Hemodynamic consequences of high- and low-pressure capnoperitoneum during laparoscopic cholecystectomy

Background: Peritoneal insufflation to 15 mmHg diminishes venous return and reduces cardiac output. Such changes may be dangerous in patients with a poor cardiac reserve. The aim of this study was to investigate the hemodynamic effects of high (15 mmHg) and low (7 mmHg) intraabdominal pressure during laparoscopic cholestectomy (LC) Methods: Twenty patients were randomized to either high- or low-pressure capnoperitoneum. Anesthesia was standardized, and the end-tidal CO₂ was maintained at 4.5 kPa. Arterial blood pressure was measured invasively. Heart rate, stroke volume, and cardiac output were measured by transesophageal doppler. Results: There were 10 patients in each group. In the high-pressure group, heart rate (HR) and mean arterial blood pressure (MABP) increased during insufflation. Stroke volume (SV) and cardiac output were depressed by a maximum of 26% and 28% (SV 0.1 > p > 0.05, cardiac output p > 0.1). In the low-pressure group, insufflation produced a rise in MABP and a peak rise in both stroke volume and cardiac output of 10% and 28%, respectively (p < 0.05). Conclusions: Low-pressure pneumoperitoneum is feasible for LC and minimizes the adverse hemodynamic effects of peritoneal insufflation. Received: 23 May 1997/Accepted: 11 March 1998     

Laparoscopic cholecystectomy and time-course changes in renal function

Background: Recently, the retraction method has been used to reduce intraabdominal pressure (IAP) during laparoscopic surgery. The purpose of this study was to determine the serial changes in renal function during laparoscopic cholecystectomy (LC) using the retraction method. Methods: Urine output, effective renal plasma flow (ERPF), and glomerular filtration rate (GFR) were measured serially in seven patients who underwent LC with 12 mmHg pneumoperitoneum (High-IAP group) and five who underwent LC using the retraction method with 4 mmHg pneumoperitoneum (Low-IAP group). Results: Urine output, ERPF, and GFR were decreased during pneumoperitoneum in the High-IAP group, whereas no significant changes in any of these parameters were observed in the Low-IAP group. Conclusions: Our findings demonstrate that reduction of IAP to 4 mmHg using the retraction method prevents the transient renal dysfunction caused by prolonged 12 mmHg pneumoperitoneum during LC, suggesting that the retraction method reduces the risk of perioperative renal dysfunction during laparoscopic surgery. Received: 26 March 1996/Accepted: 27 July 1996     

Portal venous flow during CO2 pneumoperitoneum in the rat

Backround: CO₂ gas insufflation is routinely used to extend the abdominal wall. The resulting pneumoperitoneum has a number of local and systemic effects on the organism. Portal blood flow, which plays an important role in hepatic function and cell-conveyed immune response, is one of the affected parameters. Methods: An established animal model (rat) of laparoscopic surgery was modified by implanting a perivascular flow probe. Hemodynamics in the portal vein were then measured during increasing intraabdominal pressure generated by carbon dioxide insufflation. Results: Using this technique, an adequate flowmetry of the portal vein was achieved in all animals. The creation of a CO₂ pneumoperitoneum with increasing intraabdominal pressure led to a linear decrease in portal venous flow. Conclusions: Elevated intraabdominal pressure caused by carbon dioxide insufflation may compromise hepatic function and cell-conveyed immune response during laparoscopic surgery. Received: 28 January 1998/Accepted: 22 June 1998     

Laparoscopic insufflation of the abdomen reduces portal venous flow

Background: The adverse effects of sustained elevated intraperitoneal pressure (IPP) on cardiovascular, pulmonary and renal systems have been well documented by several reported experimental and clinical studies. Alteration in the splanchnic circulation has also been reported in animal experiments, but details of the exact hemodynamic changes in the flow to solid intraabdominal organs brought on by a raised intraperitoneal pressure in the human are not available. The aim of the present study was to estimate effect of increased IPP on the portal venous flow, using duplex Doppler ultrasonography in patients undergoing laparoscopic cholecystectomy. Methods: The studies were performed using the SSD 2000 Multiview Ultrasound Scanner and the UST 5536 7.0-MHz laparoscopic transducer probe. Details of the measurements were standardized in according to preset protocol. Statistical evaluation of the data was conducted by the two-way analysis of variance (ANOVA). Results: The flow measurement data have demonstrated a significant (p < 0.001) decrease in the portal flow with increase in the intraperitoneal pressure. The mean portal flow fell from 990 ± 100 ml/min to 568 ± 81 ml/min (−37%) at an IPP of 7.0 mmHg and to 440 ± 56 mmHg (−53%) when the IPP reached 14 mmHg. Conclusions: The increased intraperitoneal pressure necessary to perform laparoscopic operations reduces substantially the portal venous flow. The extent of the volume flow reduction is related to the level of intraperitoneal pressure. This reduction of flow may depress the hepatic reticular endothelial function (possibly enhancing tumor cell spread). In contrast, the reduced portal flow may enhance cryo-ablative effect during laparoscopic cryosurgery for metastatic liver disease by diminishing the heat sink effect. These findings suggest the need for a selective policy, low pressure or gas-less techniques to positive-pressure interventions, during laparoscopic surgery in accordance with the disease and the therapeutic intent. Received: 19 March 1996/Accepted: 4 July 1997     

Alterations in hepatic function during laparoscopic surgery

Background: Very few studies have been done on the consequences of pneumoperitoneum on hepatic function. At present, there is no consensus on the physiopathological hepatic implications of pneumoperitoneum. The purpose of this clinical study was to evaluate the effects of pneumoperitoneum on hepatic function in 52 patients treated with laparoscopic procedures. Methods: Thirty-two laparoscopic cholecystectomies and 20 nonhepatobiliary laparoscopic procedures were performed in 52 patients (12 men and 40 women) with a mean age of 44 years (range, 15–74). All patients had normal values on preoperative liver function tests. The anesthesiologic protocol was uniform, with drugs at low hepatic metabolism. The 32 cholecystectomies were randomized into 22 performed with pneumoperitoneum at 14 mmHg and 10 performed at 10 mmHg. All nonhepatobiliary laparoscopic procedures were performed with a pneumoperitoneum of 14 mmHg. The postoperative serologic levels of AST, ALT, bilirubin, and prothrombin time were measured at 6, 24, 48, and 72 h. The serologic changes were related to the procedure, the duration, and the level of pneumoperitoneum. Results: Mortality and morbidity were nil. All 52 patients had a postoperative increase in AST, ALT, bilirubin, and lengthening in prothrombin time. Slow return to normality occurred 48 or 72 h after operation. The increase of AST and ALT was statistically significant and correlated both to the level (10 versus 14 mmHg) and the duration of pneumoperitoneum. Conclusions: The duration and level of intraabdominal pressure are responsible for changes of hepatic function during laparoscopic procedures. Although no symptom appears in patients with normal hepatic function, patients with severe hepatic failure should probably not be subjected to prolonged laparoscopic procedures. Received: 23 May 1997/Accepted: 28 October 1997     

Hepatic and portal vein blood flow during carbon dioxide pneumoperitoneum for laparoscopic hepatectomy

Background: Laparoscopy under carbon dioxide (CO₂) pneumoperitoneum has many advantages. However, the risks of CO₂ pneumoperitoneum during laparoscopic hepatectomy (LH) have not been defined. Methods: The hemodynamics of the hepatic vein were examined during CO₂ pneumoperitoneum both pre- and posthepatectomy in eight pigs. Portal blood flow was measured with Doppler ultrasound during laparoscopic cholecystectomy in 10 human patients. Results: Experimentally, elevated intraabdominal pressure (IAP) with CO₂ insufflation produced significant increases in CO₂ partial pressure and echogenicity of the hepatic vein in the posthepatectomy group. Clinically, elevated IAP caused significant narrowing of the portal vein and significant decreases in portal blood velocity. The mean portal flow was significantly decreased with elevation of IAP >10 mmHg. Conclusions: LH with CO₂ pneumoperitoneum may lead to embolism caused by CO₂ bubbling through the hepatic vein. Elevated IAP may cause a decrease in hepatic blood flow and induce severe liver damage, especially in patients with poor liver function. Gasless laparoscopy using abdominal wall lifting should be employed in LH to avoid the risks of CO₂ embolism and liver damage. Received: 28 March 1997/Accepted: 12 September 1997     

Evaluation of mechanism of increased intracranial pressure with insufflation

Background: Previous studies have documented an increase in intracranial pressure with abdominal insufflation, but the mechanism has not been explained. Methods: Nine 30–35-kg domestic pigs underwent carbon dioxide insufflation at 1.5 l/min. Intracranial pressure (ICP), lumbar spinal pressure (LP), central venous pressure (CVP), inferior vena cava pressure (IVCP), heart rate, systemic arterial blood pressure, pulmonary arterial pressure, cardiac output, heart rate, respiratory rate, temperature, and end-tidal CO₂ were continuously measured. Mechanical ventilation was used to maintain a constant pCO₂. Measurements were recorded at 0, 5, 10, and 15 mmHg of abdominal pressure with animals in supine, Trendelenburg (T), and reverse Trendelenburg (RT) positions. Prior to recording measurements, the animals were allowed to stabilize for 40 min after each increase in abdominal pressure and for 20 min after each position change. Results: The animals showed a significant increase in ICP (mmHg) with each 5-mmHg increase in abdominal pressure (0 mmHg: 14 ± 1.7; 5 mmHg: 19.8 ± 2.3, p < 0.001; 10 mmHg: 24.8 ± 2.5, p < 0.001; 15 mmHg: 29.8 ± 4.7, p < 0.01). The ICP at 15 mmHg abdominal pressure increased further in the T position (39 ± 4, p < 0.01). Insufflating in the RT position did not significantly reduce the increase in ICP. The IVCP (mmHg) increased with increased abdominal pressure (0 mmHg: 11.5 ± 6.2, 15 mmHg: 22.1 ± 3.5, p < 0.01). This increase correlated with the increase in ICP and LP (r of mean pressures ≥0.95). There was no significant change in CVP. Conclusions: This study suggests that care may be needed with laparoscopy in patients at risk for increased ICP due to head injury or a space occupying lesion. The mechanism of increased ICP associated with insufflation is most likely impaired venous drainage of the lumbar venous plexus at increased intraabdominal pressure. Further studies of cerebral spinal fluid movement during insufflation are currently underway to confirm this hypothesis. Received: 28 March 1997/Accepted: 5 August 1997     

Intracranial pressure

Background: The effects of pneumoperitoneum on intracranial pressure (ICP) have received relatively little attention. This study was undertaken to investigate the changes in ICP occurring as a result of increased intraabdominal pressure (IAP) and positioning in animals with normal and elevated ICP. Method: Five pigs (average weight 60 lb) were studied. A subarachnoid screw was placed for ICP monitoring. End tidal CO₂ was monitored. Ventilation was performed to keep PCO₂ between 30 and 50 mmHg. Measurements of arterial blood gases, mean arterial blood pressure, and ICP were recorded at four different levels of intraabdominal pressure (IAP 0, 8, 16, and 24 mmHg), both in the supine and Trendelenburg positions. A Foley catheter was introduced into the subarachnoid space to elevate the intracranial pressure, and the same measurements were performed. Results: There was a significant and linear increase in ICP with increased IAP and Trendelenburg position. The combination of increased IAP of 16 mmHg and Trendelenburg position increased ICP 150% over control levels. Conclusions: Patient positioning and level of IAP should be taken into consideration when performing laparoscopy on patients with head trauma, cerebral aneurysms, and other conditions associated with increased ICP. Received: 19 March 1996/Accepted: 24 May 1996     

The adverse hemodynamic effects of anesthesia, head-up tilt, and carbon dioxide pneumoperitoneum during laparoscopic cholecystectomy

Background: The increased intra-abdominal pressure during pneumoperitoneum, together with the head-up tilt used in upper abdominal laparoscopies, would be expected to decrease venous return to the heart. The goal of our study was to determine whether laparoscopy impairs cardiac performance when preventive measures to improve venous return are taken, and to analyze the effects of positioning, anesthesia, and increased intra-abdominal pressure. Methods: Using invasive monitoring, hemodynamic changes were investigated in 15 ASA class I or II patients under isoflurane–fentanyl anesthesia during laparoscopic cholecystectomy. Before laparoscopy, the patients received an intravenous (IV) infusion of colloid solution if cardiac filling pressures were low, and their legs were wrapped from toes to groin with elastic bandages. Measurements were taken while the patients were awake in the supine (baseline) and head-up tilt (15–20°) positions, and after the induction of anesthesia in the same positions. Measurements were repeated at regular intervals during laparoscopy (intra-abdominal pressure at 13–16 mmHg), after deflation of the gas, and in the recovery room. Results: With the passive head-up tilt in awake and anesthetized patients, the cardiac index (CI), stroke index (SI), central venous pressure (CVP), and pulmonary capillary wedge pressure (PCWP) decreased, and systemic vascular resistance increased. With the patient under anesthesia, SI decreased, but CI did not change significantly as a result of the compensatory increase in heart rate. Carbon dioxide (CO₂) insufflation at the start of laparoscopy produced increases in CVP and PCWP as well as mean systemic and mean pulmonary arterial pressures without changes in CI or SI. Toward the end of the laparoscopy, CI decreased by 15%. The hemodynamic values returned to nearly prelaparoscopic levels after deflation of the gas, and CI was elevated during the recovery period, whereas systemic vascular resistance was decreased in comparison with the baseline. Conclusions: By correcting relative dehydration and preventing the pooling of blood, CI decreased less than 20% during pneumoperitoneum as compared with the baseline awake level. The head-up positioning accounts for many of the adverse effects in hemodynamics during laparoscopic cholecystectomy. Received: 6 November 1998/Accepted: 8 July 1999     

Effects of carbon dioxide vs helium pneumoperitoneum on hepatic blood flow

Background: Elevated intraabdominal pressure due to gas insufflation for laparoscopic surgery may result in regional blood flow changes. Impairments of hepatic, splanchnic, and renal blood flow during peritoneal insufflation have been reported. Therefore we set out to investigate the effects of peritoneal insufflation with helium (He) and carbon dioxide (CO₂) on hepatic blood flow in a porcine model. Methods: Twelve pigs were anesthetized and mechanically ventilated with a fixed tidal volume after the stabilization period. Peritoneal cavity was insufflated with CO₂ (n= 6) or He (n= 6) to a maximum intraabdominal pressure of 15 mmHg. Hemodynamic parameters, gas exchange, and oxygen content were studied at baseline, 90 mm and 150 min after pneumoperitoneum, and 30 min after desufflation. Determination of hepatic blood flow with indocyanine green was made at all measured points by a one-compartment method using hepatic vein catheterization. Results: A similar decrease in cardiac output was observed during insufflation with both gases. Hepatic vein oxygen content decreased with respect to the baseline during He pneumoperitoneum (p < 0.05), but it did not change during CO₂ insufflation. Hepatic blood flow was significantly reduced in both the He and CO₂ pneumoperitoneums at 90 min following insufflation (63% and 24% decrease with respect to the baseline; p < 0.001 and p < 0.05, respectively) being this decrease marker in the He group (p= 0.02). Conclusions: These findings suggest that helium intraperitoneal insufflation results in a greater impairment on hepatic blood flow than CO₂ insufflation. Received: 27 March 1996/Accepted: 19 January 1997     

Emergency laparoscopy for abdominal stab wounds

Background: Management strategies for abdominal stab wounds (ASW) in initially asymptomatic patients range from mandatory explorative laparotomy (EL) to conservative approaches with observation alone. Emergency diagnostic laparoscopy (DL) may play a potential role between these two extremes—hence lowering the rate of unnecessary laparotomies and keeping the rate of missed injuries to a minimum. Patients and Methods: At our institution mandatory EL was carried out in every patient with ASW until 1992. In a retrospective study the charts of 43 patients with ASW were reviewed in terms of initial diagnostic procedures, intraabdominal injuries, and course and length of hospital stay. Between 5/1993 and 4/1995 DL was performed in a prospective study in 15 patients with suspected peritoneal penetration (PP) after ASW according to a standardized diagnostic and therapeutic algorithm. Results: In 17 patients (40%) EL showed no PP; 15 (35%) had significant intraabdominal injuries, while 11 patients with PP didn't have lacerations of intraabdominal organs, resulting in an overall rate of nontherapeutic laparotomy of 65%. Mortality was 6% (n= 3), average hospital stay 8 days. Primary DL could exclude PP in 10 out of 15 patients (66%). The remaining five patients (33%) showed PP: In two patients with ASW to the right upper quadrant, intraabdominal injuries could be excluded by DL, and in one patient a low-grade liver injury was treated laparoscopically, thus avoiding laparotomy in a total of 87% (n= 13). In two patients with PP laparoscopy was converted to laparotomy: no pathological finding in one case, splenectomy for spleen laceration in the second patient, resulting in a rate of nontherapeutic laparotomies of 7%. All patients in this series had an uneventful course; average hospital stay was 2.4 days. Conclusions: DL offers an important diagnostic tool in excluding peritoneal penetration in ASW, hence lowering the rate of unnecessary laparotomies. Given experience and skills, laparoscopy may be used therapeutically in selected cases of ASW. Received: 24 February 1997/Accepted: 10 August 1997     

Prolonged pneumoperitoneum at 15 mmHg causes lactic acidosis

Background: Acute increases in intraabdominal pressure (IAP) induce systemic and regional circulatory changes. Besides, mechanical compression on the capillary beds may decrease oxygen availability to the tissues. The purpose of this clinical study was to analyze the effects of increased IAP on acid-base disturbances and plasma lactate levels during prolonged carbon dioxide pneumoperitoneum. Methods: Twenty-eight patients undergoing laparoscopic sigmoidectomy were included in this study. Fourteen of them (group A) had IAP of 15 ± 1 mmHg while the remaining 14 (group B) had IAP of 10 ± 1 mmHg. The control group included six patients undergoing conventional sigmoidectomy. Results: A progressive significant increase in PaCO₂ was observed in the laparoscopic groups (p < 0.01). Plasma lactate levels in group A significantly increased 90 min after insufflation (p < 0.05) and reached the highest value 1 h after deflation (9.9 ± 1 vs 31.9 ± 2.5 mg/dl, p < 0.005). Simultaneously, arterial pH decreased in all groups; however, at 1 h after surgery, it was significantly lower (p= 0.02) in group A. There was a significant correlation between acid concentration due to lactate and lactate concentration (GA: R ²= 0.717, p= 0.03; GB: R ²= 0.879, p= 0.006 and GC: R ²= 0.853, p= 0.008). Conclusion: High IAP causes lactic acidic accumulation in patients undergoing prolonged laparoscopic procedures. Received: 1 April 1996/Accepted: 19 November 1996     

Lack of neurohumoral response to pneumoperitoneum for laparoscopic cholecystectomy

Background: Pneumoperitoneum (PP) for laparoscopic surgery induces prompt changes in circulatory parameters. The rapid onset of these changes suggests a reflex origin, and the present study was undertaken to evaluate whether release of vasopressor substances could be responsible for these alterations. The influence of two different anesthesia techniques was also evaluated. Methods: American Society of Anesthesiologists (ASA) class I patients, scheduled for laparoscopic cholecystectomy, were investigated. The first group (n= 10) was anesthetized intravenously. The second group (n= 6) had inhalation anesthesia. Plasma vasopressin, catecholamines, and plasma renin activity were investigated as neurohumoral vasopressor markers of circulatory stress. The general stress response to surgery was assessed by analysis of plasma cortisol. Results: Induction of pneumoperitoneum caused no apparent activation of vasopressor substances, although several hemodynamic parameters responded promptly. Conclusion: The hemodynamic alterations, seen at the establishment of PP during stable anesthesia, cannot be explained by elevation of vasopressor substances in circulating blood. Received: 7 April 1997/Accepted: 3 December 1997     

Effect of carbon dioxide pneumoperitoneum on bacteremia and severity of peritonitis in an experimental model

Background: Laparoscopy is increasingly used in conditions complicated by peritonitis. A theoretical concern is that carbon dioxide pneumoperitoneum may increase bacteremia. Method: In 60 rats peritonitis was induced by cecostomy. Animals were randomly allocated to pneumoperitoneum (PP) and control groups. Blood cultures and intraabdominal swabs were assessed. A peritonitis severity score (PSS) was computed based on histology from peritoneal biopsy. Results: One hour after cecostomy neither in abdominal swabs nor in blood samples bacteria were reproduced in PP and control groups. Three hours after cecostomy the frequency of positive blood cultures was 80% and 20% in PP and control groups, respectively (p < 0.0001). Six hours after cecostomy the frequency of positive blood cultures was 100% in each group (p > 0.05). One hour after cecostomy the mean peritoneal severity score was significantly higher in the PP group than in the control group, but there was not any significant difference between groups 3 and 6 h after cecostomy. The mean peritoneal severity scores were found to be significantly increased with time when the PP groups compared with each other. Conclusion: In rats, pneumoperitoneum can't cause a more severe peritonitis but it does induce an increase in the rate of bacteremia within the early 6-h period of peritonitis. Received: 14 April 1997/Received: 18 September 1997     

Laparoscopic Collis gastroplasty and Nissen fundoplication

Background: The short esophagus increases the difficulty and limits the effectiveness of laparoscopic Nissen fundoplication. In our experience, ∼20–25% of esophagi judged by preoperative criteria to be foreshortened will, after dissection, be insufficiently long to allow 2 cm of esophagus to reside below the diaphragm without inferior distraction (i.e., tension free). Collis gastroplasty combined with Nissen fundoplication has become the standard approach for the creation of an intraabdominal neoesophagus and fundic wrap. Methods: After developing methods of performing totally laparoscopic stapled gastroplasty in the cadaver lab in 1994, we started applying the technique clinically in 1996. We performed 220 laparoscopic antireflux procedures between January 1996 and July 1997. Of these 220 patients, 26% were suspected to have esophageal foreshortening based on preoperative barium studies and/or endoscopy. Results: After hiatal dissection, nine patients, or 16% of those suspected to have esophageal foreshortening and 4% of the entire population, required the laparoscopic Collis-Nissen procedure. There was symptomatic improvement in all patients as assessed by patient-initiated symptom scores. Conclusions: The management of patients with esophageal foreshortening is a complex problem. We believe that our technique of laparoscopic Collis-Nissen provides an effective means of achieving intraabdominal placement of the fundic wrap while maintaining the benefits of a minimally invasive approach. Received: 8 September 1997/Accepted: 17 December 1997     

Prevalence of gastroesophageal reflux after laparoscopic Heller myotomy

Background: There is still some controversy over the need for antireflux procedures with Heller myotomy in the treatment of achalasia. This study was undertaken in an effort to clarify this question. Methods: To determine whether Heller myotomy alone would cause significant gastroesophageal reflux (GER), we studied 16 patients who had undergone laparoscopic Heller myotomy without concomitant antireflux procedures. Patients were asked to return for esophageal manometry and 24-h pH studies after giving informed consent for the Institutional Review Board (IRB)-approved study at a median follow-up time of 8.3 months (range, 3–51). Results are expressed as the mean ± SEM. Results: Fourteen of the 16 patients reported good to excellent relief of dysphagia after myotomy. They were subsequently studied with a 24-h pH probe and esophageal manometry. These 14 patients had a significant fall in lower esophageal sphincter (LES) pressure from 41.4 ± 4.2 mmHg to 14.2 ± 1.3 mmHg, after the myotomy (p < 0.01, Student's t-test). The two patients who reported more dysphagia postoperatively had LES pressures of 20 and 25 mmHg, respectively. Two of 14 patients had DeMeester scores of >22 (scores = 61.8, 29.4), while only one patient had a pathologic total time of reflux (percent time of reflux, 8%). The mean percent time of reflux in the other 13 patients was 1.9 ± 0.6% (range, 0.1–4%), and the mean DeMeester score was 11.7 ± 4.6 (range, 0.48–19.7). Conclusions: Laparoscopic Heller myotomy is effective for the relief of dysphagia in achalasia if the myotomy lowers the LES pressure to <17 mmHg. If performed without dissection of the entire esophagus, the laparoscopic Heller myotomy does not create significant GER in the postoperative period. Clearance of acid refluxate from the aperistaltic esophagus is an important component of the pathologic gastroesophageal reflux disease (GERD) seen after Heller myotomy for achalasia. Furthermore, GERD symptoms do not correlate with objective measurement of GE reflux in patients with achalasia. Objective measurement of GERD with 24 h pH probes may be indicated to identify those patients with pathologic acid reflux who need additional medical treatment. Received: 12 May 1998/Accepted: 15 December 1998     

A simple scoring system to reduce intraabdominal septic complications after laparoscopic appendectomy

Background: The development of intraabdominal abscess (IAA) following laparoscopic appendectomy (LA) is associated with significant morbidity. The aim of the present study was to validate an IAA risk score constructed from a previous review of 156 consecutive LA. Methods: The score was tested in 250 subsequent consecutive LA and in patients with a positive risk score. Broad-spectrum antibiotics were administered in order to avoid IAA. Results: Factors related to IAA included clinically complicated appendicitis, leucocytosis >15,000/μl, a difference of >1°C between axillary and rectal temperature, intraoperative findings such as (gangrenes and perforation), and intraoperative perforation of the appendix. In this series, broad-spectrum antibiotic therapy in patients with a positive IAA risk score reduced the incidence of IAA from 7.05% to 1.60%. Conclusion: This policy of identifying high-risk patient via the scoring system and instituting subsequent antibiotic therapy in patients at risk reduces the incidence of IAA following LA. Received: 20 October 1999/Accepted: 7 March 2000/Online publication: 7 September 2000     

Pathophysiological and clinical aspects of the CO2 pneumoperitoneum (CO2-PP)

Experimental studies demonstrated a severe cardiac load of the CO₂ pneumoperitoneum caused by an accelerated after- and a decreased preload. Patients displaying cardiovascular risks are therefore often rejected from laparoscopic surgery. Hence, the pathophysiological changes and the intraoperative risk of the CO₂ pneumoperitoneum in high-risk cardiopulmonary patients (NYHA II–III, n= 15) undergoing laparoscopic cholecystectomy are described. The changes in cardiac after- and preload seem to be due to the elevated intraabdominal pressure rather than transperitoneally resorbed CO₂ and are reversible by desufflation. In one patient conversion to open operation had to be performed because of a severe drop in cardiac output and right ventricle ejection fraction. Mixed oxygen saturation was predicting intraoperative worsening in this case. The described pathophysiological changes may seem to be well tolerated even in high-risk cardiac patients. Monitoring of hemodynamics should include an arterial catheter line and blood gas analyses. Pharmacologic interventions or pressureless laparoscopic procedures might not be necessary as long as laparoscopic cholecystectomy is performed. Received: 13 December 1996/Accepted: 8 January 1997     

Laparoscopic cholecystectomy and interventional endoscopy for gallstone complications during pregnancy

Background: Symptomatic or complicated gallstone disease is the most common reason for nongynecological operations during pregnancy. Gallstones are present in 12% of all pregnancies, and more than one-third of patients fail medical treatment and therefore require surgical endoscopy or laparoscopy. Gallstone pancreatitis and jaundice during pregnancy is associated with a high recurrence rate, exposing both fetus and mother to an increased risk of morbidity and mortality. Methods: During a 4-year period, all pregnant patients (n= 37) with symptomatic or complicated gallstone disease were studied prospectively at the Landeskrankenhaus in Salzburg, Austria. Five patients had an endoscopic retrograde cholangiopancreatogram (ERCP) for biliary pancreatitis or jaundice; two of these underwent subsequent laparoscopic cholecystectomy. Another seven patients required laparoscopic cholecystectomy for severe pain or cholecystitis; all were in their 13th–32nd gestational week. Access was established by Veress needle in all cases. Insufflation pressure was 8–10 mmHg, and mean operative time was 62 min. Results: All patients delivered full-term, healthy babies. There were no postendoscopic or postoperative complications. All patients enjoyed full relief from their symptoms; there were no recurrences of pancreatitis or jaundice. Conclusions: The combination of ERCP and laparoscopic cholecystectomy offers a safe and effective option for the definitive treatment of complicated gallstone disease and intractable pain during pregnancy, and there is sufficient access for the combined treatment to be employed. Received: 7 September 1998/Accepted: 2 June 1999     

Influence of acute hemorrhage and pneumoperitoneum on hemodynamic and respiratory parameters

Background: We examined the questions of whether resuscitated (compensated) acute hemorrhage enhances the negative effects of carbopneumoperitoneum on hemodynamic and respiratory parameters and whether pneumoperitoneum with helium has any advantages under these circumstances. Our investigation focused on the influence of acute hemorrhage with different gases on the cardiovascular and respiratory system as well as on hepatic and renal blood flow in a porcine model. Methods: Cardiac and hemodynamic function were monitored via implantation of catheters in pulmonary artery, femoral vein, and artery. Renal and hepatic blood flow were recorded using a transonic volume flow meter placed at the renal and hepatic artery and portal vein. Twelve animals were randomly assigned to one insufflation gas (carbon dioxide [CO₂] or helium [He]). Following baseline recordings, acute hemorrhage (20 ml/kg) was induced by continuous bleeding over 30 min. Animals then received a colloidal solution (20 ml/kg 6% hydroxyethylstarch solution) over 30 min. Pneumoperitoneum of 12 mmHg was established, and all parameters were measured after 30 min of adaptation. The major endpoints of the study were cardiac output (CO), arterial pressure (MAP), systemic vascular resistance (SVR), and central venous pressure (CVP), as well as blood flow in hepatic and renal artery and portal vein. Results: While CO and hemodynamic parameter as well as hepatic and renal blood flow were markedly reduced after hemorrhage, they returned nearly to their previous levels after resuscitation. Pneumoperitoneum with 12 mmHg did not further depress the cardiovascular system or reduce hepatic and renal blood flow. Pneumoperitoneum did not alter hepatic or renal blood flow. Pneumoperitoneum with helium did not substantially change the reaction of the cardiovascular system after resuscitated hemorrhage. Conclusions: If hemorrhage is compensated by proper resuscitation and hypovolemia is avoided, laparoscopic surgery with pneumoperitoneum of 12 mmHg appears to be not harmful. Using helium as the insufflating gas had no clear advantage over the carbon dioxide model. Received: 30 July 1997/Accepted: 24 October 1997