Low Pneumoperitoneum Pressure Reduces Gas Embolism During Laparoscopic Liver Resection: A Randomized Controlled Trial.

OBJECTIVE: To compare the effect of low and standard pneumoperitoneal pressure (PP) on the occurrence of gas embolism during laparoscopic liver resection (LLR). BACKGROUND: LLR has an increased risk of gas embolism. Although animal studies have shown that low PP reduces the occurrence of gas embolism, clinical evidence is lacking. METHODS: This parallel, dual-arm, double-blind, randomized controlled trial included 141 patients undergoing elective LLR. Patients were randomized into standard ("S," 15 mm Hg; n = 70) or low ("L," 10 mm Hg; n = 71) PP groups. Severe gas embolism (≥ grade 3, based on the Schmandra microbubble method) was detected using transesophageal echocardiography and recorded as the primary outcome. Intraoperative vital signs and postoperative recovery profiles were also evaluated. RESULTS: Fewer severe gas embolism cases (n = 29, 40.8% vs n = 47, 67.1%, P = 0.003), fewer abrupt decreases in end-tidal carbon dioxide partial pressure, shorter severe gas embolism duration, less peripheral oxygen saturation reduction, and fewer increases in heart rate and lactate during gas embolization episodes was found in group L than in group S. Moreover, a higher arterial partial pressure of oxygen and peripheral oxygen saturation were observed, and fewer fluids and vasoactive drugs were administered in group L than in group S. In both groups, the distensibility index of the inferior vena cava negatively correlated with central venous pressure throughout LLR, and a comparable quality of recovery was observed. CONCLUSIONS: Low PP reduced the incidence and duration of severe gas embolism and achieved steadier hemodynamics and vital signs during LLR. Therefore, a low PP strategy can be considered a valuable choice for the future LLR.

Impact of Standard Versus Low Pneumoperitoneum Pressure on Peritoneal Environment in Laparoscopic Cholecystectomy. Randomized Clinical Trial.

BACKGROUND: High CO 2 pneumoperitoneum pressure during laparoscopy adversely affects the peritoneal environment. This study hypothesized that low pneumoperitoneum pressure may be linked to less peritoneal damage and possibly to better clinical outcomes. MATERIALS AND METHODS: One hundred patients undergoing scheduled laparoscopic cholecystectomy were randomized 1:1 to low or to standard pneumoperitoneum pressure. Peritoneal biopsies were performed at baseline time and 1 hour after peritoneum insufflation in all patients. The primary outcome was peritoneal remodeling biomarkers and apoptotic index. Secondary outcomes included biomarker differences at the studied times and some clinical variables such as length of hospital stay, and quality and safety issues related to the procedure. RESULTS: Peritoneal IL6 after 1 hour of surgery was significantly higher in the standard than in the low-pressure group (4.26±1.34 vs. 3.24±1.21; P =0.001). On the contrary, levels of connective tissue growth factor and plasminogen activator inhibitor-I were higher in the low-pressure group (0.89±0.61 vs. 0.61±0.84; P =0.025, and 0.74±0.89 vs. 0.24±1.15; P =0.028, respectively). Regarding apoptotic index, similar levels were found in both groups and were 44.0±10.9 and 42.5±17.8 in low and standard pressure groups, respectively. None of the secondary outcomes showed differences between the 2 groups. CONCLUSIONS: Peritoneal inflammation after laparoscopic cholecystectomy is higher when surgery is performed under standard pressure. Adhesion formation seems to be less in this group. The majority of patients undergoing surgery under low pressure were operated under optimal workspace conditions, regardless of the surgeon's expertise.

Low-pressure pneumoperitoneum with deep neuromuscular blockade versus standard pressure pneumoperitoneum in patients undergoing laparoscopic cholecystectomy for gallstone disease: a non-inferiority randomized control trial.

BACKGROUND: Low-pressure pneumoperitoneum (LPP) is an attempt at improving laparoscopic surgery. However, it has the issue of poor working space for which deep neuromuscular blockade (NMB) may be a solution. There is a lack of literature comparing LPP with deep NMB to standard pressure pneumoperitoneum (SPP) with moderate NMB. METHODOLOGY: This was a single institutional prospective non-inferiority RCT, with permuted block randomization of subjects into group A and B [Group A: LPP; 8-10 mmHg with deep NMB [ Train of Four count (TOF): 0, Post Tetanic Count (PTC): 1-2] and Group B: SPP; 12-14 mmHg with moderate NMB]. The level of NMB was monitored with neuromuscular monitor with TOF count and PTC. Cisatracurium infusion was used for continuous deep NMB in group A. Primary outcome measures were the surgeon satisfaction score and the time for completion of the procedure. Secondarily important clinical outcomes were also reported. RESULTS: Of the 222 patients screened, 181 participants were enrolled [F: 138 (76.2%); M: 43 (23.8%); Group A n = 90, Group B n = 91]. Statistically similar surgeon satisfaction scores (26.1 ± 3.7 vs 26.4 ± 3.4; p = 0.52) and time for completion (55.2 ± 23.4 vs 52.5 ± 24.9 min; p = 0.46) were noted respectively in groups A and B. On both intention-to-treat and per-protocol analysis it was found that group A was non-inferior to group B in terms of total surgeon satisfaction score, however, non-inferiority was not proven for time for completion of surgery. Mean pain scores and incidence of shoulder pain were statistically similar up-to 7 days of follow-up in both groups. 4 (4.4%) patients in group B and 2 (2.2%) in group A had bradycardia (p = 0.4). Four (4.4%) cases of group A were converted to group B. One case of group B converted to open surgery. Bile spills and gallbladder perforations were comparable. CONCLUSION: LPP with deep NMB is non-inferior to SPP with moderate NMB in terms of surgeon satisfaction score but not in terms of time required to complete the procedure. Clinical outcomes and safety profile are similar in both groups. However, it could be marginally costlier to use LPP with deep NMB.

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 low-pressure pneumoperitoneum on pain and inflammation in laparoscopic cholecystectomy: a randomized controlled clinical trial.

OBJECTIVE: We aim to assess the effect of low-pressure pneumoperitoneum on post operative pain and ten of the known inflammatory markers. BACKGROUND: The standard of care pneumoperitoneum set pressure in laparoscopic cholecystectomy is set to 12-14 mmHg, but many societies advocate to operate at the lowest pressure allowing adequate exposure of the operative field. Many trials have described the benefits of operating at a low-pressure pneumoperitoneum in terms of lower post operative pain, and better hemodynamic stability. But only few describe the effects on inflammatory markers and cytokines. METHODS: A prospective, double-blinded, randomised, controlled clinical trial, including patients who underwent elective laparoscopic cholecystectomy. Patients randomised into low-pressure (8-10 mmHg) vs. standard-pressure (12-14 mmHg) with an allocation ratio of 1:1. Perioperative variables were collected and analysed. RESULTS: one hundred patients were allocated, 50 patients in each study arm. Low-pressure patients reported lower median pain score 6-hour post operatively (5 vs. 6, p-value = 0.021) in comparison with standard-pressure group. Eight out of 10 inflammatory markers demonstrated better results in low-pressure group in comparison with standard-pressure, but the effect was not statistically significant. Total operative time and surgery difficulty was not significantly different between the two groups even in the hands of inexperienced surgeons. CONCLUSION: low-pressure laparoscopic cholecystectomy is associated with less post operative pain and lower rise of inflammatory markers. It is feasible with comparable complications to the standard of care. Registered on ClinicalTrials.gov (NCT05530564/ September 7th, 2022).

Effect of duration of pneumoperitoneum on renal function in patients undergoing laparoscopic surgeries: a prospective observational study.

This study aimed to assess the effect of pneumoperitoneum and, thereby, raised intra-abdominal pressure for different durations (≤ 1 h, 1-3 h and > 3 h) on renal function. One hundred and twenty adult patients were allocated to four groups-the Control Group A (N = 30; patients undergoing non-laparoscopic surgery) or Group B (N = 30; patients undergoing laparoscopic surgery with duration of pneumoperitoneum < 1 h) or Group C (N = 30; patients undergoing laparoscopic surgery with duration of pneumoperitoneum 1-3 h) or Group D (N = 30; patients undergoing laparoscopic surgery with duration of pneumoperitoneum > 3 h). The baseline, intraoperative (at the end of pneumoperitoneum/surgery), and postoperative (after 6 h) values of blood urea levels, creatinine clearance, and serum cystatin C were compared. The results showed that the raised IAP (10-12 mmHg) and varying durations of pneumoperitoneum (from less than 1 h to more than 3 h) did not significantly affect renal function measured in terms of change in serum cystatin levels from baseline to 6 h in postoperative period. The varying durations of pneumoperitoneum also did not significantly affect serum creatinine or blood urea levels in the postoperative period. CTRI registration: CTRI/2016/10/007334.

Major and minor complications in Veress needle (VN) and direct trocar insertion (DTI) for laparoscopic closed-entry techniques: an updated systematic review and meta-analysis.

OBJECTIVE: Direct insertion of the trocar is an alternative method to Veress needle insertion for the creation of pneumoperitoneum. We conducted a systematic review and meta-analysis to compare these two entry closed techniques. DATA SOURCE: A systematic review of the literature was done on PubMed, MEDLINE, Embase, Scopus, and EBSCO. METHODS: The literature search was constructed until May 01, 2022, around search terms for "Veress," "direct trocar," "needle," "insertion," and "laparoscopic ways of entry." This systematic review was reported according to the PRISMA Statement 2020. RESULTS: Sixteen controlled trials (RCTs) and 5 observational studies were included in the systematic review. We found no significant differences in the risk of major complication during the access manoeuvres between DTI and VN: bowel injuries (OR = 0.76, 95% CI: 0.24-2.36, P = 0.63), major vascular injuries (OR = 1.74, 95% CI 0.56-5.38, P = 0.34), port site hernia (OR = 2.41, 95% CI: 0.28-20.71, P = 0.42). DTI has a lower risk of minor complications such as subcutaneous emphysema (OR = 5.19 95% CI: 2.27-11.87, P < 0.0001), extraperitoneal insufflation (OR = 5.93 95% CI: 1.69-20.87, P = 0.006), omental emphysema (OR = 18.41, 95% CI: 7. 01-48.34, P < 0.00001), omental bleeding (OR = 2.32, 95% CI: 1.18-4.55, P = 0.01), and lower number of unsuccessful entry or insufflation attempts (OR = 2.25, 95% CI: 1.05-4.81, P = 0.04). No significant differences were found between the two groups in terms of time required to achieve complete insufflation (MD = - 15.53, 95% CI: - 91.32 to 60.27, P = 0.69), trocar site bleeding (OR = 0.66, 95% CI, 0.25-1.79, P = 0.42), and trocar site infection (OR = 1.19, 95% CI, 0.34-4.20, P = 0.78). CONCLUSION: There were no statistically significant differences in the risk of major complications during the access manoeuvres between DTI and VN. A lower number of minor complications were observed in DTI compared with those in Veress access.

Botulinum toxin A (IncobotulinumtoxinA) and pneumoperitoneum image-guided for hernia repair with loss of dominance.

Post-incisional ventral hernia is estimated at 5-30%, when the content of the abdominal cavity migrates to the hernial sac (HSV), with a HSV/abdominal cavity volume ratio > 25%, conditioning systemic changes defined as "loss of domain". A 27-year-old male presented with ventral hernia with loss of domain that required pre-operative preparation techniques, using application of botulinum toxin A (IncobotulinumtoxinA) and pneumoperitoneum, both guided by image. A ventral plasty was performed with adequate return of the viscera to the abdominal cavity. The combination of both techniques seems to be a safe procedure to carry out a tension-free repair.

La hernia ventral postincisional se estima en 5 al 30%, cuando el contenido de la cavidad abdominal migra al saco herniario, con una relación VSH/VCA > 25% condicionando cambios sistémicos se define como "pérdida de dominio". Masculino de 27 años con hernia ventral con pérdida de dominio que ameritó técnicas de preparación preoperatoria, utilizando toxina botulínica A (IncobotulinumtoxinA) y neumoperitoneo, ambos guíados por imagen. Se realizó una plastia ventral con adecuado regreso de las vísceras a la cavidad abdominal. La combinación de ambas técnicas es un procedimiento seguro para realizar una reparación libre de tensión.

Effects of Retroperitoneal or Transperitoneal Pneumoperitoneum on Inferior Vena Cava Hemodynamics and Cardiopulmonary Function: A Prospective Real-Time Comparison.

Objective: To evaluate the effects of CO2 pneumoperitoneum on venous hemodynamics and cardiopulmonary function during transperitoneal or retroperitoneal laparoscopic surgery. Materials and Methods: A single-institution prospective study. Forty-three patients with renal-cell carcinoma undergoing retroperitoneal (22) or transperitoneal (21) laparoscopic partial nephrectomy were enrolled. Hemodynamic functions were monitored by minimally invasive FloTrac/Vigileo system. Transesophageal echocardiography was used to measure the diameter and blood flow of the inferior vena cava (IVC). Measured parameters were recorded at baseline, 10, 30, 60 minutes following insufflation to 14 mm Hg and 10 minutes following desufflation. Results: For hemodynamic changes in the transperitoneal laparoscopic surgery (TPL) and retroperitoneal laparoscopic surgery (RPL), transperitoneal CO2 insufflation resulted in a rapid parallel increase in central intravenous pressure (CVP), peak airway pressure (AWP), and IVC blood flow velocity after the first 30 minutes of pneumoperitoneum (p < 0.05). In contrast, CVP, AWP, and IVC blood flow velocity increased progressively in RPL. The variation of those parameters was significantly lower than that of TRL (p < 0.001; p = 0.002; p = 0.004). The mean maximum CVP in the two groups was 20 and 16 mm Hg, respectively. The IVC diameter at the cavoatrial junction was significantly reduced in TPL after 10 minutes of insufflation, but it remained unchanged in RPL throughout the surgery. For cardiopulmonary function changes, heart output decreased after a short period of pneumoperitoneum, but no statistical differences were observed between the two groups. The increments of partial pressure of arterial carbon dioxide and end-tidal carbon dioxide tension were significantly higher in RPL than TPL (p < 0.001; p < 0.001). Conclusions: Compared with retroperitoneal pneumoperitoneum, transperitoneal pneumoperitoneum has significant effects on IVC hemodynamics. Elevated intra-abdominal pressure (IAP) causes higher AWP and venous return resistance, which lead to the significant increase of CVP during transperitoneal approach. Adjusting the balance between IAP and CVP might be an effective way to control intravenous bleeding. Clinical Trial Registry: Registration number: ChiCTR2000038291.

Impact of pneumoperitoneum pressure during laparoscopic hysterectomy: A randomized controlled trial.

OBJECTIVE: Minimally invasive hysterectomy is a commonly performed gynecologic procedure with associated postoperative pain managed with opioid medications. Uncontrolled postoperative pain leads to increased opioid use/abuse, longer hospital stays, increase in healthcare visits, and may negatively affect patient satisfaction. Current data suggests that reduced pneumoperitoneum insufflation pressure during laparoscopic surgery may impact postoperative pain. Given the current opioid epidemic, surgeons are proactively finding ways to reduce postoperative pain. It is unclear how reduced pneumoperitoneum pressure impacts the surgeon. We investigated the impact of reduced pneumoperitoneum insufflation pressure on surgeon satisfaction. STUDY DESIGN: This was a pilot, double-blinded, randomized controlled trial from March 2020 to July 2021 comparing pneumoperitoneum pressure of 15 mmHg to reduced pressures of 12 mmHg and 10 mmHg during laparoscopic hysterectomy. RESULTS: A total of 40 patients were randomized (13 - 15 mmHg, 13 - 12 mmHg, and 14 - 10 mmHg). The primary outcome was surgeon satisfaction. Secondary outcomes included patient satisfaction, operative time, blood loss, postoperative pain, opioid usage, and discharge timing. There were no differences in baseline demographics or perioperative characteristics. Surgeon satisfaction was negatively impacted with lower pneumoperitoneum pressures greatest with 10 mmHg, including overall satisfaction (p =.01), overall effect of the pneumoperitoneum (p =.04), and quality of visualization (p =.01). There was an apparent although not statistically significant difference in operative time (p =.06) and blood loss (p =.054). There was no difference in patient satisfaction, postoperative pain scores, opioid usage, or time to discharge. CONCLUSION(S): Reduced pneumoperitoneum insufflation pressure during laparoscopic hysterectomy negatively impacted surgeon satisfaction with a trend towards longer operative times and greater blood loss, and did not positively impact patient satisfaction, postoperative pain, opioid demand, or discharge timing.

Comparison of the effect of general anesthesia and spinal anesthesia technique combined with general anesthesia on intraabdominal volume during gynecological laparoscopy.

PURPOSE: We aimed to investigate the effect of spinal anesthesia which will be performed simultaneously with general anesthesia on the site of operation with the same pressure. MATERIAL AND METHOD: This study was conducted as a randomized, prospective clinical study on 40 patients who were randomly divided into two groups. Twenty women underwent general anesthesia (Group GA) and 20 women underwent spinal anesthesia with general anesthesia (Group SGA). For all cases, preoperative height, weight, waist circumference, body mass index (kg/m2 ), the distance between both spina iliaca anterior superior, the distance of the intersection of both ribs with an imaginary line drawn over the anterior axillary line, suprapubic bone-umbilical, umbilical-xiphoid, and suprapubic bone-xiphoid distance from the midline of the abdomen were measured. Moreover, while the patient was lying in the neutral position on the operating table, the height of the highest point of the abdomen to the operating table was also measured. These measurements were repeated at intra-abdominal pressure (IAP) 14 and 25 mmHg. The amount of intra-abdominal insufflated CO2 was also recorded at IAP 14 and 25 mmHg. RESULTS: When the intra-abdominal insufflation volumes of both groups were compared at 14 and 25 mmHg, respectively, there was no statistical difference (p: 0.54, p: 0.40). When 14 and 25 mmHg were compared in all cases, a statistically significant difference was observed in other measurements except in xiphoid-umbilical distance (p < 0.05). CONCLUSION: We found that spinal anesthesia combined with GA had no effect on the abdominal volume and anthropometric measurements in laparoscopic procedures.

Impact of AirSeal® insufflation system on respiratory and circulatory dynamics during laparoscopic abdominal surgery.

The effect of the AirSeal® insufflation system on hemodynamic parameters, especially end-tidal carbon dioxide (EtCO2), during laparoscopic abdominal surgery remains unclear. This retrospective single-center study included 333 consecutive patients who underwent laparoscopic hepatectomy (n = 43), gastrectomy (n = 69), colectomy (n = 137), or proctectomy (n = 84) using the AirSeal®. Patient demographics and intraoperative hemodynamic parameters, such as EtCO2, peripheral capillary oxygen saturation (SpO2), and arterial systolic blood pressure (ABP), were collected and analyzed. EtCO2 was evaluated during the entire operative period (whole period) as well as the pneumoperitoneum period until specimen removal (pneumoperitoneum period). We defined "positive respiratory and circulatory responses" (positive responses) as a decrease in EtCO2 ≥ 3 mmHg in addition to decreases in SpO2 ≥ 3% and ABP ≥ 10 mmHg simultaneously, which suggest possible carbon dioxide (CO2) embolism. The median EtCO2 values of hepatectomy, gastrectomy, colectomy, and proctectomy in the whole period/pneumoperitoneum period were 37.3/37.4, 37.1/37.3, 37.4/37.9, and 38.2/38.4 mmHg, respectively. The EtCO2 of proctectomy was significantly higher than that of gastrectomy during the whole and pneumoperitoneum periods (P < 0.05). In contrast, the EtCO2 of hepatectomy was comparable to that of the other three surgeries in the whole and pneumoperitoneum periods. Meanwhile, nine (2.7%; eight hepatectomies and one proctectomy) patients showed positive responses, and one who underwent a partial hepatectomy developed a clinically manifested CO2 embolism. Positive responses occurred during venous exposure or bleeding in all nine cases. Although the EtCO2 of hepatectomy was comparable to that of the other surgeries using the AirSeal®, laparoscopic hepatectomy showed a tendency of CO2 embolism. Thus, a secure and careful surgical approach is mandatory for laparoscopic hepatectomy using the AirSeal® insufflation system.

A novel method for monitoring abdominal compliance to optimize insufflation pressure during laparoscopy.

BACKGROUND: Abdominal compliance describes the ease of expansion of the abdominal cavity. Several studies highlighted the importance of monitoring abdominal compliance (Cab) during the creation of laparoscopic workspace to individualize the insufflation pressure. The lack of validated clinical monitoring tools for abdominal compliance prevents accurate tailoring of insufflation pressure. Oscillometry, also known as the forced oscillation technique (FOT), is currently used to measure respiratory mechanics and has the potential to be adapted for monitoring abdominal compliance. This study aimed to define, develop and evaluate a novel approach which can monitor abdominal compliance during laparoscopy using endoscopic oscillometry. MATERIALS AND METHODS: Endoscopic oscillometry was evaluated in a porcine model for laparoscopy. A custom-built insufflator was developed for applying an oscillatory pressure signal superimposed onto a mean intra-abdominal pressure. This insufflator was used to measure the abdominal compliance at insufflation pressures ranging from 5 to 20 hPa (3.75 to 15 mmHg). The measurements were compared to the static abdominal compliance, which was measured simultaneously with computed tomography imaging. RESULTS: Endoscopic oscillometry recordings and CT images were obtained in 10 subjects, resulting in 76 measurement pairs for analysis. The measured dynamic Cab ranged between 0.0216 and 0.261 L/hPa while the static Cab based on the CT imaging ranged between 0.0318 and 0.364 L/hPa. The correlation showed a polynomial relation and the adjusted R-squared was 97.1%. CONCLUSIONS: Endoscopic oscillometry can be used to monitor changes in abdominal compliance during laparoscopic surgery, which was demonstrated in this study with a comparison with CT imaging in a porcine laparoscopy model. Use of this technology to personalize the insufflation pressure could reduce the risk of applying excessive pressure and limit the drawbacks of insufflation.

Assessment of laparoscopic working space in guinea pigs (Cavia porcellus) undergoing carbon dioxide insufflation at different intra-abdominal pressures.

OBJECTIVE: To evaluate pneumoperitoneal volumes (laparoscopic working space) in guinea pigs (Cavia porcellus) undergoing pneumoperitoneum via carbon dioxide insufflation at different intra-abdominal pressures (IAPs) (4, 6, and 8 mm Hg) and recumbencies (dorsal, right lateral, and left lateral). ANIMALS: Six 3- to 4-month-old sexually intact female Hartley guinea pigs. PROCEDURES: Guinea pigs were anesthetized, intubated, and had an abdominal insufflation catheter placed. A baseline abdominal CT scan was performed. Guinea pigs underwent insufflation, with each IAP given in a random order for 10 to 15 minutes with a washout period of 5 minutes between pressures. Abdominal CT scans were acquired at each IAP and at each recumbency. Pneumoperitoneal volumes were calculated using software. RESULTS: Increases in IAP increased working space significantly (P < .001). The 6- and 8-mm Hg pressures increased working space from 4 mm Hg by 7.3% and 19.8%, respectively. Recumbent positioning (P = .60) and body weight (P = .73) did not affect working space. Order of IAP had a significant (P = .006) effect on working space. One of the guinea pigs experienced oxygen desaturation and bradycardia at 6- and 8-mm Hg IAP. CLINICAL RELEVANCE: Although an increased working space occurred at 6 and 8 mm Hg compared to 4 mm Hg, further research is needed concerning the cardiovascular effects of pneumoperitoneum in guinea pigs to determine whether those higher IAPs are safe in this species. An IAP of 6 mm Hg can be considered for laparoscopic cannula placement, followed by a lower IAP for laparoscopic procedures.

Effect of pneumoperitoneum on gastrointestinal motility, pain behaviors, and stress biomarkers in guinea pigs (Cavia porcellus).

OBJECTIVE: To compare stress markers, gastrointestinal motility, and behavioral indicators of pain between guinea pigs undergoing pneumoperitoneum with carbon dioxide (CO2) and control guinea pigs. ANIMALS: Fourteen 4- to 5-month-old intact female Hartley guinea pigs. PROCEDURES: Guinea pigs were randomized to receive insufflation or serve as controls (anesthesia and abdominal catheter placement without insufflation), with 7 animals/group. Insufflated animals underwent 6 mm Hg of CO2 pneumoperitoneum for 30 minutes. Afterward, results for vital signs, blood glucose, fecal cortisol, appetite, fecal output, and behaviors (via video recording) were compared between the 2 groups. RESULTS: There was no difference between groups and over time for body temperature, heart rate, fecal output in grams, pellets consumed, blood glucose, and fecal cortisol. Guinea pigs that underwent insufflation had significantly more fecal pellets at 36 hours after the procedure. Several behaviors were expressed similarly between groups and over time, such as body turns, incomplete movement, rearing, lying down, drinking, and hiding. Coprophagy occurred less often in the insufflated versus noninsufflated group at 12 h postprocedure but was similar between groups at other time points. At 60 hours after the procedure, insufflated animals spent less time squinting compared to noninsufflated animals. Other behaviors were differentially expressed over time but not between treatments. CLINICAL RELEVANCE: Overall, there were no major differences in appetite, stress markers, and behaviors between insufflated and control guinea pigs. CO2 insufflation did not appear to cause undue pain or stress in guinea pigs and may be a reasonable technique to use during laparoscopy.

Quality of Recovery and Innate Immune Homeostasis in Patients Undergoing Low-pressure Versus Standard-pressure Pneumoperitoneum During Laparoscopic Colorectal Surgery (RECOVER): A Randomized Controlled Trial.

OBJECTIVE: To study the effects of intra-abdominal pressure on the quality of recovery and innate cytokine production capacity after laparoscopic colorectal surgery within the enhanced recovery after surgery program. BACKGROUND: There is increasing evidence for the safety and advantages of low-pressure pneumoperitoneum facilitated by deep neuromuscular blockade (NMB). Nonetheless, there is a weak understanding of the relationship between clinical outcomes, surgical injury, postoperative immune dysfunction, and infectious complications. METHODS: Randomized controlled trial of 178 patients treated at standard-pressure pneumoperitoneum (12 mm Hg) with moderate NMB (train-of-four 1-2) or low pressure (8 mm Hg) facilitated by deep NMB (posttetanic count 1-2). The primary outcome was the quality of recovery (Quality of Recovery 40 questionnaire) on a postoperative day 1 (POD1). The primary outcome of the immune substudy (n=100) was ex vivo tumor necrosis factor α production capacity upon endotoxin stimulation on POD1. RESULTS: Quality of Recovery 40 score on POD1 was significantly higher at 167 versus 159 [mean difference (MD): 8.3 points; 95% confidence interval (CI): 2.5, 14.1; P =0.005] and the decline in cytokine production capacity was significantly less for tumor necrosis factor α and interleukin-6 (MD: -172 pg/mL; 95% CI: -316, -27; P =0.021 and MD: -1282 pg/mL; 95% CI: -2505, -59; P =0.040, respectively) for patients operated at low pressure. Low pressure was associated with reduced surgical site hypoxia and inflammation markers and circulating damage-associated molecular patterns, with a less impaired early postoperative ex vivo cytokine production capacity. At low pressure, patients reported lower acute pain scores and developed significantly less 30-day infectious complications. CONCLUSIONS: Low intra-abdominal pressure during laparoscopic colorectal surgery is safe, improves the postoperative quality of recovery and preserves innate immune homeostasis, and forms a valuable addition to future enhanced recovery after surgery programs.

Prediction of blood pressure changes associated with abdominal pressure changes during robotic laparoscopic low abdominal surgery using deep learning.

BACKGROUND: Intraoperative hypertension and blood pressure (BP) fluctuation are known to be associated with negative patient outcomes. During robotic lower abdominal surgery, the patient's abdominal cavity is filled with CO2, and the patient's head is steeply positioned toward the floor (Trendelenburg position). Pneumoperitoneum and the Trendelenburg position together with physiological alterations during anesthesia, interfere with predicting BP changes. Recently, deep learning using recurrent neural networks (RNN) was shown to be effective in predicting intraoperative BP. A model for predicting BP rise was designed using RNN under special scenarios during robotic laparoscopic surgery and its accuracy was tested. METHODS: Databases that included adult patients (over 19 years old) undergoing low abdominal da Vinci robotic surgery (ovarian cystectomy, hysterectomy, myomectomy, prostatectomy, and salpingo-oophorectomy) at Soonchunhyang University Bucheon Hospital from October 2018 to March 2021 were used. An RNN-based model was designed using Python3 language with the PyTorch packages. The model was trained to predict whether hypertension (20% increase in the mean BP from baseline) would develop within 10 minutes after pneumoperitoneum. RESULTS: Eight distinct datasets were generated and the predictive power was compared. The macro-average F1 scores of the datasets ranged from 68.18% to 72.33%. It took only 3.472 milliseconds to obtain 39 prediction outputs. CONCLUSIONS: A prediction model using the RNN may predict BP rises during robotic laparoscopic surgery.

Benefits of AirSeal System in Laparoscopic Hysterectomy for Benign Condition: A Randomized Controlled Trial.

STUDY OBJECTIVE: To compare the AirSeal insufflation system with the standard insufflation system for postoperative abdominal pain after laparoscopic hysterectomy for benign pathology. DESIGN: Randomized controlled trial. SETTING: Teaching Hospital La Conception, Marseille, France, February 2018 to July 2020. PATIENTS: A total of 80 patients scheduled for a laparoscopic hysterectomy for benign pathology (40 per group). INTERVENTION: Laparoscopic hysterectomy using the AirSeal insufflation system with a pneumoperitoneum between 8 and 10 mm Hg compared with the standard insufflation system with a pneumoperitoneum between 12 and 15 mm Hg. MEASUREMENTS AND MAIN RESULTS: The primary end point was abdominal pain at 6 hours after the end of surgery, assessed by a Simple Numerical Scale from 0 to 10. The secondary end points were intraoperative (operating time and difficulty of the surgery felt by the operator), early postoperative (intensity of abdominal and scapular pain at H0 [end of surgery], H2 [two hours after the end of surgery, H12 [twelve hour after the end of surgery], H24 [twenty four hours after the end of surgery], H48 [fourty eight hours after the end of surgery]), and late postoperative (late postoperative complication, estimated time to return to normal life, and overall patient satisfaction assessed by the SF-12 general health survey). The median values for abdominal pain were not different between the 2 groups at 6 hours (AirSeal group median, 0; interquartile range, 2 vs standard laparoscopy group median, 1; interquartile range, 2; p = .41). The abdominal and scapular pain values were similar in both groups at all postoperative times. There were no differences between the groups regarding secondary end points. CONCLUSION: Use of the AirSeal insufflation system with low-pressure pneumoperitoneum in laparoscopic hysterectomy for a benign indication did not reduce postoperative abdominal and scapular pain.