Neonatal neurobehavioral tests following cesarean section under general and spinal anesthesia

Effects of different anesthetic techniques on neurologic and adaptation capacity in newborn with elective cesarean section

Background:

Neurologic and Adaptive Capacity Scoring (NACS) has been introduced as a screening test for diagnosis of central nervous system depression due to intrapartum drugs on the neonate. This test can show neurological and behavioral changes even in the presence of a normal Apgar score. NACS has 20 indicators, each indicator allocating to itself the score zero, one or two. The aim of this study was to compare the effects of different anesthetic techniques on the NACS values.

Materials and Methods:

This study was performed as a randomized, single-blind clinical trial on 75 infants born with elective cesarean in Shahid Beheshti Hospital, Isfahan. Simple Sampling method was carried out and the information was gathered by questionnaires. Anesthetic techniques included general, spinal or epidural anesthesia. NACS score was assessed at 15^th min, 2 and 24 h after birth and then the anesthesia technique was recorded in the questionnaire. NACS score 35 or above was considered normal and 34 or less was abnormal.

Results:

In the present study, no significant correlation was found between the anesthesia techniques and NACS score. The mean NACS at 15 min after birthin the general, spinal and epidural groups were 33.5 ± 2.2, 33.0 ± 4.4 and 33.7 ± 1.6 respectively (P = 0.703).

Conclusion:

All three anesthetic techniques have identical effects on neurological and compatibility capacity of neonates born with elective cesarean; so, this could necessarily be a base to recommend the three methods equally.

Naloxone during neonatal resuscitation: acknowledging the unknown

There are no studies to support or to refute the current recommendations regarding naloxone concentration, routes for administration, and doses in neonatal resuscitation in the delivery room. Given the lack of supporting evidence, naloxone should not be given routinely in the delivery room to depressed neonates whether or not they are exposed to opioids before delivery because no important improvement has been documented and the drug may have potential short- and long-term harmful effects.

Is ephedrine infusion more effective at preventing hypotension than traditional prehydration during spinal anaesthesia for caesarean section in African parturients?

BACKGROUND

Hypotension following spinal anaesthesia for caesarean section may result in maternal nausea and vomiting and decreased uteroplacental blood flow with possible fetal acidaemia. Numerous methods have been tried to minimise hypotension. In developing countries where resources are limited, this study aimed to compare a standard infusion of ephedrine with traditional prehydration to prevent spinal hypotension.

METHOD

Sixty patients for elective caesarean section were randomly allocated to group 1: 1 L 0.9% saline before spinal block, and group 2: infusion of ephedrine 30 mg in 1 L of 0.9% saline after spinal block, titrated to maternal systolic pressure. Spinal anaesthesia was achieved with 2.5 mL of 0.5% heavy bupivacaine in the L3/L4 interspace.

RESULTS

Systolic pressure decreased 5 min after spinal block. Group 2 had higher mean values of systolic pressure throughout most of the study period than group 1 (P < 0.05). Hypotension occurred in 70% of patients in group 1 and 40% of patients in group 2 (P = 0.037). Severe hypotension occurred in 40% of group 1 and 13.3% of group 2 (P = 0.039). Nausea was the most common side effect of hypotension, occurring in 39.4% of all hypotensive patients. Other complications, including hypertension, tachycardia and bradycardia were similar in the two groups. Neonatal outcome was similar in the two groups and median Apgar scores at one and five minutes were 8.

CONCLUSION

Prophylactic ephedrine given by standard infusion set was more effective than crystalloid prehydration in the prevention of hypotension during spinal anaesthesia for elective caesarean section.

Sedation and analgesia for gastrointestinal endoscopy during pregnancy

Endoscopy during pregnancy raises the unique issue of fetal safety. Endoscopic medications comprise a significant component of fetal risks from endoscopy. Before endoscopy, the gastroenterologist or anesthesiologist should evaluate the potential fetal risks of sedation and analgesia, identify any contraindications to endoscopy, stabilize the maternal medical status as necessary, and correct maternal hypoxia or hypotension. The mother should be informed about the potential teratogenic risks of endoscopic medications during pregnancy. Patients who receive sedation and analgesia should be monitored during endoscopy by continuous electrocardiography, continuous pulse oximetry, and intermittent sphygmomanometry, as well as by the pulse and respiratory rate. General principles of sedation and analgesia during pregnancy include use of the minimal effective dose, avoidance of unnecessary medications, and preferable use of Food and Drug Administration category B medications.

Neurofunctional deficits and potentiated apoptosis by neonatal NMDA antagonist administration

The early postnatal brain development, when many potentially sensitive processes occur, has been shown to be vulnerable to different pharmacological and environmental compounds. In the present investigation, four groups of neonatal NMRI male mice were administered the glutamate NMDA receptor antagonist ketamine (50 mg/kg, s.c.), or the GABA(A) receptor agonist diazepam (5 mg/kg, s.c.), or co-administered ketamine (50 mg/kg, s.c.) and diazepam (5 mg/kg, s.c.), or vehicle (0.9% saline, s.c.) on day 10 after birth. On day 11, mice from each treatment group were sacrificed and brains were taken for analysis of neuronal cell degeneration, using Fluoro-Jade staining technique. Ketamine, but not diazepam, induced a severe degeneration of cells in the parietal cortex. The opposite was observed for diazepam in the laterodorsal thalamus. The most pronounced cell degeneration was seen in parietal cortex of mice exposed to both ketamine and diazepam. At 2 months of age each treatment group was tested for motor activity and learning performance. Ketamine and ketamine + diazepam treated mice displayed severe deficits of habituation to the test chamber in the spontaneous motor activity test, marked deficits of acquisition learning and retention memory in the radial arm maze-learning task and less shift learning in the circular swim maze-learning task. This study indicates that the observed functional deficits can be related to cell degeneration induced during a critical stage of neonatal brain development. The potentiated apoptosis induced by ketamine and diazepam may have implications for the selection of drugs used in neonatal paediatric anaesthesia.

Spinal anaesthesia for obstetrics

For a long time, epidural anaesthesia has been considered the method of choice for Caesarean delivery. The increased incidence of hypotension by the rapid onset of sympathetic blockade under spinal anaesthesia has been associated with a decline in uteroplacental blood flow and significant fetal acidosis, which may compromise neonatal well-being. Nevertheless, a decrease in fetal pH has not been shown to reduce neonatal Apgar or neurobehavioural assessment scores. Maternal blood pressure can be preserved with little side effects with low doses of vasopressors. On the other hand, spinal anaesthesia conveys significant advantages over epidural anaesthesia such as the simplicity of its use and the speed of onset, which allows neuraxial anaesthesia in urgent Caesarean sections and thus reduces the necessity for general anaesthesia. The small doses of local anaesthetics required to perform spinal anaesthesia reduce the risks of systemic toxicity to zero. Spinal anaesthesia is now considered the method of choice for urgent Caesarean section. The use of intrathecal opioids has profoundly changed the quality of spinal anaesthesia, with improved analgesia, a reduction in local anaesthetic requirements and shorter duration of motor blockade. Preliminary studies indicate that spinal anaesthesia may be safely performed in patients with severe pre-eclampsia, in whom spinal anaesthesia was previously considered contraindicated.

Hyperactivity following postnatal NMDA antagonist treatment: reversal by D-amphetamine

Three experiments were performed to study the effects of neonatal administration of glutamate receptor antagonists, on either Day 11 (dizocilpine = MK-801, 3 x 0.5 mg/kg, s.c., injected at 0800, 1600 and 2400 h) or Day 10 (Ketamine, 1 x 50 mg/kg, s.c., or Ethanol-Low, 1 x 2.5 mg/kg, or, Ethanol-High, 2 x 2.5 mg/kg, s.c., with 2-h interval) to male mice pups, on spontaneous motor behavior, habituation to a novel situation and D-amphetamine-induced activity in the adult animals. Mice administered MK-801 showed initial hypoactivity followed by hyperactivity over the later (20-40 and 40-60 min) periods of testing. Mice administered Ketamine and Ethanol-High similarly displayed an initial hypoactivity followed by hyperactivity over the later time (20-60 min) of testing. Habituation to the novel activity test chambers was reduced drastically in the MK-801 mice compared with vehicle-treated mice. Similarly, mice administered Ketamine and Ethanol-High displayed too drastically reduced habituation behavior. The low dose of D-amphetamine (0.25 mg/kg) reduced the hyperactivity of neonatal MK-801-treated mice, particularly from 30-60 min onwards, and elevated the activity level of the vehicle-treated mice. Similarly, the low dose of D-amphetamine (0.25 mg/kg) reduced the hyperactivity of neonatally Ketamine-treated and Ethanol-High-treated mice, particularly from 30-60 min onwards, and elevated the activity level of the respective vehicle-treated mice. Fluoro-jade staining per mm(2) regional brain tissue of MK-801 mice pups expressed as percent of vehicle mice pups showed also that the extensiveness of staining was markedly greater in the parietal cortex, hippocampus, frontal cortex, and lesser so in the laterodorsal thalamus. Ketamine-treated mice showed cell degeneration mainly in the parietal cortex, whereas the Ethanol-High mice showed marked cell degeneration in both the parietal and laterodorsal cortex. The present findings that encompass a pattern of regional neuronal degeneration, disruptions of spontaneous motor activity, habituation deficits and reversal of hyperactivity by a low dose of D-amphetamine suggest a model of Attention Deficit Hyperactivity Disorder that underlines the intimate role of N-methyl-D-aspartate (NMDA) receptors in the developing brain.

Electrophysiological responses from a temporal order continuum in the newborn infant

Auditory Evoked Responses (AERs) were used to investigate discrimination of temporal order differences in eight male and eight female newborn infants. The temporal lags in two-tone non-speech stimuli-known as tone-onset time (TOT)-modeled the temporal delay of voicing-onset time (VOT), an important cue for voicing contrasts. Analyses on peak amplitude measures and principal component scores indicated that the amplitude of the second negative AER deflection (N530) recorded from the left and right parietal leads changed abruptly as TOT values increased from +20 to +40 msec. However, no differences were noted between tokens that belonged in the same adult perceptual categories. A similar pattern of variability was observed for the amplitude of the first major negative peak (N200). Our findings indicate that the neurophysiological mechanisms underlying categorical-like distinctions of a temporal voicing cue used in speech perception may have an innate basis. Since both hemispheres produced similar responses at birth, the present data suggest that brain mechanisms involved in temporal order processing undergo significant reorganization during the first years of life.

Spinal anaesthesia in obstetrics

Spinal anaesthesia has been used since the 1800s but, due to a number of complications, the popularity of this technique has waxed and waned. In the 1950s, it was the most widely used method of anaesthesia and analgesia in obstetrics but it fell out of fashion with the arrival of the epidural technique which allowed a continuous method of delivering analgesia with relatively few complications. Hypotension and the high incidence of postdural puncture headaches were two reasons for the decline in the popularity of spinal anaesthesia in the young, otherwise healthy pregnant population. With the development of newer needles and bevel designs and methods whereby the incidence of hypotension can be minimized, spinal anaesthesia is making a reappearance in obstetrical anaesthesia spheres. The purpose of this article is to review the history, effects, technique, indications, contraindications and complications of this method of anesthesia as it applies to the obstetrical patient.

Use of sevoflurane during elective cesarean birth: a comparison with isoflurane and spinal anesthesia

This randomized study compared sevoflurane 1% and isoflurane 0.5% in terms of maternal and neonatal outcomes. In addition, neonatal outcome in both groups was compared with a cohort of patients delivered by cesarean birth using spinal anesthesia. Fifty-five patients presenting for elective cesarean birth under general anesthesia were randomly assigned to receive either sevoflurane 1% or isoflurane 0.5% in a 50% nitrous oxide and oxygen mixture for maintenance. Twenty patients requesting regional anesthesia received a subarachnoid block using 1.5 mL bupivacaine 0.75% in 8.25% dextrose with fentanyl 10 micrograms. Intraoperative hemodynamic variables and perioperative adverse events were recorded. Neonatal data included Apgar scores at 1 and 5 min, umbilical artery gas analysis, neurologic adaptive capacity scores (NACS) at 2 and 24 h, and a modified neonatal behavioral assessment scale (NBAS) at 24 h. Sevoflurane and isoflurane at equianesthetic concentrations (0.46 MAC-h [minimum alveolar anesthetic concentration hours]) were associated with similar blood pressure and heart rate changes during the operation. Blood loss, uterine tone, and perioperative complications were not problematic and were similar with the two drugs. No differences were seen in emergence times or in the time to being judged fit for discharge from the recovery room. Similarly, the level of postoperative comfort was the same in both groups. Comparing the general and the spinal anesthetic groups, no differences could be detected in neonatal outcome. Fluoride concentrations were modestly increased above preoperative levels in maternal and umbilical blood samples after sevoflurane administration.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of spinal and general anaesthesia for elective caesarean section: effect on neonatal condition at birth

The condition of 74 neonates delivered by elective caesarean section under general anaesthesia was compared with that of 63 neonates delivered under spinal anaesthesia. When the uterine incision - delivery interval was less than 3 min, neonates in the spinal group exhibited a higher Apgar score at 1 min (P < 0.002) and a higher mean umbilical venous pH (P < 0.05) than the equivalent general anaesthesia group; a significantly greater proportion of the neonates delivered under general anaesthesia had an umbilical venous pH<7.28 at delivery (P < 0.05), a fact which previous work suggests is important. Among anaesthetized mothers inspired oxygen concentration (33% or 50%) before delivery had no significant effect upon neonatal outcome. It is concluded that neonates delivered at elective Caesarean section under spinal anaesthesia are in better condition than those delivered under general anaesthesia.

Neurological adaptation of infants delivered by emergency or elective cesarean section

The effects of intrapartal asphyxia on neonatal neurological condition have been studied in 17 full-term infants delivered by emergency cesarean section and in 30 full-term infants delivered by elective cesarean section used as controls. A neurological examination consisting of 31 items was performed on days 1, 2 and 5 after birth. A tonus score, an excitability score as well as the number of optimal responses were calculated. A follow-up examination was done at six months of age with a standardized neurological and developmental examination. The results showed that infants born after emergency cesarean section were significantly more hypotone the first two days after delivery than the infants in the elective cesarean section group. In regard to individual neurological items, significant differences were found between the emergency and elective cesarean section in reaction to sound, rooting, patellar, Moro and stepping reflexes with weaker reactions in the elective cesarean section group. Growth, psychomotor development and neurological status at six months did not differ significantly between the groups. Our findings indicate that full-term infants born after emergency cesarean section due to mild intrapartal asphyxia have a delayed neurological adaptation as expressed by poor muscular tonus during their first days of life compared with infants born after elective cesarean section.

Cardiac output measurements for guidance of perioperative intravenous hydration in an obstetric patient

The administration of regional anesthesia to women with moderately severe and severe pre-eclampsia is commonly preceded by intravenous hydration guided by central venous pressure (CVP) monitoring. We are reporting the case of a gravida with incipient HELLP syndrome whose fluid management before, during, and after cesarean section under continuous extradural block was guided by non-invasive cardiac output measurements.

Haemodynamic effects of ketamine and thiopentone during anaesthetic induction for caesarean section

Ketamine (1 mg . kg-1) or thiopentone (4 mg . kg-1) was used to induce anaesthesia for Caesarean section in 62 normotensive patients. During induction of anaesthesia and before laryngoscopy, blood pressure did not change in either group (preinduction systolic blood pressure, 131 mmHg, and diastolic blood pressure, 75 mmHg). When laryngoscopy and intubation were performed, mean blood pressures of both patient groups increased 20-30 per cent. With ketamine (n = 30) heart rate was unchanged from the preinduction rate of 85 beats/min before laryngoscopy and increased significantly by 15 per cent during laryngoscopy and intubation. With thiopentone (n = 32), heart rate increased significantly to 20 per cent above the preinduction rate of 87 beats/min during induction and increased further (to 35 per cent above the preinduction rate) during laryngoscopy and intubation. The average maximal rate-pressure product calculated for the thiopentone group was over 18,000, which was significantly higher than the 15,000 calculated for the ketamine group. Neonatal outcome as assessed by Apgar score and umbilical blood gas analysis was good and did not differ significantly between groups.

Ketamine as induction agent for caesarean section

A series of 100 patients undergoing caesarean section was studied using ketamine 1.2 mg/kg as induction agent. Fifteen minutes prior to induction, atropine 0.25-0.5 mg and diazepam 1 mg was given intravenously as premedication. Anaesthesia was maintained with N2O:O2, FIO2 0.4. Once the umbilical cord was clamped, 0.2 mg fentanyl and 9 mg diazepam was given intravenously. Except for nitrous oxide, no more anaesthetic intravenous or inhalational agent was needed. Despite the fact that patients with known intrauterine asphyxia before the induction were included in the material, we found excellent Apgar scores (mean 9.1 at 1 min and 9.9 at 5 min). None of the patients reported awareness during the operation. Eight patients experienced pleasant dreams and three unpleasant. There were no hallucinations in the recovery area. The mental condition of the mothers after the operation was acceptable. It is suggested that ketamine can be used not only on special indications but also as a routine method for induction of anaesthesia for caesarean section.

Comparison of thiopentone and methohexitone as induction agents for Caesarean section

Anaesthesia was induced with equipotent doses of either thiopentone or methohexitone in 127 women undergoing Caesarean section. They divided into three groups: those having normal placental function, those with an undefinable degree of placental insufficiency, and emergencies. There was no clinical or biochemical difference in the neonates following induction of anaesthesia with either thiopentone or methohexitone. The clinical condition of neonates born of mothers with normal placental function was superior to the other two groups.