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Biomedical subjects

R C Cork

Publications and source records attributed to R C Cork.

54 records · Page 3Linked to original sources
PubMed1982

Doxepin effects on chronic pain, depression and plasma opioids.

Thirty patients with chronic low back or cervical pain combined with clinical depression were studied in a six-week, randomized, double-blind comparison of doxepin and placebo. Dependent variables included Hamilton Depression Scores, the Clinical Global Assessment Scale, and Profile of Mood States (POMS), and subjective ratings (visual analogue scales) of pain severity, percent of time pain felt, and effect of pain on activity, muscle tension, sleep, mood, and analgesic drug consumption. Plasma levels of doxepin, desmethyldoxepin, beta-endorphin, and enkephalin-like activity were also measured. Significant improvements in the doxepin-treated group compared to the placebo group were seen in Hamilton scores, Global Assessment Scale, Profile of Mood States, percent of time pain felt, and effect of pain on sleep, muscle tension, and mood. Some improvement was observed after 1 week, although most improvement occurred at 6 weeks, when the mean doxepin dose was 2.5 mg/kg and plasma doxepin and desmethyldoxepin averaged 70 ng/ml. Nonspecific enkephalin-like activity (but not beta-endorphins) increased for the treatment group and decreased for the placebo group. The efficacy of doxepin compared with that of placebo was thus documented in several depressive and pain parameters, indicating that doxepin is a valuable treatment for patients with chronic pain and depression.

Adult↗
PubMed1982

Inaccuracy of liquid crystal thermometry to identify core temperature trends in postoperative adults.

In 71 adult postsurgical patients, simultaneous measurement of core (tympanic membrane) and shell (liquid crystal adhesive temperature strip) cutaneous temperature was assessed on admission and every 15 minutes throughout the recovery room stay. Tympanic membrane sensors were inserted into the ear and adhesive temperature strips were applied to the forehead. Although temperature strip temperatures on admission to the recovery room were correlated significantly with tympanic membrane temperatures on admission to the recovery room (r = 0.61, p less than 0.001), subsequent readings 15, 30, 45, and 60 minutes after admission demonstrated decreasing correlation coefficients. Moreover, changes in temperature strip temperatures over the first 15, 30, and 45 minutes of monitoring in the recovery room did not correlate significantly with changes in tympanic membrane temperatures over the same time period. These data suggest that shell temperature (temperature strip) is not a reliable or valid trend indicator of core temperature (tympanic membrane) in postanesthetic adults.

Adolescent↗
PubMed1982

Effects of dilution, pressure, and apparatus on hemolysis and flow rate in transfusion of packed erythrocytes.

The purpose of this prospective, randomized study was to measure both the independent and interactional effects of dilution, pressure, and apparatus on flow rates and hemolysis during rapid administration of erythrocytes. Administration of undiluted erythrocytes increased the concentration of plasma-free hemoglobin by as much as 270% per unit under certain conditions. Transfusion flow rates for packed red blood cells were found to be determined by dilution, pressure, and apparatus and varied by as much as 450%. No significant correlation was found between flow rate and hemolysis. Regardless of the external bag pressure applied or the transfusion apparatus used, packed erythrocytes should be diluted (with at least 100 ml of normal saline) to decrease hemolysis and increase flow rate.

Blood Transfusion↗
PubMed1981

General anesthesia for morbidly obese patients--an examination of postoperative outcomes.

Specific postoperative outcomes were assessed in 67 morbidly obese subjects who received general anesthesia for gastric stapling. Each patient was randomly assigned to receive N2O:O2 combined with fentanyl (n = 20), enflurane (n = 24), or halothane (n = 23). Time from last skin stitch until the patient opened eyes on command was significantly less for the fentanyl group (3.0 +/- 0.7 min) than for the enflurane group (13.2 +/- 1.9 min) or the halothane group (17.4 +/- 2.9 min) with P less than 0.05. However, no significant differences in time from last skin stitch to extubation were noted among the fentanyl (16.2 +/- 7.4 min), enflurane (15.2 +/- 1.6 min), and halothane (21.6 +/- 5.8 min) groups (P greater than 0.05). Recovery room (RR) admission temperatures were similar for the three groups: fentanyl, 36.1 +/- 0.1 degrees C; enflurane, 35.7 +/- 0.2 degrees C; and halothane, 36.0 +/- 0.1 degrees C (P greater than 0.05). Total RR time was not significantly different: fentanyl, 108 +/- 6 min, enflurane, 118 +/- 4 min; and halothane, 112 +/- 10 min (P greater than 0.05). In addition, no difference in RR and 24-hour postoperative narcotic (meperidine) requirements was demonstrated among the anesthetic groups. These data suggest that increased lipid solubility of volatile anesthetics (halothane or enflurane) produces neither delayed awakening nor prolonged recovery time in morbidly obese subjects. Considering the early (24 hour) postoperative outcomes studied, there is little to commend one general anesthetic technique over another in the obese subset of the population.

Adult↗
PubMed1981

The effect of massive weight loss on arterial oxygenation and pulmonary function tests.

Pulmonary function tests (PFTs) and arterial oxygenation were studied 24 hours preoperatively and again at varying times (5 to 20 months) during the postoperative weight loss of 37 morbidly obese patients. Among PFTs, expiratory reserve volume (ERV) demonstrated the most significant (P less than 0.001) improvement with weight loss. No clinically relevant differences were found after weight loss in FEV1, FVC, or MMEF. In 11 patients whose arterial blood gases were sampled before and after weight loss, a significant correlation was demonstrated between change in ERV and change in Pao2 (r = 0.59, P less than 0.05) and P(A-a)o2 (r = 0.76, P less than 0.01). When weight loss is expressed as either change in body mass index (delta BMI) or as a change in percent of ideal weight (delta wt), there existed a weight loss threshold for improvement in arterial oxygenation. A delta BMI of greater than 20 or a delta wt more than 100 per cent resulted in a significant improvement in Pao2 (P less than 0.01) or P(A-a)o2 (P less than 0.05). These data suggest that morbidly obese patients do not meaningfully improve FEV1, FVC, or MMEF with massive weight loss. However, there is a significant improvement in ERV that directly correlates with improvement in both Pao2, and P(A-a)o2.

Adult↗
PubMed1981

Does evidence of reductive halothane biotransformation correlate with hepatic binding of metabolites in obese patients?

Covalent binding of fluorinated anesthetic metabolites was measured using intraoperative liver biopsies obtained from 48 morbidly obese patients randomly assigned to receive N2O-O2 combined with either fentanyl, enflurane, or halothane. No difference in binding was found between anesthetic groups. In addition, preoperative and postoperative levels of serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) did not differ among three groups of patients. However, hepatic organic fluoride binding significantly correlated with peak serum ionic fluoride in patients given halothane (p 0.001, r = 0.68). Thus, the fluorinated metabolites binding assay is a reliable index of reductive halothane metabolism. Possible application of this assay to aid in the diagnosis of postoperative liver dysfunction is suggested.

Adult↗
PubMed1981

Postoperative hypothermia in adults: relationship of age, anesthesia, and shivering to rewarming.

Frequency, magnitude, and duration of hypothermia (core body temperature less than 36.0 C) in the recovery room (RR) were determined in 198 adults. In addition, the influence of age, anesthetic technique, and shivering on the rewarming process was assessed. Tympanic membrane temperatures were recorded on admission to the RR and every 15 minutes thereafter until discharge from the RR. Sixty percent of the subjects had temperatures less than 36.0 C on admission to the RR. Elderly subjects (greater than or equal to 60 yr) had lower RR admission and discharge temperatures and experienced longer duration of hypothermia than did younger patients. General anesthesia was associated with a significantly more rapid rate of increase in postoperative temperature and a shorter duration of hypothermia than was regional anesthesia. The incidence of shivering and the incidence of hypothermia were significantly related 30 and 45 minutes after admission to the RR. Duration of hypothermia varied with different operative procedures.

Adolescent↗
PubMedDate not supplied

Leak rate of latex gloves after tearing adhesive tape.

Anesthesiologists use latex gloves to provide barrier protection against infectious disease or contamination while providing anesthetic services. The performance of these services often involves tearing tape. The purpose of this study was to test the effect of tearing adhesive tape on permeability of latex examination gloves and to test the effect of an adhesive-sparing moisturizing cream on permeability of latex gloves used to tear adhesive tape. In a blinded, randomized, controlled laboratory experiment, 48 nonsterile latex examination gloves (24 pairs) were randomized to 1 of 2 groups. Adhesive-sparing moisturizing cream, 0.1 mL, was applied to 12 glove pairs; the remaining 12 pairs served as controls. Each of the 24 pairs of gloves were used to tear five 4-cm strips of cloth adhesive tape from a standard 1 1/2-inch roll. After initial inspection for obvious tears, each glove was tested for leaks using the watertight test as specified by the American Society for Testing and Materials (ASTM). Data recorded included the identity of the investigator tearing tape, number of holes initially observed, number of holes observed from the ASTM test, location of holes, glove classification as right or left hand, and treatment group. Based on the study, the authors concluded that health care providers who tear adhesive tape while wearing latex gloves should be aware that there is a high probability that the gloves no longer form a protective barrier and that adhesive-sparing moisturizing cream applied before tape is torn increases barrier protection.

Double-Blind Method↗
PubMedDate not supplied

Effect of patient-controlled sedation on recovery from ambulatory monitored anesthesia care.

Patient-controlled sedation (PCS) with propofol has been shown to be an effective means of conscious sedation during monitored anesthesia care. The purpose of this study was to assess both the intraoperative conduct and postoperative recovery of patients receiving propofol for conscious sedation, randomized to either PCS or anesthetist-controlled sedation (ACS). Forty-three patients scheduled for outpatient procedures requiring monitored anesthesia care were randomized to PCS or ACS. Both groups received an initial bolus of propofol 0.5 mg/kg and fentanyl 1 microgram/kg i.v., followed by an identical background infusion of propofol 50 micrograms/kg per minute. Subsequent doses of propofol 30 mg i.v. were either self-administered (PCS) or administered at the discretion of the anesthetist (ACS). Variables measuring hemodynamics, ventilation, saturation, and level of sedation were measured at baseline, after initial bolus of propofol and fentanyl, after skin incision, at last stitch, at admission to recovery, and 1 hour later. More propofol was used by the PCS group (P < 0.05). Finger-tapping was slower and responsiveness scores were lower in the PCS group at the end of the procedure (P < 0.05). More patients in the PCS group required oxygen supplementation (saturation < 90%) on admission to recovery (P < 0.05). At 1 hour after recovery admission, however, there were no differences between groups. These results indicate that when patients determine their own sedation, they are more sedated at the end of a procedure than when the anesthetist determines the level of sedation.

Adult↗
PubMedDate not supplied

Acute effects of dobutamine and isoproterenol after implantation of a total artificial heart.

The hemodynamic effects of dobutamine and isoproterenol infusions were studied in five Holstein calves 1 day before and 2 days after the implantation of a Jarvik-7 total artificial heart (TAH). Cardiac output was decreased, and systemic vascular resistance (SVR) and pulmonary vascular resistance were increased after TAH implantation. Administration of dobutamine before TAH implantation caused an increase in heart rate, and discontinuation of dobutamine decreased cardiac output. Administration of dobutamine after TAH implantation caused decreases in mean arterial pressure and SVR. Isoproterenol increased heart rate and cardiac output and decreased SVR before TAH implantation. Isoproterenol produced no significant hemodynamic effects after TAH implantation. These results describe the hemodynamic effects that could be expected from normal clinical infusions of these drugs in the patient who is supported by the TAH as a bridge to heart transplantation; these results are of additional interest in that they describe the peripheral effects of the two agents independent of cardiac effects.

Animals↗
PubMedDate not supplied

Analysis of risk factors for acute allograft rejection after heart transplantation.

The diagnosis of cardiac allograft rejection is currently based on endomyocardial biopsy and histologic evaluation. Since the introduction of cyclosporine, cardiac biopsy has been recognized as the only reliable method of diagnosis. From July 1985 to June 1986, 22 transplant patients were studied during the early posttransplant period to evaluate other characteristics of allograft rejection. The immunosuppressive protocol included cyclosporine, azathioprine, prednisone, and prophylactic rabbit antithymocyte globulin. Acute rejection was established by standard histologic criteria. Twenty-four positive and 123 negative biopsy findings were obtained. Clinical variables (age, sex, immunosuppressive regimen, cyclosporine dosage, ECG voltage), biologic variables (level of cyclosporine, white blood cells, blood urea nitrogen, creatinine, bilirubin, prolactin, urinary polyamines, blood type, HLA typing), and immunologic variables (T-cell subsets) were analyzed in regard to the histologic diagnosis of acute rejection. Four variables (WBC, prolactin, total urinary polyamines, N-acetyl putrescine) were found to have a significant univariate association with acute rejection. These variables were studied by multivariate discriminant analysis. The only factors found to have independent predictive value for acute rejection were prolactin and N-acetyl putrescine peaks occurring before acute rejection. When we used these factors, a discriminant function correctly predicted acute rejection episodes, as well as negative biopsy results, in 74% of the cases in this group of patients.

Biopsy↗
PubMedDate not supplied

Indexes of hemolysis in human recipients of the Jarvik-7 total artificial heart: a cooperative report of fifteen patients.

The degree of red cell destruction in human recipients of the total artificial heart has not previously been described. Fifteen patients implanted with a Jarvik-7 total artificial heart for either temporary or permanent heart replacement were reviewed. Clinically significant elevations of plasma free hemoglobin and serum lactate dehydrogenase were demonstrated in patients receiving the standard (100 ml) Jarvik-7 containing Medtronic-Hall valves and powered by pulses of compressed air delivered at a dP/dT of 6000 mm Hg/sec to 8000 mm Hg/sec. Reduction of the dP/dT by drive unit modification greatly reduced the plasma free hemoglobin and lactate dehydrogenase in subsequent patients. Introduction of the smaller (70 ml) total artificial heart was not associated with greater hemolysis once dP/dT had been reduced. With the current driver delivering systolic pulses at less than 4500 mm Hg/sec, both size hearts are free of clinically relevant hemolysis. In addition, it appears that attempts to eliminate hemolysis completely by lowering heart rates, cardiac outputs, or driving pressures are potentially dangerous. The eventual development of embolic cerebrovascular accidents is associated statistically with heart rates below 80 beats/min. These data reassure implanting physicians that the updated Jarvik-7 total artificial heart system does not induce worrisome hemolysis. In addition, this study has uncovered a link between eventual cerebrovascular accident and low heart rate, implying that purposeful application of heart rates around 100 beats/min may provide a significant margin of protection against cerebrovascular accident during implantation.

Adult↗