Hemodynamic effects of portal triad clamping with and without pneumoperitoneum: an echocardiographic study

A self-designed liver circle for on-demand Pringle's manoeuver in laparoscopic liver resection

Background:

Laparoscopic liver resection (LLR) allows minimal incisions and relatively quicker post-operative recovery, while intraoperative massive haemorrhage led to conversion to laparotomy. This study aimed to introduce a new, safe and convenient device to serve as Pringle's manoeuver according to the demand in LLR.

Methods:

A liver circle consisting of a hole and a round stem with an obtuse small head was made by medical silica gel. It was applied in LLR to perform on-demand Pringle's manoeuver and developed its function in inferior vena cava (IVC) occlusion. The time of performing Pringle's manoeuver by liver circle, extracorporeal tourniquet and endo intestinal clip under laparoscopic simulator and LLR was compared.

Results:

The liver circle was successfully applied to perform Pringle's manoeuver, IVC exposure and occlusion. It took less time in the occluding step of Pringle's manoeuver than the extracorporeal tourniquet (4.15 ± 0.35 s vs. 9.90 ± 1.15 s, P < 0.05) and the endo intestinal clip (4.15 ± 0.35 s vs. 47.91 ± 3.98 s, P < 0.05) under LLR. The total manipulating time for Pringle's manoeuver with liver circle remained the shortest, and the advantages were more obvious with increased frequencies of intermittent Pringle's manoeuver.

Conclusion:

The new-designed liver circle is more convenient compared to other techniques in performing Pringle's manoeuver, especially the intermittent Pringle's manoeuver in LLR. It can be used to perform on-demand hepatic blood inflow occlusion in every LLR by pre-circling the hepatoduodenal ligament to control bleeding during surgery. It can also be applied to expose the surgical field of vision and perform IVC occlusion to reduce intraoperative blood loss.

A clinical trial of volume- versus pressure-controlled intraoperative ventilation during laparoscopic bariatric surgeries

BACKGROUND

Intra-operative ventilation is often challenging in patients with morbid obesity undergoing bariatric surgery.

OBJECTIVES

To test the noninferiority of pressure-controlled ventilation (PCV) to volume-controlled ventilation (VCV) in respiratory mechanics.

SETTING

Bariatric Surgery Center, Iran.

METHODS

In a randomized open-labeled clinical trial, 66 individuals with morbid obesity undergoing laparoscopic bariatric surgeries underwent intraoperative ventilation with either PCV or VCV. The measurements taken were peak and mean airway pressures (H₂O), partial pressure of arterial oxygen (PaO₂), partial pressure of arterial carbon dioxide (PaCO₂) and end-tidal carbon dioxide (CO₂). We additionally collected pulse-oximetric oxygen saturation, inspiratory concentration of oxygen (FiO₂), and hemodynamic variables. Data were analyzed with repeated measures over the time of intubation, after peritoneal insufflation, and every 15 minutes, thereafter up to one hour.

RESULTS

PCV mode was successful to sustain adequate ventilation in 97% of the patients, which was similar to the 94% success rate of the VCV mode. Peak airway pressure increased 6 cmH₂O and end-tidal CO₂ rose by 5 mm Hg after abdominal insufflation in both groups (P = .850 and .376). Alveolar-arterial oxygen gradient similarly increased within 30 minutes after tracheal intubation both in PCV and VCV groups, with small trend of being higher in the VCV group. The ratio of dead space to tidal volumes (VD/VT) did not have a meaningful change (P = .724).

CONCLUSION

PCV was noninferior to VCV during laparoscopic bariatric surgery. Either mode of ventilation could be alternatively used during the anesthesia care of these patients.

Modified liver hanging maneuver focusing on outflow control in pure laparoscopic left-sided hepatectomy

BACKGROUND

Outflow control during laparoscopic liver resection necessitates the use of technically demanding procedures since the hepatic veins are fragile and vulnerable to damage during parenchymal transection. The liver hanging maneuver reduces venous backflow bleeding during deep parenchymal transection. The present report describes surgical outcomes and a technique to achieve outflow control during application of the modified liver hanging maneuver in patients undergoing laparoscopic left-sided hepatectomy.

METHODS

A retrospective review was performed of clinical data from 29 patients who underwent laparoscopic left-sided hepatectomy using the modified liver hanging maneuver between February 2013 and March 2017. For this hanging technique, the upper end of the hanging tape was placed on the lateral aspect of the left hepatic vein. The tape was then aligned with the ligamentum venosum. The position of the lower end of the hanging tape was determined according to left-sided hepatectomy type. The hanging tape gradually encircled either the left hepatic vein or the common trunk of the left hepatic vein and middle hepatic vein.

RESULTS

The surgical procedures comprised: left lateral sectionectomy (n = 10); left hepatectomy (n = 17); and extended left hepatectomy including the middle hepatic vein (n = 2). Median operative time was 210 min (range 90-350 min). Median intraoperative blood loss was 200 ml (range 60-600 ml). Two intraoperative major hepatic vein injuries occurred during left hepatectomy. Neither patient developed massive bleeding or air embolism. Postoperative major complications occurred in one patient (3.4%). Median postoperative hospital stay was 7 days (range 4-15 days). No postoperative mortality occurred.

CONCLUSIONS

The present modified liver hanging maneuver is a safe and effective method of outflow control during laparoscopic left-sided hepatectomy.

Bleeding control during laparoscopic liver resection: a review of literature

Despite the established advantages of laparoscopy, bleeding control during laparoscopic liver resection (LLR) is a liver-specific improvement. The 2nd International Consensus Conference on Laparoscopic Liver Resection was held in October 2014 at Morioka, Japan. One of the most capital questions was: What is essential in bleeding control during LLR? In order to correctly address this question, we conducted a comprehensive review of the literature. Essential points based on personal experience of the expert panel are also discussed. A total of 54 publications were identified. Based on this analysis, the working group built these recommendations: (1) a pneumoperitoneum of 10-14 mmHg should be used as it allows a good control of the bleeding without significant modifications of hemodynamics; (2) a low central venous pressure (<5 mmHg) should be used; (3) laparoscopy facilitates inflow and outflow control; and (4) surgeons should be experienced with the use of all surgical devices for liver transection and should master laparoscopic suture before starting LLR. Precoagulation with radiofrequency can be useful, particularly in cases of atypical resection. These recommendations are mostly based on experts' opinions and on B or C quality of evidence grade studies. More prospective data are required to confirm these results.

Laparoscopic liver resection with selective prior vascular control

BACKGROUND

Selective control of vascular inflow can reduce blood loss and transfusion rates and may be particularly efficient in laparoscopic liver resection (LLR). The aim of this study was to evaluate the efficacy of selective prior vascular control (PVC) in patients undergoing laparoscopic or open liver resections (OLR).

METHODS

Between 1999 and 2008, 52 patients underwent LLR with PVC with prospective data collection and were compared with patients undergoing OLR with PVC.

RESULTS

There was no difference in the operative time between the 2 groups. Blood loss and transfusion rates were lower in patients who underwent LLR (367 vs 589 mL, P = .001; 3.8% vs 17.3%, P = .05, respectively). Morbidity did not differ significantly between the 2 groups. Hospital stay was longer in the OLR group (11.0 vs 7.4 days, P = .001).

CONCLUSIONS

PVC during LLR was feasible and improved intraoperative and postoperative results. Selective PVC should be obtained in LLR whenever possible.

Effects of pneumoperitoneum and body position on the morphology of the caudal cava vein analyzed by MRI and plastinated sections

BACKGROUND

Pneumoperitoneum and patient positioning are essential factors during laparoscopic surgical procedures. They cause hemodynamic and anatomical changes in several abdominal organs among which the caudal cava vein (CCV) is involved. Hemodynamic changes in this vein (decreased venous return) have been described in the porcine model, but how the vein morphology and size is affected at different abdominal levels is unknown. We sought to assess the morphological and morphometrical changes in the CCV of the pig caused by pneumoperitoneum and the reverse Trendelenburg position by in vivo magnetic resonance imaging (MRI).

METHODS

Six pigs were scanned via MRI under four situations: S1, control (no pneumoperitoneum); S2, control in the reverse Trendelenburg position; S3, pneumoperitoneum (14 mmHg); and S4, pneumoperitoneum in the reverse Trendelenburg position. MRI and plastinated body sections were used to evaluate the topography, morphology and cross-sectional area of the CCV.

RESULTS

Two portions of the CCV were differentiated: a prehepatic portion (located between the vertebral levels L1-T15) with flat and irregular morphology, and a hepatic portion (between T14-T11) that was almost rounded. The reverse Trendelenburg position caused an increase in the lumen affecting mainly the prehepatic portion, while pneumoperitoneum caused a decrease in the total vascular lumen, exerting a greater effect on the hepatic portion. The combination of both situations resulted in a further decrease in the vascular area and global morphological changes.

CONCLUSIONS

The pneumoperitoneum and reverse Trendelenburg position caused morphological and morphometrical changes in the prehepatic and hepatic portions of the CCV, which should assist in gaining a better understanding of the hemodynamic changes described in the literature.

Anatomical changes due to pneumoperitoneum analyzed by MRI: an experimental study in pigs

PURPOSE

Different effects on cardiovascular and respiratory systems and liver are associated with pneumoperitoneum. This study aimed to determine the morphological changes in the abdominal anatomy as a result of increased intra-abdominal pressure due to pneumoperitoneum using MRI.

METHODS

Ten healthy female pigs were used in this study. MRI studies of the abdomen in supine position were made before the creation of pneumoperitoneum and 1 h after increasing the pressure to 14 mmHg. Changes in area, volume, and longitudinal and transverse length of the liver were measured. The diameters of the lumen of the abdominal aorta, the inferior vena cava and portal vein were observed in three positions along the abdominal cavity. The position of the diaphragm after the induction of pneumoperitoneum was also analyzed.

RESULTS

After induction of pneumoperitoneum, volume and transverse length of the liver was significantly increased, while peak area was decreased. Stenosis in the aortic lumen was observed (P < 0.05). Longitudinal and transverse diameters of the portal lumen were reduced, but significant differences were only found in the longitudinal diameter. Alterations in the diameter of the inferior vena cava lumen were obtained in three analyzed positions, but differences were significant only in two of them. A mean cranial displacement of the diaphragm equal to 25 mm was also observed.

CONCLUSION

Increasing abdominal pressure up to laparoscopic pressure (14 mmHg) provokes morphological changes in the liver, vascular structures and diaphragm. These changes could be related to functional alterations that different organs experience after the induction of pneumoperitoneum.

Vascular clamping in liver surgery: physiology, indications and techniques

This article reviews the historical evolution of hepatic vascular clamping and their indications. The anatomic basis for partial and complete vascular clamping will be discussed, as will the rationales of continuous and intermittent vascular clamping.

Specific techniques discussed and described include inflow clamping (Pringle maneuver, extra-hepatic selective clamping and intraglissonian clamping) and outflow clamping (total vascular exclusion, hepatic vascular exclusion with preservation of caval flow). The fundamental role of a low Central Venous Pressure during open and laparoscopic hepatectomy is described, as is the difference in their intra-operative measurements. The biological basis for ischemic preconditioning will be elucidated. Although the potential dangers of vascular clamping and the development of modern coagulation devices question the need for systemic clamping; the pre-operative factors and unforseen intra-operative events that mandate the use of hepatic vascular clamping will be highlighted.

The learning curve in laparoscopic liver resection: improved feasibility and reproducibility

OBJECTIVE

To evaluate the "learning curve" effect on feasibility and reproducibility of laparoscopic liver resection (LLR).

SUMMARY BACKGROUND DATA

LLR is currently limited to few centers and to few procedures. Its reproducibility is still debated.

METHODS

: Patients undergoing LLR between 1996 and 2008 were included. Indications and type of hepatectomies were compared with those of open resections performed in the same period, considering 3 periods (1996-1999, 2000-2003, and 2004-2008). LLRs were divided into 3 equal groups of 58 cases and technical data and outcomes were compared. Risk-adjusted Cumulative Sum model was used for determining the learning curve based on the need for conversion.

RESULTS

Of 782, 174 (22.3%) patients underwent LLR. Proportion of LLR progressively increased (17.5%, 22.4%, and 24.2%), such as hepatocellular carcinoma (17.6%, 25.6%, and 39.4%, P < 0.05), colorectal metastases (0%, 6.5%, and 13.1%, P < 0.05), major hepatectomies (1.1%, 9.1%, 8.5%, P < 0.05), and right hepatectomies (0%, 13.2%, and 13.1%, P < 0.05). Comparing groups, results of LLR significantly improved in terms of conversion rate (15.5%, 10.3%, and 3.4%, P < 0.05), operative time (210, 180, and 150 minutes, P < 0.05), blood loss (300, 200, and 200 mL, P < 0.05), and morbidity (17.2%, 22.4%, and 3.4%, P < 0.05). Pedicle clamping was less used over time (77.6%, 62.1%, and 17.2%, P < 0.05) and for shorter durations (45, 30, and 20 minutes, P < 0.05). Having adjusted for case-mix, the Cumulative Sum analysis demonstrated a learning curve for laparoscopic hepatectomies of 60 cases.

CONCLUSION

A slow but constant evolution of LLR occurred: indications and magnitude of procedures increased and technical outcomes improved. The learning curve demonstrated in this study suggests that LLR is reproducible in liver units but specific training to advanced laparoscopy is required.

Laparoscopic liver resection-understanding its role in current practice: the Henri Mondor Hospital experience

OBJECTIVE

To report our complete experience with laparoscopic liver resection (LLR) to understand what role it may play in the broader context of liver surgery.

BACKGROUND

The goal of LLR is to extend the benefits of the laparoscopic approach without compromising the fundamental principles of open liver surgery. LLR, however, presents unique technical challenges and its evaluation is made difficult by the restricted indications for this approach, the few centers world-wide experienced in the technique, and the heterogeneity of procedures and pathologies involved.

METHODS

Retrospective analysis of a prospectively maintained database of liver resections from a unit with a comprehensive liver program, including resection and transplantation.

RESULTS

There were 166 laparoscopic liver resections between May 23, 1996 and December 31, 2007, including 100 (60%) for malignant pathology (64 HCC, 3 cholangiocarcinoma, 33 hepatic metastases) and 66 for benign pathology (adenoma, 23; FNH, 19; cystic, 17; other, 7). Numbers of resections for benign indications remained stable over time whereas those for malignant indications increased. There were 31 major resections, 56 left lateral sectionectomies, 28 segmentectomies, and 51 tumorectomies. There was 0% mortality and 15.1% morbidity. Median blood loss was 200 mL, 9 patients (5.4%) required transfusion, and median operating time was 180 minutes. Left lateral sectionectomies demonstrated reduced bleeding (median, 175 vs. 300 mL, P = 0.0015) and faster operating time (median, 170 vs. 180 minutes, P = 0.0265). In the second half of the experience, there was reduced bleeding (median, 200 vs. 300 mL, P = 0.0022) and a lower conversion rate (2.4% vs. 16.9%, P = 0.0015).

CONCLUSIONS

Good patient selection and refined surgical technique are the keys to successful LLR. The indications for resection of asymptomatic benign lesions should not be increased because the laparoscopic approach is available. Hepatocellular carcinomas (HCCs) are more likely to be suitable to a laparoscopic approach than colorectal liver metastases. Left lateral sectionectomy and limited resection of solitary peripheral lesions are particularly suitable while hemihepatectomies remain challenging procedures. LLR requires an ongoing robust audit to identify any emerging problems.

Methods of vascular occlusion for elective liver resections

BACKGROUND

Vascular occlusion is used to reduce blood loss during liver resection surgery. Various methods of vascular occlusion have been suggested.

OBJECTIVES

To compare the benefits and harms of different methods of vascular occlusion during elective liver resection.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until August 2008.

SELECTION CRITERIA

We included randomised clinical trials comparing different methods of vascular occlusion during elective liver resections (irrespective of language or publication status).

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials for inclusion and independently extracted the data. We calculated the risk ratio or mean difference with 95% confidence intervals using fixed-effect and random-effects models based on intention-to-treat or available data analysis.

MAIN RESULTS

Ten trials including 657 patients compared different methods of vascular occlusion. All trials were of high risk of bias. Only one or two trials were included under each comparison. There was no statistically significant differences in mortality, liver failure, or other morbidity between any of the comparisons.Hepatic vascular occlusion does not decrease the blood transfusion requirements. It decreases the cardiac output and increases the systemic vascular resistance. In the comparison between continuous portal triad clamping and intermittent portal triad clamping, four of the five liver failures occurred in patients with chronic liver diseases undergoing the liver resections using continuous portal triad clamping. In the comparison between selective inflow occlusion and portal triad clamping, all four patients with liver failure occurred in the selective inflow occlusion group. There was no difference in any of the other important outcomes in any of the comparisons.

AUTHORS' CONCLUSIONS

In elective liver resection, hepatic vascular occlusion cannot be recommended over portal triad clamping. Intermittent portal triad clamping seems to be better than continuous portal triad clamping at least in patients with chronic liver disease. There is no evidence to support selective inflow occlusion over portal triad clamping. The optimal method of intermittent portal triad clamping is not clear. There is no evidence for any difference between the ischaemic preconditioning followed by vascular occlusion and intermittent vascular occlusion for liver resection in patients with non-cirrhotic livers. Further randomised trials of low risk of bias are needed to determine the optimal technique of vascular occlusion.

WITHDRAWN: Methods of vascular occlusion for elective liver resections

BACKGROUND

Vascular occlusion is used to reduce blood loss during liver resection surgery. There is considerable controversy regarding whether vascular occlusion should be used or not during elective liver resections. The method of vascular occlusion employed is also controversial. There is also considerable debate on the role of ischaemic preconditioning before vascular occlusion.

OBJECTIVES

To assess the advantages (decreased blood loss and peri-operative morbidity) and disadvantages (liver dysfunction from ischaemia) of vascular occlusion during liver resections. To compare the advantages (in decreasing blood loss or decreasing ischaemia-reperfusion injury) and disadvantages of different types of vascular occlusion versus total, continuous portal triad clamping.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until March 2007.

SELECTION CRITERIA

We included randomised clinical trials comparing vascular occlusion versus no vascular occlusion during elective liver resections (irrespective of language or publication status). We also included randomised clinical trials comparing the different methods of vascular occlusion and those investigating the role of ischaemic preconditioning in liver resection.

DATA COLLECTION AND ANALYSIS

We collected the data on the characteristics of the trial, methodological quality of the trials, mortality, morbidity, blood loss, blood transfusion requirements, liver function tests, markers of neutrophil activation, operating time, and hospital stay. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. For each binary outcome we calculated the odds ratio (OR) with 95% confidence intervals (CI) based on intention-to-treat analysis. For continuous outcomes, we calculated the weighted mean difference (WMD) with 95% confidence intervals.

MAIN RESULTS

We identified a total of 16 randomised trials. Five trials including 331 patients compared vascular occlusion (n = 166) versus no vascular occlusion (n = 165). Six trials including 521 patients compared different methods of vascular occlusion. Three trials including 210 patients compared ischaemic preconditioning before continuous portal triad clamping (n = 105) versus no ischaemic preconditioning (n = 105). Two trials including 127 patients compared ischaemic preconditioning before continuous portal triad clamping (n = 63) versus intermittent portal triad clamping (n = 64).The blood loss was significantly lower in vascular occlusion compared with no vascular occlusion. The liver enzymes were significantly elevated in the vascular occlusion group compared with no vascular occlusion. There was no difference in the mortality, liver failure, or other morbidities. Four of the five trials comparing vascular occlusion and no vascular occlusion used intermittent vascular occlusion. Trials comparing complete inflow and outflow occlusion to the liver, ie, hepatic vascular exclusion and portal triad clamping demonstrate significant detrimental haemodynamic changes in hepatic vascular exclusion compared to portal triad clamping. There was no significant difference in the number of units transfused and the number of patients needing transfusion. There was no difference in mortality, liver failure, or morbidity between total and selective methods of portal triad clamping. All four cases of mortality and liver failure in the comparison between the intermittent and continuous portal triad clamping occurred in the continuous portal triad clamping (statistically not significant). Intermittent portal triad clamping does not increase the total blood loss or operating time compared to continuous portal triad clamping.There was no statistically significant difference in the mortality, liver failure, morbidity, blood loss, or haemodynamic changes between ischaemic preconditioning versus no ischaemic preconditioning before continuous portal triad clamping. Liver enzymes used as markers of liver injury were significantly lower in the early post-operative period in the ischaemic preconditioning group. The intensive therapy unit stay and hospital stay were statistically significantly lower in the ischaemic preconditioning group than in the no ischaemic preconditioning group.There was no statistically significant difference in the mortality, liver failure, morbidity, intensive therapy unit stay, or hospital stay between ischaemic preconditioning before continuous portal triad clamping and intermittent portal triad clamping. The blood loss and transfusion requirements were lower in the ischaemic preconditioning group. Aspartate aminotransferase level was lower in the intermittent portal triad clamping group than the ischaemic preconditioning group on the third post-operative day. There was no difference in the peak aspartate aminotransferase levels or in the aspartate aminotransferase levels on first or sixth post-operative days of aspartate aminotransferase .

AUTHORS' CONCLUSIONS

Intermittent vascular occlusion seems safe in liver resection. However, it does not seem to decrease morbidity. Among the different methods of vascular occlusion, intermittent portal triad clamping has most evidence to support the clinical application. Hepatic vascular exclusion cannot be recommended routinely. Ischaemic preconditioning before continuous portal triad clamping may be of clinical benefit in reducing intensive therapy unit and hospital stay.

Laparoscopic liver resection without portal clamping: a prospective evaluation

BACKGROUND

Previous comparative studies have demonstrated that laparoscopic liver resection is associated with more frequent use and longer duration of portal camping than open liver resection, a fact that may partially explain the improvement in operative blood loss reported by most series of laparoscopic liver resection. The aim of this prospective study was to evaluate the real need for portal clamping in laparoscopic liver surgery.

STUDY DESIGN

Surgical outcomes of 40 consecutive patients who underwent laparoscopic liver resection for benign and malignant lesions from September 2005 to August 2007 were evaluate. Portal clamping was not systematically used.

RESULTS

No patient required blood transfusion and median blood loss was 160 ml (range 100-340 ml). Mean operating time was 267 min (range 220-370 min) and portal clamping was necessary in only one patient. Surgical complications included two grade I complication, three grade II, and one case of postoperative hemorrhage (grade III).

CONCLUSIONS

Laparoscopic liver surgery without clamping can be performed safely with low blood loss.

Methods of vascular occlusion for elective liver resections

BACKGROUND

Vascular occlusion is used to reduce blood loss during liver resection surgery. There is considerable controversy regarding whether vascular occlusion should be used or not during elective liver resections. The method of vascular occlusion employed is also controversial. There is also considerable debate on the role of ischaemic preconditioning before vascular occlusion.

OBJECTIVES

To assess the advantages (decreased blood loss and peri-operative morbidity) and disadvantages (liver dysfunction from ischaemia) of vascular occlusion during liver resections. To compare the advantages (in decreasing blood loss or decreasing ischaemia-reperfusion injury) and disadvantages of different types of vascular occlusion versus total, continuous portal triad clamping.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until March 2007.

SELECTION CRITERIA

We included randomised clinical trials comparing vascular occlusion versus no vascular occlusion during elective liver resections (irrespective of language or publication status). We also included randomised clinical trials comparing the different methods of vascular occlusion and those investigating the role of ischaemic preconditioning in liver resection.

DATA COLLECTION AND ANALYSIS

We collected the data on the characteristics of the trial, methodological quality of the trials, mortality, morbidity, blood loss, blood transfusion requirements, liver function tests, markers of neutrophil activation, operating time, and hospital stay. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. For each binary outcome we calculated the odds ratio (OR) with 95% confidence intervals (CI) based on intention-to-treat analysis. For continuous outcomes, we calculated the weighted mean difference (WMD) with 95% confidence intervals.

MAIN RESULTS

We identified a total of 16 randomised trials. Five trials including 331 patients compared vascular occlusion (n = 166) versus no vascular occlusion (n = 165). Six trials including 521 patients compared different methods of vascular occlusion. Three trials including 210 patients compared ischaemic preconditioning before continuous portal triad clamping (n = 105) versus no ischaemic preconditioning (n = 105). Two trials including 127 patients compared ischaemic preconditioning before continuous portal triad clamping (n = 63) versus intermittent portal triad clamping (n = 64). The blood loss was significantly lower in vascular occlusion compared with no vascular occlusion. The liver enzymes were significantly elevated in the vascular occlusion group compared with no vascular occlusion. There was no difference in the mortality, liver failure, or other morbidities. Four of the five trials comparing vascular occlusion and no vascular occlusion used intermittent vascular occlusion. Trials comparing complete inflow and outflow occlusion to the liver, ie, hepatic vascular exclusion and portal triad clamping demonstrate significant detrimental haemodynamic changes in hepatic vascular exclusion compared to portal triad clamping. There was no significant difference in the number of units transfused and the number of patients needing transfusion. There was no difference in mortality, liver failure, or morbidity between total and selective methods of portal triad clamping. All four cases of mortality and liver failure in the comparison between the intermittent and continuous portal triad clamping occurred in the continuous portal triad clamping (statistically not significant). Intermittent portal triad clamping does not increase the total blood loss or operating time compared to continuous portal triad clamping. There was no statistically significant difference in the mortality, liver failure, morbidity, blood loss, or haemodynamic changes between ischaemic preconditioning versus no ischaemic preconditioning before continuous portal triad clamping. Liver enzymes used as markers of liver injury were significantly lower in the early post-operative period in the ischaemic preconditioning group. The intensive therapy unit stay and hospital stay were statistically significantly lower in the ischaemic preconditioning group than in the no ischaemic preconditioning group. There was no statistically significant difference in the mortality, liver failure, morbidity, intensive therapy unit stay, or hospital stay between ischaemic preconditioning before continuous portal triad clamping and intermittent portal triad clamping. The blood loss and transfusion requirements were lower in the ischaemic preconditioning group. Aspartate aminotransferase level was lower in the intermittent portal triad clamping group than the ischaemic preconditioning group on the third post-operative day. There was no difference in the peak aspartate aminotransferase levels or in the aspartate aminotransferase levels on first or sixth post-operative days of aspartate aminotransferase.

AUTHORS' CONCLUSIONS

Intermittent vascular occlusion seems safe in liver resection. However, it does not seem to decrease morbidity. Among the different methods of vascular occlusion, intermittent portal triad clamping has most evidence to support the clinical application. Hepatic vascular exclusion cannot be recommended routinely. Ischaemic preconditioning before continuous portal triad clamping may be of clinical benefit in reducing intensive therapy unit and hospital stay.

Respiratory and haemodynamic effects of volume-controlled vs pressure-controlled ventilation during laparoscopy: a cross-over study with echocardiographic assessment

BACKGROUND

The effects of pressure-controlled (PC) ventilation on the ventilatory and haemodynamic parameters during laparoscopy procedures had not been carefully assessed. This prospective cross-over study was undertaken to compare how volume-controlled (VC) and PC modes could affect pulmonary mechanics, gas exchange, and cardiac function in patients undergoing laparoscopy.

METHODS

Twenty-one patients undergoing laparoscopic urological procedures had their lungs ventilated at the beginning with VC ventilation. PC ventilation was instituted at the end of the VC sequence. Ventilator settings were adjusted to keep tidal volume, respiratory rate, and Fi(o(2)) constant in every mode. A complete set of ventilatory, haemodynamic, and gas exchange parameters was obtained under VC after 40 min of pneumoperitoneum and 20 min after switching for PC. Transoesophageal echocardiography was performed in order to evaluate systolic and diastolic function of the heart.

RESULTS

When VC was switched to PC, peak airway pressure decreased [mean (sd) 32 (6) vs 27 (6) cm H(2)O; P < 0.0001], peak inspiratory flow increased [17 (3) vs 48 (8) litre min(-1); P < 0.0001), and dynamic compliance improved [+15 (8)%]. No difference was noted for static airway pressure, static compliance, and arterial oxygenation. No significant change could be demonstrated in the systolic [left ventricular end-systolic wall stress 66 (16) vs 63 (14) x 10(3) dyn cm(-2) m(-2)] or diastolic function [early diastolic velocity 10.3 (2.5) vs 10.5 (2.7) cm s(-1)].

CONCLUSIONS

In this study, no short-term beneficial effect of PC ventilation could be demonstrated over conventional VC ventilation in patients with pneumoperitoneum.

Laparoscopy as a routine approach for left lateral sectionectomy

BACKGROUND

Since 1997, the authors have performed laparoscopic left lateral sectionectomy of lesions of the liver in preference to open surgery. The aim of this study was to assess the outcome.

METHODS

Between October 1997 and March 2005, 36 laparoscopic left lateral sectionectomies were performed using five trocars and a small incision for specimen retrieval. Liver resection was performed mainly using a harmonic scalpel and staplers. The Pringle manoeuvre was used in 24 patients.

RESULTS

The mean patient age was 55.2 (range 31-80) years. Twelve patients had underlying cirrhosis. Surgery was performed for 20 malignant lesions and 16 benign lesions with a mean size of 42.7 (range 5-110) mm. Conversion to laparotomy occurred in one patient. The mean operating time was 171.5 (range 90-240) min. Operatiing time and use of the Pringle manoeuvre were significantly decreased in the second half of the series. Mean blood loss was 208 (range 50-600) ml. No transfusion was required. There were no deaths. Two patients had postoperative complications (one incisional hernia and one pneumonia). The median postoperative stay was 5.2 days.

CONCLUSION

The laparoscopic approach to left lateral sectionectomy was safe and feasible in this series and could be considered as a routine approach in selected patients.

Laparoscopic liver resection: results for 70 patients

BACKGROUND

Laparoscopy is slowly becoming an established technique for liver resection. This procedure still is limited to centers with experience in both hepatic and laparoscopic surgery. Preliminary reports include mainly minor resections for benign liver conditions and show some advantage in terms of postoperative recovery. The authors report their experience with laparoscopic liver resection, the evolution of the technique, and the results.

METHODS

From 1999 to 2006, 70 laparoscopic liver resections were performed using a procedure similar to resection by laparotomy.

RESULTS

There were 38 malignant tumors (54%) and 32 benign lesions (46%). The malignant tumors were mainly hepatocellular carcinomas (19 of 24 patients had cirrhosis). The tumor mean size was 3.8 +/- 1.9 cm (range, 2.2-8 cm). There were 19 major hepatectomies, 34 uni- or bisegmentomies, and 17 atypical resections. The operative time was 227 +/- 109 min. Conversion to laparotomy was required for seven patients (10%), mainly for continuous bleeding during transection. Nine patients (13%) required blood transfusion. One patient had both brisk bleeding and gas embolism from a tear in the section line of the right hepatic vein requiring laparoscopic suture. Blood loss and transfusion requirements were significantly lower in recent than in early cases and in resections with prior vascular control than in those without such control. Postoperative complications were experienced by 11 patients (16%), including one bleed from the hepatic stump requiring hemostasis and two subphrenic collections requiring percutaneous drainage. One cirrhotic patient died of liver failure after resection of a partially ruptured tumor. No ascites was observed in other cirrhotic patients. The mean hospital stay was 5.9 days.

CONCLUSION

The study results confirm that laparoscopic liver resection, including major hepatectomies, can be safely performed by laparoscopy.

Cardiac Function During Intraperitoneal CO2 Insufflation for Aortic Surgery: A Transesophageal Echocardiographic Study

The effect of laparoscopy on cardiac function is controversial. We hypothesized that cardiac dysfunction related to increased afterload could be predominant in patients undergoing elective abdominal aortic repair. To test this hypothesis, we conducted a transesophageal echocardiographic study in 15 patients during laparoscopic aortic surgery. We systematically assessed left ventricular (LV) and right ventricular (RV) functions. Measurements were obtained in the supine position without pneumoperitoneum and with an intraabdominal pressure of 14 mm Hg. Then, patients were turned to the right lateral position without pneumoperitoneum and intraabdominal pressure was increased to 7 mm Hg and to 14 mm Hg. Pneumoperitoneum induced a 25% arterial blood pressure increase and a 38% increase in LV systolic wall stress. A 25% decrease in LV ejection fraction and an 18% decrease in LV stroke volume were observed, associated with an increase in LV end-systolic volume. LV diastolic function impairment was observed without change in LV end-diastolic volume. Respiratory alterations in superior vena cava diameter were never observed, suggesting that volume status remained optimal. Respiratory changes in RV stroke volume were increased according to intraabdominal pressure and body position, reflecting an increase in RV afterload. In conclusion, peritoneal CO2 insufflation in patients scheduled for laparoscopic aortic surgery could impair LV and RV systolic functions as a consequence of increased afterload.