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Biomedical subjects

F J Husain

Publications and source records attributed to F J Husain.

12 recordsLinked to original sources

A comparison of catheter vs needle injection of local anesthetic for induction of epidural anesthesia for cesarean section.

It is generally believed that bolus injections of local anesthetic through an epidural needle produce a more rapid onset of blockade, but at the expense of an increased incidence and severity of hypotension, whereas intermittent injections through a catheter take longer to achieve adequate anesthesia but with a lower risk of hypotension. The present study investigated two commonly used needle and catheter epidural injection techniques for differences in speed of onset of surgical anesthesia and incidence and severity of hypotension. Term parturients scheduled for elective cesarean section were randomized into two groups to receive epidural anesthesia with intermittent injection either through the epidural needle (n = 44) or via a previously placed catheter (n = 44). The incidence and severity of hypotension was similar in the two groups. No significant difference was found for the time to onset of surgical anesthesia. In the absence of benefits of needle injection, incremental catheter administration of local anesthetic with its multiple safety advantages is the technique of choice for induction of epidural anesthesia for cesarean section.

Clinical Trial↗

Incidence of venous air embolism during cesarean section is unchanged by the use of a 5 to 10 degree head-up tilt.

One hundred healthy parturients were divided at random into two demographically similar groups and were positioned for cesarean section either horizontally or flexed 5 to 10 degrees head up, with a 15 degrees lateral tilt. A Doppler ultrasound transducer was positioned over the fourth intercostal space parasternally. Initially, two patients received spinal, three general, and 95 epidural anesthesia. Two patients subsequently needed general for failed epidural anesthesia. Changes in Doppler heart tones (greater than 15 sec duration) indicative of venous air embolism (VAE) were identified 15 times in 11 patients--seven in supine and four in head-up patients (no statistically significant difference). Six awake patients (three horizontal, three head-up) developed chest tightness or pain during surgery, but only one episode correlated with VAE. No patient developed breathlessness. Moderate hypotension (greater than 10% decrease in systolic arterial pressure [SAP]) occurred in seven of 11 (63.6%) patients with, and in 26 (29.2%) of 89 patients without, VAE (P less than 0.001). More severe hypotension (SAP less than 90 mm Hg) due to bleeding occurred once. We conclude that a modest (5-10 degrees) head-up position does not influence the occurrence of VAE in patients having cesarean section. An 11% incidence of clinically insignificant VAE, although low, is still worrisome, as even small air bubbles in the circulation are potentially harmful, especially if the foramen ovale is patent. VAE during cesarean section should be anticipated and the anesthetic management planned accordingly.

Adult↗

Obesity, gravity, and spread of epidural anesthesia.

Epidural anesthesia was administered for cesarean section in 250 patients using 20 ml of 0.75% bupivacaine administered at L3-4 with the patient in a sitting position for 5 minutes. Comparing the results with those obtained in a previous study in which parturients were kept horizontal at all times, it was found that the sitting position limited cephalad spread of anesthesia only in obese patients and that the decrease in spread was in proportion to the degree of obesity. The previous findings that cephalad spread is positively correlated to body mass index BMI (weight in kilograms divided by height in meters squared) and with body weight were confirmed.

Anesthesia, Epidural↗

Brachial and femoral blood pressures during the prenatal period.

In 202 young primigravidas, right-sided brachial and femoral arterial pressures were recorded in both supine and left lateral positions during prenatal visits in the second and third trimesters. Roll-over tests were performed in 78 of these. Position-related falls predominantly in femoral artery pressure--indicative of aortic compression-were demonstrable earlier and with greater frequency than falls predominantly in brachial artery pressure-indicative of caval compression. While the sequelae of caval compression were perceived by the gravida, those of aortic compression were not. Therefore, education to the risks of the supine position should start early in pregnancy. There was no relationship between decreases in blood pressures and subsequent development of pre-eclampsia. Roll-over tests were positive in 45 gravidas (58%) and pre-eclampsia developed in 15 (33%). Roll-over tests were negative in 33 gravidas (42%) and pre-eclampsia developed in two (6%). This difference was significant at the 0.02 level.

Adolescent↗

Caesarean section associated with gross obesity.

The anaesthetic and surgical problems associated with Caesarean section in eight grossly obese patients (weight 150-204 kg) are described. In addition to an increase in the frequency and severity of the complications of obesity, those weighing more than 150 kg present a panniculus which may weigh 70 kg. Extradural analgesia was used for three patients and general anaesthesia for five (two because of fetal distress). One fetus died in utero after serious and prolonged arterial hypotension in the mother caused by powerful cephalad retraction of the panniculus (extradural analgesia). General anaesthesia was associated with severe episodes of hypertension in two patients.

Adult↗

Obesity and the cephalad spread of analgesia following epidural administration of bupivacaine for Cesarean section.

Epidural anesthesia using 20 ml of 0.75% bupivacaine at L3-4 with the patient in the left lateral position and the table horizontal was employed for cesarean section in 147 A.S.A. class 1 or 2 parturients under the age of 35 with a single fetus. The height of the analgesia was positively correlated with the body mass index (BMI) (weight in kilograms divided by the height in square meters), a measure of adiposity, and with body weight. Both correlations were statistically significant (p less than 0.001). There was no statistically significant correlation with the patients' height or age. It is concluded that higher levels of epidural block should be anticipated in obese obstetrical patients in proportion to their obesity. Twenty milliliters of 0.75% bupivacaine must frequently be augmented to provide adequate analgesia for cesarean section in thin parturients (BMI below 28) whereas it is too high a dosage for obese patients.

Adult↗

Double-blind comparison of maternal analgesia and neonatal neurobehaviour following intravenous butorphanol and meperidine.

Butorphanol (1 mg and 2 mg) and meperidine (40 mg and 80 mg), given intravenously, were evaluated for analgesic efficacy and safety in a double-blind randomized study employing 200 consenting pre-partum patients in moderate to severe pain during the late first stage of labour. Both drugs provided adequate relief of pain to the mothers. There was no significant difference in the rate of cervical dilation, the foetal heart rate, the Apgar score, pain relief or neonatal neurobehavioural scores betweeen those receiving butorphanol and those receiving meperidine. Twenty-two mothers who received butorphanol and eleven who received meperidine nursed their infants with no adverse effects observed. Side-effects were generally infrequent in this study; however, more side-effects were reported by the patients and observed by the investigator in the meperidine-treated cases (13%) than in the cases treated with butorphanol (2%).

Adult↗