Davy C. H. Cheng

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 (Pt < 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

INTRODUCTIONnWe 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.nnnMETHODSnOne 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.nnnRESULTSnFifty-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.nnnCONCLUSIONnEarly 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.

Pro: Early extubation after cardiac surgery decreases intensive care unit stay and cost

The recurrent or new trends of early extubation after cardiac surgery are here to stay in the 1990s. The preoperative status does not necessarily predict the postoperative course and prolonged mechanical ventilation following cardiac surgery should not be uncritically considered as routine. All patients should be assessed for tracheal extubation at the earliest opportunity when the criteria are met in the ICU. Early extubation post-cardiac surgery does reduce ICU and hospital length of stay and costs. It also allows early ICU discharge and reduces case cancellations without any increase in postoperative complications and readmission. These studies have emphasized that the change in the process of care to early extubation can affect patient outcome as well as costs in cardiac patient care. The substantial difference in cost savings per cardiac case between criteria discharge and actual discharge points out the importance of the organization of the process of care being delivered. To achieve maximum cost benefit from early extubation in cardiac patients, the organization of the perioperative management of these patients must be optimized. This process of care includes intraoperative anesthetic modification; organization of ICU and staff expertise; postoperative early extubation and management; acute pain service; ICU discharge policy; utilization of step-down unit and surgical ward; and communication among cardiac patient management teams (cardiovascular surgeon, cardiac anesthesiologist, ICU staff, nurses, respiratory therapists, physiotherapists, and social workers), which are all vital to the success of such a program.

A randomized double-blinded multicenter comparison of remifentanil versus fentanyl when combined with isoflurane/propofol for early extubation in coronary artery bypass graft surgery

We compared a fentanyl/isoflurane/propofol regimen with a remifentanil/isoflurane/propofol regimen for fast-track cardiac anesthesia in a prospective, randomized, double-blinded study on patients undergoing elective coronary artery bypass graft surgery. Anesthesia was induced with a 1-min infusion of 0.5 mg/kg propofol followed by 10-mg boluses of propofol every 30 s until loss of consciousness. After 0.2 mg/kg cisatracurium, a blinded continuous infusion of remifentanil at 1 &mgr;g · kg−1 · min−1 or the equivalent volume rate of normal saline was then started. In addition, a blinded bolus syringe of 1 &mgr;g/kg remifentanil or 10 &mgr;g/kg fentanyl, respectively, was given over 3 min. Blinded remifentanil, 1 &mgr;g · kg−1 · min−1 (or the equivalent volume rate of normal saline), together with 0.5% isoflurane, were used to maintain anesthesia. Significantly more patients (P < 0.01) in the fentanyl regimen experienced hypertension during skin incision and maximum sternal spread compared with patients in the remifentanil regimen. There were no differences between the groups in time until extubation, discharge from the surgical intensive care unit, ST segment and other electrocardiogram changes, catecholamine levels, or cardiac enzymes. The remifentanil-based anesthetic (consisting of a bolus followed by a continuous infusion) resulted in significantly less response to surgical stimulation and less need for anesthetic interventions compared with the fentanyl regimen (consisting of an initial bolus, and followed by subsequent boluses only to treat hemodynamic responses) with both drug regimens allowing early extubation.

The efficacy and resource utilization of remifentanil and fentanyl in fast-track coronary artery bypass graft surgery : A prospective randomized, double-blinded controlled, multi-center trial

We compared (a) the perioperative complications; (b) times to eligibility for, and actual time of the following: extubation, less intense monitoring, intensive care unit (ICU), and hospital discharge; and (c) resource utilization of nursing ratio for patients receiving either a typical fentanyl/isoflurane/propofol regimen or a remifentanil/isoflurane/propofol regimen for fast-track cardiac anesthesia in 304 adults by using a prospective randomized, double-blinded, double-dummy trial. There were no differences in demographic data, or perioperative mortality and morbidity between the two study groups. The mini-mental status examination at postoperative Days 1 to 3 were similar between the two groups. The eligible and actual times for extubation, less intense monitoring, ICU discharge, and hospital discharge were not significantly different. Further analyses revealed no differences in times for extubation and resource utilization after stratification by preoperative risk scores, age, and country. The nurse/patient ratio was similar between the remifentanil/isoflurane/propofol and fentanyl/isoflu-rane/propofol groups during the initial ICU phase and less intense monitoring phase. Increasing preoperative risk scores and older age (>70 yr) were associated with longer times until extubation (eligible), ICU discharge (eligible and actual), and hospital discharge (eligible and actual). Times until extubation (eligible and actual) and less intense monitoring (eligible) were significantly shorter in Canadian patients than United States’ patients. However, there was no difference in hospital length of stay in Canadian and United States’ patients. We conclude that both anesthesia techniques permit early and similar times until tracheal extubation, less intense monitoring, ICU and hospital discharge, and reduced resource utilization after coronary artery bypass graft surgery.

The Effect of Three Different Doses of Tranexamic Acid on Blood Loss After Cardiac Surgery With Mild Systemic Hypothermia (32°C)

Abstract Objective: Prophylactic administration of tranexamic acid (TA), an antifibrinolytic agent, decreases bleeding after cardiac surgery with systemic hypothermia (25°C to 29°C). Warmer systemic temperatures during cardiopulmonary bypass (CPB) may reduce bleeding and thus alter the requirement for TA. The effect of three different doses of TA on bleeding after cardiac surgery with mild systemic hypothermia (32°C) is evaluated. Design: Double-blind, prospective, randomized study. Setting: University hospital. Participants: One hundred fifty adult patients undergoing aortocoronary bypass or valvular cardiac surgery. Interventions: Patients received TA, 50 (n = 50), 100 (n = 50), or 150 (n = 50) mg/kg intravenously before CPB with mild systemic hypothermia. Measurements and Main Results: Blood loss through chest drains over 6, 12, and 24 hours after surgery and total hemoglobin loss were measured. Autotransfused blood, transfused banked blood and blood products, and coagulation profiles were measured. Analysis of variance on log-transformed data for blood loss and confidence intervals (Cis) of 0.95 were calculated and transformed to milliliters of blood. No patient was re-explored for bleeding. Blood loss at 6 hours was statistically greater in the 50-mg/kg group compared with the other two groups (p = 0.03; p = 0.02). Total hemoglobin loss was statistically greater in the 50-mg/kg group compared with the 150-mg/kg group (p = 0.04). There was no statistical difference in blood transfusion rate or coagulation profiles among the three groups. However, preoperative hemoglobin level was statistically lower in the 150-mg/kg group compared with the other two groups (p = 0.01). Conclusion: Of the three doses of TA studied, the most efficacious and cost-effective dose to reduce bleeding after cardiac surgery with mild hypothermic systemic perfusion is 100 mg/kg.

Anaesthesia for non-cardiac surgery in heart-transplanted patients

This review documents the anaesthetic management, haemodynamic function and outcome in 18 of 86 heart-transplanted recipients, who returned for 32 non-cardiac surgical procedures at the Toronto Hospital from 1985 to 1990. General anaesthesia was administered in eight of the 27 elective operations and four of the five emergency operations. Induction medications included thiopentone (2–4 mg· kg−1), fentanyl (1–7 μg· kg−1) and succinylcholine (1–1.5 mg· kg−1). Anaesthesia was maintained with a combination of oxygen /nitrous oxide and isoflurane or enflurane. Muscle relaxation was maintained with vecuronium or pancuronium. No delayed awakening or unplanned postoperative ventilation was observed. Neuroleptanaesthesia was administered to 63.0% and 20.0% of the elective and emergency operations, respectively. The anaesthetics included fentanyl (25–100 ng) and midazolam (0.5–1.5 mg) or diazemuls (2.5–5.0 mg). Spinal anaesthesia (75 mg lidocaine) was administered to only two of the 27 elective operations. No important haemodynamic changes were observed in any anaesthetic group, but lower systolic BP was found after induction and during maintenance periods in the patients who received general anaesthesia than in those who received neurolept-anaesthesia. However, no anaesthesia-related morbidity or mortality was noted. This suggests that general, neurolept- and spinal anaesthesia do not affect haemodynamic function or postoperative outcome in heart-transplanted recipients undergoing subsequent non-cardiac surgery.RésuméCet article documente la conduite anesthésique, la fonction hémodynamique et l’évolution de 18 des 86 transplantés cardiaques qui sont revenus pour 32 interventions chirurgicales non cardiaques à l’Hôpital de Toronto de 1985 à 1990. Une anesthésie générale a été administrée pour huit des 27 interventions programmées et pour quatre des cinq interventions d’urgence. Les agents d’induction comprenaient du thiopental (2.0–4.0 mg · kg−1), du fentanyl (1,0-7.0 μg · kg−1) et de la succinylcholine (1,0-1,5 mg· kg−1). L’anesthésie a été entretenue avec une combinaison d’oxygène/protoxyde d’azote et isoflurane ou enflurane. La relaxation musculaire a été maintenue avec du vécuronium ou du pancuronium. On n’a pas observé de réveil retardé ni de ventilation post-opératoire imprévue. Une neuroleptanesthésie a été administrée à 63,0% des interventions programmées et à 20% des interventions urgentes. Les agents étaient du fentanyl (25–100 μg) et du midazolam (0,5–1,5 mg) ou du diazemul (2,5–5 mg). L’anesthésie rachidienne (75 mg de lidocaïne) n’a été administrée qu’à seulement deux des 27 opérations programmées. Dans aucun groupe, on n’a observé de variations hémodynamiques importantes, mais une pression artérielle systolique plus basse a été notée après l’induction et pendant les périodes d’entretien chez les patients qui ont reçu une anesthésie générale par rapport à ceux qui ont reçu une neuroleptanesthésie. On n’a cependant pas enregistré de morbidité ni de mortalité en rapport avec l’anesthésie. Ceci suggère que l’anesthésie générale, la neuroleptanesthésie, ou l’anesthésie rachidienne n’affecte pas la fonction hémodynamique ou l’évolution post-opératoire chez les patients transplantés qui ultérieurement subissent une chirurgie non cardiaque.

Analgesic and pulmonary effects of continuous intercostal nerve block following thoracotomy

This study examined the beneficial effects and potential systemic toxicity from continuous intercostal nerve block by repeated bolus injections of bupivacaine. In this double-blind, randomized study, 20 post-thoracotomy patients were assigned to receive four doses of either: 20 ml 0.5% bupivacaine with epinephrine 5 μg · ml−1 (bupivacaine group, n = 10), or 20 ml preservative-free saline (placebo group, n = 10) through two indwelling intercostal catheters every six hours. Patients receiving intercostal bupivacaine injections had greater decreases in visual analogue pain scores (VAS) (P < 0.05) and lower 24 hr morphine requirements, 16.6 ±4.6 mg vs 35.8 ±7.2 mg, than patients in the placebo group (P < 0.05). Higher post-injection values of forced expiratory volume in one second, forced vital capacity and peaked expiratory flow rate were also observed in the bupivacaine group (P < 0.01). Repeated intercostal bupivacaine administration did lead to systemic accumulation, but the peak bupivacaine level after 400 mg was low at 1.2 ±0.2 μg · ml−1. Thus, the technique of continuous intercostal nerve block described in this study is an effective treatment for the control of post-thoracotomy pain.RésuméCette étude examine les effets bénéfiques et la toxicité systémique potentielle d’un bloc nerveux intercostal continu par des injections répétées de bupivacaïne. Dans cette étude randomisée chaque six heures à double insu, 20 patients posl-thoracotomie ont été divisés afin de recevoir quatre doses de soit: 20 ml 0,5% de bupivacaïne avec épinéphrine 5 μg · ml−1 (groupe bupivacaïne, n = 10), ou 20 ml de soluté physiologique sans préservatif (groupe placébo, n = 10) via un cathéter intercostal chaque six heures. Les patients recevant des injections de bupivacaïne intercostal ont démontré une plus grande diminution dans le test du «Visual analogue pain scores (VAS) (P < 0.05)» et ont requis en 24 heures moins de morphine, 16,6 ±4,6 mg vs 35,8 ±7,2 mg que les patients du groupe placebo (P < 0.05). Les valeurs post-injection plus élevées étaient notées dans le FEV1, la capacité vitale forcée et le flot expiratoire maximal pour le groupe bupivacaïne (P < 0.01). L’administration répétée de bupivacaïne intercostale a amené une accumulation systémique mais le niveau maximal de bupivacaïne après 400 mg était bas à 1,2 ±0,2 μg · ml−1. Ainsi, la technique du bloc nerveux intercostal continu décrite dans cette étude fut un moyen thérapeutique efficace pour le contrôle de la douleur post-thoracotomie.

Cocaine toxicity and isoflurane anesthesia: Hemodynamic, myocardial metabolic, and regional blood flow effects in swine

OBJECTIVESnIncreasing numbers of people use cocaine recreationally and may require anesthesia care, having recently abused the drug. However, no data currently exist concerning potential interactions between toxic levels of cocaine and volatile anesthetic agents. This study investigated the effects of cocaine infusion on systemic hemodynamics, myocardial metabolism, and regional organ blood flow in relation to depth of isoflurane anesthesia.nnnDESIGNnProspective, randomized, controlled trial.nnnSETTINGnA laboratory at a university medical center.nnnPARTICIPANTSnTwelve miniature pigs.nnnINTERVENTIONSnAn open-chest swine model was used. Isoflurane (ISO) was the sole anesthetic, administered at 0.75 and 1.5 minimum alveolar concentration (MAC), and cocaine was infused (n = 6) at a rate of 0.5 mg/kg/min. Control animals (n = 6) received an equivalent amount of normal saline.nnnMEASUREMENTS AND MAIN RESULTSnSystemic and pulmonary arterial pressures and thermodilution cardiac output data were collected at 0.75 MAC and 1.5 MAC ISC. Regional myocardial and blood flows to other organs were measured using radiolabeled microspheres. Arrhythmias and altered ventricular conduction were noted only in the cocaine group, along with significant elevations in diastolic arterial pressure, coronary perfusion pressure, and systemic vascular resistance. Increased subendocardial blood flow occurred during cocaine infusion (p = 0.03); subepicardial perfusion was unchanged. Cerebral (p < 0.01) and spinal cord (p < 0.05) blood flows were reduced in animals receiving cocaine. Other organ blood flows were unchanged with depth of anesthesia or cocaine administration, with the exception of splenic blood flow (p < 0.04).nnnCONCLUSIONSnModerately toxic cocaine levels occurring during isoflurane at 0.75 MAC and 1.5 MAC are associated with hemodynamic abnormalities, a marked increase in systemic vascular resistance, and a tendency to produce cardiac arrhythmias. A reversal of endo/epicardial myocardial perfusion ratio occurs associated with cocaine infusion during ISO anesthesia. This is probably not related to a primary redistribution of subendocardial blood flow and may be related to a combination of increased myocardial oxygen demand and epicardial coronary vasoconstriction. The reductions in cerebral and spinal cord perfusion observed may explain, in part, the neurologic sequelae of cocaine toxicity.

Duration of preoperative amiodarone treatment may be associated with postoperative hospital mortality in patients undergoing heart transplantation

OBJECTIVEnTo assess the effect of preoperative amiodarone treatment on patient mortality after heart transplantation.nnnDESIGNnRetrospective study.nnnSETTINGnSingle-institution university hospital.nnnPARTICIPANTSnOne hundred six consecutive patients with heart transplants.nnnINTERVENTIONSnNone.nnnMEASUREMENTS AND MAIN RESULTSnPatients were grouped according to duration of preoperative amiodarone treatment, and posttransplant mortality before hospital discharge was compared with patients not treated with amiodarone. The authors collected cardiovascular data in the preoperative and postoperative periods. There was a significant increase in posttransplant mortality before hospital discharge in patients treated with amiodarone for more than 4 weeks in the preoperative period (p < 0.05). Patients treated with amiodarone had significantly lower (p < 0.05) heart rates (mean heart rate, 103+/-19 beats/min) in the early postoperative period than patients not treated with amiodarone (mean heart rate, 111+/-15 beats/min), but there was no relationship with mortality (p = not significant). Patients who died had a significantly lower (p < 0.05) postoperative cardiac index (2.2+/-0.7 to 2.5+/-0.7) in the first 24 hours after cardiopulmonary bypass compared with patients who survived to hospital discharge (3.0+/-0.7 to 3.1+/-0.9), but there was no relationship to amiodarone treatment (p = not significant).nnnCONCLUSIONnPreoperative amiodarone treatment for more than 4 weeks may be associated with a significant increase in postoperative mortality in patients undergoing heart transplantation. Therefore, the indications for amiodarone must be carefully considered and, if needed, the maintenance dose should be kept to a minimum.