Prolonged Catheter Use and Infection in Regional Anesthesia: A Retrospective Registry Analysis.

BACKGROUND: Prolonged catheter use is controversial because of the risk of catheter-related infection, but the extent to which the risk increases over time remains unknown. We thus assessed the time-dependence of catheter-related infection risk up to 15 days. METHODS: Our analysis was based on the German Network for Regional Anesthesia, which includes 25 centers. We considered 44,555 patients who had surgery between 2007 and 2014 and had continuous regional anesthesia as well as complete covariable details. Cox regression analysis was performed and adjusted for confounding covariables to examine the relationship between catheter duration and probability of infection-free catheter use. RESULTS: After adjustment for confounding factors, the probability of infection-free catheter use decreases with each day of peripheral and epidural catheter use. In peripheral catheters, it was 99% at day 4 of catheter duration, 96% at day 7, and 73% at day 15. In epidural catheters, it was 99% at day 4 of catheter duration, 95% at day 7, and 73% at day 15. Only 31 patients (0.07%) had severe infections that prompted surgical intervention. Among these were five catheters that initially had only mild or moderate signs of infection and were left in situ; all progressed to severe infections. CONCLUSIONS: Infection risk in catheter use increases over time, especially after four days. Infected catheters should be removed as soon as practical. VISUAL ABSTRACT: An online visual overview is available for this article at http://links.lww.com/ALN/B683.

[Upper Age Limit in Outpatient Anesthesia: Opportunities and Risks]. / Obere Altersgrenze bei ambulanter Anästhesie: Möglichkeiten und Risiken.

Ambulatory surgery in elderly patients continues to increase - avoiding hospitalization and thus postoperative cognitive dysfunction in older patients being its major objectives. An upper age limit in outpatient anesthesia does not exist to date. However, functional rather than chronological age is crucial in patient selection. In consensus discussion, baseline functional status should be evaluated regularly - defined as everyday behaviors necessary to maintain daily life and encompassing areas of physical, cognitive, and social functioning. Moreover, frailty in elderly patients can be quantified objectively and is associated with increased perioperative morbidity in ambulatory general surgery. The decision for or against outpatient anesthesia therefore remains a case-by-case decision which should be discussed within a team.

Long-term continuous renal replacement therapy and anticoagulation with citrate in critically ill patients with severe liver dysfunction.

BACKGROUND: As of 2009, anticoagulation with citrate was standard practice in continuous renal replacement therapy (CRRT) for critically ill patients at the University Medical Centre of Saarland, Germany. Partial hepatic metabolism of citrate means accumulation may occur during CRRT in critically ill patients with impaired liver function. The aim of this study was to evaluate the actual influence of hepatic function on citrate-associated complications during long-term CRRT. METHODS: In a retrospective study conducted between January 2009 and November 2012, all cases of dialysis therapy performed in the interdisciplinary surgical intensive care unit were analysed. Inclusion criteria were CRRT and regional anticoagulation with citrate, pronounced liver dysfunction, and pathologically reduced indocyanine green plasma disappearance rate (ICG-PDR). RESULTS: A total of 1339 CRRTs were performed in 69 critically ill patients with liver failure. At admission, the mean Model for End-stage Liver Disease score was 19.2, and the mean ICG-PDR was 9.8%. Eight patients were treated with liver replacement therapy, and 30 underwent transplants. The mortality rate was 40%. The mean duration of dialysis was 19.4 days, and the circuit patency was 62.2 h. Accumulation of citrate was detected indirectly by total serum calcium/ionised serum calcium (tCa/iCa) ratio > 2.4. This was noted in 16 patients (23.2%). Dialysis had not to be discontinued for metabolic disorder or accumulation of citrate in any case. In 26% of cases, metabolic alkalosis occurred with pH > 7.5. Interestingly, no correlation between citrate accumulation and liver function parameters was detected. Moreover, most standard laboratory liver function parameters showed poor predictive capabilities for accumulation of citrate. CONCLUSIONS: Our findings indicate that extra-hepatic metabolism of citrate seems to exist, avoiding in most cases citrate accumulation in critically ill patients despite impaired liver function. Because the citric acid cycle is oxygen-dependent, disturbed microcirculation would result in inadequate citrate metabolism. Raising the tCa/iCa ratio would therefore be an indicator of severity of illness and mortality rather than of liver failure. However, further studies are warranted for confirmation.

Single-dose Antibiotic Prophylaxis in Regional Anesthesia: A Retrospective Registry Analysis.

BACKGROUND: Catheter-related infection is a serious complication of continuous regional anesthesia. The authors tested the hypothesis that single-dose antibiotic prophylaxis is associated with a lower incidence of catheter-related infections. METHODS: Our analysis was based on cases in the 25-center German Network for Regional Anesthesia database recorded between 2007 and 2014. Forty thousand three hundred sixty-two surgical patients who had continuous regional anesthesia were grouped into no antibiotic prophylaxis (n = 15,965) and single-dose antibiotic prophylaxis (n = 24,397). Catheter-related infections in each group were compared with chi-square test after 1:1 propensity-score matching. Odds ratios (ORs [95% CI]) were calculated with logistic regression and adjusted for imbalanced variables (standardized difference more than 0.1). RESULTS: Propensity matching successfully paired 11,307 patients with single-dose antibiotic prophylaxis (46% of 24,397 patients) and with 11,307 controls (71% of 15,965 patients). For peripheral catheters, the incidence without antibiotics (2.4%) was greater than with antibiotic prophylaxis (1.1%, P < 0.001; adjusted OR, 2.02; 95% CI, 1.49 to 2.75, P < 0.001). Infections of epidural catheters were also more common without antibiotics (5.2%) than with antibiotics (3.1%, P < 0.001; adjusted OR, 1.94; 95% CI, 1.55 to 2.43, P < 0.001). CONCLUSIONS: Single-dose antibiotic prophylaxis was associated with fewer peripheral and epidural catheter infections.

Awake, sedated or anaesthetised for regional anaesthesia block placements?: A retrospective registry analysis of acute complications and patient satisfaction in adults.

BACKGROUND: Whether adults should be awake, sedated or anaesthetised during establishment of regional anaesthesia is still debated and there is little information on the relative safety of each. In paediatric practice, there is often little choice but to use sedation or anaesthesia as otherwise the procedures would be too distressing and patient movement would be hazardous. OBJECTIVE(S): The objective of this study was to evaluate complications related to central and peripheral regional block and patient satisfaction in awake, sedated and anaesthetised adult patients. DESIGN: A retrospective registry analysis. SETTING: The German Network of Regional Anaesthesia database was analysed between 2007 and 2012. PATIENTS: We included data of 42 654 patients and defined three groups: group I awake (n = 25 004), group II sedated (n = 15 121) and group III anaesthetised (n = 2529) for block placement. MAIN OUTCOME MEASURES: Odds ratios [OR; 95% confidence interval (CI)] were calculated with logistic regression analysis and adjusted for relevant confounders to determine the risk of block-related complications in sedated or anaesthetised patients compared with awake patients. RESULTS: Rates of local anaesthetic systemic toxicity were comparable between the groups [awake 0.02% (95% CI: 0.002 to 0.0375), sedated 0.02% (0.003 to 0.042) and anaesthetised 0% (0 to 0.12%)], as were the rates of pneumothorax [awake 0.035% (0 to 0.074), sedated 0% (0 to 0.002) and anaesthetised 0.2% (0 to 0.56)]. Considering peripheral nerve blocks, sedated patients had a decreased risk for multiple skin puncture [adjusted OR: 0.78 (95% CI: 0.71 to 0.85), premature termination [0.45 (0.22 to 0.91)], primary failure [0.58 (0.40 to 0.83)] and postoperative paraesthesia [0.35 (0.28 to 0.45)], but an increased risk for a bloody tap [1.82 (1.50 to 2.21)]. General anaesthesia increased the risk of a bloody tap [adjusted OR: 1.33 (95% CI: 1.01 to 1.78)] and multiple skin puncture [1.28 (1.12 to 1.46)], but decreased the risk for postoperative paraesthesia [0.16 (0.06 to 0.38)]. In neuraxial sites, sedation increased the risk for multiple skin puncture [adjusted OR: 1.18 (95% CI: 1.09 to 1.29)], whereas block placement under general anaesthesia decreased the risk for multiple skin puncture [0.53 (0.39 to 0.72)] and bloody tap but significantly increased the risk for postoperative paraesthesia related to a catheter [2.45 (1.19 to 5.02)]. Sedation was associated with a significant improvement in patient satisfaction. CONCLUSION: Sedation may improve safety and success of peripheral nerve block placement. Block placement under general anaesthesia in adults should be reserved for experienced anaesthesiologists and special situations.

Simplified determination of commissural orientation in bicuspid aortic valves.

OBJECTIVES: In bicuspid aortic valves (BAV), commissural orientation (CO) varies between 180° and close to 120°. Postoperative CO has a strong effect on repair durability, and different repair approaches have been proposed according to CO; it is thus important for aortic repair. A precise, simple and reproducible determination by preoperative echocardiography would facilitate intraoperative decision-making. We compared 4 different methods of determination of CO in BAV. METHODS: Preoperative transoesophageal echocardiograms of 62 patients with BAV were analysed. CO was measured using either the coaptation centre or the geometric centre of the root. The geometric centre of the root was determined through approximation using a circle or an ellipse, or the midpoint of a line between the centre of the non-fused and the fused sinuses. RESULTS: The 3 different geometric methods led to almost identical results (interclass coefficient 0.98-0.99), with the line segment being the easiest to use. The use of the coaptation centre was associated with the underestimation of commissural angle of up to 30° compared to the geometric centre; the discrepancy was significant and most pronounced for asymmetric BAV (140-160°; P = 0.005). CONCLUSIONS: CO can reproducibly be determined using a line segment between the centre of the non-fused and fused sinuses. The use of the coaptation centre can lead to misleading results, in particular in asymmetric BAVs.

Bilateral papillary muscle repositioning: successful repair of functional mitral regurgitation in dilative cardiomyopathy.

OBJECTIVES: Functional mitral regurgitation (FMR) in patients with non-ischaemic dilative cardiomyopathy (DCM) is associated with heart failure and poor outcome. Aggressively undersized annuloplasty as an annular solution for a ventricular problem ameliorates heart failure but may be associated with recurrent FMR and does not improve survival. We sought to analyse if moderately undersized annuloplasty with repositioning of both papillary muscles can lead to improved valve stability and outcome in patients with DCM and FMR. METHODS: In 66 patients with DCM-associated FMR (age 66 ± 12 years, ejection fraction 29 ± 6% and mean pulmonary artery pressure 35 ± 11 mmHg) and severe leaflet tethering (tenting height ≥10 mm) bilateral papillary muscle repositioning was added to moderately undersized ring annuloplasty (median size 30 mm). Concomitant surgery included tricuspid valve repair in 86% of patients and atrial ablation in 44%. RESULTS: The early mortality rate was 9%. Overall 5-year freedom from all-cause death, left ventricular assist device implantation or heart transplant was 58% (95% confidence interval 45-71%). Six patients underwent reoperation (redo repair n = 4). Reverse remodelling was observed during follow-up in 66% of patients with decreasing left ventricular end-diastolic diameters (66 ± 5 to 61 ± 12 mm; P < 0.001) and left ventricular end-systolic diameters (56 ± 9 to 51 ± 14 mm; P = 0.001). Subgroup analyses (partial versus complete ring, preoperative left ventricular end-diastolic diameters <65 mm vs left ventricular end-diastolic diameter ≥65 mm) documented similar survival rates. A competing risks regression analysis identified cerebral vascular disease (P = 0.01), use of a partial ring (P = 0.03) and absence of tricuspid valve repair (P = 0.03) as independent predictors of death. CONCLUSIONS: The combination of bilateral papillary muscle repositioning and moderately undersized ring annuloplasty leads to stable mid-term repair results and reverse remodelling in patients with DCM and FMR and severe leaflet tethering.

Plasma Disappearance Rate of Indocyanine Green for Determination of Liver Function in Three Different Models of Shock.

The measurement of the liver function via the plasma disappearance rate of indocyanine green (PDRICG) is a sensitive bed-side tool in critical care. Yet, recent evidence has questioned the value of this method for hyperdynamic conditions. To evaluate this technique in different hemodynamic settings, we analyzed the PDRICG and corresponding pharmacokinetic models after endotoxemia or hemorrhagic shock in rats. Male anesthetized Sprague-Dawley rats underwent hemorrhage (mean arterial pressure 35 ± 5 mmHg, 90 min) and 2 h of reperfusion, or lipopolysaccharide (LPS) induced moderate or severe (1.0 vs. 10 mg/kg) endotoxemia for 6 h (each n = 6). Afterwards, PDRICG was measured, and pharmacokinetic models were analyzed using nonlinear mixed effects modeling (NONMEM®). Hemorrhagic shock resulted in a significant decrease of PDRICG, compared with sham controls, and a corresponding attenuation of the calculated ICG clearance in 1- and 2-compartment models, with the same log-likelihood. The induction of severe, but not moderate endotoxemia, led to a significant reduction of PDRICG. The calculated ICG blood clearance was reduced in 1-compartment models for both septic conditions. 2-compartment models performed with a significantly better log likelihood, and the calculated clearance of ICG did not correspond well with PDRICG in both LPS groups. 3-compartment models did not improve the log likelihood in any experiment. These results demonstrate that PDRICG correlates well with ICG clearance in 1- and 2-compartment models after hemorrhage. In endotoxemia, best described by a 2-compartment model, PDRICG may not truly reflect the ICG clearance.

Cusp Nadir Relocation by Root Remodeling in Unicuspid Aortic Valve Repair.

We describe a root remodeling technique for the unicuspid and unicommissural aortic valve with a moderately hypoplastic anterior commissure. This technique achieves symmetric bicuspidization without patch insertion to cusps. Partial cusp fusion of the anterior commissure is divided, and two symmetric tongues of a Dacron graft are sutured to each center of cusp insertion lines. The cusp nadirs are relocated posteriorly, and the bicuspidized valve has two sufficiently high commissures from a new angulated virtual basal ring. To optimize valve configuration, annuloplasty and prolapse correction according to effective height concept are added. This technique is a promising option in select patients.

Early and long-term outcomes for patients undergoing reoperative aortic root replacement.

OBJECTIVES: There are limited data on aortic root replacement (ARR) in patients with previous cardiac surgery. We analysed short-term and long-term results for patients with ARR after previous cardiac surgery. METHODS: From September 1995 to April 2015, 130 patients underwent reoperative ARR. Fifty patients had undergone ARR previously (Group I), and 80 had been treated by isolated aortic valve repair or replacement (Group II). The primary indications for surgery were active endocarditis in 65 patients (50%), aneurysmatic root dilatation in another 37 (28.5%) and valve failure in 27 (20.8%). RESULTS: Overall hospital mortality was 10% (n = 13). Survival at 10 and 15 years was 59.4% and 40.6%, respectively. Survival at 10 and 15 years was 71.5% and 62.5% in Group I and 56.2% and 35.4% in Group II, respectively (P = 0.14). Survival was significantly worse in patients operated for active endocarditis (23.7% vs 56.4% at 15 years; P < 0.001). Inferior 15-year survival was also observed for patients requiring concomitant surgery for cardiac comorbidities (10.5% vs 48.7%; P = 0.003) and in the elderly (≥60 years; 26.8% vs 59.5%; P < 0.001). Ten-year survival was best in patients after valve-preserving root replacement (100%). Multivariable analysis revealed age, active endocarditis and concomitant surgery for cardiac comorbidities as risk factors for death. CONCLUSIONS: ARR after previous cardiac surgery can be performed with reasonable short-term and long-term survival. It is inferior in patients with active endocarditis or cardiac comorbidities and in the elderly. In these scenarios, less invasive procedures may be considered where applicable.

Hemin arginate-induced heme oxygenase 1 expression improves liver microcirculation and mediates an anti-inflammatory cytokine response after hemorrhagic shock.

Microvascular failure is a major determinant for the development of hepatocellular dysfunction after hemorrhagic shock. Induction of heme oxygenase (HO) 1 may confer hepatocellular protection. Hemin arginate (HAR) induces HO-1 and protects against shock-induced organ failure. The mechanisms are not completely understood, but HO-1-mediated protective effects on the microcirculation and on the inflammatory response may contribute. Therefore, the aim of the present study was to investigate the influence of HAR pretreatment on liver microcirculation and cytokine response to assess the role of HO-1-mediated effects under these conditions. Male Sprague-Dawley rats (200-300 g; n=8 per group) were subjected to hemorrhage (MAP, 30-40 mmHg for 1 h) 24 h after pretreatment with vehicle (Ringer solution) or HAR (5 mg kg(-1)), followed by 2 h of resuscitation. The microcirculation and the redox state (nicotinamide adenine dinucleotide phosphate [reduced form; NADPH] autofluorescence) of the liver were assessed using intravital microscopy. Cytokine levels (TNF-alpha and IL-10) were quantified using an enzyme-linked immunosorbent assay. A profound induction of HO-1 was observed 24 h after pretreatment with HAR. Hemorrhage significantly reduced sinusoidal perfusion and increased NADPH autofluorescence and cytokine levels. Hemin arginate pretreatment significantly improved liver microcirculation, reduced NADPH autofluorescence, significantly increased IL-10, and tended to decrease TNF-alpha serum levels compared with shock vehicle. Blockade of the HO pathway with tin-mesoporphyrin-IX after HAR pretreatment abolished the observed beneficial effects, whereas the additional administration of the carbon monoxide donor dichloromethane reversed the tin-mesoporphyrin-IX-mediated changes. These results suggest that HAR pretreatment improves liver microcirculation and mediates an anti-inflammatory cytokine response after hemorrhagic shock through induction of HO-1 and in part through an increased carbon monoxide release.

Psoas Versus Femoral Blocks: A Registry Analysis of Risks and Benefits.

BACKGROUND AND OBJECTIVES: Psoas blocks are an alternative to femoral nerve blocks and have the potential advantage of blocking the entire lumbar plexus. However, the psoas muscle is located deeply, making psoas blocks more difficult than femoral blocks. In contrast, while femoral blocks are generally easy to perform, the inguinal region is prone to infection. We thus tested the hypothesis that psoas blocks are associated with more insertion-related complications than femoral blocks but have fewer catheter-related infections. METHODS: We extracted 22,434 surgical cases from the German Network for Regional Anesthesia registry (2007-2014) and grouped cases as psoas (n = 7593) and femoral (n = 14,841) blocks. Insertion-related complications (including single-shot blocks and catheter) and infectious complications (including only catheter) in each group were compared with χ tests. The groups were compared with multivariable logistic models, adjusted for potential confounding factors. RESULTS: After adjustment for potential confounding factors, psoas blocks were associated with more complications than femoral blocks including vascular puncture 6.3% versus 1.1%, with an adjusted odds ratio (aOR) of 3.6 (95% confidence interval [CI], 2.9-4.6; P < 0.001), and multiple skin punctures 12.6% versus 7.7%, with an aOR of 2.6 (95% CI, 2.1-3.3; P <0.001). Psoas blocks were also associated with fewer catheter-related infections: 0.3% versus 0.9% (aOR of 0.4; 95% CI, 0.2-0.8; P = 0.016), and with improved patient satisfaction (mean ± SD 0- to 10-point scale score, 9.6 ± 1.2 vs 8.4 ± 2.9; P < 0.001). Results from a propensity-matched sensitivity analysis were similar. CONCLUSIONS: Psoas blocks are associated with more insertion-related complications but fewer infectious complications. CLINICAL TRIAL REGISTRATION: ID NCT02846610.

Reexamining remodeling.

OBJECTIVE: Root remodeling was proposed as valve-preserving root replacement to treat patients with aortic regurgitation and root aneurysm. The objective of this retrospective study was to review 18 years of experience with root remodeling and to identify predictors of valve durability. METHODS: Between October 1995 and December 2013, root remodeling was performed in 747 patients. The aortic valve anatomy was tricuspid in 431 patients, bicuspid in 290 patients, and unicuspid in 26 patients. Aortic aneurysm was present in 688 patients, and 59 procedures were performed for acute aortic dissection type A. The severity of aortic regurgitation ranged from grade 0 to IV (grade 0, 1%; grade 1, 8%; grade 2, 26%; grade 3, 62%; grade 4, 3%; median, 3). All patients underwent root remodeling, concomitant operations were performed in 352 patients, and cusp repair was used in 690 procedures. RESULTS: Hospital mortality was 2%. Overall freedom from reoperation was 92% at 10 years and 91% at 15 years. Overall freedom from reoperation was 95% for tricuspid valves at 10 and 15 years, 89% for bicuspid aortic valves at 10 years (P = .006), and 83% for bicuspid aortic valves at 15 years. By multivariate analysis, the strongest risk factors for failure were an aortoventricular junction 28 mm or greater (hazard ratio, 1.43) and the use of a pericardial patch as part of cusp repair (hazard ratio, 6.24). CONCLUSIONS: Root remodeling continues to be a viable option in valve-preserving root replacement. If combined with careful assessment and, if necessary, correction of aortic valve geometry, reproducible restoration of aortic valve function can be achieved with good long term durability.

Hemodynamic response to exercise as measured by the solar IKG impedance cardiography module and correlation with metabolic variables.

OBJECTIVE: Impedance Cardiography (ICG) has been shown to be a feasible and accurate method for non-invasive measurement of cardiac index (CI). Aim of this investigation was the correlation of hemodynamic variables under exercise as measured by a specific ICG-monitor (Solar IKG-Modul, Version 3.0, GE-Healthcare, Freiburg, Germany) with metabolic variables. METHODS: Ten healthy volunteers were included in the investigation doing ergometer exercise (5 min equilibration followed by 5 min each at 50, 75, 100 and 125 W). Hemodynamic parameters were obtained by ICG. Metabolic variables were assessed by indirect calorimetry with the Deltatrac II Metabolic monitor using a helmet system for spontaneous respiration. RESULTS: CI increased throughout exercise (baseline: 3.0 +/- 0.4 l/min/m(2); 125 W: 4.8 +/- 0.5 l/min/m(2)). Heart rate (baseline: 87.2 +/- 13.4 bpm; 125 W: 152.7 +/- 22.4 bpm) and contractility (velocity index) (baseline: 48.9 +/- 9.3/1000 s; 125 W: 70.5 +/- 10.0/1000 s) showed a continuous rise while the stroke index decreased after an initial rise (baseline: 35.0 +/- 4.6 ml/m(2); 50 W: 37.6 +/- 4.9 ml/m(2); 75 W: 41.2 +/- 5.9 ml/m(2); 125 W: 32.3 +/- 6.1 ml/m(2)). VO(2) (baseline: 335.2 +/- 84.1 ml/min; 125 W: 1298.9 +/- 282.3 ml/min) and VCO(2)(baseline: 255.4 +/- 74.5 ml/min; 125 W: 1342.5 +/- 282.5 ml/min) increased throughout exercise. There was a good correlation in the individual fits between hemodynamic and metabolic variables. CONCLUSION: CI in healthy volunteers, as measured by the Solar IKG-Modul, correlates well with O(2)-consumption and CO(2)-production in individual subjects, thus indicating the metabolic needs under exercise conditions in healthy individuals.

Dobutamine improves liver function after hemorrhagic shock through induction of heme oxygenase-1.

RATIONALE: Induction of heme oxygenase-1 (HO-1) protects the liver against reperfusion injury after hemorrhagic shock. Previous data suggest that the beta(1)-adrenoceptor agonist dobutamine induces HO-1 in hepatocytes. OBJECTIVES: To investigate the functional significance of dobutamine pretreatment for liver function after hemorrhagic shock in vivo. METHODS: Anesthetized rats received either Ringer's (Vehicle/Shock), 10 microg/kg/min of the beta(1)-adrenoceptor agonist dobutamine (Dob/Shock), or 10 microg/kg/min dobutamine and 500 microg/kg/min of the beta(1)-adrenoceptor antagonist esmolol (Dob/Esmolol/Shock) for 6 h. Hemorrhagic shock was induced thereafter (mean arterial pressure, 35 mm Hg for 90 min). Animals were resuscitated with shed blood and Ringer's. In addition, the HO pathway was blocked after dobutamine pretreatment with 10 micromol/kg tin-mesoporphyrin-IX (Dob/SnMP/Shock) or animals received 100 mg/kg of the carbon monoxide donor dichloromethane (DCM/Shock). MEASUREMENTS: Hepatocellular metabolism and liver blood flow were measured by plasma disappearance rate of indocyanine green (PDR(ICG)) as a sensitive marker of liver function. MAIN RESULTS: Pretreatment with dobutamine induced HO-1 in pericentral hepatocytes and improved PDR(ICG) (Vehicle/Shock: 11.7 +/- 8.12%/min vs. Dob/Shock: 19.7 +/- 2.46%/min, p = 0.006). Blockade of the HO pathway after preconditioning and the combined pretreatment with dobutamine and esmolol decreased PDR(ICG) (Dob/SnMP/Shock: 12.6 +/- 4.24%/min, p = 0.011; Dob/Esmolol/Shock: 10.2 +/- 4.34%/min, p = 0.008). Pretreatment with a carbon monoxide donor improved PDR(ICG) (DCM/Shock: 18 +/- 3.19%/min, p = 0.022) compared with Vehicle/Shock. CONCLUSIONS: These results suggest a beta(1)-adrenoceptor-dependent hepatic up-regulation of HO-1 and a better maintained hepatocellular function after hemorrhagic shock in animals pretreated with dobutamine. The improved hepatocellular function may be in part mediated by carbon monoxide because of up-regulation of HO-1. Pretreatment with dobutamine might be a potential means of pharmacologic preconditioning before ischemia-reperfusion of the liver.