The effect of pneumoperitoneum and Trendelenburg position on respiratory mechanics during pelviscopic surgery

Anesthesiological and surgical perspectives on using 8 mmHg versus 12 mmHg pneumoperitoneum pressures during robotic radical prostatectomy: Results of a prospective randomized study

BACKGROUND

This study aims to compare the effects of 8 mmHg and 12 mmHg pneumoperitoneum (PNP) pressures on operative, postoperative, and anesthesiological parameters in robot-assisted laparoscopic radical prostatectomy (RARP).

METHODS

In this prospective study, 43 patients undergoing RARP performed by a single experienced surgeon were randomly assigned to either the low-pressure group (8 mmHg - Group I) or the standard-pressure group (12 mmHg - Group II). We evaluated the operative and postoperative parameters from both urological and anesthesiological perspectives. All patients were treated using the AirSeal® insufflation system.

RESULTS

No statistically significant differences were observed between the groups in terms of console time, estimated blood loss, time to first flatus, or hospital length of stay. PNP was increased due to bleeding in six patients in the 8 mmHg group and two patients in the 12 mmHg group. Except for the heart rate measured five minutes after the initial incision, there were no observed differences between the groups in terms of blood pressure, ventilation, and administered medications. The heart rate was significantly lower in Group I (54.4 vs. 68.8, p=0.006). Additionally, during the surgery, the number of manipulations performed by the anesthesiologists, including drug administrations and ventilator management, was significantly lower in Group I (6.1 vs. 9.6, p=0.041).

CONCLUSION

In RARP, while the 8 mmHg PNP pressure does not demonstrate differences in operative parameters compared to the 12 mmHg pressure, it offers the advantage of requiring fewer anesthetic interventions, thus minimizing the impact on cardiovascular and respiratory systems.

Comparison of tracheal versus esophageal temperatures during laparoscopic surgery

PURPOSE

Recently, endotracheal tubes with an embedded temperature sensor in the inner surface of the tube cuff (temperature tracheal tubes) have been developed. We sought to assess whether temperature tracheal tubes show a good agreement with esophageal temperature probes during surgery.

METHODS

We enrolled 40 patients who underwent laparoscopic surgery in an observational study. The tracheas of all patients were intubated with a temperature tracheal tube, and an esophageal temperature probe was inserted into the esophagus. Tracheal and esophageal temperatures were recorded at 15-min intervals until the end of surgery. Temperatures from both devices were analyzed using Bland-Altman analysis, four-quadrant plots, and polar plots.

RESULTS

We analyzed 261 data points from 36 patients. Temperatures ranges were 34.2 °C to 36.6 °C for the tracheal temperature tube and 34.7 °C to 37.2 °C for the esophageal temperature probe. Bland-Altman analysis showed an acceptable agreement between the two devices, with an overall mean bias (95% limit of agreement) of -0.3 °C (-0.8 °C to 0.1 °C) and a percentage error of 3%; the trending ability (temperature changes over time) between the two devices showed a concordance rate of 94% in four-quadrant plot (cut-off ≥ 92%), but this was higher than the acceptable mean angular bias of 177° (cut-off <  ± 5°) and radial limits of agreement of 52° (cut-off <  ± 30°) in the polar plot. Bronchoscopy during extubation and patient interviews at six hours postoperatively revealed no serious injuries related to the use of the temperature tracheal tube.

CONCLUSION

The temperature tracheal tube showed an acceptable overall mean bias of -0.3 °C and a percentage error of 3%, but incompatible trending ability with the esophageal temperature probe.

STUDY REGISTRATION

cris.nih.go.kr (KCT0007265); 22 April 2022.

Role of oxygen reserve index monitoring in patients undergoing robot-assisted radical prostatectomy: a retrospective study

PURPOSE

Robot-assisted radical prostatectomy (RARP) is a common surgical procedure for the treatment of prostate cancer. Although beneficial, it can lead to intraoperative hypoxia due to high-pressure pneumoperitoneum and Trendelenburg position. This study explored the use of oxygen reserve index (ORi) to monitor and predict hypoxia during RARP.

METHODS

A retrospective analysis was conducted on 329 patients who underwent RARP at the Seoul National University Bundang Hospital between July 2021 and March 2023. Various pre- and intraoperative variables were collected, including ORi values. The relationship between ORi values and hypoxia occurrence was assessed using receiver operating characteristic curves and logistic regression analysis.

RESULTS

Intraoperative hypoxia occurred in 18.8% of the patients. The receiver operating characteristic curve showed a satisfactory area under the curve of 0.762, with the ideal ORi cut-off value for predicting hypoxia set at 0.16. Sensitivity and specificity were 64.5% and 75.7%, respectively. An ORi value of < 0.16 and a higher body mass index were identified as independent risk factors of hypoxia during RARP.

CONCLUSIONS

ORi monitoring provides a non-invasive approach to predict intraoperative hypoxia during RARP, enabling early management. Additionally, the significant relationship between a higher body mass index and hypoxia underscores the importance of individualized patient assessment.

Tips and tricks in gynaecological robotic surgery

It was the dawn of a new era for robotic surgery when the Food and Drug Administration (FDA) approved da Vinci robotic surgical system for general laparoscopic procedures in 2000. The surgical practice saw a transformative breakthrough towards minimally invasive approach with the ever-increasing uptake of advanced robots proven to benefit patients and surgeons in various ways. However, these innovative machines only complement and enhance a surgeon's operating skills, and with such privilege come responsibilities and new challenges. Heavy reliance on such advanced devices while operating on humans necessitates thorough training and supervision to ensure safe and efficient applications. It is the surgeon's responsibility to direct the procedure constantly and lead other team members who assist during the surgery. In this chapter, we provide miscellaneous tips and tricks that can help beginners navigate through robotic surgery with more confidence and enthusiasm.

Machine learning model for predicting immediate postoperative desaturation using spirometry signal data

Postoperative desaturation is a common post-surgery pulmonary complication. The real-time prediction of postoperative desaturation can become a preventive measure, and real-time changes in spirometry data can provide valuable information on respiratory mechanics. However, there is a lack of related research, specifically on using spirometry signals as inputs to machine learning (ML) models. We developed an ML model and postoperative desaturation prediction index (DPI) by analyzing intraoperative spirometry signals in patients undergoing laparoscopic surgery. We analyzed spirometry data from patients who underwent laparoscopic, robot-assisted gynecologic, or urologic surgery, identifying postoperative desaturation as a peripheral arterial oxygen saturation level below 95%, despite facial oxygen mask usage. We fitted the ML model on two separate datasets collected during different periods. (Datasets A and B). Dataset A (Normal 133, Desaturation 74) was used for the entire experimental process, including ML model fitting, statistical analysis, and DPI determination. Dataset B (Normal 20, Desaturation 4) was only used for verify the ML model and DPI. Four feature categories-signal property, inter-/intra-position correlation, peak value/interval variability, and demographics-were incorporated into the ML models via filter and wrapper feature selection methods. In experiments, the ML model achieved an adequate predictive capacity for postoperative desaturation, and the performance of the DPI was unbiased.

Ultrasonographic evaluation of diaphragmatic excursion changes after major laparoscopic surgeries in the Trendelenburg position under general anaesthesia: A prospective observational study

Background and Aims

Laparoscopic surgeries result in increased intra abdominal pressure and cephalad displacement of the diaphragm. The Trendelenburg position can augment these respiratory changes. The primary objective of this study was to compare diaphragmatic excursions before and after a major laparoscopic pelvic surgery under general anaesthesia in the Trendelenburg position using ultrasonography (USG).

Methods

This prospective observational study included 90 patients of either gender, aged 20-60 years, with American Society of Anesthesiologists physical status I/II. M-mode USG was used to assess diaphragm inspiratory amplitude (DIA) before induction of anaesthesia and 10 minutes after tracheal extubation. Factors such as age, gender, body mass index, positive end-expiratory pressure (PEEP), pain, peak airway pressures, duration of pneumoperitoneum, duration and degree of Trendelenburg position and duration of anaesthesia were recorded. Pearson's correlation and multiple linear regression were used to analyse the factors affecting change in DIA (ΔDIA).

Results

The mean difference (95% confidence interval (CI)) of measured DIA was 0.70 (0.598-0.809), P < 0.001. ΔDIA had a weak positive significant correlation with age, anaesthesia duration, pneumoperitoneum, and visual analogue scale (VAS) score 10 minutes after extubation. Multiple linear regression analysis showed 14.86% of the variance in DIA. Age (β = 0.008, P = 0.049), duration of anaesthesia (β = 0.002, P = 0.02) and VAS score 10 minutes after extubation (β = 0.128, P = 0.001) were significant independent predictors.

Conclusion

DIA decreased significantly after pelvic laparoscopic surgeries performed in the Trendelenburg position. Age, duration of anaesthesia and pain after the procedure were significant independent predictors.

Optimal positive end-expiratory pressure titration of intraoperative mechanical ventilation in different operative positions of female patients under general anesthesia

Objective

This study aimed to compare the effectiveness and safety of different titrated methods used to determine individual positive end-expiratory pressure (PEEP) for intraoperative mechanical ventilation in female patients undergoing general anesthesia in different operative positions, and provide reference ranges of optimal PEEP values based on the titration.

Methods

A total of 123 female patients who underwent elective open abdominal surgery under general anesthesia were included in this study. After endotracheal intubation, patients' body position was adjusted to the supine position, Trendelenburg positions at 10° and 20° respectively. PEEP was titrated from 20 cmH2O to 4 cmH2O, decreasing by 2 cmH2O every 1 min. Electrical impedance tomography (EIT), hemodynamic and respiratory mechanics parameters were continuously monitored and recorded. Optimal PEEP values and reference ranges were respectively calculated based on optimal EIT parameters, mean arterial pressure (MAP), and lung dynamic compliance (Cdyn).

Results

EIT-guided optimal PEEP was found to have higher values than those of the MAP-guided and Cdyn-guided methods for all three body positions (P < 0.001), and it was observed to more significantly inhibit hemodynamics (P < 0.05). The variable coefficients of EIT-guided optimal PEEP values were smaller than those of the other two methods, and this technique could provide better ventilation uniformity for dorsal/ventral lung fields and better balance for pulmonary atelectasis/collapse. The 95% reference ranges of EIT-guided optimal PEEP values were 4.6-13.8 cmH2O, 7.0-15.0 cmH2O and 8.6-17.0 cmH2O for the supine position, Trendelenburg 10°, and Trendelenburg 20° positions, respectively.

Conclusion

EIT-guided optimal PEEP titration was found to be a superior method for lung protective ventilation in different operative positions under general anesthesia. The calculated reference ranges of PEEP values based on the EIT-guided method can be used as a reference for intraoperative mechanical ventilation.

Lung mechanics during video-assisted abdominal surgery in Trendelenburg position: a cross-sectional propensity-matched comparison between classic laparoscopy and robotic-assisted surgery

BACKGROUND

Video-assisted surgery has become an increasingly used surgical technique in patients undergoing major thoracic and abdominal surgery and is associated with significant perioperative respiratory and cardiovascular changes. The aim of this study was to investigate the effect of intraoperative pneumoperitoneum during video-assisted surgery on respiratory physiology in patients undergoing robotic-assisted surgery compared to patients undergoing classic laparoscopy in Trendelenburg position.

METHODS

Twenty-five patients undergoing robotic-assisted surgery (RAS) were compared with twenty patients undergoing classic laparoscopy (LAS). Intraoperative ventilatory parameters (lung compliance and plateau airway pressure) were recorded at five specific timepoints: after induction of anesthesia, after carbon dioxide (CO₂) insufflation, one-hour, and two-hours into surgery and at the end of surgery. At the same time, arterial and end-tidal CO₂ values were noted and arterial to end-tidal CO₂ gradient was calculated.

RESULTS

We observed a statistically significant difference in plateau pressure between RAS and LAS at one-hour (26.2 ± 4.5 cmH₂O vs. 20.2 ± 3.5 cmH₂O, p = 0.05) and two-hour intervals (25.2 ± 5.7 cmH₂O vs. 17.9 ± 3.1 cmH₂O, p = 0.01) during surgery and at the end of surgery (19.9 ± 5.0 cmH₂O vs. 17.0 ± 2.7 cmH₂O, p = 0.02). Significant changes in lung compliance were also observed between groups at one-hour (28.2 ± 8.5 mL/cmH₂O vs. 40.5 ± 13.9 mL/cmH₂O, p = 0.01) and two-hour intervals (26.2 ± 7.8 mL/cmH₂O vs. 54.6 ± 16.9 mL/cmH₂O, p = 0.01) and at the end of surgery (36.3 ± 9.9 mL/cmH₂O vs. 58.2 ± 21.3 mL/cmH₂O, p = 0.01). At the end of surgery, plateau pressures remained higher than preoperative values in both groups, but lung compliance remained significantly lower than preoperative values only in patients undergoing RAS with a mean 24% change compared to 1.7% change in the LAS group (p = 0.01). We also noted a more significant arterial to end-tidal CO₂ gradient in the RAS group compared to LAS group at one-hour (12.9 ± 4.5 mmHg vs. 7.4 ± 4.4 mmHg, p = 0.02) and two-hours interval (15.2 ± 4.5 mmHg vs. 7.7 ± 4.9 mmHg, p = 0.02), as well as at the end of surgery (11.0 ± 6.6 mmHg vs. 7.0 ± 4.6 mmHg, p = 0.03).

CONCLUSION

Video-assisted surgery is associated with significant changes in lung mechanics after induction of pneumoperitoneum. The observed changes are more severe and longer-lasting in patients undergoing robotic-assisted surgery compared to classic laparoscopy.

Optimal Insertion Depth of Gastric Decompression Tube with a Thermistor for Patients Undergoing Laparoscopic Surgery in Trendelenburg Position

Monitoring core temperature is crucial for maintaining normothermia during general anesthesia. Insertion of a gastric decompression tube (GDT) may be required during laparoscopic surgery. Recently, a newly designed GDT with a thermistor for monitoring esophageal temperature has been introduced. The purpose of the present study was to evaluate the optimal insertion depth of a GDT with a thermistor. Forty-eight patients undergoing elective laparoscopic surgery in the Trendelenburg position were included in the study. The GDT was inserted to a depth of nose-earlobe-xiphoid distance (NEX) + 12 cm and withdrawn sequentially, 2 cm at a time, at 5-min intervals. Temperatures of the GDT thermistor were compared with the core temperature of the tympanic membrane (TM) using Bland and Altman analysis. The correlation between optimal insertion depth of the GDT and anatomical distance (cricoid cartilage to the carina, CCD; carina to the left hemidiaphragm, CLHD) was evaluated, and a mathematical model to predict the optimal insertion depth of the GDT with a thermistor was calculated. Temperatures of TM and GDT thermistor at NEX + 4 cm showed good agreement and strong correlation, but better agreement and stronger correlation were seen at the actual location with the most minor temperature differences. The optimal insertion depth of the GDT was estimated as -15.524 + 0.414 × CCD - 0.145 × CLHD and showed a strong correlation with the actual GDT insertion depth (correlation coefficient 0.797, adjusted R² = 0.636). The mathematical formula using CCD and CLHD would be helpful in determining the optimal insertion depth of a GDT with a thermistor.

The effect of steep head-down tilt on respiratory status in endometrial cancer patients with obesity during robot-assisted hysterectomy

•

Robot-assisted surgery with a head-down tilt of 25° or below may be safe even in patients with morbid obesity.

•

In patients with morbid obesity, a steep head-down tilt may present a risk of respiratory complications.

•

A Trendelenburg position of 20–25° is adequate to perform robot-assisted surgery for endometrial cancer.

Objective

To evaluate the effect of head-down tilt on airway pressure in gynecologic patients with obesity during robot-assisted hysterectomy.

Methods

We retrospectively reviewed the records of 27 patients with body mass index (BMI) ≥ 25 kg/m² who underwent robot-assisted hysterectomy for endometrial cancer and endometrial atypical hyperplasia using the da Vinci Xi system. Mechanical ventilation was performed using pressure-controlled ventilation (PCV). Surgery was performed at 20° (group A, n = 17) or 25° head-down tilt (group B, n = 10). Respiratory parameters, including positive end-expiratory pressure (PEEP), tidal volume (TV), mean airway pressure (P mean), and peak airway pressure (P peak), were measured before (T1) and after the head-down tilt at 1 h (T2) and 2 h (T3) during anesthesia.

Results

The median BMI was 37.5 (range 28–51) kg/m², with no between-group variation. Oxygenation was maintained intraoperatively for all patients. The expiratory carbon dioxide partial pressure was 43.6 (95% confidence interval (CI) 42.2–45.0) mmHg. The P mean peak at T2 in group B was significantly higher than in group A (P < 0.011); however, other parameters at T2 and T3 did not differ significantly between the groups. Patients with BMI ≥ 40 kg/m² had significantly higher respiratory parameters than those with BMI < 40 kg/m². In patients with BMI ≥ 40 kg/m², the mean P means and P peaks at T3 were 17.3 cmH₂O (95% CI 16.3–18.3) and 29.4 cmH₂O (95% CI 27.1–31.7), respectively.

Discussion

With careful anesthetic management during PCV, robot-assisted surgery with a head-down tilt of 25° or below may be safe, even in patients with class III obesity.

Impact of 30° Reserve Trendelenburg Position on Lung Function in Morbidly Obese Patients Undergoing Laparoscopic Sleeve Gastrectomy

Background

This study aimed to evaluate the impact of patients' positioning before and after intubation with mechanical ventilation, and after extubation on the lung function and blood oxygenation of patients with morbid obesity, who had a laparoscopic sleeve gastrectomy.

Methods

Patients with morbid obesity (BMI ≥ 30 kg/m², ASA I – II grade) who underwent laparoscopic sleeve gastrectomy at our hospital from June 2018 to January 2019 were enrolled in this prospective study. Before intubation, after intubation with mechanical ventilation, and after extubation, arterial blood was collected for blood oxygenation and gas analysis after posturing the patients at supine position or 30° reverse Trendelenburg position (30°-RTP).

Results

A total of 15 patients with morbid obesity were enrolled in this self-compared study. Pulmonary shunt (Qs/Qt) after extubation was significantly lower at 30°-RTP (18.82 ± 3.60%) compared to that at supine position (17.13 ± 3.10%, p < 0.01). Patients' static lung compliance (Cstat), during mechanical ventilation, was significantly improved at 30°-RTP (36.8 ± 6.7) compared to that of those in a supine position (33.8 ± 7.3, p < 0.05). The PaO₂ and oxygen index (OI) before and after intubation with mechanical ventilation were significantly higher at 30°-RTP compared to that at supine position, and in contrast, the P_A−aO₂ before and after intubation with mechanical ventilation was significantly reduced at 30°-RTP compared to that at supine position.

Conclusion

During and after laparoscopic sleeve gastrectomy, patients with morbid obesity had improved lung function, reduced pulmonary shunt, reduced P_A−aO₂ difference, and increased PaO₂ and oxygen index at 30°-RTP compared to that supine position.

Positive end-expiratory pressure individualization guided by continuous end-expiratory lung volume monitoring during laparoscopic surgery

To determine whether end-expiratory lung volume measured with volumetric capnography (EELV_CO2) can individualize positive end-expiratory pressure (PEEP) setting during laparoscopic surgery. We studied patients undergoing laparoscopic surgery subjected to Fowler (F-group; n = 20) or Trendelenburg (T-group; n = 20) positions. EELV_CO2 was measured at 0° supine (baseline), during capnoperitoneum (CP) at 0° supine, during CP with Fowler (head up + 20°) or Trendelenburg (head down - 30°) positions and after CP back to 0° supine. PEEP was adjusted to preserve baseline EELV_CO2 during and after CP. Baseline EELV_CO2 was statistically similar to predicted FRC in both groups. At supine and CP, EELV_CO2 decreased from baseline values in F-group [median and IQR 2079 (768) to 1545 (725) mL; p = 0.0001] and in T-group [2164 (789) to 1870 (940) mL; p = 0.0001]. Change in body position maintained EELV_CO2 unchanged in both groups. PEEP adjustments from 5.6 (1.1) to 10.0 (2.5) cmH₂O in the F-group (p = 0.0001) and from 5.6 (0.9) to 10.0 (2.6) cmH₂O in T-group (p = 0.0001) were necessary to reach baseline EELV_CO2 values. EELV_CO2 increased close to baseline with PEEP in the F-group [1984 (600) mL; p = 0.073] and in the T-group [2175 (703) mL; p = 0.167]. After capnoperitoneum and back to 0° supine, PEEP needed to maintain EELV_CO2 was similar to baseline PEEP in F-group [5.9 (1.8) cmH₂O; p = 0.179] but slightly higher in the T-group [6.5 (2.2) cmH₂O; p = 0.006]. Those new PEEP values gave EELV_CO2 similar to baseline in the F-group [2039 (980) mL; p = 0.370] and in the T-group [2150 (715) mL; p = 0.881]. Breath-by-breath noninvasive EELV_CO2 detected changes in lung volume induced by capnoperitoneum and body position and was useful to individualize the level of PEEP during laparoscopy.Trial registry: Clinicaltrials.gov NCT03693352. Protocol started 1st October 2018.

A narrative review on the potential benefits and limitations of deep neuromuscular blockade

BACKGROUND

Neuromuscular blockade was shown to improve surgical conditions. However, the risk of residual neuromuscular blockade upon extubation prevents anaesthesiologists from maintaining complete paralysis. For this reason, deep NMB is still underused in anaesthesia. This review focused on answering six questions revolving around the use of deep NMB versus moderate NMB.

METHODS

This was a non-exhaustive narrative review based on 6 selected relevant questions: does deep NMB 1) improve surgical conditions? 2) reduce surgical complications? 3) facilitate a reduction in intraoperative pneumoperitoneum pressure (PnP)? 4) does a reduction in intraoperative PnP impact clinical outcomes? 5) does the combination of deep NMB and lower PnP improve respiratory parameters? 6) improve OR efficiency or readmission rates?

RESULTS

This review highlights some of the key studies that have demonstrated potential benefits of deep NMB, but it also included reports showing no benefit, highlighting that the evidence is not unequivocal. Deep NMB does in fact improve surgical conditions, but whether this improvement translates into improved clinical outcomes is far from concluded. Indeed, there is an increased risk or residual curarisation, especially if patients are not monitored and reversed appropriately. The most important benefit of deep NMB may be the prevention of unacceptable surgical working conditions. The other potential major benefits are the reduction in PnP and reduction in pain. Deep NMB must be used with appropriate monitoring.

CONCLUSION

Deep NMB was associated with an improvement in surgical conditions, reduction in PnP, pain, and complications; but further research is needed to definitively prove this relationship.

Low-pressure versus standard pressure laparoscopic colorectal surgery (PAROS trial): a phase III randomized controlled trial

TRIAL DESIGN

This is a phase III, double-blind, randomized, controlled trial.

METHODS

In this trial, patients with laparoscopic colectomy were assigned to either low pressure (LP: 7 mmHg) or standard pressure (SP: 12 mmHg) at a ratio of 1 : 1. The aim of this trial was to assess the impact of low-pressure pneumoperitoneum during laparoscopic colectomy on postoperative recovery. The primary endpoint was the duration of hospital stay. The main secondary endpoints were postoperative pain, consumption of analgesics and postoperative morbidity.

RESULTS

Some 138 patients were enrolled, of whom 11 were excluded and 127 were analysed: 62 with LP and 65 with SP. Duration of hospital stay (3 versus 4 days; P = 0.010), visual analog scale (0.5 versus 2.0; P = 0.008) and analgesic consumption (level II: 73 versus 88 per cent; P = 0.032; level III: 10 versus 23 per cent; P = 0.042) were lower with LP. Morbidity was not significantly different between the two groups (10 versus 17 per cent; P = 0.231).

CONCLUSION

Using low-pressure pneumoperitoneum in laparoscopic colonic resection improves postoperative recovery, shortening the duration of hospitalization and decreasing postoperative pain and analgesic consumption. This suggests that low pressure should become the standard of care for laparoscopic colectomy.

TRIAL REGISTRATION

NCT03813797.

Effects of deep neuromuscular block with low-pressure pneumoperitoneum on respiratory mechanics and biotrauma in a steep Trendelenburg position

We hypothesized that deep neuromuscular blockade (NMB) with low-pressure pneumoperitoneum (PP) would improve respiratory mechanics and reduce biotrauma compared to moderate NMB with high-pressure PP in a steep Trendelenburg position. Seventy-four women undergoing robotic gynecologic surgery were randomly assigned to two equal groups. Moderate NMB group was maintained with a train of four count of 1–2 and PP at 12 mmHg. Deep NMB group was maintained with a post-tetanic count of 1–2 and PP at 8 mmHg. Inflammatory cytokines were measured at baseline, at the end of PP, and 24 h after surgery. Interleukin-6 increased significantly from baseline at the end of PP and 24 h after the surgery in moderate NMB group but not in deep NMB group (P_group*time = 0.036). The peak inspiratory, driving, and mean airway pressures were significantly higher in moderate NMB group than in deep NMB group at 15 min and 60 min after PP (P_group*time = 0.002, 0.003, and 0.048, respectively). In conclusion, deep NMB with low-pressure PP significantly suppressed the increase in interleukin-6 developed after PP, by significantly improving the respiratory mechanics compared to moderate NMB with high-pressure PP during robotic surgery.

Positive End-expiratory Pressure and Distribution of Ventilation in Pneumoperitoneum Combined with Steep Trendelenburg Position

Background

Pneumoperitoneum and a steep Trendelenburg position during robot-assisted laparoscopic prostatectomy have been demonstrated to promote a cranial shift of the diaphragm and the formation of atelectasis in the dorsal parts of the lungs. However, neither an impact of higher positive end-expiratory pressure (PEEP) on preserving the ventilation in the dorsal region nor its physiologic effects have been fully examined. The authors hypothesized that PEEP of 15 cm H2O during robot-assisted laparoscopic prostatectomy might maintain ventilation in the dorsal parts and thus improve lung mechanics.

Methods

In this randomized controlled study, 48 patients undergoing robot-assisted laparoscopic prostatectomy were included in the analysis. Patients were assigned to the conventional PEEP (5 cm H2O) group or the high PEEP (15 cm H2O) group. Regional ventilation was monitored using electrical impedance tomography before and after the establishment of pneumoperitoneum and 20° Trendelenburg position during the surgery. The primary endpoint was the regional ventilation in the dorsal parts of the lungs while the secondary endpoints were lung mechanics and postoperative lung function.

Results

Compared to that in the conventional PEEP group, the fraction of regional ventilation in the most dorsal region was significantly higher in the high PEEP group during pneumoperitoneum and Trendelenburg position (mean values at 20 min after taking Trendelenburg position: conventional PEEP, 5.5 ± 3.9%; high PEEP, 9.9 ± 4.7%; difference, –4.5%; 95% CI, –7.4 to –1.6%; P = 0.004). Concurrently, lower driving pressure (conventional PEEP, 14.9 ± 2.5 cm H2O; high PEEP, 11.5 ± 2.8 cm H2O; P &lt; 0.001), higher lung dynamic compliance, and better oxygenation were demonstrated in the high PEEP group. Postoperative lung function did not differ between the groups.

Conclusions

Application of a PEEP of 15 cm H2O resulted in more homogeneous ventilation and favorable physiologic effects during robot-assisted laparoscopic prostatectomy but did not improve postoperative lung function.

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Comparative study of the Ambu® AuraOnce™ laryngeal mask and endotracheal intubation in anesthesia airway management during neurosurgery

Objective

To investigate the feasibility and efficacy of the Ambu® AuraOnce™ laryngeal mask (LMA) compared with endotracheal intubation (ETI) during supratentorial tumor resection in the right lateral decubitus position.

Methods

This was a randomized controlled trial of LMA compared with ETI in patients who were scheduled to undergo supratentorial tumor resection in the right lateral decubitus position. The patients were randomized to the LMA (n = 40) and ETI groups (n = 40). The hemodynamic parameters (primary outcome) and mechanical ventilation parameters, anesthetic dose, and complications as well as quality of anesthesia recovery (secondary outcomes) were compared.

Results

Patients in the LMA group exhibited lower mean arterial pressure (MAP) and heart rate (HR) compared with ETI. Nine and two patients received esmolol during intubation and extubation, respectively. The airway pressure (AP) in the LMA group was higher compared with the ETI group 60 minutes after the start of surgery. Compared with the ETI group, the sufentanil dose was lower by 24% and the anesthesia recovery rate was better in the LMA group.

Conclusions

LMA can improve hemodynamic stability in patients undergoing supratentorial tumor resection in the right lateral decubitus position. If there is a clinical need and no contraindication, LMA could replace ETI.

[Cardiorespiratory effects of perioperative positioning techniques]

The supine position is still the most frequently used type of positioning during surgical procedures. Positions other than the supine position lead to physiological alterations that have a relevant influence on the course of anesthesia and surgery. As a matter of principle, hemodynamic stability is at risk because venous blood is pooled in the lower positioned body parts. In addition, head down positions (Trendelenburg position) may lead to an impairment of respiratory function by reducing lung volumes as well as lung compliance. Upright positions (beach chair position) are characterized by a relative hypovolemia accompanied by a reduction of mean arterial pressure, cardiac output and stroke volume, whereas pulmonary functions remain unchanged. Some severe adverse events have been described in the literature (e.g. intraoperative apoplexy, postoperative blindness). The pathophysiological principles and effects of hemodynamic alterations as well as potential strategies to avoid complications are presented and discussed in this lead article. Head down positions, especially the Trendelenburg position, cause a relative (intrathoracic) hypervolemia and an increase in cardiac preload that is usually well-tolerated in patients without heart problems; however, the Trendelenburg position, especially if combined with a capnoperitoneum, significantly impairs pulmonary function, can have a negative effect on intracerebral pressure and may reduce blood flow of intra-abdominal organs. The pathophysiological intraoperative changes caused by Trendelenburg positioning are described and approaches suitable for risk reduction are discussed. The prone position and lateral decubitus position have little influence on the intraoperative homeostasis. Nevertheless, there is an ongoing discussion concerning the efficacy of a 15° left lateral position during caesarean section, which is also discussed in a separate section of this review.

Exploring the intraoperative lung protective ventilation of different positive end-expiratory pressure levels during abdominal laparoscopic surgery with Trendelenburg position

Background

The intraoperative lung protective effect of mechanical ventilation of different positive end-expiratory pressure (PEEP) levels on patients undergoing abdominal laparoscopic surgery with the steep Trendelenburg position remains undefined. The purpose of the study was to explore the optimal PEEP.

Methods

Sixty patients scheduled for abdominal laparoscopic surgery were randomized to four groups including: PEEP 0, 4, 8 and 12 cmH₂O. The pulmonary dynamic compliance (Cdyn), dead space to tidal volume ratio (VD/VT), and intrapulmonary shunt ratio (QS/QT) were measured after anesthesia induction (T₀), 5 min after pneumoperitoneum (PNP) with position change (T₁), 30 (T₂) and 60 min (T₃) after PEEP, and end of surgery (T₄).

Results

Cdyn increased when different levels of PEEP (including the 4, 8, and 12 cmH₂O) were used vs. no PEEP (P<0.05). The VD/VT in PEEP 8 and 12 cmH₂O were significantly improved than no PEEP (P<0.05). Meanwhile, the QS/QT in PEEP 12 cmH₂O was higher than others during the procedures.

Conclusions

A moderate PEEP level (8 cmH₂O) with low tidal volume was sufficient to improve Cdyn and to decrease VD/VT without increasing QS/QT, which was suggested to be a good choice of intraoperative lung protective ventilation during abdominal laparoscopic surgery with Trendelenburg position.

Individualized lung recruitment maneuver guided by pulse-oximetry in anesthetized patients undergoing laparoscopy: a feasibility study

BACKGROUND

We conducted this study to test whether pulse-oximetry hemoglobin saturation (SpO₂ ) can personalize the implementation of an open-lung approach during laparoscopy. Thirty patients with SpO₂  ≥ 97% on room-air before anesthesia were studied. After anesthesia and capnoperitoneum the FIO₂ was reduced to 0.21. Those patients whose SpO₂ decreased below 97% - an indication of shunt related to atelectasis - completed the following phases: (1) First recruitment maneuver (RM), until reaching lung's opening pressure, defined as the inspiratory pressure level yielding a SpO₂ ≥ 97%; (2) decremental positive end-expiratory (PEEP) titration trial until reaching lung's closing pressure defined as the PEEP level yielding a SpO₂  < 97%; (3) second RM and, (4) ongoing ventilation with PEEP adjusted above the detected closing pressure.

RESULTS

When breathing air, in 24 of 30 patients SpO₂ was < 97%, PaO₂ /FIO₂  ˂ 53.3 kPa and negative end-expiratory transpulmonary pressure (P_TP-EE ). The mean (SD) opening pressures were found at 40 (5) and 33 (4) cmH₂ O during the first and second RM, respectively (P < 0.001; 95% CI: 3.2-7.7). The closing pressure was found at 11 (5) cmH₂ O. This SpO₂ -guided approach increased P_TP-EE (from -6.4 to 1.2 cmH₂ O, P < 0.001) and PaO₂ /FIO₂ (from 30.3 to 58.1 kPa, P < 0.001) while decreased driving pressure (from 18 to 10 cmH₂ O, P < 0.001). SpO₂ discriminated the lung's opening and closing pressures with accuracy taking the reference parameter P_TP-EE (area under the receiver-operating-curve of 0.89, 95% CI: 0.80-0.99).

CONCLUSION

The non-invasive SpO₂ monitoring can help to individualize an open-lung approach, including all involved steps, from the identification of those patients who can benefit from recruitment, the identification of opening and closing pressures to the subsequent monitoring of an open-lung condition.

The impact of obesity on pulmonary deterioration in patients undergoing robotic-assisted laparoscopic prostatectomy

Obesity affects respiratory and hemodynamic function in anesthetized patients. The aim of this study was to evaluate the influence of the body mass index (BMI) on pulmonary changes in a permanent 45° steep Trendelenburg position (STP) during robotic-assisted laparoscopic prostatectomy (RALP). 51 patients undergoing RALP under standardized anesthesia were included. Perioperative pulmonary function and oxygenation were measured in awake patients (T₀), 20 min after the induction of anesthesia (T₁), after insufflation of the abdomen in supine position (T₂), after 30 min in STP (T₃), when controlling Santorini's plexus in STP (T₄), before awakening while supine (T₅), and after 45 min in the recovery room (T₆). Patient-specific and time-dependent factor on ventilation and predicted peak inspiratory pressure (PIP), driving pressure (P_driv) and lung compliance (LC) in a linear regression model were calculated. PIP and P_driv increased significantly after induction of capnoperitoneum (T_2-4) (p < 0.0001). In univariate mixed effects models, BMI was found to be a significant predictor for PIP and P_driv increase and LC decrease. Obese patients a BMI > 31 kg/m² reached critical PIP values ≥ 35 cmH₂O. Postoperative oxygenation represented by the PaO₂/FiO₂ ratio was significantly decreased compared to T₀ (p < 0.0001). Obesity in combination with STP and capnoperitoneum during RALP has a profound effect on pulmonary function. Increased PIP and P_driv and decreased LC are directly correlated with a high BMI. Changes in PIP, P_driv and LC during RALP may be predicted in relation to patient's BMI for consideration in the preoperative setting. Trial registration number Z-2014-0387-6. Registered on 8 July 2014.

Respiratory dynamics and dead space to tidal volume ratio of volume-controlled versus pressure-controlled ventilation during prolonged gynecological laparoscopic surgery

BACKGROUND

Laparoscopic operations have become longer and more complex and applied to a broader patient population in the last decades. Prolonged gynecological laparoscopic surgeries require prolonged pneumoperitoneum and Trendelenburg position, which can influence respiratory dynamics and other measurements of pulmonary function. We investigated the differences between volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) and tried to determine the more efficient ventilation mode during prolonged pneumoperitoneum in gynecological laparoscopy.

METHODS

Twenty-six patients scheduled for laparoscopic radical hysterectomy combined with or without laparoscopic pelvic lymphadenectomy were randomly allocated to be ventilated by either VCV or PCV. Standard anesthesic management and laparoscopic procedures were performed. Measurements of respiratory and hemodynamic dynamics were obtained after induction of anesthesia, at 10, 30, 60, and 120 min after establishing pneumoperitoneum, and at 10 min after return to supine lithotomy position and removal of carbon dioxide. The logistic regression model was applied to predict the corresponding critical value of duration of pneumoperitoneum when the Ppeak was higher than 40 cmH₂O.

RESULTS

Prolonged pneumoperitoneum and Trendelenburg position produced significant and clinically relevant changes in dynamic compliance and respiratory mechanics in anesthetized patients under PCV and VCV ventilation. Patients under PCV ventilation had a similar increase of dead space/tidal volume ratio, but had a lower Ppeak increase compared with those under VCV ventilation. The critical value of duration of pneumoperitoneum was predicted to be 355 min under VCV ventilation, corresponding to the risk of Ppeak higher than 40 cmH₂O.

CONCLUSIONS

Both VCV and PCV can be safely applied to prolonged gynecological laparoscopic surgery. However, PCV may become the better choice of ventilation after ruling out of other reasons for Ppeak increasing.

Relationship Between Respiratory Dynamics and Body Mass Index in Patients Undergoing General Anesthesia with Laryngeal Mask Airway (LMA) and Comparison Between Lithotomy and Supine Positions

Background

This study aimed to compare respiratory dynamics in patients undergoing general anesthesia with a laryngeal mask airway (LMA) in lithotomy and supine positions and to validate the impact of operational position on effectiveness of LMA ventilation.

Material/Methods

A total of 90 patients (age range, 18–65 years) who underwent general anesthesia were selected and divided into supine position (SP group) and lithotomy position groups (LP group). Vital signs and respiratory dynamic parameters of the 2 groups were measured at different time points and after implantation of an LMA. The arterial blood gas was monitored at 15 min after induction. The intraoperative changes of hemodynamic indexes and postoperative adverse reactions of LMA were recorded. The possible correlation between body mass index (BMI) and respiratory dynamic indexes was analyzed.

Results

With prolonged duration of the operation, the inspiratory plateau pressure (Pplat), inspiratory resistance (RI), and work of breathing (WOB) gradually increased, while chest-lung compliance (Compl) and partial pressure of carbon dioxide in end-expiratory gas (P_etCO₂) gradually decreased (all P value <0.05). The mean airway pressure (Pmean), Pplat, and expiratory resistance (Re) in the LP group were significantly higher than in the SP group (P<0.05), while the peak inspiratory flow (FImax), peak expiratory flow (FEmax), WOB, and Compl in the LP group were significantly lower than in the SP group (P<0.05). BMI was positively correlated with peak airway pressure (PIP/Ppeak), Pplat, and airway resistance (Raw) and was negatively correlated with Compl; the differences among patients in lithotomy position were more remarkable (P<0.05).

Conclusions

The inspiratory plateau pressure and airway resistance increased with prolonged duration of the operation, accompanied by decreased chest-lung compliance. Peak airway pressure and airway resistance were positively correlated with BMI, and chest-lung compliance was negatively correlated with BMI. Changes among patients in lithotomy position were more remarkable than those in supine position.

Obesity is associated with decreased lung compliance and hypercapnia during robotic assisted surgery

Robotic assisted surgery (RAS) represents a great challenge for anesthesiology due to the increased intraabdomial pressures required for surgical optimal approach. The changes in lung physiology are difficult to predict and require fast decision making in order to prevent altered gas exchange. The aim of this study was to document the combined effect of patient physical status, medical history and intraoperative position during RAS on lung physiology and to determine perioperative risk factors for hypercapnia. We prospectively analyzed 62 patients who underwent elective RAS. Age, co-morbidities and body mass index (BMI) were recorded before surgery. Ventilatory parameters and arterial blood gas analysis were determined before induction of anesthesia, after tracheal intubation and on an hourly basis until the end of surgery. In RAS, the induction of pneumoperitoneum was associated with a significant decrease in lung compliance from a mean of 42.5–26.7 ml cm H₂O⁻¹ (p = 0.001) and an increase in plateau pressure from a mean of 16.1 mmHg to a mean of 23.6 mmHg (p = 0.001). Obesity, demonstrated by a BMI over 30, significantly correlates with a decrease in lung compliance after induction of anesthesia (p = 0.001). A significant higher increase in arterial CO₂ tension was registered in patients undergoing RAS in steep Trendelenburg position (p = 0.05), but no significant changes in end-tidal CO₂ were recorded. A higher arterial to end-tidal CO₂ tension gradient was observed in patients with a BMI > 30 (p < 0.001). In conclusion, patients’ physical status, especially obesity, represents the main risk factor for decreased lung compliance during RAS and patient positioning in either Trendelenburg or steep Trendelenburg during surgery has limited effects on respiratory physiology.

What is the evidence for the use of low-pressure pneumoperitoneum? A systematic review

Background

Laparoscopic surgery has several advantages when compared to open surgery, including faster postoperative recovery and lower pain scores. However, for laparoscopy, a pneumoperitoneum is required to create workspace between the abdominal wall and intraabdominal organs. Increased intraabdominal pressure may also have negative implications on cardiovascular, pulmonary, and intraabdominal organ functionings. To overcome these negative consequences, several trials have been performed comparing low- versus standard-pressure pneumoperitoneum.

Methods

A systematic review of all randomized controlled clinical trials and observational studies comparing low- versus standard-pressure pneumoperitoneum.

Results and conclusions

Quality assessment showed that the overall quality of evidence was moderate to low. Postoperative pain scores were reduced by the use of low-pressure pneumoperitoneum. With appropriate perioperative measures, the use of low-pressure pneumoperitoneum does not seem to have clinical advantages as compared to standard pressure on cardiac and pulmonary function. Although there are indications that low-pressure pneumoperitoneum is associated with less liver and kidney injury when compared to standard-pressure pneumoperitoneum, this does not seem to have clinical implications for healthy individuals. The influence of low-pressure pneumoperitoneum on adhesion formation, anastomosis healing, tumor metastasis, intraocular and intracerebral pressure, and thromboembolic complications remains uncertain, as no human clinical trials have been performed. The influence of pressure on surgical conditions and safety has not been established to date. In conclusion, the most important benefit of low-pressure pneumoperitoneum is lower postoperative pain scores, supported by a moderate quality of evidence. However, the quality of surgical conditions and safety of the use of low-pressure pneumoperitoneum need to be established, as are the values and preferences of physicians and patients regarding the potential benefits and risks. Therefore, the recommendation to use low-pressure pneumoperitoneum during laparoscopy is weak, and more studies are required.

Ultrasonographic comparison of two landmarks for the internal jugular vein: high versus conventional approach

OBJECTIVE

We assessed and compared two landmarks (conventional vs. high approach) used in internal jugular vein (IJV) cannulation with respect to the degree of overlap with the carotid artery (CA) and the cross-sectional area (CSA) of the IJV using ultrasonography.

PATIENTS AND METHODS

Forty-eight adult patients were included. Using ultrasonography, the percentage overlaps with the CA and the CSA of both IJVs were measured in the supine and Trendelenburg positions using conventional and high approaches. With the conventional approach, the IJV is penetrated at the apex of Sedillot's triangle, formed by the clavicle and the sternal and clavicular heads of the sternocleidomastoid muscle. The high approach involves the midpoint between the sternal notch and the mastoid process.

RESULTS

The degree of overlap with the CA was 30.5 (7.5-69.4)% [median (interquartile range)] and 0.0 (0.0-25.4)% with the conventional and high approaches, respectively, for the right IJV (P<0.001) in the Trendelenburg position with 30° head rotation. The CSA of the right IJV was 1.22 (0.92-2.01) and 0.98 (0.79-1.72) cm with the conventional and high approaches, respectively (P<0.001), in the Trendelenburg position with 30° head rotation. IJV was more deeply positioned using the high approach than the conventional approach (P<0.001).

CONCLUSION

The high approach for IJV cannulation decreased both the degree of overlap with the CA and CSA of the IJV and increased the depth of the IJV from the skin compared with the conventional approach.

Evidence for negative effects of elevated intra-abdominal pressure on pulmonary mechanics and oxidative stress

OBJECTIVE

To compare the effects of pneumoperitoneum on lung mechanics, end-tidal CO2 (ETCO2), arterial blood gases (ABG), and oxidative stress markers in blood and bronchoalveolar lavage fluid (BALF) during laparoscopic cholecystectomy (LC) by using lung-protective ventilation strategy.

MATERIALS AND METHODS

Forty-six patients undergoing LC and abdominal wall hernia (AWH) surgery were assigned into 2 groups. Measurements and blood samples were obtained before, during pneumoperitoneum, and at the end of surgery. BALF samples were obtained after anesthesia induction and at the end of surgery.

RESULTS

Peak inspiratory pressure, ETCO2, and pCO2 values at the 30th minute were significantly increased, while there was a significant decrease in dynamic lung compliance, pH, and pO2 values in LC group. In BALF samples, total oxidant status (TOS), arylesterase, paraoxonase, and malondialdehyde levels were significantly increased; the glutathione peroxidase levels were significantly decreased in LC group. The serum levels of TOS and paraoxonase were significantly higher at the end of surgery in LC group. In addition, arylesterase level in the 30th minute was increased compared to baseline. Serum paraoxonase level at the end of surgery was significantly increased when compared to AWH group.

CONCLUSIONS

Our study showed negative effects of pneumoperitoneum in both lung and systemic levels despite lung-protective ventilation strategy.

Impact of gasless laparoscopy on circulation, respiration, stress response, and other complications in gynecological geriatrics

This study aimed to explore the impact of gasless laparoscopy on circulation, respiration, stress response and other complications in gynecological surgery for old female patients. 40 patients (American Society of Anesthesiologists II-III, 60-70y) scheduled for elective gynecological laparoscopy were divided into non-pneumoperitoneum group (NP) and pneumoperitoneum group (P). All patients included were monitored for Compliance, Ppeak, Ppalt, MAP, CVP, HR, SpO2, blood gas analysis (pH, PaCO2, and PaO2), serum cortisol, TNF-α, and IL-6. There were significant differences in bowel tones recovery, postoperative shoulder pain, nausea, and vomiting between two groups (P < 0.05). In the P group, the levels of CVP, and Ppeak and Ppalt at both 10 minutes and 30 minutes after suspension/pneumoperitoneum were significantly higher than those in NP group (P < 0.05). When it came to Compliance, this trend was reversed (P < 0.05). As surgery was conducted, the plasma concentrations of cortisol, IL-6 and TNF-α in the P group were higher than those in the NP group (P < 0.05). Thus, for gynecological diseases of geriatrics, the effect on respiratory and circulatory function is less significant of gasless laparoscopy than in pneumoperitoneum. The stress response, recovery of bowl tone, should pain, nausea, and vomiting after surgery in gasless laparoscopy is improved than in pneumoperitoneum.

Ameliorating effects of CAPE on oxidative damage caused by pneumoperitoneum in rat lung tissue

We investigated the biochemical and histopathological effects of caffeic acid phenethyl ester (CAPE) against oxidative stress causing lung injury induced by pneumoperitoneum. Twenty-eight rats were selected at random and seven rats were assigned to each of the following groups. The control group (S) was subjected to a sham operation without pneumoperitoneum. The other groups were subjected to CO2 pneumoperitoneum 15 mmHg for 60 min. The laparoscopy group (L) had no additional drugs administered, the laparoscopy + alcohol (LA) group had 1 ml of 70% ethyl alcohol administered 1 h before the desufflation period, and the laparoscopy + CAPE (LC) group had CAPE administered at 10 μmol/kg 1 h before the desufflation period. The total oxidative status levels of lung and plasma were significantly increased in the LA group as compared with the LC and S group. When the LC group was compared with the L group, there was a decrease in the level of total oxidant status and increase in the levels of total antioxidant status and paraoxonase in lung tissue. The level of total antioxidative status in the S group was increased compared with the L group in lung tissue and bronchoalveolar lavage fluid. TNF-α and IL-6 were found significantly elevated in the L group compared with the LC and S groups in bronchoalveolar lavage fluid. There was a similar increase in plasma levels of IL-6. These results were supported by histopathological examination. CAPE was found to considerably reduce oxidative stress and inflammation induced by pneumoperitoneum.

Comparison of respiratory mechanics between sevoflurane and propofol-remifentanil anesthesia for laparoscopic colectomy

BACKGROUND

The creation of pneumoperitoneum and Trendelenburg positioning during laparoscopic surgery are associated with respiratory changes. We aimed to compare respiratory mechanics while using intravenous propofol and remifentanil vs. sevoflurane during laparoscopic colectomy.

METHODS

SIXTY PATIENTS UNDERGOING LAPAROSCOPIC COLECTOMY WERE RANDOMLY ALLOCATED TO ONE OF THE TWO GROUPS: group PR (propofol-remifentanil group; n = 30), and group S (sevoflurane group; n = 30). Peak inspiratory pressure (PIP), dynamic lung compliance (Cdyn), and respiratory resistance (Rrs) values at five different time points: 5 minutes after induction of anesthesia (supine position, T1), 3 minutes after pneumoperitoneum (lithotomy position, T2), 3 minutes after pneumoperitoneum while in the lithotomy-Trendelenburg position (T3), 30 minutes after pneumoperitoneum (T4), and 3 minutes after deflation of pneumoperitoneum (T5).

RESULTS

In both groups, there were significant increases in PIP and Rrs while Cdyn decreased at times T2, T3, and T4 compared to T1 (P < 0.001). The Rrs of group PR for T2, T3, and T4 were significantly higher than those measured in group S for the corresponding time points (P < 0.05).

CONCLUSIONS

Respiratory mechanics can be adversely affected during laparoscopic colectomy. Respiratory resistance was significantly higher during propofol-remifentanil anesthesia than sevoflurane anesthesia.

Anesthetic considerations in robotic-assisted gynecologic surgery

BACKGROUND

Robotic-assisted surgery has evolved over the past 2 decades with constantly improving technology that assists surgeons in multiple subspecialty disciplines. The surgical requirements of lithotomy and steep Trendelenburg positions, along with the creation of a pneumoperitoneum and lack of direct access to the patient all present management challenges in gynecologic surgery. Patient positioning requirements can have significant physiologic effects and can result in many complications.

METHODS

This review focuses on the anesthetic and surgical implications of robot-assisted technology in gynecologic surgery.

CONCLUSION

Good communication among team members and knowledge of the nuances of robotic surgery have the potential to improve patient outcomes, increase efficiency, and reduce complications.

Anesthetic Challenges in Robotic-assisted Urologic Surgery

Robotic-assisted surgery has evolved over the past two decades with constantly improving technology, assisting surgeons in multiple subspecialty disciplines. The surgical requirements of lithotomy and steep Trendelenburg positions, along with the creation of a pneumoperitoneum and limited access to the patient, all present anesthetic management challenges in urologic surgery. Patient positioning requirements can cause significant physiologic effects and may result in many complications. Good communication among team members and knowledge of the nuances of robotic surgery have the potential to improve patient outcomes, increase efficiency, and reduce surgical and anesthetic complications.

Effects of the pneumoperitoneum and Trendelenburg position on respiratory mechanics in the rats by the end-inflation occlusion method

PURPOSE:

To describe the consequences of the cranial displacement of the diaphgram occurring during pneumoperitoneum (Pnp) and/or Trendelenburg (Tnd) position on respiratory mechanics. Possible addictive effects and the changes of the viscoelastic respiratory system resistance were studied, which were not extensively described before.

METHODS:

The end-inflation occlusion method was applied on eight rats. It allows us to determine mechanical parameters such as respiratory system static elastance, the ohmic resistance due to frictional forces in the airways, and the additional viscoelastic impedance due to tissues deformation. Measurements during mechanical ventilation were taken in controls (supine position), after 20–25° head-down tilting (Tnd), after abdominal air insufflation up to 12 mmHg abdominal pressure in the supine position (Pnp), and combining Tnd + Pnp. Tnd and Pnp modalities were similar to those commonly applied during surgical procedures in humans.

RESULTS:

We confirmed the previously described detrimental effects on respiratory mechanics due to the diaphgram displacement during both Pnp and Tnd. The increment in the total resistive pressure dissipation was found to depend primarily on the effects on the viscoelastic characteristics of the respiratory system. Data suggesting greater effects of Pnp compared to those of Tnd were obtained.

CONCLUSION:

The cranial displacement of the diaphgram occurring as a consequence of Pnp and/or Tnd, for example during laparoscopic surgical procedures, causes an increment of respiratory system elastance and viscoelastic resistance. The analysis of addictive effects show that these are more likely to occur when Pnp + Tnd are compared to isolated Tnd rather than to isolated Pnp.

Arterial to end-tidal carbon dioxide pressure gradient increases with age in the steep Trendelenburg position with pneumoperitoneum

Background

Several factors affect the end-tidal carbon dioxide pressure (P_ETCO₂) and increase the arterial to end-tidal carbon dioxide pressure gradient (P_a-ETCO₂) during general anesthesia. We evaluated the relationship between age and P_a-ETCO₂ during pneumoperitoneum in the steep Trendelenburg position in patients undergoing robot-assisted laparoscopic prostatectomy (RALP).

Methods

Ninety-two consecutive patients undergoing RALP were divided by age into a middle-aged (45-65 years) and an elderly (> 65 years) group. Anesthesia was standardized. Heart rate, mean arterial pressure, peak inspiratory pressure, lung compliance, minute ventilation, P_aO₂, P_ETCO₂, P_aCO₂, and P_a-ETCO₂ were measured 10 min after intubation in the supine position without pneumoperitoneum (T0); and 10 (T1), 60 (T2), and 120 (T3) min after pneumoperitoneum in the Trendelenburg position.

Results

Although P_ETCO₂ did not change significantly during surgery, PaCO₂ and P_a-ETCO₂ increased gradually with time during pneumoperitoneum in the Trendelenburg position, and both parameters showed greater increases in the elderly than in the middle-aged group. Simple linear regression analyses revealed significant correlations between age and P_a-ETCO₂ at T0 (P = 0.018), T1 (P = 0.006), T2 (P < 0.001), and T3 (P = 0.001). Linear mixed model analysis showed that P_a-ETCO₂ was associated statistically significantly with age and duration of pneumoperitoneum in the Trendelenburg position, but age and duration of pneumoperitoneum in the Trendelenburg position were not associated (P = 0.090).

Conclusions

The magnitude of P_a-ETCO₂ during pneumoperitoneum in the steep Trendelenburg position increased with age, which could be attributed to age-related respiratory physiological changes.

Lymphangiomyomatosis discovered by massive hemoptysis during general anesthesia -A case report-

Lymphangiomyomatosis (LAM) is a rare lung disease that is characterized by the progressive proliferation of atypical smooth muscle-like cells, which leads to severe respiratory impairment and death. Dyspnea, cough, recurrent pneumothorax, and hemoptysis are the most common clinical symptoms of LAM. We report a 29-year-old female patient with massive hemoptysis during laparoscopic gynecologic surgery under general anesthesia, who was diagnosed with pulmonary LAM.