Jose A. Melendez

Perioperative outcomes of major hepatic resections under low central venous pressure anesthesia : Blood loss, blood transfusion, and the risk of postoperative renal dysfunction

BACKGROUND We have previously demonstrated that maintenance of a low central venous pressure (LCVP) combined with extrahepatic control of venous outflow reduced the overall blood loss during major hepatic resections. This study examined the overall outcomes and, in particular, renal morbidity associated with a large series of consecutive major liver resections performed with this approach. In addition, the rationale for the anesthetic management to maintain LCVP was carefully reviewed. STUDY DESIGN All major hepatectomies performed between December 1991 and April 1997 were reviewed. The prospective Hepatobiliary Surgical Service database was merged with the Memorial Hospital Laboratory and Blood Bank databases to yield the nature of the operation, blood loss, blood product transfusions, outcomes, and levels of preoperative, postoperative, and discharge serum creatinine and blood urea nitrogen. RESULTS A total of 496 LCVP-assisted major liver resections were performed, with no intraoperative deaths and an in-hospital mortality rate of 3.8%. The median blood loss was 645 mL. Sixty-seven percent of the patients did not require perioperative blood transfusion during surgery and the immediate 12 hours after surgery. The median number of blood transfusions was 2. Only 3% of the patients experienced a persistent and clinically significant increase in serum creatinine possibly attributable to the anesthetic technique. Renal failure directly attributable to the anesthetic technique did not occur. CONCLUSIONS Major resection with LCVP allowed easy control of the hepatic veins before and during parenchymal transection. The anesthetic technique, designed to maintain LCVP during the critical stages of hepatic resection, not only helped to minimize blood loss and mortality but also preserved renal function.

Extended hepatic resection: a 6-year retrospective study of risk factors for perioperative mortality.

BACKGROUND Extended hepatic resection (more than four liver segments) is a major operative procedure that is associated with significant risk. The purpose of this study was to assess the impact of perioperative variables on in-hospital mortality after extended hepatectomy. STUDY DESIGN Consecutive patients who underwent extended hepatic resection were studied. The prognostic value of 29 perioperative variables was evaluated using in-hospital mortality as the endpoint. For each variable, the odds ratio (95% confidence interval) for in-hospital mortality was calculated. Those variables with a lower confidence limit > 1 were considered important risk factors. The population was stratified into categories of patients having the same number of risk factors, and mortality was estimated for each group. These data were used to develop a risk assessment algorithm. RESULTS There were 14 deaths (6%) in 226 patients. Three preoperative variables (cholangitis, creatinine > 1.3 mg/dL, and total bilirubin > 6 mg/dL) and two operative variables (blood loss > 3 L and vena caval resection) appear to be important factors for in-hospital mortality. The mortality associated with the presence of any two of the five factors was 100% (5 of 5), and the mortality associated with the absence of these factors was 3% (6 of 191). CONCLUSIONS Perioperative evaluation of patients undergoing extended hepatic resection should include the quantitation of mortality risk factors. The combination of any two factors among preoperative cholangitis, elevated serum creatinine, elevated serum bilirubin, high operative blood loss, and vena cava resection may carry a high mortality risk. These results require prospective validation.

Predictive respiratory complication quotient predicts pulmonary complications in thoracic surgical patients

BACKGROUND This study was designed to develop an accurate preoperative index of prediction of outcome and hospital charges after lung resection with standard available pulmonary tests in a tertiary cancer center. METHODS Sixty-one consecutive patients undergoing pulmonary resections were evaluated. All patients underwent spirometry, carbon monoxide diffusion capacity, split lung function testing, and room air blood gas analysis at rest and after a 2-minute step climb. The thoracic prospective data base and patient charts were reviewed for length of hospitalization, postoperative length of stay, and complications requiring therapy. Logistic regression analysis of the preoperative data, operation and postoperative outcome was used to develop a new postoperative predictive index: the predictive respiratory complication quotient (PRQ). We describe the design of the equation for the probability of serious pulmonary complications, hospital stay, and hospital charges based on PRQ. RESULTS Ten of 12 patients with a PRQ less than 2,200 suffered serious pulmonary complications of pneumonia, respiratory insufficiency, hypoxemia, and death. Forty-nine patients with a PRQ more than 2,200 did not experience any pulmonary complications. Postoperative length of stay and hospital charges correlated with the PRQ. CONCLUSIONS A construct such as the PRQ may provide a better prediction of outcome than its individual parts. We identified an important underlying relationship between intensive care unit stay, hospital stay and charges, and our index. A PRQ of less than 2,200 was associated with an increased risk of pulmonary complications and mortality.

Use of Preoperative Autologous Blood Donation in Liver Resections for Colorectal Metastases

BACKGROUND Transfusion of allogeneic blood is associated with risks of human immunodeficiency virus and hepatitis transmission, transfusion reactions, and other potential immunologic and infectious complications. To determine if predonation of autologous blood impacts upon transfusion practice and clinical outcome following liver resection, clinical records of 379 consecutive patients undergoing hepatic resection for metastases of colorectal cancer were identified from the prospective hepatobiliary database and reviewed. METHODS Of the 379 hepatic resections performed for colorectal metastases between January 1991 and January 1996, 240 (63%) were hepatic lobectomy or trisegmentectomy. Thirty-two percent of patients (123 of 379) agreed to preoperative blood donation (POBD), and their clinical characteristics including age, preoperative hemoglobin, and operative mortality were comparable with those of patients without POBD. Liver resections were carried out using standard vascular inflow and outflow control. Parenchymal transections were performed bluntly with maintenance of low central venous pressure (0 to 5 cm H2O). No vascular isolation or normovolemic hemodilution was used intraoperatively. All erythrocyte transfusions during the entire hospital stay were considered and compared between the two groups. RESULTS Forty-five percent of patients (172 of 379) received blood transfusions during or after liver resections, of which 61% (105 of 172) required only 1 or 2 units. Only 17% of the POBD group required allogeneic blood. This was significantly less than the group without POBD (43%, P <0.01). There was no significant difference in the operative mortality (2.3% versus 4.9%, P = 0.2) and the median survival (50 versus 40 months, P = 0.3). CONCLUSIONS Major hepatic resections using current surgical techniques can be performed safely with low blood loss and transfusion is required for only a minority of patients. POBD further reduces transfusion requirement.

Renal function after low central venous pressure-assisted liver resection: assessment of 2116 cases.

OBJECTIVES Low central venous pressure (LCVP)-assisted hepatectomy is associated with decreased blood loss and lower transfusion rates. Concerns about its impact on renal function have prevented widespread application. This study was conducted to review the dynamics of renal function after LCVP-assisted hepatectomy. METHODS A retrospective analysis of a prospective surgical database was carried out. Estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease (MDRD) equation. The RIFLE (risk-injury-failure-loss-end-stage) criteria were used to define postoperative biochemical acute kidney injury (bAKI). Occurrences of clinically relevant AKI (cAKI) were identified in the study center postoperative database. RESULTS During the period 2003-2012, 2116 LCVP-assisted hepatectomies were performed. The median patient age was 61 years [interquartile range (IQR): 51-70 years] and 51% of patients were male. The median number of resected segments was two; resections involved from one to four segments. Median estimated blood loss was 300 ml (IQR: 200-600 ml). Rates of morbidity and 90-day mortality were 21% and 2%, respectively. Low baseline eGFR (<90 ml/min) was seen in 84% of patients; 29% of patients had eGFR of <30 ml/min. Postoperative bAKI was seen in 17% (n = 350) of patients. Biochemical AKI with low eGFR was seen in 336 patients, representing 16% of the whole cohort; 13% of patients had been at risk, 2% experienced injury and 1% experienced failure. Kidney function had normalized at discharge in 159 of these patients. Nine patients (<1%) developed postoperative cAKI. CONCLUSIONS The majority of patients in the study cohort had low baseline eGFR. Biochemical alterations in eGFR are transient in the vast majority of patients after LCVP-assisted hepatectomy and their clinical impact is limited. The present data suggest that clinically relevant renal dysfunction is a very uncommon event in patients undergoing LCVP-assisted liver resection.

Intraoperative administration of the intravenous angiotensin-converting enzyme inhibitor, enalaprilat, in a patient with congestive heart failure

Patients with heart failure due to coronary artery disease can be managed by afterload reduction as long as myocardial oxygen consumption is not increased by tachycardia and coronary artery perfusion pressure is not compromised. Recently, angiotensinconverting enzyme (ACE) inhibitors have been introduced for this purpose, and the active form of the ACE inhibitor enalapril, enalaprilat, is now available in intravenous (IV) form. This report describes the intraoperative management of a patient with a history of heart failure and coronary occlusive disease who benefited dramatically from enalaprilat, as documented by both thermister-tipped pulmonary artery catheter monitoring and two-dimensional transesophageal echocardiography enhanced with color flow Doppler.

Flow triggering added to pressure support ventilation improves comfort and reduces work of breathing in mechanically ventilated patients

PURPOSE The purpose of this study was to measure the effect of flow triggering (FT), added to pressure support ventilation (PSV), during spontaneous breathing in intubated patients. MATERIALS AND METHODS A prospective observational study was conducted at a Comprehensive Cancer Center, University Hospital. Fourteen consecutive critically ill, mechanically ventilated patients on PSV with positive end-expiratory pressure were studied. Flow triggering was added to PSV in spontaneously breathing ventilated patients. RESULTS Respiratory rate (f), minute ventilation (Vepsilon), patient work of breathing (WOBp), respiratory drive (P0.1), rapid shallow breathing index (f/Vt), tidal volume (Vt) and a visual analog scale of breathing effort and comfort all improved. There was a large decrease in WOBp and P0.1 when flow triggering was added to PSV (P<.001). There was a moderate decrease in f/V1 during the same procedure (P<.01). Twelve patients felt subjectively better with the intervention. CONCLUSIONS Flow triggering offers an excellent complement to PSV because it improves patient comfort and reduces the magnitude of the inspiratory effort as well as the delay time between inspiratory muscle contraction and gas flow. It augments gas exchange at no metabolic cost to the patient while reducing the work of breathing.

Body Mass Index as a Predictor of Complications and Length of Hospital Stay after Thoracic Surgery

Background: Body mass index (BMI) has been correlated to complications and outcome in surgical patients at the two extremes of the nutrition spectrum. Objective: To study the relationship between BMI, outcome, hospital length of stay and complications in oncology patients undergoing thoracic surgery. Design: The study population was divided according to BMI in normal weight patients (BMI = 18 to 25) and ovenveight patients (BMI > 25) and prospectively followed postoperative cardiac complications, pulmonary complications, and death. Charts were reviewed for length of hospital stay. Results: One hundred thirty-seven patients were studied. There were a total of 53 complications in 39 of 137 patients (BMI 26 ± 4). Thirty-five (25%) were pulmonary and 18 (13%) were cardiac complications. There was no correlation between BMI and either cardiac, pulmonary or all complications. Ovenveight patients spent an average of 6.8 ± 0.4 days and 20.5 ± 5.3 days if they had a complication, which was 8.0 ± 3.0 days more than...

Predicting Postoperative Outcome

Pulmonary complications are the main source of postop erative morbidity and mortality, with respiratory failure and pneumonia resulting in 50% of postoperative deaths after lung surgery. Despite the high incidence of postop erative complications, pulmonary resection remains the only effective treatment for lung cancer. Substantial resources are ascribed for the perioperative care of these high-risk patients. Clinical experience would dic tate that predicting outcome could be of immense value in allocating resources. This review will consider the predictive value of preoperative testing, including spi rometry, split lung function, blood gas analysis, carbon monoxide diffusion capacity, pulmonary vascular resis tance, and exercise testing, as well as recent efforts to develop a combined cardiopulmonary index.