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Urinary diversion by transplantation of both ureters into a reservoir constructed from 60 cm of jejunum was performed in six clinically normal dogs. The reservoir was connected to a stoma on the abdominal wall through a valve constructed from a short segment of intussuscepted bowel to provide continence. The reservoir was emptied three times daily by catheterization. One dog did not survive the surgical procedure and two dogs died within 1 week of surgical complications. The postoperative capacity of the reservoir in surviving dogs was 100 to 200 mL; it increased during the first month to 600 to 750 mL. Continence was excellent in two dogs. One dog was continent until month 2, when partial slippage of the intussusception occurred. A reversible hyponatremic, hypochloremic, hypokalemic metabolic acidosis developed. Bacteriuria was not responsive to systemic or local instillation of antibiotics. Ascending pyelonephritis, hydroureter, and hydronephrosis occurred in two dogs. Struvite urinary calculi formed in one dog. The procedure as described would be unsuitable for clinical use in dogs.

The Hopkins Competency Assessment Test (HCAT), a brief instrument for evaluating the competency of patients to give informed consent or write advance directives, consists of a short essay and a questionnaire for determining patients' understanding of the essay. In a study to validate the instrument, 41 medical and psychiatric inpatients answered the questionnaire after reading the essay while bearing it read aloud. A forensic psychiatrist who was blind to the HCAT scores later examined the patients for competency. A subject's number of correct answers to the HCAT questionnaire was an accurate indicator of clinical competency as assessed by the psychiatrist. The results suggest that the HCAT is a useful tool for rapidly screening patients for competency to make treatment decisions.

Mixed venous oxygen saturation (SvO2) monitoring has been advocated for some critically ill patients. Patients with end-stage hepatic failure have oxygen consumption rates that are lower than normal. Using the Fick equation, oxygen consumption may be calculated if mixed venous and arterial oxygen tensions (and saturations), hemoglobin, and cardiac output are determined simultaneously. This report describes a unique pattern of changes in SvO2 and oxygen consumption in 7 patients undergoing liver transplantation. A previous study correlated plasma carbohydrate (glucose) levels with early hepatic graft survival. After induction, the 7 patients reported here had low oxygen consumption and high SvO2 values. The oxygen consumption rates decreased to the lowest point during the anhepatic phase and rose above baseline by the end of the case. The SvO2 and oxygen consumption data reported here follow the presence of presumed hepatic metabolic activity (increased CO2 and ionized calcium). Further research must be completed to determine whether these measurements indicate early hepatic nonfunction.

To examine the interaction of epidural anesthesia, coagulation status, and outcome after lower extremity revascularization, 80 patients with atherosclerotic vascular disease were prospectively randomized to receive general anesthesia combined with postoperative epidural analgesia (GEN-EPI) or general anesthesia with on-demand narcotic analgesia (GEN). Demographics did not differ between groups except that the GEN-EPI group had a higher incidence of diabetes mellitus and of previous myocardial infarction. Coagulation status was monitored using thromboelastography. An additional 40 randomly selected patients without atherosclerotic vascular disease undergoing noncardiovascular procedures served as controls for coagulation status. Vascular surgical patients were hypercoagulable compared with control patients before operation and on the first postoperative day. Postoperatively, this hypercoagulability was attenuated in the GEN-EPI group and was associated with a lower incidence of thrombotic events (peripheral arterial graft coronary artery or deep vein thromboses). The rates of cardiovascular, infectious, and overall postoperative complications, as well as duration of intensive care unit stay, were significantly reduced in the GEN-EPI group. Stepwise logistic regression demonstrated that the only significant predictors of postoperative cardiovascular complications were preoperative congestive heart failure and general anesthesia without epidural analgesia. We conclude that in patients with atherosclerotic vascular disease undergoing arterial reconstructive surgery (a) thromboelastographic evidence of increased platelet-fibrinogen interaction is associated with early postoperative thrombotic events, and (b) epidural anesthesia and analgesia is associated with beneficial effects on coagulation status and postoperative outcome compared with intermittent on-demand opioid analgesia.

Although reported in the aerospace literature and anecdotally by anesthesiologists, the putative antiemetic effect of ephedrine remains unquantitated. We therefore prospectively studied ephedrine as an antiemetic agent in the perioperative setting in 97 patients undergoing general anesthesia for outpatient gynecologic laparoscopy. Patients were assigned in a double-blind randomized fashion to receive a standardized general anesthetic followed by an intramuscular dose of either ephedrine (0.5 mg/kg), droperidol (0.04 mg/kg), or saline before the conclusion of surgery. Nausea, retching, or vomiting, as well as the degree of sedation and discharge times, were assessed in the recovery room and for 24 h postoperatively. Ephedrine was found to have a significantly antiemetic effect (P less than 0.05) when compared with placebo and an antiemetic effect similar to that of droperidol. Sedation scores were also significantly less in the ephedrine group than in both placebo and droperidol groups. Finally, variations in mean arterial blood pressure among the three groups were not statistically significant. We conclude that ephedrine is an effective antiemetic agent with minimal sedative side effects in patients undergoing outpatient laparoscopy.

Supraventricular tachydysrhythmias are a commonly encountered clinical problem after cardiothoracic surgery. Current choices for acute drug therapy of these dysrhythmias include intravenous verapamil as well as esmolol, but no data yet exist comparing the relative negative dromotropic (atrioventricular [A-V] nodal blocking) and negative inotropic effects of these agents. The purpose of this study was to compare the effects of esmolol with those of verapamil on systemic hemodynamics, coronary blood flow, and cardiac contractility at doses that produce a similar ventricular response rate in an animal model of a supraventricular tachydysrhythmia. Rapid electrical stimulation (800 impulses/min) of the left atrium in 14 dogs resulted in a rapid and irregularly irregular ventricular rhythm. Esmolol or verapamil were administered by bolus and then infusion to incrementally slow the average ventricular rate. Regional myocardial contractility was measured using the end-systolic pressure-length relationship (Ees). At drug doses that produced similar decreases in ventricular rate, esmolol produced a greater decrease in contractility (Ees: 284 +/- 46 to 40 +/- 22 mmHg/mm, LV dp/dt: 2,400 +/- 450 to 1,360 +/- 450 mmHg/sec) compared with that following verapamil (Ees: 297 +/- 57 to 116 +/- 25 mmHg/mm, LV dp/dt: 2,040 +/- 580 to 1,950 +/- 520 mmHg/sec). This was accompanied by a modest decrease in cardiac output in the esmolol group (2,800 +/- 940 to 2,290 +/- 730 ml/min) compared with an unchanged cardiac output as ventricular rate slowed in verapamil-treated animals. Stroke volume increased significantly in the verapamil-treated animals (10.9 +/- 4.0 to 18.5 +/- 4.6 ml), but remained unchanged following esmolol.(ABSTRACT TRUNCATED AT 250 WORDS)

The combination of benzodiazepines and high-dose narcotics has been reported to produce hypotension in patients undergoing coronary artery surgery. This study was performed to evaluate the cardiovascular effects of lower doses of the narcotic sufentanil administered with the benzodiazepine midazolam. Thirty adult patients with good ventricular function undergoing elective coronary revascularization received sufentanil, 2.5 micrograms/kg, and midazolam, 0.1 mg/kg, followed by infusions of sufentanil, 0.7 to 1.5 micrograms/kg/h, and midazolam, 0.07 to 0.15 mg/kg/h. Overall, stable hemodynamics were achieved before and after cardiopulmonary bypass (CPB). Patients who were not receiving preoperative beta-adrenergic blockade (n = 15) had increases from baseline heart rate and rate-pressure product after sternotomy, during aortic dissection, and after CPB that were not clinically significant. Five patients developed hypertension (increases greater than 20% over the baseline value), which was controlled with additional sufentanil or a vasodilator. Hypertension requiring vasodilator therapy did not occur in patients taking beta-adrenergic blockers. Blood pressure decreases exceeding 20% of the baseline value did not occur. Two of 15 patients receiving beta-blockers, versus 3 of 15 not receiving beta-blockers, developed ischemic electrocardiographic changes before CPB (NS); one of these patients without beta-blockade had a postoperative myocardial infarction. The results of this study show that the infusion of low doses of sufentanil with midazolam provides a hemodynamically safe and stable anesthetic for coronary artery surgery and avoids the hypotension seen when a high-dose narcotic is combined with a benzodiazepine.

A prospective study of 324 adult patients undergoing operations requiring cardiopulmonary bypass for heart valve replacement was undertaken to determine the effect of anesthetic technique on outcome. Patients received one of three primary techniques: fentanyl (40-100 micrograms/kg), sufentanil (4-8 micrograms/kg), or diazepam (0.4-1 mg/kg) with ketamine (3-6 mg/kg). Supplemental inhalation anesthesia with enflurane, halothane, or isoflurane was used in 43.8% of cases. Patients in these anesthetic groupings had similar perioperative demographic and risk classifications. Although there were differences in the requirements for vasopressors postoperatively among the intravenous anesthetic agents, neither mortality rates, length of ICU stay, nor incidence of postoperative heart failure showed the advantage of any intravenous or inhalational agent. There were also no significant differences in the incidences of serious pulmonary, renal, or neurologic morbidity among primary anesthetic techniques nor among supplemental inhalation agents. Multivariate discriminant analysis of these data suggests that many factors are significantly more important than anesthetic technique as determinants of outcome after heart valve replacement.

Experiments were performed in rats to determine if the alpha 2-adrenergic agonist tizanidine has an antinociceptive effect when injected intrathecally, and whether the analgesia is accompanied by changes in blood pressure. Rats were chronically implanted with catheters in the lumbar subarachnoid space. Antinociception was evaluated in conscious rats with the tail-flick test. Increasing tizanidine doses produced increases in analgesic efficacy, with 25 micrograms producing a significant long-lasting antinociception. This tail-flick analgesia was very similar to that produced by clonidine (25 micrograms) and morphine (8 micrograms) in peak effect and duration. Doses as high as 250 micrograms produced only a transient hind limb motor dysfunction in 43% of the animals. Daily injections of 25 micrograms tizanidine over 5 days produced a decrease in antinociception, with the peak effect at day 5 at 59% of that at day 1. Blood pressure, in rats lightly anesthetized with halothane, was not affected by tizanidine injections up to 250 micrograms. Tizanidine appears to be a promising non-opiate analgesic for intrathecal usage.

The protective effects of a perfluorocarbon emulsion (FC-43) against the physiological sequelae of selective coronary air embolism (CAE) were examined in dogs. Animals were randomly assigned to two groups: group 1 received 20 mL/kg of 6% hetastarch in 0.9 normal saline solution with 280 mg/L of CaCl2; group 2 received 20 mL/kg of FC-43 (Oxypherol, Alpha Therapeutic Corp, Los Angeles). Infusion time for both groups was 30 minutes. Following a ten-minute stabilization period, a 0.02-mL/kg bolus of air was injected into the left anterior descending coronary artery distal to the first branch. Surface and epicardial ECGs, systemic BP, pulmonary artery pressure, central venous pressure, left ventricular pressure, left ventricular end-diastolic pressure (LVEDP), dP/dtmax, and Vmax were recorded continuously. Cardiac output (by thermodilution technique), myocardial creatine phosphokinase levels and the lactic acid concentration were measured. The study revealed a significantly lower systemic mean arterial pressure (MAP), LVEDP, left ventricular stroke work index (LVSWI), and right ventricular stroke work index (RVSWI) in the group receiving the FC-43 prior to receiving CAE. Possible causes of the differences are a species-specific direct vasodilating effect of FC-43 or histamine release. Following CAE, myocardial function as measured by dP/dtmax, Vmax, and MAP was lower in group 1 during the first five minutes following CAE. ECG tracings showed all of the ten group 1 dogs had ST-T changes (greater than 2 mm), and six of the ten had ventricular dysrhythmias or conduction defects. Only one of the group 2 dogs showed ST-T wave changes (P = .0006, Fisher's exact test), and none had dysrhythmias (P = .005, Fisher's exact test).(ABSTRACT TRUNCATED AT 250 WORDS)

A prospective study of 1094 consecutive adult patients undergoing coronary revascularization was undertaken to determine the effect of anesthetic technique on outcome. Patients received one of five primary techniques: high-dose fentanyl (greater than 50 micrograms/kg), moderate-dose fentanyl (less than 50 micrograms/kg), sufentanil (3-8 micrograms/kg), diazepam (0.4-1 mg/kg) with ketamine (3-6 mg/kg) or halothane (0.5-2.5% inspired concentration after thiopental induction). Supplemental inhalation anesthesia (enflurane, halothane, or isoflurane) was used in 60% of cases where the primary technique was intravenous based. Patients in the above anesthetic groupings had similar perioperative demographic and risk classifications. The overall incidence of postoperative myocardial infarction, postoperative low cardiac output state, and in-hospital death were 4.1, 5.6, and 3.1%, respectively. There were no significant differences in the incidence of these occurrences or in the incidence of serious pulmonary, renal, or neurologic morbidity or length of ICU stay among primary anesthetic techniques nor among supplemental inhalation agent groups. Multivariate discriminant analysis of this data suggests that a multitude of factors are significantly more important than anesthetic technique as determinants of outcome after coronary artery surgery.

Coronary air embolism (CAE) can occur after heart surgery whenever air is present in the left heart or proximal aorta. When CAE occurs, its sequelae can range from electrocardiographic changes of ischemia to severe myocardial dysfunction and cardiac arrest. Since N2O has been shown to have detrimental effects in the presence of coronary obstructions, as well as the tendency to enlarge air emboli, the authors tested the hypotheses that N2O would enhance the deleterious effects of CAE, and that discontinuing N2O at the time of CAE would minimize those effects. The effects of ventilation with and without N2O on the cardiac insult due to left anterior descending CAE (0.02 ml.kg-1) were studied in 27 swine. Global cardiovascular changes that occurred after CAE included decreases in cardiac output, systemic arterial and coronary perfusion pressure, and LV dP/dt, as well as increases in LVEDP. These parameters returned towards baseline over time when N2O was discontinued at the time of CAE. Maintenance of N2O in the inspired gas after CAE occurred was uniformly fatal within 2-4 min in this model. Regional myocardial ischemia was significantly greater in animals receiving N2O, as documented by: 1) a greater incidence of elevations of epicardial ST-segments exceeding 3 mm from baseline in embolized and non-embolized coronary artery distributions, 2) a greater incidence of dysrhythmias (greater than 6 PVCs.min-1), 3) longer duration of depression of coronary blood flow, 4) longer duration of post-ischemic coronary hyperemia, and 5) larger decreases with less recovery over time of regional myocardial lactate extraction.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of two different anesthetic techniques on postoperative cardiopulmonary events, fluid and vasopressor requirements, and overall intensive care unit (ICU) course were studied in patients undergoing elective myocardial revascularization (CABG) (N = 20) or single cardiac valve replacement (N = 20). Patients were randomized to receive either high-dose fentanyl (F, 75 microg/kg followed by 0.3 microg/kg/min) or diazepam-ketamine (0.8 mg/kg D and 2 mg/kg K followed by 0.07 mg/kg/h D and 1 mg/kg/h K). No significant differences in preoperative demographics, prebypass hemodynamics, ischemic crossclamp, or total cardiopulmonary bypass times were noted. Patients receiving F had lower systemic arterial pressures and vascular resistances and required more vasopressors during the first 12 hours postoperatively. They also had a more positive cumulative fluid balance at 24 and 48 hours postoperatively, despite a higher incidence of postoperative diuretic use in CABG patients receiving F. Rectal temperature was significantly higher at four and eight hours postoperatively in F patients. Time until arousal and length of ICU stay were significantly greater with F, although duration of intubation did not differ between anesthetic techniques. Although the data does not provide an explanation for these differences, it indicates that these two techniques produce quite different physiologic responses in the postoperative period following cardiac surgery. In summary, it was found that F for cardiac surgery was accompanied by increased postoperative fluid and vasopressor requirements with increased Qsp/Qt and longer ICU stays compared to diazepam and ketamine. This study suggests that some anesthetic techniques may provide less complicated and less costly postoperative courses than others, with the same outcome after cardiac surgery. Information on the postoperative effects of long-acting anesthetic agents is sparse and more studies of these effects and their mechanisms are necessary because they may affect patient management after cardiac surgery.

Postoperative hemorrhage remains a major cause of morbidity after cardiopulmonary bypass (CPB). Treatment remains empiric because of the need for immediate correction and the lack of availability of rapid intraoperative coagulation monitoring (except for ACT) at most institutions. Thrombelastography (TEG) and Sonoclot analysis (SCT) are measures of viscoelastic properties of blood which allow rapid intraoperative evaluation of coagulation factor and platelet activity as well as overall clot integrity from a single blood sample. Routine coagulation tests (RCT) including activated clotting time (ACT), prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen level (FIB), and platelet count (PLT) were determined and compared to TEG and SCT to assess which best predicted clinical hemostasis after CPB. Forty-two patients prospectively felt to be at high risk for excessive post-CPB bleeding had blood obtained for RCT, TEG, and SCT analysis before systemic heparinization and 30 min after protamine administration. Nine of 42 patients had excessive chest tube drainage, but no reoperations were required. After CPB, mean values for RCT were normal, but there were abnormalities in TEG and SCT parameters that reflect platelet-fibrin interaction. Both TEG and SCT were 100% accurate in predicting bleeding in these nine patients and, overall, both tests were significantly better predictors of postoperative hemorrhage than RCT. We conclude that viscoelastic determinants of clot strength may be abnormal after CPB and that SCT and TEG are, therefore, more useful than RCT for the detection and management of coagulation defects associated with CPB.

Orthotopic liver transplantation (OLT) often involves large blood loss and replacement, as well as administration of large amounts of blood products to correct coagulation defects. Renal free water excretion is often impaired in end-stage liver disease and not responsive to routine diuretic therapy, predisposing these patients to accumulation of extravascular lung water. The effects of the intraoperative use of continuous arteriovenous hemofiltration (CAVH) on cardiopulmonary and oxygen transport variables were studied in ten patients during and 24 hours after OLT. CAVH prevented increases in pulmonary shunt fraction while decreasing PEEP and FIO2 requirements. Pulmonary compliance was significantly higher after operation in patients receiving CAVH. Before surgical dissection, hemodynamic effects of CAVH were minimal. Postoperatively, patients having CAVH had lower cardiac filling pressures and more normal systemic vascular resistance than did patients not having CAVH. These data suggest that CAVH may be a useful intraoperative technique for patients with impaired renal function undergoing liver transplantation.

The effects of progressive blood loss on coagulation were studied in 87 adults (age 23-66 yr) undergoing a variety of operations under general anesthesia. None had preoperative alterations in coagulation or liver function and none were receiving anticoagulant or antiplatelet medication. Whole blood coagulation status was quantitated using thrombelastography (TEG). Blood samples for TEG were obtained 5 min before and 15 min after induction of anesthesia, after each increment of blood loss (EBL) equalling 5% of estimated blood volume (EBV), at the end of surgery, and 2 hr post-operatively. Patients with EBL exceeding 0.15 EBV were given packed red cells and crystalloid solution. Patients with EBL less than 0.15 EBV received only crystalloid. Thrombelastography analysis showed a trend toward increased coagulability with progressive blood loss. Two of four patients with 80% loss of EBV maintained normal to enhanced coagulation status, although the other two developed clinical and thrombelastographic evidence of coagulopathy. Thrombelastography allowed rapid intraoperative diagnosis and specific treatment of loss of platelet activity in the latter two patients. We conclude that during moderate to massive blood loss, use of supplemental fresh frozen plasma and/or platelets should be reserved for patients with documented defects in coagulation. Thrombelastography is useful for the detection and management of coagulation defects associated with intraoperative blood loss.

We examined the biostimulating effects of helium-neon laser radiation (HeNe; 632.8 nm), pulsed infrared laser radiation (IR; 904 nm), and the two combined on skin wound healing in New Zealand white rabbits. Seventy-two rabbits received either 1) no exposure, 2) 1.65 J/cm2 HeNe, 3) 8.25 J/cm2 pulsed IR, or 4) both HeNe and IR together to one of two dorsal full-thickness skin wounds, daily, for 21 days. Wound areas were measured photographically at periodic intervals. Tissue samples were analyzed for tensile strength, and histology was done to measure epidermal thickness and cross-sectional collagen area. Significant differences were found in the tensile strength of all laser-treated groups (both the irradiated and nonirradiated lesion) compared to group 1. No differences were found in the rate of wound healing or collagen area. Epidermal growth was greater in the HeNe-lased area compared to unexposed tissue, but the difference was not significant. Thus, laser irradiation at 632.8 nm and 904 nm alone or in combination increased tensile strength during wound healing and may have released tissue factors into the systemic circulation that increased tensile strength on the opposite side as well.

The short duration of epidural fentanyl has limited its direct comparison with epidural morphine in previous reports. The following study was performed of continuous postoperative epidural infusions at 5 ml/hr fentanyl 10 micrograms/ml (n = 59) or morphine 0.1 mg/ml (n = 48), both with bupivacaine 0.1%, in patients having cesarean sections. Postoperative evaluations included the frequency and magnitude of clinically evident respiratory depression, the adequacy of analgesia, nausea, pruritus, the ability to ambulate, and other side effects for 24 hours. Analgesia and the number of supplemental narcotic injections needed were similar in both groups. The incidence of nausea and pruritus was significantly less in the patients receiving fentanyl. No patient developed respiratory depression in either group. Patient and staff acceptance of the continuous epidural technique was excellent because there were only minor catheter-related problems associated with its use. It is concluded that continuous epidural fentanyl combined with bupivacaine offers excellent postoperative analgesia with minimal side effects.

Venous air embolism has been reported to occur during total hip arthroplasty. The incidence of venous air embolism, however, has not been previously studied in a large series using Doppler ultrasound and mass spectrometry. Seventy patients undergoing total hip arthroplasty were monitored for venous air embolism with precordial Doppler ultrasound, central venous catheter, end-tidal N2 and CO2 (mass spectrometry), and arterial blood gases (ABG). Changes in the monitored variables consistent with venous air embolism were noted in 57% by Doppler ultrasound, 9% by mass spectrometry, 4% by central venous catheter and 3% of the cases by ABG. A total of 77 Doppler ultrasound events were detected in 40 of the 70 patients studied. Hemodynamic changes consisting of either hypotension, defined as a greater than or equal to 20% decrease in mean arterial pressure (MAP), or cardiac dysrhythmia occurred during 43% of these events. The Doppler ultrasound was the only monitor that detected all cases of venous air embolism with concomitant hemodynamic changes. Air was aspirated from the central venous catheter during 10% of the detections of venous air embolism by Doppler ultrasound. Venous air embolism in total hip arthroplasty is a common event and may be responsible for hemodynamic changes previously ascribed to the use of methylmethacrylate cement. Routine monitoring with Doppler ultrasound appears warranted. The routine use of central venous catheterization may also be warranted.

Postoperative hemorrhage in patients undergoing open-heart surgery is a major cause of morbidity and mortality. Monitoring of coagulation in these patients has routinely involved the activated clotting time. Thromboelastography is currently used as a monitor of coagulation during liver transplantation. The thromboelastogram, by providing information on the interaction of all the coagulation precursors, gives more clinically useful information on coagulation than that available from the coagulation profile or the activated clotting time alone. This study was done to assess the usefulness of thromboelastography in open-heart surgery. Thirty-eight patients (29 undergoing coronary artery bypass grafting and 9 undergoing valve replacement) were studied with activated clotting time, thromboelastography, and coagulation profiles during three periods: before bypass, during bypass, and after protamine administration. Thromboelastography was a significantly better predictor (87% accuracy) of postoperative hemorrhage and need for reoperation than was the activated clotting time (30%) or coagulation profile (51%). Thromboelastography is easy to use and provides diagnostic data within 30 minutes of blood sampling.

Decompression sickness is caused by the production of tissue and blood stream inert gas bubbles. Perfluorocarbon emulsions (PFC) have enhanced O2 and N2 solubilities as well as a small particle size as properties. The effects of treatment with a PFC (FC-43) and 100% oxygen on decompression sickness were investigated in 24 Sprague-Dawley rats compressed to 6.8 ATA and rapidly decompressed. Survival in animals receiving PFC and 100% oxygen was significantly longer (P = 0.01) than in those receiving a 6% hetastarch (H) treatment. The PFC survivors at 24 h did not demonstrate any neurologic deficits, whereas the 1 H animal surviving at 24 h was ataxic and not eating. Those animals who died most often did so within minutes after decompression, suggesting a hemodynamic demise. We conclude that PFC treatment when coupled with 100% oxygen breathing provides both hemodynamic and neurologic protection from decompression sickness.

A functional and histologic examination of the effect of the continuous intrathecal administration of bupivacaine was made in five dogs. After a partial laminectomy at L5, a silicone rubber catheter was inserted into the subarachnoid space and advanced 10 cm cranially. A model 400 Infusaid pump, used for drug delivery, was placed in a subcutaneous pocket between the 13th rib and iliac crest. Drug infusions were individually adjusted and maintained at a concentration such that the animal just exhibited slight gait impairment. Daily bupivacaine doses ranged from 5.7-11.1 mg. Infusions were maintained for a period of 3-16 weeks. Light microscopic examination of spinal cord and roots revealed no abnormalities. A focal mononuclear cell infiltration of the leptomeninges was seen in two drug animals, as well as one catheter control animal. One of the 16-week animals had a residual limp upon drug removal. While we were not able to quantitatively assess the degree of sensory motor dissociation, the results of this study suggest that chronic intrathecal bupivacaine infusion through an implantable pump system may be a short-term alternative to intrathecal morphine in the control of cancer pain.

The cardiorespiratory effects of a nonlethal venous air embolism were studied in dogs in the presence of a perfluorocarbon emulsion (PFE). Prior to embolization, five dogs received 20 cc/kg of hydroxyethyl starch (6% HES) and five received PFE oxypherol (20% FC-43). Determinations of mean systemic arterial pressure (MAP), pulmonary artery pressure (PAP), left ventricular pressure (LVP), first and second derivatives of LVP with respect to time (dP/dt and Vmax), cardiac index (CI), stroke index, left and right ventricular stroke work index (LVSWI and RVSWI), PaCO2, PaO2, and venous admixture (Qs/Qt) were made before and then 1, 5, 10, and 30 minutes after placement of the venous air emboli (0.75 cc/kg/min for 5 minutes). After emboli were introduced, PaO2, MAP, LVSWI, dP/dt, Vmax, and CI decreased; the average decrease during the first 5 minutes was significantly less in the PFE group. Following introduction of venous air emboli, PAP, PaCO2, RVSWI, and Qs/Qt increased less in the PFE group than in the HES group, with statistical significance achieved at various times during the first 10 minutes after embolism. All parameters returned toward baseline values by 30 minutes in both groups. This study indicates that FC-43, when administered before venous air embolism, helps to attenuate some of the detrimental cardiorespiratory effects of the embolism.

Ten male mongrel dogs were treated in Phase I with tranylcypromine, 6 mg/kg IM b.i.d., for 21 days. Dogs were anesthetized at weekly intervals before, during, and up to four weeks after drug treatment with a combination of amylbarbital, 25 mg/kg, 1% enflurane in 70:30 N2O:O2 and fentanyl, 500 mcg. Bolus IV injections of norepinephrine, 0.1-0.6 mcg/kg, and ephedrine, 0.03-0.12 mg/kg were given while continuously recording arterial blood pressure, lead II of the ECG, heart rate, and rectal temperature. Awakening times were noted. In Phase II, the dogs were given imipramine, 25 mg/kg IM b.i.d., for 21 days. During Phase III, 14 days of tranylcypromine, 7 days of tranylcypromine plus imipramine, and 7 days of imipramine were administered. Anesthetic techniques were repeated in phases II and III. The fourth phase consisted of tranylcypromine injections, 6 mg IM b.i.d., and anesthesia with amylbarbital, 25 mg/kg, 2.5% enflurane in 70:30 N2O:O2. Vasopressor challenges were repeated during each phase of the study. Following induction of anesthesia and prior to fentanyl challenge, baseline blood pressures and heart rates did not differ from control in Phase I, II, and III of this study. Responses to norepinephrine during all of the tranylcypromine phases were not significantly different from control but ephedrine responses were prolonged, peaking by the second week of treatment. During Phase II, dysrhythmias occurred following norepinephrine and ephedrine with one lethality following norepinephrine, 0.2 mcg/kg. Responses to norepinephrine and awakening times were significantly greater during Phase II compared to Phase I. In Phase III, during the first week of combined therapy the responses to norepinephrine were significantly greater than any other week of this phase. During Phase IV, resting blood pressure and the ephedrine responses were significantly increased during tranylcypromine when the anesthesia regimen did not include fentanyl. These results suggest that during initial treatment with tranylcypromine or imipramine, cardiovascular responses to vasopressor challenges were predicted by the pharmacology of the antidepressant. During tranylcypromine phases, we did not observe exaggerated cardiovascular effects during anesthesia and vasopressor challenges as had been previously reported.

Liver transplantation procedures are being performed at an increasing number of hospitals throughout the United States. These procedures are challenging because of hemodynamic, metabolic, renal, and coagulation dysfunctions and may require prolonged periods of time for completion. Anesthesia departments are developing or managing teams of personnel to perform liver transplants. A survey was sent to directors of liver transplant anesthesia teams to investigate how teams were structured, compensated, and the impact of participation upon personnel involved. Thirty-nine centers were surveyed and 31 responded. The results showed an arithmetic doubling of cases for each of the last six years, most being performed at large medical centers (more than 759 beds) with populations served of 2 million or more. Cases were reported to average 13 hours in length and required a mean of five anesthesia personnel to complete. Compensation methods for work on a liver transplant team were variable; however, CRNAs and technicians received monetary reimbursement more frequently than physicians. Emotional responses of personnel were equally divided between favorable and unfavorable responses. Discriminate analysis showed that positive personnel attitudes were most closely tied to the presence of a protocol for breaks, call schedules, compensation, and the frequency of performing these cases. However, most protocols for personnel management were instituted in response to dissatisfaction. As the number of transplants per year increases, departments will need effective plans for personnel management to maximize departmental resources, increase research interest, and maintain personnel enthusiasm.

Previous studies have suggested that low-risk cardiac surgical patients may be safely managed without pulmonary artery catheterization (PAC). However, no prospective studies have determined whether PAC improves outcome in higher risk patients compared with that following central venous pressure (CVP) monitoring alone. The authors prospectively examined the incidence of and factors related to perioperative morbidity and mortality in 1094 consecutive patients undergoing coronary artery surgery managed with elective PAC (n = 537) or with CVP (n = 557). Perioperative risk factors and demographics that predict morbidity and mortality after cardiac surgery were used to quantify risk classification. Outcome was judged by length of ICU stay, occurrence of postoperative myocardial infarction, in-hospital death, major hemodynamic aberrations, and significant noncardiac systemic complications. No significant differences in any outcome variables were noted in any group of patients with similar quantitative risk classification managed with or without PAC, including those in the highest risk class. In addition, there were no significant differences in outcome among the 39 patients who would have been managed with CVP monitoring only, but who subsequently developed a clinical need for PAC based on the occurrence of serious hemodynamic events compared to patients who had PAC performed electively. This study suggests that PAC does not play a major role in influencing outcome after cardiac surgery, that even high-risk cardiac surgical patients may be safely managed without routine PAC, and that delaying PAC until a clinical need develops does not significantly alter outcome, but may have an important impact on cost savings.