Low Intra-abdominal Pressure Research Articles

Spinal Anesthesia for Laparoscopic Cholecystectomy in Parkinson’s disease

Parkinson's disease, a neurodegenerative disorder, presents with resting tremor, muscle rigidity and bradykinesia. Affecting multiple organ-systems, it's an important cause of peri-operative morbidity. General anaesthesia may deteriorate cardio-pulmonary and neuro-cognitive functions; moreover, medications used may interact with anti-parkinsonian agents. Spinal anaesthesia is usually avoided in Parkinson's disease. However, it offers neurologic monitoring and less surgical stress response and avoids complications of general anaesthesia. This case report aims to demonstrate application of spinal anaesthesia for laparoscopic cholecystectomy in a Parkinson's elderly with pulmonary dysfunction and anticipated difficult airway management. Sensory blockade of third thoracic dermatome was achieved. Bupivacaine was instilled intra-peritoneally. Surgery was smooth at low intra-abdominal pressure. Regular Paracetamol provided satisfactory post-operative analgesia. Single episode of post-operative vomiting was effectively managed. Without deterioration, patient was discharged from hospital on third day. Spinal anaesthesia is a valid technique for laparoscopic cholecystectomy in needy patients with multiple peri-operative risks. Keywords: Laparoscopic cholecystectomy; Parkinson's disease; spinal anaesthesia.

A multifaceted individualized pneumoperitoneum strategy for laparoscopic colorectal surgery: a multicenter observational feasibility study.

While guidelines for laparoscopic abdominal surgery advise using the lowest possible intra-abdominal pressure, commonly a standard pressure is used. We evaluated the feasibility of a predefined multifaceted individualized pneumoperitoneum strategy aiming at the lowest possible intra-abdominal pressure during laparoscopic colorectal surgery. Multicenter prospective study in patients scheduled for laparoscopic colorectal surgery. The strategy consisted of ventilation with low tidal volume, a modified lithotomy position, deep neuromuscular blockade, pre-stretching of the abdominal wall, and individualized intra-abdominal pressure titration; the effect was blindly evaluated by the surgeon. The primary endpoint was the proportion of surgical procedures completed at each individualized intra-abdominal pressure level. Secondary endpoints were the respiratory system driving pressure, and the estimated volume of insufflated CO2 gas needed to perform the surgical procedure. Ninety-two patients were enrolled in the study. Fourteen cases were converted to open surgery for reasons not related to the strategy. The intervention was feasible in all patients and well-accepted by all surgeons. In 61 out of 78 patients (78%), surgery was performed and completed at the lowest possible IAP, 8mmHg. In 17 patients, IAP was raised up to 12mmHg. The relationship between IAP and driving pressure was almost linear. The mean estimated intra-abdominal CO2 volume at which surgery was performed was 3.2L. A multifaceted individualized pneumoperitoneum strategy during laparoscopic colorectal surgery was feasible and resulted in an adequate working space in most patients at lower intra-abdominal pressure and lower respiratory driving pressure. ClinicalTrials.gov (Trial Identifier: NCT03000465).

Lower intra-abdominal pressure has no cardiopulmonary benefits during laparoscopic colorectal surgery: a double-blind, randomized controlled trial.

Higher intra-abdominal pressure may impair cardiopulmonary functions during laparoscopic surgery. While 12-15mmHg is generally recommended as a standard pressure, the benefits of lower intra-abdominal pressure are unclear. We thus studied whether the low intra-abdominal pressure compared with the standard pressure improves cardiopulmonary dynamics during laparoscopic surgery. Patients were randomized according to the intra-abdominal pressure and neuromuscular blocking levels during laparoscopic colorectal surgery: low pressure (8mmHg) with deep-block (post-tetanic count 1-2), standard pressure (12mmHg) with deep-block, and standard pressure with moderate-block (train-of-four count 1-2) groups. During the laparoscopic procedure, we recorded cardiopulmonary variables including cardiac index, pulmonary compliance, and surgical conditions. We also assessed postoperative pain intensity and recovery time of bowel movement. The primary outcome was the cardiac index 30min after onset of laparoscopy. Patients were included in the low pressure with deep-block (n = 44), standard pressure with deep-block (n = 44), and standard pressure with moderate-block (n = 43) groups. The mean (SD) of cardiac index 30min after laparoscopy was 2.7 (0.7), 2.7 (0.9), and 2.6 (1.0) Lmin-1m-2 in each group (P = 0.715). The pulmonary compliance was higher but the surgical condition was poorer in the low intra-abdominal pressure than the standard pressure (both P < 0.001). Other variables were comparable between groups. We observed few cardiopulmonary benefits but poor surgical conditions in the low intra-abdominal pressure during laparoscopy. Considering cardiopulmonary dynamics and surgical conditions, the standard intra-abdominal pressure may be preferable to the low pressure for laparoscopic surgery.

Deep neuromuscular blockade : Benefits and risks

Neuromuscular blockade (TOF count = 0) can improve tracheal intubation and microlaryngeal surgery. It is also frequently used in many surgical fields including both nonlaparoscopic and laparoscopic surgery to improve surgical conditions and to prevent sudden muscle contractions. Currently there is acontroversy regarding the need and the clinical benefits of deep neuromuscular blockade for different surgical procedures. Deep neuromuscular relaxation improves laparoscopic surgical space conditions only marginally when using low intra-abdominal pressure. There is no outcome-relevant advantage of low compared to higher intra-abdominal pressures, but worsen the surgical conditions. Postoperative, residual curarisation can be avoided by algorithm-based pharmacological reversing and quantitative neuromuscular monitoring.

Prevention and Management of Complications in Laparoscopic Myomectomy.

Myomectomy aims to preserve fertility, treat abnormal uterine bleeding, and alleviate pain. It should cause minimal damage to the endometrium, while being tolerable and durable, and reduce the incidence of myoma recurrence and complications including bleeding, hematoma, adhesions, and gravid uterus perforation. Training and experience are crucial to reduce complications. The surgical strategy depends on imaging information on the myomas. The position of the optical and secondary ports will determine the degree of ergonomic surgery performance, time and difficulty of myoma enucleation, and the suturing quality. Appropriate hysterotomy length relative to myoma size can decrease bleeding, coagulation, and suturing times. Bipolar coagulation of large vessels, while avoiding carbonization and myometrium gaps after suturing, may decrease the risk of myometrial hematoma. Quality surgery and the use of antiadhesive barriers may reduce the risk of postoperative adhesions. Slow rotation of the beveled morcellator and good control of the bag could reduce de novo myoma and endometriosis. Low intra-abdominal CO2 pressure may reduce the risk of benign and malignant cell dissemination. The benefits a patient gains from laparoscopic myomectomy are greater than the complication risks of laparoscopic morcellation. Recent publications on laparoscopic myomectomies demonstrate reduced hospitalization stays, postoperative pain, blood loss, and recovery compared to open surgery.

Core Body Temperature but Not Intraabdominal Pressure Predicts Postoperative Complications Following Closed-System Hyperthermic Intraperitoneal Chemotherapy (HIPEC) Administration.

Hyperthermic intraperitoneal chemotherapy (HIPEC) following cytoreductive surgery (CRS), performed using closed-abdomen technique (CAT), may affect intraabdominal pressure (IAP). High IAP may increase postoperative complications due to decreased venous return and hypoperfusion to vital organs. Elevated core body temperature (CBT) may cause multiorgan dysfunction. Low IAP or CBT could result in suboptimal HIPEC and potentially translate into early disease recurrence. The aim of the present study is to identify possible correlations between IAP or CBT and postoperative complications. Continuous intraabdominal pressure measurement was performed by intraabdominal catheter. Inflow temperature was set at 44°C, and mean perfusate temperature was 42°C. CBT was measured continuously in the distal esophagus. We compared the rate of postoperative complications between the low IAP group (2-10mmHg, n=28), target IAP group (10-20mmHg, n=71), and high IAP group (20-34mmHg, n=16) as well as with CBT as a continuous variable. 115 patients were included in the study. There was no difference between IAP groups in terms of age, gender, primary diagnosis, operative peritoneal cancer index, CBT, or operative time. There was no correlation between IAP and postoperative complications or with prolonged hospital stay. On multivariate analysis, elevated mean CBT was a positive predictor of postoperative complications (p=0.035). IAP level during closed-abdomen technique HIPEC is not associated with postoperative complications. However, elevated CBT may increase postoperative complications.

Erratum to: Quality of Recovery After Low-Pressure Laparoscopic Donor Nephrectomy Facilitated by Deep Neuromuscular Blockade: A Randomized Controlled Study.

The use of low intra-abdominal pressure (<10 mmHg) reduces postoperative pain scores after laparoscopic surgery. To investigate whether low-pressure pneumoperitoneum with deep neuromuscular blockade improves the quality of recovery after laparoscopic donor nephrectomy (LDN). In a single-center randomized controlled trial, 64 live kidney donors were randomly assigned to 6 or 12 mmHg insufflation pressure. A deep neuromuscular block was used in both groups. Surgical conditions were rated by the five-point Leiden-surgical rating scale (L-SRS), ranging from 5 (optimal) to 1 (extremely poor) conditions. If the L-SRS was insufficient, the pressure was increased stepwise. The primary outcome measure was the overall score on the quality of recovery-40 (QOR-40) questionnaire at postoperative day 1. The difference in the QOR-40 scores on day 1 between the low- and standard-pressure group was not significant (p = .06). Also the overall pain scores and analgesic consumption did not differ. Eight procedures (24%), initially started with low pressure, were converted to a standard pressure (≥10 mmHg). A L-SRS score of 5 was significantly more prevalent in the standard pressure as compared to the low-pressure group at 30 min after insufflation (p < .01). Low-pressure pneumoperitoneum facilitated by deep neuromuscular blockade during LDN does not reduce postoperative pain scores nor improve the quality of recovery in the early postoperative phase. The question whether the use of deep neuromuscular blockade during laparoscopic surgery reduces postoperative pain scores independent of the intra-abdominal pressure should be pursued in future studies. The trial was registered at clinicaltrial.gov before the start of the trial (NCT02146417).

Quality of Recovery After Low-Pressure Laparoscopic Donor Nephrectomy Facilitated by Deep Neuromuscular Blockade: A Randomized Controlled Study

BackgroundThe use of low intra-abdominal pressure (<10 mmHg) reduces postoperative pain scores after laparoscopic surgery.ObjectiveTo investigate whether low-pressure pneumoperitoneum with deep neuromuscular blockade improves the quality of recovery after laparoscopic donor nephrectomy (LDN).Design, setting and participantsIn a single-center randomized controlled trial, 64 live kidney donors were randomly assigned to 6 or 12 mmHg insufflation pressure. A deep neuromuscular block was used in both groups. Surgical conditions were rated by the five-point Leiden-surgical rating scale (L-SRS), ranging from 5 (optimal) to 1 (extremely poor) conditions. If the L-SRS was insufficient, the pressure was increased stepwise.Main outcome measureThe primary outcome measure was the overall score on the quality of recovery-40 (QOR-40) questionnaire at postoperative day 1.ResultsThe difference in the QOR-40 scores on day 1 between the low- and standard-pressure group was not significant (p = .06). Also the overall pain scores and analgesic consumption did not differ. Eight procedures (24%), initially started with low pressure, were converted to a standard pressure (≥10 mmHg). A L-SRS score of 5 was significantly more prevalent in the standard pressure as compared to the low-pressure group at 30 min after insufflation (p < .01).ConclusionsLow-pressure pneumoperitoneum facilitated by deep neuromuscular blockade during LDN does not reduce postoperative pain scores nor improve the quality of recovery in the early postoperative phase. The question whether the use of deep neuromuscular blockade during laparoscopic surgery reduces postoperative pain scores independent of the intra-abdominal pressure should be pursued in future studies.Trial registrationThe trial was registered at clinicaltrial.gov before the start of the trial (NCT02146417).

Next Step in Cost Containment of Public Hospital Economy Could Be Merging of Anesthesia and Surgery Budgets.

Next Step in Cost Containment of Public Hospital Economy Could Be Merging of Anesthesia and Surgery Budgets.

Intraabdominal Pressure and Postoperative Discomfort in Laparoscopic Roux-en-Y Gastric Bypass (RYGB) Surgery: a Randomized Study.

High intraabdominal pressure (IAP) during laparoscopic surgery has been associated with postoperative discomfort. Effects on nausea and access have not been subjected to randomized studies. In cholecystectomy, lower IAP may cause less pain, but nausea and surgical access in RYGB surgery have not been investigated. We studied the influence of two IAP levels on surgical access, operation time, postoperative pain, and nausea. Fifty consecutive female gastric bypass patients were randomized to intraabdominal pressure of 12 (IAP12) or 18 (IAP18) mm Hg. Surgeons and personnel were blinded to randomization; study groups were well matched for age and BMI. Operative time was noted in minutes. Visual analogue scales were used for assessing access and for patients assessing pain (abdomen-shoulder) and nausea (supine-standing) at six time points during the first 16 postoperative hours. Rescue medication was recorded. In 3/25 patients in the IAP12 group, the code was broken due to access problems vs. 0/25 in the IAP18 group (p = 0.1398). Operative time did not differ. Access was significantly better for IAP18 (92.2 ± 2.3 vs. 69.3 ± 4.2; p = 0.0001). Postoperative shoulder pain was maximal after 6h but throughout less than in the abdomen (p < 0.0001); there were no differences in pain between IAP18 and IAP12 (p = 0.7408). Postoperative nausea was significantly greater standing than supine but without differences between groups. Higher IAP gives better surgical access in laparoscopic Roux-en-Y gastric bypass with no negative effect on pain or nausea.

Increased pressure within the abdominal compartment: intra-abdominal hypertension and the abdominal compartment syndrome.

This article reviews recent developments related to intra-abdominal hypertension (IAH)/abdominal compartment syndrome (ACS) and clinical practice guidelines published in 2013. IAH/ACS often develops because of the acute intestinal distress syndrome. Although the incidence of postinjury ACS is decreasing, IAH remains common and associated with significant morbidity and mortality among critically ill/injured patients. Many risk factors for IAH include those findings suggested to be indications for use of damage control surgery in trauma patients. Medical management strategies for IAH/ACS include sedation/analgesia, neuromuscular blocking and prokinetic agents, enteral decompression tubes, interventions that decrease fluid balance, and percutaneous catheter drainage. IAH/ACS may be prevented in patients undergoing laparotomy by leaving the abdomen open where appropriate. If ACS cannot be prevented with medical or surgical management strategies or treated with percutaneous catheter drainage, guidelines recommend urgent decompressive laparotomy. Use of negative pressure peritoneal therapy for temporary closure of the open abdomen may improve the systemic inflammatory response and patient-important outcomes. In the last 15 years, investigators have better clarified the pathogenesis, epidemiology, diagnosis, and appropriate prevention of IAH/ACS. Subsequent study should be aimed at understanding which treatments effectively lower intra-abdominal pressure and whether these treatments ultimately affect patient-important outcomes.

Laparoscopic cholecystectomy perioperative management: an update

Laparoscopic cholecystectomy is one of the most common general surgical procedures. The aim of the present paper is to review current evidence and well-established practice for elective laparoscopic perioperative management. There is no firm evidence for best anesthetic technique, further high quality studies assessing short as well as more protracted outcomes are needed. Preventive multi-modal analgesia, combining non-opioid analgesics, paracetamol, nonsteroidal anti-inflammatory drugs or coxib, and local anesthesia, has a long history. Local anesthesia improves postoperative pain and facilitates discharge on the day of surgery. Whether transversus abdominis plane-block has clinically important advantages compared to local infiltration analgesia needs further studies. Single intravenous dose steroid, dexamethasone, reduces postoperative nausea and vomiting, pain, and enhances the recovery process. Multi-modal analgesia is reassuringly safe thus having a positive benefit versus risk profile. Adherence to modern guidelines avoiding prolonged fasting and liberal intravenous fluid regime supports rapid recovery. The effects of CO 2 insufflation must be acknowledged and low intra-abdominal pressure should be sought in order to reduce negative cardiovascular/respiratory effects. There is no firm evidence supporting heating and humidification of the insufflated gas. The potential risk for CO 2 /gas entrainment into vasaculture, gas emboli, or subcutaneous/intra-thoracic into the pleural space must be kept in mind. Laparoscopic cholecystectomy in ASA 1-2 patients following a multi-modal enhanced recovery protocol promotes high success rate for discharge on the day of surgery.

Deep neuromuscular block reduces intra-abdominal pressure requirements during laparoscopic cholecystectomy: a prospective observational study.

Laparoscopic surgery causes specific post-operative discomfort and intraoperative cardiovascular, pulmonary, and splanchnic changes. The CO2 pneumoperitoneum-related intra-abdominal pressure (IAP) remains one of the main drivers of these changes. We investigated the influence of deep neuromuscular blockade (NMB) on IAP and surgical conditions. This is an open prospective single-subject design study in 20 patients (14 female/6 male) undergoing laparoscopic cholecystectomy. Inclusion criteria were 18 years or older, and American Society of Anesthesiologists classification 1 to 3. Under a standardised anaesthesia, lowest IAP providing adequate surgical conditions was assessed without NMB and with deep NMB [post-tetanic count (PTC)<2] with rocuronium. The differences between IAP allowing for an adequate surgical field before and after administration of rocuronium were determined, as were effects of patient gender, age, and body mass index. Mean IAP without NMB was 12.75 (standard deviation 4.49) mmHg. Immediately after achieving a deep NMB, this was 7.20 (2.51). This pressure difference of 5.55 mmHg (5.08, P<0.001) dropped to 3.00 mmHg (4.30, P<0.01) after 15 min. Higher IAP differences were found in women compared with men. A modest inverse relationship was found between pressure difference and age. We found an almost 25% lower IAP after a deep NMB compared with no block in laparoscopic cholecystectomy. Younger and female patients appear to benefit more from deep neuromuscular blockade to reduce IAP.

Urinary biomarkers after donor nephrectomy.

As the beginning of living-donor kidney transplantation, physicians have expressed concern about the possibility that unilateral nephrectomy can be harmful to a healthy individual. To investigate whether the elevated intra-abdominal pressure (IAP) during laparoscopic donor nephrectomy causes early damage to the remaining kidney, we evaluated urine biomarkers after laparoscopic donor nephrectomy. We measured albumin and alpha-1-microglobulin (α-1-MGB) in urine samples collected during and after open and laparoscopic donor nephrectomy and laparoscopic cholecystectomy and colectomy. Additionally, kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) were measured in urine samples collected during and after laparoscopic donor nephrectomy and colectomy. The same biomarkers were studied in patients randomly assigned to standard or low IAP during laparoscopic donor nephrectomy. We observed a peak in urinary albumin excretion during all procedures. Urine α-1-MGB rose in the postoperative period with a peak on the third postoperative day after donor nephrectomy. Urine α-1-MGB did not increase after laparoscopic cholecystectomy and colectomy. After laparoscopic nephrectomy, we observed slight increases in urine KIM-1 during surgery and in urine NGAL at day 2-3 after the procedure. After laparoscopic colectomy, both KIM-1 and NGAL were increased in the postoperative period. There were no differences between the high- and low-pressure procedure. Elevated urinary α-1-MGB suggests kidney damage after donor nephrectomy, occurring irrespective of IAP during the laparoscopic procedure.

Laparoskopija sa niskim intrabadominalnim pritiskom i bezplinska laparoskopija u abdominalnoj hirurgiji

Knowledge of pathophysiological basis of laparoscopic procedures, that is, the influence of CO2 pneumoperitoneum (PNP) on the body in particular, can prevent the complications during laparoscopy to occur. Standard intra-abdominal pressure (IAP), which is used during laparoscopic surgery, is 12-15 mm / Hg. The direct effect of CO2 pneumoperitoneum is a result of mechanical action of the gas and incensement of intra-abdominal pressure (IAP). The indirect effect of CO2 pneumoperitoneum is caused by the absorption of gas inserted into the abdomen. Analysis of published articles that assess the effects of CO2 pneumoperitoneum on the body and abdominal organs contributes to a better usage of the laparoscopic method. Different techniques in laparoscopy, created as an alternative to standard CO2-pneumoperitoneum, have the task to reduce the risks for patients with comorbidity and simultaneously raise the abdominal wall and allow the surgeon to perform smooth operation, which is especially important for ASA III and ASA IV patients. Alternative techniques can be divided into three groups: laparoscopy using pneumoperitoneum with low intra-abdominal pressure (up to 8 mm / Hg), laparoscopy using retractors abdominal wall and limited pneumoperitoneum, and laparoscopy without the use of gas (gasless laparoscopy; raising the abdominal wall retractor only ). Low insufflation pressure in the abdomen (up to 8 mm / Hg) is beneficial for patients with laparoscopic procedures and its routine usage in elderly patients and patients with severe cardiorespiratory diseases, should be common practice. Gasless laparoscopy was created because of the need to prevent the negative effects of increased intra-abdominal pressure on the body during laparoscopy, primarily in patients with high comorbidity (ASA III and ASA IV). When compared to other techniques, numerous studies prefer laparoscopy with low insufflation pressure, but in practice this is not done routinely, yet each technique is applied selectively, according to the needs and condition of the patient, which is the most appropriate. To avoid the side effects of CO2 pneumoperitoneum, which is important in high-risk patients, it is more likely to operate on low IAP (6-8 mm / Hg) or use gasless laparoscopy. This is especially important for long - duration operations.

Pressure Measurement Techniques for Abdominal Hypertension: Conclusions from an Experimental Model.

Introduction. Intra-abdominal pressure (IAP) measurement is an indispensable tool for the diagnosis of abdominal hypertension. Different techniques have been described in the literature and applied in the clinical setting. Methods. A porcine model was created to simulate an abdominal compartment syndrome ranging from baseline IAP to 30 mmHg. Three different measurement techniques were applied, comprising telemetric piezoresistive probes at two different sites (epigastric and pelvic) for direct pressure measurement and intragastric and intravesical probes for indirect measurement. Results. The mean difference between the invasive IAP measurements using telemetric pressure probes and the IVP measurements was −0.58 mmHg. The bias between the invasive IAP measurements and the IGP measurements was 3.8 mmHg. Compared to the realistic results of the intraperitoneal and intravesical measurements, the intragastric data showed a strong tendency towards decreased values. The hydrostatic character of the IAP was eliminated at high-pressure levels. Conclusion. We conclude that intragastric pressure measurement is potentially hazardous and might lead to inaccurately low intra-abdominal pressure values. This may result in missed diagnosis of elevated abdominal pressure or even ACS. The intravesical measurements showed the most accurate values during baseline pressure and both high-pressure plateaus.

Effects of different intra-abdominal pressure values on different organs: what should be the ideal pressure?

Background and purpose The control of intra-abdominal pressure (IAP) values clinically has gained considerable importance, as they affect organ functions and organ damage. Hence, the discussions on secure IAP values to be used in laparoscopic interventions still continue. In this study, the effects of low IAP values simultaneously on intrathoracic, intra-abdominal, and extra-abdominal organ damage are presented.

Pain medication requirements after sacropexy and combination interventions.

Background and Objectives:Laparoscopic surgery is associated with reduced morbidity, and postoperative pain is reduced. The aim of this study was to assess postoperative pain intensity, analgesic requirements, and the influence of cofactors after laparoscopic sacral colpopexy.Methods:The study assessed 287 patients treated with laparoscopic sacropexy for genital prolapse with a Pelvic Organ Prolapse Quantification grade >1. Patients were asked to evaluate their pain postoperatively using a 4-point verbal pain rating scale. In addition, medical records were analyzed regarding the requirement for analgesic medication.Results:Patients distinguished between abdominal pain and shoulder pain after laparoscopy. Abdominal pain reached maximum severity on day 1 and showed a good response to nonsteroidal antiphlogistics, whereas shoulder pain was rarely found (6.27%). Of the patients, 38% required no pain treatment or required 1 dose at most. The need for pain medication reached its climax on day 1 and decreased during the 5 following days. Non-opioid analgesics provided a sufficient therapeutic effect.Conclusion:Laparoscopic sacropexy is associated with a moderate degree of postoperative pain. Non-opioid analgesics should be preferred as first-line therapy. The typical shoulder-tip pain showed only a low prevalence in our study group. From our point of view, the low rate of shoulder-tip pain corresponded with the low intra-abdominal carbon dioxide pressure.

Optimizing working space in laparoscopy: CT measurement of the effect of pre-stretching of the abdominal wall in a porcine model

Determinants of working space in minimal access surgery have not been well studied. Using computed tomography (CT) to measure volumes and linear dimensions, we are studying the effect of a number of determinants of CO2 working space in a porcine laparoscopy model. Here we report the effects of pre-stretching of the abdominal wall. Earlier we had noted an increase in CO2 pneumoperitoneum volume at repeat insufflation with an intra-abdominal pressure (IAP) of 5 mmHg after previous stepwise insufflation up to an IAP of 15 mmHg. We reviewed the data of this serendipity group; data of 16 pigs were available. In a new group of eight pigs, we also explored this effect at repeat IAPs of 10 and 15 mmHg. Volumes and linear dimensions of the CO2 pneumoperitoneum were measured on reconstructed CT images and compared between the initial and repeat insufflation runs. Previous stepwise insufflation of the abdomen with CO2 up to 15 mmHg significantly (p < 0.01) increased subsequent working-space volume at a repeat IAP of 5 mmHg by 21 %, 7 % at a repeat IAP of 10 mmHg and 3 % at a repeat IAP of 15 mmHg. The external anteroposterior diameter significantly (p < 0.01) increased by 0.5 cm (14 %) at repeat 5 mmHg. Other linear dimensions showed a much smaller change. There was no statistically significant correlation between the duration of the insufflation run and the volume increase after pre-stretching at all IAP levels. Pre-stretching of the abdominal wall allows for the same surgical-field exposure at lower IAPs, reducing the negative effects of prolonged high-pressure CO2 pneumoperitoneum on the cardiorespiratory system and microcirculation. Pre-stretching has important scientific consequences in studies addressing ways of increasing working space in that its effect may confound the possible effects of other interventions aimed at increasing working space.

Effect of intra‐abdominal pressure on hepatic microcirculation: Implications of the endothelin‐1 receptor

To investigate the effect of endothelin receptor A (ET(A)) and endothelin receptor B (ET(B)) blockade on liver microcirculation and oxygenation during intra-abdominal pressure (IAP) increase. Fifteen anesthetized pigs were randomized to receive either nonselective endothelin-1 (ET-1) blocker tezosentan (TG, n = 7) or saline (CG, n = 8). Helium was insufflated to increase IAP from 0 to 25 mmHg. Stroke volume variability was maintained ≤ 12% with colloid infusion. Total liver blood flow (TLBF), hepatic microcirculatory blood flow (MBF), hepatic tissue oxygenation (HpO(2)), hyaluronic acid and plasma disappearance rate (PDR) of indocyanine green (ICG) were recorded. TLBF remained mostly unaltered in both groups at low IAP and decreased only in CG at the IAP of 25 mmHg. As IAP increased, a significant decline in MBF was observed without correlation with cardiac output or TLBF. In CG, HpO(2) decreased as early as IAP of 10 mmHg to high levels of pressure. However, in TG the decrease was significant only at the IAP of 25 mmHg. PDR of ICG decreased in both groups at IAP of 25 mmHg (P = 0.046 and P = 0.009 in TG and CG, respectively). These changes correlated with MBF (r = 0.793). Blocking ET(A) and ET(B) receptors partially protects sinusoidal circulation and tissue oxygenation against stress induced by high IAP.