Development and Validation of a Prediction Score for Postoperative Acute Renal Failure Following Liver Resection

Risk prediction models for acute kidney injury following major noncardiac surgery: systematic review

BACKGROUND

Acute kidney injury (AKI) is a serious complication of major noncardiac surgery. Risk prediction models for AKI following noncardiac surgery may be useful for identifying high-risk patients to target with prevention strategies.

METHODS

We conducted a systematic review of risk prediction models for AKI following major noncardiac surgery. MEDLINE, EMBASE, BIOSIS Previews and Web of Science were searched for articles that (i) developed or validated a prediction model for AKI following major noncardiac surgery or (ii) assessed the impact of a model for predicting AKI following major noncardiac surgery that has been implemented in a clinical setting.

RESULTS

We identified seven models from six articles that described a risk prediction model for AKI following major noncardiac surgeries. Three studies developed prediction models for AKI requiring renal replacement therapy following liver transplantation, three derived prediction models for AKI based on the Risk, Injury, Failure, Loss of kidney function, End-stage kidney disease (RIFLE) criteria following liver resection and one study developed a prediction model for AKI following major noncardiac surgical procedures. The final models included between 4 and 11 independent variables, and c-statistics ranged from 0.79 to 0.90. None of the models were externally validated.

CONCLUSIONS

Risk prediction models for AKI after major noncardiac surgery are available; however, these models lack validation, studies of clinical implementation and impact analyses. Further research is needed to develop, validate and study the clinical impact of such models before broad clinical uptake.

Perioperative risk factors for acute kidney injury after liver resection surgery: an historical cohort study

PURPOSE

This study aimed to identify the incidence and risk factors for acute kidney injury (AKI) after liver resection surgery and to clarify the relationship between postoperative AKI and outcome.

METHODS

We conducted a historical cohort study of patients who underwent liver resection surgery with sevoflurane anesthesia from January 2004 to October 2011. Acute kidney injury was diagnosed based on the Acute Kidney Injury Network classification within 72 hr after the surgery. Patient data, surgical and anesthetic data, and laboratory data were extracted manually from the patients' electronic charts. Multivariable logistic regression analysis was used to identify perioperative risk factors for postoperative AKI.

RESULTS

Acute kidney injury was diagnosed in 78 of 642 patients (12.1%; 95% confidence interval [CI]: 9.7 to 14.9). Multivariable analysis showed an independent association between postoperative AKI and preoperative estimated glomerular filtration rate (adjusted odds ratio [aOR] 0.74; 95% CI: 0.64 to 0.85), preoperative hypertension (aOR 2.10; 95% CI: 1.11 to 3.97), and intraoperative red blood cell transfusion (aOR 1.04; 95% CI: 1.01 to 1.07). Development of AKI within 72 hr after liver resection surgery was associated with increased hospital mortality, prolonged length of stay, and increased rates of mechanical ventilation, reintubation, and renal replacement therapy.

CONCLUSION

Perioperative risk factors for AKI after liver resection surgery are similar to those established for other surgical procedures. Further studies are needed to establish causality and to determine whether interventions on modifiable risk factors can reduce the incidence of postoperative AKI and improve patient outcome. This study was registered at the University Hospital Medical Information Network (UMIN) Center (UMIN 000008089).

Epidural analgesia and perioperative kidney function after major liver resection

BACKGROUND

Epidural analgesia (EDA) is a common analgesia regimen in liver resection, and is accompanied by sympathicolysis, peripheral vasodilatation and hypotension in the context of deliberate intraoperative low central venous pressure. This associated fall in mean arterial pressure may compromise renal blood pressure autoregulation and lead to acute kidney injury (AKI). This study investigated whether EDA is a risk factor for postoperative AKI after liver surgery.

METHODS

The incidence of AKI was investigated retrospectively in patients who underwent liver resection with or without EDA between 2002 and 2012. Univariable and multivariable analyses were performed including recognized preoperative and intraoperative predictors of posthepatectomy renal failure.

RESULTS

A series of 1153 patients was investigated. AKI occurred in 8·2 per cent of patients and was associated with increased morbidity (71 versus 47·3 per cent; P = 0·003) and mortality (21 versus 0·3 per cent; P <  0·001) rates. The incidence of AKI was significantly higher in the EDA group (10·1 versus 3·7 per cent; P = 0·003). Although there was no significant difference in the incidence of AKI between patients undergoing minor hepatectomy with or without EDA (5·2 versus 2·7 per cent; P = 0·421), a substantial difference in AKI rates occurred in patients undergoing major hepatectomy (13·8 versus 5·0 per cent; P = 0·025). In multivariable analysis, EDA remained an independent risk factor for AKI after hepatectomy (P = 0·040).

CONCLUSION

EDA may be a risk factor for postoperative AKI after major hepatectomy.

Improving the quality of liver resection: a systematic review and critical analysis of the available prognostic models

BACKGROUND

Liver resection is considered to offer the only hope of cure for patients with liver malignancy. However, there are concerns about its safety, particularly in view of the increasing efficacy of less invasive strategies. No systematic review of prognostic research in liver resections has yet been performed.

METHODS

A systematic search identified articles published between 1999 and 2012 that performed a risk prediction analysis in patients undergoing liver resection. Studies were included if an outcome occurring within 90 days of surgery was identified, multivariable analysis performed and regression coefficients provided. The main endpoints were the outcomes and predictors chosen by the investigators, their definition, the performance and validity of the models, and the quality of the study as assessed using the QUIPS (quality in prognosis studies) tool.

RESULTS

A total of 91 studies were included. Eleven were prospective, but only two of these were registered. Twenty-eight endpoints were identified. These focused on postoperative morbidity or mortality, but many were redundant or ill defined and other relevant patient-reported outcomes were lacking. Predictors were not standardized, were poorly defined and overlapped. Only nine studies assessed the performance of their models and seven made an internal or temporal validation, but none reported an external validation or impact analysis. The median QUIPS score was 34 out of 50, indicating a high risk for bias.

CONCLUSION

Prognostic research in liver resection is still at the developmental stage.

A clinical perspective of the link between metabolic syndrome and hepatocellular carcinoma

Metabolic syndrome (MS), which is defined as a constellation of clinico-biological features closely related to insulin-resistance has reached epidemic levels in Western Europe and Northern America. Non-alcoholic fatty liver disease (NAFLD) represents the hepatic manifestation of MS. As its incidence parallels that of MS, NAFLD is currently becoming one of the most frequent chronic liver diseases in Western countries. On one hand, MS favors the development of hepatocellular carcinoma (HCC) either through NAFLD liver parenchymal alterations (steatosis; steatohepatitis; fibrosis), or in the absence of significant underlying liver parenchyma changes. In this setting, HCC are often diagnosed incidentally, tend to be larger than in patients developing HCC on cirrhosis and therefore frequently require major liver resections. On the other hand, MS patients are at increased risk of both liver-related postoperative complications and increased cardiorespiratory events leading to non-negligible mortality rates following liver surgery. These deleterious effects seem to be related to the existence of impaired liver function even in the absence of severe fibrosis but also higher cardiorespiratory sensitivity in a setting of MS/NAFLD. Hence, specific medical and surgical improvements in the perioperative management of these patients are required. These include complete preoperative cardiorespiratory work-up and the wide use of preoperative liver volume modulation. Finally, the long-term prognosis after curative surgery for MS-related HCC does not seem to be worse than for other HCC occurring on classical chronic liver diseases. This is probably related to less aggressive tumor behavior with lower micro vascular invasion and decreased rates of poorly differentiated lesions. In this setting, several medical therapies including metformin could be of value in the prevention of both occurrence and recurrence of HCC.

The incidence and risk factors of acute kidney injury after hepatobiliary surgery: a prospective observational study

BACKGROUND

Although intraperitoneal surgery is a major operation associated with postoperative acute kidney injury (AKI), the incidence, risk factors, and long-term renal outcome are not well known. We aimed to determine the risk factors and 6 months renal outcome in patients with clinical or subclinical AKI after hepatobiliary surgery. We also assessed the validity of urine neutrophil gelatinase-associated lipocalin (NGAL) in the early detection of AKI or prediction of renal outcome.

METHODS

This prospective observational study enrolled patients with normal renal function who underwent hepatobiliary surgeries. Urine and serum samples were collected for NGAL measurement.

RESULTS

Among 131 patients, 10 (7.6%) developed postoperative AKI. Urine NGAL at 12 h postsurgery was the most predictive parameter for the diagnosis of AKI (cutoff, 92.85 ng/mL). With the cutoff value, subclinical AKI was diagnosed in 42 (32.1%) patients. Patients with clinical AKI and those with subclinical AKI were assigned to the AKI group. The AKI group had significantly higher model for end-stage liver disease and sodium (MELD-Na) score, lower albumin level, and longer hospital stay after surgery than the non-AKI group. Older age and higher MELD-Na score were independent risk factors for the development of postoperative AKI. At 6 months postsurgery, the estimated glomerular filtration rate (eGFR) in the AKI group was significantly lower than that in the non-AKI group, although the baseline eGFR was not different. In multiple linear regression analysis, the maximum urine NGAL level during 24 h postsurgery, intraoperative fluid balance, and having liver transplantation were significantly associated with a poor 6 months renal outcome.

CONCLUSION

Urine NGAL was useful in the early diagnosis of postoperative AKI as well as in predicting the 6 months renal outcome after hepatobiliary surgery. A considerable proportion of patients developed subclinical AKI, and these patients showed worse renal outcome compared with the non-AKI group.

Nitroglycerine and patient position effect on central, hepatic and portal venous pressures during liver surgery

BACKGROUND

To reduce blood loss during liver surgery, a low central venous pressure (CVP) is recommended. Nitroglycerine (NG) with its rapid onset and offset can be used to reduce CVP. In this study, the effect of NG on portal and hepatic venous pressures (PVP and HVP) in different body positions was assessed.

METHODS

Thirteen patients undergoing liver resection were studied. Cardiac output (CO), mean arterial pressure (MAP) and CVP were measured. PVP and HVP were measured using tip manometer catheters at baseline (BL) in horizontal position; during NG infusion, targeting a MAP of 60 mmHg, with NG infusion and the patient placed in 10 head-down position.

RESULTS

NG infusion reduced HVP from 9.7 ± 2.4 to 7.2 ± 2.4, PVP from 12.3 ± 2.2 to 9.7 ± 3.0 and CVP from 9.8 ± 1.9 to 7.2 ± 2.1 mmHg at BL. Head-down tilt during ongoing NG resulted in increases in HVP to 8.2 ± 2.1, PVP to 10.7 ± 3 and CVP to 11 ± 1.9 mmHg. CO at BL was 6.3 ± 1.1, which was reduced by NG to 5.8 ± 1.2. Head-down tilt together with NG infusion restored CO to 6.3 ± 1.0 l/min.

CONCLUSION

NG infusion leads to parallel reductions in CVP, HVP and PVP at horizontal body position. Thus, CVP can be used to guide NG dosage and fluid administration at horizontal position. NG infusion can be used to reduce HVP. Head-down tilt can be used during NG infusion to improve both blood pressure and CO without substantial increase in liver venous pressure. In head-down tilt, CVP dissociates from HVP and PVP.

Development and validation of a prediction score for complications after hepatectomy in hepatitis B-related hepatocellular carcinoma patients

Objective and Background

The aim of the present study was to develop and validate a prediction score for postoperative complications by severity and guide perioperative management and patient selection in hepatitis B-related hepatocellular carcinoma patients undergoing liver resection.

Methods

A total of 1543 consecutive liver resections cases were included in the study. Randomly selected sample set of 70% of the study cohort was used to develop a score to predict complications III–V and the remaining 30% was used to validate the score. Based on the preoperative and predictable intraoperative parameters, logistic regression analysis was used to identify risk factors and create an integer score for the predicting of complication.

Results

American Society of Anesthesiologists category, portal hypertension, major liver resection (more than 3 segments) and extrahepatic procedures were identified as independent predictors for complications III–V by logistic regression analysis. A score system integrating these 4 factors was stratified into three groups and significantly predicted the risk of complications III–V, with a rate of 1.6%, 11.9% and 65.6% for low, moderate and high risk, respectively. Using the score, the complications risk could be predicted accurately in the validation set, without significant differences between predicted (10.4%) and observed (8.4%) risks for complications III–V (P = 0.466).

Conclusions

Based on four preoperative risk factors, we have developed and validated an integer-based risk score to predict postoperative severe complications after liver resection for hepatitis B-related hepatocellular carcinoma patients in high-volume surgical center. This score may contribute to preoperative risk stratification and clinical decision-making.

The effect of preoperative renal insufficiency on postoperative outcomes after major hepatectomy: a multi-institutional analysis of 1,170 patients

BACKGROUND

Renal insufficiency adversely affects outcomes after cardiac and vascular surgery. The effect of preoperative renal insufficiency on outcomes after major hepatectomy is unknown.

STUDY DESIGN

All patients who underwent major hepatectomy (≥3 segments) at 3 institutions from 2000 to 2012 were identified. Resections were performed using low central venous pressure anesthesia. Renal function was analyzed by preoperative serum creatinine (sCr) level. Primary outcomes were major complications (Clavien grade III to V), respiratory failure, renal failure requiring hemodialysis, and 90-day mortality.

RESULTS

One thousand one hundred and seventy patients had preoperative sCr levels available. Renal function was analyzed using sCr dichotomized at 1.8 mg/dL, 1 SD higher than the mean value (0.97 ± 0.79 mg/dL) for the cohort. Twenty-two patients had sCr ≥1.8 mg/dL. Major complications occurred in 279 patients (23.8%), respiratory failure in 62 (5.3%), and renal failure in 31 (2.6%). Ninety-day mortality rate was 5.4%. On multivariate analysis, patients with sCr ≥1.8 mg/dL remained at significantly increased risk for major complications (hazard ratio = 3.94; 95% CI, 1.48-10.49; p = 0.006), respiratory failure (hazard ratio = 4.43; 95% CI, 1.33-14.80; p = 0.014), and renal failure (hazard ratio = 4.75; 95% CI, 1.19-18.97; p = 0.028). Serum Cr ≥1.8 mg/dL was not independently associated with 90-day mortality on multivariate analysis (p = 0.27).

CONCLUSIONS

Preoperative serum creatinine ≥1.8 mg/dL identifies patients at significantly increased risk of postoperative major complications, respiratory failure, and renal failure requiring dialysis. Patients are well selected for major hepatectomy, and few patients with substantial renal insufficiency are deemed operative candidates.

Metabolic syndrome and non-alcoholic fatty liver disease in liver surgery: The new scourges?

The aim of this topic highlight is to review relevant evidence regarding the influence of the metabolic syndrome (MS) and its associated liver manifestation, non-alcoholic fatty liver disease (NAFLD), on the development of liver cancer as well as their impact on the results of major liver surgery. MS and NAFLD, whose incidences are significantly increasing in Western countries, are leading to a changing profile of the patients undergoing liver surgery. A MEDLINE search was performed for relevant articles using the key words "metabolic syndrome", "liver resection", "liver transplantation", "non alcoholic fatty liver disease", "non-alcoholic steatohepatitis" and "liver cancer". On one hand, the MS favors the development of primary liver malignancies (hepatocellular carcinoma and cholangiocarcinoma) either through NAFLD liver parenchymal alterations (steatosis, steatohepatitis, fibrosis) or in the absence of significant underlying liver parenchyma changes. Also, the existence of NAFLD may have a specific impact on colorectal liver metastases recurrence. On the other hand, the postoperative period following partial liver resection and liver transplantation is at increased risk of both postoperative complications and mortality. These deleterious effects seem to be related to the existence of liver specific complications but also higher cardio-vascular sensitivity in a setting of MS/NAFLD. Finally, the long-term prognosis after curative surgery joins that of patients operated on with other types of underlying liver diseases. An increased rate of patients with MS/NAFLD referred to hepatobiliary units has to be expected. The higher operative risk observed in this subset of patients will require specific improvements in their perioperative management.

Systematic review of pathophysiological changes following hepatic resection

OBJECTIVES

Major hepatic resection is now performed frequently and with relative safety, but is accompanied by significant pathophysiological changes. The aim of this review is to describe these changes along with interventions that may help reduce the risk for adverse outcomes after major hepatic resection.

METHODS

The MEDLINE, EMBASE and CENTRAL databases were searched for relevant literature published from January 2000 to December 2011. Broad subject headings were 'hepatectomy/', 'liver function/', 'liver failure/' and 'physiology/'.

RESULTS

Predictable changes in blood biochemistry and coagulation occur following major hepatic resection and alterations from the expected path indicate a complicated course. Susceptibility to sepsis, functional renal impairment, and altered energy metabolism are important sequelae of post-resection liver failure.

CONCLUSIONS

The pathophysiology of post-resection liver failure is difficult to reverse and thus strategies aimed at prevention are key to reducing morbidity and mortality after liver surgery.

Partial Preservation of Segment IV Confers No Benefit When Performing Extended Right Hepatectomy for Colorectal Liver Metastases

Introduction. Reducing the volume of resected liver parenchyma may lead to lower morbidity and mortality. The aim of this study was to determine whether partial preservation of segment IV leads to improved outcomes when undertaking extended right hepatectomy for colorectal liver metastases (CRLM). Materials and Methods. A retrospective analysis of patients undergoing right-sided hepatectomy for CRLM was performed. Rates of 90-day mortality and organ dysfunction were compared in 117 patients undergoing right hepatectomy (n = 85), partially extended right hepatectomy with preservation of part of segment IV (n = 20), and fully extended right hepatectomy (n = 12). Results. The 90-day mortality rate of those undergoing right hepatectomy (3/85) was similar to that of those undergoing extended right hepatectomy (0/12) (P = 1.000) but lower than that of those undergoing partially extended right hepatectomy (4/20) (P = 0.024). The rates of hepatic and renal dysfunction were similar between patients undergoing right hepatectomy, partially extended or extended hepatectomy. Discussion. Preservation of part of segment IV confers little clinical benefit when performing extended right hepatectomy for CRLM.

Renal dysfunction is an independent risk factor for mortality after liver resection and the main determinant of outcome in posthepatectomy liver failure

Introduction. The aim of this study was to assess the interaction of liver and renal dysfunction as risk factors for mortality after liver resection. Materials and Methods. A retrospective analysis of 501 patients undergoing liver resection in a single unit was undertaken. Posthepatectomy liver failure (PHLF) was defined according to the International Study Group of Liver Surgery (ISGLS) definition (assessed on day 5) and renal dysfunction according to RIFLE criteria. 90-day mortality was recorded. Results. Twenty-three patients died within 90 days of surgery (4.6%). The lowest mortality occurred in patients without evidence of PHLF or renal dysfunction (2.7%). The mortality rate in patients with isolated PHLF or renal dysfunction was 20% compared to 45% in patients with both. Diabetes (P = 0.028), renal dysfunction (P = 0.030), and PHLF on day 5 (P = 0.011) were independent predictors of 90-day mortality. Discussion. PHLF and postoperative renal dysfunction are independent predictors of 90-day mortality following liver resection but the predictive value for mortality is significantly higher when failure of both organ systems occurs simultaneously.

Serum arterial lactate concentration predicts mortality and organ dysfunction following liver resection

BACKGROUND

The aim of this study was to determine if the post-operative serum arterial lactate concentration is associated with mortality, length of hospital stay or complications following hepatic resection.

METHODS

Serum lactate concentration was recorded at the end of liver resection in a consecutive series of 488 patients over a seven-year period. Liver function, coagulation and electrolyte tests were performed post-operatively. Renal dysfunction was defined as a creatinine rise of >1.5x the pre-operative value.

RESULTS

The median lactate was 2.8 mmol/L (0.6 to 16 mmol/L) and was elevated (≥2 mmol/L) in 72% of patients. The lactate concentration was associated with peak post-operative bilirubin, prothrombin time, renal dysfunction, length of hospital stay and 90-day mortality (P < 0.001). The 90-day mortality in patients with a post-operative lactate ≥6 mmol/L was 28% compared to 0.7% in those with lactate ≤2 mmol/L. Pre-operative diabetes, number of segments resected, the surgeon's assessment of liver parenchyma, blood loss and transfusion were independently associated with lactate concentration.

CONCLUSIONS

Initial post-operative lactate concentration is a useful predictor of outcome following hepatic resection. Patients with normal post-operative lactate are unlikely to suffer significant hepatic or renal dysfunction and may not require intensive monitoring or critical care.

Risk assessment in patients undergoing liver resection

BACKGROUND

Liver resection is still a risky procedure with high morbidity and mortality. It is significant to predict the morbidity and mortality with some models after liver resection.

DATA SOURCES

The MEDLINE/PubMed, Web of Science, Google Scholar, and Cochrane Library databases were searched using the terms "hepatectomy" and "risk assessment" for relevant studies before August 2012. Papers published in English were included.

RESULTS

Thirty-four original papers were included finally. Some models, such as MELD, APACHE II, E-PASS, or POSSUM, widely used in other populations, are useful to predict the morbidity and mortality after liver resection. Some special models for liver resection are used to predict outcomes after liver resection, such as mortality, liver dysfunction, transfusion, or acute renal failure. However, there is no good scoring system to predict or classify surgical complications because of shortage of internal or external validation.

CONCLUSION

It is important to validate the models for the major complications after liver resection with further internal or external databases.

Preoperative prediction of acute kidney injury--from clinical scores to biomarkers

Early acute kidney injury (AKI) diagnosis in critically ill children has been an important recent research focus because of the known association of AKI with poor outcomes and the requirement of early intervention to mitigate negative effects of AKI. In children having surgery, the preoperative period offers a unique opportunity to predict postoperative acute kidney injury (AKI), well before AKI occurs. Pediatric AKI epidemiologic studies have begun to identify which preoperative factors may predict development of postoperative cardiac surgery. Using these clinical risk factors, it may be possible to derive preoperative clinical risk scores and improve upon our ability to risk-stratify children into AKI treatment trials, pre-emptively provide conservative renal injury prevention strategies, and ultimately improve patient outcomes. Developing risk scores requires rigorous methodology and validation before widespread use. There is little information currently on the use of preoperative biological or physiological biomarkers to predict postoperative AKI, representing an important area of future research. This review will provide an overview of methodology of preoperative risk score development, discuss pediatric-specific issues around deriving such risk scores, including the combination of preoperative clinical and biologic biomarkers for AKI prediction, and suggest future research avenues.

Multimodal treatment strategies in patients undergoing surgery for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the major health problems worldwide, and continues to grow because of its association with hepatitis B and C viruses. In patients with HCC, liver transplantation (LT) and liver resection are the only two curative treatment options. LT remains the best option since it not only removes the tumor, but also the underlying disease. The prerequisite for long-term success of LT for HCC depends on the tumor load and strict selection criteria with regard to the size and number of existing HCC lesions. The need to obtain the optimal benefit from a limited number of grafts has prompted the implementation of well-defined selection criteria that identify patients with early HCC who may benefit from better long-term outcome after LT. Unfortunately, LT can only be proposed in approximately 30% of patients with HCC due to limitations in donor graft availability. In this particular setting, open and laparoscopic surgical resection represent reasonable treatment modalities in noncirrhotic HCC patients. The decision-making process for liver resection should integrate the tumor stage, quality and function of the underlying liver parenchyma, volume of the future liver remnant, and general condition of the patient. In patients with favorable features (solitary tumor, compensated Child-Pugh A cirrhosis, no portal hypertension), the reported 5-year survival rates range between 50 and 70%. In specific cases, liver resection and LT may be combined in the same patient.

Tactile stimulation of the oropharynx elicits sympathoexcitation in conscious humans

Tactile stimulation of the oropharynx (TSO) elicits the gag reflex and increases heart rate (HR) and mean arterial pressure (MAP) in anesthetized patients. However, the interaction between upper-airway defense reflexes and the sympathetic nervous system has not been investigated in conscious humans. In Experiment 1, beat-by-beat measurements of HR, MAP, muscle sympathetic nerve activity (MSNA), and renal vascular resistance (RVR) were measured during TSO and tactile stimulation of the hard palate (Sham) in the supine posture. In Experiment 2, TSO was performed before (pre) and after (post) inhalation of 4% lidocaine via nebulizer. Rate pressure product (RPP) was determined. Compared with Sham, TSO elicited the gag reflex and increased RPP [absolute change (Δ)36 ± 6 vs. 17 ± 5%], MSNA (Δ122 ± 39 vs. 19 ± 19%), and RVR (Δ55 ± 11 vs. 4 ± 4%). This effect occurred within one to two cardiac cycles of TSO. The ΔMAP (12 ± 3 vs. 6 ± 1 mmHg) and the ΔHR (10 ± 3 vs. 3 ± 3 beats/min) were also greater following TSO compared with Sham. Lidocaine inhalation blocked the gag reflex and attenuated increases in MAP (Δpre: 16 ± 2; Δpost: 5 ± 2 mmHg) and HR (Δpre: 12 ± 3; Δpost: 2 ± 2 beats/min) in response to TSO. When mechanically stimulated, afferents in the oropharynx not only serve to protect the airway but also cause reflex increases in MSNA, RVR, MAP, and HR. An augmented sympathoexcitatory response during intubation and laryngoscopy may contribute to perioperative cardiovascular morbidity and mortality.

Metabolic disorders, non-alcoholic fatty liver disease and major liver resection: an underestimated perioperative risk

INTRODUCTION

Despite increasing evidence of an association of metabolic syndrome and liver degeneration, little is known about the results of major hepatic resection in patients with metabolic disorders. Following the observation of some unexplained perioperative deaths following uncomplicated right hepatectomy in patients presenting metabolic disorders, we analyzed the perioperative mortality in such population.

MATERIAL AND METHODS

A retrospective analysis of immediate outcome was performed of patients undergoing right hepatectomy and affected by two or more metabolic disorders (diabetes mellitus, hypertension, dyslipidemia, obesity/overweight) without any other known cause of liver disease from January 2001 to May 2010.

RESULTS

Among 151 patients undergoing right hepatectomy, 30 patients presented two or more metabolic disorders. Perioperative mortality in this group reached 30 % (nine patients). In patients presenting MS (≥3 disorders), mortality reached 54 %. Univariate analysis identified four criteria associated with poor prognosis: MS, perioperative bleeding ≥1,000 mL, middle hepatic vein resection and primary hepatic malignancy. At multivariate analysis, middle hepatic vein resection and underlying primary hepatic malignancy resulted as being related to mortality.

CONCLUSIONS

Patients presenting with multiple metabolic disorders should be carefully evaluated before major liver resection, especially when the procedure is planned for hepatocellular carcinoma and when a middle hepatic vein resection is required.

Pulmonary embolism after elective liver resection: a prospective analysis of risk factors

BACKGROUND & AIMS

Impairment of clotting factors after liver resection (LR) is considered to protect from the risk of pulmonary embolism (PE). We aimed at formally investigating the risk of PE after elective LR.

METHODS

From 2007 to 2009, 410 consecutive patients were prospectively analyzed to assess the risk of postoperative PE after LR with a thoracic CT scan, with or without a CT pulmonary angiography (CTPA). All patients were on a standardized thromboprophylaxis regimen.

RESULTS

PE was diagnosed in 24 (6%) patients within the first 10 postoperative days. Comparison between the PE group (n=24) and the non-PE group (n=386) showed a similar rate of metastatic liver disease (25 vs. 31%, p=0.308) but higher rates of BMI ≥ 25 kg/m(2) (75 vs. 46%, p=0.006), major LR (79 vs. 45%, p=0.003) and normal or minimally fibrotic liver parenchyma (92 vs. 73%, p=0.05). No patients with PE had inherited or acquired coagulation disorders. The 90-day mortality rate was similar in the two groups (4% vs. 3%, p=0.77), but the median hospital stay was longer in the PE group (20(IQR 16-27) vs. 11(IQR 8-16) days, p=0.001). On multivariate analysis, the independent predictors for PE were a BMI ≥ 25 kg/m(2) (adj. OR 5.27), major LR (adj. OR 3.13) and normal or minimally fibrotic liver parenchyma (adj. OR 4.21).

CONCLUSIONS

In addition to patient characteristics (high BMI), major resection and normal liver parenchyma increase the risk of PE after LR. This suggests that specific thromboembolic mechanisms are involved in liver regeneration and advocates more aggressive thromboprophylaxis in the high-risk groups.

Does pharmacological conditioning with the volatile anaesthetic sevoflurane offer protection in liver surgery?

BACKGROUND

A recently published randomized control trial (RCT) showed a protection of the remnant liver from ischemia-reperfusion (I/R) injury by pharmacological pre-conditioning with a volatile anaesthetic in patients undergoing hepatic resection. Whether the continuous application of volatile anaesthetics (pharmacological conditioning) also protects against I/R injury is unknown.

METHODS

Consecutive patients undergoing liver resection with inflow occlusion from 2005-2007 were included in the trial. Two groups of anaesthesia regimens with either continuous application of the volatile anaesthetic sevoflurane (pharmacological conditioning) or continuous infusion of the intravenous (i.v.) anaesthetic propofol (control group) were compared. Endpoints were serum-peak-aspartate aminotransferase (AST)/ alanine aminotranferease (ALT) levels, length of stay (LOS) and intensive care unit (ICU) stays, and the occurrence of post-operative complications.

RESULTS

Two hundred and twenty-seven patients were included. Pharmacological conditioning did not protect the remnant liver from IR injury (adjusted difference for peak-AST:61.9 U/l, 95% confidence interval (CI): -151.7-275.4 U/l, P = 0.568; peak-ALT:136.1 U/l, 95% CI: -113.7-385.9 U/l, P = 0.284) nor reduce LOS (adjusted difference 0.9 days, 95% CI: -2.6-4.3 days, P = 0.622) or ICU stay (1.6 days, 95% CI: -0.2-3.3 days, P = 0.079), and was not associated with reduced complication rates (adjusted OR 1.12, 95% CI:0.6-2.3, P = 0.761) compared with the control group.

CONCLUSION

In this retrospective study, continuous volatile anaesthesia in liver resection does not provide protection of the remnant liver from IR injury compared with continuous i.v. anaesthesia.

Fused 99m-Tc-GSA SPECT/CT imaging for the preoperative evaluation of postoperative liver function: can the liver uptake index predict postoperative hepatic functional reserve?

PURPOSE

To evaluate the role of hepatic asialoglycoprotein receptor analysis in the preoperative estimation of postoperative hepatic functional reserve.

METHODS

We obtained technetium-99m-diethylenetriaminepentaacetic acid-galactosyl human serum albumin (99mTc-GSA) SPECT/CT fusion images in 256 patients with liver disease scheduled for hepatic resection. The liver uptake value corrected for body surface area [LUV(BSA)] and liver uptake ratio (LUR) of the remnant were preoperatively estimated based on the fused images. These values were compared with the postoperative hepatic functional reserve.

RESULTS

Significant correlations were observed between LUV(BSA), LUR, and most conventional indicators of hepatic functional reserve. Postoperatively, nonpreserved liver functional reserve was observed in 15 of the 256 patients (5.8%). Remnant LUV(BSA) showed better correlation than remnant LUR or the other indicators. No patients with remnant LUV(BSA) above 28.0 manifested poor nonpreserved functional reserve. Using a LUV(BSA) of 27.0, it was possible to predict postoperative poor hepatic functional reserve at a sensitivity of 91%, specificity of 81%, and accuracy of 81% postoperatively. According to multivariate analysis, a low remnant LUV(BSA) was the only significant independent predictor of poor hepatic functional reserve.

CONCLUSIONS

Our 99mTc-GSA SPECT/CT fusion imaging method was clinically useful for evaluating regional hepatic function and for predicting postoperative hepatic functional reserve.

Anesthetic Considerations in Hepatectomies under Hepatic Vascular Control

Background. Hazards of liver surgery have been attenuated by the evolution in methods of hepatic vascular control and the anesthetic management. In this paper, the anesthetic considerations during hepatic vascular occlusion techniques were reviewed. Methods. A Medline literature search using the terms "anesthetic," "anesthesia," "liver," "hepatectomy," "inflow," "outflow occlusion," "Pringle," "hemodynamic," "air embolism," "blood loss," "transfusion," "ischemia-reperfusion," "preconditioning," was performed. Results. Task-orientated anesthetic management, according to the performed method of hepatic vascular occlusion, ameliorates the surgical outcome and improves the morbidity and mortality rates, following liver surgery. Conclusions. Hepatic vascular occlusion techniques share common anesthetic considerations in terms of preoperative assessment, monitoring, induction, and maintenance of anesthesia. On the other hand, the hemodynamic management, the prevention of vascular air embolism, blood transfusion, and liver injury are plausible when the anesthetic plan is scheduled according to the method of hepatic vascular occlusion performed.