The role of intra-abdominal pressure on splanchnic and pulmonary hemodynamic and metabolic changes during carbon dioxide pneumoperitoneum

Effect of intraabdominal hypertension on splanchnic blood flow in children with appendicular peritonitis

Background and Aims:

Intraabdominal hypertension (IAH) is poorly diagnosed condition that cause splanchnic hypoperfusion and abdominal organs ischemia and can lead to multiple organ failure. There are no scientific data regarding effect of intraabdominal pressure (IAP) on splanchnic circulation in children.

Material and Methods:

Ninety-four children after surgery for appendicular peritonitis were enrolled in the study. After IAP measurement children were included in one of two groups according IAP levels: “without IAH” (n = 51) and “with IAH” (n = 43). Superior mesenteric artery (SMA) and portal vein (PV) blood flows (BF_SMA, BF_PV, mL/min) were measured, and SMA and PV blood flow indexes (BFI_SMA, BFI_PV, ml/min*m2) and abdominal perfusion pressure (APP) were calculated in both groups.

Results:

Median BFI_SMA and BFI_PV in group “with IAH” were lower by 54.38% (P < 0.01) and 63.11% (P < 0.01) respectively compared to group “without IAH”. There were strong significant negative correlation between IAP and BFI_SMA (r_s = –0.66; P < 0.0001), weak significant negative correlation between IAP and BFI_PV (r_s = –0.36; P = 0.0001) in group “with IAH” and weak significant negative correlation between IAP and BFI_SMA (r_s = –0.30; P = 0.0047) in group “without IAH”. There were no statistically significant correlations between IAP and BFI_PV in group “without IAH”, between BFI_SMA and APP in both groups and between BFI_PV and APP in both groups.

Conclusion:

Elevated IAP significantly reduces splanchnic blood flow in children with appendicular peritonitis. BFI_SMA and BFI_PV negatively correlate with IAP in these patients. There is no correlation between BFI_SMA/BFI_PV and APP in children with IAH due to appendicular peritonitis.

Effects of laparoscopy, laparotomy, and respiratory phase on liver volume in a live porcine model for liver resection

Background

Hepatectomy, living donor liver transplantations and other major hepatic interventions rely on precise calculation of the total, remnant and graft liver volume. However, liver volume might differ between the pre- and intraoperative situation. To model liver volume changes and develop and validate such pre- and intraoperative assistance systems, exact information about the influence of lung ventilation and intraoperative surgical state on liver volume is essential.

Methods

This study assessed the effects of respiratory phase, pneumoperitoneum for laparoscopy, and laparotomy on liver volume in a live porcine model. Nine CT scans were conducted per pig (N = 10), each for all possible combinations of the three operative (native, pneumoperitoneum and laparotomy) and respiratory states (expiration, middle inspiration and deep inspiration). Manual segmentations of the liver were generated and converted to a mesh model, and the corresponding liver volumes were calculated.

Results

With pneumoperitoneum the liver volume decreased on average by 13.2% (112.7 ml ± 63.8 ml, p < 0.0001) and after laparotomy by 7.3% (62.0 ml ± 65.7 ml, p = 0.0001) compared to native state. From expiration to middle inspiration the liver volume increased on average by 4.1% (31.1 ml ± 55.8 ml, p = 0.166) and from expiration to deep inspiration by 7.2% (54.7 ml ± 51.8 ml, p = 0.007).

Conclusions

Considerable changes in liver volume change were caused by pneumoperitoneum, laparotomy and respiration. These findings provide knowledge for the refinement of available preoperative simulation and operation planning and help to adjust preoperative imaging parameters to best suit the intraoperative situation.

Reduction of Intra-abdominal Hypertension Is Associated with Increase of Cardiac Output in Critically Ill Patients Undergoing Mechanical Ventilation

Objective: To demonstrate the relationship between intra-abdominal hypertension (IAH) and cardiac output (CO) in mechanically ventilated (MV), critically ill patients.

Material and methods: This was a single-center, prospective study performed between January and April 2016, on 30 mechanically ventilated patients (mean age 67.3 ± 11.9 years), admitted in the Intensive Care Unit (ICU) of the Emergency County Hospital of Tîrgu Mureș, Romania, who underwent measurements of intra-abdominal pressure (IAP). Patients were divided into two groups: group 1 – IAP <12 mmHg (n = 21) and group 2 – IAP >12 mmHg (n = 9). In 23 patients who survived at least 3 days post inclusion, the variation of CO and IAP between baseline and day 3 was calculated, in order to assess the variation of IAP in relation to the hemodynamic status.

Results: IAP was 8.52 ± 1.59 mmHg in group 1 and 19.88 ± 8.05 mmHg in group 2 (p <0.0001). CO was significantly higher in group 1 than in the group with IAH: 6.96 ± 2.07 mmHg (95% CI 6.01–7.9) vs. 4.57 ± 1.23 mmHg (95% CI 3.62–5.52) (p = 0.003). Linear regression demonstrated an inverse correlation between CO and IAP (r = 0.48, p = 0.007). Serial measurements of CO and IAP proved that whenever accomplished, the decrease of IAP was associated with a significant increase in CO (p = 0.02).

Conclusions: CO is significantly correlated with IAP in mechanically ventilated patients, and IAH reduction is associated with increase of CO in these critically ill cases.

Arterioportal shunting, splanchnic capillary perfusion, and the effects of colloids during capnoperitoneum in neonatal and adolescent pigs

BACKGROUND

Clinical and experimental data indicate that neonates are sensitive to the CO₂ pneumoperitoneum. An impaired splanchnic perfusion during laparoscopy in adults has been reported. We recently confirmed that intravenous colloids improve macrocirculatory function in neonates. We aimed to determine the impact of CO₂ pneumoperitoneum on the perfusion of splanchnic organs in the young including effects of colloid application.

METHODS

Male piglets (n = 25) were divided into four groups: (1) neonatal controls, (2) neonates with crystalloid restitution, (3) neonates with colloidal restitution, and (4) adolescents with crystalloid restitution. Animals were ventilated and subjected to a 3-h, 10 mmHg CO₂ pneumoperitoneum followed by 2 h resuscitation. Hepatic, splanchnic, and arteriovenous shunt perfusion was assessed via central and portal venous catheters. Capillary organ flow was detected by fluorescent microspheres. The rate of bile flow was measured.

RESULTS

The neonatal crystalloid group showed a significant decrease in the intestinal capillary perfusion at the end of the recovery period. This was not detectable in the adolescent and colloid group. There was a significant increase in microcirculatory arterioportal shunt flow during the CO₂ pneumoperitoneum in both neonatal groups but not in the sham and adolescent groups (p < 0.05). Hepatic arterial perfusion increased after insufflation in all groups and dropped during capnoperitoneum to levels of about 70% baseline. There was no significant impairment of splanchnic perfusion or bile flow as a result of the pneumoperitoneum in all groups.

CONCLUSIONS

Capillary perfusion of the abdominal organs was stable during capnoperitoneum and recovery in adolescents and neonates with colloid restitution, but not with crystalloid restitution. Significant arterioportal shunting during capnoperitoneum could affect hepatic microcirculation in neonates. Our data confirm that moderate pressure capnoperitoneum has no major effect on the perfusion of abdominal organs in neonates with adequate substitution.

Hydrogen protects against liver injury during CO2 pneumoperitoneum in rats

The aim of the current study was to identify the protective effect of hydrogen gas against liver injury during CO₂ pneumoperitoneum. Rats were randomly divided into three groups: control group (C group), pneumoperitoneum group (P15 group) and hydrogen group (H₂ group). Rats in the C group were subjected to anesthesia for 90 min. Rats in the P15 group received an abdominal insufflation of CO₂ for 90 min at an intra-abdominal pressure of 15 mmHg. Rats in the H₂ group received a hypodermic injection of hydrogen gas (0.2 mL/kg) and after 10 min they received an abdominal insufflation of CO₂ for 90 min at an intra-abdominal pressure of 15 mmHg. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured to evaluate liver function. Malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) content were measured to evaluate oxidative stress. Nuclear factor E2-related factor 2 (Nrf2) and Nrf2 downstream target genes, apoptosis-related genes and inflammatory cytokine mRNA and protein expression were detected. Liver injury was detected under the microscope. Our results revealed that liver function, antioxidants content, inflammation and liver injury were improved after hydrogen preconditioning in H₂ group compared with P15 group. Overall, our results revealed that subcutaneous hydrogen injection could exert a protective effect against liver injury during CO₂ pneumoperitoneum through reducing oxidative stress, cell apoptosis and inflammatory cytokines release.

Variations of renal tissue oxygenation during abdominal compartment syndrome and sepsis

PURPOSE

This experimental study was designed to evaluate the renal tissue oxygenation under the coexistence of abdominal compartment syndrome and sepsis.

MATERIAL AND METHODS

Fourteen non-breed dogs were divided into two groups: the control group (8) and the study group (6). Sepsis was established with intravenous endotoxin infusion at 100μg/kg for over 30min. Insufflation of CO₂ in the peritoneal cavity was used for the increase in intra-abdominal pressure (IAP). A special catheter placed and fixed in the renal cortex at a depth of 3mm from the renal capsule was used for the measurement of renal tissue oxygenation.

RESULTS

Study parameters were recorded at the starting phase, at IAP of 15mmHg and 30mmHg and after decompression of the abdomen in the control group, and at the same intervals plus the induction of sepsis, prior to increasing abdominal pressure, in the study group. With the elevation of the IAP a reduction of renal tissue oxygenation presents itself, which is more pronounced in the presence of sepsis, especially for IAP over 15mmHg. Like other parameters, after abdominal decompression the renal tissue oxygenation returns to the initial levels, independently of sepsis.

CONCLUSIONS

The afferent arterioles vasoconstriction, which takes place during sepsis, and the intra-renal shunt, which occurs and leads to blood diversion to the medulla from the renal cortex due to the combination of intra-abdominal hypertension (IAH) and sepsis, seem to explain this finding.

Cardiovascular and Ventilatory Consequences of Laparoscopic Surgery

Although laparoscopic surgery accounts for >2 million surgical procedures every year, the current preoperative risk scores and guidelines do not adequately assess the risks of laparoscopy. In general, laparoscopic procedures have a lower risk of morbidity and mortality compared with operations requiring a midline laparotomy. During laparoscopic surgery, carbon dioxide insufflation may produce significant hemodynamic and ventilatory consequences such as increased intraabdominal pressure and hypercarbia. Hemodynamic insults secondary to increased intraabdominal pressure include increased afterload and preload and decreased cardiac output, whereas ventilatory consequences include increased airway pressures, hypercarbia, and decreased pulmonary compliance. Hemodynamic effects are accentuated in patients with cardiovascular disease such as congestive heart failure, ischemic heart disease, valvular heart disease, pulmonary hypertension, and congenital heart disease. Prevention of cardiovascular complications may be accomplished through a sound understanding of the hemodynamic and physiological consequences of laparoscopic surgery as well as a defined operative plan generated by a multidisciplinary team involving the preoperative consultant, anesthesiologist, and surgeon.

Gastrointestinal failure in the ICU

PURPOSE OF REVIEW

The current review summarizes different aspects of assessment of gastrointestinal function and provides a practical approach to management of adult patients with gastrointestinal dysfunction in the ICU.

RECENT FINDINGS

Different ways to define gastrointestinal failure have been used in the past. Recently, the term 'acute gastrointestinal injury (AGI)' has been proposed to specifically describe gastrointestinal dysfunction as a part of multiple organ dysfunction syndrome. Possible pathophysiological mechanisms and different aspects in assessment of gastrointestinal function in adult ICU patients are presented. Currently, there is no single marker that could reliably describe gastrointestinal dysfunction. Therefore, monitoring and management is still based on complex assessment of different gastrointestinal symptoms and feeding intolerance, even though this approach includes a large amount of subjectivity. The possible role of biomarkers (citrulline, enterohormones, etc.) and additional parameters like intra-abdominal pressure remains to be clarified.

SUMMARY

Defining gastrointestinal failure remains challenging but broad consensus needs to be reached and disseminated soon to allow conduct of interventional studies. A systematic approach to management of gastrointestinal problems is recommended.

Is there any effect of pneumoperitoneum pressure on coagulation and fibrinolysis during laparoscopic cholecystectomy?

Background

Laparoscopic cholecystectomies (LC) are generally performed in a 12 mmHg-pressured pneumoperitoneum in a slight sitting position. Considerable thromboembolism risk arises in this operation due to pneumoperitoneum, operation position and risk factors of patients. We aim to investigate the effect of pneumoperitoneum pressure on coagulation and fibrinolysis under general anesthesia.

Material and Methods

Fifty American Society of Anesthesiologist (ASA) I–III patients who underwent elective LC without thromboprophlaxis were enrolled in this prospective study. The patients were randomly divided into two groups according to the pneumoperitoneum pressure during LC: the 10 mmHg group (n = 25) and the 14 mmHg group. Prothrombin time (PT), thrombin time (TT), International Normalized Ratio (INR), activated partial thromboplastin time (aPTT) and blood levels of d-dimer and fibrinogen were measured preoperatively (pre), one hour (post1) and 24 h (post24) after the surgery. Moreover, alanine amino transferase, aspartate amino transferase and lactate dehydrogenase were measured before and after the surgery. These parameters were compared between and within the groups.

Results

PT, TT, aPTT, INR, and D-dimer and fibrinogen levels significantly increased after the surgery in both of the groups. D-dimer level was significantly higher in 14-mmHg group at post24.

Conclusion

Both the 10-mmHg and 14-mmHg pressure of pneumoperitoneum may lead to affect coagulation tests and fibrinogen and D-dimer levels without any occurrence of deep vein thrombosis, but 14-mmHg pressure of pneumoperitoneum has a greater effect on D-dimer. However, lower pneumoperitoneum pressure may be useful for the prevention of deep vein thrombosis.

Functional vascular anatomy of the peritoneum in health and disease

The peritoneum consists of a layer of mesothelial cells on a connective tissue base which is perfused with circulatory and lymphatic vessels. Total effective blood flow to the human peritoneum is estimated between 60 and 100 mL/min, representing 1-2 % of the cardiac outflow. The parietal peritoneum accounts for about 30 % of the peritoneal surface (anterior abdominal wall 4 %) and is vascularized from the circumflex, iliac, lumbar, intercostal, and epigastric arteries, giving rise to a quadrangular network of large, parallel blood vessels and their perpendicular offshoots. Parietal vessels drain into the inferior vena cava. The visceral peritoneum accounts for 70 % of the peritoneal surface and derives its blood supply from the three major arteries that supply the splanchnic organs, celiac and superior and inferior mesenteric. These vessels give rise to smaller arteries that anastomose extensively. The visceral peritoneum drains into the portal vein. Drugs absorbed are subject to first-pass hepatic metabolism. Peritoneal inflammation and cancer invasion induce neoangiogenesis, leading to the development of an important microvascular network. Anatomy of neovessels is abnormal and characterized by large size, varying diameter, convolution and blood extravasation. Neovessels have a defective ultrastructure: formation of large "mother vessels" requires degradation of venular and capillary basement membranes. Mother vessels give birth to numerous "daughter vessels". Diffuse neoangiogenesis can be observed before appearance of macroscopic peritoneal metastasis. Multiplication of the peritoneal capillary surface by neoangiogenesis surface increases the part of cardiac outflow directed to the peritoneum.

Ischemia modified albumin: does it change during pneumoperitoneum in robotic prostatectomies?

BACKGROUND

The unique positioning of the patient at steep Trendelenburg with prolonged and increased intra-abdominal pressure (IAP) during robotic radical prostatectomy may increase the risk of splanchnic ischemia. We aimed to investigate the acute effects of IAP and steep Trendelenburg position on the level of ischemia modified albumin (IMA) and to test if serum IMA levels might be used as a surrogate marker for possible covert ischemia during robotic radical prostatectomies.

PATIENTS AND METHODS

Fifty ASA I-II patients scheduled for elective robotic radical prostatectomy were included in this investigation.

EXCLUSION CRITERIA

The patients were excluded from the study when an arterial cannulation could not be accomplished, if the case had to be converted to open surgery or if the calculated intraoperative bleeding exceeded 300ml. All the patients were placed in steep (45 degrees) Trendelenburg position following trocar placement. Throughout the operation the IAP was maintained between 11-14mmHg. Mean arterial blood pressure (MAP), cardiac output (CO) were continuously monitored before the induction and throughout the surgery. Blood gases, electrolytes, urea, creatinine, alanine transferase (ALT), aspartate transferase (AST) were recorded. Additionally, IMA levels were measured before, during and after surgery.

RESULTS

(1) MAP, CO, lactate and hemoglobin (Hb) did not significantly change in any period of surgery (p>0.05); (2) sodium (p<0.01), potassium (p<0.05) and urea (p<0.05) levels decreased at postoperative period, and no significant changes at creatinine, AST, ALT levels were observed in these patients; (3) At the end of surgery (180 min) pCO2, pO2, HCO3 and BE did not change compared to after induction values (p>0.05) but mild acidosis was present in these patients (p<0.01 vs. after induction); (4) IMA levels were found to be comparable before induction (0.34±0.04), after induction (0.31±0.06) and at the end of surgery (0.29±0.05) as well.

CONCLUSION

We did not demonstrate any significant mesenteric-splanchnic ischemia which could be detected by serum IMA levels during robotic radical prostatectomies performed under steep Trendelenburg position and when IAP is maintained in between 11-14 mmHg.

Aprotinin reduces oxidative stress induced by pneumoperitoneum in rats

BACKGROUND

Ischemia-reperfusion injury induced by pneumoperitoneum is a well-studied entity, which increases oxidative stress during laparoscopic operations. The reported anti-inflammatory action of aprotinin was measured in a pneumoperitoneum model in rats for the first time in this study.

MATERIALS AND METHODS

A total of 60 male Albino Wistar rats were used in our protocol. Prolonged pneumoperitoneum (4 h) was applied, causing splanchnic ischemia and a period of reperfusion with a duration of 60 or 180 min followed. Several cytokines and markers of oxidative stress were measured in liver, small intestine, and lungs to compare the aprotinin group with the control group. Tissue inflammation was also evaluated and compared between groups using a five-scaled histopathologic score.

RESULTS

In aprotinin group values of biochemical markers (tumor necrosis factor α, interleukin 6, endothelin 1, C reactive protein, pro-oxidant-antioxidant balance, and carbonyl proteins) were lower in all tissues studied. Statistical significance was greater in liver and lungs (P < 0.05). Histopathologic examination revealed significant difference between control and aprotinin groups in all tissues examined. Aprotinin groups showed mild to moderate lesions, while in control groups severe to very severe inflammation was present. Aprotinin subgroup with prolonged reperfusion period (180 min) showed milder lesions in all tissues than the rest of the groups.

CONCLUSIONS

Aprotinin reduced inflammatory response and oxidative stress induced by pneumoperitoneum in liver, small intestine, and lungs.

Comparison of the duration of neuromuscular blockade following a single bolus dose of rocuronium during laparoscopic gynaecological surgery vs conventional open surgery

We investigated whether laparoscopic vs open surgical approaches affected the duration of neuromuscular blockade following a single bolus dose of rocuronium. Fifty-three female patients underwent either laparoscopic or open gynaecological surgery. Rocuronium 0.6 mg.kg(-1) was administered to achieve neuromuscular blockade in all subjects, and adductor pollicis train-of-four responses following ulnar nerve stimulation were monitored with mechanomyography. The mean (SD) time from injection of rocuronium until spontaneous recovery of the first twitch, and to 5% and 25% of baseline, was significantly prolonged in the laparoscopic group (27.2 (8.3) min, 31.3 (9.1) min and 38.1 (10.6) min, respectively) compared with the open surgery group (21.1 (5.8) min, 25.6 (6.3) min and 31.2 (6.7) min, respectively). Changes in liver function both before surgery and at 24 h postoperatively were similar between the two groups (p > 0.05). Our findings suggest that neuromuscular blockade may be prolonged following a single bolus dose of rocuronium given during laparoscopic procedures.

CO(2) pneumoperitoneum increases secretory IgA levels in the gut compared with laparotomy in an experimental animal model

BACKGROUND

Secretory immunoglobulin A (s-IgA) plays an important role in both gut and systemic immunity. This study aimed to investigate the production of s-IgA resulting from a CO2 pneumoperitoneum compared with a laparotomy.

METHODS

Using enzyme-linked immunosorbent assays, s-IgA in stool, malondialdehyde (MDA), and Toll-like receptor 4 (TLR4) in the ileal tissue were evaluated as markers for gut and systemic immune responses in an animal model. The rats were randomly divided into (i) anesthesia-only as the control group; (ii) laparotomy-only as the open group; and (iii) CO2 pneumoperitoneum-only as the pneumoperitoneum group. To evaluate the gut immune system in a time-dependent manner, each group was further divided into short- and long-time subgroups.

RESULTS

s-IgA levels did not increase in the open group but significantly increased in the pneumoperitoneum group compared with the control group (p < 0.05). In addition, s-IgA levels in the long-time subgroup significantly increased compared with the short-time subgroup of the pneumoperitoneum group (p < 0.05). TLR4 levels steeply and gradually increased in the open and pneumoperitoneum groups, respectively. MDA levels in the pneumoperitoneum group increased during the early phase and were significantly higher than those in the open group at 24 h (p < 0.05).

CONCLUSIONS

This study demonstrated that s-IgA levels in stool increased in the pneumoperitoneum group compared with the open group, suggesting that CO2 pneumoperitoneum may cause transitory damage to the intestinal mucosa.

The effect of dexmedetomidine on oxidative stress during pneumoperitoneum

Purpose. This study was intended to investigate the effect of dexmedetomidine on oxidative stress response in pneumoperitoneum established in rats. Methods. Animals were randomized into three groups, group S: with no pneumoperitoneum, group P: with pneumoperitoneum established, and group D: given 100 mcg intraperitoneal dexmedetomidine 30 min before establishment of pneumoperitoneum. Plasma total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI) activity were measured 30 min after conclusion of pneumoperitoneum. Results. The mean TOS level was significantly higher in group P than in the other two groups, and the TOS level was significantly higher in group D than in group S (P < 0.05). Plasma TAS level was found to be lower in group P than in the other two groups, and the TAS level was lower in group D than in group S (P < 0.05). Consequently, the OSI was significantly higher in group P than in groups D and S (P < 0.05). Conclusions. Ischemia-reperfusion phenomenon that occurs during pneumoperitoneum causes oxidative stress and consumption of plasma antioxidants. Dexmedetomidine decreases oxidative stress caused by pneumoperitoneum and strengthens the antioxidant defense system.

The effects of intra-abdominal hypertension on the secretory function of canine adrenal glands

Intra-abdominal hypertension (IAH) can damage multiple organ systems, but the explicit impact on the adrenal gland is unclear. To evaluate the effects of intra-abdominal pressure (IAP) on the secretory function of the adrenal glands, we established canine models of IAH. By comparing morphology; hemodynamics; plasma cortisol, aldosterone, epinephrine, and norepinephrine concentrations; and the expression of IL-1, IL-6, and TNF-α in adrenal gland tissue from these dogs, we found that hemodynamic instability occurred after IAH and that IAH increased the plasma cortisol, aldosterone, epinephrine, and norepinephrine concentrations. Higher IAPs resulted in more significant changes, and the above indicators gradually returned to normal 2 h after decompression. Compared with the sham-operated group, IAH significantly increased IL-1, IL-6, and TNF-α levels in adrenal tissue, with larger increases in the presence of higher IAPs. However, the concentrations of these markers remained higher than those in the sham-operated group despite their decrease after 2 h of decompression. Histopathological examination revealed congestion, red blood cell exudation, and neutrophil infiltration in the adrenal glands when IAP was elevated; these conditions became more significant with more severe IAH. These results suggest that the secretion of adrenal hormones and adrenal gland inflammation are positively correlated with IAP and that abdominal decompression effectively corrects adrenal gland function.

Intestinal ischemia following laparoscopic surgery: a case series

Introduction

Intestinal ischemia is a rare complication of laparoscopic surgery. Its prognosis depends on a high index of suspicion and effective early treatment.

Case presentation

In the present report, we describe three cases where intestinal ischemia developed following laparoscopic surgery. Case 1 concerns a 52-year-old Caucasian man who developed large bowel ischemia following laparoscopic adjustable gastric band surgery. Case 2 concerns an 82-year-old Caucasian woman who developed fatal intestinal ischemia following laparoscopic cholecystectomy. Case 3 concerns a 58-year old Caucasian woman who developed right-sided lower intestinal ischemia following open cholecystectomy.

Conclusions

Intestinal ischemia is a rare complication of laparoscopic surgery. The identification of high-risk patients is an essential primary preventive measure. A high index of suspicion is required to make an early diagnosis, which may help improve outcomes.

Low yield of significant findings on endoscopic retrograde cholangiopancreatography in patients with pancreatobiliary pain and no objective findings

BACKGROUND

Due to the challenging nature of the type III sphincter of the Oddi dysfunction (SOD) patient, the suspected low diagnostic yield from endoscopic retrograde cholangiopancreatography (ERCP), the high complication rate, and the potential for litigation it is surprising that diagnostic ERCP continues to be performed in this patient population.

AIMS

The purpose of this study was to determine the incidence of significant findings on ERCP alone in patients with disabling abdominal pain of suspected pancreatobiliary origin and no objective findings.

METHODS

Entry criteria of this study included: (1) ERCP with attempt at visualization of both the biliary tree and pancreatic duct, (2) suspected of having abdominal pain of pancreatobiliary origin, (3) biliary or pancreatic type III by the modified Geenen-Hogan classification, (4) never undergone sphincterotomy, (5) attempted manometry of both sphincters. A total of 265 patients met entry criteria.

RESULTS

Significant findings were found in seven patients (2.6 %): choledococoele (1), anomalous pancreatobiliary ductal union (2), mild-moderate chronic pancreatitis (2), and pancreatic duct filling defect suspicious for IPMN (2). Potentially significant in 25 patients (9.4 %) were: equivocal chronic pancreatitis (1), incomplete (4) and complete pancreas divisum (20). SOD was diagnosed in 77.7 %. 11.3 % had undergone a previous diagnostic ERCP.

CONCLUSION

ERCP in this high-risk population requires detailed informed consent, availability of SOM to increase the diagnostic yield, and skills in placing prophylactic pancreatic stents. It is our belief that patients without objective findings of pancreatobiliary disease that would explain their subjective complaints should not undergo diagnostic ERCP.

The oxidative effect of prolonged CO(2) pneumoperitoneum a comparative study in rats

BACKGROUND

The current study evaluated the effect of time in the severity of the oxidative stress due to pneumoperitoneum.

METHODS

Forty Wistar rats were allocated randomly into 2 groups. The 1 h pneumoperitoneum (Pp) group, which was subjected to 60 min of pneumoperitoneum, and the 3 h Pp, to pneumoperitoneum for 180 min. The animals were divided in half. One half of the rats were left resting for 30 min after abdominal desufflation and the other for 8 h. After these two time periods, blood, liver, kidney, lung and small intestine were obtained for biochemical analysis and histopathological examination.

RESULTS

In the 3 h Pp, the associated oxidative stress was increased. There was an overt increase in blood and tissue MDA and blood PAB values. The MPO values were significantly higher in the 3 h Pp group in serum, kidneys, and intestine during the early phase of reperfusion and in liver after 8 h of reperfusion. These changes occurred in the presence of light microscopic evidence of greater tissue damage for the 3 h Pp, which were consistent with the fluctuation of the MPO values.

CONCLUSION

In our experimental model, we proved biochemically and histologically that time of maintenance of pneumoperitoneum is an additive factor that could cause increased oxidative stress in laparoscopic procedures.

The effects of different insufflation pressures on liver functions assessed with LiMON on patients undergoing laparoscopic cholecystectomy

Purpose. Laparoscopic cholecystectomy has been accepted as an alternative to laparotomy, but there is still controversy regarding the effects of pneumoperitoneum on splanchnic and hepatic perfusion. We assessed the effects of different insufflation pressures on liver functions by using indocyanine green elimination tests (ICG-PDR). Methods. We analyzed 43 patients who were scheduled for laparoscopic cholecystectomy. The patients were randomly allocated to two groups. In Group I, the operation was performed using 10 mmHg pressure pneumoperitoneum. In Group II, 14 mmHg pressure pneumoperitoneum was used. The ICG-PDR measurements were made after induction (ICG-PDR 1) and after the end of the operation (ICG-PDR 2). Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin levels were all recorded preoperatively, 1 hour, and postoperative 24 hours after surgery. Results. The ICG-PDR 1 values for Groups I and II were as follows: 26.78 ± 4.2% per min versus 26.01 ± 2.4% per min (P > 0.05). ICG-PDR 2 values were found to be 25.63 ± 2.1% per min in Group I versus 19.06 ± 2.2% per min in Group II (P < 0.05). There was a statistically significant decrease between baseline and postoperative ICG-PDR values in Group II compared to Group I (P < 0.05). Statistically, there was an increase between baseline and postoperative 1st-hour serum AST and ALT level in Group II (P < 0.05) compared to Group I. No statistical differences were detected on postoperative 24st-hour serum AST and ALT levels and all the time bilirubin between groups (P > 0.05). Conclusion. In conclusion, the results show that 14 mmHg pressure pneumoperitoneum decreased the blood flow to the liver and increased postoperative 1st-hour serum AST and ALT levels. We think that 10 mmHg pressure pneumoperitoneum is superior to 14 mmHg pressure pneumoperitoneum in laparoscopic cholecystectomy.

Relationship between Abdominal Pressure, Pulmonary Compliance, and Cardiac Preload in a Porcine Model

Rationale. Elevated intra-abdominal pressure (IAP) may compromise respiratory and cardiovascular function by abdomino-thoracic pressure transmission. We aimed (1) to study the effects of elevated IAP on pleural pressure, (2) to understand the implications for lung and chest wall compliances and (3) to determine whether volumetric filling parameters may be more accurate than classical pressure-based filling pressures for preload assessment in the setting of elevated IAP. Methods. In eleven pigs, IAP was increased stepwise from 6 to 30 mmHg. Hemodynamic, esophageal, and pulmonary pressures were recorded. Results. 17% (end-expiratory) to 62% (end-inspiratory) of elevated IAP was transmitted to the thoracic compartment. Respiratory system compliance decreased significantly with elevated IAP and chest wall compliance decreased. Central venous and pulmonary wedge pressure increased with increasing IAP and correlated inversely (r = -0.31) with stroke index (SI). Global end-diastolic volume index was unaffected by IAP and correlated best with SI (r = 0.52). Conclusions. Increased IAP is transferred to the thoracic compartment and results in a decreased respiratory system compliance due to decreased chest wall compliance. Volumetric filling parameters and transmural filling pressures are clearly superior to classical cardiac filling pressures in the assessment of cardiac preload during elevated IAP.

Antioxidant prophylaxis for cellular injury in ovarian surface epithelium resulting from CO₂ pneumoperitoneum in a laparoscopic rat model

OBJECTIVE

Selective cytoprotective functions of vitamin E, N-acetyl-L: -cysteine, and amifostine have been used as a preventer of ischemia injury by expelling the free oxygen radicals leading to stabilization of the cellular membranes. The purpose of this experimental study was to investigate the oxidative stress related to cellular injury in ovarian surface epithelium and the effect of prophylaxis with an anti-oxidant using laparoscopic rat model.

DESIGN

Laparoscopic rat model.

MATERIALS AND METHODS

Randomly allocated 40 Wistar Albino female rats have been used for the pneumoperitoneum model which was constituted to fix the intraabdominal pressure on 5 mmHg for 60 min. The antioxidants, vitamin E and NAC were given to rats 3 days before the operation and were applied for 30 days; amifostine was applied 30 min before the operation until after for 7 days. After abdominal desufflation, over biopsies were made on the 13th min, 24th h, and 7th and 30th days. By using of transmission electron microscopy, the damage on cells and organels were assessed and graded.

RESULTS

In ovarian surface epithelium, the apical surface specializations were affected in all groups except Vit E group:The microvilli were irregular and coarse and had disappeared in some places. Some cells were separated from the epithelium. In addition, mitochondria degeneration was observed in all group except Vit E.

CONCLUSIONS

In the early period of laparoscopy, reversible cellular damage occurs and this damage can be prevented by vitamin E.

Warming and humidification have no effect on oxidative stress during pneumoperitoneum in rats

Pneumoperitoneum is reported to induce oxidative stress due to the desiccative effect of cold, dry gas insufflation. The aim of this study is to compare the effect of warmed, humidified insufflation to standard gas, by measuring oxidative stress markers in a physiologically relevant animal model. Twenty male Wistar rats (330?650 g) were alternately assigned to the Warm Humidified group (WH, n = 10) and Control group (n = 10). All rats underwent pneumoperitoneum at 5 mmHg and a controlled flow rate for 110 min. The WH group received warmed (37?C) and humidified (98% Relative Humidity (RH)) gas and the control group received standard gas at room temperature (19?C) and 0% RH. At the end of pneumoperitoneum, samples of liver, kidney, pancreas, jejunum, and lung were excised. Levels of plasma and tissue malondialdehyde (MDA) and protein carbonyls (PC) were measured. Organ light microscopy was performed. There were no differences between groups for MDA or PC concentrations in plasma, liver, kidney, jejunum, or lung tissue. There were no differences in histological score between groups. Warming and humidification of pneumoperitoneum insufflation gas have no effect on measures of oxidative stress compared to non-warmed, non-humidified controls.

Increasing abdominal pressure with and without PEEP: effects on intra-peritoneal, intra-organ and intra-vascular pressures

BACKGROUND

Intra-organ and intra-vascular pressures can be used to estimate intra-abdominal pressure. The aim of this prospective, interventional study was to assess the effect of PEEP on the accuracy of pressure estimation at different measurement sites in a model of increased abdominal pressure.

METHODS

Catheters for pressure measurement were inserted into the stomach, urinary bladder, peritoneal cavity, pulmonary artery and inferior vena cava of 12 pigs. The pressures were recorded simultaneously at baseline, during 10 cm H20 PEEP, external abdominal pressure (7 kg weight) plus PEEP, external abdominal pressure without PEEP, and again under baseline conditions. RESULTS (MEAN +/- SD): PEEP alone increased diastolic pulmonary artery and inferior vena cava pressure but had no effect on the other pressures. PEEP and external abdominal pressure increased intraperitoneal pressure from 6 +/- 1 mm Hg to 9 +/- 2 mm Hg, urinary bladder pressure from 6 +/- 2 mm Hg to 11 +/- 2 mm Hg (p = 0.012), intragastric pressure from 6 +/- 2 mm Hg to 11 +/- 2 mm Hg (all p

CONCLUSIONS

Our data suggest that pressure changes induced by external abdominal pressure were not modified by changing PEEP between 0 and 10 cm H20.

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MESH Headings

• Abdomen/physiology
• Animals
• Female
• Models, Animal
• Peritoneal Cavity/physiology
• Positive-Pressure Respiration
• Pressure
• Pulmonary Artery/physiology
• Stomach/physiology
• Swine
• Urinary Bladder/physiology
• Vena Cava, Inferior/physiology

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Affiliation(s)

Stephan M Jakob Department of Intensive Care Medicine, University Hospital (Inselspital) and University of Bern, Bern, Switzerland
Rafael Knuesel Department of Intensive Care Medicine, University Hospital (Inselspital) and University of Bern, Bern, Switzerland
Jyrki J Tenhunen Department of Intensive Care Medicine, Kuopio University Hospital, Kuopio, Finland
Richard Pradl Department of Intensive Care Medicine, Kuopio University Hospital, Kuopio, Finland
Jukka Takala Department of Intensive Care Medicine, University Hospital (Inselspital) and University of Bern, Bern, Switzerland

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Comparative study between clipless laparoscopic cholecystectomy by harmonic scalpel versus conventional method: a prospective randomized study

BACKGROUND

This study was planned to compare the traditional method of laparoscopic cholecystectomy (LC) versus LC using harmonic as regard the safety and efficacy.

MATERIAL AND METHODS

This study included group A (70 patients) in whom LC was conducted using the traditional method (TM) by clipping both cystic duct and artery and dissection of gallbladder from liver bed by diathermy, and group B (70 patients) LC was conducted using harmonic scalpel (HS) closure and division of both cystic duct and artery and dissection of gallbladder from liver bed by HS. The intraoperative and postoperative parameters were collected including duration of operation, postoperative pain, and complications.

RESULTS

HS provides a shorter operative duration than TM (33.21 + 9.6 vs. 51.7 + 13.79, respectively, p = 0.001), with a significant less incidence of gallbladder peroration (7.1% vs. 18.6, p = 0.04) and less rate of conversion to open cholecystectomy but not reach a statistical significance. The amount of postoperative drainage is significantly less in HS (29 + 30 vs. 47.7 + 31, p = 0.001). No postoperative bile leak was encountered in HS, but it occurred in 2.9% of patients in TM. VAS in HS at 12 h postoperative was 3.25 + 1.84 vs 5.01 + 1.2 (p = 0.001) and at 24 h postoperative was 3.12 + 1.64 vs. 4.48 + 1.89 (p = 0.001).

CONCLUSION

HS provides a complete hemobiliary stasis and is a safe alternative to stander clip of cystic duct and artery. It provides a shorter operative duration, less incidence of gallbladder perforation, less postoperative pain, and less rate of conversion to open cholecystectomy.

Influência do pneumoperitônio nas funções hepática e renal e na liberação de citocinas pró-inflamatórias em modelo experimental de endotoxemia induzida por lipopolissacarídeo de Escherichia coli

RACIONAL: A videocirurgia pode apresentar complicações inerentes ao método e dentre elas destacam-se as relacionadas ao aumento da pressão na cavidade intra-abdominal. OBJETIVO: Analisar os efeitos do pneumoperitônio em modelo experimental de endotoxemia causada por lipopolissacarídeo. MÉTODO: Foram utilizados 32 ratos Wistar dos quais foi coletado sangue 24 horas prévias para obtenção dos valores de referência nas provas de função renal, hepática e do estado endotóxico (contagens total e diferencial de leucócitos, contagem de plaquetas e dosagens de lipopolissacarídeo, TNFα, IL6). A seguir os ratos foram separados em quatro grupos com oito: grupos controle inoculados com lipopolissacarídeo (10 mg/kg via intraperitoneal) e mantidos por quatro e 11 horas (C-LPS4 e C-LPS11). Grupo C-PP, submetido ao pneumoperitônio por CO2 por uma hora e mantido sob observação por seis horas. Grupo experimento (E) inoculados com 10 mg/kg de lipopolissacarídeo por via intraperitoneal, após quatro horas submetidos ao pneumoperitônio por CO2 por uma hora e mantidos sob observação por seis horas. Ao término destes períodos foram coletadas amostras de sangue para as mesmas avaliações iniciais. Utilizou-se o método de T-Student para as comparações dos resultados, com nível de significância de 0,05. RESULTADOS: Em comparação aos valores iniciais e aos grupos controle, o grupo E apresentou maiores valores nas dosagens de creatinina e uréia, bilirrubina direta, ALT e TAP, aumento nas dosagens de IL6, TNFα e diminuição de plaquetas, aumento de leucócitos e bastonetes e detecção de endotoxina circulante. CONCLUSÃO: O pneumoperitônio por dióxido de carbono induz aumentos na liberação de TNFα, IL6, piora das funções hepática e renal em modelo experimental de endotoxemia induzida por lipopolissacarídeo.

The correlation between reactive oxygen species and histopathology of the liver, gut, and kidneys in animals with elevated intra-abdominal pressure

BACKGROUND

Clinical and experimental studies have shown that the laparoscopic procedure provides a typical model of ischemia-reperfusion injury in the organs by oxygen-derived free radicals. A pneumoperitoneum produces ischemia during insufflation and reperfusion during desufflation. The aim of this study was to assess the causative role of free radical-mediated reactions in tissue damage under different intra-abdominal insufflation pressures.

MATERIALS AND METHODS

Thirty five mature New Zealand white rabbits were assigned to three groups of 10 animals. In groups 1, 2, and 3, the designated pressures of 10, 15, and 20 mm Hg, respectively. The remaining 5 animals underwent laparotomy, using a 10-cm midline incision taken as group 4 (control). Blood samples were collected before (0 minutes) and at the end of the procedure (60 minutes). After the collection of the last blood samples, all animals were sacrificed and the samples from the liver, kidney, and gut were obtained for histologic evaluation and also measurements of tissue malondialdehyde (MDA) levels.

RESULTS

The nitric oxide levels were not changed in groups 1 and 2, but increased significantly in group 3. Tissue MDA levels were significantly higher in groups 1 and 2 than groups 3 and 4. Histopathologic examination of the kidney revealed some findings of reversible hypoxic cell injury, including acute cellular swelling, vascular congestion, and some early findings of irreversible injury, such as lysis of the cytoplasmic membrane in all groups and focal parancymal bleeding area in only group 3 as a consequence of increased pressure. Liver histology revealed cellular swelling and karyorhexis in hepatocytes in group 1, whereas only congestion and sinusoidal dilatation was observed in groups 2 and 3.

CONCLUSION

Our experimental study showed that abdominal insufflation causes ischemia and free radical production, which seems responsible for the cell damage that occured during laparoscopic surgery.

Systematic review of oxidative stress associated with pneumoperitoneum

Background

There have been several reports of ischaemic complications after routine laparoscopy. The aim of this review was to investigate the relationship between this oxidative stress and pneumoperitoneum.

Methods

Medline, Medline in-process, The Cochrane Library, PubMed and EMBASE were searched for papers on oxidative stress and pneumoperitoneum, from 1947 to March 2008 with no language restriction or restriction on trial design. Papers that did not investigate pneumoperitoneum as a causative factor, or did not report outcome measures related to oxidative stress, were excluded.

Results

A total of 73 relevant papers were identified: 36 animal studies, 21 human clinical trials, nine case reports, five review articles and two comments. Pneumoperitoneum causes a reduction in splanchnic blood flow, resulting in biochemical evidence of oxidative stress in a pressure- and time-dependent manner. There is evidence that the use of carbon dioxide for insufflation is contributory. Several measures proposed to minimize the oxidative stress have shown promise in animal studies, but few have been evaluated in the clinical setting.

Conclusion

There is an increasing body of evidence, mainly from animal studies, that pneumoperitoneum decreases splanchnic perfusion with resulting oxidative stress. It is now appropriate to investigate the clinical significance of pneumoperitoneum-associated oxidative stress.

Abdominal compartment syndrome

Increased intra-abdominal pressure (IAP) has received growing attention in critically ill patients. Pathophysiologically, it deranges cardiovascular haemodynamics, respiratory and renal functions and may eventually lead to multi-organ failure. It is primarily seen in surgical intensive care units and is frequently associated with abdominal trauma but also occurs after elective abdominal surgery. Non-surgical intensivists ought to be aware that the syndrome is also seen in a wide spectrum of medical conditions, e.g. acute pancreatitis. An expert panel has recently set up definitions of intra-abdominal hypertension (IAH, sustained or repeated pathological elevation in IAP > or = 12 mmHg) and abdominal compartment syndrome (ACS, sustained IAP > 20 mmHg associated with a new organ dysfunction or failure). As clinical signs of IAH are unreliable, IAP should be measured non-invasively by the 'bladder technique'. It is hoped that the consensus definitions will contribute to a broader recognition and effective treatment of this life-threatening syndrome.

Mesna protects splanchnic organs from oxidative stress induced by pneumoperitoneum

BACKGROUND

We investigated the potential beneficial effect of the antioxidant 2-mercaptoethane-sulfonate (mesna) against oxidative stress induced by pneumoperitoneum in splanchnic organs.

METHODS

Wistar rats were subjected to either (a) CO(2) pneumoperitoneum (15 mmHg for 60 min) (group P), (b) pretreatment with mesna (400 mg/kg, p.o.) followed by pneumoperitoneum with a 180 min interval (group MP), (c) sham operation (group S), or (d) administration of mesna only (group M). Forty-five minutes after desufflation (groups P and MP), 60 + 45 min after the induction of anesthesia (group S), or 180 min after mesna administration (group M), tissue specimens were excised from liver, kidneys, jejunum and stomach. Tissue oxidative state was assessed on the basis of glutathione-to-glutathione disulfide ratio, malondialdehyde concentration , and superoxide dismutase activity.

RESULTS

Pneumoperitoneum deteriorated all the oxidative stress markers in the organs studied. Mesna prevented the occurrence of oxidative stress following pneumoperitoneum in all the organs studied. In the absence of pneumoperitoneum, the administration of mesna caused mild enhancement of the oxidative state of liver, stomach, and kidneys compared to sham controls.

CONCLUSIONS

Prophylaxis with mesna prevents oxidative stress induced by pneumoperitoneum in splanchnic organs.

Liver histology alterations during carbon dioxide pneumoperitoneum in a porcine model

BACKGROUND

This study aimed to investigate the time course changes in liver histology during carbon dioxide (CO(2)) pneumoperitoneum in a large animal model.

METHODS

For this study, 14 white pigs were anesthetized. Liver biopsies performed 0, 1, and 2 h after establishment of CO(2) pneumoperitoneum (at 12 mmHg) and after peritoneal desufflation were sent for histologic examination. Heart rate, mean blood pressure, hepatic artery flow, portal vein flow, and aortic flow were recorded in 10-min increments. Three animals served as control subjects.

RESULTS

A statistically significant time course increase was observed in portal inflammation, intralobular inflammation, edema, sinusoidal dilation, sinusoidal hyperemia, centrilobular dilation, centrilobular hyperemia, pericentrilobular ischemia, and focal lytic necrosis scores. There were no significant changes in the control group. This eliminated an effect of anesthesia only. The portal vein flow increased as much as 21%, and the hepatic artery flow decreased as much as 31% of baseline, but these differences did not attain statistical significance. Aortic flow remained relatively stable.

CONCLUSION

Histomorphologic changes occurred, indicating liver tissue injury during CO(2) pneumoperitoneum at an intraabdominal pressure of 12 mmHg in the porcine model. Portal vein flow increased, and hepatic artery flow decreased, whereas aortic flow remained relatively unaffected in this experiment.

Laparoscopic cholecystectomy with carbon dioxide pneumoperitoneum is safe even for high-risk patients

BACKGROUND

Because of absorbed carbon dioxide (CO(2)) and elevated intraabdominal pressure (IAP), CO(2) pneumoperitoneum (CO(2)PP) has potentially harmful intraoperative circulatory and ventilatory effects. Although not clinically significant for healthy patients, these effects are assumed to be deleterious for patients with a high risk for anesthesia (American Society of Anesthesiology [ASA] 3 and 4) and significant cardiopulmonary, renal, or hepatic diseases. The authors assessed CO(2)PP-related adverse effects by comparing ASA 3 and 4 patients who underwent laparoscopic cholecystectomy (LC) with or without CO(2)PP.

METHODS

A total of 20 successive ASA 3 and 4 patients who underwent LC were randomized into CO(2)PP (n = 10) and abdominal wall elevator (Laparolift) (n = 10) groups. The parameters for perioperative hemodynamics, ventilation, perfusion of intraabdominal organs, and blood chemistry were recorded periodically from before the induction of the anesthesia until postoperative day 2 and compared between the groups.

RESULTS

Mean age, height, weight, the proportional number of ASA 3 vs ASA 4 patients, the volume of perioperative fluid loading, and the dose of analgesics did not differ significantly between the groups. The length of the operation was 49.9 +/- 10.6 min for the CO(2)PP group and 50.6 +/- 17.2 min for Laparolift group (nonsignificant difference). The mean central venous pressure (CVP) 30 min after insufflation was higher (12.3 +/- 4.8 vs 7.9 +/- 3.7 mmHg) and the (Gastric Mucosal pH) pHi at the end of the operation was lower (7.29 +/- 0.07 vs 7.35 +/- 0.04) in the CO(2)PP group than in the Laparolift group (p < 0.05). Later, CVP and pHi did not differ significantly. Other parameters of hemodynamics including oxygenation, perfusion, and blood chemistry did not differ significantly.

CONCLUSIONS

For LC for patients with an ASA 3 and 4 risk for anesthesia, no significant adverse effects could be attributed to CO(2 )pneumoperitoneum. For high-risk patients, preoperative preparation and active perioperative monitoring are essential for safe anesthesia for LC with or without CO(2)PP.

Abdomino-thoracic transmission during acs: facts and figures

Elevated intra-abdominal pressure (IAP) exerts effects not only on intra-abdominal organs, but also on organs distant to the abdominal compartment. Abdomino-thoracic interaction during intra-abdominal hypertension (IAH) or abdominal compartment syndrome (ACS) interferes with pulmonary, cardiovascular and cerebral function. In accordance with recent guidelines, IAH is defined as IAP above 12 mmHg and ACS as IAP more than 20 mmHg with one or more new organ failures. In this review we will first discuss the effects of elevated IAP on pulmonary dynamics and the relevance for interpreting airway pressures and adjusting ventilator settings. We will then discuss the interaction between abdomino-thoracic pressure transmission and global haemodynamics, the knowledge of which is necessary for correct assessment of cardiac preload and to optimize fluid therapy in the setting of IAH/ACS. A discussion on the relationship between increased IAP, increased intracranial pressure (ICP) and decreased cerebral perfusion pressure (CPP) will follow. Finally, we will review ventilator-induced thoracic pressure swings and their transmission to the abdominal compartment.

[Abdominal compartment syndrome]

Abdominal compartment syndrome (ACS) is characterized by a persistent pathologic increase in intra-abdominal pressure (IAP) exceeding 20 mmHg with consecutive dysfunction of multiple organ systems. The main causes of ACS are abdominal trauma, obstruction, infection, and sepsis, but it may also be initiated by extra-abdominal diseases. The gold standard for diagnosis is repeated assessment of the IAP measurements of bladder pressure. The incidence of ACS is up to 15% in operative ICUs and the therapy of choice for it is decompressive laparotomy. Nevertheless, mortality is high, up to 60%.

Does Anti-Oxidant Prophylaxis with Melatonin Prevent Adverse Outcomes Related to Increased Oxidative Stress Caused by Laparoscopy in Experimental Rat Model?

BACKGROUND

We hypothesized that prophylaxis with an anti-oxidant should prevent potential adverse outcomes of laparoscopy related to increased oxidative stress in splanchnic organs, including small intestine, liver, and kidneys, and melatonin is the most appropriate agent for this purpose.

METHODS

Twenty-four Sprague-Dawley rats weighing 300 to 350 g were allocated randomly into three groups consisting of eight in each as follows: Group I: gasless (control); group II: 15 mmHg intraabdominal pressure (IAP) with CO2 pneumoperitoneum for 60 min; group III: 15 mmHg IAP with CO2 pneumoperitoneum for 60 min, and melatonin (10 mg/kg) was administered at two occasions, 5 min before insufflation and immediately before the desufflation. In group II and III, rats left resting for 30 min after abdominal deflation, the small intestine (terminal ileum), liver and kidney examples were excised from same locations. The specimens were also obtained using the same time points in group I rats, comprising the control group. The specimens were immediately placed at -80 degrees C for the malondialdehyde (MDA) measurements. In addition, segments of terminal ileum were taken from the similar places in all of the animals for the histological examinations.

RESULTS

Comparisons among the groups revealed that highest mean MDA levels in liver, small intestine and kidney were in the group II, followed by the group III and control group. There was significant difference between mean MDA levels in small intestine, liver and kidney of group II and III (P < 0.0005). However, no significant difference was found between mean MDA levels in small intestine, liver, and kidney of the group III and control group. Mucosa and submucosa were affected significantly in 15 mmHg IAP group (no prophylaxis) when compared with the control and melatonin prophylaxis groups (P = 0.002). However, there was not a significant difference in mean damage score of mucosa, submucosa, and muscular layers in control group when compared to melatonin prophylaxis group.

CONCLUSIONS

This experimental study indicated that melatonin prophylaxis, with anti-oxidant and anti-inflammatory actions, may have an important role in the prevention of potential complications related to oxidative stress injury on splanchnic organs induced by laparoscopy.

Effects of increased intra-abdominal pressure on central circulation

BACKGROUND

In an experimental model we investigated the effects of a gradual increase in intra-abdominal pressure (IAP) on the central circulation.

METHODS

Seven pigs were anaesthetized, mechanically ventilated and instrumented. IAP was gradually increased by 5 mm Hg up to 30 mm Hg by abdominal banding in normovolaemic animals, and then they were made hypovolaemic after blood withdrawal. Right atrial pressure (RAP) and left ventricular end-diastolic pressure (LVEDP) at each step and aortic, femoral and inferior vena cava blood flows were measured. Left ventricular end-diastolic area (LVEDA) was determined using epicardial echocardiography.

RESULTS

Cardiac output maintained at mild IAP was reduced to 76 (24)% of the initial value at 30 mm Hg IAP [mean (sd)] in normovolaemic animals, and 72 (22)% (P<0.001) in hypovolaemic animals. In normovolaemic animals the LVEDA and LVEDP were significantly increased at an IAP of 10 and 15 mm Hg by 26 (24)% and 38 (23)%, respectively. At these IAP values, the difference between the RAP and IAP was positive. When this gradient became negative, that is beyond 15 mm Hg in normovolaemia and for all IAP values in hypovolaemic animals, the LVEDA declined, reaching 78 (16)% and 62 (22)% (P<0.05) of the initial values in normovolaemic and hypovolaemic groups at the highest IAP value.

CONCLUSIONS

These results showed that a gradual increase in IAP led to a redistribution of abdominal blood volume towards the thoracic compartment, at IAP lower than 15 mm Hg in normovolaemia, and at its expense at higher values of IAP. In hypovolaemia there was no thoracic compartment gain. Whereas the absolute or transmural RAPs were not informative of the direction of this blood shift, an RAP greater than IAP was associated with an intrathoracic compartment gain.

Myelofibrosis-associated massive splenomegaly: a cause of increased intra-abdominal pressure, pulmonary hypertension, and positional dyspnea

We describe a patient with myelofibrosis, giant splenomegaly, and pulmonary hypertension related to increased intra-abdominal pressure. Focusing on alterations in hemodynamic studies, we conclude that in patients with myelofibrosis, dyspnea, and hypoxemia, the measurement of intra-abdominal pressure should be included in the initial evaluation. It is an inexpensive, non-invasive diagnostic tool that can provide crucial information about the cause of dyspnea and disclose the pathogenetic link between massive splenomegaly and pulmonary compromise in myelofibrosis.

O papel do pneumoperitônio na avaliação de parâmetros respiratórios e hemodinâmicos de ratos anestesiados, com ou sem intubação intratraqueal

OBJETIVO: Estudar as alterações hemodinâmicas e respiratórias em ratos submetidos ou não ao pneumoperitônio com CO2, sob anestesia com ou sem intubação intratraqueal. MÉTODO: Ratos machos (n = 40), albinos, com peso médio de 300g, idade de três meses, foram randonizados em quatro grupos: GA - anestesia com intubação endotraqueal por uma hora e com pneumoperitônio de 4mmHg de CO2; GB - anestesia sem intubação endotraqueal por uma hora e com pneumoperitônio de 4mmHg de CO2; GC - anestesia sem intubação endotraqueal por uma hora e sem pneumoperitônio; GD - anestesia com intubação endotraqueal por uma hora, sem pneumoperitônio. Foram registrados os valores da pressão arterial média (PAM), pressão parcial de gás carbônico (pCO2), freqüência cardíaca (FC), freqüência respiratória (FR), pressão venosa central (PVC), potencial hidrogeniônico acidose (pH), saturação de oxigênio periférico (spO2), bicarbonato (HCO3-) e saturação de oxigênio no sangue arterial (SO2,). Os dados foram coletados no início do experimento (M0), após 30 minutos (M1) e após 60 minutos (M2). RESULTADOS: Em GA e GC (grupos com pneumoperitônio) ocorreu aumento da PAM, PCO2, HCO3-, FR, PVC e uma diminuição do pH, SO2, spO2 e da FC em relação aos animais sem pneumoperitônio. Por outro lado a intubação intratraqueal demonstrou atenuar estas alterações nos animais com até uma hora de anestesia. CONCLUSÃO: A anestesia geral com intubação endotraqueal associada ao pneumoperitônio de 4mmHg, por um período de uma hora, mostrou vantagens do ponto de vista respiratório e hemodinâmico, em relação aos animais com pneumoperitônio e sem intubação e também sobre aqueles com até quatro horas de anestesia, apesar da intubação.

Intra-abdominal hypertension in the critically ill: it is time to pay attention

PURPOSE OF THE REVIEW

There has been an exponentially increasing interest in intra-abdominal hypertension (IAH). Comparison of the published data however is difficult due to the lack of consensus definitions. This review will focus on the available literature from the last 2 years. A Medline and PubMed search was performed using 'intra-abdominal pressure' (IAP), 'intra-abdominal hypertension' (IAH), and 'abdominal compartment syndrome' (ACS) as search items. The aim was to find an answer to the question 'Isn't it time to pay attention to intra-abdominal pressure in the critically ill?'

RECENT FINDINGS

Although the number of studies published on this topic is steadily increasing and confirms the pathophysiologic implications of IAH on end-organ function within and outside the abdominal cavity it remains difficult to compare the literature data because the measurement methods and definitions used are not uniform. Provocative data have been published regarding the interactions between the abdominal and thoracic compartments especially in patients with capillary leak and fluid overload; most of this data raises even more questions than it gives answers and may therefore strengthen the nonbelievers who consider IAP, IAH and ACS as epiphenomena in critically ill patients. Unless the international scientific community does not come forward with clear-cut definitions we will keep comparing 'apples with oranges.'

SUMMARY

It is time to pay attention to intra-abdominal pressure in the critically ill. It is also time for standardized IAP measurement methods, good consensus definitions and randomized interventional studies.

Is Pneumoperitoneum Harmful During Intra-Abdominal Hemorrhage in Rats?

BACKGROUND

Laparoscopic surgical interventions are being used in trauma patients for diagnostic and therapeutic purposes, but there are limited studies on this subject. The effect of pneumoperitoneum during intra-abdominal hemorrhage has not been elucidated. The aim of this study was to investigate the hemodynamic, respiratory, and renal effects of pneumoperitoneum in the splenic injury/ hemorrhagic shock model in rats.

MATERIAL AND METHODS

In this study, 80 anesthetized Wistar male rats (294.5 +/- 31.2 g) were randomized into 2 main groups: nontraumatized (group A) and traumatized (group B). After initial preparation and monitoring, each group was divided according to the degree of pneumoperitoneum. The nontraumatized subgroups were A1, sham-operated; A2, 4-8 mm Hg; A3, 9-13 mm Hg; and A4, 14-18 mm Hg. The traumatized subgroups were B1, splenic injury without pneumoperitoneum; B2, B3, and B4, splenic injury with pneumoperitoneum at 4-8 mm Hg, 9-13 mm Hg, and 14-18 mm Hg, respectively. Mean arterial pressure, heart rate, and respiratory rate were monitored continuously. Blood samples were obtained for hemoglobin, hematocrit, arterial blood gases, and biochemical analyses. Twenty-four hour urine output was collected.

RESULTS

In group B4, pH, pCO2, and HCO3 levels were lower than in all other groups, while pCO2 and base deficit levels were significantly higher (P < 0.05). Both blood and urine analysis results showed that 24-hour urine output and the glomerular filtration rate of groups A4 and B4 were significantly lower (P < 0.05), while urinary osmolarity and fractional sodium excretion levels were significantly higher (P < 0.05).

CONCLUSION

High-pressure pneumoperitoneum in splenically traumatized rats amplifies acidosis, decreases urine output, decreases glomerular filtration rate, and increases urinary osmolarity and fractional sodium excretion significantly.

Influence of different pneumoperitoneal pressures on tumor cell distribution in rats

BACKGROUND

The effect of different pneumoperitoneal pressures on tumor cell distribution was investigated.

METHODS

Donryu rats were allocated to receive carbon dioxide pneumoperitoneum at 5, 10, or 15 mmHg for 60 min or to serve as a control. During the procedure, each rat was inoculated with radiolabeled ascites hepatoma cells via the portal vein (experiment 1) or femoral vein (experiment 2). In both experiments, the rats were killed 30, 60, 90, or 120 min after tumor cell inoculation, and the liver and lungs were extirpated for radioactivity count (n = 5 or 6 for each time point in each group).

RESULTS

In experiment 1, the percentage of injected dose (% ID) for the liver was greater than for the other three groups 120 min after tumor cell inoculation. There were no significant differences in the %IDs of the lungs at any time point among the groups. In experiment 2, there were no significant differences in the %IDs of the liver and lungs at any time point among the groups.

CONCLUSIONS

These results suggest that an elevated insufflation pressure facilitates the location of intraportally injected tumor cells in the liver, and that pulmonary location of the tumor cells may not depend on insufflation pressures in this animal model.

Cirrhosis is not a contraindication to laparoscopic surgery

BACKGROUND

Cirrhosis of the liver contributes significantly to morbidity and mortality in abdominal surgery. The proven benefits of laparoscopy seem especially applicable to patients with this complex disease. This study evaluates the safety and efficacy of laparoscopic procedures in a series of consecutively treated patients with biopsy-proven cirrhosis.

METHODS

The medical records of all patients with biopsy-proven cirrhosis undergoing laparoscopic surgery at the authors' medical center between January 2000 and December 2003 were retrospectively reviewed.

RESULTS

A total of 50 patients (27 men and 23 women) underwent 52 laparoscopic procedures. Among these 50 patients were 39 patients with Child-Pugh classification A cirrhosis, 10 with classification B, and 1 with classification C, who underwent a variety of laparoscopic procedures including cholecystectomy (n = 22), splenectomy (n = 18), colectomy (n = 4), diagnostic laparoscopy (n = 3), ventral hernia repair (n = 1), Nissen fundoplication (n = 1), Heller myotomy (n = 1), Roux-en-Y gastric bypass (n = 1), and radical nephrectomy (n = 1). There were two conversions (4%) to an open procedure. The mean operative time was 155 min. Estimated blood loss averaged 124 ml for all procedures, and 20 patients (40%) required perioperative transfusion of blood products. One patient required a single blood transfusion postoperatively because of anemia. No one experienced hepatic decompensation. Overall morbidity was 16%. There were no deaths. The mean length of hospitalization was 3 days.

CONCLUSIONS

Although technically challenging because portal hypertension, varices, and thrombocytopenia frequently coexist, basic and advanced laparoscopic procedures are safe for patients with mild to moderate cirrhosis of the liver.

Cardiovascular effects of insufflation of the abdomen with carbon dioxide in standing horses sedated with detomidine

OBJECTIVE

To determine the cardiovascular effects of 60 minutes of abdominal insufflation with CO2 to an intra-abdominal pressure of 15 mm Hg in standing horses receiving a constant rate infusion of detomidine.

ANIMALS

5 horses.

PROCEDURE

Horses were randomly allocated into treatment or control groups. A washout period of a minimum of 7 days separated the 2 experimental periods of the crossover study. Catheters were placed into the right atrium, pulmonary artery, jugular vein, and right transverse facial artery after lidocaine infiltration. All horses were sedated with detomidine (8.54 microg/kg/h, i.v.). Horses in the treatment group received abdominal insufflation with CO2 via a laparoscopic cannula to a final and constant intra-abdominal pressure of 15 mm Hg for 60 minutes. Systemic arterial pressure, right atrial pressure, heart rate, cardiac output, core body temperature, and the pH and gas tensions of arterial and mixed venous blood were obtained. Cardiac index and systemic vascular resistance were calculated. Data were collected in 3 stages: preinsufflation (-10 and -5 minutes), insufflation (0, 15, 30, 45, and 60 minutes), and postinsufflation (70 and 80 minutes). The quality of sedation and level of analgesia were determined.

RESULTS

The PaO2 of horses in the treatment group was significantly higher after 60 minutes of pneumoperitoneum than in the control group. Core body temperature decreased significantly from baseline in both groups.

CONCLUSIONS AND CLINICAL RELEVANCE

A 60-minute period of abdominal insufflation to an intra-abdominal pressure of 15 mm Hg did not induce significant cardiovascular abnormalities in healthy horses.