A. Hollmén

Laryngeal Oedema as an Obstetric Anaesthesia Complication: Case Reports

Three cases of laryngeal oedema leading to endotracheal intubation dificulties in obstetric anaesthesia are described. The first case occurred immediately postpartum in a patient who developed a swollen face from strenuous bearing down efforts in the second stage of labour. The other two cases were patients with severe pre‐eclampsia including marked generalized oedema. The possibility of the occurrence of laryngeal oedema with resultant endotracheal intubation dificulties in obstetrics should be remembered when endotracheal intubation is considered to avoid the hazard of acid aspiration. The authors prefer the use of regional anaesthetic techniques (if not contraindicated) in obstetrics, and emphasize the use of prophylactic methods to minimize the risk of acid aspiration in connection with general anaesthesia, particularly where endotracheal intubation may be diflicult.

Transfer of clonidine and dexmedetomidine across the isolated perfused human placenta

Background: The placental transfer of the a2 receptor agonist clonidine, earlier used as an adjuvant in obstetric epidural analgesia, was compared with the transfer of the newer and more %‐selective agonist dexmedetomidine.

Visceral pain during caesarean section under spinal and epidural anaesthesia with bupivacaine.

In a randomized study, the incidence of visceral pain was evaluated in 46 patients undergoing elective caesarean section under spinal or epidural anaesthesia with 0.5% bupivacaine. If the patient experienced pain during the operation, a standard visual analogue scale ranging from 0 to 10 was used to assess the degree of pain Visceral pain occurred in 12/23 patients in the spinal group and in 13/23 patients in the epidural group. In neither group was a correlation found between the cephalad level of analgesia or the intensity of cutaneous analgesia in the sacral region, and the presence of visceral pain.

Neurologic activity of infants following anesthesia for cesarean section.

Elective cesarean section was performed in a consecutive scries of 30 patients with full-term pregnancies who were not in labor. Epidural (lidocaine, 1.5 per cent, with epincphrine, 1:200,000) and general anesthesia (thiopental, nitrous oxide-oxygen, succinylcholine infusion) was used alternately. Neonatal acid-base values and Apgar scores showed no significant difference between the two anesthetic groups, and most infants were vigorous at birth. The neurologic recoveries of the infants showed no significant difference between the two groups. In the group receiving epidural anesthesia, there was a significant correlation between maternal hypotension and weak rooting and sucking reflexes of the infants during the first two days. All infants of high-risk obstetric patients in the series, independent of anesthetic technique used, had abnormal neurologic activity, as evidenced by either depression of muscle tone and the reflexes or all the tested variables. Neurologic assessment as followed in this series is a sensitive indicator of the effects of fetal stress factors acting during cesarean section.

The effects of epidural ropivacaine and bupivacaine for cesarean section on uteroplacental and fetal circulation.

Background Ropivacaine is a new long-acting amide local anesthetic that has been shown in animal studies to have less dysrhythmogenic and cardiotoxic potential than bupivacaine. The intravenous administration of ropivacaine has not been associated with any detrimental effects on uterine blood flow in pregnant ewes. The purpose of this randomized, double-blind study was to examine the effects of epidural ropivacaine for cesarean section on blood flow velocity waveforms in uteroplacental and fetal arteries with color Doppler ultrasound and to assess whether the block modified fetal myocardial function.

The Effect of Segmental Epidural Analgesia on Maternal and Foetal Acid-base Balance, Lactate, Serum Potassium and Creatine Phosphokinase during Labour

Maternal and foetal acid‐base balance, Pao2, lactate, potassium and creatine phosphokinase (CPK) were studied during the course of 28 induced labours. Every second mother received segmental epidural analgesia during the first stage of labour (epidural group), while the remaining mothers (who were given pethidine for pain relief, if necessary) acted as a control group. In the epidural group the patients had only minimal changes in acid‐base balance and lactate concentration during the first stage. During the second stage lactate concentration increased. In the control group, on the other hand, the acid‐base balance showed signs of hyperventilation and lactic acid accumulation during the first stage. The potassium changes were quite minimal and were not significantly different between the groups. The CPK level did not change during labour, but 2 and 4 h after delivery it was significantly elevated in both groups. The foetal acid‐base balance, potassium, lactate and Pao2 values revealed no differences between the groups at any time. The CPK level in umbilical venous blood was significantly higher in the epidural group.

Axillary Plexus Block

In axillary plexus blocks employed in surgical procedures involving the upper extremity, comparisons were made between anaesthesias produced by 2% mepivacaine (Carbocaine®) with epinephrine 1:200,000 and 0.25 and 0.5% LAC‐43 (Marcaine®) with epinephrine 1:200,000, as to the effectiveness of the anaesthesia, duration of the anaesthesia, as well as the occurrence of post‐operative pain with each drug. The series of 59 blocks was divided according to the anaesthetics used into three comparable groups. The intensity of anaesthesia in various cutaneous and motor branches of the axillary plexus was used as the criterion for success of the blocks. This anatomical criterion was also compared with operability. As regards latency there are no statistically significant differences between the agents. Mepivacaine as 2% solution + epinephrine was found to be definitely more efficient than 0.5 or 0.25% LAC‐43 as regards the intensity of anaesthesia in various nerves. There were, however, no noteworthy differences in operability between mepivacaine and 0.5% LAC‐43, but 0.25% LAC‐43 proved to be unsatisfactory in this respect. The duration of both sensory and motor depression (anaesthesia) was prolonged more than twice with LAC‐43 (both 0.5 and 0.25%). The pain caused by operative trauma appeared after 12 hours with 0.5% LAC‐43 and after approx. 9 hours with 0.25% LAC‐43 and after about 3 1/2 hours with 2% mepivacaine. There were no noticeable side effects or neurological complications.

Parturients' assessment of water blocks, pethidine, nitrous oxide, paracervical and epidural blocks in labour

This prospective study evaluated the extent to which the analgesic procedures available resulted in efficient pain relief in 833 Finnish parturients. Their pain ratings were recorded according to their own assessment of pain intensity during labour before and after pain management and according to their total pain experience recalled on the third day after delivery. Only regional blocks significantly diminished pain scores during labour and a striking decrease in pain level (P < 0.0001) was maintained until the second stage by epidural analgesia (EDA) alone. The EDA-group consisted mainly of the primiparous (71%) with induced (17%) and most painful deliveries. After delivery 60% of parturients in this group recalled labour pain as being very severe or intolerable. This was partly due to delays in receiving epidural blockade and partly due to the parturients reticence in requesting analgesia. Pain relief was rated as excellent or good by 94% of the EDA group but by only 50% of the remaining patients.

Epinephrine Does Not Alter Human Intervillous Blood Flow during Epidural Anesthesia

: The effect of epinephrine given epidurally with local anesthetics on uterine blood flow is controversial. Previous work in pregnant ewes demonstrated a transient but significant (14 per cent) decrease in uterine blood flow when 2-chloroprocaine with epinephrine (10 micrograms/l) was used. The authors administered 2-chloroprocaine, 10 ml, with epinephrine (5 micrograms/ml) to 12 healthy women during the first stage of labor. By use of intravenously injected 133Xe, intervillous blood flow was measured before and 15-20 min after epidural anesthesia to a somatic level of at least T10. Intervillous blood flow did not change significantly despite a decrease in mean blood pressure of 11 torr. These conflicting results are probably best explained by methodologic and species differences. It is postulated that human placental vasculature, unlike that of the ewe, undergoes vasodilation when perfusion pressure is decreased to maintain placental blood flow.

Intervillous Blood Flow During Caesarean Section With Prophylactic Ephedrine and Epidural Anaesthesia

We administered a 15 mg i.v. bolus of ephedrine at the commencement of epidural blockade to nine healthy parturients scheduled for elective caesarean section. Nine other patients did not receive prophylactic ephedrine before epidural anaesthesia (control group). Lactated Ringer solution, 30 ml/kg, was infused before and during blockade, and left uterine displacement was used to minimize aortocaval compression. A133Xe i.v. technique was used to measure intervillous blood flow (IBF) before and 20–25 min after epidural block. The mean arterial pressure (MAP) decreased after epidural blockade in the ephedrine group by 0.67 ± 0.8 (mean ± s.d.) kPa and by 1.20 ± 1.1 (mean ± s.d.) kPa in the control group. In spite of the decrease in MAP, IBF increased by 6% in patients receiving ephedrine (N.S.), whereas it decreased by 11% in the control group (N.S.). In the ephedrine group there was in this preliminary study a trend to increasing IBF during falling perfusion pressure (MAP). The results of this preliminary study suggest that ephedrine will not affect IBF, but to prevent maternal hypotension ephedrine should be used as an i.v. infusion instead of a bolus injection.