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Biomedical subjects

N J Joseph

Publications and source records attributed to N J Joseph.

25 records · Page 2Linked to original sources
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↗
PubMed1991

Hemodynamic responses to pancuronium and vecuronium during high-dose fentanyl anesthesia for coronary artery bypass grafting.

The hemodynamic and electrocardiographic (ECG) effects of pancuronium and vecuronium were compared during high-dose fentanyl anesthesia for coronary artery bypass grafting (CABG) surgery. Forty-eight morphine-scopolamine premedicated patients scheduled for elective CABG were anesthetized with fentanyl (100 micrograms/kg) in divided doses, and either of two muscle relaxants, pancuronium (n = 26; 0.10 mg/kg) or vecuronium (n = 22; 0.09 mg/kg). Hemodynamic data, blood gas samples, and ECG tracings were obtained at the following intervals: (1) control; (2) prior to intubation; (3) 1 minute after intubation; (4) prior to sternotomy; and (5) 1 minute after sternotomy. In the pancuronium group, heart rate (HR), cardiac index (CI), and rate-pressure product (RPP) were increased after induction of anesthesia and following intubation. Eleven patients (42.3%) displayed ischemic ST segment changes. Four patients in this group developed tachycardia and hypertension to an extent requiring pharmacological intervention. Vecuronium-treated patients displayed no increases in HR, MAP, and RPP, and a decrease in CI. Only one patient (5.6%) developed evidence of ischemic ECG changes. Four patients in the vecuronium group, all receiving preoperative beta-blocker therapy, became hypotensive and bradycardic after the induction of anesthesia. The present investigation confirms the increased incidence of myocardial ischemia during high-dose fentanyl-pancuronium anesthesia. Although vecuronium was associated with fewer myocardial ischemic changes, the occurrence of bradycardia and hypotension in some patients receiving preoperative beta-adrenergic blocking drugs remains a concern.

Anesthesia, Intravenous↗
PubMed1991

Positive end-expiratory pressure increases intraocular pressure in cats.

BACKGROUND AND METHODS: The purpose of the present study was to examine the effect of various levels of positive end-expiratory pressure on intraocular pressure in cats. Fourteen healthy adult cats (2.6 to 3.7 kg) without evidence of ocular disease were anesthetized with pentobarbital, paralyzed, and placed on mechanical ventilation. Direct continuous measurements of heart rate (HR), mean arterial pressure (MAP), CVP, CSF pressure, and intraocular pressure were recorded at zero end-expiratory pressure, and at 5, 10, and 15 cm H2O positive end-expiratory pressure, applied in random order. MAIN RESULTS: There were no significant changes in pHa, Paco2, HR, MAP, hematocrit, and temperature. Intraocular pressure increased significantly from 17 (during zero end-expiratory pressure) to 20 mm Hg at 10 cm H2O positive end-expiratory pressure; at 15 cm H2O positive end-expiratory pressure, intraocular pressure increased significantly to 21 mm Hg. CVP and CSF pressure increased significantly in parallel with intraocular pressure at 5, 10, and 15 cm H2O positive end-expiratory pressure. CONCLUSIONS: We speculate that similar responses occur in man, and may be undesirable in patients with already increased intraocular pressure, when higher levels of positive end-expiratory pressure are used.

Animals↗
PubMed1991

Hemodynamic responses to endotracheal extubation after coronary artery bypass grafting.

After coronary artery bypass grafting (CABG) surgery, patients may remain at risk for myocardial ischemia and infarction and ventricular dysrhythmias. The hemodynamic responses to endotracheal extubation and the efficacy of intravenous lidocaine pretreatment were studied after CABG surgery and overnight mechanical ventilation. Twenty-five patients were divided into two groups: group 1 (n = 13) patients who had tracheal extubation after pretreatment with a placebo; group 2 patients who received lidocaine (1 mg/kg IV) before tracheal extubation. Hemodynamic data, electrocardiographic tracings, and arterial blood gases were obtained before tracheal extubation, during suctioning, and 1, 5, and 20 min after tracheal extubation. Group 1 patients displayed significant increases in heart rate, arterial blood pressure, rate-pressure product, right atrial pressure, and cardiac index during suctioning and within 1 min of tracheal extubation, returning to preextubation level by 5 min. There were no significant changes in pulmonary and systemic resistance indices. Hemodynamic changes in group 2 patients were similar to those in group 1. Both in the absence and presence of lidocaine, tracheal extubation caused hemodynamic responses that were small in magnitude and brief in duration. These responses were not associated with electrocardiographic or enzymatic evidence of myocardial ischemia or infarction, or with ventricular dysrhythmias. Compared with the well-documented hemodynamic responses to tracheal intubation, we found that extubation of the trachea after CABG surgery was associated with less pronounced responses. This may be related to avoidance of laryngoscopy and possibly accommodation to the endo-tracheal tube. These modest hemodynamic responses of extubation of the trachea after CABG surgery were not modified by intravenous lidocaine.

Coronary Artery Bypass↗
PubMed1990

Contrast media adversely affect oxyhemoglobin dissociation.

Effects of ionic (Hypaque-76) and nonionic (Isovue-370 and Omnipaque-350) contrast media on oxyhemoglobin dissociation of normal human red blood cells were evaluated. In series 1, 4-mL venous blood samples were obtained from 15 normal human volunteers. One blood sample served as control, and 1 mL of either of the three contrast media was added in vitro to the other 4-mL blood samples. P50 values were estimated from the linear portion of the oxyhemoglobin dissociation curve obtained by tonometry. Determinations of P50 were performed at either pH 7.4 or 7.2. At pH 7.4, P50 in the absence of contrast media was 26.3 +/- 0.4 mm Hg (mean +/- SEM). The contrast media caused comparable decreases in P50 from this value (Hypaque-76, 20.0 +/- 0.5 mm Hg; Omnipaque-350, 21.6 +/- 0.4 mm Hg; Isovue-370, 20.7 +/- 0.4 mm Hg). Reducing pH to 7.2 in the absence of contrast media increased P50 to 33.3 +/- 1.0 mm Hg, evidence of the Bohr effect. The presence of contrast media either completely abolished (Hypaque-76 and Omnipaque-350) or markedly attenuated (Isovue-370) this effect. In series 2 (five patients), blood samples were withdrawn from the external iliac artery during injection of Isovue-370 (60-78 mL) into the proximal abdominal aorta to evaluate peripheral vascular disease. Measurement of P50 of these samples yielded findings consistent with those of series 1. The present findings demonstrate that both ionic and nonionic contrast media increase the affinity of hemoglobin for oxygen and, therefore, that they may inhibit oxygen delivery to body tissues.

Angiography↗
PubMedDate not supplied

Effect of epidural and subarachnoid injections of a 10% butamben suspension.

Three groups of dogs were each given repeat epidural injections of a 10% butamben suspension. A fourth group received a single subarachnoid injection of the butamben suspension. All dogs were later sacrificed and the spinal cord, meninges and spinal nerves were examined. The dogs receiving the epidural injections had no pathology. Those dogs that received subarachnoid injections had adhesive arachnoiditis. None demonstrated any evidence of neurolysis. Two cancer patients who had each received multiple injections of a 10% butamben suspension for the successful treatment of cancer pain prior to their deaths had autopsies and the spinal cords, meninges and spinal nerves were examined. No significant pathology due to the butamben was noted. Epidural butamben does not appear to cause any local tissue damage provided that subarachnoid needle placement has been ruled out. Subarachnoid butamben should be avoided.

Anesthetics, Local↗