R. Jouppila

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.

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 maternal obesity on labour and labour pain

Consecutive obese (n = 53) and non‐obese parturients (n = 609) were prospectively evaluated during labour to analyse the influence of maternal obesity on labour pain and outcome. Excessive pre‐pregnancy weight was classified as a body mass index of 30 kg.m‐2 or more. Pain intensity was measured using an 11 point visual scoring scale. Obese parturients had more complicated pregnancies (hypertension and diabetes) and their babies weighed significantly more (3865g versus 3592 g, p<0.001). These differences did not affect labour pain experience, or the duration or mode of delivery. Eighty‐five percent of the obese parturients and 83% of the controls had high maximal pain scores during the first stage (> 7). Both groups received similar analgesia. More technical problems (p = 0.03) were experienced in establishing epidural analgesia for obese parturients, but this did not influence the success of pain treatment. After delivery, obese women were significantly more content with the pain relief received; only 12% vs 23% in the control group complained of poor pain control (p = 0.03). In this study, obesity and increased fetal size did not complicate labour or its outcome. Critical patient assessment should be emphasised, however, due to the physiological and medical problems present in obese parturients.

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.

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.

Segmental epidural analgesia in labour: related to the progress of labour, fetal malposition and instrumental delivery.

Abstract. The effect of low‐dose continuous segmental epidural analgesia given during the first stage of labour on the progress of labour, the frequency of fetal malpositions and the rate of vacuum extractions was studied prospectively in 100 parturients (epidural group). The results were compared with 100 parturients given none or conventional analgesia (control group). The results showed that in the primiparous epidural group the progress of labour before analgesia was induced was significantly slower than in the control group. After the block, however, the subsequent course of the labour was of equal duration in both groups. The durations of the second stages of labour did not differ significantly between the groups. The differences in fetal malpositions at delivery were statistically insignificant. Nor did the rate of vacuum extractions, 8% in the primiparous and 0% in the multiparous epidural group, differ statistically from the corresponding rate in the control groups. The results signify a normal progress and outcome of labour after low‐dose segmental epidural analgesia.

Effect of induction of general anesthesia for cesarean section on intervillous blood flow

Abstract. Intervillous blood flow was measured by a new intravenous 133Xe method before and during induction of general anesthesia for cesarean section in 10 healthy mothers. The flow values showed a highly significant decrease (p < 0.001) (35 per cent on an average) at the time of anesthesia compared with the control values. The impairment was observed in all the cases. The role of the maternal changes in hemodynamic parameters and acid‐base balance as a background of this decrease is discussed.

Ephedrine and phenylephrine for avoiding maternal hypotension due to spinal anaesthesia for caesarean section

The effects of i.v. vasopressors on Doppler velocimetry of the maternal uterine and placental arcuate arteries and the fetal umbilical, renal and middle cerebral arteries were studied during spinal anaesthesia in 19 healthy parturients undergoing elective caesarean section. Fetal myocardial function was investigated at the same time by M-mode echocardiography. The patients were randomized into two groups, to be given either ephedrine or phenylephrine as a prophylactic infusion supplemented with minor boluses if systolic arterial pressure decreased by more than 10 mmHg from the control value. Both the vasopressors restored maternal arterial pressure effectively. The ephedrine group showed no significant differences in any of the Doppler velocimetry recordings relative to the baseline values, but during the phenylephrine infusion the blood flow velocity waveform indices for the uterine and placental arcuate arteries increased significantly and vascular resistance decreased significantly in the fetal renal arteries. Healthy fetuses seem to tolerate these changes in uteroplacental circulation well, however, since the Apgar scores for the newborns and the acid-base values in the umbilical cord were within the normal range in both groups. The results suggest that some caution is required when selecting the specific vasopressor agent, the dosage and the mode of administration for the treatment of maternal hypotension secondary to spinal anaesthesia for caesarean section.

Does ephedrine influence newborn neurobehavioural responses and spectral EEG when used to prevent maternal hypotension during caesarean section

The recovery of 16 infants born by elective caesarean section with spinal anaesthesia, in which either ephedrine or fluid load was used to prevent maternal hypotension, were studied using Scanlons neurobehavioural tests and a computerized EEG. Neurobehavioural testing showed no differences between the ephedrine and the non‐ephedrine groups of infants at ages of 3 h, 1 day, 2 days and 4–5 days, whereas the spectral EEG showed significant differences between the two groups during the first 2 h after delivery, which had disappeared 24 h later. It is suggested that small doses of ephedrine given to the mother i.v. to prevent hypotension during spinal anaesthesia have short‐lived effects on the neonates central nervous system, which will be detected in the spectral EEG, but not in neurobehavioural tests.