Improving outcome in patients undergoing liver surgery

Development and validation of a machine learning-based early prediction model for massive intraoperative bleeding in patients with primary hepatic malignancies

BACKGROUND

Surgical resection remains the primary treatment for hepatic malignancies, and intraoperative bleeding is associated with a significantly increased risk of death. Therefore, accurate prediction of intraoperative bleeding risk in patients with hepatic malignancies is essential to preventing bleeding in advance and providing safer and more effective treatment.

AIM

To develop a predictive model for intraoperative bleeding in primary hepatic malignancy patients for improving surgical planning and outcomes.

METHODS

The retrospective analysis enrolled patients diagnosed with primary hepatic malignancies who underwent surgery at the Hepatobiliary Surgery Department of the Fourth Hospital of Hebei Medical University between 2010 and 2020. Logistic regression analysis was performed to identify potential risk factors for intraoperative bleeding. A prediction model was developed using Python programming language, and its accuracy was evaluated using receiver operating characteristic (ROC) curve analysis.

RESULTS

Among 406 primary liver cancer patients, 16.0% (65/406) suffered massive intraoperative bleeding. Logistic regression analysis identified four variables as associated with intraoperative bleeding in these patients: ascites [odds ratio (OR): 22.839; P < 0.05], history of alcohol consumption (OR: 2.950; P < 0.015), TNM staging (OR: 2.441; P < 0.001), and albumin-bilirubin score (OR: 2.361; P < 0.001). These variables were used to construct the prediction model. The 406 patients were randomly assigned to a training set (70%) and a prediction set (30%). The area under the ROC curve values for the model's ability to predict intraoperative bleeding were 0.844 in the training set and 0.80 in the prediction set.

CONCLUSION

The developed and validated model predicts significant intraoperative blood loss in primary hepatic malignancies using four preoperative clinical factors by considering four preoperative clinical factors: ascites, history of alcohol consumption, TNM staging, and albumin-bilirubin score. Consequently, this model holds promise for enhancing individualised surgical planning.

Intermittent selective clamping improves rat liver regeneration by attenuating oxidative and endoplasmic reticulum stress

Intermittent clamping of the portal trial is an effective method to avoid excessive blood loss during hepatic resection, but this procedure may cause ischemic damage to liver. Intermittent selective clamping of the lobes to be resected may represent a good alternative as it exposes the remnant liver only to the reperfusion stress. We compared the effect of intermittent total or selective clamping on hepatocellular injury and liver regeneration. Entire hepatic lobes or only lobes to be resected were subjected twice to 10 min of ischemia followed by 5 min of reperfusion before hepatectomy. We provided evidence that the effect of intermittent clamping can be damaging or beneficial depending to its mode of application. Although transaminase levels were similar in all groups, intermittent total clamping impaired liver regeneration and increased apoptosis. In contrast, intermittent selective clamping improved liver protein secretion and hepatocyte proliferation when compared with standard hepatectomy. This beneficial effect was linked to better adenosine-5′-triphosphate (ATP) recovery, nitric oxide production, antioxidant activities and endoplasmic reticulum adaptation leading to limit mitochondrial damage and apoptosis. Interestingly, transient and early chaperone inductions resulted in a controlled activation of the unfolded protein response concomitantly to endothelial nitric oxide synthase, extracellular signal-regulated kinase-1/2 (ERK1/2) and p38 MAPK activation that favors liver regeneration. Endoplasmic reticulum stress is a central target through which intermittent selective clamping exerts its cytoprotective effect and improves liver regeneration. This procedure could be applied as a powerful protective modality in the field of living donor liver transplantation and liver surgery.

Optimal central venous pressure during partial hepatectomy for hepatocellular carcinoma

BACKGROUND

Low central venous pressure (CVP) affects hemodynamic stability and tissue perfusion. This prospective study aimed to evaluate the optimal CVP during partial hepatectomy for hepatocellular carcinoma (HCC).

METHODS

Ninety-seven patients who underwent partial hepatectomy for HCC had their CVP controlled at a level of 0 to 5 mmHg during hepatic parenchymal transection. The systolic blood pressure (SBP) was maintained, if possible, at 90 mmHg or higher. Hepatitis B surface antigen was positive in 90 patients (92.8%) and cirrhosis in 84 patients (86.6%). Pringle maneuver was used routinely in these patients with clamp/unclamp cycles of 15/5 minutes. The average clamp time was 21.4+/-8.0 minutes. These patients were divided into 5 groups based on the CVP: group A: 0-1 mmHg; B: 1.1-2 mmHg; C: 2.1-3 mmHg; D: 3.1-4 mmHg and E: 4.1-5 mmHg. The blood loss per transection area during hepatic parenchymal transection and the arterial blood gas before and after liver transection were analyzed.

RESULTS

With active fluid load, a constant SBP ≥90 mmHg which was considered as optimal was maintained in 18.6% in group A (95% CI: 10.8%-26.3%); 39.2% in group B (95% CI: 29.5%-48.9%); 72.2% in group C (95% CI: 63.2%-81.1%); 89.7% in group D (95% CI: 83.6%-95.7%); and 100% in group E (95% CI: 100%-100%). The blood loss per transection area during hepatic parenchymal transection decreased with a decrease in CVP. Compared to groups D and E, blood loss in groups A, B and C was significantly less (analysis of variance test, P<0.05). Compared with the baseline, the blood oxygenation decreased significantly when the CVP was reduced. Base excess and HCO3- in groups A and B were significantly decreased compared with those in groups C, D and E (P<0.05).

CONCLUSION

In consideration of blood loss, SBP, base excess and HCO3-, a CVP of 2.1-3 mmHg was optimal in patients undergoing partial hepatectomy for HCC.

Hypoxia-inducible factor-1α and vascular endothelial growth factor in the cardioprotective effects of intermittent hypoxia in rats

OBJECTIVE

This study investigated the effects of short-term intermittent hypoxia (IH) preconditioning on cardiac structure and function in rats and the influence of ischemia reperfusion (I/R) injury. Special attention was then paid to the involvement of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF).

METHODS

Wistar rats were given IH treatment for 1, 7, 14, or 28 days. Some of them were thereafter subject to myocardial infarction surgery. Right ventricle systolic pressure (RVSP), myocardial capillary density (CD), and mRNA/protein expression of HIF-1α, VEGF, and Bcl-2 in rat myocardial tissue were determined. Apoptotic cell number was determined by TUNEL staining, and concentrations of malondialdehyde (MDA) and superoxide dismutase (SOD) were measured.

RESULTS

IH treatment for 1, 7, 14, and 28 days reduced the myocardial infarction size, whereas IH for 28 days increased the RVSP, ratio of right to left ventricle weight (RV/LV+S), and CD. IH up-regulated the mRNA and protein levels of HIF-1α, VEGF, and Bcl-2 both under normal and I/R conditions. The induced expression of HIF-1α and VEGF by IH reached a peak after 7 days of treatment. Moreover, IH for 28 days induced cardiomyocyte apoptosis, whereas prior treatment with IH for 1, 7, 14, and 28 days all markedly attenuated the apoptosis effected by the subsequent I/R injury. IH also decreased the concentrations of MDA but increased those of SOD in myocardial tissue of both in normal rats and following I/R.

CONCLUSIONS

The present study demonstrates that short-term IH protects the heart from I/R injury through inhibiting apoptosis and oxidative stress. The up-regulation of HIF-1α and VEGF by short-term IH may participate in the cardioprotective effect of IH.

Application of selective semi-hepatic vascular occlusion combined with low central venous pressure in hepatectomy

AIM: To investigate the application of selective semi-hepatic vascular occlusion combined with low central venous pressure (LCVP) in hepatectomy, and to analyze its effect on liver and kidney function and systemic haemodynamics.

METHODS: The clinical data for 44 patients with liver diseases who underwent hepatectomy from January 2008 to January 2011 at our hospital were retrospectively analyzed. The patients were randomly divided into an experimental group (group A, n = 22) and a control group (Group B, n = 22). When patients in Group A underwent hepatectomy, the central venous pressure (CVP) was controlled between 2-4 mm Hg (1 mmHg = 0.133 kPa) and blood pressure ≥ 90 mmHg, and selective semi-hepatic vascular occlusion was performed. Conventional surgical treatment was given to patients in group B. Intraoperative blood loss, blood pressure, heart rate, changes in liver and kidney function, postoperative hospital stay, and postoperative complications were compared between the two groups.

RESULTS: Intraoperative blood loss was significantly lower in group A than in group B (350.2 mL ± 175.4 mL vs 450.3 mL ± 135.1 mL, P < 0.05). Serum alanine aminotransferase (ALT) was significantly better in group A than in group B on postoperative days 1 and 3 (day 1: 514.3 U/L ± 215.6 U/L vs 720.2 U/L ± 350.7 U/L, P < 0.05; day 3: 360.1 U/L ± 146.4 U/L vs 489.1 U/L ± 231.5 U/L, P < 0.05). Serum albumin (ALB) on postoperative day 1 was significantly higher in group A than in group B (37.5 g/L ± 2.2 g/L vs 35.4 g/L ± 3.9 g/L, P < 0.05). There were no statistical differences in intraoperative blood pressure (131.1 mmHg ± 18.8 mmHg vs 129.2 mmHg ± 14.7 mmHg, P > 0.05), heart rate (83.1 times/min ± 11.2 times/min vs 75.4 times/min ± 12.3 times/min, P > 0.05), postoperative renal function (P > 0.05), hospital stay (11.3 d ± 2.4 d vs 12.1 d ± 2.2 d, P > 0.05) or rate of complications (18.2% vs 22.7%, P > 0.05) between the two groups.

CONCLUSION: During hepatectomy, selective semi-hepatic vascular occlusion combined with low central venous pressure is effective in reducing intraoperative blood loss, protecting liver function, reducing ischemia-reperfusion injury, and has no significant influence on renal function, postoperative hospital stay and systemic hemodynamics.

Anesthesia for liver transplantation in US academic centers: institutional structure and perioperative care

Investigators at a single institution have shown that the organization of the anesthesia team influences patient outcomes after liver transplant surgery. Little is known about how liver transplant anesthesiologists are organized to deliver care throughout the United States. Therefore, we collected quantitative survey data from adult liver transplant programs in good standing with national governing agencies so that we could describe team structure and duties. Information was collected from 2 surveys in a series of quantitative surveys conducted by the Liver Transplant Anesthesia Consortium. All data related to duties, criteria for team membership, interactions/communication with the multidisciplinary team, and service availability were collected and summarized. Thirty-four of 119 registered transplant centers were excluded (21 pediatric centers and 13 centers not certified by national governing agencies). Private practice sites (26) were later excluded because of a poor response rate. There were minimal changes in the compositions of the programs between the 2 surveys. All academic programs had distinct liver transplant anesthesia teams. Most had set criteria for membership and protocols outlining the preoperative evaluation, attended selection committees, and were always available for transplant surgery. Fewer were involved in postoperative care or were available for patients needing subsequent surgery. Most trends were associated with the center volume. In conclusion, some of the variance in team structure and responsibilities is probably related to resources available at the site of practice. However, similarities in specific duties across all teams suggest some degree of self-initiated specialization.

The nitric oxide pathway--evidence and mechanisms for protection against liver ischaemia reperfusion injury

Ischaemia reperfusion (IR) injury is a clinical entity with a major contribution to the morbidity and mortality of liver surgery and transplantation. A central pathway of protection against IR injury utilizes nitric oxide (NO). Nitric oxide synthase (NOS) enzymes manufacture NO from L-arginine. NO generated by the endothelial NOS (eNOS) isoform protects against liver IR injury, whereas inducible NOS (iNOS)-derived NO may have either a protective or a deleterious effect during the early phase of IR injury, depending on the length of ischaemia, length of reperfusion and experimental model. In late phase hepatic IR injury, iNOS-derived NO plays a protective role. In addition to NOS consumption of L-arginine during NO synthesis, this amino acid may also be metabolized by arginase, an enzyme whose release is increased during prolonged ischaemia, and therefore diverts L-arginine away from NOS metabolism leading to a drop in the rate of NO synthesis. NO most commonly acts through the soluble guanylyl cyclase-cyclic GMP- protein kinase G pathway to ameliorate hepatic IR injury. Both endogenously generated and exogenously administered NO donors protect against liver IR injury. The beneficial effects of NO on liver IR are not, however, universal, and certain conditions, such as steatosis, may influence the protective effects of NO. In this review, the evidence for, and mechanisms of these protective actions of NO are discussed, and areas in need of further research are highlighted.

A fourth dimension in decision making in hepatology

Today, the assessment of liver function in patients suffering from acute or chronic liver disease is based on liver biopsy and blood tests including synthetic function, liver enzymes and viral load, most of which provide only circumstantial evidence as to the degree of hepatic impairment. Most of these tests lack the degree of sensitivity to be useful for follow-up of these patients at the frequency that is needed for decision making in clinical hepatology. Accurate assessment of liver function is essential to determine both short- and long-term prognosis, and for making decisions about liver and non-liver surgery, TIPS, chemoembolization or radiofrequency ablation in patients with chronic liver disease. Liver function tests can serve as the basis for accurate decision-making regarding the need for liver transplantation in the setting of acute failure or in patients with chronic liver disease. The liver metabolic breath test relies on measuring exhaled (13) C tagged methacetin, which is metabolized only by the liver. Measuring this liver-specific substrate by means of molecular correlation spectroscopy is a rapid, non-invasive method for assessing liver function at the point-of-care. The (13) C methacetin breath test (MBT) is a powerful tool to aid clinical hepatologists in bedside decision-making. Our recent findings regarding the ability of point-of-care (13) C MBT to assess the hepatic functional reserve in patients with acute and chronic liver disease are reviewed along with suggested treatment algorithms for common liver disorders.

Hepatic ischaemia-reperfusion injury from bench to bedside

BACKGROUND

Vascular occlusion to prevent haemorrhage during liver resection causes ischaemia-reperfusion (IR) injury. Insights into the mechanisms of IR injury gathered from experimental models have contributed to the development of therapeutic approaches, some of which have already been tested in randomized clinical trials.

METHODS

The review was based on a PubMed search using the terms 'ischemia AND hepatectomy', 'ischemia AND liver', 'hepatectomy AND drug treatment', 'liver AND intermittent clamping' and 'liver AND ischemic preconditioning'; only randomized controlled trials (RCTs) were included.

RESULTS

Twelve RCTs reported on ischaemic preconditioning and intermittent clamping. Both strategies seem to confer protection and allow extension of ischaemia time. Fourteen RCTs evaluating pharmacological interventions, including antioxidants, anti-inflammatory drugs, vasodilators, pharmacological preconditioning and glucose infusion, were identified.

CONCLUSION

Several strategies to prevent hepatic IR have been developed, but few have been incorporated into clinical practice. Although some pharmacological strategies showed promising results with improved clinical outcome there is not sufficient evidence to recommend them.

Reperfusion stress induced during intermittent selective clamping accelerates rat liver regeneration through JNK pathway

BACKGROUND & AIMS

Liver resection includes temporal vascular inflow occlusion resulting in ischemia/reperfusion injury in the remnant liver. Here, we developed a rat model of selective lobe occlusion to isolate reperfusion stress from ischemia and to analyze its effect on liver regeneration.

METHODS

Left lateral and median lobes of liver were either mobilized or subjected twice for 10min to ischemia followed by 5min reperfusion prior to resection while the regenerative lobes were only subjected to reperfusion.

RESULTS

Although intermittent reperfusion stress induced higher levels of serum transaminases, analysis of cell cycle regulators revealed accelerated regenerative response compared to standard partial hepatectomy. The G0/G1 transition occurred before tissue resection, as evidenced by c-fos, junB, and IL-6 induction. Following hepatectomy, Cyclin D1 up-regulation, G1/S transition, and cell division occurred earlier than normal. Unexpectedly, liver mobilization, a component of the clamping procedure, also resulted in earlier G1/S transition. The shortened G1-phase was driven by the c-Jun N-terminal Kinase pathway and was associated with an oxidative stress response as evidenced by the expression of inducible nitric oxide synthase.

CONCLUSION

Intermittent selective clamping of lobes to be resected induced reperfusion stress on remnant liver that was beneficial for liver regeneration, suggesting this procedure could be applied in clinical practice.

The vessel sealing system (LigaSure) in hepatic resection: a randomized controlled trial

OBJECTIVE

The aim of this trial was to verify the new surgical device (the LigaSure vessels sealing system) decrease liver transection time.

SUMMARY BACKGROUND DATA

Among the major goals in hepatic resection are minimization of the operation time and of the blood loss. Preliminary reports have suggested that the vessel sealing system might decrease the liver transection time, which is directly associated with the amount of blood loss.

METHODS

Patients who were scheduled to undergo hepatic resection at the Tokyo University Hospital were assigned, by the minimization method, to either use of the new vessel sealing system (VS group) or the conventional clamp crushing method (CC group) for liver transection. The primary end point was the liver transection time, and the secondary endpoints were the amount of blood loss during the entire operation and during liver transection, length of hospital stay, postoperative liver function, and the incidence of various adverse events. An English-language summary of the protocol was submitted (registration ID: C000000337) to the Clinical Trials Registry managed by the University Hospital Medical Information Network in Japan, which can be accessed commission-free on the internet (Available at: http://www.umin.ac.jp/ctr/index.htm).

RESULTS

From February to December in 2006, a total of 165 patients underwent liver resection for some benign or malignant disease of the liver. Among these patients, 120 were randomly assigned to the CC (n = 60) or the VS (n = 60) group. There was no mortality in either of the 2 groups. The median liver transection time in the VS group was 57 minutes (range: 11-127), similar to that in the CC group (56 [range: 9-269] min, P = 0.64), while there was no difference in the transection speed between the 2 groups (1.16 [0.15-2.26] cm/min vs. 1.10 [0.15-2.66] cm/min, P = 0.95). The amount of blood loss and blood loss per transection area during liver transaction in the VS group was also similar to that in the CC group (median: 315 [25-2415] mL vs. 315 [10-1700] mL; P = 0.80) and (5.04 [1.01-44.2] mL/cm vs. 4.36 [0.15-50.5] mL/cm; P = 0.14), respectively.

CONCLUSIONS

This randomized controlled trial showed that while the vessel sealing system was safe, its use was not associated with any significant decrease of the operation time or blood loss during liver transaction as compared with that of the clamp crushing method.

Liver transplantation complications in the intensive care unit and at 6 months

OBJECTIVE

This study sought to determine the factors that influence the 6-month outcomes of liver transplants.

PATIENTS AND METHODS

One hundred ninety-six variables (donor, recipient, operation, intensive care unit [ICU], evolution at 3 and 6 months) were collected from the first 74 consecutive liver transplantation performed from 2002 to 2004. The primary endpoint was patient survival at 6 months. The statistical analysis included a screening univariate analysis followed by a stepwise logistic regression with forward inclusion to test independent associations and finally generation of receiver-operator characteristic (ROC) curves to evaluate predictive factors.

RESULTS

Patient survival at 6 months was 86%, namely 10 deaths, including 4 intraoperatively and 6 postoperatively due to sepsis. Complications in the ICU were classified as reoperations due to biliary problems, vascular complications, and peritonitis. Late complications included 51% rejection episodes, 24% infections, 11% pleural effusions, and 16% diabetes mellitus. Logistic regression analysis showed independent negative predictors of survival were the number of packed red cells during transplantation, the number of fresh frozen plasma units administered in the ICU, blood urea nitrogen (BUN) concentration in the ICU, and graft complications. The odds ratios of these variables were 10.2, 5.2, 42.1, and 36.9, respectively. The area under the curve (AUC) of the ROC was 0.99; the sensitivity was 94%; and the specificity was 100%. The independent predictors of surgical complications were the length of the operation, the need for pressor support, and the number of fresh frozen plasma units administered in the operating room, with odds ratios of 1.0, 7.7, and 1.1, respectively.

CONCLUSION

This study revealed specific operative and ICU variables that correlated with the evolution of our patients.

Colorectal liver metastasis surgery: analysis of risk factors predicting postoperative complications in relation to the extent of resection

BACKGROUND/AIMS

Despite advances in diagnosis and treatment, the rate of complications after resection for colorectal liver metastases remains high. An awareness of risk factors is essential for the rates of morbidity and mortality to fall to optimal levels.

MATERIALS AND METHODS

Of the 240 patients who underwent resection for the first manifestation of colorectal liver metastases, 49 patients with lobectomy or extended hepatectomy (major resections) and 58 with wedge resections within only one liver segment (minor resections) form the basis of this report. A total of 16 variables were analyzed to find the risk factors linked to postoperative morbidity and mortality.

RESULTS/FINDINGS

Thirty-four patients (31.8%) suffered postoperative complications, and one patient died during the hospital stay (0.9%). In the major resection group, multivariate analysis showed that neoadjuvant chemotherapy [odds ratio (OR): 2.4; p = 0.005], vascular clamping (OR: 1.4; p = 0.008), and intraoperative blood loss with transfusion of three to six packed red cell units (OR: 1.2; p = 0.029) were significantly associated with postoperative morbidity. Vascular clamping was an independent predictor for biliary fistula (OR: 1.2; p = 0.029). Postoperative temporary liver failure was influenced by neoadjuvant chemotherapy (OR: 3.4; p = 0.010), vascular clamping (OR: 1.5; p = 0.015), and requirement of blood transfusion (OR: 2.1; p = 0.016). After minor resections, only a decreased postoperative serum cholinesterase B level was an independent predictor for complications (OR: 2.2; p = 0.001), as well as for hemorrhage (OR: 1.6; p = 0.023). Postoperative mortality was not predicted by any of the factors that were analyzed.

INTERPRETATION/CONCLUSION

Factors for complications differ depending on the extent of colorectal liver metastasis resection. Only knowledge and particular consideration of these factors may provide for an optimal postoperative outcome for the individual patient.

Use of dissecting sealer may affect the early outcome in patients submitted to hepatic resection

BACKGROUND

Many technological devices have been used to avoid intraoperative bleeding during hepatic parenchymal transection and to avoid morbidity and mortality, but until now none is complete. The aim of this work is to prospectively analyze hepatic resection patients treated with a water-cooled high frequency monopolar device in order to evaluate its effectiveness.

PATIENTS AND METHODS

All consecutive patients who underwent liver resection by use of this device, between January 2003 until December 2007, were analyzed prospectively. The following variables were considered: age, sex, kind of disease, kind of liver resection, number of major/minor resections, total operative time and transection time, number and time of clamping, blood loss, time of hospitalization, morbidity, and mortality.

RESULTS

Between January 2003 and December 2007, 26 patients were analyzed prospectively (69% women, 31% men). Ages ranged from 18 to 84 years. Sixty-five percent of patients had a malignant disease; 35%, a benign disease. The procedures performed were two major hepatectomies (7.6%) and 24 minor hepatectomies (92.4%). Hepatic transection was performed in 35 to 150 min. Total operative time range was 120-480 min. The average blood loss was 325 ml (range 50-600 ml). The mean postoperative stays were nine days for all the patient and six days for non-cirrhotic patients.

CONCLUSION

The water-cooled high frequency monopolar device is useful for reducing ischemia-reperfusion damage due to the Pringle maneuver and for reducing the risk of morbidity. However, the Kelly forceps remains the only inexpensive instrument really essential for liver surgery.

Right hepatic lobectomy using the staple technique in 101 patients

BACKGROUND

Application of linear stapling devices for extrahepatic vascular control in liver surgery has been well-established. However, the technique for use of stapling devices in hepatic parenchymal transection is not well defined.

PURPOSE

To describe the safety and efficacy of our technique for use of vascular stapling devices in hepatic parenchymal transection during open right hepatic lobectomy is the purpose of this study.

METHODOLOGY

We reviewed our experience with 101 consecutive open right hepatic lobectomies performed by a single surgeon between January 2003 and July 2006, in which vascular staplers were utilized for the parenchymal transection phase.

RESULTS

Of the 101 patients who underwent resection, 53 (52%) were female. The mean age was 58 years. Malignant disease was the indication for resection in the majority of patients (88%). Of those with cancer, 78% (69 of 89) had metastatic colorectal cancer, 6% (5 of 89) had metastatic neuroendocrine tumor, 4% (4 of 89) had hepatocellular carcinoma, 4% (4 of 89) had cholangiocarcinoma, and the remaining 8% were other metastatic cancers. Twelve patients (12%) underwent resection for hepatic adenoma or symptomatic benign disease (FNH or hemangioma). Forty-eight patients (48%) underwent a major ancillary procedure at the time of hepatic resection. Thirty-nine patients (39%) had a nonanatomic wedge resection of a left lobe lesion, 27 patients (27%) had one or more lesions treated with radiofrequency ablation (RFA), and 6 patients (6%) were treated with a synchronous bowel resection. The median total operative time was 336 min (range 155-620 min). A Pringle maneuver for temporary vascular inflow occlusion was utilized in all cases, with a median time of 9 min (range 4-17 min). Ten patients (10%) required blood transfusion during surgery or in the postoperative period. The maximum transfusion was 2 U of packed red blood cells (PRBC) in seven patients and 1 U of PRBC in three patients. The mean nadir postoperative hematocrit was 28.2. All patients with malignant disease had tumor-free margins at the completion of the procedure. The average hospital length of stay was 6.0 days. One patient (1%) developed a clinically significant bile leak requiring a postoperative endoscopic retrograde cholangiography (ERCP). No patient required reoperation. The 30 and 60-day postoperative survival was 100%.

CONCLUSION

These findings indicate that application of vascular stapling devices for parenchymal transection in major hepatic resection is a safe technique, with low transfusion requirements and minimal postoperative bile leak. The technique allows for rapid transection of the entire right hepatic lobe in under 10 min. Short video clips of the technique will be demonstrated.

Intermittent ischemia but not ischemic preconditioning is effective in restoring bile flow after ischemia reperfusion injury in the livers of aged rats

BACKGROUND/AIMS

Ischemic preconditioning (IPC) and intermittent ischemia (INT) reduce liver injury following ischemia reperfusion in liver resections. Aged livers are at higher risk for ischemia reperfusion injury, but little is known of the effectiveness of IPC and INT in aged livers. The aim of this study was to investigate the effects of IPC and INT on ischemia reperfusion injury in aged livers.

METHODS

A rat model of segmental hepatic ischemia (45 min) and reperfusion (60 min) was used. Bile flow, as an indicator of early hepatocyte damage and dynamic liver function, plasma concentrations of bilirubin, liver marker enzymes, and liver histology were assessed.

RESULTS

In young rats (8-13 weeks), IPC regimes of 10 min clamping and 10 min reperfusion, and 5 min clamping and 30 min reperfusion, restored bile flow to 23 and 42%, respectively, of the initial value, compared to 14 and 88% for continuous clamping and controls, respectively. An INT regime of three cycles of alternating 15 min perfusion and 15 min clamping gave a substantially greater (70%) restoration of bile flow. In aged rats (20-24 months), the IPC regimes did not give any restoration of bile flow. By contrast, the INT regime restored bile flow to 68%. Plasma bilirubin concentrations were lowest in the INT groups, whereas alanine transaminase concentrations for the IPC and INT groups compared with the continuous clamping groups showed no significant differences.

CONCLUSIONS

In young rats, INT is more effective than IPC in restoring the immediate consequences of IP-induced damage to hepatocytes and liver function after ischemia-reperfusion. In aged rats INT, but not IPC, reverses hepatocyte damage and restores liver function. INT may promote better hepatocyte and liver function than IPC following the surgical resection of aged livers.

Review article: the assessment of liver function using breath tests

BACKGROUND

Hepatologists have long sought to develop a test for assessing liver function, but this aim has been stalled by the complexity of the liver and its diverse functions. Results of metabolic tests, including breath tests, correlate with clinical and histological parameters of patients with liver disorders; however, these tests tend to be cumbersome and impractical for everyday use. The recent development of a real-time, point-of-care liver function breath test has made it straightforward to assess the metabolic function of the liver.

AIM

To review the available data on the use of breath tests for assessing liver reserve in various conditions and their application in various clinical hepatology settings.

RESULTS

The (13)C-methacetin breath test enables accurate follow-up of patients with acute or chronic liver damage, where overall hepatic function is significantly suppressed by known causes of liver disorders, including acute, sub-acute or chronic conditions. The metabolic breath test can detect both gradual and spontaneous improvements in liver function and the effects of treatment.

CONCLUSIONS

Breath testing that provides continuous quantification of methacetin metabolism may be a sensitive tool for the diagnosis and follow-up of patients with liver disorders.