Michael Ramsay

Postreperfusion syndrome during liver transplantation for cirrhosis: Outcome and predictors

During orthotopic liver transplantation (OLT), a marked decrease in blood pressure following unclamping of the portal vein and liver reperfusion is frequently observed and is termed postreperfusion syndrome (PRS). The predictive factors and clinical consequences of PRS are not fully understood. The goal of this study was to identify predictors of PRS and morbidity/mortality associated with its occurrence during OLT in patients with cirrhosis. During a 3‐year period, all consecutive OLT procedures performed in patients with cirrhosis were studied. Exclusion criteria were OLT for acute liver failure, early retransplantation, combined liver/kidney transplantation, and living‐donor related transplantation. PRS was defined as a decrease in the mean arterial pressure of more than 30% of the value observed in the anhepatic stage, for more than 1 minute during the first 5 minutes after reperfusion of the graft. Transplantation was performed with preservation of the inferior vena cava with or without temporary portocaval shunt. Associations between PRS and donor and recipient demographic data, recipient operative and postoperative outcomes were tested with bivariate statistics. Independent predictors of PRS were determined in multivariable logistic regression analysis. Of the 75 patients included in the study, 20 patients (25%) developed PRS. In a multivariable analysis, absence of a portocaval shunt [odds ratio (95% confidence interval) = 4.42 (1.18‐17.6)] and duration of cold ischemia [odds ratio (95% confidence interval) = 1.34 (1.07‐1.72)] were independent predictors of PRS. Patients who experienced PRS displayed more postoperative renal failure and lower early (<15 days after OLT) survival (80% versus 96%; P = 0.04). In conclusion, the absence of portocaval shunt and the duration of cold ischemia were independent predictors of intraoperative PRS. PRS was associated with significant adverse postoperative outcome. These results provide realistic clinical targets to improve patient outcome after OLT for cirrhosis. Liver Transpl 15:522–529, 2009.

Readmission to the intensive care unit after liver transplantation

ObjectiveWe undertook this study to understand the factors at our transplant center that contribute to patients’ return to the ICU after their liver transplant and their initial discharge from that unit. Patients who, after liver transplantation, fail discharge from the Intensive Care Unit (ICU) and must be readmitted to that unit may well utilize many more resources than those patients who are well enough to stay out of the ICU. DesignA retrospective review of a prospectively maintained liver transplant research database followed by a retrospective review of (a subgroup) patient charts and contemporaneous controls. SettingA large metropolitan tertiary care center and adult liver transplant center. PatientsA total of 1,197 consecutive adult patients who underwent their initial liver transplantation from 1984 to 1996. InterventionReadmission to the intensive care unit after adult liver transplantation and discharge from that unit. Main ResultsOnly recipient age, pretransplant synthetic function labs (protime and albumin), bilirubin levels, and intraoperative blood product requirements could be statistically linked to the group requiring ICU readmission. The primary etiology for ICU readmission was cardiopulmonary deterioration. Readmission was associated with significantly lower patient and graft survivals. A detailed review of 23 patients transplanted from October 1994 to June 1996 was made, with special emphasis on cardiopulmonary status (hemodynamics, respiratory variables, and chest radiograph findings). This subgroup was compared with 30 temporally matched controls who were not readmitted to the ICU. Intravascular fluid overload and lower inspiratory capacity were significant factors related to ICU readmission. Readmitted patients had a longer hospitalization with higher hospital charges than the control group. ConclusionsWe conclude that the most important means of preventing ICU readmission in liver transplantation patients is to optimize cardiopulmonary function and status. Close monitoring of fluid balance to avoid hypervolemia is essential. Readmitted patients have a greater resource utilization and have lower survival rates.

Duration of rocuronium-induced neuromuscular block during liver transplantation: A predictor of primary allograft function

The prolongation of vecuronium-induced neuromuscular block has been reported as a predictor of hepatic allograft dysfunction. This study investigates the duration of action of rocuronium, which also relies on hepatic clearance, to examine whether it also is prolonged with allograft dysfunction. Fifty-seven patients undergoing orthotopic liver transplant were given rocuronium (0.6 mg/kg) prior to allograft placement and the recovery of contraction of the orbicularis oculi muscle to a 2-Hz train-of-four stimulus was recorded. Fifteen minutes after reperfusion of the allograft, rocuronium (0.6 mg/kg) was administered and the time to recovery of muscle contraction to a train-of-four stimulus (train-of-four time) was again recorded. The patients were divided into two groups according to posttransplant liver function. Group I consisted of 50 patients with immedite normal liver function. Group II contained 7 patients with primary dysfunctional livers. Primary dysfunction was determined by peak serum aspartate amino-transferase and alanine aminotransferase levels > 2000 U/L, and prothrombin time > 16 s. The train-of-four time in Group II was prolonged compared with Group I (P < 0.05). Immediate graft function testing using the recovery time from rocuronium of > 150 min has a positive predictive value of 100% and a negative predictive value of 96%. The sensitivity and specificity is 71% and 100%, respectively. Receiver operating characteristic analysis supports this conclusion. (Anesth Analg 1997;84:870-4)

Role of microdialysis catheters in clinical decision making: bench to bedside?

The microdialysis technique was introduced experimentally in animal studies in the 1970s to determine the concentrations of low-molecular-weight compounds in the interstitial fluid of the brain. The technique was used in humans in the 1980s to assess the status of tissues into which they had been inserted before changes in blood or plasma levels could be noted. The technique is based on the passive diffusion of substances according to their concentration gradients from the extracellular fluid to the dialysate. The catheter has a tubular, semipermeable dialysis membrane and has a function very similar to the passive function of a capillary blood membrane. The catheter is perfused with an electrolyte solution such as normal saline. The perfusate is chosen to allow the diffusion of selected substances so that equilibration takes place with surrounding tissues. In this way, microdialysis provides continuous monitoring of metabolic changes in tissues. Larger pore catheters may require the addition of albumin or dextran to the solution to prevent fluid loss into tissues. The size of the pores in the catheter determines how large the molecules to be measured can be. The smaller pores (20 kDa) can measure glucose, glycerol, pyruvate, and lactate, and the larger pores (100 kDa) can measure inflammatory cytokines and some drugs. This is opening the door to studying drug levels directly at the level of the drug target and to not relying on plasma concentrations to determine the pharmacodynamic and pharmacokinetic profiles of a therapeutic agent. This may enhance the management of immunosuppressant drug therapy in the future through the measurement of the drug concentration at the effector site. This unique technology can also be used to measure target site concentrations of antibiotics or anticancer drugs in different tissues and organs and lead to more effective dosing or delivery systems. Experimental catheters have been made with up to a 3000-kDa cutoff for measuring even larger molecules. The limitations of microdialysis catheters include the effect of local tissue trauma occurring during placement, but this has been shown to clear after 30 minutes of perfusion. The probes are usually perfused with aqueous solutions such as Ringer’s solution, so they are conceptually limited to the study of hydrophilic molecules. Continuous microdialysis measurements of metabolic changes in the interstitial space offer the opportunity for the earlier detection of adverse changes in an organ before reflections in the peripheral blood or any clinical symptoms develop. Cerebral microdialysis is being used clinically in patients with traumatic brain injury as a unique source of pathological changes at a molecular level in the brain. Cerebral ischemia is being detected early through the measurement of lactate/pyruvate ratios in the dialysate. The viability of microvascular flaps, especially when direct visualization is difficult, can be determined by continuous microdialysis monitoring. In liver transplantation, major complications that present early include preservation injury, acute rejection, and ischemia. The differential diagnosis rests on clinical suspicion, nonspecific clinical symptoms, and laboratory abnormalities such as elevations of serum aminotransferase, alkaline phosphatase, and bilirubin levels, but these values are nonspecific and do not correlate with the severity of rejection. Despite close posttransplant follow-up for enzyme elevations and intermittent ultrasound Doppler screening of blood flow, hypoperfusion may not be detected early, and this can result in preventable organ failure. Acute rejection occurs in approximately 20% to 40% of recipients, and the gold standard for confirmation is liver biopsy. This

System engineering approach to documentation

Documentation processes are an indispensible part of patient care. Timely access to complete and accurate documentation is crucial to patient safety. However, there is no sufficient tool to help health care professionals effectively manage documentation processes. In this study, we developed an evaluation methodology, including a documentation matrix, a documentation process flow diagram, and a document value tool, to analyze the necessity and redundancy of the documentation processes. We applied this methodology in a gastrointestinal lab and improved the transparency of the documentation processes among providers.