Anaesthetic management of a patient with erythropoietic protoporphyria for ventricular septal defect closure.

Erythropoietic protoporphyria (EPP) is due to a deficiency in ferrochelatase required for haem synthesis. We describe the anaesthetic management of a seven-year-old with EPP undergoing closure of a haemodynamically significant ventricular septal defect. Photosensitivity in EPP patients is triggered at wavelengths near 400 nm and light-excited porphyrins generate free radicals and singlet oxygen that lead to erythrocyte deformity and haemolysis. Stimuli that could trigger a porphyric crisis during anaesthesia and surgery were reduced by avoiding exposure to the sensitive 400 nm spectrum and using light sources covered with yellow acrylate filters in the operating room. Anaesthetic agents not previously associated with porphyric crisis were chosen. Whole blood priming of the extracorporeal circuit was performed to ensure adequate haemoglobin concentrations during the perioperative period.

Intrathecal bupivacaine reduces pruritus and prolongs duration of fentanyl analgesia during labor: a prospective, randomized controlled trial.

UNLABELLED: Pruritus is a frequent complication (40%-100%) of intrathecal (IT) fentanyl 25 microg (F) for labor analgesia. The addition of IT bupivacaine 2.5 mg (B) to F has been reported in a nonrandomized series to have a 17.3% incidence of pruritus. This study prospectively evaluated the incidence and distribution of pruritus in laboring parturients receiving IT F + B. Sixty-five laboring parturients were randomly assigned to receive IT F, B, or F + B as part of a combined spinal-epidural technique. Visual analog scores, sensory level, motor strength, and pruritus were recorded before injection and at intervals thereafter. When present, the distribution of pruritus was evaluated. The duration of analgesia was determined as the time from IT drug administration until the patient requested supplemental analgesia. The median duration of analgesia in the F, B, and F + B groups was 62.5, 55.0, and 94.5 min, respectively. Compared with F alone, the combination of F + B led to a decreased frequency of pruritus (36.4% vs 95%). The incidence of facial pruritus (25%) was same in the F + B and F groups; however, the occurrence of pruritus distributed over the rest of the body was significantly more frequent in the F compared with the F + B group. The combination of F + B prolongs the duration of labor analgesia compared with IT F or B alone. F + B also leads to a decreased incidence of pruritus, except in the facial region. IMPLICATIONS: When administered intrathecally with fentanyl 25 microg in laboring parturients, bupivacaine 2.5 mg attenuates the frequency of pruritus on all parts of the body except the face. This combination also results in a rapid onset and prolonged duration of labor analgesia compared with either drug alone.

Pharmacokinetics of doxacurium during normothermic and hypothermic cardiopulmonary bypass surgery.

PURPOSE: To compare the pharmacokinetic behaviour of doxacurium in patients undergoing normothermic or hypothermic cardiopulmonary bypass (CPB) for coronary artery bypass graft surgery. METHODS: Twenty patients in two equal groups were studied. Anaesthesia was induced with sufentanil and midazolam after a standard premedication. Doxacurium was administered at 3 x ED95 (80 micrograms.kg-1), and anaesthesia was maintained with 0.5 microgram.kg-1 hr-1 sufentanil, 0.05 mg.kg-1 midazolam and isoflurane 0.5-1%. Systemic temperature for patients in the normothermic and hypothermic groups was maintained at 33-36 C and 26-30 C respectively. Timed blood and urine samples were collected and pharmacokinetic parameters were estimated using a non-compartmental approach. RESULTS: For the normothermic and hypothermic groups, terminal elimination half-life (t1/2 beta) was 100.1 +/- 28 and 183.8 +/- 60 min (P < 0.05) respectively, elimination half-life during the CPB phase (T1/2 CPB) 114.5 +/- 10 and 183.8 +/- 60 min (P < 0.05), mean residence time 108.8 +/- 25 and 164.8 +/- 34 min (P < 0.05) and apparent volume of distribution at steady state 0.20 +/- 0.03 and 0.26 +/- 0.04 L.kg-1 (P < 0.05). Compared with the hypothermic group, the normothermic group had a higher rate of renal clearance (1.40 +/- 0.4 vs 0.93 +/- 0.3 ml.min-1.kg-1; P < 0.05) and a higher value for renal clearance as a percentage of the total clearance (76.2 +/- 10 vs 58.3 +/- 20%). CONCLUSION: The elimination rate of doxacurium during normothermic CPB is faster than that in hypothermic CPB.

Early tracheal extubation after coronary artery bypass graft surgery reduces costs and improves resource use. A prospective, randomized, controlled trial.

BACKGROUND: Economics has caused the trend of early tracheal extubation after cardiac surgery, yet no prospective randomized study has directly validated that early tracheal extubation anesthetic management decreases costs when compared with late extubation after cardiac surgery. METHODS: This prospective, randomized, controlled clinical trial was designed to evaluate the cost savings of early (1-6 h) versus late tracheal extubation (12-22 h) in patients after coronary artery bypass graft (CABG) surgery. The total cost for the services provided for each patient was determined for both the early and late groups from hospital admission to discharge home. All costs applicable to each of the services were classified into direct variables, direct fixed costs, and overhead (an indirect cost). Physician fees and heart catheterization costs were included. The total service cost was the sum of unit workload and overhead costs. RESULTS: One hundred patients having elective CABG who were younger than 75 yr were studied. Including all complications, early extubation (n = 50) significantly reduced cardiovascular intensive care unit (CVICU) costs by 53% (P < 0.026) and the total CABG surgery cost by 25% (P < 0.019) when compared with late extubation (n = 50). Forty-one patients (82%) in each group were tracheally extubated within the defined period. In the early extubation group, the actual departmental cost savings in CVICU nursing and supplies was 23% (P < 0.005), in ward nursing and supplies was 11% (P < 0.05), and in respiratory therapy was 12% (P < 0.05). The total cost savings per patient having CABG was 9% (P < 0.001). Further cost savings using discharge criteria were 51% for CVICU nursing and supplies (P < 0.001), 9% for ward nursing and supplies (P < 0.05), and 29% for respiratory therapy (P < 0.001), for a total cost savings per patient of 13% (P < 0.001). Early extubation also reduced elective case cancellations (P < 0.002) without any increase in the number of postoperative complications and readmissions. CONCLUSIONS: Early tracheal extubation anesthetic management reduces total costs per CABG surgery by 25%, predominantly in nursing and in CVICU costs. Early extubation reduces CVICU and hospital length of stay but does not increase the rate or costs of complications when compared with patients in the late extubation group. It shifts the high CVICU costs to the lower ward costs. Early extubation also improves resource use after cardiac surgery when compared with late extubation.

Morbidity outcome in early versus conventional tracheal extubation after coronary artery bypass grafting: a prospective randomized controlled trial.

INTRODUCTION: We undertook a prospective, randomized, controlled clinical trial to evaluate morbidity outcomes and safety of a modified anesthetic technique to provide shorter sedation and early extubation (1 to 6 hours) than those of the conventional anesthetic protocol used for prolonged sedation and extubation (12 to 22 hours) in patients after coronary artery bypass grafting. METHODS: One hundred twenty patients undergoing elective coronary artery bypass grafting were prospectively assigned randomly to either an early extubation group (n = 60; 15 micrograms.kg-1 fentanyl and 2 to 6 mg.kg-1.hour-1 propofol and isoflurane) or to a conventional extubation group (n = 60; 50 micrograms.kg-1 fentanyl and 0.1 mg.kg-1 midazolam and isoflurane). Cardiac morbidity (postoperative myocardial ischemia, postoperative myocardial infarction, and perioperative sympathoadrenal stress response), respiratory morbidity (postextubation apnea, alveolar-arterial oxygen gradient, pulmonary shunting, oxygen consumption, atelectasis, and reintubation), hemodynamic values and vasoactive medication requirements, intraoperative awareness, postoperative cognitive function, 30 day mortality, and intensive care unit and hospital lengths of stay were compared between the two groups. RESULTS: Fifty-one of the 60 patients in each group (85%) were extubated within the defined time period. Postoperative extubation time and intensive care unit and hospital lengths of stay were significantly shorter in the early group. At 48 hours after operation, there were no significant differences between the two groups in myocardial ischemia incidences, ischemia burdens, or creatine kinase isoenzyme MB levels. Four patients in the conventional group, but not in the early group, had postoperative myocardial infaction. The extubation anesthetics used were effective in suppressing the perioperative plasma catecholamine stress response in both groups. Postextubation apnea characteristics were similar between the groups. Intrapulmonary shunt fraction improved significantly in the early group at 4 hours after extubation. The incidences and degree of atelectasis did not differ significantly between the two groups. The incidences of treated postoperative complications were comparable between the two groups, but three patients in the conventional group died as a result of stroke or postoperative myocardial infarction. CONCLUSION: Early extubation after coronary artery bypass grafting is safe and does not increase perioperative morbidity. There is an improvement in postextubation intrapulmonary shunt fraction and a reduction in intensive care unit and hospital lengths of stay.

Comparison of nifedipine and metoprolol on collateral coronary blood flow in a swine model of chronic coronary obstruction and acute ischaemia during isoflurane anaesthesia.

PURPOSE: This study compared the effects of nifedipine and metoprolol on collateral-dependent myocardial blood flow in a swine model of chronic coronary obstruction and acute ischaemia during isoflurane anaesthesia. METHODS: Collateral coronary circulation was induced in 15 three-week-old piglets by banding of the proximal left anterior descending coronary artery (LAD). After 8-10 wk, the distal LAD was ligated and the open-chest pigs were randomized to receive infusions of either saline, nifedipine (5 micrograms.kg-1.min-1) or metoprolol (10 micrograms.kg-1.min-1) for 30 min during isoflurane anaesthesia (2%). Transient ischaemia was induced by 30 sec occlusion of the left circumflex artery. Arterial blood pressures, heart rate and regional myocardial blood flow (radiolabelled microspheres technique) were measured at the end of drug infusion (baseline) and one minute after transient ischaemia. RESULTS: No differences in the blood flow to the collateral-dependent (CD) myocardium or haemodynamic variables were observed at baseline among the three groups. Following transient ischaemia, in the nifedipine but not in the metoprolol group, blood flow to the CD myocardium was reduced by 28 +/- 24% in the epicardium (P < 0.05) and 56 +/- 20% in the endocardium (P < 0.01), resulting from intercoronary and transmural steal. This was associated with a moderate increase (10%, P < 0.05) in the heart rate in the nifedipine group. CONCLUSIONS: In a swine model of chronic coronary obstruction and acute ischaemia during isoflurane anaesthesia, the collateral coronary blood flow was maintained in the presence of metoprolol, but reduced in the presence of nifedipine following transient ischaemia due to intercoronary and transmural steal.

Coagulopathies in patients after transurethral resection of the prostate: spinal versus general anesthesia.

This prospective, randomized study evaluated the effects of spinal versus general anesthetic technique on perioperative blood loss and the development of postoperative coagulopathies in 50 patients undergoing transurethral resection of the prostate (TURP). Preoperative hematologic measurements included hemoglobin, platelet count, electrolytes, prothrombin time, partial thromboplastin time, fibrinogen, factor V, plasminogen, antithrombin III, and fibrinogen degradation product (FDP) levels. All hematologic blood samples wre repeated postoperatively at 1, 6, and 24 h. Intraoperative blood loss was not significantly different between the spinal and general anesthesia groups. The total blood loss after TURP was significantly correlated (r = 0.76; P < 0.0001) with the prostatic tissue weight. When the tissue weight resected exceeded 35 g, blood loss was in excess of the linear correlation shown with the weight of resected prostatic tissue. Platelet count decreased and prothrombin time increased in the spinal group at all postoperative time intervals compared to preoperative value (P < 0.05). There was no significant difference in measured coagulation variables (fibrinogen, factor V, plasminogen, antithrombin III, and FDP) between the spinal and general anesthesia groups, but there were significant decreases in postoperative fibrinogen and Factor V levels compared to preoperative values in both spinal and general anesthesia groups. Three patients (6%) had increased FDP levels 1 h postoperatively. The prostatic tissue weight and the surgical duration was significantly higher in these patients. We conclude that perioperative blood loss in TURP patients is not affected by the anesthetic technique. However, 6% of TURP patients developed subclinical intravascular coagulopathies which correlated with mass of resected prostate tissue.

A prospective randomized double-blinded study of the effect of intravenous fluid therapy on adverse outcomes on outpatient surgery.

This study investigated the impact of perioperative fluid status on adverse clinical outcomes in ambulatory surgery. Two hundred ASA grade I-III ambulatory surgical patients were prospectively randomized into two groups to receive high (20 mL/kg) or low (2 mL/kg) infusions of isotonic electrolyte solution over 30 min preoperatively. A standardized balanced anesthetic was used. A minimal amount of fluid was given during the intraoperative and postoperative periods. Adverse outcomes were assessed by an investigator blinded to the fluid treatment group at 30 and 60 min after surgery, at discharge, and the first postoperative day. The incidence of thirst, drowsiness, and dizziness was significantly lower in the high-infusion group at all intervals. We recommend perioperative hydration of 20 mL/kg for patients undergoing general anesthesia for short ambulatory surgery.

Amrinone therapy for severe pulmonary hypertension and biventricular failure after complicated valvular heart surgery.

We report two cases in which amrinone was used effectively, in addition to the conventional sympathomimetic drug, for the emergence from cardiopulmonary bypass following complicated valvular heart surgery in patients who had severe pulmonary hypertension and biventricular failure. Amrinone was used in combination with isoproterenol in one and dopamine in the other case. The clinical changes were brought about by a 21.5 percent and 53.5 percent decrease in pulmonary blood pressure and pulmonary vascular resistance, respectively. Concomitantly, the mean systemic blood pressure was increased by 50 percent, whereas heart rate decreased by 17.5 percent. This report demonstrates that amrinone can be life-saving in patients with biventricular failure and severe pulmonary hypertension not responding to conventional beta-adrenergic and vasodilator drug therapy.