***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Background Because of absorbed carbon dioxide ( CO2 ) and elevated intraabdominal pressure ( IAP ) , CO2 pneumoperitoneum ( CO2PP ) has potentially harmful intraoperative circulatory and ventilatory effects . Although not clinical ly 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 CO2PP-related adverse effects by comparing ASA 3 and 4 patients who underwent laparoscopic cholecystectomy ( LC )  with or without CO2PP . Methods A total of 20 successive ASA 3 and 4 patients who underwent LC were r and omized into CO2PP ( 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 CO2PP 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 CO2PP 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 CO2 pneumoperitoneum . For high-risk patients , preoperative preparation and active perioperative monitoring are essential for safe anesthesia for LC with or without CO2PP We have compared , in a r and omized study , conventional carbon dioxide pneumoperitoneum with abdominal wall lift in 25 patients undergoing laparoscopic cholecystectomy .  Intra-abdominal pressure ( IAP ) ( 11 ( SD 2 ) mm Hg vs 2.7 ( 9 ) mm Hg ) ( P < 0.01 ) and total amount of carbon dioxide used ( 40 ( 23 ) litre vs 9 ( 7 ) litre ) ( P < 0.001 ) were significantly less with abdominal wall lift . Pulmonary compliance was significantly greater ( P < 0.01 ) in the abdominal wall lift group throughout operation . During the first 15 min of insufflation , arterial pressures were lower with abdominal wall lift ( P < 0.05 ) . In the conventional pneumoperitoneum group , femoral vein pressure increased ( P < 0.01 ) and remained elevated for 3 h in the recovery room . Postoperative drowsiness was of significantly longer duration in the conventional pneumoperitoneum group than in the abdominal wall lift group ( 98 ( 46 ) min vs 13 ( 34 ) min ) ( P < 0.01 ) . Postoperative nausea and vomiting and right shoulder pain occurred more often in patients with conventional pneumoperitoneum ( P < 0.05 ) . We conclude that the benefits of abdominal wall lift may be attributed to avoiding excessive carbon dioxide and high IAP Abstract Background : Laparoscopic cholecystectomy using low-pressure pneumoperitoneum ( 8 mmHg ) minimizes adverse hemodynamic effects , reduces postoperative pain , and accelerates recovery . Similar cl aims are made for gasless laparoscopy using abdominal wall lifting . The aim of this study was to compare gasless laparoscopic cholecystectomy to low-pressure cholecystectomy with respect to postoperative pain and recovery . Methods : Thirty-six patients were r and omized to low-pressure or gasless laparoscopic cholecystectomy using a subcutaneous lifting system ( Laparotenser ) .  Results : The characteristics of the patients were similar in the two groups . The procedure was completed in all patients in the low-pressure group , but two patients in the gasless group were converted to pneumoperitoneum . There were no significant differences in postoperative pain and analgesic consumption , but patients in the gasless group developed shoulder pain more frequently ( 50 % vs 11 % , p < 0.05 ) . Gasless operation took longer to perform ( 95 vs 72.5 min , p= 0.01 ) . Conclusions : Gasless and low-pressure laparoscopic cholecystectomy were similar with respect to postoperative pain and recovery . The gasless technique provided inferior exposure and the operation took longer , but the technique may still have value in high-risk patients with cardiorespiratory disease We have compared , in a r and omized study in 26 patients , immediate and late postoperative recovery after elective laparoscopic cholecystectomy using the gasless , mechanical abdominal wall lift method with conventional carbon dioxide pneumoperitoneum .  After the gasless method , tracheal extubation was performed significantly earlier than after the conventional method ( P < 0.01 ) . End-tidal carbon dioxide concentrations were significantly higher after pneumoperitoneum for 30 min after operation ( P < 0.01 ) . In the conventional group , deviation in Maddox-Wing recordings from preoperative values remained at a significantly higher level during the 3-h recovery room period ( P < 0.01 ) . There was a positive correlation between the total amount of carbon dioxide used and duration of drowsiness ( r = 0.61 , P < 0.001 ) and the Maddox-Wing deviation ( r = 0.62 , P < 0.001 ) . Postoperative nausea and vomiting , and right shoulder pain occurred less often after the gasless method ( P < 0.05 ) . Late recovery criteria ( ability to drink , void and walk ) in patients in the gasless group were fulfilled approximately 7 h earlier than in those in the pneumoperitoneum group ( P < 0.01 ) . Gasless laparoscopic cholecystectomy result ed in more uneventful and faster immediate and late postoperative recovery than conventional carbon dioxide pneumoperitoneum Although laparoscopic cholecystectomy has rapidly developed in the treatment of gall bladder disease in the absence of controlled clinical trial data its outcome parameters compared with open cholecystectomy remain unclear . A prospect i ve audit of the introduction of laparoscopic cholecystectomy in the west of Scotl and over a two year period was carried out to attempt to assess this new procedure . A total of 45 surgeons in 19 hospitals performing laparoscopic cholecystectomy su bmi tted prospect i ve data from September 1990 - 1992 . A total of 2285 cholecystectomies were audited ( a completed data collection rate of 99 % ) . Laparoscopic cholecystectomy was attempted in 1683 ( 74 % ) patients and completed in 1448 patients ( median conversion rate to the open procedure 17 % ) . The median operation time in the completed laparoscopic cholecystectomy patients was 100 minutes ( range 30 - 330 ) and overall hospital stay three days ( 1 - 33 ) . There were nine deaths ( 0.5 % ) after laparoscopic cholecystectomy although only two were directly attributable to the laparoscopic procedure . In the laparoscopic cholecystectomy group there were 99 complications ( 5.9 % ) , 53 ( 3 % ) of these were major requiring further invasive intervention . Forty patients ( 2.4 % ) required early or delayed laparotomy for major complications such as bleeding or bile duct injuries . There were 11 ( 0.7 % ) bile duct injuries in the laparoscopic cholecystectomy series , five were noted during the initial procedure and six were recognised later result ing from jaundice or bile leaks . Ductal injuries occurred after a median of 20 laparoscopic cholecystectomies . In conclusion laparoscopic cholecystectomy has rapidly replaced open cholecystectomy in the treatment of gall bladder disease . Although the overall death and complication rate associated with laparoscopic cholecystectomy is similar to open cholecystectomy , the bile duct injury rate is higher We have studied the cardiorespiratory changes produced by abdominal wall elevation ( AWE ) or carbon dioxide pneumoperitoneum ( PN ) in 20 women undergoing gynaecological laparoscopy .  Arterial pressure , heart rate , lung/chest complicance and blood-gas tensions were measured 10 min after induction of general anaesthesia ( T0 ) , 10 min after abdominal distension in the supine position ( T1 ) and 10 min after the Trendelenburg position was assumed ( T2 ) . Visual analogue scores for pain were recorded 1 and 6 h after the end of surgery . We found that lung/chest compliance was reduced significantly in group PN at T1 and T2 compared with both T0 and group AWE . Diastolic arterial pressure increased significantly in group PN at T1 and T2 compared with both T0 and group AWE , while it remained unchanged in group AWE . Arterial PCO2 increased significantly only in group PN after pneumoperitoneum , while oxygenation was almost unchanged in both groups . AWE patients had greater abdominal pain 1 h after surgery . Six hours after surgery pain was similar in the two groups . These data indicate that abdominal wall elevation reduced pulmonary compliance less than a pneumoperitoneum in patients undergoing gynaecological laparoscopy OBJECTIVES To analyze sources search ed in Cochrane review s , to determine the proportion of trials included in review s that are indexed in major data bases , and to compare the quality of these trials with those from other sources . METHODS All new systematic review s in the Cochrane Library , Issue1 2001 , that were restricted to r and omized controlled trials ( RCTs ) or quasi- RCTs were selected . The sources search ed in the review s were recorded , and the trials included were checked to see whether they were indexed in four major data bases . Trials not indexed were checked to determine how they could be identified . The quality of trials found in major data bases was compared with those found from other sources . RESULTS The range in the number of data bases search ed per review ranged between one and twenty-seven . The proportion of the trials in the four data bases were Cochrane Controlled Trials Register = 78.5 % , MEDLINE = 68.8 % , Embase = 65.0 % , and Science/Social Sciences Citation Index = 60.7 % . Search ing another twenty-six data bases after Cochrane Controlled Trials Register ( CCTR ) , MEDLINE , and Embase only found 2.4 % additional trials . There was no significant difference between trials found in the CCTR , MEDLINE , and Embase compared with other trials , with respect to adequate allocation concealment or sample size . CONCLUSIONS There was a large variation between review s in the exhaustiveness of the literature search es . CCTR was the single best source of RCTs . Additional data base search ing retrieved only a small percentage of extra trials . Contacting authors and manufacturers to find unpublished trials appeared to be a more effective method of obtaining the additional better quality trials Objective : Carbon dioxide ( CO2 ) pneumoperitoneum has been implicated as a possible factor in early immune preservation in laparoscopic surgery . Although the current analysis was not adequate to clarify this issue , the aim of this study was to compare CO2 insufflation laparoscopic cholecystectomy to gasless abdominal wall lift laparoscopic cholecystectomy with respect to preservation of the immune system . Method : An analysis of the temporal immune responses was performed in 2 similar groups of patients ( n = 50 ) who were divided r and omly into the categories of gas or abdominal wall lift laparoscopic cholecystectomy .  The patients were matched with respect to age , weight , and operation time . The immune parameters ( serum white blood cell count , cortisol , erythrocyte sedimentation rate [ ESR ] , tumor necrosis factor-α[TNF-α ] , interferon-γ[INF-γ ] , interleukin-6 [ IL-6 ] , interleukin-8 [ IL-8 ] ) were assessed at preoperative 24 hours and at postoperative 24 and 72 hours for the 2 groups . During the operation , the levels of cytokines that were cultured in the peritoneal macrophages were also checked . Results : The serum white blood cell count , cortisol , and ESR levels were not statistically different in either of the 2 groups . Further , the serum TNF-α , INF-γ , IL-6 , and IL-8 levels in both groups were not significantly different from each other at preoperative 24 hours , and postoperative 24 and 72 hours . However , an immediate decrease in the cytokine levels at 24 hours after the operation was significant in both groups . The cytokine levels were particularly higher in the cultured peritoneal macrophages than in the serum , but were not statistically different between the 2 groups . Conclusion : Our results showed that the beneficial immune 
    Output:
    
Abdominal wall lift with or without pneumoperitoneum does not seem to offer an advantage over pneumoperitoneum in any of the patient-oriented outcomes for laparoscopic cholecystectomy in people with low anaesthetic risk .