Francis M. James

Phaeochromocytoma in Pregnancy. Caesarean Section under Epidural Analgesia

Two cases are reported in which Caesarean section was successfully performed under epidural analgesia in patients whose pregnancy was complicated by a phaeochromcytoma. Pre-operative phenoxybenzamine therapy together with careful peri-operative monitoring produced cardiovascular stability and led in both cases to the delivery of a healthy infant.

Oxyhemoglobin Saturation Following Cesarean Section in Patients Receiving Epidural Morphine, PCA, or IM Meperidine Analgesia

The frequency and severity of oxyhemoglobin desaturation was compared in 49 patients receiving epidural morphine, 5 mg (n = 21); patient-controlled analgesia (PCA) using meperidine (n = 20); or intramuscular (im) meperidine (n = 8) for postoperative analgesia following elective cesarean section performed with epidural anesthesia. Oxygen saturation (SpO2) was monitored for 24 h using a pulse oximeter; data were continuously collected and stored every 30 s via an interface connected to a computer. For analysis purposes, SpO2 was divided into five categories: 96-100%, 91-95%, 86-90%, 81-85%, and less than or equal to 80%. Although SpO2 remained above 95% for the majority of the monitored period, patients in all groups experienced periods of desaturation. PCA patients spent the longest cumulative time with SpO2 between 91 and 95%, 231 +/- 49 min (mean +/- SEM), compared with only 112 +/- 30 min and 152 +/- 42 min for the epidural and im groups, respectively (P less than 0.05 vs. epidural group). PCA patients also spent longest with SpO2 at 86-90% (19 +/- 10 min, vs. 6 +/- 3 and 0.5 +/- 0.3 min for the epidural and im groups, respectively), although this difference was not statistically significant. Severe desaturation episodes, defined as SpO2 less than or equal to 85% for more than 30 s, occurred in 71% of patients in the epidural group, 30% in the PCA group, and 63% in the im group (P less than 0.05 PCA vs. epidural and im).(ABSTRACT TRUNCATED AT 250 WORDS)

Verapamil Placental Transfer and Effects on Maternal and Fetal Hemodynamics and Atrioventricular Conduction in the Pregnant Ewe

Verapamil may have application in the field of obstetrics for treatment of maternal and fetal tachyarrhythmias. This study was performed to assess the maternal and fetal hemodynamic effects of this drug, as well as to determine its placental transfer and effects on maternal and fetal atrioventricular conduction in the pregnant ewe. Verapamil, 0.2 mg/kg, administered intravenously over 3 min, resulted in a transient decrease in maternal mean and diastolic blood pressures. There was, however, no significant change in fetal systolic, diastolic, and mean blood pressures. Maternal and fetal heart rates also were unchanged throughout the experiment. Atrioventricular conduction, assessed by measurement of PR intervals, was prolonged in both the ewe (41%) and the fetus (78%). Placental transfer of verapamil was limited, as shown by the umbilical vein to uterine artery drug concentration ratios of 0.35–0.45 throughout most of the experiment. Fetal hepatic extraction of the drug appeared to be substantial, since the drug concentration in the fetal carotid artery was less than that of the umbilical vein at 1, 3, and 5 min after drug injection.

A Controlled Trial of Extradural Fentanyl in Labour

In a double-blind trial carried out on patients in the first stage of labour, either fentanyl 80 micrograms (n = 35) or physiological saline (n = 33) was added to the test dose of bupivacaine and administered extradurally. Thereafter analgesia was maintained as necessary with 0.5% bupivacaine alone. Supplementary bupivacaine (a further dose within 1 h) was required to produce satisfactory analgesia in eight patients in the fentanyl group and in 26 patients in the control group. Analgesia was more rapid in onset and more complete in the fentanyl group, and the duration from first dose to first top-up was 2.36 h, compared with 1.66 h (supplements notwithstanding) in the control group. No serious side-effects were encountered in either group, although eight patients in the fentanyl group experienced mild itching, compared with one in the control group.

Smooth Muscle Effects of Lidocaine, Prilocaine, Bupivacaine and Etidocaine on the Human Umbilical Artery

The smooth muscle effects on human umbilical arteries of four different local anaesthetic agents - lidocaine, etidocaine, prilocaine and bupivacaine - were studied. Lidocaine and etidocaine relaxed the arteries, etidocaine more profoundly than lidocaine. Prilocaine in the concentration range 10-1,000 micrograms/ml caused pronounced contractions. Bupivacaine consistently evoked a contractile response in the concentration range 5-25 micrograms/ml, but at lower and higher concentrations the response to this drug was inconsistent. The concentrations of lidocaine were determined in six human umbilical arteries following maternal epidural block with this agent and were found to be 0.1 - 1.7 micrograms/g tissue. The contractile actions of prilocaine and bupivacaine on the human umbilical arteries are undesirable and might be hazardous if high concentrations are attained, e.g. during paracervical block.

Bearing Down at the Time of Delivery and the Incidence of Spinal Headache in Parturients

A major drawback to the use of spinal anesthesia for relief of pain during delivery is the associated high incidence of postlumbar puncture headache. Vandam and Dripps (1) reported an incidence of 22% in obstetric patients. It is generally believed that the spinal headache is secondary to leakage of cerebrospinal fluid (CSF) through the dural hole, which, resulting in reduced CSF volume and pressure, causes traction on the intracranial vessels and meninges. Some of the prophylactic measures advocated to reduce the incidence of spinal headache include prolonged bed rest, application of an abdominal binder, use of narrowgauge (2) or pencil-point spinal needles (3), lateral approach to the subarachnoid space (4, avoidance of spinal flexion on insertion of the needle (5), aggressive oral and parenteral fluid administration, longitudinal alignment of the spinal needle with the dural fibers, and prophylactic epidural injection of saline or autologous blood (6, 7). Some of the explanations given for the increased incidence of postlumbar puncture headace in parturients include: ( a ) relative dehydration, which could reduce the production of CSF; (b ) abrupt release of intra-abdominal pressure and venacaval compression upon delivery, which reduces epidural and epidural venous pressures; and ( c ) maternal bearing down efforts that could increase CSF leakage through the dural hole. Some clinicians advocate low outlet forceps delivery following institution of spinal anesthesia as a prophylactic measure to reduce the incidence of postpartum spinal headache. We initiated this prospective study to determine the influence of maternal bearing down efforts on the incidence of postlumbar puncture headache in parturients.

Allergic Reaction to an Amide Local Anaesthetic

A 67-yr-old female patient gave a history of allergy to lignocaine. When she was challenge-tested with the intradermal injection of 0.5% bupivacaine 0.2 ml she had a systemic reaction. This reaction was accompanied by a decrease in the concentration of complement C4 in the plasma, which indicated that the reaction was immunologically-mediated. This is the first report of allergy to a local anaesthetic drug which has been documented by concurrent immunological changes.