Randomized comparison of sevoflurane versus propofol to reduce perioperative myocardial ischemia in patients undergoing noncardiac surgery.

BACKGROUND: Volatile anesthetics provide myocardial preconditioning in coronary surgery patients. We hypothesized that sevoflurane compared with propofol reduces the incidence of myocardial ischemia in patients undergoing major noncardiac surgery. METHODS AND RESULTS: We enrolled 385 patients at cardiovascular risk in 3 centers. Patients were randomized to maintenance of anesthesia with sevoflurane or propofol. We recorded continuous ECG for 48 hours perioperatively, measured troponin T and N-terminal prohormone of brain natriuretic peptide (NT-proBNP) on postoperative days 1 and 2, and evaluated postoperative delirium by the Confusion Assessment Method. At 6 and 12 months, we contacted patients by telephone to assess major adverse cardiac events. The primary end point was a composite of myocardial ischemia detected by continuous ECG and/or troponin elevation. Additional end points were postoperative NT-proBNP concentrations, major adverse cardiac events, and delirium. Patients and outcome assessors were blinded. We tested dichotomous end points by χ(2) test and NT-proBNP by Mann-Whitney test on an intention-to-treat basis. Myocardial ischemia occurred in 75 patients (40.8%) in the sevoflurane and 81 (40.3%) in the propofol group (relative risk, 1.01; 95% confidence interval, 0.78-1.30). NT-proBNP release did not differ across allocation on postoperative day 1 or 2. Within 12 months, 14 patients (7.6%) suffered a major adverse cardiac event after sevoflurane and 17 (8.5%) after propofol (relative risk, 0.90; 95% confidence interval, 0.44-1.83). The incidence of delirium did not differ (11.4% versus 14.4%; P=0.379). CONCLUSIONS: Compared with propofol, sevoflurane did not reduce the incidence of myocardial ischemia in high-risk patients undergoing major noncardiac surgery. The sevoflurane and propofol groups did not differ in postoperative NT-proBNP release, major adverse cardiac events at 1 year, or delirium.

Aortic cross-clamping and reperfusion in pigs reduces microvascular oxygenation by altered systemic and regional blood flow distribution.

BACKGROUND: In this study, we tested the hypothesis that aortic cross-clamping (ACC) and reperfusion cause distributive alterations of oxygenation and perfusion in the microcirculation of the gut and kidneys despite normal systemic hemodynamics and oxygenation. METHODS: Fifteen anesthetized pigs were randomized between an ACC group (n = 10), undergoing 45 minutes of aortic clamping above the superior mesenteric artery, and a time-matched sham surgery control group (n = 5). Systemic, intestinal, and renal hemodynamics and oxygenation variables were monitored during 4 hours of reperfusion. Microvascular oxygen partial pressure (microPo(2)) was measured in the intestinal serosa and mucosa and the renal cortex, using the Pd-porphyrin phosphorescence technique. Intestinal luminal Pco(2) was determined by air tonometry and the serosal microvascular flow by orthogonal polarization spectral imaging. RESULTS: Organ blood flow and renal and intestinal microPo(2) decreased significantly during ACC, whereas the intestinal oxygen extraction and Pco(2) gap increased. The intestinal response to reperfusion after ACC was a sustained reactive hyperemia but no such effect was seen in the kidney. Despite a sustained high intestinal O(2) delivery, serosal microPo(2) (median [range], 49 mm Hg [41-67 mm Hg] versus 37 mm Hg [27-41 mm Hg]; P < 0.05 baseline versus 4 hours reperfusion) and the absolute number of perfused microvessels decreased along with an increased intestinal Pco(2) gap (17 mm Hg [10-19 mm Hg] versus 23 mm Hg [19-30 mm Hg]; P < 0.05). In contrast, the kidney showed a progressive O(2) delivery decrease accompanied by a decrease in renal cortex oxygenation (70 mm Hg [52-93 mm Hg] versus 57 mm Hg [33-64 mm Hg]; P < 0.05). CONCLUSION: Increased systemic and regional blood flow and oxygen supply after ACC does not ensure adequate regional blood flow and microcirculatory oxygenation in all organs.

[Preoperative evaluation of patients with endocrine diseases]. / Präoperative Vorbereitung von Patienten mit endokrinologischen Erkrankungen.

Patients with endocrine diseases are candidates for an early anaesthesiologic evaluation. This is especially important for diseases with a high potential for preoperative optimization of therapeutic options, as diabetes, morbid obesity and thyroid dysfunction. For rare diseases, early anaesthesiologic evaluation allows the anaesthetic team to gather specific information, which is not available on an overnight basis.

A preoperative single dose of methadone for moderate-to-severely painful surgery reduces postoperative morphine consumption.

BACKGROUND: Data from patient questionnaires reveal that the intensity of postoperative pain is widely underestimated. Insufficient pain control may contribute to impaired short- and long-term outcome. Preoperative administration of methadone might potentially improve postoperative pain control due to its long pharmacological half-life. METHODS: The aim of this study was to evaluate the effect of a single dose of methadone administered at anesthesia induction on postoperative analgesic requirements in ASA I-III patients after moderate-to-severely painful surgery scheduled for ≥90 minutes. Patients were randomized to receive either a single dose of methadone (0.2 mg/kg) or fentanyl (standard, 0.003 mg/kg) intravenously (IV) at anesthesia induction. For postoperative pain control, all study patients were accommodated with morphine on the basis of patient-controlled analgesia (PCA). RESULTS: Per-protocol analysis revealed that the median cumulative morphine consumption was significantly lower in patients receiving a single dose of methadone, in the Postanesthesia Care Unit (0 mg vs. 7 mg of morphine, P<0.01) and during the first 72 hours after surgery (19 mg vs. 35 mg of morphine, P<0.05 for all days). Fentanyl consumption during surgery (0.25 mg [0.1-0.425 mg] in the study group vs. 0.3 mg [0.15-0.45 mg] in the control group, P=0.4499) was comparable among groups. Median pain scores at rest and in motion, and patient satisfaction were also similar in both groups (95.7% vs. 89.3% of patients were satisfied in the study and control group, respectively) during follow-up on postoperative days 1-3. CONCLUSIONS: A single dose of methadone administered at anesthesia induction prior to moderate-to-severely painful surgery is a possible strategy to reduce postoperative morphine consumption.

Inducible nitric oxide synthase inhibition improves intestinal microcirculatory oxygenation and CO2 balance during endotoxemia in pigs.

OBJECTIVE: We examined whether selective inhibition of inducible nitric oxide synthase (iNOS) promotes intestinal microvascular oxygenation (microPO2) and CO2 off-load after endotoxic shock. DESIGN AND SETTING: Prospective, controlled experimental study in a university animal research laboratory. SUBJECTS: 13 domestic pigs. INTERVENTIONS: After baseline measurements shock was induced by 1 microg kg-1 h-1 endotoxin until mean arterial pressure fell below 60 mmHg. After 30 min in shock the animals were resuscitated with either fluid alone (control, n=6) or fluid and the iNOS inhibitor N-[3-(aminomethyl)benzyl]acetamidine hydrochloride (1400W, n=7). As final experimental intervention all animals received the nonselective NOS inhibitor L-NAME. MEASUREMENTS AND RESULTS: Systemic and regional hemodynamic and oxygenation parameters were measured at baseline, during endotoxemia and shock, hourly for 3 h of 1400W therapy, and 30 min after the final L-NAME administration. microPO2 was assessed by the Pd-porphyrin phosphorescence technique, and the arterial to intestinal PCO2 gap was determined by air tonometry. Endotoxemia and shock resulted in a decrease in ileal mucosal and serosal microPO2 and a rise in PCO2 gap. The combination of 1400W and fluid resuscitation, but not fluid alone, normalized both the serosal microPO2 and the intestinal PCO2 gap. Administration of L-NAME decreased cardiac output and oxygen delivery and intestinal microPO2 and blood flow in both groups. CONCLUSIONS: Partial blockade of NO production by 1400W increased serosal microvascular oxygenation and decreased the intestinal CO2 gap. This findings are consistent with the idea that 1400W corrects pathological flow distribution and regional dysoxia within the intestinal wall following endotoxic shock.

Influence of dobutamine on the variables of systemic haemodynamics, metabolism, and intestinal perfusion after cardiopulmonary resuscitation in the rat.

BACKGROUND: Global left ventricular dysfunction after successful resuscitation from cardiac arrest may be treated successfully with dobutamine but the effects on intestinal perfusion are unknown. METHODS: In 24 male Sprague-Dawley rats ventricular fibrillation was induced. After 4 min of untreated cardiac arrest, precordial chest compression was performed for 4 min; adrenaline (epinephrine) (90 microg kg(-1)) was injected, followed by defibrillation. Return of spontaneous circulation was achieved in 18 animals, which were allocated to receive saline 0.9% (control group, n = 6), dobutamine at 5 microg kg(-1) min(-1) (n = 6) or dobutamine at 10 microg kg(-1) min(-1) (n = 6). Measurements of haemodynamic variables and intestinal tonometer P(CO2) were made before induction of ventricular fibrillation and 15, 30, 60, and 120 min postresuscitation. RESULTS: At 120 min postresuscitation, mean aortic pressure was 82 +/- 20, 104 +/- 19, and 113 +/- 15 mmHg for the control group, the dobutamine (5 microg kg(-1) min(-1)) group and the dobutamine (10 microg kg(-1) min(-1)) group (P < 0.05 for comparison of the dobutamine (10 microg kg(-1) min(-1)) group versus the control group). Respective abdominal aortic blood flow was 107 +/- 16, 133 +/- 49, and 145 +/- 18 ml min(-1) kg(-1) (P < 0.05 for comparison of the dobutamine (10 microg kg(-1) min(-1)) group versus the control group), and superior mesenteric artery blood flow was 25 +/- 9, 28 +/- 8, and 33 +/- 8 ml min(-1) kg(-1). Arterial lactate was significantly higher (P < 0.05) in the control group (2.3 +/- 0.6 mmol l(-1)) than in the dobutamine (5 microg kg(-1) min(-1)) group (1.6 +/- 0.3 mmol l(-1)) and dobutamine (10 microg kg(-1) min(-1)) group (1.5 +/- 0.3 mmol l(-1)). Tonometrically derived P(CO2) gap was highly elevated at 15 min of postresuscitation and returned to prearrest level at 120 min postresuscitation in all groups. CONCLUSIONS: Dobutamine enhances the recovery of global haemodynamic and metabolic variables early after cardiac arrest.

Resuscitation from cardiac arrest with adrenaline/epinephrine or vasopressin: effects on intestinal mucosal tonometer pCO(2) during the postresuscitation period in rats.

BACKGROUND: The use of vasopressin instead of adrenaline/epinephrine during resuscitation improves vital organ perfusion, but the effects on mesenteric perfusion following successful resuscitation are not fully evaluated. The present study was designed to compare the effects of vasopressin and adrenaline/epinephrine, given to rats during resuscitation from ventricular fibrillation, on to mesenteric ischaemia, as determined by intestinal mucosal tonometer pCO(2) during the postresuscitation period. METHODS AND RESULTS: Male Sprague-Dawley rats (n=28) were allocated randomly to receive vasopressin (0.8 U/kg) or adrenaline/epinephrine (90 microg/kg) after 5 min of ventricular fibrillation. Precordial chest compression was initiated 4 min after the start of ventricular fibrillation, continued for 4 min, and followed by defibrillation. Seven of 14 (vasopressin) and 12 of 14 (adrenaline/epinephrine) rats were successfully defibrillated (P=0.10, Fisher's exact test) and observed for 60 min. Intestinal mucosal tonometer pCO(2) measurements before cardiac arrest and 15, 30, and 60 min following return of spontaneous circulation were 47+/-3, 73+/-8, 63+/-7, and 56+/-6 mmHg in the vasopressin group and 48+/-5, 78+/-7, 67+/-6, and 62+/-6 mmHg in the adrenaline/epinephrine group (P<0.05 at 60 min between vasopressin and adrenaline/epinephrine). Right atrial hemoglobin oxygen saturations at these time points were 73+/-5, 51+/-12, 58+/-11, and 63+/-5% in the vasopressin group and 76+/-7, 44+/-10, 52+/-10 and 54+/-8% in the adrenaline/epinephrine group (P<0.05 at 60 min between vasopressin and adrenaline/epinephrine). CONCLUSIONS: We conclude that in this rat model the administration of vasopressin instead of adrenaline/epinephrine for CPR tends to be associated with lower resuscitation success, but less mesenteric ischaemia during the postresuscitation period in successfully resuscitated rats.

Anaphylaxis to isosulfan blue and cross-reactivity to patent blue V: case report and review of the nomenclature of vital blue dyes.

BACKGROUND: Blue dyes used for lymphatic mapping in sentinel lymph node biopsy cause intraoperative anaphylactic reactions in up to 2.7% of patients. With increasing implementation of this technique, the incidence of anaphylaxis to these dyes can be expected to increase. In the literature, the chemically often unrelated and inconsistently designated dyes have been confused, adding to other inconsistencies in the nomenclature. OBJECTIVE: To demonstrate the nomenclature, chemical and physiologic differences, and allergenicity of the various blue dyes used in a medical context. METHODS: We describe a patient with an intraoperative grade IV anaphylactic reaction to isosulfan blue. Immediate-type hypersensitivity was proved by positive skin test reactions and CD63 expression to isosulfan blue and cross-reactivity to patent blue V. RESULTS: A review of the literature clarified the exact nomenclature of the blue dyes and the possible pitfalls of confusing nomenclature in the context of structurally closely related dyes with different allergenic properties. For the detection of type I hypersensitivity, intracutaneous tests are valuable tools. An IgE-mediated mechanism has been shown recently. In most cases, sensitization exists without known previous exposure in a medical context. This may be due to the widespread use of such dyes in objects of everyday life. Preoperative antiallergic medication use does not prevent anaphylactic reactions but apparently reduces their severity. CONCLUSION: For better comparison and precision, the Chemical Abstracts Service number of the respective dye should always be given.

Rocuronium versus succinylcholine for rapid sequence induction of anesthesia and endotracheal intubation: a prospective, randomized trial in emergent cases.

When anesthesia is induced with propofol in elective cases, endotracheal intubation conditions are not different between succinylcholine and rocuronium approximately 60 s after the injection of the neuromuscular relaxant. In the present study, we investigated whether, in emergent cases, endotracheal intubation conditions obtained at the actual moment of intubation under succinylcholine differ from those obtained 60 s after the injection of rocuronium. One-hundred-eighty adult patients requiring rapid sequence induction of anesthesia for emergent surgery received propofol (1.5 mg/kg) and either rocuronium (0.6 mg/kg; endotracheal intubation 60 s after injection) or succinylcholine (1 mg/kg; endotracheal intubation as soon as possible). The time from beginning of the induction until completion of the intubation was shorter after the administration of succinylcholine than after rocuronium (median time 95 s versus 130 s; P < 0.0001). Endotracheal intubation conditions, rated with a 9-point scale, were better after succinylcholine administration than after rocuronium (8.6 +/- 1.1 versus 8.0 +/- 1.5; P < 0.001). There was no significant difference in patients with poor intubation conditions (7 versus 12) or in patients with failed first intubation attempt (4 versus 5) between the groups. We conclude that during rapid sequence induction of anesthesia in emergent cases, succinylcholine allows for a more rapid endotracheal intubation sequence and creates superior intubation conditions compared with rocuronium.

0.5% versus 1.0% 2-chloroprocaine for intravenous regional anesthesia: a prospective, randomized, double-blind trial.

UNLABELLED: In this randomized prospective double-blind study we tested the hypothesis that compared with 40 mL chloroprocaine 0.5%, 40 mL chloroprocaine 1% results in an earlier onset to analgesia duration and improves distal tourniquet tolerance in 150 patients undergoing forearm surgery under IV regional anesthesia using a double-cuff technique, switching from the proximal to the distal cuff was performed if pain scores increased above 4 of 10. Switching to the distal cuff resulted in pain scores below 4 in 69% of patients in the 0.5% group and in 88% of patients in the 1% group (P = 0.047). In addition, both groups differed in the sustained effect on distal tourniquet pain (P = 0.020). Time between injection and onset to analgesia duration was 13 +/- 1 min in the 0.5% group and 11 +/- 1 min in the 1% group (P = 0.0006). On release of the tourniquet, signs of systemic local anesthetic toxicity occurred in 6 patients of the 0.5% group and 28 of the 1% group (P < 0.0001). We conclude that chloroprocaine 1% resulted in an earlier onset of analgesia and improved distal tourniquet tolerance. However, these beneficial effects must be weighed against a fourfold increase in side effects. IMPLICATIONS: Compared to a standard dose of 40 mL 0.5% chloroprocaine, 40 mL 1% chloroprocaine resulted in an earlier onset of analgesia duration and improved distal tourniquet tolerance during IV regional anesthesia. These beneficial effects must be weighed against a fourfold increase in signs of systemic local anesthetic toxicity.

Ileocecal valve as substitute for the missing pyloric sphincter after partial distal gastrectomy.

OBJECTIVES: Accelerated gastric emptying (including dumping syndrome) occurs frequently after gastric resections, largely resulting from rapid entry of meal contents into the small intestine. The authors hypothesized that an ileocecal segment used as an interpositional graft placed between the remaining part of the stomach and the small intestine would slow down food transit and thus replace pyloric function. METHODS: Thirty Göttingen minipigs were randomized into three groups. Group 1: partial gastrectomy and Roux-en-Y reconstruction; Group 2: partial gastrectomy and ileocecal interpositional graft; and Group 3: sham laparotomy. Gastric emptying in the nonsedated animals was quantified using radioscintigraphy at 3 and 6 months postoperatively. The animals ingested 300 grams of soft food containing 99mTc labeled resin- pellets using a technique previously described. Data were analyzed using ANOVA. RESULTS: Three months postoperatively, the ileocecal group had a significantly prolonged gastric emptying time compared with the Roux-en-Y group, but gastric emptying time was also significantly faster compared to the control group (sham laparotomy). After 6 months no significant difference was seen between the ileocecal group and the controls, while emptying rates were still significantly faster in the Roux-en-Y group. CONCLUSIONS: Reconstruction of the gastric reservoir with an ileocecal segment largely restores gastric emptying patterns of food in minipigs. Six months postoperatively, gastric emptying time is similar to that of controls, and significantly slower when compared with the group with Roux-en-Y reconstruction. These results suggest that the ileocecal interposition graft could offer specific advantages over current reconstruction procedures.