance tomography (EIT) depends on the conditions within the thorax and abdomen, it is crucial to know the diaphragm position to determine the effect of diaphragm shift on EIT thorax image.

METHODS

The presence of diaphragm in the region of EIT measurement was determined by ultrasound in 20 patients undergoing laparoscopic surgery. Data were obtained in the supine position during spontaneous breathing in a mechanically ventilated patient under general anesthesia with muscle relaxation and in a mechanically ventilated patient under general anesthesia with muscle relaxation during capnoperitoneum.

RESULTS

The diaphragm was shifted cranially during capnoperitoneum. The diaphragm detection rate rose by 10% during capnoperitoneum at the fifth intercostal space, from 55% to 65% and by 10% from 0% at mid-sternal level compared to mechanical ventilation without capnoperitoneum.

CONCLUSION

The diaphragm was detected in the area contributing to the creation of the thoracic EIT image. Considering the cranial shift of diaphragm caused by excessive intra-abdominal pressure, the impedance changes in the abdomen and the principle of EIT, we assume there could be a significant impact on EIT image of the thorax acquired during capnoperitoneum. For this reason, for lung monitoring using EIT during capnoperitoneum, the manufacturer's recommendation for electrode belt position is not appropriate. The study was registered in ClinicalTrials.gov with an identifier NCT03038061.

The care dependency of patients after laparoscopic abdominal surgery and associated factors in China

PURPOSE

The outcome after laparoscopic surgery is dependent on self-care behaviors. Whether or not the patients after laparoscopic abdominal surgery in China are care-dependent is still unclear. Thus, the studies try to analyze influence factors of care dependence on patients with laparoscopic abdominal surgery, to provide reference for personalized care for the patient.

METHODS

In our study, two hundreds and forty-two cases were selected and investigated by using the exercise of self-care agency scale and care dependency scale. And correlation analyses between care dependency and self-care agency, age or hospital stay duration was made by Spearman correlation analysis. The analysis of associated factors was made by multivariable linear regression model.

RESULTS

The mean age of participants is 42.12±12.67 (ranged from 18 to 73years), and 134 patients (55.37%) in the study were older than 50years. Among the 242 participants, 59.09% is male. Our data found that the average self-care agency score was 115.72±30.13. And 64.88% participates are in the median level of self-care agency. Care dependency correlated with self-care agency (r=-0.85, P=0.009), age (r=-0.71, P=0.001) and hospital stay duration (r=-0.69, P=0.003) negatively. The linear regression was found between gender, age, educational level, days of hospital stay and care dependency. The model is care dependency=99.533+5.02×(gender)-0.795×(age)+0.512×(educational level)-0.239×(days of hospital stay).

CONCLUSION

Patients after laparoscopic surgery take notice of self-care. Gender, age, educational level and days of hospital stay affect care dependence.

Comparison of Arterial Oxygenation Following Head-Down and Head-Up Laparoscopic Surgery

BACKGROUND

Regarding the role of gas entry in abdomen and cardiorespiratory effects, the ability of anesthesiologists would be challenged in laparoscopic surgeries. Considering few studies in this area and the relevance of the subject, this study was performed to compare the arterial oxygen alterations before operation in comparison with after surgery between laparoscopic cholecystectomy and ovarian cystectomy.

METHODS

In this prospective cohort, 70 consecutive women aged from 20 to 60 years who were candidate for laparoscopic cholecystectomy (n = 35) and ovarian cystectomy (n = 35) with reverse (20 degrees) and direct (30 degrees) Trendelenburg positions, respectively, with ASA class I or II were enrolled. After intubation and before operation, for the first time, the arterial blood gas from radial artery in supine position was obtained for laboratory assessment. Then, the second blood sample was collected from radial artery in supine position and sent to the lab to be assessed with the same device after 30 minutes from surgery termination. The measured variables from arterial blood gas were arterial partial pressure of oxygen (PaO2) and Oxygen saturation (SpO2) alterations.

RESULTS

Total PaO2 was higher in the first measurement. The higher values of PaO2 in cholecystectomy (upward) than in ovarian cystectomy (downward) were not significant in univariate (P = 0.060) and multivariate analysis (P = 0.654). Furthermore, higher values of SpO2 in cholecystectomy (upward) than in ovarian cystectomy (downward) were not significant in univariate (P = 0.412) and multivariate analysis (P = 0.984).

CONCLUSIONS

In general, based on the results of this study, the values of PaO2 in cholecystectomy (upward) were not significantly higher than the values in cystectomy (downward) in laparoscopic surgeries when measured 30 minutes after surgery.

Effects of positive end-expiratory pressure on intracranial pressure during pneumoperitoneum and Trendelenburg position in a porcine mode

Background/aim: This study was undertaken to evaluate the effects of positive end-expiratory pressure (PEEP) levels on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) and to determine the appropriate PEEP level during steep Trendelenburg position combined with pneumoperitoneum.Materials and methods: Ten pigs were included in this study. Pneumoperitoneum and Trendelenburg position were maintained and PEEP titration was initiated. Arterial pressure, heart rate, arterial blood gas, ICP, and CPP were recorded at the following time points: baseline (T0), 30 min after positioning and pneumoperitoneum (T1), PEEP 5 (T2), PEEP 10 (T3), PEEP 15 (T4), and PEEP 20 (T5).Results: MAP significantly increased at T1 compared to T0 and decreased at T4 and T5 compared to T1. ICP was 9.5 mmHg and CPP was 69.3 mmHg at T0. CO2 insufflation and steep Trendelenburg position did not cause any significant difference in ICP and CPP. ICP increased and CPP decreased significantly at T4 and T5 compared to both T0 and T1. PaO2 and PaO2/FiO2 decreased significantly at T1 and T2 compared to T0, while both increased significantly at T3, T4, and T5 compared to T1.Conclusion: PEEP of 10 cmH2O was effective for providing oxygenation while preserving hemodynamic stability, ICP, and CPP in this model.

Intraoperative low tidal volume ventilation strategy has no benefits during laparoscopic cholecystectomy

Background and Aims:

Benefits of intraoperative low tidal volume ventilation during laparoscopic surgery are not conclusively proven, even though its advantages were seen in other situations with intraoperative respiratory compromise such as one-lung ventilation. The present study compared the efficacy of intraoperative low tidal volume ventilatory strategy (6 ml/kg along with positive end-expiratory pressure [PEEP] of 10 cmH₂O) versus one with higher tidal volume (10 ml/kg with no PEEP) on various clinical parameters and plasma levels of interleukin (IL)-6 in patients undergoing laparoscopic cholecystectomy.

Material and Methods:

A total of 58 adult patients with American Society of Anesthesiologists physical status I or II, undergoing laparoscopic cholecystectomy were randomized to receive the low or higher tidal volume strategy as above (n = 29 each). The primary outcome measure was postoperative PaO₂. Systemic levels of IL-6 along with clinical indices of intraoperative gas exchange, pulmonary mechanics, and hemodynamic consequences were measured as secondary outcome measures.

Results:

There was no statistically significant difference in oxygenation; intraoperative dynamic compliance, peak airway pressures, or hemodynamic parameters, or the IL-6 levels between the two groups (P > 0.05). Low tidal volume strategy was associated with significantly higher mean airway pressure, lower airway resistance, greater respiratory rates, and albeit clinically similar, higher PaCO₂and lower pH (P < 0.05).

Conclusion:

Strategy using 6 ml/kg tidal volume along with 10 cmH₂O of PEEP was not associated with any significant improvement in gas exchange, hemodynamic parameters, or systemic inflammatory response over ventilation with 10 ml/kg volume without PEEP during laparoscopic cholecystectomy.

Comparison between supraglottic airway devices and endotracheal tubes in patients undergoing laparoscopic surgery: A systematic review and meta-analysis

BACKGROUND

Comparisons between the efficacies of supraglottic airway devices (SGAs) and endotracheal tubes (ETTs) in patients undergoing laparoscopic surgeries have yielded conflicting results. Therefore, in this meta-analysis, we compared the clinical performance and incidence of complications between SGAs and ETT intubation in laparoscopic surgery.

METHODS

A comprehensive search was conducted using MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and Google Scholar to identify randomized controlled trials that compared SGAs with ETTs in laparoscopic surgery.

RESULTS

In total, 1433 patients from 17 studies were included in the final analysis. SGAs and ETTs showed no difference in insertion success rate on the first attempt (relative risk [RR] 1.01, 95% confidence interval [CI] 0.99-1.03), insertion time (standardized mean difference 1.57, 95% CI -3.74 to 0.61), and oropharyngeal leak pressure (OLP) (mean difference -2.54, 95% CI -7.59 to 2.50). The incidence of desaturation (RR 3.65, 95% CI 1.39-9.62), gastric insufflations (RR 0.90, 95% CI 0.48-1.71), regurgitation (RR 0.98, 95% CI 0.02-49.13), and aspiration (RR 0.99, 95% CI 0.01-78.4) also showed no intergroup differences. However, the incidence of laryngospasm (RR 3.12, 95% CI 1.29-7.52), cough at removal (RR 6.68, 95% CI 4.70-9.48), dysphagia (RR 1.47, 95% CI 1.12-1.95) or dysphonia (RR 4.41, 95% CI 1.25-15.55), sore throat (RR 1.60, 95% CI 1.33-1.93), and hoarseness (RR 1.53, 95% CI 1.29-1.81) was higher in the ETT group than in the SGA group.

CONCLUSIONS

The incidence of laryngospasm, cough at removal, dysphagia or dysphonia, sore throat, and hoarseness were higher in the ETT group than in the SGA group. However, the groups showed no differences in the rate of insertion success on the first attempt, insertion time, OLP, and other complications. Therefore, SGAs might be clinically more useful as effective airways in laparoscopic surgery.

Effects of Low-Flow Sevoflurane Anesthesia on Pulmonary Functions in Patients Undergoing Laparoscopic Abdominal Surgery

Objective. The aim of this prospective, randomized study was to investigate the effects of low-flow sevoflurane anesthesia on the pulmonary functions in patients undergoing laparoscopic cholecystectomy. Methods. Sixty American Society of Anesthesiologists (ASA) physical status classes I and II patients scheduled for elective laparoscopic cholecystectomy were included in the study. Patients were randomly allocated to two study groups: high-flow sevoflurane anesthesia group (Group H, n = 30) and low-flow sevoflurane anesthesia group (Group L, n = 30). The fresh gas flow rate was of 4 L/min in high-flow sevoflurane anesthesia group and 1 L/min in low-flow sevoflurane anesthesia group. Heart rate (HR), mean arterial blood pressure (MABP), peripheral oxygen saturation (SpO₂), and end-tidal carbon dioxide concentration (ETCO₂) were recorded. Pulmonary function tests were performed before and 2, 8, and 24 hours after surgery. Results. There was no significant difference between the two groups in terms of HR, MABP, SpO₂, and ETCO₂. Pulmonary function test results were similar in both groups at all measurement times. Conclusions. The effects of low-flow sevoflurane anesthesia on pulmonary functions are comparable to high-flow sevoflurane anesthesia in patients undergoing laparoscopic cholecystectomy.

Videoscopic ilioinguinal lymphadenectomy for groin lymph node metastases from melanoma

BACKGROUND

Groin lymph node dissection for melanoma is burdened by high postoperative morbidity. Videoscopic lymphadenectomy may lower the incidence of complications, including infection, dehiscence and lymphoedema. This pilot study aimed to investigate the feasibility and postoperative outcomes of videoscopic ilioinguinal lymphadenectomy in patients with inguinal nodal melanoma metastases.

METHODS

Patients with inguinal nodal metastases, with either a positive sentinel lymph node biopsy or clinically positive nodes from melanoma, were enrolled. Inguinal dissection was performed via three ports. Iliac dissection was obtained through a preperitoneal access. Intraoperative and postoperative data were collected.

RESULTS

Of 23 patients selected for 24 procedures, four needed conversion to an open procedure. Median duration of surgery was 270 (i.q.r. 245-300) min. Wound-related postoperative complications occurred in four patients, although only one needed further intervention. The median number of excised lymph nodes was 21 (i.q.r. 15-25). After a median follow-up of 18 months, regional lymph node recurrence was observed in two patients.

CONCLUSION

Videoscopic ilioinguinal lymphadenectomy for melanoma groin lymph node metastases is technically feasible, safe, and associated with acceptable morbidity and oncological outcome.

Anaesthetic Considerations in the Perioperative Management of Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy has emerged as one of the primary modalities of treatment of diffuse peritoneal malignancies. It is a complex surgical procedure with the patients facing major and potentially life threatening alterations of haemodynamic, respiratory, metabolic and thermal balance with significant fluid losses and the perioperative management is challenging for anaesthesiologists and intensive care physicians. Though the alterations are short lived, these patients require advanced organ function monitoring and support perioperatively. The anaesthesiologist is involved in the management of haemodynamics, respiratory function, coagulation, haematologic parameters, fluid balance, thermal variations, and metabolic and nutritional support perioperatively. The chemotherapy instillate used are known to cause nephrotoxicity, cardiotoxicity, dyselectrolytemia and lactic acidosis. The preoperative polypharmacy for pain control, previous surgery and/or chemotherapy, malnourished status secondary to feeding problems and tumour wasting syndrome make the task all the more challenging. The anaesthesiologist also needs to consider the perioperative care from a quality of life perspective and proper preoperative counselling is important. The present overview summarizes the challenges faced by the anaesthesiologist regarding the pathophysiological alterations during the Cytoreductive surgery and Hyperthermic intraperitoneal chemotherapy in the preoperative, intraoperative and postoperative periods.