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Biomedical subjects

R A Dyer

Publications and source records attributed to R A Dyer.

27 records · Page 2Linked to original sources
PubMed1992

Epidural lidocaine with sufentanil and epinephrine for abdominal hysterectomy under general anaesthesia: respiratory depression and postoperative analgesia.

The purpose of this investigation was to compare the analgesic actions and side-effects of a 50 micrograms epidural bolus of sufentanil and 50 micrograms epinephrine, with a control group receiving saline and epinephrine. The method employed was a prospective, randomised, double-blind trial involving 40 ASA I or II patients for total abdominal hysterectomy. All received 1.5% lidocaine with 1/200,000 epinephrine epidurally before operation, until a block to T4 was established. Patients were anaesthetised, their tracheas were intubated, and they were allowed to breathe spontaneously before administration of the test drug. Results showed that sufentanil prolonged the duration of local anaesthesia (198 +/- 35 min vs 174 +/- 29 min; P less than 0.05), and of analgesia (288 +/- 85 min vs 188 +/- 42 min; P less than 0.01). There was an increase in somnolence in the sufentanil group (9/20 vs 2/20; P less than 0.05). Glycopyrollate was given to 11/20 patients in the sufentanil group vs 1/20 in the control group (P less than 0.01) following bradycardia and hypotension. Clinical respiratory depression occurred in the sufentanil group; 5/20 patients required controlled ventilation following apnoea greater than 20 sec. It is concluded that epidural sufentanil causes considerable cardiorespiratory depression in the setting of general anaesthesia, and should be used with caution in the spontaneously breathing, anaesthetised patient.

Adult↗
PubMed1992

Comparison of the frequency spectra of surface electromyographic signals from the soleus muscle under normal and altered sensory environments.

The vestibular, proprioceptive and visual senses of the body are all affected by alterations of the normal sensory environment during weightlessness. This study was designed to observe muscle activation characteristics when a single component of the sensory environment was altered. Partially immersing a subject in a water pool provided a buoyant force upon the lower body, "unloading" the muscles, similar to the effect on the muscles in weightlessness. Surface EMG from the soleus was obtained during the performance of a constant-force isometric contraction. The mean and median characteristic frequencies were calculated from the power spectrum of each trial. Six of ten subjects showed a difference in the characteristic frequencies between the two environments. It appears that for some individuals there are changes in muscle activation characteristics due to influences of the proprioceptive system when exposed to an altered sensory environment.

Adult↗
PubMed1990

Postoperative pain control with a continuous infusion of epidural sufentanil in the intensive care unit: a comparison with epidural morphine.

A prospective, randomized, double-blind trial was conducted to compare the analgesic actions and side effects of sufentanil continuously infused (5 micrograms/h) into the lumbar epidural space (L2-3) with those of an infusion of lumbar epidural morphine (0.5 mg/h). Forty patients admitted to an intensive care unit after elective major abdominal surgery participated over a varying period of 24-40 h. Post-operative pain was treated with an epidural bolus of either sufentanil (50 micrograms) or morphine (5 mg), followed by a continuous infusion of the same opiate. The quality of pain relief was similar in each group. The sufentanil group had a more rapid onset of analgesia. The incidence of nausea and vomiting, pruritus, and drowsiness was similar in the two groups. In spontaneously breathing patients there were no respiratory complications requiring treatment. Forced vital capacities were statistically significantly better during the first 1-4 h with sufentanil.

Adult↗
PubMed1987

Delta-like toxin produced by coagulase-negative staphylococci is associated with neonatal necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) is a serious neonatal disorder of uncertain cause, although fecal bacteria have been implicated in some outbreaks. We examined coagulase-negative staphylococci (CONS) as possible etiologic agents. In our unit, CONS colonized the bowels of most infants studied, including 46% of 70 NEC cases (mean concentration, 10(9.1) CFU/g of stool). Over 90% of tested isolates produced a hemolysin resembling delta toxin of Staphylococcus aureus. Toxin purified from a NEC-associated isolate of Staphylococcus epidermidis resembled reference delta toxin from S. aureus in size, biologic properties, and antigenicity. This delta-like toxin was enteropathic, causing mucosal necrosis and hemorrhage in injected loops of the bowels of infant rats. Adjacent, nonexposed bowel remained normal, as did loops injected with lecithin-neutralized toxin. Using a new enzyme-linked immunosorbent assay (ELISA), we detected delta-like toxin in the stools of 11 of 35 infants colonized with CONS positive for delta-like toxin (Tox+). Positive tests were strongly associated with NEC. Of 18 cases with Tox+ CONS, 10 were positive (56%), whereas only 1 of 17 control infants so colonized was positive (6%, P = 0.002). In NEC patients, the mean fecal toxin concentration was 1,012 ng/g. Toxicity to fibroblasts was demonstrable in filtrates of each of six ELISA-positive samples tested but was absent in all five ELISA-negative samples tested. We conclude that delta-like toxin is elaborated in the bowels of some infants with Tox+ CONS, and its association with NEC suggests that such CONS are enteropathic. In our unit, this mechanism was apparent in 23% of 44 recent cases of endemic NEC.

Bacterial Toxins↗
PubMed1986

Myocardial tissue characterization using pattern recognition procedures on backscattered ultrasonic signals.

Pattern recognition techniques were applied to backscattered signals obtained in vitro from normal and abnormal canine and human heart samples. Orthogonal transforms, in conjunction with the variance criterion, comprised the feature extractors. The minimum-distance (MD) and nearest-neighbor (NN) rules were used as classification. When the MD rule was used, the magnitude of the DFT gave the best performance for both canine and human samples. When the NN rule was used, all the transforms performed comparably. The classification performances were improved for both species when the NN rule was used with feature extractors containing phase information.

Animals↗
PubMed1985

Adult respiratory distress syndrome associated with miliary tuberculosis.

Three patients with respiratory failure resulting from miliary tuberculosis had a characteristic clinical presentation that included a long history of a prominent cough, dyspnea, weight loss, tachycardia, tachypnea, pulmonary adventitious sounds, and hepatomegaly. Hematologic investigation showed a normal white cell count with marked left shift in the morphology of white cells in all three patients, and evidence of disseminated intravascular coagulation in one patient. In only one patient was the initial sputum positive for acid-fast bacilli; in the others, invasive diagnostic procedures including lumbar puncture, bone marrow trephine, and open-lung biopsy were necessary for diagnosis. Miliary tuberculosis should be suspected in patients with adult respiratory distress syndrome of unknown etiology. Simple diagnostic procedures such as sputum, bronchial brushings, and urine examination should be followed by bone marrow trephine, liver biopsy, transbronchial lung biopsy, and lumbar puncture if physical signs of meningitis are present.

Adult↗
PubMed1984

The adult respiratory distress syndrome bronchogenic pulmonary tuberculosis.

In three cases of pulmonary tuberculosis associated with the adult respiratory distress syndrome the clinical features, which were similar to those of patients with miliary tuberculosis and adult respiratory distress syndrome, included a history of cough, fever, and dyspnoea on effort, and the physical signs of fever, tachypnoea, pulmonary adventitious sounds, tachycardia, and hepatomegaly. In these cases the radiological features, though suggestive of diffuse pulmonary oedema, were more prominent on the side in which the cavitatory lesion appeared. The diagnosis of tuberculosis was made easily from direct examination of sputum. Despite early ventilatory support and antituberculous therapy, two of the three patients died. Postmortem examination of the lungs in these cases showed evidence of acute alveolar damage (loss of type 1 pneumocytes and the presence of hyaline membranes within alveolar ducts) and of chronic alveolar damage (interstitial and alveolar fibrosis).

Adult↗
PubMed1977

Effects of ethionine and phenobarbital on the phosphatidylcholines of rat liver.

The diglyceride species of phosphatidylcholines from livers of male rats after treatment of the animals with ethionine (1 mg/g divided among 4 doses 2 hr apart), phenobarbital (80 mg/kg each day for 3 days), or a combination of the two drugs were determined using gas chromatography. Ethionine treatment greatly elevated the diene species (significant at the 0.005 level for 34:2 and 0.001 level for 36:2). Phenobarbital treatment had no significant effect on the quantity of 34:2 but slightly increased that of 36:2 (significant at the 0.05 level). Both drugs caused relative decreases in the quantities of 38:4 (significant at the 0.001 level for ethionine and at the 0.01 level for phenobarbital). Ethionine decreased the content of 36:4 (significant at the 0.01 level) while phenobarbital treatment did not produce a significant effect on this fraction. Thus, while ethionine produced marked effects on the quantities of the various molecular species, the effects of phenobarbital were less dramatic. Combined treatment with both drugs generally produced levels of species similar to those produced by ethionine alone.

Animals↗