Severe portal and systemic acidosis during CO2-laparoscopy compared to helium or gasless laparoscopy and laparotomy in a rodent model: an experimental study

Background and aims This experimental study assesses the influence of different gases and insufflation pressures on the portal, central-venous and peripheral-arterial pH during experimental laparoscopy. Methods Firstly, 36 male WAG/Rij rats were randomized into six groups (n = 6) spontaneously breathing during anaesthesia: laparoscopy using carbon dioxide or helium at 6 and 12 mmHg, gasless laparoscopy and laparotomy. 45 and 90 min after setup, blood was sampled from the portal vein, vena cava and the common femoral artery with immediate blood gas analysis. Secondly, 12 animals were mechanically ventilated at physiological arterial pH during 90 min of laparotomy (n = 6) or carbon dioxide laparoscopy at 12 mmHg (n = 6) with respective blood gas analyses. Results Over time, in spontaneously breathing rats, carbon dioxide laparoscopy caused significant insufflation pressure-dependent portal acidosis (pH at 6 mmHg, 6.99 [6.95–7.04] at 45 min and 6.95 [6.94–6.96] at 90 min, pH at 12 mmHg, 6.89 [6.82–6.90] at 45 min and 6.84 [6.81–6.87] at 90 min; p < 0.05) compared to laparotomy (portal pH 7.29 [7.23–7.30] at 45 min and 7.29 [7.20–7.30] at 90 min; p > 0.05). Central-venous and peripheral-arterial acidosis was significant but less severely reduced during carbon dioxide laparoscopy. Laparotomy, helium laparoscopy and gasless laparoscopy showed no comparable acidosis in all vessels. Portal and central-venous acidosis during carbon dioxide laparoscopy at 12 mmHg was not reversible by mechanical hyperventilation maintaining a physiological arterial pH (pH portal 6.85 [6.84–6.90] (p = 0.004), central-venous 6.93 [6.90–6.99] (p = 0.004), peripheral-arterial 7.29 [7.29–7.31] (p = 0.220) at 90 min; Wilcoxon–Mann–Whitney test). Conclusion Carbon dioxide laparoscopy led to insufflation pressure-dependent severe portal and less severe central-venous acidosis not reversible by mechanical hyperventilation.

Clinical effectiveness of gasless laparoscopic surgery for abdominal conditions: systematic review and meta-analysis

Background In high-income countries, laparoscopic surgery is the preferred approach for many abdominal conditions. Conventional laparoscopy is a complex intervention that is challenging to adopt and implement in low resource settings. This systematic review and meta-analysis evaluate the clinical effectiveness of gasless laparoscopy compared to conventional laparoscopy with CO2 pneumoperitoneum and open surgery for general surgery and gynaecological procedures. Methods A search of the MEDLINE, EMBASE, Global Health, AJOL databases and Cochrane Library was performed from inception to January 2021. All randomised (RCTs) and comparative cohort (non-RCTs) studies comparing gasless laparoscopy with open surgery or conventional laparoscopy were included. The primary outcomes were mortality, conversion rates and intraoperative complications. Secondary outcomes: operative times and length of stay. The inverse variance random-effects model was used to synthesise data. Results 63 studies were included: 41 RCTs and 22 non-RCTs (3,620 patients). No procedure-related deaths were reported in the studies. For gasless vs conventional laparoscopy there was no difference in intraoperative complications for general RR 1.04 [CI 0.45–2.40] or gynaecological surgery RR 0.66 [0.14–3.13]. In the gasless laparoscopy group, the conversion rates for gynaecological surgery were high RR 11.72 [CI 2.26–60.87] when compared to conventional laparoscopy. For gasless vs open surgery, the operative times were longer for gasless surgery in general surgery RCT group MD (mean difference) 10 [CI 0.64, 19.36], but significantly shorter in the gynaecology RCT group MD − 18.74 [CI − 29.23, − 8.26]. For gasless laparoscopy vs open surgery non-RCT, the length of stay was shorter for gasless laparoscopy in general surgery MD − 3.94 [CI − 5.93, − 1.95] and gynaecology MD − 1.75 [CI − 2.64, − 0.86]. Overall GRADE assessment for RCTs and Non-RCTs was very low. Conclusion Gasless laparoscopy has advantages for selective general and gynaecological procedures and may have a vital role to play in low resource settings.

KeyLoop: Mechanical Retraction of the Abdominal Wall for Gasless Laparoscopy

Background. Despite favorable outcomes of laparoscopic surgery in high-income countries, its implementation in low- and middle-income countries (LMICs) is challenging given a shortage of consumable supplies, high cost, and risk of power outages. To overcome these barriers, we designed a mechanical retractor that provides vertical tension on the anterior abdominal wall. Methods. The retractor design is anatomically and mathematically optimized to provide exposure similar to traditional gas-based insufflation methods. Anatomical data from computed tomography scans were used to define retractor size. The retractor is constructed of biocompatible stainless steel rods and paired with a table-mounted lifting system to provide 5 degrees of freedom. Structural integrity was assessed through finite element analysis (FEA) and load testing. Functional testing was performed in a laparotomy model. Results. A user guide based on patient height and weight was created to customize retractor size, and 4 retractor sizes were constructed. FEA data using a 13.6 kg mass (15 mm Hg pneumoperitoneum) show a maximum of 30 mm displacement with no permanent deformation. Physical load testing with applied weight from 0 to 13.6 kg shows a maximum of 60 mm displacement, again without permanent deformation. Retraction achieved a 57% larger field of view compared to an unretracted state in a laparotomy model. Conclusions. The KeyLoop retractor maintains structural integrity, is easily sterilized, and can be readily manufactured, making it a viable alternative to traditional insufflation methods. For surgeons and patients in LMICs, the KeyLoop provides a means to increase access to laparoscopic surgery.

Gasless laparoscopy versus conventional laparoscopy and laparotomy. A systematic review on the safety and efficiency

Background Gasless laparoscopy emerged to overcome the clinical and financial challenges of pneumoperitoneum and is often seen as a viable option for use in resource-limited settings as a means of saving costs and resources. This study aims to systematically review the evidence available on the safety and efficiency of gasless laparoscopy compared to conventional laparoscopy and laparotomy.Methods Following PRISMA guidelines, Medline, Embase, Web of Science and Cochrane were searched. Variables of interest were determined a priori and Covidence software was used to screen studies for inclusion without demographic preference. The quality of studies was assessed using the Cochrane Risk Assessment tool.Results Of 1080 screened studies a total of 43 studies were included. Laparoscopic cholecystectomy was by far the most studied intervention in randomized studies. In these, the mean set-up time for gasless and conventional laparoscopy was 13.14 (95% CI: -0.16–26.44) and 12.8 (95% CI: -10.86–36.47) minutes respectively; The mean duration of surgery for gasless and conventional laparoscopy was 89.39 (95% CI: 77.44-101.34) and 72.59 (95% CI: 63.44–81.74) minutes respectively and the mean length of stay was 4.25 (95% CI: 2.02–6.48) and 4.04 (95% CI: 1.72–6.36) days respectively. Most reported complications were hemorrhage and infection with no assessable statistical difference.Conclusions Although gasless laparoscopy seems to be a feasible approach for many general surgery interventions, the observed outcomes based on safety and efficiency don’t suffice to recommend gasless laparoscopy as an alternative to conventional laparoscopy or laparotomy. Larger randomized trials with a low risk of bias are warranted.