Anesthesia for Liver Transplantation

The provision of anesthesia for a liver transplant program requires a dedicated team of anesthesiologists. Liver transplant anesthesiologists must have an understanding of liver physiology and anatomy; the spectrum of clinical disease associated with liver dysfunction; the impact of warm and cold ischemia times, surgical techniques in liver transplantation, and the impact of ischemia-reperfusion syndrome; and optimal practices to protect the liver. The team must provide a 24-hour service, be actively involved in the selection committee process, and stay current with advances in the subspecialty.

Continuous Noninvasive Hemoglobin Monitoring: A Measured Response to a Critical Review

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Published ahead of print March 5, 2015

Evaluating and monitoring sedation, arousal, and agitation in the ICU

Optimal management of patient comfort and sedative drug therapy for intensive care unit (ICU) patients includes establishing a goal of therapy-often defined by a desired level of consciousness, with titration of medications to achieve this target. An assessment of the level of consciousness is best performed using a simple tool, such as a sedation scale that relies on observation of the patient to assign a level of conscious that ranges from alert to unarousable. Many sedation scales incorporate observation of the patient's response to stimulation, which typically escalates from simply calling the patient's name to physical stimulation. Many such tools also incorporate an assessment of the presence and intensity of agitated behavior. Implementation of sedation scales has been associated with improved outcomes, and the frequent assessment of level of consciousness using a sedation scale is strongly recommended in clinical practice guidelines. Further, selection of a sedation scale that has been demonstrated to be valid and reliable in your patient population is endorsed. Objective measures of consciousness, such as devices that use processed electroencephalography, are less well established for routine ICU management and are recommended only for selected situations.

Clinical practice guidelines for the management of pain, agitation, and delirium in adult patients in the Intensive Care Unit: executive summary

OBJECTIVE

To revise the "Clinical Practice Guidelines for the Sustained Use of Sedatives and Analgesics in the Critically Ill Adult" published in Critical Care Medicine in 2002.

METHODS

The American College of Critical Care Medicine assembled a 20-person, multidisciplinary, multi-institutional task force with expertise in guideline development, pain, agitation and sedation, delirium management, and associated outcomes in adult critically ill patients. The task force, divided into four subcommittees, collaborated over six years in person, via teleconferences, and via electronic communication. Subcommittees were responsible for developing relevant clinical questions, using the Grading of Recommendations Assessment, Development and Evaluation method (www.gradeworkinggroup.org) to review, evaluate, and summarize the literature, and to develop clinical statements (descriptive) and recommendations (actionable). With the help of a professional librarian and Refworks database software, they developed a Web-based electronic database of over 19,000 references extracted from eight clinical search engines, related to pain and analgesia, agitation and sedation, delirium, and related clinical outcomes in adult ICU patients. The group also used psychometric analyses to evaluate and compare pain, agitation/sedation, and delirium assessment tools. All task force members were allowed to review the literature supporting each statement and recommendation and provided feedback to the subcommittees. Group consensus was achieved for all statements and recommendations using the nominal group technique and the modified Delphi method, with anonymous voting by all task force members using E-Survey (www.esurvey.com). All voting was completed in December 2010. Relevant studies published after this date and prior to publication of these guidelines were referenced in the text. The quality of evidence for each statement and recommendation was ranked as high (A), moderate (B), or low/very low (C). The strength of recommendations was ranked as strong (1) or weak (2) and either in favor of (+) or against (-) an intervention. A strong recommendation (either for or against) indicated that the intervention's desirable effects either clearly outweighed its undesirable effects (risks, burdens, and costs) or it did not. For all strong recommendations, the phrase "We recommend..." is used throughout. A weak recommendation, either for or against an intervention, indicated that the tradeoff between desirable and undesirable effects was less clear. For all weak recommendations, the phrase "We suggest..." is used throughout. In the absence of sufficient evidence, or when group consensus could not be achieved, no recommendation (0) was made. Consensus based on expert opinion was not used as a substitute for a lack of evidence. A consistent method for addressing potential conflicts of interest was followed if task force members were coauthors of related research. The development of this guideline was independent of any industry funding.

CONCLUSION

These guidelines provide a roadmap for developing integrated, evidence-based, and patient-centered protocols for preventing and treating pain, agitation, and delirium in critically ill patients.

Effect of inhibitors on glycoprotein biosynthesis and bacterial adhesion

Group B streptococci adhere to influenza-virus infected canine kidney epithelial cells but not to uninfected cells. For studies of the molecular nature of this interaction the bacteria were radiolabelled and a quantitative binding assay was developed with which the following properties of the system were observed. (1) Adhesion was specific for group B streptococci (GBS); streptococci from other serological groups did not bind and did not inhibit adhesion of radioactive GBS. (2) Binding of GBS to infected kidney cells was inhibited by the addition of cell walls from GBS to the kidney cell monolayers. (3) Preincubation of GBS with free influenza virus prevented their attachment to infected kidney cell monolayers. With a centrifugation type of assay, labelled influenza virus bound to GBS. This binding could be inhibited by several glycoproteins after removal of the terminal sialic acid. Asialo-glycopeptides of the complex type, isolated from these inhibitory glycoproteins, also bound to GBS. The influenza viral glycoproteins have been partially characterized and shown to contain a glycosylamine type of complex oligosaccharide. This type of oligosaccharide is biosynthesized by means of lipid-linked saccharide intermediates. Several antibiotics such as tunicamycin and streptovirudin, and other inhibitors such as 2-deoxyglucose and glucosamine, inhibit this lipid-linked pathway. These inhibitors also prevent the formation of mature influenza virus as well as the adherence of group B streptococci. Other inhibitors of protein glycosylation should be valuable as tools for improving further our understanding of the mechanism of cell adhesion.

Rapid sequence induction and intubation with 1 mg/kg rocuronium bromide in cesarean section, comparison with suxamethonium

OBJECTIVE

To demonstrate that Rocuronium Bromide can be used for rapid sequence induction in emergency conditions.

METHODS

Our study was performed between December 2005 and May 2006 in Jordan University Hospital, Jordan. We studied the efficacy and intubating conditions after administrating of Rocuronium Bromide 1 mg/kg at 60 second in group of 60 pregnant women undergoing elective or emergency cesarean section and compared the results with those obtained after giving Suxamethonium 1 mg/kg at 60 seconds in a group of patients similar to the Rocuronium group.

RESULTS

Intubating conditions after 1 mg /kg of Rocuronium Bromide were found to be acceptable (good and excellent) in 95% of patients and were similar to the Suxamethonium group (97%). The endotracheal tube could be passed through the vocal cards of all patients enrolled in the study.

CONCLUSION

Rocuronium Bromide 1 mg/kg can be safely used for rapid sequence induction in cesarean section and the intubating conditions are similar to those of Suxamethonium.

Seasonal changes in testicular size and serum LH, prolactin and testosterone concentrations in male polar bears (Ursus maritimus)

Little is known about the reproductive endocrinology of the male polar bear, Ursus maritimus, except that serum testosterone concentrations are high in April and May during the mating season and are low from August to November during the non-mating season. The objective of this study was to describe the relationship between seasonal changes in testicular size and serum concentrations of testosterone, LH and prolactin. Blood samples and testicular measurements were obtained from free-ranging male polar bears in Canada in April (n = 5) and May (n = 15) near Resolute Bay, Northwest Territories and near Churchill, Manitoba in July (n = 15) and October (n = 22). Testis size was greater in May (39.4 +/- 3.5 cm(2)) than in October (27.3 +/- 2.0 cm(2)) (P = 0.002). Serum testosterone concentrations were approximately three-fold higher in April (5.8 +/- 0.8 ng ml(-1)) than in May (1.7 +/- 0.5 ng ml(-1)), July (0.6 +/- 0.2 ng ml(-1)) and October (1.1 +/- 0.2 ng ml(-1)). Similarly, serum LH concentrations were high in April (0.14 +/- 0.04 ng ml(-1)) and low in May (0.09 +/- 0.01 ng ml(-1)), July (0.10 +/- 0.02 ng ml(-1)) and October (0.08 +/- 0.00 ng ml(-1)). Serum prolactin concentrations were high in April (1.9 +/- 0.3 ng ml(-1)), highest in May (2.5 +/- 0.2 ng ml(-1)), lower in July (1.3 +/- 0.1 ng ml(-1)) and lowest in October (0.8 +/- 0.07 ng ml(-1)). The present study demonstrates a positive relationship between testicular size and serum concentrations of LH, prolactin and testosterone in the male polar bear and confirms the previously reported seasonal changes in serum testosterone concentrations. Data from the present study provide important baseline and comparative endocrine information that can be used to aid captive breeding programmes in zoos and to further ecological-behavioural studies of polar bears.

Body burdens and tissue concentrations of organochlorines in polar bears (Ursus maritimus) vary during seasonal fasts

Lipophilic organochlorines (OCs) are ingested by mammals through their foods and are generally stored in adipose tissue depots. For some species, such as polar bears, the size of these depots can fluctuate seasonally by several-fold. However, the effect of these fluctuations on the fate of stored OCs in an animal with such labile lipid depots is unknown. We determined the whole body burden and tissue concentrations of OCs in free-ranging polar bears categorized by age (cubs-of-the-year, yearlings and adults) and sex before and after a fast averaging 56 days. Adipose tissue, plasma, and milk samples were analysed for sum of chlorobenzenes (sigma-ClBzs), hexachlorocyclohexanes (sigma-HCHs), chlordanes (sigma-CHLORs), dichlorodiphenyltrichloroethane compounds (sigma-DDTs) and polychlorinated biphenyls (sigma-PCBs). Decline in body mass during fasting ranged from 0.2 kg/day for cubs-of-the-year to 0.9 kg/day for sub-adult and adult males. Although all bears showed a decline in both lipid and lean mass during fasting, patterns of OC whole body burden changes were not consistent among compounds and bear classes. The burdens of sigma-DDTs declined by 11-50% for most bears during fasting, those of sigma-CHLORs declined by 67% during fasting in sub-adult and adult males but remained constant for all females, indicating male-specific metabolism of sigma-CHLORs. As fat depots became depleted, OC concentrations in the remaining adipose tissue varied; sigma-DDTs and sigma-HCHs declined while those of sigma-CHLORs and sigma-PCBs generally increased. Thus. within a 3-4 month fast, most polar bears were able to significantly rid their adipose tissue of sigma-DDTs and sigma-HCHs. Burdens of sigma-CHLORs (except males), sigma-ClBzs and sigma-PCBs remained constant for all classes of bears, therefore there was no significant excretion or metabolism during the fast of the specific congeners in these compound classes typically found in polar bears. The ratio of plasma/adipose tissue and milk/adipose tissue OC concentrations was the same for before and after the fast indicating that OC concentrations in polar bears are probably at a steady state among various body compartments. Concentrations of sigma-CHLORs and sigma-PCBs in milk almost doubled during the fast. As a consequence of this rise in milk OC concentrations, the whole body concentrations of these compounds increased in nursing cubs. Since developing young may be susceptible to the effects of environmental contaminants, the increased exposure of nursing cubs to OCs during a fast by their mothers is noteworthy.

Use of stable-carbon and -nitrogen isotopes to assess weaning and fasting in female polar bears and their cubs

In some species, stable-isotope techniques can provide insights into dietary regimens where there are temporal shifts in trophic level or feeding frequency. We determined stable carbon (δ13C) and nitrogen (δ15N) isotope values for plasma and milk proteins and δ13C values for milk lipids from female polar bears (Ursus maritimus) and cubs to (i) ascertain whether cubs are at a higher trophic level than their mothers as a result of nursing and whether we can determine when weaning occurs, and (ii) determine the impact of seasonal fasting on δ13C and δ15N values. The plasma δ13C values for mothers and cubs were similar to milk-protein δ13C values and were significantly enriched in 13C compared with those for milk lipid. Plasma from cubs of the year (COYs) in spring, when milk was their only diet, was isotopically enriched in 15N by 1.0‰ over that of their mothers (δ15N = 21.5 ± 0.8‰ (mean ± SD) for cubs and 20.5 ± 0.5‰ for mothers) and depleted in 13C by 0.8 ‰ (δ13C = –19.6 ± 0.5‰ for cubs and –18.8 ± 0.8‰ for mothers). For bears who fasted between summer and fall (3–4 months), plasma became depleted in 13C by 0.5‰ and in 15N by 1‰. Plasma from females, who had fasted from summer to spring (7–8 months) and given birth to cubs, became enriched in 13C by 0.7‰ and in 15N by 2‰. By using stable-isotope analyses we were able to show that (i) young cubs were at a higher trophic level than their mother when milk was their only food source, and (ii) seasonal fasting influenced δ13C and δ15N values. However, we were not able to use stable-isotope analyses to determine the exact time of weaning.

Readmission to the intensive care unit after liver transplantation

OBJECTIVE

We 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.

DESIGN

A retrospective review of a prospectively maintained liver transplant research database followed by a retrospective review of (a subgroup) patient charts and contemporaneous controls.

SETTING

A large metropolitan tertiary care center and adult liver transplant center.

PATIENTS

A total of 1,197 consecutive adult patients who underwent their initial liver transplantation from 1984 to 1996.

INTERVENTION

Readmission to the intensive care unit after adult liver transplantation and discharge from that unit.

MAIN RESULTS

Only 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.

CONCLUSIONS

We 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.

Pharmacokinetics and tissue residues of Telazol in free-ranging polar bears

A pharmacokinetic and tissue residue study was conducted to assess the risks associated with human consumption of polar bears in arctic Canada that have been exposed to the immobilizing drug Telazol, a mixture of tiletamine hydrochloride and zolazepam hydrochloride. Twenty-two bears were remotely injected with about 10 mg/kg of Telazol. Following immobilization, serum samples were collected serially at regular intervals until the bears awakened. Sixteen of the bears were relocated and killed under permit by local hunters at various times from 0.5 to 11 days after dosing. Serum, kidney, muscle and adipose tissue samples were collected immediately after death. All samples were stored at -70 C until analysis by HPLC. The concentration-time data of tiletamine and zolazepam in serum during the immobilization period were fitted to curves by computer and the pharmacokinetic parameters assessed. In addition, the serum and tissue samples collected at the time of death were analyzed for both parent drugs, for one metabolite of tiletamine (CI-398), and for three metabolites of zolazepam (metabolites 1, 2 and 4). A one-compartment model with first-order absorption and elimination best fit the time-series data for the drugs in serum during the immobilization period. This model gave half-lives (mean +/- SE) for tiletamine and zolazepam of 1.8+/-0.2 h and 1.2+/-0.08 h, respectively, clearance values of 2.1+/-0.3 l x h(-1) x kg(-1) and 1.1+/-0.1 l x h(-1) x kg(-1), and volumes of distribution of 5.2+/-0.6 l/kg and 1.8+/-0.2 l/kg. The concentrations of both drugs and their metabolites declined rapidly to trace levels by 24 h post-dosing, although extremely low concentrations of some metabolites were encountered sporadically over the entire sampling period. In particular, zolazepam metabolite 2, remained detectable in fat and muscle tissue at the end of the study, 11 days after dosing. It was concluded that during immobilization, both tiletamine and zolazepam levels decline rapidly in a monoexponential fashion, and their pharmacokinetic parameters in polar bears are similar to those observed in other species. Tissue levels of the drugs and their metabolites declined sufficiently rapidly that individuals eating meat from exposed bears would be unlikely to experience pharmacological effects from the drugs. Nevertheless, slight exposure to the drugs and/or their metabolites might be possible for an indeterminate time after dosing.

Anesthesia of polar bears (Ursus maritimus) with zolazepam-tiletamine, medetomidine-ketamine, and medetomidine-zolazepam-tiletamine

A 1:1 combination (by weight) of zolazepam and tiletamine is the drug of choice for anesthetizing polar bears (Ursus maritimus), but recovery time is prolonged when additional doses are administered. Recoveries may last 24 hr and may threaten the health of the bears. We compared the anesthetic effects of zolazepam-tiletamine (ZT) with those of medetomidine-ketamine (MK) and medetomidine-zolazepam-tiletamine (MZT) in 93 free-ranging polar bears. The MZT combination was administered in smaller dose and volume, resulted in more rapid, safer, and more predictable induction, provided more reliable anesthesia, and was safely reversed with atipamezole. Frequent occurrence of sudden recoveries during anesthesia with MK limited our use of this combination. MK and MZT sometimes caused apnea and bradycardia initially and hyperthermia at increased ambient temperatures. Hypoxemia occurred transiently with all combinations. When anesthesia with ZT and MK exceeded 1 hr, frequent necessary top-up doses caused irregular physiologic function. ZT is recommended for short duration anesthesia (< or = 1 hr), but MZT is better for anesthesia of longer duration and under circumstances where reversibility is desirable.

Cardiopulmonary response of anesthetized polar bears to suspension by net and sling

Since 1995, at least three polar bears (Ursus maritimus) have died in the area of Churchill (Manitoba, Canada) as a direct result of being suspended in a net during helicopter-assisted translocations. To assess and improve methods of suspending anesthetized polar bears, we conducted a study during November 1997 to determine the cardiopulmonary responses of eight captive polar bears to suspension by net and by sling. Each bear was anesthetized on two occasions in which the sequence of activities followed and the type of data collected was identical, with only the method of suspension differing. Control data obtained from 11 captive polar bears during 1995-96 was included in the statistical analyses of cardiopulmonary data to help clearly differentiate the cardiopulmonary effects of suspension from those of drug metabolism. Suspending polar bears above the ground by net caused acute hypertension (e.g., 17 to 49% increase in mean arterial pressure), possibly as a result of increased venous return due to body compression. Increased arousal (e.g., head, tongue, and limb movement) also occurred consistently during net-suspension and suggested a stress response. Surprisingly, most suspended bears showed little change in blood gas values, but at least one bear became hypoxemic (i.e., PaO2 < 60 mm Hg) with each method of suspension. Because of the potential health risks of hypertension and hypoxemia, we recommend modifying the method by which polar bears are suspended with the goal of reducing body compression.

Chlorinated hydrocarbon contaminants in polar bears from eastern Russia, North America, Greenland, and Svalbard: biomonitoring of Arctic pollution

Adipose tissue samples from polar bears (Ursus maritimus) were obtained by necropsy or biopsy between the spring of 1989 to the spring of 1993 from Wrangel Island in Russia, most of the range of the bear in North America, eastern Greenland, and Svalbard. Samples were divided into 16 regions corresponding as much as possible to known stocks or management zones. Concentrations of dieldrin (DIEL), 4,4'-DDE (DDE), sum of 16 polychlorinated biphenyl congeners (sigma PCB), and sum of 11 chlordane-related compounds and metabolites (sigma CHL) were determined. In order to minimize the effect of age, only data for adults (320 bears age 5 years and older) was used to compare concentrations among regions. Concentrations of sigma PCB were 46% higher in adult males than females, and there was no significant trend with age. Concentrations of sigma CHL were 30% lower in adult males than females. Concentrations of sigma PCB, sigma CHL, and DDE in individual adult female bears were standardized to adult males using factors derived from the least-square means of each sex category, and geometric means of the standardized concentrations on a lipid weight basis were compared among regions. Median geometric mean standardized concentrations (lipid weight basis) and ranges among regions were as follows: sigma PCB, 5,942 (2,763-24,316) micrograms/kg; sigma CHL, 1,952 (727-4,632) micrograms/kg; DDE, 219 (52-560) micrograms/kg; DIEL, 157 (31-335) micrograms/kg. Geometric mean sigma PCB concentrations in bears from Svalbard, East Greenland, and the Arctic Ocean near Prince Patrick Island in Canada were similar (20,256-24,316 micrograms/kg) and significantly higher than most other areas. Atmospheric, oceanic, and ice transport, as well as ecological factors may contribute to these high concentrations of sigma PCB. sigma CHL was more uniformly distributed among regions than the other CHCs. Highest sigma CHL concentrations were found in southeastern Hudson Bay, which also had the highest DDE and DIEL concentrations. In general, concentrations of sigma CHL, DDE, and DIEL were higher in eastern than western regions, suggesting an influence of North American sources. Average sigma PCB concentrations in bears from the Canadian Arctic were similar to those in 1982-84, while average sigma CHL and DDE concentrations were 35-44% lower and DIEL was 90% lower. However, the significance of these temporal trends during the 1980s is not conclusive because of the problems of comparability of data.

Severe pulmonary hypertension and amelioration of hepatopulmonary syndrome after liver transplantation

A patient with end-stage liver disease as a result of alpha1-antitripsin deficiency presented for orthotopic liver transplantation. The liver cirrhosis was complicated by portal hypertension and hepatopulmonary syndrome resulting in varicosities and severe hypoxia (room air oxygen saturation 69%). After transplantation, the hepatopulmonary syndrome improved but, over the next 14 months, the patient developed severe pulmonary hypertension. Six years posttransplantation, his room air oxygen saturation was 95% with pulmonary artery pressures of 109 mm Hg systolic and 26 mm Hg diastolic (mean 55 mm Hg) and a pulmonary vascular resistance 688 dynes x sec x cm.

Oral transmucosal fentanyl citrate as an additional premedicant for adult cardiac surgery patients

OBJECTIVE

To investigate the efficacy of a combination of midazolam and oral transmucosal fentanyl citrate (OTFC) as a preoperative medication for adult cardiac surgery patients compared with the use of midazolam alone.

DESIGN

A randomized, prospective study.

SETTING

University teaching hospital.

PARTICIPANTS

Patients scheduled for elective coronary artery bypass surgery.

INTERVENTIONS

All patients were given 50 micrograms/kg of midazolam intramuscularly in their rooms. Group I received 300 micrograms of OTFC Oralet (Anesta Corp, Salt Lake City, UT) if they weighed less than 70 kg and 400 micrograms of OTFC Oralet if they weighed more than 70 kg. Group II received a placebo Oralet. A radial artery catheter, two internal jugular venous catheters, and a pulmonary artery catheter inserted through one of the internal jugular catheters were placed in each study patient. Fentanyl was administered intravenously as a rescue drug.

MEASUREMENTS AND MAIN RESULTS

Ninety percent of midazolam/OTFC patients reported feeling no pain during catheter placement, compared with 50% of midazolam/placebo patients. Fifty percent of the placebo group required fentanyl supplement of 50 micrograms intravenously because of complaints of pain, compared with 10% of the OTFC group. The midazolam/OTFC group scored approximately 20% better than the placebo group in the independent observer score of patient analgesia and the anesthesiologist rating for ease of invasive catheter placement. No myocardial ischemic events were noted in either group as determined by electrocardiogram. All patients found the Oralet mode of delivery very acceptable.

CONCLUSIONS

The OTFC Oralet provides effective analgesia and sedation when combined with midazolam for invasive catheter placement in adult cardiac surgery patients. The OTFC Oralet with its gradual onset lessens the possibility of overmedicating with fentanyl, and it offers a very acceptable mode of delivery for a preemptive analgesic.

Enzyme-linked lectinsorbent assay measures N-acetyl-D-glucosamine in matrix of biofilm produced by Staphylococcus epidermidis

An enzyme-linked lectinsorbent assay (ELLA) was developed for quantification of in situ biofilm produced by Staphylococcus epidermidis in polystyrene 96-well tissue culture plates with phosphatase-labeled wheat germ agglutinin (WGA) as a specific probe for the GlcNAcbeta-1,4n component of exocellular matrix material (EMM) that is responsible for intercellular adhesion and accumulation. The ELLA and the modified Christensen dye assay were used to test 13 laboratory strains of coagulase-negative staphylococci and 10 clinical isolates of S. epidermidis. Four biofilm-positive laboratory strains of S. epidermidis were positive by both tests, and six biofilm-negative strains were negative by both. One strain of S. hemolyticus was positive by the ELLA only. Two of the 10 clinical isolates of S. epidermidis were positive by both assays, two were negative by both, and the remaining were positive by the ELLA only. The ELLA was objective, reproducible, specific, sensitive, and useful for screening strains for their capacity to adhere to plastic, produce EMM, and form biofilm.

Severe pulmonary hypertension in liver transplant candidates

Advanced liver disease with portal hypertension may be associated with pulmonary hypertension. A review of 1,205 consecutive liver transplant patients was made to assess the incidence and severity of pulmonary hypertension in patients with end-stage liver disease. Postoperative data were reviewed to determine if outcome was influenced and, in patients with severe pulmonary hypertension, whether pulmonary hypertension was reversed after transplantation. The hemodynamic data of 5 patients who were found to have severe pulmonary hypertension before transplantation and did not receive transplants were also reviewed. The incidence of pulmonary hypertension in the patients who received transplants was 8.5% (n = 102; mean pulmonary artery pressure, > 25 mmHg). The incidence of mild pulmonary hypertension was 6.72% (n = 81; systolic pulmonary artery pressure, 30 to 44 mmHg); that of moderate pulmonary hypertension was 1.16% (n = 14; systolic pulmonary artery pressure, 45 to 59 mmHg); and that of severe pulmonary hypertension was 0.58% (n = 7; systolic pulmonary artery pressure, > 60 mmHg). Mild and moderate pulmonary hypertension did not influence the outcome of the procedure. Severe pulmonary hypertension was associated with mortality rates of 42% at 9 months posttransplantation and 71% at 36 months posttransplantation. Only 2 of 7 patients with severe pulmonary hypertension have survived liver transplantation with a good quality of life. The remaining 5 patients continued to deteriorate with progressive right heart failure with no evidence of amelioration of the pulmonary hypertension. This experience supports the view that in most patients who have severe pulmonary hypertension associated with advanced liver disease, it is caused by fixed pathological changes in the pulmonary vasculature, is not reversible with liver transplantation, and is associated with a very high perioperative mortality rate.

Continuous small-dose tranexamic acid reduces fibrinolysis but not transfusion requirements during orthotopic liver transplantation

Tranexamic acid (TA) is a synthetic drug that inhibits fibrinolysis. It has been administered to decrease the use of blood products during cardiac surgery and orthotopic liver transplantation when infused in larger doses. A small-dose infusion of aprotinin causes a reduction in fibrinolysis and blood product requirement during orthotopic liver transplantation without apparent risk of intravascular thrombosis. This prospective study was designed to investigate whether a small-dose infusion of TA would be equally effective in reducing fibrinolysis and blood product transfusions during orthotopic liver transplantation. A double-blind, controlled study was undertaken to compare the efficacy of a small-dose TA infusion with that of a placebo. Thirty-two consecutive patients were randomized either to the TA group (n = 16), which received an intravenous infusion of 2 mg x kg(-1) x h(-1), or to the control group (n = 16), which received an identical volume of normal saline. Coagulation values were measured, a field rating was made by the surgeon, and a thromboelastogram was produced at four predetermined intervals throughout the case-before TA infusion was started, after portal vein ligation, 10 min after reperfusion, and at the end of surgery. Intraoperative transfusion requirements were recorded during the procedure and for the first 24 h postoperatively. A record was kept of any intraoperative epsilon-aminocaproic acid administered for uncontrolled fibrinolysis. The thromboelastogram clot lysis index was significant for lysis in the control group during both the anhepatic and the neohepatic phases (P < 0.01 and P < 0.05, respectively) when compared with the TA group. Fibrin degradation products were significantly increased (>20 microg/mL) in the control group at reperfusion (P < 0.03) and at the end of surgery (P < 0.01). D-dimers were also significantly increased (>1 mg/L) in the control group at the end of surgery (P < 0.04). Nine of the 16 control patients versus 3 of the 16 TA patients required epsilon-aminocaproic acid rescue for fibrinolysis. There were no other significant differences between groups. Transfusion requirements during surgery and for the first 24 h postoperatively did not differ significantly between the two groups. We conclude that the use of small-dose TA reduces fibrinolysis but not transfusion requirements during orthotopic liver transplantation.

Reversible immobilization of free-ranging polar bears with medetomidine-zolazepam-tiletamine and atipamezole

The objective of this study was to determine if the potent alpha 2 agonist, medetomidine, and its specific antagonist, atipamezole, could be effectively used to immobilize polar bears (Ursus maritimus). Specifically, our goal was to develop a drug combination containing medetomidine that addressed some of the problems such as prolonged recovery time, non-reversibility, and poor analgesia that have been identified with the currently preferred drug combination, zolazepamtiletamine (Telazol or Zoletil). During 1995 and 1996, 51 free-ranging polar bears along the western coast of Hudson Bay, Canada, were immobilized with a combination of medetomidine, zolazepam, and tiletamine (MZT). Immobilization with MZT was characterized by a short induction time, low volume, reliable and predictable immobilization and reversibility, adequate analgesia, and relative safety in handling for field personnel. Few adverse physiological effects were observed in any target animals with the exception of a single bear which convulsed and died shortly after it was reversed from anesthesia with atipamezole. We conclude that MZT is an effective drug combination for immobilizing polar bears. However, because of an unexplained mortality, further investigation of the physiological effects of MZT and atipamezole is warranted.

Pharmacokinetics of rocuronium during the three stages of liver transplantation

BACKGROUND

Little is known about the influence of liver transplantation on the pharmacokinetics of most anesthetic drugs. The authors determined the pharmacokinetics of rocuronium during liver transplantation and examined whether variability in pharmacokinetics could explain variability in recovery of neuromuscular function.

METHODS

Twenty patients undergoing liver transplantation were given rocuronium, 600 microg/kg, after induction of anesthesia and again after perfusion of the transplanted liver. Plasma was sampled to determine rocuronium concentrations. Pharmacokinetic models were fit to rocuronium concentrations versus time data using a mixed-effects population approach. Various models permitted changes in clearance (Cl) or central compartment volume to account for changes in hepatic function and circulatory status during the paleohepatic, anhepatic, and neohepatic periods. Time to initial recovery of four twitches of the orbicularis oculi was determined.

RESULTS

During the paleohepatic and anhepatic periods, the typical value of Cl was 2.47 ml x kg(-1) x min(-1) and was not influenced by the magnitude of preexisting liver disease (as evidenced by prothrombin time, bilirubin, serum albumin, alanine transaminase [ALT], and aspartate transaminase [AST]). During the neohepatic period, the typical value of Cl varied as a function of the duration of warm ischemia of the hepatic allograft and was 2.72 ml x kg(-1) x min(-1) for a patient with an average 60-min period of warm ischemia; time to neuromuscular recovery varied as a function of Cl.

CONCLUSIONS

Despite prolonged hypothermic ischemia, the newly transplanted liver eliminates rocuronium as well as the diseased native liver (and comparably with historical control values). However, some patients had decreased rocuronium Cl during the neohepatic period, apparently a result of prolonged graft warm ischemia. The authors' finding of preservation of hepatic drug elimination in the hepatic allograft is consistent with limited data for other drugs evaluated during anesthesia.

Hemodynamic changes during laparoscopic cholecystectomy in patients with severe cardiac disease

STUDY OBJECTIVE

To evaluate the hemodynamic changes and need for pharmacologic interventions during laparoscopic cholecystectomy in patients with severe cardiac dysfunction.

DESIGN

Prospective open study.

SETTING

University hospital.

PATIENTS

17 ASA physical status III and IV patients with severe cardiac dysfunction undergoing elective laparoscopic cholecystectomy.

INTERVENTIONS

A standardized general anesthetic and surgical technique was used for all patients. In addition to routine monitoring, invasive hemodynamic monitoring included radial and pulmonary artery (PA) cannulation.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic parameters were recorded prior to induction of anesthesia, 5 minutes after induction of anesthesia but prior to incision, 5 minutes after carbon dioxide (CO2) insufflation and head-up tilt, every 10 minutes after change of position, after deflation of the abdomen and return to supine position, and 10 minutes after attaining supine position. Need for any pharmacologic interventions [to maintain mean arterial pressure (MAP) < 100 mmHg and/or systemic vascular resistance (SVR) < 2,000 dynes sec/cm-5, and/or cardiac index (CI) > 1.5 L/min/m2] and the incidence of any myocardial morbidity and mortality was noted. CI decreased significantly (p < 0.05) following insufflation and remained low until exsufflation. MAP, SVR, and PA occlusion pressure increased significantly (p < 0.05) after CO2 insufflation. Three of the 17 patients required administration of nitroglycerin to maintain the MAP and SVR within the accepted limits, one of whom also required administration of dobutamine to maintain CI. There was no myocardial morbidity or mortality in the perioperative period.

CONCLUSION

Laparoscopic cholecystectomy in patients with severe cardiac dysfunction results in significant hemodynamic changes.

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 immediate normal liver function. Group II contained 7 patients with primary dysfunctional livers. Primary dysfunction was determined by peak serum aspartate aminotransferase 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.

Nitric oxide does not reverse pulmonary hypertension associated with end-stage liver disease: a preliminary report

Pulmonary hypertension is a well known, though uncommon complication of end-stage liver disease (ESLD). Patients with severe pulmonary hypertension and ESLD undergoing orthotopic liver transplantation (OLT) may develop right ventricular failure and death. This study investigates the reversibility of pulmonary hypertension by the inhalation of nitric oxide in patients under evaluation for OLT. Ten patients with ESLD who were discovered to have moderate to severe pulmonary hypertension were administered nitric oxide via face mask in concentrations ranging from 0 to 80 ppm. Inhaled nitric oxide is a potent pulmonary vasodilator without apparent systemic effects. Nitric oxide had no demonstrable effect on mean pulmonary artery pressure (PAP) (37 vs. 37 mm Hg), transpulmonary gradient (TPG) (26 vs. 26 mm Hg), or pulmonary vascular resistance (PVR) (295 vs. 288 dynes x sec x cm (-5)). Two patients were discovered to have an elevated pulmonary artery occlusion pressure (PAOP) on baseline readings. The cause of pulmonary hypertension in these two patients was secondary to volume overload as a result of hepato-renal syndrome rather than primary pulmonary arteriolar pathology and was responsive to diuresis or dialysis but not to nitric oxide therapy. In conclusion nitric oxide does not reverse pulmonary hypertension associated with ESLD.