Efficacy of preoperative autologous blood donation: analysis of blood loss and transfusion practice in total hip replacement.

STUDY OBJECTIVE: To determine the frequency of allogeneic transfusion for total hip replacement (THR) surgery and to examine the efficacy of preoperative autologous blood donation (PABD) under specified, standardized blood transfusion guidelines. DESIGN: Prospective, nonrandomized study. SETTING: University medical center. PATIENTS: All ASA physical status I, II, III, and IV patients undergoing single, primary, THR surgery from April 1998 to March 1999. INTERVENTIONS: All patients received standardized transfusion and anticoagulation therapy. Demographic, blood loss, and transfusion data were collected and compared between all patients participating in PABD (donors) and patients not participating in PABD (nondonors). Overall allogeneic blood exposure was established. Since most anemic patients could not participate in PABD, allogeneic transfusion frequency was also examined in a subset of nonanemic patients (hemoglobin > or =12 g/dL) who were potentially able to participate in PABD. MEASUREMENTS AND MAIN RESULTS: n = 231 patients, 142 donors and 89 nondonors. Mean estimated blood volume (EBV) of donors was 4991 +/- 1042 mL versus nondonors 4631 +/- 1108 mL (p < 0. 01). ASA physical status I-II/III-IV among donors was 118/24 versus nondonors 61/28 (p < 0.01). Overall allogeneic blood exposure was 22% (51/231). Allogeneic transfusion frequency for all donors was 15% (22/142) versus nondonors 33% (29/89) (p < 0.05). Among nonanemic patients, donor versus nondonor EBV and ASA physical status I-II/III-IV were 5074 +/- 1019 mL versus 4743 +/- 1172 mL and 107/20 versus 48/15 (p = NS); allogeneic transfusion frequency reduced to 13% (16/127) versus 17% (11/63) (p = NS), respectively. CONCLUSIONS: Allogeneic blood exposure was >10% despite the use of PABD. The efficacy of PABD has been obscured by the fact that donors of autologous blood tend to be larger and healthier than nondonors. After exclusion of anemic patients, autologous donors and nondonors were clinically comparable and the difference in allogeneic blood exposure was not statistically significant. PABD offers only a modest, if any, benefit for THR surgery.

Atrial natriuretic peptide responses during anaesthesia in patients with refractory cardiomyopathies.

In patients with congestive heart failure, the release of atrial natriuretic peptide (ANP) is decreased. This study sought to determine the extent of ANP, sympathetic and haemodynamic responses to acutely increased atrial pressure in patients with cardiomyopathies undergoing orthotopic cardiac transplantation. Haemodynamic variables, plasma ANP, norepinephrine, and epinephrine concentrations were measured in 17 patients at five times before and after induction of anaesthesia using either ketamine 1.5 micrograms.kg-1 or sufentanil 3.6 +/- 0.3 micrograms.kg-1. Preinduction values in the ketamine and sufentanil groups were not significantly different. Compared with preinduction values, increases in mean arterial pressure (26%), pulmonary capillary wedge pressure (90%), right atrial pressure (107%), and heart rate (24%) occurred in the ketamine group while cardiac index decreased by 19% (P less than 0.05). Haemodynamic variables in the sufentanil group did not change at any of the times studied. Plasma concentrations of atrial natriuretic peptide were not different within or between treatment groups. Following tracheal intubation plasma norepinephrine levels increased by 116% in the ketamine group (P less than 0.05), but did not change in the sufentanil group. Plasma norepinephrine concentrations differed significantly between the ketamine and sufentanil groups. There were no differences in epinephrine concentrations in either group. Despite the anticipated haemodynamic and catecholamine differences found between the ketamine and sufentanil groups, the levels of plasma ANP were similar. Based upon these results, it is concluded that ANP exerts little influence in the control of fluid volume or blood pressure in patients with refractory cardiomyopathy.

Cardiac transplantation: a prospective comparison of ketamine and sufentanil for anesthetic induction.

The hemodynamic effects of ketamine, 1.5 mg/kg, or sufentanil, 3.4 +/- 0.3 micrograms/kg, were studied prospectively for the anesthetic induction of 20 patients with cardiomyopathies undergoing cardiac transplantation. Plasma epinephrine (EPI), norepinephrine (NE), and sufentanil levels were also obtained. Measurements were taken at various times before induction and following intubation. Following ketamine, progressive increases (P less than 0.05) in mean arterial pressure (28%, MAP), mean pulmonary artery pressure (56%, PAP), central venous pressure (109%, CVP), and pulmonary capillary wedge pressure (84%, PCWP) occurred over time, whereas the cardiac index (CI), stroke volume index (SVI), and stroke work index (SWI) remained unchanged or decreased. The use of sufentanil was associated with no significant changes in MAP, PAP, CVP, PCWP, CI, SVI, or SWI. The heart rate (HR) did not significantly change in either group. Plasma NE significantly increased (31%) in the ketamine group, peaking at 10 minutes; whereas EPI levels did not significantly change in either group. Plasma sufentanil did not reflect the microgram/kg or microgram/BSA administered dose, suggesting individualized distribution kinetics. Since perioperative morbidity and mortality did not differ between groups, both ketamine and sufentanil are acceptable drugs for the anesthetic induction for cardiac transplantation. However, the dissimilar hemodynamic effects caused by ketamine and sufentanil suggest that this conclusion may not be applicable to the patient with a cardiomyopathy undergoing noncardiac surgery.

Plasma catecholamine changes during excision of pheochromocytoma.

Sequential changes in plasma norepinephrine (NE) and epinephrine (EPI) concentration were correlated with changes in blood pressure and cardiac rate in 14 patients undergoing surgery because of pheochromocytoma. All patients had elevated preoperative plasma catecholamine levels that increased during induction of anesthesia, intubation, and skin incision, but mean values did not become significantly higher than preoperative values until tumor manipulation. Episodes of hypertension were associated with increased plasma catecholamine levels, and plasma catecholamine levels and blood pressure decreased dramatically after tumor resection. NE and EPI were usually secreted simultaneously, but release of either NE or EPI alone occurred on some occasions. There were marked variations in the concentration ratio of NE to EPI in plasma at different periods of observation, which suggests that pheochromocytomas release varying amounts of catecholamines in a random fashion. Studies of the effect of the duration of preoperative preparation on intraoperative blood pressure, pulse rate, and cardiac arrhythmias failed to demonstrate that treatment for 14 days or longer was more effective than treatment for 4 to 7 days. Neither the brief nor the prolonged period of therapy prevented development of severe hypertension during tumor manipulation.

Investigation of midazolam's influence on physiological and hormonal responses to hypotension.

Midazolam differs from diazepam in that midazolam is water-soluble, more potent and has a shorter elimination half-life (t1/2). To date, it has been used primarily for induction of anesthesia and as an anesthetic supplement. Diazepam has been shown to decrease the catecholamine response to perioperative stress. This study determined the extent to which midazolam influences the physiological and hormonal responses that are evoked by a nitroprusside-induced hypotensive challenge. Plasma levels of epinephrine, norepinephrine (NE), cortisol, and renin activity, as well as hemodynamic performance were measured in dogs anesthetized with enflurane-nitrous oxide-oxygen. Midazolam 0.2 mg/kg i.v. administered prior to a 30% decrease in mean blood pressure statistically attentuates the increase in plasma catecholamines. The cortisol and renin increases that occurred in response to the hypotension were not affected appreciably by midazolam. Hemodynamic changes due to midazolam were minimal, with only a transient 8-10% decrease in mean blood pressure observed. The findings of this study demonstrate that midazolam, like diazepam and fentanyl, can reduce the physiological and hormonal response to hypotensive episodes that occurred during the course of anesthesia and surgery.

Qualitative evaluation of coronary flow during anesthetic induction using thallium-201 perfusion scans.

Qualitative distribution of coronary flow using thallium-201 perfusion scans immediately postintubation was studied in 22 patients scheduled for elective coronary artery bypass surgery. Ten patients received a thiopental (4 mg/kg) and halothane induction. Twelve patients received a fentanyl (100 micrograms/kg) induction. Baseline thallium-201 perfusion scans were performed 24 h prior to surgery. These scans were compared with the scans performed postintubation. A thallium-positive scan was accepted as evidence of relative hypoperfusion. Baseline hemodynamic and ECG data were obtained prior to induction of anesthesia. These data were compared with the data obtained postintubation. Ten patients developed postintubation thallium-perfusion scan defects (thallium-positive scan), even though there was no statistical difference between their baseline hemodynamics and hemodynamics at the time of intubation. There was no difference in the incidence of thallium-positive scans between those patients anesthetized by fentanyl and those patients anesthetized with thiopental-halothane. The authors conclude that relative hypoperfusion, and possibly ischemia, occurred in 45% of patients studied, despite stable hemodynamics, and that the incidence of these events was the same with two different anesthetic techniques.

Haemodynamic and catecholamine response to isoflurane anaesthesia in patients undergoing coronary artery surgery.

Haemodynamic and plasma catecholamine responses were evaluated during isoflurane anaesthesia in ten patients undergoing coronary artery bypass surgery. Following thiopentone induction the patients were anaesthetized with isoflurane 1.5-2.0 per cent in oxygen. The results show that after 10 minutes of isoflurane anaesthesia there was a significant increase from baseline in heart rate, 68 to 80; cardiac output, 3.75 to 4.61; and plasma epinephrine, 0.80 to 1.33 microgram/l. Conversely, there was a significant reduction in systemic vascular resistance index, 3388 to 2260, and plasma norepinephrine, 1.10 to 0.88 microgram/l. Twenty-five minutes later, after sternotomy, heart rate, cardiac output and the level of plasma epinephrine were still elevated, and systemic vascular resistance index and plasma norepinephrine remained lowered (p less than 0.05). This study demonstrates significant catecholamine responses during isoflurane anaesthesia. The increase in plasma epinephrine parallelled the increase in heart rate and cardiac output, and the decrease in plasma norepinephrine paralleled the decrease in systemic vascular resistance. Based upon these findings we conclude that catecholamine responses contribute to the cardiac and peripheral cardiovascular changes observed with isoflurane anesthesia.

Epidural triamcinolone and adrenal response to hypoglycemic stress in dogs.

The effect of an epidural steroid injection (triamcinolone) on plasma cortisol levels was studied in twelve beagle dogs following an insulin-induced hypoglycemic stress. The control group (n = 6) received epidural bupivacaine only. This group consistently increases their plasma cortisol values in response to the hypoglycemic stress induced by 0.6 units of insulin/kg administered intravenously. Dogs in the study group (n = 6) received epidural bupivacaine plus 2 mg/kg of triamcinolone. This group was unable to increase their plasma cortisol values in response to similar insulin-induced hypoglycemic stress for four weeks. Return to normal function occurred five weeks following epidural triamcinolone. The authors hypothesize that the inability of the dogs to respond to hypoglycemic stress by increasing their plasma cortisol may interfere with homeostasis and decrease their tolerance to other types of stress up to 4 weeks following epidural triamcinolone administration.

Effect of priming volume on serum catecholamines during cardiopulmonary bypass.

Several theories have been proposed to explain the transient hypotension which occurs upon the initiation of cardiopulmonary bypass. The present study investigated the possibility that addition of the lactated Ringer's solution pump priming volume to the circulation causes dilution of circulating catecholamines leading to the hypotension. Circulating epinephrine and norepinephrine levels were measured during cardiopulmonary bypass in patients anaesthetized with halothane. The results demonstrate dilution of circulating catecholamines at the start of bypass in conjunction with the observed hypotension. During the bypass period, mean blood pressure graudally recovered to normotensive levels even though circulating catecholamine levels remained significantly lowered, indicating a mechanism for the recovery of blood press which is not sympathoadrenal. The results obtained from this study demonstrate a temporal relationship between catecholamine dilution by the pump priming volume and the observed hypotension. Whether catecholamine dilution is the sole factor causing the hypotension remains to be determined.

Nitroglycerin and the neuromuscular blockade produced by gallamine, succinylcholine, d-tubocurarine, and pancuronium.

The finding in cats of prolonged pancuronium neuromuscular blockade in conjunction with intravenous infusion of nitroglycerin was previously reported by this laboratory. To expand on this finding the present study compared the effects of nitroglycerin on neuromuscular blockade produced by gallamine, d-tubocurarine, succinylcholine, and pancuronium, and further characterized the nitroglycerin-pancuronium interaction. The results indicate that of the relaxants studied only pancuronium neuromuscular blockade is prolonged, and that the prolongation is not due to altered plasma elimination of pancuronium. In vitro pancuronium blockade was not affected by nitroglycerin, suggesting the involvement of a metabolite in the block prolongation response. Reversibility of the prolonged pancuronium block by neostigmine is not influenced by nitroglycerin.

Prolongation of pancuronium-induced neuromuscular blockade by intravenous infusion of nitroglycerin.

Based upon clinical observation of undue prolongation of pancuronium-induced blockade in the presence of intravenous infusion of nitroglycerin, neuromuscular blockades produced by pancuronium, succinylcholine and d-tubocurarine were studied in 51 cats using the sciatic-gastrocnemius nerve-muscle preparation. Pancuronium-induced blockade was found to be significantly prolonged (P less than 0.1) in the presence of a nitroglycerin infusion of 1 microgram/kg/min (65 vs. 127 min). Less, but still significant, prolongation occurred when nitroglycerin, 0.5 microgram/kg/min, was infused. The intravenous infusion of nitroglycerin must be started prior to the pancuronium injection for the block to be prolonged. Neuromuscular blocks produced by succinylcholine and d-tubocurarine were not altered by nitroglycerin. In experiments using the isolated rat diaphragm preparation, the depth of pancuronium-induced block was found not to be changed by nitroglycerin, suggesting an effect of nitroglycerin on the process of recovery from blockade. These findings indicate a selective pancuronium-nitroglycerin interaction.

Serum epinephrine and norepinephrine during valve replacement and aorta-coronary bypass.

A comparison of the levels of serum epinephrine, norepinephrine and blood pressure was made in 25 patients undergoing aorta-coronary bypass or valve replacement who were anaesthetized with a nitrous oxide-narcotic technique. Serum epinephrine and norepinephrine were measured in arterial samples drawn pre-induction, post-induction, before cardiopulmonary bypass, two and eight minutes after initiation of cardiopulmonary bypass, 20 minutes before termination and after termination of cardiopulmonary bypass. In both patient groups significant increases in epinephrine and norepinephrine occurred befored cardiopulmonary bypass, with accompanying increase of blood pressure in the valve replacement patients. During cardiopulmonary bypass an initial hypotensive response (p less than 0.001) was recorded, followed by a significant increase in blood pressure and epinephrine in both groups. After cardiopulmonary bypass, aorta-coronary bypass patients had epinephrine, norepinephrine and blood pressure equal to levels before cardiopulmonary bypass. In contrast, serum epinephrine continued to rise in the valve replacement patients, with a gradual recovery of blood pressure to pre-bypass levels. These findings demonstrate significant differences in blood pressure and catecholamine response in patients with valvular disease from patients with coronary artery disease.

Amitriptyline therapy increases electrocardiographic changes during reversal of neuromuscular blockade.

Induction of anesthesia is associated with an increased incidence of cardiac arrhythmias in patients maintained on amitriptyline medication. This study presents additional evidence showing that, in experimental animals (cats), amitriptyline treatment also produces significant ST-T wave and conduction abnormalities during neostigmine reversal of neuromuscular blockade.

Enflurane anesthesia for surgical removal of pheochromocytoma.

Four cases describing the use of enflurane as the main anesthetic during surgical removal of pheochromocytoma (PCC) are presented and the preoperative preparation and intraoperative management of the patients are discussed. Serum levels of epinephrine and norepinephrine were measured in 3 of the reported cases. Intraoperative values were extremely elevated during tumor manipulation, but there was only 1 minor episode of arrhythmias. Criteria for choosing anesthetic agents for surgical removal of PCC are outlined. The authors conclude from their experience and that of others that enflurane is as safe and effective an anesthetic as any now available for PCC excision.