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Biomedical subjects

T H Joyce

Publications and source records attributed to T H Joyce.

At least 19 recordsLinked to original sources
PubMed1991

Post-caesarean section analgesia: a comparison of epidural butorphanol and morphine.

Epidural butorphanol 1, 2 and 4 mg were compared with morphine, 5 mg, for postoperative analgesia in 92 consenting, healthy, term parturients who had undergone Caesarean section under epidural lidocaine anaesthesia in a randomized double-blind study. Postoperative pain was assessed using a visual analogue scale and recorded with heart rate, blood pressure and respiratory rate. The demographic characteristics, and the incidences of primary and repeat Caesarean sections, were not different among the four treatment groups. At 15, 30, 45 and 60 min after treatment the median pain scores following butorphanol were similar and lower than those following morphine (P less than 0.05). Calculated median percentage pain relief values for butorphanol were higher than morphine at each of these times (P less than 0.05). At 90 min and 2 hr the pain scores and pain relief values were similar. Beyond 45 min the number of patients requesting supplemental medication and dropping out of the study increased progressively in both the butorphanol and morphine treated patients. The attrition profiles for butorphanol were different from morphine (P less than 0.01). The median time in the study was greater than 24 hr for morphine, and 3, 2.5 and 4 hr for butorphanol, 1, 2 or 4 mg, respectively. No patient developed a clinically important change in heart rate or blood pressure, and none experienced a decrease in respiratory rate below 12 breaths.min-1. One of 69 patients (1.4 per cent) who received butorphanol developed pruritus compared with ten (43 per cent) of 23 patients who received morphine. The global assessments of the adequacy of analgesia were indistinguishable between morphine and butorphanol. Epidural butorphanol provides safe, effective postoperative analgesia, has a prompt onset, and a limited duration.

Adult↗
PubMed1991

The hemodynamic effects of intubation during nitroglycerin infusion in severe preeclampsia.

The effectiveness of intravenous nitroglycerin infusion in lowering maternal blood pressure and in blunting the hemodynamic responses to endotracheal intubation was evaluated in six primigravid women with severe preeclampsia. Monitoring consisted of continuous electrocardiogram monitoring, arterial cannulation, and flow-directed pulmonary arterial catheterization in each patient. All patients underwent oxytocin induction of labor and crystalloid and/or colloid expansion to produce a pulmonary capillary wedge pressure of 10 to 15 mm Hg and a colloid osmotic pressure of greater than 17 mm Hg. Intravenous nitroglycerin was administered before induction of general anesthesia. The hemodynamic effects associated with endotracheal intubation revealed a change in the heart rate from 104 +/- 10 to 133 +/- 17 beats/min, an increase in mean arterial pressure from 134 +/- 12 to 164 +/- 32 mm Hg, and an increase in systemic vascular resistance from 1262 +/- 342 to 1351 +/- 259 dynes-sec-cm-5 that was accompanied by a small change in the cardiac index from 4.5 +/- 1.2 to 4.5 +/- 0.9 L.min-1.m-2.

Acute Disease↗
PubMed1990

Vecuronium for rapid-sequence intubation for cesarean section.

Because succinylcholine may occasionally be contraindicated for rapid-sequence induction in parturients, we studied the use of vecuronium in 21 patients having elective cesarean sections. Eleven patients (group 1) received 10 micrograms/kg vecuronium as a priming dose, followed 4-6 min later by 100 micrograms/kg. Ten patients (group 2) received 200 micrograms/kg vecuronium as a bolus. Onset, the time from the injection of vecuronium to maximal twitch suppression, and clinical duration, the time between vecuronium administration and return to 25% of the control twitch height, were recorded. Umbilical and maternal venous blood samples at delivery were analyzed for vecuronium concentrations. One-minute and 5-min Apgar scores and 1- and 24-h Neurologic and Adaptive Capacity Scores (NACS) were recorded. Individual tests of passive and active tone within the overall NACS profile were compared to evaluate further any residual vecuronium effects in the infants. Onset of neuromuscular blockade was 177 s in group 1 and 175 s in group 2. The corresponding clinical durations were 73 and 115 min. Maternal and umbilical venous vecuronium concentrations were 515 and 73 ng/mL in group 1 and 838 and 107 ng/mL in group 2. Seventy percent of neonates in group 1 had Apgar scores greater than 7 at 1 min, with 100% greater than 7 at 5 min. Corresponding values in group 2 infants were 50% and 80%. Fifty percent of group 1 infants had NACS of 35-40 at 1 h, and 70% at 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The effect of H2-receptor antagonist premedication on the duration of vecuronium-induced neuromuscular blockade in postpartum patients.

The clinical duration of vecuronium was measured in two groups of postpartum patients undergoing elective tubal ligation. Ten patients received no premedication and ten others ranitidine 150 mg orally the morning of surgery. The mean duration of action of vecuronium was 57.2 +/- 9.9 min in the unmedicated patients and 54.0 +/- 12.9 min in the ranitidine treated patients. These values were significantly greater than the mean value for nonpregnant control patients (35.3 +/- 8.4 min) but indistinguishable from the mean value for cimetidine pretreated patients (63.0 +/- 17.6 min) reported previously. The combined results of the previous and present studies provide convincing evidence that the clinical duration of vecuronium-induced neuromuscular blockade is significantly longer in the postpartum patient and independent of cimetidine or ranitidine pretreatment.

Female↗
PubMed1987

Prophylaxis for pulmonary acid aspiration.

Pulmonary acid aspiration in the perioperative period was first noted as a medical concern more than 40 years ago. Despite this awareness, identification of the patient at risk is by no means certain, and the true incidence of this condition is not known. Various therapeutic interventions have been proposed and tried. Physical therapies, such as pressure on the cricoid, have been successful, as has the administration of clear antacids prior to surgery. The histamine (H2)-receptor antagonists cimetidine and ranitidine have also been used successfully as prophylactic therapy when enough time is available prior to operation to make preoperative dosing practical. Metoclopramide, which can be given intravenously, may be useful in emergency surgery. When the degree of risk is high, concurrent use of physical and pharmaceutical interventions is recommended.

Histamine H2 Antagonists↗
PubMed1987

Determination of hydralazine in human plasma by high-performance liquid chromatography with electrochemical detection.

Hydralazine is used as an antihypertensive vasodilator drug. A specific and sensitive method for extraction and analysis of hydralazine by high-performance liquid chromatography (HPLC) with electrochemical detection was developed. Hydralazine and 4-methylhydralazine (internal standard) in plasma were derivatized at room temperature with salicylaldehyde. The derivatives were extracted in basic medium with a mixture of heptane, methylene chloride and isopentyl alcohol. A very good separation of hydralazine and 4-methylhydralazine from matrix material was achieved on a Supelcosil LC-18-DB (5 microns) reversed-phase column kept at 28 degrees C with a mobile phase of 66% methanol in 0.055 M citric acid/0.02 M dibasic sodium phosphate (pH 2.5). The hydralazine level was measured electrochemically by a screen oxidation mode. This method offers significant advantages in sensitivity, specificity and accuracy. Sample analysis by HPLC required less than 8 min. Application of the method to monitor plasma levels of hydralazine from a patient receiving the drug for the treatment of severe pregnancy-induced hypertension is discussed.

Chromatography, High Pressure Liquid↗
PubMed1987

Bupivacaine-fentanyl epidural analgesia for a parturient in status asthmaticus.

Regional anaesthesia is a suitable technique for the management of the asthmatic parturient. We report the case of an asthmatic gravida in labour in whom prompt institution of bupivacaine-fentanyl epidural analgesia was associated with enhancement of the effectiveness of concurrent medical therapy for bronchospasm. Prior to the initiation of epidural blockade, inhaled atropine was employed in an effort to reduce parasympathetic tone in the bronchial smooth muscle. Sustained clinical improvement did not occur until after delivery of the fetus and placenta.

Adult↗
PubMed1986

Role of intravenous nitroglycerin in the treatment of severe pregnancy-induced hypertension complicated by pulmonary edema.

Intravenous nitroglycerin would appear to be an ideal agent for the treatment of severe pregnancy-induced hypertension complicated by cardiogenic pulmonary edema. Nitroglycerin infusion effectively reduces preload by venous dilatation and, at higher doses, results in arterial vasodilatation. Because of these pharmacologic properties, the effects of intravenous nitroglycerin were studied in three patients with severe pregnancy-induced hypertension complicated by pulmonary edema. The major cardiovascular effects of nitroglycerin were to reduce the mean pulmonary capillary wedge pressure from 27 +/- 4 to 14 +/- 6 mm Hg, which result in a change in the colloid osmotic pressure to pulmonary capillary wedge pressure gradient from -10 to 2 mm Hg. No significant changes occurred in heart rate, central venous pressure, or cardiac index. Analysis of oxygen-related parameters revealed a significant (p less than 0.05) increase in oxygen delivery and extraction accompanied by a 53% increase in oxygen consumption. The changes in oxygen-related variables appeared to be secondary to a fall in mixed venous oxygen tension from 39 +/- 4 to 33 +/- 1 torr. These changes occurred without any significant improvement in arterial oxygen tension. We conclude that while intravenous nitroglycerin expeditiously corrects the hydrostatic derangements of pulmonary edema seen in pregnancy-induced hypertension, a rapid improvement in arterial oxygenation does not occur.

Female↗
PubMed1986

Cardiovascular alterations in severe pregnancy-induced hypertension: effects of intravenous nitroglycerin coupled with blood volume expansion.

Control of blood pressure in severe pregnancy-induced hypertension has often relied on agents with an unpredictable onset and duration of action. Because intravenous nitroglycerin is a potent, rapidly acting agent with a hemodynamic half-life measured in minutes, we evaluated its cardiovascular effects with and without volume expansion in six patients with severe pregnancy-induced hypertension. Nitroglycerin alone reduced mean arterial pressure by 27.5% without any significant changes in heart rate, central venous pressure, or stroke volume. The pulmonary capillary wedge pressure fell from 9 +/- 3 to 4 +/- 2 mm Hg (p less than 0.05) while the cardiac index decreased from 3.51 +/- 0.67 to 2.87 +/- 0.76 L/min X m2. Oxygen delivery fell significantly (p less than 0.05), from 617 +/- 78 to 491 +/- 106 ml/min X m2. While volume expansion alone had no effect on mean arterial pressure, the combination of blood volume expansion and nitroglycerin resulted in a marked resistance to the hypotensive effect of nitroglycerin. Cardiac index, pulmonary capillary wedge pressure, and oxygen utilization were not significantly different from baseline values when volume expansion preceded nitroglycerin. We conclude that the ease with which nitroglycerin reduces blood pressure is dependent on the individual patient's volume status. Although volume expansion allows one to maintain cardiac index, pulmonary capillary wedge pressure, and oxygen utilization when used in combination with nitroglycerin, this benefit may be offset by a concomitant reduction in hypotensive capability.

Adolescent↗
PubMed1986

Maternal cortical vein thrombosis and the obstetric anesthesiologist.

Maternal cortical vein thrombosis is a potentially fatal complication of pregnancy and the puerperium. Patients may present with focal neurologic deficits, seizures, or symptoms indicating increased intracranial pressure. Associated conditions include maternal dehydration and preeclampsia or frank eclampsia. Parturients may require anesthesia for various types of delivery. Safe administration of appropriate anesthesia must take into account the possible presence of a coagulopathy or reduced intracranial compliance. Case presentations, a literature review, possible pathogenetic mechanisms, and specific anesthetic considerations are discussed to enable the obstetric anesthesiologist to develop a rational plan of management.

Adolescent↗
PubMed1986

Influence of crystalloid versus colloid infusion on peripartum colloid osmotic pressure changes.

Plasma colloid osmotic pressure acts to retain fluid in the intravascular space. Intravenous crystalloids have been identified as one of the major factors contributing to the consistent peripartum decline in colloid osmotic pressure. This study was undertaken to compare the effect of two crystalloid infusions (1000 and 2000 mL Plasma-Lyte A) and a colloid infusion (1000 mL 5% albumin) on the peripartum colloid osmotic pressure. Before elective cesarean section, 45 parturients received one of the three infusions. The lowest mean maternal colloid osmotic pressure (16.6 +/- 1.1 mmHg, P less than .05 compared with baseline) occurred in the 2000-mL crystalloid infusion group eight to 16 hours postpartum. Although the colloid osmotic pressure fell in all groups postpartum, this reduction was significantly (P less than .05) less during the first 24 hours in the colloid infusion group. Minimizing this disruption of the colloid osmotic pressure to pulmonary capillary wedge pressure gradient may be clinically important in selected patients.

Cesarean Section↗
PubMed1985

Prehospital endotracheal intubation: rationale for training emergency medical personnel.

Endotracheal intubation by emergency medical services (EMS) personnel in the prehospital setting decreases morbidity and helps to improve the outcome of critically ill patients, especially those with cardiac or respiratory arrest, multiple injuries, or severe head trauma. The endotracheal tube facilitates better oxygenation and ventilation because it enhances lung inflation and protects the lungs from aspiration. No other alternative modality is as efficacious. Compared to physicians in general, properly instructed, well-supervised paramedics can be trained to perform this procedure safely and more efficiently in the emergency setting. The use of the endotracheal tube in the prehospital setting should be strongly encouraged and the training of EMS personnel in this skill should be given high priority.

Allied Health Personnel↗
PubMed1977

Clinical pharmacokinetics of lorazepam. II. Intramuscular injection.

A single dose of 4 mg of lorazepam was injected into the deltoid muscles of six healthy male volunteers. Multiple venous blood samples were drawn during 48 hr after the dose and all urine was collected for 24 hr after the dose. Concentrations of lorazepam and its major metabolite, lorazepam glucuronide, were determined by electron-capture gas-liquid chromatography. Lorazepam was rapidly absorbed from the injection site, reaching peak concentrations within 3 hr. Mean pharmacokinetic pamrameters for unchanged lorazepam were: apparent absorption half-life: 21.2 min; elimination half-life: 13.6 hr; volume of distribution: 0.9 L/kg; total clearance: 58.2 ml/min. Lorazepam glucuronide rapidly appeared in plasma, reached peak concentrations within 12 hr of the dose, then was eliminated approximately in parallel with the parent drug. Within 24 hr a mean of 47.6% of the dose was recovered in the urine as lorazepam glucuronide and less than 0.5% was recovered as unchanged lorazepam.

Adult↗