Stroke volume variation in hepatic resection: a replacement for standard central venous pressure monitoring

Major liver resections, perioperative issues and posthepatectomy liver failure: A comprehensive update for the anesthesiologist

Significant advances in surgical techniques and relevant medium- and long-term outcomes over the past two decades have led to a substantial expansion in the indications for major liver resections. To support these outstanding results and to reduce perioperative complications, anesthesiologists must address and master key perioperative issues (preoperative assessment, proactive intraoperative anesthesia strategies, and implementation of the Enhanced Recovery After Surgery approach). Intensive care unit monitoring immediately following liver surgery remains a subject of active and often unresolved debate. Among postoperative complications, posthepatectomy liver failure (PHLF) occurs in different grades of severity (A-C) and frequency (9%-30%), and it is the main cause of 90-d postoperative mortality. PHLF, recently redefined with pragmatic clinical criteria and perioperative scores, can be predicted, prevented, or anticipated. This review highlights: (1) The systemic consequences of surgical manipulations anesthesiologists must respond to or prevent, to positively impact PHLF (a proactive approach); and (2) the maximal intensive treatment of PHLF, including artificial options, mainly based, so far, on Acute Liver Failure treatment(s), to buy time waiting for the recovery of the native liver or, when appropriate and in very selected cases, toward liver transplant. Such a clinical context requires a strong commitment to surgeons, anesthesiologists, and intensivists to work together, for a fruitful collaboration in a mandatory clinical continuum.

The effect of an intraoperative patient-specific, surgery-specific haemodynamic algorithm in improving textbook outcomes for hepatobiliary-pancreatic surgery: a multicentre retrospective study

Background

The concept of a "textbook outcome" is emerging as a metric for ideal surgical outcomes. We aimed to evaluate the impact of an advanced haemodynamic monitoring (AHDM) algorithm on achieving a textbook outcome in patients undergoing hepatobiliary-pancreatic surgery.

Methods

This retrospective, multicentre observational study was conducted across private and public teaching sectors in Victoria, Australia. We studied patients managed by a patient-specific, surgery-specific haemodynamic algorithm or via usual care. The primary outcome was the effect of using a patient-specific, surgery-specific AHDM algorithm for achieving a textbook outcome, with adjustment using propensity score matching. The textbook outcome criteria were defined according to the International Expert Delphi Consensus on Defining Textbook Outcome in Liver Surgery and Nationwide Analysis of a Novel Quality Measure in Pancreatic Surgery.

Results

Of the 780 weighted cases, 477 (61.2%, 95% CI: 57.7%-64.6%) achieved the textbook outcome. Patients in the AHDM group had a higher rate of textbook outcomes [n = 259 (67.8%)] than those in the Usual care group [n = 218 (54.8%); p < 0.001, estimated odds ratio (95% CI) 1.74 (1.30-2.33)]. The AHDM group had a lower rate of surgery-specific complications, severe complications, and a shorter hospital length of stay (LOS) [OR 2.34 (95% CI: 1.30-4.21), 1.79 (95% CI: 1.12-2.85), and 1.83 (95% CI: 1.35-2.46), respectively]. There was no significant difference between the groups for hospital readmission and mortality.

Conclusions

AHDM use was associated with improved outcomes, supporting its integration in hepatobiliary-pancreatic surgery. Prospective trials are warranted to further evaluate the impact of this AHDM algorithm on achieving a textbook impact on long-term outcomes.

Awake robotic liver surgery: A case report

BACKGROUND

In recent years, minimally invasive liver resection has become a standard of care for liver tumors. Considering the need to treat increasingly fragile patients, general anesthesia is sometimes avoided due to respiratory complications. Therefore, surgical treatment with curative intent is abandoned in favor of a less invasive and less radical approach. Epidural anesthesia has been shown to reduce respiratory complications, especially in elderly patients with pre-existing lung disease.

CASE SUMMARY

A 77-year-old man with hepatitis-C-virus-related chronic liver disease underwent robotic liver resection for hepatocellular carcinoma. The patient was suffering from hypertension, diabetes and chronic obstructive pulmonary disease. The National Surgical Quality Improvement Program score for developing pneumonia was 9.2%. We planned a combined spinal-epidural anesthesia with conscious sedation to avoid general anesthesia. No modification of the standard surgical technique was necessary. Hemodynamics were stable and bleeding was minimal. The postoperative course was uneventful.

CONCLUSION

Robotic surgery in locoregional anesthesia with conscious sedation could be considered a safe and suitable approach in specialized centers and in selected patients.

Prediction of postoperative complications after hepatectomy with dynamic monitoring of central venous oxygen saturation

BACKGROUND

The usefulness of static monitoring using central venous pressure has been reported for anesthetic management in hepatectomy. It is unclear whether intra-hepatectomy dynamic monitoring can predict the postoperative course. We aimed to investigate the association between intraoperative dynamic monitoring and post-hepatectomy complications. Furthermore, we propose a novel anesthetic management strategy to reduce postoperative complication.

METHODS

From 2018 to 2021, 93 patients underwent hepatectomy at our hospital. Fifty-three patients who underwent dynamic monitoring during hepatectomy were enrolled. Flo Trac system was used for dynamic monitoring. The baseline central venous oxygen saturation (ScvO2) was defined as the average ScvO2 for 30 min after anesthesia induction. ScvO2 fluctuation (ΔScvO2) was defined as the difference between the baseline and minimum ScvO2. Postoperative complications were evaluated using the comprehensive complication index (CCI).

RESULTS

Patients with ΔScvO2 ≥ 10% had significantly higher CCI scores (0 vs. 20.9: p = 0.043). In univariate analysis, patients with higher CCI scores demonstrated significantly higher preoperative C-reactive protein-to-lymphocyte ratio (7.51 vs. 24.49: p = 0.039), intraoperative bleeding (105 vs. 581 ml: p = 0.008), number of patients with major hepatectomy (4/45 vs. 3/8: p = 0.028), and number of patients with ΔScvO2 ≥ 10% (11/45 vs. 6/8; p = 0.010). Multivariate logistic regression analysis revealed that ΔScvO2 ≥ 10% (odds ratio: 9.53, p = 0.016) was the only independent predictor of elevated CCI.

CONCLUSIONS

Central venous oxygen saturation fluctuation during hepatectomy is a predictor of postoperative complications. Anesthetic management based on intraoperative dynamic monitoring and minimizing the change in ScvO2 is a potential strategy for decreasing the risk of post-hepatectomy complications.

The influence of the Pringle maneuver in laparoscopic hepatectomy: continuous monitor of hemodynamic change can predict the perioperatively physiological reservation

Importance

This is the first study to investigate the correlation between intra-operative hemodynamic changes and postoperative physiological status.

Objective

Design settings and participants

Patients receiving laparoscopic hepatectomy were routinely monitored using FloTract for goal-directed fluid management. The Pringle maneuver was routinely performed during parenchymal dissection and the hemodynamic changes were prospectively recorded. We retrospectively analyzed the continuous hemodynamic data from FloTrac to compare with postoperative physiological outcomes.

Exposure

The Pringle maneuver during laparoscopic hepatectomy.

Main outcomes and measures

Results

Stroke volume variation that did not recover from the relief of the Pringle maneuver during the last application of Pringle maneuver predicted elevated postoperative MELD-Na scores.

Conclusions and relevance

The complexity of the hemodynamic data recorded by the FloTrac system during the Pringle Maneuver in laparoscopic hepatectomy can be effectively analyzed using the growth mixture modeling (GMM) method. The results can potentially predict the risk of short-term liver function deterioration.

Guidelines for Perioperative Care for Liver Surgery: Enhanced Recovery After Surgery (ERAS) Society Recommendations 2022

BACKGROUND

Enhanced Recovery After Surgery (ERAS) has been widely applied in liver surgery since the publication of the first ERAS guidelines in 2016. The aim of the present article was to update the ERAS guidelines in liver surgery using a modified Delphi method based on a systematic review of the literature.

METHODS

A systematic literature review was performed using MEDLINE/PubMed, Embase, and the Cochrane Library. A modified Delphi method including 15 international experts was used. Consensus was judged to be reached when >80% of the experts agreed on the recommended items. Recommendations were based on the Grading of Recommendations, Assessment, Development and Evaluations system.

RESULTS

A total of 7541 manuscripts were screened, and 240 articles were finally included. Twenty-five recommendation items were elaborated. All of them obtained consensus (>80% agreement) after 3 Delphi rounds. Nine items (36%) had a high level of evidence and 16 (64%) a strong recommendation grade. Compared to the first ERAS guidelines published, 3 novel items were introduced: prehabilitation in high-risk patients, preoperative biliary drainage in cholestatic liver, and preoperative smoking and alcohol cessation at least 4 weeks before hepatectomy.

CONCLUSIONS

These guidelines based on the best available evidence allow standardization of the perioperative management of patients undergoing liver surgery. Specific studies on hepatectomy in cirrhotic patients following an ERAS program are still needed.

Bioelectrical Impedance Analysis for Preoperative Volemia Assessment in Living Donor Hepatectomy

Donor safety remains an important concern. We introduced preoperative bioelectrical impedance analysis (BIA) in living donor hepatectomy, as it is a practical method for volemia assessment with the advantages of noninvasiveness, rapid processing, easy handling, and it is relatively inexpensive. We analyzed 51 living donors who underwent right hemihepatectomy between July 2015 and May 2022. The ratio of extracellular water:total body water (ECW/TBW; an index of volemic status) was measured. ECT/TBW < 0.378 was correlated to central venous pressure (CVP) < 5 mm Hg in a previous study and we used this value for personalized preoperative management. In the BIA group (n = 21), donors with ECW/TBW ≥ 0.378 (n = 12) required whole-day nothing by mouth (NPO), whereas those with ECW/TBW < 0.378 (n = 9) required midnight NPO, similar to the control group (n = 30). In comparison with the control group, the BIA group had a significantly lower central venous pressure (p < 0.001) from the start of surgery to the end of surgery, leading to a better surgical field grade (p = 0.045) and decreased operative duration (240.5 ± 45.6 vs. 276.5 ± 54.0 min, p = 0.016). A cleaner surgical field (surgical field grade 1) was significantly associated with decreased operative duration (p = 0.001) and estimated blood loss (p < 0.001). Preoperative BIA was the only significant predictor of a cleaner surgical field (odds ratio, 6.914; 95% confidence interval, 1.6985−28.191, p = 0.007). In conclusion, preoperative volemia assessment using BIA can improve operative outcomes by creating a favorable surgical environment in living donor hepatectomy.

High Arterial Lactate Levels after Hepatic Resection Are Associated with Low Oxygen Delivery and Predict Severe Postoperative Complications

High End-Surgery Arterial Lactate Concentration (ES-ALC) predicts poor outcome after hepatectomy. The aim of this study was to identify intraoperative hemodynamic parameters predicting high ES-ALC during elective liver resection. Patients who underwent liver resection between 2017 and 2018, under FloTrac/EV1000TM hemodynamic monitoring, were included. The ES-ALC cutoff best predicting severe postoperative complications was identified. Association between high ES-ALC and preoperative and intraoperative variables was assessed. 108 patients were included; 90-day mortality was 0.9% and severe morbidity 14.8%. ES-ALC cutoff best discriminating severe complications was 5.05 mmol/L. Patients with ES-ALC > 5.0 mmol/L had a relative risk of severe complications of 2.8% (p = 0.004). High ES-ALC patients had longer surgery and ischemia duration, larger blood losses and higher requirements of fluids and blood transfusions. During surgery, hemoglobin concentration and oxygen delivery (DO2) decreased more significantly in patients with high ES-ALC, although they had similar values of stroke volume and cardiac output to those of other patients. At multivariate analysis, surgery duration and lowest recorded DO2 value were the strongest predictors of high ES-ALC. ES-ALC > 5.0 mmol/L in elective liver resection predicts postoperative morbidity and is essentially driven by the impaired DO2. Timely correction of blood losses might prevent the ES-ALC increase.

Perioperative management of living donor liver transplantation: Part 2 - Donors

Living donor liver transplantation was first developed to mitigate the limited access to deceased donor organs in Asia in the 1990s. This alternative liver transplantation method has become a widely practiced and established transplantation option for adult patients suffering with end-stage liver disease, and it has successfully helped address the shortage of deceased donors. The Society for the Advancement of Transplant Anesthesia and the Korean Society of Transplantation Anesthesiologists jointly reviewed published studies on the perioperative management of adult live liver donors undergoing donor hemi-hepatectomy. The goal of the review is to offer transplant anesthesiologists and critical care physicians a comprehensive overview of the perioperative management of adult live donors. We featured the current status, donor selection process, outcomes and complications, surgical procedure, anesthetic management, Enhanced Recovery After Surgery protocols, avoidance of blood transfusion, and considerations for emergency donation. Recent surgical advances, including laparoscopic donor hemi-hepatectomy and robotic laparoscopic donor surgery, are also addressed.

Impact of conventional vs. goal-directed fluid therapy on urethral tissue perfusion in patients undergoing liver surgery: A pilot randomised controlled trial

BACKGROUND

Although fluid administration is a key strategy to optimise haemodynamic status and tissue perfusion, optimal fluid administration during liver surgery remains controversial.

OBJECTIVE

To test the hypothesis that a goal-directed fluid therapy (GDFT) strategy, when compared with a conventional fluid strategy, would better optimise systemic blood flow and lead to improved urethral tissue perfusion (a new variable to assess peripheral blood flow), without increasing blood loss.

DESIGN

Single-centre prospective randomised controlled superiority study.

SETTING

Erasme Hospital.

PATIENTS

Patients undergoing liver surgery.

INTERVENTION

Forty patients were randomised into two groups: all received a basal crystalloid infusion (maximum 2 ml kg-1 h-1). In the conventional fluid group, the goal was to maintain central venous pressure (CVP) as low as possible during the dissection phase by giving minimal additional fluid, while in the posttransection phase, anaesthetists were free to compensate for any presumed fluid deficit. In the GDFT group, patients received in addition to the basal infusion, multiple minifluid challenges of crystalloid to maintain stroke volume (SV) variation less than 13%. Noradrenaline infusion was titrated to keep mean arterial pressure more than 65 mmHg in all patients.

MAIN OUTCOME MEASURE

The mean intra-operative urethral perfusion index.

RESULTS

The mean urethral perfusion index was significantly higher in the GDFT group than in the conventional fluid group (8.70 [5.72 to 13.10] vs. 6.05 [4.95 to 8.75], P = 0.046). SV index (ml m-2) and cardiac index (l min-1 m-2) were higher in the GDFT group (48 ± 9 vs. 33 ± 7 and 3.5 ± 0.7 vs. 2.4 ± 0.4, respectively; P < 0.001). Although CVP was higher in the GDFT group (9.3 ± 2.5 vs. 6.5 ± 2.9 mmHg; P = 0.003), intra-operative blood loss was not significantly different in the two groups.

CONCLUSION

In patients undergoing liver surgery, a GDFT strategy resulted in a higher mean urethral perfusion index than did a conventional fluid strategy and did not increase blood loss despite higher CVP.

TRIAL REGISTRATION

NCT04092608.

Preoperative volume assessment using bioelectrical impedance analysis for minimizing blood loss during hepatic resection

BACKGROUND

Maintaining low central venous pressure (CVP) is an effective strategy to reduce blood loss during hepatic resection. As an alternative to measuring CVP, which requires the placement of a central venous catheter, bioelectrical impedance analysis (BIA) is a noninvasive method recently used for monitoring volume status in critically ill patients.

METHODS

We investigated 192 patients who underwent hepatic resection from January 2017 to December 2020. The ratio of extracellular water:total body water (ECW/TBW), as an index of volume status, was measured using InBody S10 (Biospace, Seoul, Korea). The correlation between the ECW/TBW and CVP was determined, and their influences on operative outcomes were analyzed.

RESULTS

ECW/TBW and CVP showed a significant correlation; an ECW/TBW <0.378 correlated with a CVP <5 mmHg (R² = 0.839, P<0.001). Estimated blood loss (EBL) was significantly increased in patients with an ECW/TBW ≥0.378 compared to those with a ratio <0.378 (508 ± 321 vs. 324 ± 193, mL, P<0.001). Identified predictors for an EBL ≥500 mL were operative time (odds ratio [OR], 1.008; 95% confidence interval [CI], 1.001-1.015; P = 0.021) and an ECW/TBW <0.378 (OR, 0.263; 95% CI, 0.121-0.572; P = 0.001).

CONCLUSIONS

BIA can be utilized for preoperative volume assessment to minimize blood loss during hepatic resection.

Enhanced recovery after surgery: anesthesia-related components

Background: Enhanced recovery after surgery (ERAS) is a multidisciplinary and multimodal evidence-based approach aimed at improving the recovery of surgical patients. Successful implementation of ERAS protocols requires proper perioperative communication and collaboration among surgeons, anesthesiologists, nurses, and other medical personnel.Current Concepts: The anesthesiologist is the clinical leader responsible for the ERAS program. Preoperative patient evaluation, optimization, and patient education are essential components of the ERAS program. The program also involves preoperative fasting and carbohydrate loading to minimize catabolic effects. Selection of an appropriate anesthetic regimen, fluid and temperature management, avoidance of intra/postoperative nausea and vomiting, and multimodal pain management are the key components of ERAS for which the anesthesiologist is responsible.Discussion and Conclusion: Factors that enable the successful implementation of ERAS include the willingness to change to ERAS, formation of multidisciplinary teams to improve cooperation, and support from the hospital management, as well as standardization of order sets and care processes and the appropriate use of audits. As the leader of the ERAS team, the anesthesiologist should be actively involved in comprehensive management of the patient during the perioperative period.

The Effect of Mechanical Ventilation With Low Tidal Volume on Blood Loss During Laparoscopic Liver Resection: A Randomized Controlled Trial

BACKGROUND

Control of bleeding during laparoscopic liver resection (LLR) is important for patient safety. It remains unknown what the effects of mechanical ventilation with varying tidal volumes on bleeding during LLR. Thus, this study aims to investigate whether mechanical ventilation with low tidal volume (LTV) reduces surgical bleeding during LLR.

METHODS

In this prospective, randomized, and controlled clinical study, 82 patients who underwent scheduled LLR were enrolled and randomly received either mechanical ventilation with LTV group (6-8 mL/kg) along with recruitment maneuver (once/30 min) without positive end-expiratory pressure (PEEP) or conventional tidal volume (CTV; 10-12 mL/kg) during parenchymal resection. The estimated volume of blood loss during parenchymal resection and the incidence of postoperative respiratory complications were compared between 2 groups.

RESULT

The estimated volume of blood loss (median [interquartile range {IQR}]) was decreased in the LTV group compared to the CTV group (301 [148, 402] vs 394 [244, 672] mL, P = .009); blood loss per cm2 of transected surface of liver (5.5 [4.1, 7.7] vs 12.2 [9.8, 14.4] mL/cm2, P < .001) and the risk of clinically significant estimated blood loss (>800 mL) were reduced in the LTV group compared to the CTV group (0/40 vs 8/40, P = .003). Blood transfusion was decreased in the LTV group compared to the CTV group (5% vs 20% of patients, P = .043). No patient in the LTV group but 2 patients in the CTV group were switched from LLR to open hepatectomy. Airway plateau pressure was lower in the LTV group compared to the CTV group (mean ± standard deviation [SD]) (12.7 ± 2.4 vs 17.5 ± 3.5 cm H2O, P = .002).

CONCLUSIONS

Mechanical ventilation with LTV may reduce bleeding during laparoscopic liver surgery.

Intraoperative fluid management in hepato-biliary-pancreatic operation using stroke volume variation monitoring: A single-center, open-label, randomized pilot study

TRIAL DESIGN

This investigator-initiated, single-center, open-label, parallel-group, randomized-controlled pilot study was designed to compare the intraoperative fluid balance and perioperative complications in patients undergoing hepato-biliary-pancreatic surgery with or without stroke volume variation (SVV)-guided fluid management.

METHODS

Patients who were aged >18 years and underwent elective major hepato-biliary-pancreatic surgery between June 30, 2015, and August 31, 2016 at our center were randomly assigned to receive SVV-guided or conventional fluid therapy. The intervention group used SVV to determine the patients' volume status. The primary outcome was the total fluid balance per body weight per operation time, and the secondary outcomes were the total amount of intravenous infusion per body weight per operation time and the Sequential Organ Failure Assessment score on postoperative day 1. Patients were randomized by a two-block computer-generated assignment sequence. Masking of patients and assessors was conducted. The patients and assessors were each blinded to the details of the trial; however, the clinicians were not.

RESULTS

Of the 69 patients who were initially eligible, 60 provided informed consent for participation in the study. After randomization, three patients dropped out of the study because of deviations from the protocol or unexpected hypotension, leaving 28 and 29 patients in the intervention and control groups, respectively. Patients in both groups had similar characteristics at baseline. The median (interquartile range [IQR]) intraoperative fluid balance in the control and SVV groups was 6.2 (IQR, 4.9-7.9) and 8.1 (IQR, 5.7-10.5) ml/kg/h, respectively (P = .103). The administered intravenous infusion was significantly higher in the SVV group (median, 10.9; IQR, 8.3-15.3 ml/kg/h) than in the control group (median, 9.5; IQR, 7.7-10.3 ml/kg/h) (P = .011). On postoperative day 1, the PaO2/FiO2 ratio was lower in the SVV group (median, 266; IQR, 261-341) than in the control group (median, 346; IQR, 299-380) (P = .019).

CONCLUSIONS

Use of the SVV-guided fluid management protocol did not reduce intraoperative fluid balance but increased the intraoperative fluid administration and might worsen postoperative oxygenation.

TRIAL REGISTRATION

UMIN000018111.

Utility of the FloTrac™ Sensor for Anesthetic Management of Laparoscopic Surgery in a Patient After Pneumonectomy: A Case Report and Literature Review

BACKGROUND Pneumonectomy is associated with various anatomical changes and potential complications involving the respiratory and cardiovascular systems. How laparoscopic surgery affects cardiorespiratory status in postpneumonectomy patients is yet to be ascertained. Here, we describe the use of the FloTrac™ sensor for the anesthetic management of laparoscopic adrenalectomy in a postpneumonectomy patient. CASE REPORT A 35-year-old woman underwent an extended hysterectomy and right pneumonectomy for retroperitoneal angiosarcoma and lung metastases, respectively. The metastasis was found in her left adrenal gland; therefore, laparoscopic adrenalectomy was scheduled. Spirometry demonstrated the following: forced vital capacity (FVC), 1.90 L (55.6% of predicted value); vital capacity, 53.6%; forced expiratory volume (FEV₁), 1.38 L (47.3% of predicted value); and FEV₁/FVC, 72.4%. The heart and mediastinal structures had shifted into the right hemithorax. Hugh-Jones classification was grade 2. The induction of general anesthesia was planned. The patient was orotracheally intubated and managed with the pressure control ventilation-volume guaranteed mode of ventilation, targeting an expired tidal volume of 6-7 ml/kg, without using PEEP. We evaluated cardiac output (CO), cardiac index (CI), stroke volume (SV), and stroke volume variation (SVV) using a FloTrac™ sensor. After the establishment of pneumoperitoneum, SVV increased. CO and SV decreased slightly; however, the patient's hemodynamic status was stable. After surgery, we extubated the patient in the operating room; she demonstrated good progress and was discharged home on postoperative day 5. CONCLUSIONS We found changes in the values of SVV after pneumoperitoneum in a postpneumonectomy patient. The FloTrac™ sensor may be a minimally invasive and promising monitor for detecting hemodynamic changes associated with laparoscopic surgery in postpneumonectomy patients.

Intra-operative anaesthetic management of older patients undergoing liver surgery

Older patients represent a growing proportion of the general surgical caseload. This includes those undergoing liver resection, with figures rising faster than the rate of population ageing. The physiology of ageing leads to changes in all body systems which may render the provision of safe anaesthesia more challenging than in younger patients. Anaesthesia for liver surgery has specific principles, largely aimed at reducing venous bleeding from the liver, and those related to complex major surgery. This review explores the principles of anaesthesia for liver resection and describes how they may require modification in the older patient. The traditional approach of low central venous pressure anaesthesia in order to reduce bleeding may need to be altered in the presence of a cardiovascular system less able to tolerate hypotension and hypoperfusion. These changes in physiology should also lower the threshold for invasive monitoring. The provision of effective analgesia perioperatively should be tailored to minimise the surgical stress response and opiate use. Careful consideration of general principles of intra-operative care for older patients, such as positioning, drug dosing, avoidance of excessively deep anaesthesia, and maintenance of normothermia are also important given the prolonged, complex nature of liver surgery. This individualised approach, with careful attention to changes in physiology allows liver resections to be undertaken in older patients without increases in mortality.

High-sensitivity microliter blood pressure sensors based on patterned micro-nanostructure arrays

Herein we present a micro-nanostructure integrated liquid pressure sensor, which features an ultra-high sensitivity of 16.71 mbar^-1, a low-pressure regime of 2 mbar, a trace sample volume of less than 1.3 μL and a visible display element. The measurable pressure ranges of the sensors include not only from micro-scale fluids to bulk liquids but also from hydraulic pressures to blood pressures, opening a window for liquid pressure sensing in lab-on-chip platforms, point-of-care diagnostics, and even robotics.

Impact of a goal directed fluid therapy algorithm on postoperative morbidity in patients undergoing open right hepatectomy: a single centre retrospective observational study

Background

Right hepatectomy is a complex procedure that carries inherent risks of perioperative morbidity. To evaluate outcome differences between a low central venous pressure fluid intervention strategy and a goal directed fluid therapy (GDFT) cardiac output algorithm we performed a retrospective observational study. We hypothesized that a GDFT protocol would result in less intraoperative fluid administration, reduced complications and a shorter length of hospital stay.

Methods

Patients undergoing hepatectomy using an established enhanced recovery after surgery (ERAS) programme between 2010 and 2017 were extracted from a prospectively managed electronic hospital database. Inclusion criteria included adult patients, undergoing open right (segments V-VIII) or extended right (segments IV-VIII) hepatectomy. Primary outcome: amount of intraoperative fluid administration used between the two groups. Secondary outcomes: type and amount of vasoactive medications used, the development of predefined postoperative complications, hospital length of stay, and 30-day mortality. Complications were defined by the European Perioperative Clinical Outcome definitions and graded according to Clavien-Dindo classification. The association between GDFT and the amount of fluid and vasoactive medication used was investigated using logistic and linear regression models.

Results

Fifty-eight consecutive patients were identified. 26 patients received GDFT and 32 received Usual care. There were no significant differences in baseline patient characteristics. Less intraoperative fluid was used in the GDFT group: median (IQR) 2000 ml (1175 to 2700) vs. 2750 ml (2000 to 4000) in the Usual care group; p = 0.03. There were no significant differences in the use of vasoactive medications. Postoperative complications were similar: 9 patients (35%) in the GDFT group vs. 18 patients (56%) in the Usual care group; p = 0.10, OR: 0.41; (95%CI: 0.14 to 1.20). Median (IQR) length of stay for patients in the GDFT group was 7 days (6:8) vs. 9 days (7:13) in the Usual care group; incident rate ratio 0.72 (95%CI: 0.56 to 0.93); p = 0.012. There was no difference in perioperative mortality.

Conclusions

In patients undergoing open right hepatectomy with an established ERAS programme, use of GDFT was associated with less intraoperative fluid administration and reduced hospital length of stay when compared to Usual care. There were no significant differences in postoperative complications or mortality.

Trial registration

Australian New Zealand Clinical Trials Registry: no12619000558123 on 10/4/19.

Goal directed fluid therapy for major liver resection: A multicentre randomized controlled trial

Background

The effect a restrictive goal directed therapy (GDT) fluid protocol combined with an enhanced recovery after surgery (ERAS) programme on hospital stay for patients undergoing major liver resection is unknown.

Methods

We conducted a multicentre randomized controlled pilot trial evaluating whether a patient-specific, surgery-specific intraoperative restrictive fluid optimization algorithm would improve duration of hospital stay and reduce perioperative fluid related complications.

Results

Forty-eight participants were enrolled. The median (IQR) length of hospital stay was 7.0 days (7.0:8.0) days in the restrictive fluid optimization algorithm group (Restrict group) vs. 8.0 days (6.0:10.0) in the conventional care group (Conventional group) (Incidence rate ratio 0.85; 95% Confidence Interval 0.71:1.1; p = 0.17). No statistically significant difference in expected number of complications per patient between groups was identified (IRR 0.85; 95%CI: 0.45–1.60; p = 0.60). Patients in the Restrict group had lower intraoperative fluid balances: 808 mL (571:1565) vs. 1345 mL (900:1983) (p = 0.04) and received a lower volume of fluid per kg/hour intraoperatively: 4.3 mL/kg/hr (2.6:5.8) vs. 6.0 mL/kg/hr (4.2:7.6); p = 0.03. No significant differences in the proportion of patients who received vasoactive drugs intraoperatively (p = 0.56) was observed.

Conclusion

In high-volume hepatobiliary surgical units, the addition of a fluid restrictive intraoperative cardiac output-guided algorithm, combined with a standard ERAS protocol did not significantly reduce length of hospital stay or fluid related complications. Our findings are hypothesis-generating and a larger confirmatory study may be justified.

•

Major liver resection is a complex procedure with up to 40% patients experiencing complications.

•

Optimisation of perfusion and oxygen delivery to all organs remain the cornerstone of best hemodynamic care.

•

Traditionally, a low central venous pressure strategy during major liver resection has been used to reduce venous bleeding.

•

The impact of a restrictive cardiac output fluid optimisation algorithm during major liver surgery is unknown.

•

After major hepatobiliary surgery, a fluid restrictive algorithm did not reduce length of hospital stay or complications.

Transesophageal Echocardiographic Measurements of the Superior Vena Cava for Predicting Fluid Responsiveness in Patients Undergoing Invasive Positive Pressure Ventilation

OBJECTIVES

Preoperative fasting, water deprivation, and intraoperative fluid loss and redistribution result in hypovolemia in patients undergoing surgery. Some findings have indicated that the superior vena cava (SVC) diameter and variation, as determined by transesophageal echocardiography during surgery, do not reflect central venous pressure effectively. This study aimed to compare and correlate the SVC diameter and variation with the stroke volume variation for predicting fluid responsiveness in patients undergoing invasive positive pressure ventilation.

METHODS

Thirty-six patients scheduled for elective gastrointestinal surgery under general anesthesia with invasive positive pressure ventilation were included in this study. After anesthesia induction, the stroke volume variation, SVC diameter, mean arterial pressure, central venous pressure, and pulse were recorded, and measurements after fluid challenge were recorded as well. The SVC variation was calculated before and after the fluid challenge.

RESULTS

After the fluid challenge, the SVC diameter markedly increased, whereas the SVC variation and stroke volume variation significantly decreased (P < .05). The optimal cutoff value for the SVC variation was 21.1%, and the area under the curve (AUC) from a receiver operating characteristic curve analysis was 0.849. The optimal cutoff value for the minimal SVC diameter was 1.135 cm, and that AUC was 0.929. In addition, the optimal cutoff value for the maximal SVC diameter was 1.480 cm, and the AUC was 0.862.

CONCLUSIONS

The minimal SVC diameter may be an effective indicator for predicting fluid responsiveness in patients undergoing invasive positive pressure ventilation.

Enhanced recovery after surgery in liver resection: current concepts and controversies

Enhanced recovery after surgery (ERAS) attenuates the stress response to surgery in the perioperative period and hastens recovery. Liver resection is a complex surgical procedure where the enhanced recovery program has been shown to be safe and effective in terms of postoperative outcomes. ERAS programs have been shown to be associated with lower morbidity, shortened postoperative stay, and reduced cost with no difference in mortality and readmission rates. However, there are challenges that are unique to hepatic resection such as safety after epidural catheterization and postoperative coagulopathy, intraoperative fluids and postoperative organ dysfunction, need for low central venous pressure to reduce blood loss, and non-lactate containing intravenous fluids. This narrative review briefly discusses these concerns and controversies and suggests revisiting some of the strong recommendations made by the ERAS society in light of the recent evidence.

The Correlation Between CVP and SVV and Intraoperative Minimal Blood Loss in Living Donor Hepatectomy

BACKGROUND

Blood loss during liver surgery is found to be correlated with central venous pressure (CVP). The aim of the current retrospective study is to find out the cutoff value of CVP and stroke volume variation (SVV), which may increase the risk of having intraoperative blood loss of more than 100 mL during living liver donor hepatectomies.

METHOD AND PATIENTS

Twenty-seven adult living liver donors were divided into 2 groups according to whether they had intraoperative blood loss of less (G1) or more than 100 mL (G2). The mean values of the patients' CVP and SVV at the beginning of the transaction of the liver parenchyma was used as the cutoff point. Its correlation to intraoperative blood loss was evaluated using the χ² test; P < .001 was regarded as significant.

RESULTS

The cutoff points of CVP and SVV were 8 mm Hg and 13% respectively. The odds ratio of having blood loss exceeding 100 mL was 91.25 (P < .001) and 0.36 (P < .001) for CVP and SVV, respectively.

CONCLUSION

CVP less than 5 mm Hg, as suggested by most authors, is not always clinical achievable. Our results show that a value of less than 8 mm Hg or SVV 13% is able to achieve a minimal blood loss of 100 mL during parenchyma transaction during a living donor hepatectomy. Measurements used to lower the CVP or increased SVV in our serial were intravenous fluids restriction and the use of a diuretic.

A Comparative Study of Intraoperative Fluid Management Using Stroke Volume Variation in Liver Resection

Objective:

The aim of this study is to examine whether intraoperative fluid management with stroke volume variation (SVV) can achieve safe intravenous fluid restriction and contribute to decreasing intraoperative blood loss in liver surgery.

Background:

In liver surgery, maintaining the central venous pressure (CVP) at a low level is effective in decreasing intraoperative blood loss. Recently, several studies have suggested that SVV obtained using the FloTrac system demonstrated a better fluid responsiveness than CVP.

Methods:

We enrolled 30 patients undergoing liver resection since May 2015 in this prospective observational study, and we set the SVV target during liver transection at 13%–20% (SVV group). Forty-three cases of liver resection that we performed between January 2014 and March 2015 without using CVP or SVV were used as the Control group. We compared the 2 groups by using intraoperative blood loss as the primary endpoint.

Results:

There was no significant difference in patient characteristics between the 2 groups. The mean SVV during liver transection in the SVV group was 15.6 ± 4.4%. The infusion volume until completion of liver transection in the Control group was 9.4 mL/kg/h, whereas that of the SVV group was 3.3 mL/kg/h, a significantly lower volume (P &lt; 0.001). The median intraoperative blood loss was significantly decreased in the SVV group compared with the Control group (391 versus 1068 mL; P &lt; 0.001). The intraoperative transfusion rate was also significantly decreased in the SVV group.

Conclusion:

We demonstrated that intraoperative management with SVV can achieve safe intravenous fluid restriction and is useful for decrease intraoperative blood loss in liver surgery.

Guidelines for Perioperative Care for Liver Surgery: Enhanced Recovery After Surgery (ERAS) Society Recommendations

BACKGROUND

Enhanced Recovery After Surgery (ERAS) is a multimodal pathway developed to overcome the deleterious effect of perioperative stress after major surgery. In colorectal surgery, ERAS pathways reduced perioperative morbidity, hospital stay and costs. Similar concept should be applied for liver surgery. This study presents the specific ERAS Society recommendations for liver surgery based on the best available evidence and on expert consensus.

METHODS

A systematic review was performed on ERAS for liver surgery by searching EMBASE and Medline. Five independent reviewers selected relevant articles. Quality of randomized trials was assessed according to the Jadad score and CONSORT statement. The level of evidence for each item was determined using the GRADE system. The Delphi method was used to validate the final recommendations.

RESULTS

A total of 157 full texts were screened. Thirty-seven articles were included in the systematic review, and 16 of the 23 standard ERAS items were studied specifically for liver surgery. Consensus was reached among experts after 3 rounds. Prophylactic nasogastric intubation and prophylactic abdominal drainage should be omitted. The use of postoperative oral laxatives and minimally invasive surgery results in a quicker bowel recovery and shorter hospital stay. Goal-directed fluid therapy with maintenance of a low intraoperative central venous pressure induces faster recovery. Early oral intake and mobilization are recommended. There is no evidence to prefer epidural to other types of analgesia.

CONCLUSIONS

The current ERAS recommendations were elaborated based on the best available evidence and endorsed by the Delphi method. Nevertheless, prospective studies need to confirm the clinical use of the suggested protocol.

Goal-directed fluid restriction during brain surgery: a prospective randomized controlled trial

Background

The value of goal-directed fluid therapy in neurosurgical patients, where brain swelling is a major concern, is unknown. The aim of our study was to evaluate the effect of an intraoperative goal-directed fluid restriction (GDFR) strategy on the postoperative outcome of high-risk patients undergoing brain surgery.

Methods

High-risk patients undergoing brain surgery were randomly assigned to a usual care group (control group) or a GDFR group. In the GDFR group, (1) fluid maintenance was restricted to 3 ml/kg/h of a crystalloid solution and (2) colloid boluses were allowed only in case of hypotension associated with a low cardiac index and a high stroke volume variation. The primary outcome variable was ICU length of stay, and secondary outcomes were lactates at the end of surgery, postoperative complications, hospital length of stay, mortality at day 30, and costs.

Results

A total of 73 patients from the GDFR group were compared with 72 patients from the control group. Before surgery, the two groups were comparable. During surgery, the GDFR group received less colloid (1.9 ± 1.1 vs. 3.9 ± 1.6 ml/kg/h, p = 0.021) and less crystalloid (3 ± 0 vs. 5.0 ± 2.8 ml/kg/h, p < 0.001) than the control group. ICU length of stay was shorter (3 days [1–5] vs. 6 days [3–11], p = 0.001) and ICU costs were lower in the GDFR group. The total number of complications (46 vs. 99, p = 0.043) and the proportion of patients who developed one or more complications (19.2 vs. 34.7%, p = 0.034) were smaller in the GDFR group. Hospital length of stay and costs, as well as mortality at 30 day, were not significantly reduced.

Conclusion

In high-risk patients undergoing brain surgery, intraoperative GDFR was associated with a reduction in ICU length of stay and costs, and a decrease in postoperative morbidity.

Trial registration Chinese Clinical Trial Registry ChiCTR-TRC-13003583, Registered 20 Aug, 2013

Central Venous Pressure Drop After Hypovolemic Phlebotomy is a Strong Independent Predictor of Intraoperative Blood Loss During Liver Resection

BACKGROUND

Intraoperative hypovolemic phlebotomy (HP) has been suggested to reduce central venous pressure (CVP) before hepatectomy. This study aimed to analyze the impact of CVP drop after HP on intraoperative blood loss and postoperative renal function.

METHODS

A retrospective review of a prospective database including 100 consecutive patients (43 males and 57 females; mean age, 65 years; range 23-89 years) undergoing liver resection with HP was performed. The primary outcome variable was estimated blood loss (EBL), and the secondary outcome was postoperative serum creatinin (Scr). A multivariate linear regression analysis was performed to identify predictors of intraoperative blood loss.

RESULTS

The median CVP before blood salvage was 8 mmHg (range 4-30 mmHg). The median volume of hypovolemic phlebotomy was 400 ml (range 200-1000 ml). After HP, CVP decreased to a median of 3 mmHg (range -2 to 16 mmHg), resulting in a median CVP drop of 5.5 mmHg (range 2-14 mmHg). The median EBL during liver resection was 165 ml (range 0-800 ml). The median preoperative serum creatinin (Scr) was 0.82 g/dl (range 0.5-1.74 g/dl), and the postoperative Scr on day 1 was 0.74 g/dl (range 0.44-1.68 g/dl). The CVP drop was associated with EBL (P < 0.001). There was no significant impact of CVP drop on postoperative Scr.

CONCLUSION

A CVP drop after HP is a strong independent predictor of EBL during liver resection. The authors advocate the routine use of HP to reduce perioperative blood loss and transfusion rates in liver surgery. As a predictive tool, CVP drop might help surgeons decide whether a laparoscopic approach is safe.

Anesthetic and operative considerations for laparoscopic liver resection

We enumerate the broad range of anesthetic considerations that affect the outcome of patients undergoing laparoscopic liver resection. Key elements for excellent outcomes after laparoscopic liver resection are careful patient selection and risk stratification, appropriate monitoring, techniques to reduce blood loss and transfusion, and active recovery management. Although some of these key elements are the same for open liver operation, there are specific anesthetic considerations of which both the surgical and anesthesia teams must be aware to achieve optimal patient outcomes after laparoscopic liver resection. While unique advantages of laparoscopic liver resection typically include decreased intraoperative bleeding, transfusion requirements, and a lower incidence of postoperative ascites, specific challenges include management of the complicated interplay between low-volume anesthesia and increased intraabdominal pressure due to pneumoperitoneum, with additional considerations regarding circulatory support to treat acute blood loss with need for emergent conversion in some cases. This article will address in detail the preoperative, intraoperative, and postoperative anesthetic considerations for patients undergoing laparoscopic liver resection that both the surgical and anesthesia team should be aware of to optimize outcomes.

Ultrasonographic measurements of the inferior vena cava variation as a predictor of fluid responsiveness in patients undergoing anesthesia for surgery

BACKGROUND

Both hypovolemia and hypervolemia are connected with increased morbidity and mortality in the treatment and prognosis of patients. An accurate assessment of volume state allows the optimization of organ perfusion and oxygen supply. Recently, ultrasonography has been used to detect hypovolemia in critically ill patients and perioperative patients. The objective of our study was to assess the correlation between inferior vena cava (IVC) variation obtained with ultrasound and stroke volume variation (SVV) measured by the Vigileo/FloTrac monitor, as fluid responsiveness indicators, in patients undergoing anesthesia for surgery.

METHODS

Forty patients (American Society of Anesthesiologists grades I and II) scheduled for elective gastrointestinal surgery were enrolled in our study. After anesthesia induction, 6% hydroxyethyl starch solution was administered to patients as an intravenous (IV) fluid. The IVC diameters were measured with ultrasonography. SVV and stroke volume index (SVI) were obtained from the Vigileo monitor. All data were collected both before and after fluid challenge.

RESULTS

Forty patients underwent IVC sonographic measurements and SVV calculation. After fluid challenge, mean arterial pressure, central venous pressure, SVI, and IVC diameters increased significantly, whereas SVV decreased markedly. The correlation coefficient between the increase in SVI and the baseline of IVC variation after an IV fluid was 0.710, and receiver operating characteristic (ROC) curve was 0.85. The correlation coefficient between the increase in SVI and the baseline of SVV was 0.803 with an ROC curve of 0.93. Central venous pressure had no significant correlation with SVI.

CONCLUSIONS

Our data show that IVC variation and SVV proved to be reliable predictors of fluid responsiveness in patients undergoing anesthesia for surgery with mechanical ventilation.

Intraoperative monitoring of stroke volume variation versus central venous pressure in laparoscopic liver surgery: a randomized prospective comparative trial

BACKGROUND

Central venous pressure (CVP) is used as a marker of cardiac preload to control intraoperative blood loss in open hepatectomies, while its reliability in laparoscopy is less certain. The aim of this randomized prospective trial was to evaluate the outcome of laparoscopic resections performed with stroke volume variation (SVV) or CVP monitoring.

METHODS

All candidates for laparoscopic liver resection were assigned randomly to SVV or to CVP groups. Outcome was evaluated included conversion rate, cause of conversion, intraoperative blood loss, need for transfusions, length of surgery and postoperative results.

RESULTS

Ninety consecutive patients were enrolled: both SVV and CVP groups included 45 patients each and were comparable in terms of patient and disease characteristics. A reduced rate of conversion was recorded in the SVV compared to the CVP group (6.7% and 17.8% respectively, p = 0.02). Blood loss was lower in the SVV group (150 mL), compared to the CVP group (300 mL, p = 0.04). Morbidity, mortality, length of stay and functional recovery were comparable. On multivariate analysis, lesion location, extent of hepatectomy and type of cardiac preload monitoring were associated significantly to risk of conversion.

CONCLUSION

SVV monitoring in laparoscopic liver surgery improves intraoperative outcome, thus enhancing the benefits of the minimally-invasive approach and fast-track protocols.

High Stroke Volume Variation Method by Mannitol Administration Can Decrease Blood Loss During Donor Hepatectomy

Optimal fluid management to reduce blood loss during donor hepatectomy is important for maximizing donor safety. Mannitol can induce osmotic diuresis, helping prevent increased intravascular volume status. We therefore evaluated the effect of high stroke volume variation (SVV) method by mannitol administration and fluid restriction on blood loss during donor hepatectomy.In this prospective study, 64 donors scheduled for donor right hepatectomy were included and allocated into 2 groups. In group A, the SVV value of each patient was maintained at 10% to 20% during hepatic resection with 0.5 g/kg mannitol administration and fluid restriction at a rate of 2 to 4 mL/kg/h. In group B, the SVV value was maintained at <10% by fluid administration at a rate of 6 to 10 mL/kg/h without diuretic administration during surgery. Intraoperative blood loss was estimated by the loss of red cell mass. Surgeon satisfaction scores and postoperative outcomes, including acute kidney injury, abnormal chest radiographic findings, and hospital stay duration, were also assessed.SVV during hepatectomy was significantly higher in group A than in group B (11.0 ± 1.7 vs 6.5 ± 1.1, P < 0.001). The red cell mass loss was significantly lower in group A than in group B (145.4 ± 107.6 vs 307.9 ± 110.7 mL, P < 0.001). Surgeon satisfaction scores were higher in group A than in group B (2.8 ± 0.5 vs 2.0 ± 0.6, P < 0.001). The incidence of acute kidney injury, abnormal chest radiographic findings, and duration of hospital stay did not significantly differ between the 2 groups.Maintenance of high SVV by mannitol administration is effective and safe for reducing blood loss during donor hepatectomy.

Relationship between Stroke Volume Variation and Blood Transfusion during Liver Transplantation

BACKGROUND

Intraoperative blood transfusion increases the risk for perioperative mortality and morbidity in liver transplant recipients. A high stroke volume variation (SVV) method has been proposed to reduce blood loss during living donor hepatectomy. Herein, we investigated whether maintaining high SVV could reduce the need for blood transfusion and also evaluated the effect of the high SVV method on postoperative outcomes in liver transplant recipients.

METHODS

We retrospectively analyzed 332 patients who underwent liver transplantation, divided into control (maintaining <10% of SVV during surgery) and high SVV (maintaining 10-20% of SVV during surgery) groups. We evaluated the blood transfusion requirement and hemodynamic parameters, including SVV, as well as postoperative outcomes, such as incidences of acute kidney injury, durations of postoperative intensive care unit and hospital stay, and rates of 1-year mortality.

RESULTS

Mean SVV values were 7.0% ± 1.3% in the control group (n = 288) and 11.2% ± 1.8% in the high SVV group (n = 44). The median numbers of transfused packed red blood cells and fresh frozen plasmas in the high SVV group were significantly lower than those in control group (0 vs. 2 units, P = 0.003; and 0 vs. 3 units, P = 0.033, respectively). No significant between-group differences were observed for postoperative outcomes.

CONCLUSIONS

Maintaining high SVV can reduce the blood transfusion requirement during liver transplantation without worsening postoperative outcomes. These findings provide insights into improving perioperative management in liver transplant recipients.

Fluid management in living donor hepatectomy: Recent issues and perspectives

The importance of the safety of healthy living liver donors is widely recognized during donor hepatectomy which is associated with blood loss, transfusion, and subsequent post-operative morbidity. Although the low central venous pressure (CVP) technique can still be effective, it may not be advantageous concerning the safety of healthy donors undergoing hepatectomy. Emerging evidence suggests that stroke volume variation (SVV), a simple and useful index for fluid responsiveness and preload status in various clinical situations, can be applied as a guide for fluid management to reduce blood loss during living donor hepatectomy. Synthetic colloid solutions are also associated with serious adverse events such as the use of renal replacement therapy and transfusion in critically ill or septic patients. However, it is uncertain whether the intra-operative use of colloid solution is associated with similarly adverse effects in patients undergoing living donor hepatectomy. In this review article we discuss the recent issues regarding the low CVP technique and the high SVV method, i.e., maintaining 10%-20% of SVV, for fluid management in order to reduce blood loss during living donor hepatectomy. In addition, we briefly discuss the effects of intra-operative colloid or crystalloid administration for surgical rather than septic or critically ill patients.

Effect of stroke volume variation-directed fluid management on blood loss during living-donor right hepatectomy: a randomised controlled study

Reducing blood loss is beneficial in living liver donor hepatectomy. Although it has been suggested that maintaining a low central venous pressure is important, it is known that low stroke volume variation may be associated with increased blood loss. Therefore, we compared the effect on blood loss of 40 patients randomly assigned to a high stroke volume variation group (maintaining 10-20% of stroke volume variation) vs 38 patients in a control group (maintaining < 10% stroke volume variation) during living-donor right hepatectomy. Mean (SD) blood loss during donor hepatectomy was significantly lower in the high stroke volume variation group than in the control group: 476 (131) ml vs 836 (341) ml, respectively (p < 0.001). Blood pressure and peri-operative laboratory values did not differ between the two groups. However, in the high stroke volume variation group, central venous pressure values were also significantly lower. We were unable to disentangle the effects of stroke volume variation and central venous pressure, but our results confirm that the two together appear beneficial.

Intraoperative circulatory management using the FloTrac™ system in laparoscopic liver resection

INTRODUCTION

Several studies have shown that maintenance of the central venous pressure at a low level during liver surgery is effective for intraoperative management. However, others have suggested that stroke volume variation (SVV) may be a better predictor of fluid responsiveness than central venous pressure. The purpose of this study is to conduct a new type of circulatory management using the FloTrac(TM) system in laparoscopic liver resection and to evaluate specific fluctuations in SVV.

METHODS

Of the laparoscopic liver resections that we performed between March 2012 and December 2013, we used the FloTrac system for intraoperative circulatory management in 21 cases. We analyzed the data, mainly the average value of SVV.

RESULTS

The average SVV value during liver transection was 5.2%-24.6% (mean, 17.0%), and 18 cases (86%) exceeded the conventional cut-off value (13%). The average SVV value was 4.3%-18.2% (mean, 9.7%) when pneumoperitoneum was not in effect, whereas it was 7.3% greater on average during liver transection (mean, 17.0%). No perioperative complications developed.

CONCLUSION

The average SVV value during laparoscopic liver transection (mean, 17.0%) exceeded the conventional cut-off value, but in this study, no perioperative complications developed, which enabled safe management. We might be able to manage appropriate fluid control using FloTrac system in patients with laparoscopic liver resection. Therefore, it is necessary to set the target SVV and conduct prospective trials to verify the safety margin for intraoperative management in the future.

Intra - operative Anesthesia Management in Patients Undergoing Surgical Irreversible Electroporation of the Pancreas, Liver, Kidney, and Retroperitoneal Tumors

Background:

Irreversible electroporation (IRE) is a relatively new approach to the management of multiple types of locally advanced soft tissue tumors. Unique peri-procedural anesthetic management is needed in the safe and effective delivery of this therapy.

Objectives:

This study analyzed IRE therapy in relation to anesthetic management for our initial cohort and then established and validated a set of best practical guidelines for general anesthesia in patients undergoing IRE for abdominal tumors.

Patients and Methods:

An IRB-approved prospective data collection outcome protocol was utilized. This study was broken up into two cohorts as follows: the initial 38 patients (pts) undergoing IRE in which anesthetic management was not defined or optimized and then a 40-pt validation cohort to establish the most efficacious anesthetic protocols.

Results:

During IRE delivery, a deeper neuromuscular blockade is required to ensure that all retroperitoneal muscle excitation was minimized. In the initial 38-pt cohort, attempts to treat hypertension (median SBP 190, range 185–215 and median diastolic 98, range 91–115) were made with various types of anti-hypertensives with minimal-to-insufficient effects. The established inhalation was sevoflurane with an approximate median dose of 8.0 volume percentage. Analgesic management of continuous remifentanil was utilized with epidural management, which optimized HTN and tolerance to IRE therapy.

Conclusions:

Anesthetic management for IRE of soft tissue deviates from standard anesthetic medical therapy in regards to depth of neuromuscular blockade and analgesic management during IRE energy delivery. However, minor modifications in anesthesia management allow for a safe and efficient patient procedure.

Goal-Directed Fluid Therapy Using Stroke Volume Variation for Resuscitation after Low Central Venous Pressure-Assisted Liver Resection: A Randomized Clinical Trial

BACKGROUND

The optimal perioperative fluid resuscitation strategy for liver resections remains undefined. Goal-directed therapy (GDT) embodies a number of physiologic strategies to achieve an ideal fluid balance and avoid the consequences of over- or under-resuscitation.

STUDY DESIGN

In a prospective randomized trial, patients undergoing liver resection were randomized to GDT using stroke volume variation as an end point or to standard perioperative resuscitation. Primary outcomes measure was 30-day morbidity.

RESULTS

Between 2012 and 2014, one hundred and thirty-five patients were randomized (GDT: n = 69; standard perioperative resuscitation: n = 66). Median age was 57 years and 56% were male. Metastatic disease comprised 81% of patients. Overall (35% GDT vs 36% standard perioperative resuscitation; p = 0.86) and grade 3 morbidity (28% GDT vs 18% standard perioperative resuscitation; p = 0.22) were equivalent. Patients in the GDT arm received less intraoperative fluid (mean 2.0 L GDT vs 2.9 L standard perioperative resuscitation; p < 0.001). Perioperative transfusions were required in 4% (6% GDT vs 2% standard perioperative resuscitation; p = 0.37) and boluses in the postanesthesia care unit were administered to 24% (29% GDT vs 20% standard perioperative resuscitation; p = 0.23). Mortality rate was 1% (2 of 135 patients; both in GDT). On multivariable analysis, male sex, age, combined procedures, higher intraoperative fluid volume, and fluid boluses in the postanesthesia care unit were associated with higher 30-day morbidity.

CONCLUSIONS

Stroke volume variation-guided GDT is safe in patients undergoing liver resection and led to less intraoperative fluid. Although the incidence of postoperative complications was similar in both arms, lower intraoperative resuscitation volume was independently associated with decreased postoperative morbidity in the entire cohort. Future studies should target extensive resections and identify patients receiving large resuscitation volumes, as this population is more likely to benefit from this technique.

Glycemic responses to intermittent hepatic inflow occlusion in living liver donors

The occurrence of glycemic disturbances has been described for patients undergoing intermittent hepatic inflow occlusion (IHIO) for tumor removal. However, the glycemic responses to IHIO in living liver donors are unknown. This study investigated the glycemic response to IHIO in these patients and examined the association between this procedure and the occurrence of hyperglycemia (blood glucose > 180 mg/dL). The data from 154 living donors were retrospectively reviewed. The decision to perform IHIO was made on the basis of the extent of bleeding that occurred during parenchymal dissection. One round of IHIO consisted of 15 minutes of clamping and 5 minutes of unclamping the hepatic artery and portal vein. Blood glucose concentrations were measured at predetermined time points, including the start and end of IHIO. Repeated hyperglycemic episodes occurred after unclamping. The mean maximum intraoperative blood glucose concentration was greater in donors who underwent ≥3 rounds of IHIO versus those who underwent 1 or 2 rounds (169 ± 30 versus 149 ± 31 mg/dL, P = 0.005). The incidence of intraoperative hyperglycemia was also greater in donors who underwent ≥3 rounds of IHIO versus those who underwent 1 or 2 rounds (38.7% versus 7.7%, odds ratio = 7.1, 95% confidence interval = 2.5-20.4, P < 0.001). Donors who did not undergo IHIO and those who underwent 1 or 2 rounds of IHIO exhibited similar maximum glucose concentrations and similar incidence rates of hyperglycemia. In conclusion, IHIO induced repeated hyperglycemic responses in living donors, and donors who underwent ≥3 rounds of IHIO were more likely to experience intraoperative hyperglycemia. These results provide additional information on the risks and benefits of IHIO in living donors.

Anesthesia for hepatobiliary surgery

Hepatobiliary surgery outcomes have significantly improved since the early 1970s. Surgical and anesthetic advances related to patient selection, alternative surgical management options, and reduction of operative blood loss have been important. Postoperative analgesic regimens are being modified to include intrathecal opiates and to embrace enhanced recovery regimens.

Review of anesthesia in liver transplantation

Liver transplantation (LT) is a well-accepted treatment modality of many end-stage liver diseases. The main issue in LT is the shortage of deceased donors to accommodate the needs of patients waiting for such transplants. Live donors have tremendously increased the pool of available liver grafts, especially in countries where deceased donors are not common. The main ethical concern of this procedure is the safety of healthy donors, who undergo a major abdominal surgery not for their own health, but to help cure others. The first part of the review concentrates on live donor selection, preanesthetic evaluation, and intraoperative anesthetic care for living liver donors. The second part reviews patient evaluation, intraoperative anesthesia monitoring, and fluid management of the recipient. This review provides up-to-date information to help improve the quality of anesthesia, and contribute to the success of LT and increase the long-term survival of the recipients.

Intraoperative hyperglycemia during liver resection: predictors and association with the extent of hepatocytes injury

Background

Patients undergoing liver resection are at risk for intraoperative hyperglycemia and acute hyperglycemia is known to induce hepatocytes injury. Thus, we aimed to evaluate whether intraoperative hyperglycemia during liver resection is associated with the extent of hepatic injury.

Methods

This 1 year retrospective observation consecutively enrolled 85 patients undergoing liver resection for hepatocellular carcinoma. Blood glucose concentrations were measured at predetermined time points including every start/end of intermittent hepatic inflow occlusion (IHIO) via arterial blood analysis. Postoperative transaminase concentrations were used as surrogate parameters indicating the extent of surgery-related acute hepatocytes injury.

Results

Thirty (35.5%) patients developed hyperglycemia (blood glucose > 180 mg/dl) during surgery. Prolonged (≥ 3 rounds) IHIO (odds ratio [OR] 7.34, P = 0.004) was determined as a risk factors for hyperglycemia as well as cirrhosis (OR 4.07, P = 0.022), lower prothrombin time (OR 0.01, P = 0.025), and greater total cholesterol level (OR 1.04, P = 0.003). Hyperglycemia was independently associated with perioperative increase in transaminase concentrations (aspartate transaminase, β 105.1, standard error 41.7, P = 0.014; alanine transaminase, β 81.6, standard error 38.1, P = 0.035). Of note, blood glucose > 160 or 140 mg/dl was not associated with postoperative transaminase concentrations.

Conclusions

Hyperglycemia during liver resection might be associated with the extent of hepatocytes injury. It would be rational to maintain blood glucose concentration < 180 mg/dl throughout the surgery in consideration of parenchymal disease, coagulation status, lipid profile, and the cumulative hepatic ischemia in patients undergoing liver resection for hepatocellular carcinoma.

Restrictive blood transfusion protocol in liver resection patients reduces blood transfusions with no increase in patient morbidity

BACKGROUND

Management of anemia in surgical oncology patients remains one of the key quality components in overall care and cost. Continued reports demonstrate the effects of hospital transfusion, which has been demonstrated to lead to a longer length of stay, more complications, and possibly worse overall oncologic outcomes. The hypothesis for this study was that a dedicated restrictive transfusion protocol in patients undergoing hepatectomy would lead to less overall blood transfusion with no increase in overall morbidity.

METHODS

A cohort study was performed using our prospective database from January 2000 to June 2013. September 2011 served as the separation point for the date of operation criteria because this marked the implementation of more restrictive blood transfusion guidelines.

RESULTS

A total of 186 patients undergoing liver resection were reviewed. The restrictive blood transfusion guidelines reduced the percentage of patients that received blood from 31.0% before January 9, 2011 to 23.3% after this date (P = .03). The liver procedure that was most consistently associated with higher levels of transfusion was a right lobectomy (16%). Prior surgery and endoscopic stent were the 2 preoperative interventions associated with receiving blood. Patients who received blood before and after the restrictive period had similar predictive factors: major hepatectomies, higher intraoperative blood loss, lower preoperative hemoglobin level, older age, prior systemic chemotherapy, and lower preoperative nutritional parameters (all P < .05). Patients who received blood did not have worse overall progression-free survival or overall survival.

CONCLUSIONS

A restrictive blood transfusion protocol reduces the incidence of blood transfusions and the number of packed red blood cells transfused. Patients who require blood have similar preoperative and intraoperative factors that cannot be mitigated in oncology patients. Restrictive use of blood transfusions can reduce cost and does adversely affect patients undergoing liver resection.