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Biomedical subjects

A Baraka

Publications and source records attributed to A Baraka.

At least 109 records · Page 6Linked to original sources
PubMed1993

Vecuronium block in the myasthenic patient. Influence of anticholinesterase therapy.

The neuromuscular block of vecuronium was investigated in two myasthenic patients undergoing thymectomy. The first patient had no pre-operative anticholinesterase therapy, the second patient was given pyridostigmine 60 mg 4 hourly, continued until the morning of surgery. In the two patients, neuromuscular block of vecuronium was monitored by electromyography. The results suggest that the neuromuscular block of vecuronium may be decreased by pre-operative preparation of the myasthenic patient by pyridostigmine.

Adolescent↗
PubMed1993

Repeated doses of suxamethonium in the myasthenic patient.

The neuromuscular block of successive doses of suxamethonium 100 mg, monitored by electromyography, was investigated in a myasthenic patient (class IIB), undergoing thymectomy. The results suggest that successive doses of suxamethonium in the myasthenic patient are followed by a progressive prolongation of the neuromuscular block. This may be attributed to rapid desensitisation of the myasthenic endplate receptors and the rapid development of phase II block, as evidence by a progressive decrease of the T4/T1 ratio.

Adult↗
PubMed1993

The effect of perfusion flow on oxidative metabolism during cardiopulmonary bypass.

The influence of perfusion flow rate on whole-body oxygen consumption (VO2), central venous hemoglobin oxygen saturation (SVO2), and central venous arterial oxygen tension (PVO2) during hypothermic hemodilutional nonpulsatile cardiopulmonary bypass was investigated in 20 patients undergoing coronary artery bypass grafting. In 10 patients, the perfusion flow was 2.4 L.min-1 x m-2 (Group I), whereas a flow of 1.2 L.min-1 x m-2 was used in the other 10 patients (Group II). When the body temperature was 29.7 +/- 1.2 degrees C (Group I) and 29.6 +/- 0.8 degrees C (Group II), mixed venous and arterial blood were sampled simultaneously, and whole-body oxygen consumption was calculated. Data collected during hypothermia were compared with the corresponding values achieved after rewarming to 37 degrees C. In both groups, the whole-body oxygen consumption during hypothermia was lower by about 45% than the VO2 after rewarming. However, SVO2 during the low perfusion flow was not significantly different from SVO2 after rewarming, whereas the temperature-corrected PVO2 was significantly lower. In contrast, the high-perfusion flow provided luxury perfusion as evident by the high SVO2, and maintained the temperature-corrected PVO2 within the normothermic range. Thus, maintenance of the normothermic perfusion flow rate during moderate hypothermic hemodilutional cardiopulmonary bypass may provide a safety margin that may compensate for unexpected increase of oxygen consumption or decrease of oxygen delivery.

Aged↗
PubMed1993

Use of the self-inflating bulb for detecting esophageal intubation after "esophageal ventilation".

This present investigation tests the efficacy of the self-inflating bulb for detecting esophageal intubation after intentional "esophageal ventilation" to mimic gastric insufflation after bag-and-mask ventilation. In 72 anesthetized patients, the trachea and esophagus were intubated with identical tubes. The efficacy of the bulb was tested by a second anesthesiologist before and after the delivery of three breaths at a tidal volume of 300-350 mL each. The pressures generated by the bulb connected to esophageally placed tubes were measured in 10 patients. In all patients, the second anesthesiologist reported no reinflation of the bulbs when connected to esophageally placed tubes and instantaneous reinflation when connected to tracheally placed tubes, thus correctly identifying the location of each tube. The mean negative pressure generated when compressed bulbs were connected to esophageally placed tubes was 55.4 +/- 1.2 mm Hg before esophageal ventilation and 59.0 +/- 0.68 mm Hg after esophageal ventilation. We conclude that insufflation of the stomach as a result of esophageal ventilation, to the extent demonstrated in this study, does not interfere with the effectiveness of the bulb in differentiating esophageal from tracheal intubation.

Adult↗
PubMed1993

Anesthesia and myasthenia gravis.

Myasthenia gravis is an autoimmune disease, resulting from the production of antibodies against the acetylcholine receptors of the endplate. These antibodies reduce the number of active receptors, brought about either by functional block of the receptors, by increased rate of receptor degradation, or by complement-mediated lysis. In myasthenic muscles, the miniature endplate potential amplitude is decreased, and a large proportion of the endplate potentials are subthreshold. Repetitive nerve stimulation results in a decremental response. The disease is frequently associated with morphological abnormalities of the thymus. In young patients, thymic hyperplasia is common while thymoma is more frequent in elderly patients. Medical treatment of myasthenia gravis aims at improving of neuromuscular transmission by anticholinesterases, suppressing the immune system by corticosteroids and immunosuppressents, or by decreasing the circulating antibodies by plasmapheresis. Adults with generalized myasthenia should have a transsternal thymectomy. A balanced technique of general anaesthesia which includes the use of muscle relaxants can be safely used, provided neuromuscular transmission is monitored. Myasthenic patients are sensitive to nondepolarizing relaxants but intermediate-acting nondepolarizing relaxants such as atracurium and vecuronium are eliminated rapidly, and can be titrated to achieve the required neuromuscular block that can be completely reversed at the end of surgery. Postoperatively, ventilatory support may be required in high-risk patients. Also, medical treatment may be maintained, tapered or discontinued depending on the outcome of surgery. Thymectomy benefits nearly 96% of patients, 46% develop complete remission and 50% are asymptomatic or improve on therapy.

Adolescent↗
PubMed1993

Foot infections in diabetics: the antibiotic choice.

The authors studied 59 diabetics with foot infections to determine the organisms responsible and the sensitivity to antibiotics. All infections were polymicrobial (aerobic and anaerobic). On average 3.2 isolates per culture were obtained from the depth of the infection. The commonest organisms in order of frequency were: Staphylococcus aureus, beta-hemolytic streptococci, Proteus sp., Bacteroides sp., enterococci, Klebsiella sp. and Pseudomonas aeruginosa. A combination of piperacillin and cloxacillin is recommended as initial therapy for foot infections in diabetic patients because it was found to be effective for 73% of the causative microorganisms.

Adult↗
PubMed1992

Onset of vecuronium neuromuscular block is more rapid in patients undergoing caesarean section.

This investigation was carried out in ten patients undergoing elective Caesarean section and the results were compared with those of a control group of ten nonpregnant females of the same age group. The study investigated the onset of vecuronium neuromuscular block and the conditions of tracheal intubation when ketamine (1.5 mg.kg-1)-vecuronium 100 micrograms.kg-1) sequence was used for rapid-sequence induction of anaesthesia. The ulnar nerve was stimulated supra-maximally at the wrist with train-of-four stimuli every 20 sec, and the electromyographic response of the adductor pollicis muscle was displayed. The onset of 50% neuromuscular block as monitored by electromyography was shorter in the Caesarean group (80 +/- 30 sec) than in the control group (144 +/- 43 sec). The conditions of intubation at 50% block were adequate in both groups. Also, the onset of 90% block was shorter in the Caesarean group. The time of recovery to T1/control ratio of 25% was longer in the Caesarean group (46 +/- 10 min) than in the control patients (28 +/- 10 min). The results show that administration of vecuronium according to body weight results in a more rapid onset and delayed recovery of neuromuscular block in pregnant women undergoing Caesarean section than in the nonpregnant control patients.

Adult↗
PubMed1992

Anaesthesia and myasthenia gravis.

Myasthenia gravis is an autoimmune disease, resulting from the production of antibodies against the acetylcholine receptors of the endplate. These antibodies reduce the number of active receptors, brought about either by functional block of the receptors, by increased rate of receptor degradation, or by complement-mediated lysis. In myasthenic muscles, the miniature endplate potential amplitude is decreased, and a large proportion of the endplate potentials are subthreshold. Repetitive nerve stimulation results in a decremental response. The disease is frequently associated with morphological abnormalities of the thymus. In young patients, thymic hyperplasia is common while thymoma is more frequent in elderly patients. Medical treatment of myasthenia gravis aims at improving of neuromuscular transmission by anticholinesterases, suppressing the immune system by corticosteroids and immunosuppressants, or by decreasing the circulating antibodies by plasmapheresis. Adults with generalized myasthenia should have a trans-sternal thymectomy. A balanced technique of general anaesthesia which includes the use of muscle relaxants can be safely used, provided neuromuscular transmission is monitored. Myasthenic patients are sensitive to nondepolarizing relaxants but intermediate-acting nondepolarizing relaxants such as atracurium and vecuronium are eliminated rapidly, and can be titrated to achieve the required neuromuscular block that can be completely reversed at the end of surgery. Postoperatively, ventilatory support may be required in high-risk patients. Also, medical treatment may be maintained, tapered or discontinued depending on the outcome of surgery. Thymectomy benefits nearly 96% of patients, 46% develop complete remission and 50% are asymptomatic or improve on therapy.

Adolescent↗