Visualising improved peritoneal perfusion at lower intra-abdominal pressure by fluorescent imaging during laparoscopic surgery: A randomised controlled study

Recovery and immune function after low pressure pneumoperitoneum during robot-assisted radical prostatectomy: a randomised controlled trial

OBJECTIVE

To compare the effectiveness of low intra-abdominal pressure (IAP) facilitated by deep neuromuscular block (NMB) to standard practice in improving the quality of recovery, preserving immune function, and enhancing parietal perfusion during robot-assisted radical prostatectomy (RARP).

PATIENTS AND METHODS

In this blinded, randomised controlled trial, 96 patients were randomised to the experimental group with low IAP (8 mmHg) facilitated by deep NMB (post-tetanic count 1-2) or the control group with standard IAP (14 mmHg) and moderate NMB (train-of-four 1-2). Recovery was measured using the 40-item Quality of Recovery questionnaire and 36-item Short-Form Health survey. Immune function was evaluated by plasma damage-associated molecular patterns, cytokines, and ex vivo lipopolysaccharide-stimulated cytokine production. Parietal peritoneum perfusion was measured by analysing the recordings of indocyanine-green injection.

RESULTS

Quality of recovery was not superior in the experimental group (n = 46) compared to the control group (n = 50). All clinical outcomes, including pain scores, postoperative nausea and vomiting, and hospital stay were similar. There were no significant differences in postoperative plasma concentrations of damage-associated molecular patterns, cytokines, and ex vivo cytokine production capacity. The use of low IAP resulted in better parietal peritoneum perfusion.

CONCLUSION

Despite better perfusion of the parietal peritoneum, low IAP facilitated by deep NMB did not improve the quality of recovery or preserve immune function compared to standard practice in patients undergoing RARP.

Moderate Intra-Abdominal Pressure Levels in Robot-Assisted Radical Prostatectomy Seem to Have No Negative Impact on Clinical Outcomes

Introduction: Radical prostatectomy is increasingly performed laparoscopically with robot assistance (RALRP). RALRP, as with all laparoscopic procedures, requires a pneumoperitoneum, which might result in peritoneal inflammatory response reactions and postoperative pain. The aim of this retrospective single-centre study was to analyse the effects of a pneumoperitoneum during RARLP on clinical outcomes. Methods: All patients who underwent robot-guided prostatectomy in our clinic were included, with the exception of patients who were converted to open prostatectomy. C-reactive protein was used as a marker for the primary outcome, namely the postoperative inflammatory response. Intra-abdominal pressure (IAP) was evaluated as a potential factor influencing inflammation. In addition, the waist-hip ratio was used to estimate the amount of visceral adipose tissue, and the administration of dexamethasone was considered as a factor influencing inflammation. The Visual Analogue Scale (VAS) was used to determine postoperative pain. Patients were consecutively recruited between 1 September 2020 and 31 March 2022. Results: A total of 135 consecutive patients were included. The median waist-hip ratio was 0.55. The median duration of the pneumoperitoneum was 143 min. The median values of the average and maximum IAP values were 10 mmHg and 15 mmHg, respectively. The mean CRP of the first postoperative day was 6.2 mg/dL. The median VAS pain level decreased from 2 to 1 from the first to the third postoperative day. On the first postoperative day, 16 patients complained of shoulder pain. In addition, 134 patients were given some form of opioid pain treatment following surgery. Conclusion: We could not identify any relevant associations between the duration and IAP of the pneumoperitoneum and the indirect markers of inflammation or indicators of pain, or between the latter and the amount of visceral adipose tissue. In addition, we found no significant effect of the administration of dexamethasone on postoperative inflammation. The results point to a noninferior tolerability of moderate pressure during the procedure compared to the commonly utilised higher pressure, yet this must be confirmed in randomised controlled trials.

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

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

Comparing different pneumoperitoneum (12 vs. 15 mmHg) pressures with cytokine analysis to evaluate clinical outcomes in patients undergoing robotic-assisted laparoscopic radical cystectomy and intracorporeal robotic urinary diversion

Background

Robotic cystectomy is the mainstay surgical intervention for treatment-refractory nonmuscle-invasive and muscle-invasive bladder cancer. However, paralytic ileus may complicate the postoperative recovery and may be a consequence of an inflammatory response associated with transient gut ischaemia. We have therefore investigated clinical, operative and inflammatory biomarker associations between paralytic ileus in the context of robotic cystectomy and intracorporeal ileal conduit urinary diversion.

Methods

Prospective consective patients referred for robotic cystectomy were consented and included in the study, while patients >75 years old and converted to open procedure were excluded. The pneumoperitoneum pressure (PP) for carbon dioxide insufflation required to perform the procedure efficiently and safely was recorded (12 or 15 mmHg). We also recorded the postoperative days patients passed flatus and stools, whether they developed ileus, as well as other standard clinical and demographic data. The expression of select proinflammatory and anti-inflammatory cytokines was determined by multiplex analysis using a cytometric bead array with changes in profiles correlated with the pressures applied and with the existence of an ileus.

Results

Twenty-seven patients were recruited, but only 20 were used in the study with 10 patients in each PP group. Seven patients were excluded all of whom had an extracorporeal ileal conduit formation. There were differences in the 40-min shorter operative time and 1 day shorter length of stay, as well as passing flatus 1 day and stools 1.5 days earlier in the 12 mmHg compared with the 15 mmHg group. More patients had ileus in the 15 mmHg group vs 12 mmHg group (30% vs. 10.0%). These were not statistically significant. Similarly, there were no statistical differences in the expression of proinflammatory cytokines at the two different pressures or between patient groups, but there were outliers, with the median indicating nonsymmetrical distribution. By comparison, anti-inflammatory cytokines showed some significant differences between groups, with IL-6 and IL-10 showing elevated levels postsurgery. No statistical difference was observed between pressures or the existence of an ileus, but the maximum levels of IL-6 and IL-10 detected in some patients reflect a pressure difference.

Conclusions

The initial findings of this novel scientific study indicated a higher risk of paralytic ileus postrobotic cystectomy and robotic intracorporeal urinary diversion when a higher pressure of 15 mmHg is used compared with 12 mmHg. Although further studies are required to establish the linkage between cytokine profile expression, pressure and ileus, our initial data reinforces the advantages of lower pressure robotic cystectomy and intracorporeal urinary diversion in patient outcomes.

An Individualized Low-Pneumoperitoneum-Pressure Strategy May Prevent a Reduction in Liver Perfusion during Colorectal Laparoscopic Surgery

High intra-abdominal pressure (IAP) during laparoscopic surgery is associated with reduced splanchnic blood flow. It is uncertain whether a low IAP prevents this reduction. We assessed the effect of an individualized low-pneumoperitoneum-pressure strategy on liver perfusion. This was a single-center substudy of the multicenter ‘Individualized Pneumoperitoneum Pressure in Colorectal Laparoscopic Surgery versus Standard Therapy II study’ (IPPCollapse–II), a randomized clinical trial in which patients received an individualized low-pneumoperitoneum strategy (IPP) or a standard pneumoperitoneum strategy (SPP). Liver perfusion was indirectly assessed by the indocyanine green plasma disappearance rate (ICG–PDR) and the secondary endpoint was ICG retention rate after 15 min (R15) using pulse spectrophotometry. Multivariable beta regression was used to assess the association between group assignment and ICG–PDR and ICG–R15. All 29 patients from the participating center were included. Median IAP was 8 (25th–75th percentile: 8–10) versus 12 (12,12) mmHg, in IPP and SPP patients, respectively (p < 0.001). ICG–PDR was higher (OR 1.42, 95%-CI 1.10–1.82; p = 0.006) and PDR–R15 was lower in IPP patients compared with SPP patients (OR 0.46, 95%-CI 0.29–0.73; p = 0.001). During laparoscopic colorectal surgery, an individualized low pneumoperitoneum may prevent a reduction in liver perfusion.

Optimization of anesthetic decision-making in ERAS using Bayesian network

Enhanced recovery after surgery (ERAS) can accelerate patient recovery. However, little research has been done on optimizing the ERAS-related measures and how the measures interact with each other. The Bayesian network (BN) is a graphical model that describes the dependencies between variables and is also a model for uncertainty reasoning. In this study, we aimed to develop a method for optimizing anesthetic decisions in ERAS and then investigate the relationship between anesthetic decisions and outcomes. First, assuming that the indicators used were independent, the effects of combinations of single indicators were analyzed based on BN. Additionally, the impact indicators for outcomes were selected with statistical tests. Then, based on the previously selected indicators, the Bayesian network was constructed using the proposed structure learning method based on Strongly Connected Components (SCC) Local Structure determination by Hill Climbing Twice (LSHCT) and adjusted according to the expert’s knowledge. Finally, the relationship is analyzed. The proposed method is validated by the real clinical data of patients with benign gynecological tumors from 3 hospitals in China. Postoperative length of stay (LOS) and total cost (TC) were chosen as the outcomes. Experimental results show that the ERAS protocol has some pivotal indicators influencing LOS and TC. Identifying the relationship between these indicators can help anesthesiologists optimize the ERAS protocol and make individualized decisions.

Low-pressure Pneumoperitoneum With Abdominal Wall Lifting Versus Standard Pressure Pneumoperitoneum in Laparoscopic Fundoplication for Gastroesophageal Reflux Disease: A Propensity Score-matched Analysis

OBJECTIVE

The objective of this study was to compare the treatment results of low-pressure pneumoperitoneum with abdominal wall lifting (AWL+LP, 6 mm Hg) versus standard pressure pneumoperitoneum (SP, 12 mm Hg) during laparoscopic fundoplication for gastroesophageal reflux disease (GERD), using propensity score matching (PSM).

MATERIALS AND METHODS

A retrospective analysis was made of 362 patients, 123 in the AWL+LP group and 239 in the SP group, who underwent laparoscopic fundoplication for GERD from January 2010 to December 2017. Perioperative and prognostic outcomes were compared after PSM with 1:1 match.

RESULTS

After PSM, 107 matched pairs were obtained. Compared with the SP group at 30 and 60 minutes after pneumoperitoneal initiation, the AWL+LP group showed significantly lower end-tidal carbon dioxide value (P<0.001, <0.001, respectively), lower partial pressure of carbon dioxide value (P<0.001, 0.016, respectively) and significantly higher pH value (P<0.001, <0.001, respectively). However, postoperative shoulder pain, abdominal pain, and arrhythmia in the AWL+LP group were less than those in SP group (P=0.01, 0.017, 0.005, respectively). There was no significant difference in operative time (106.54±27.80 vs. 107.38±24.78 min), blood loss [15 mL (interquartile range: 12.5 to 20 mL) vs.15 mL (interquartile range: 10 to 20 mL)], length of stay (4 vs. 4 d), the wound ecchymosis [2 (1.87%) vs. 3 (2.80%)] and rates of recurrence [8 (7.48%) vs. 5 (4.67%)] between AWL+LP group and SP group.

CONCLUSION

AWL+LP resulted in comparable perioperative and prognostic outcomes with less impact on changes in cardiorespiratory function compared with SP approaches of laparoscopic fundoplication for GERD.

The "Dark Side" of Pneumoperitoneum and Laparoscopy

Laparoscopic surgery has been one of the most common procedures for abdominal surgery at pediatric age during the last few decades as it has several advantages compared to laparotomy, such as shorter hospital stays, less pain, and better cosmetic results. However, it is associated with both local and systemic modifications. Recent evidence demonstrated that carbon dioxide pneumoperitoneum might be modulated in terms of pressure, duration, temperature, and humidity to mitigate and modulate these changes. The aim of this study is to review the current knowledge about animal and human models investigating pneumoperitoneum-related biological and histological impairment. In particular, pneumoperitoneum is associated with local and systemic inflammation, acidosis, oxidative stress, mesothelium lining abnormalities, and adhesion development. Animal studies reported that an increase in pressure and time and a decrease in humidity and temperature might enhance the rate of comorbidities. However, to date, few studies were conducted on humans; therefore, this research field should be further investigated to confirm in experimental models and humans how to improve laparoscopic procedures in the spirit of minimally invasive surgeries.

Real-time fluorescence imaging in intraoperative decision making for cancer surgery

Fluorescence-guided surgery is an intraoperative optical imaging method that provides surgeons with real-time guidance for the delineation of tumours. Currently, in phase 1 and 2 clinical trials, evaluation of fluorescence-guided surgery is primarily focused on its diagnostic performance, although the corresponding outcome variables do not inform about the added clinical benefit of fluorescence-guided surgery and are challenging to assess objectively. Nonetheless, the effect of fluorescence-guided surgery on intraoperative decision making is the most objective outcome measurement to assess the clinical value of this imaging method. In this Review, we explore the study designs of existing trials of fluorescence-guided surgery that allow us to extract information on potential changes in intraoperative decision making, such as additional or more conservative resections. On the basis of this analysis, we offer recommendations on how to report changes in intraoperative decision making that result from fluorescence imaging, which is of utmost importance for the widespread clinical implementation of fluorescence-guided surgery.

Modeling intra-abdominal volume and respiratory driving pressure during pneumoperitoneum insufflation-a patient-level data meta-analysis

During pneumoperitoneum, intra-abdominal pressure (IAP) is usually kept at 12-14 mmHg. There is no clinical benefit in IAP increments if they do not increase intra-abdominal volume IAV. We aimed to estimate IAV (ΔIAV) and respiratory driving pressure changes (ΔP_RS) in relation to changes in IAP (ΔIAP). We carried out a patient-level meta-analysis of 204 adult patients with available data on IAV and ΔP_RS during pneumoperitoneum from three trials assessing the effect of IAP on postoperative recovery and airway pressure during laparoscopic surgery under general anesthesia. The primary endpoint was ΔIAV, and the secondary endpoint was ΔP_RS. The endpoints' response to ΔIAP was modeled using mixed multivariable Bayesian regression to estimate which mathematical function best fitted it. IAP values on the pressure-volume (PV) curve where the endpoint rate of change according to IAP decreased were identified. Abdomino-thoracic transmission (ATT) rate, that is, the rate ΔP_RS change to ΔIAP was also estimated. The best-fitting function was sigmoid logistic and linear for IAV and ΔP_RS response, respectively. Increments in IAV reached a plateau at 6.0 [95%CI 5.9-6.2] L. ΔIAV for each ΔIAP decreased at IAP ranging from 9.8 [95%CI 9.7-9.9] to 12.2 [12.0-12.3] mmHg. ATT rate was 0.65 [95%CI 0.62-0.68]. One mmHg of IAP raised ΔP_RS 0.88 cmH₂O. During pneumoperitoneum, IAP has a nonlinear relationship with IAV and a linear one with ΔP_RS. IAP should be set below the point where IAV gains diminish.NEW & NOTEWORTHY We found that intra-abdominal volume changes related to intra-abdominal pressure increase reached a plateau with diminishing gains in commonly used pneumoperitoneum pressure ranges. We also found a linear relationship between intra-abdominal pressure and respiratory driving pressure, a known marker of postoperative pulmonary complications.