Thomas H. Joyce

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.

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 < 0.05). Calculated median percentage pain relief values for butorphanol were higher than morphine at each of these times (P < 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 < 0.01). The median time in the study was > 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.RésuméDans une étude à double insu lors de césarienne chez 92 parturientes à terme, nous avons comparé l’efficacité de 1, 2 et 4 mg de butorphanol à celle de 5 mg de morphine injectés dans le cathéter employé pour l’anesthésie épidurale à la lidocaïne. Nous jaugions la douleur postopératoire sur une échelle visuelle analogue et mesurions le pouls, la tension artérielle et la fréquence respiratoire. Les variables démographiques et la proportion de césariennes itératives étaient semblables dans les quatre groupes. Les valeurs médianes d’intensité douloureuse 15, 30, 45 et 60 min après l’injection de butorphanol étaient les mêmes pour les trois doses et étaient inférieures à celle de la morphine (P < 0,05); en même temps, les pourcentages médians de soulagement étaient plus grands avec le butorphanol qu’avec la morphine (P < 0,05). Toutefois, à 90 min et 2 h post injection, ces variables étaient les mêmes pour les deux morphiniques. A partir de la 45ième minute, de plus en plus de patientes traitées à la morphine ou au butorphanol nécessitaient d’autres analgésiques, mettant ainsi un terme à leur participation à l’étude mais à une fréquence différente selon le morphinique (P < 0,01). La durée médiane de participation à l’étude était de plus de 24 h pour la morphine et de 3, 2,5 et 4 h pour les doses de 1, 2 et 4 mg de butorphanol respectivement. Il n’y eut pas de modification clinique du pouls ou de la tension artérielle non plus que de bradypnée à moins de 12 min−1. Une seule des 69 patientes (1,4 pour cent) ayant reçu du butorphanol se plaint de prurit mais 10 des 23 patientes (43 pour cent) du groupe morphine firent de même. L’évaluation globale de l’efficacité analgésique était la même pour la morphine et le butorphanol. Le butorphanol épidural offre une analgésie postopératoire sûre et efficace; il agit rapidement et pendant une période limitée.

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.

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.

Bupivicaine-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 bupivicaine-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.RésuméĽanesthésie régionale est une technique convenable pour traiter une parturiente asthmatique. Nous rapportons le cas ďune asthmatique en travail chez qui ľadministration rapide ďune analgésie péridurale au bupivacaïne-fentanyl a été associée à une amélioration de ľefficacité ďune thérapie médicale concourante pour bronchospasme. Avant de débuter le blocage péridural, on a employé de ľatropine par inhalation dans une tentative de réduire le tonus parasympathique des muscles lisses bronchiques. Une amélioration clinique soutenue ne s’est produite qu’après la sortie du foetus et du placenta.

Uterine rupture associated with the use of vaginal Prostaglandin E2 suppositories

The authors present an obstetrical case of silent uterine rupture due to Prostaglandin E2 vaginal suppositories. Although this complication has been reported in the obstetrical literature, lack of attention to it in the anaesthesia literature, causes us to call this problem to the attention of anaesthetists.RésuméLes auteurs rapportent un cas de rupture utérine silencieuse attribuable à l’utilisation d’ovules vaginaux à la Prostaglandine E2. Cette complication est plus fréquemment rapportée dans les publications obstétricales que dans la littérature d’anesthésiologie. Aussi, les auteurs croient-ils important d’attirer l’attention des anesthé-sistes sur ce sujet.