Minimum alveolar concentration of halothane and enflurane are decreased in early pregnancy

Oestrous cycle affects emergence from anaesthesia with dexmedetomidine, but not propofol, isoflurane, or sevoflurane, in female rats

BACKGROUND

Although sex differences in anaesthetic sensitivity have been reported, what underlies these differences is unknown. In rodents, one source of variability in females is the oestrous cycle. Here we test the hypothesis that the oestrous cycle impacts emergence from general anaesthesia.

METHODS

Time to emergence was measured after isoflurane (2 vol% for 1 h), sevoflurane (3 vol% for 20 min), dexmedetomidine (50 μg kg^-1 i.v., infused over 10 min), or propofol (10 mg kg^-1 i.v. bolus) during proestrus, oestrus, early dioestrus, and late dioestrus in female Sprague-Dawley rats (n=24). EEG recordings were taken during each test for power spectral analysis. Serum was analysed for 17β-oestradiol and progesterone concentrations. The effect of oestrous cycle stage on return of righting latency was assessed using a mixed model. The association between righting latency and serum hormone concentration was tested by linear regression. Mean arterial blood pressure and arterial blood gases were assessed in a subset of rats after dexmedetomidine and compared in a mixed model.

RESULTS

Oestrous cycle did not affect righting latency after isoflurane, sevoflurane, or propofol. When in the early dioestrus stage, rats emerged more rapidly from dexmedetomidine than in the proestrus (P=0.0042) or late dioestrus (P=0.0230) stage and showed reduced overall power in frontal EEG spectra 30 min after dexmedetomidine (P=0.0049). 17β-Oestradiol and progesterone serum concentrations did not correlate with righting latency. Oestrous cycle did not affect mean arterial blood pressure or blood gases during dexmedetomidine.

CONCLUSIONS

In female rats, the oestrous cycle significantly impacts emergence from dexmedetomidine-induced unconsciousness. However, 17β-oestradiol and progesterone serum concentrations do not correlate with the observed changes.

Association of menstrual cycle and postoperative quality of recovery in premenopausal women: a prospective cohort study

Background

Women have poorer quality of postoperative recovery from general anaesthesia than men. This persists for at least 3 days postoperatively, and is more pronounced in premenopausal women. Studies of menstrual cycle effects on pain or postoperative nausea and vomiting report conflicting results. Our aim was to determine whether menstrual cycle phase is associated with quality of recovery after surgery in premenopausal women.

Methods

Eligible women aged 18-45 yr undergoing wisdom teeth extraction or laparoscopic cholecystectomy under general anaesthesia with volatile agents were recruited from Epworth HealthCare Richmond in Melbourne, Australia from 2019 to 2021. Menstrual history and progesterone levels were used to determine cycle phase (luteal or non-luteal). Linear mixed and generalised linear regression models were fitted to examine differences in Quality of Recovery-15 (QoR-15) score on postoperative days 1 (primary outcome) and 3, and secondary outcomes (pain, analgesic effectiveness, postoperative nausea and vomiting, prolonged hospital admission), between groups, adjusting for confounders.

Results

A total of 177 women were recruited (74 luteal, 103 non-luteal). Six (3%) underwent laparoscopic cholecystectomy. Estimated mean differences (95% confidence interval; P-value) in adjusted QoR-15 scores between luteal and non-luteal groups were -0.05 (-5.86 to 5.76; P=0.986) and 1.40 (-4.41 to 7.21; P=0.636) on postoperative days 1 and 3, respectively. Secondary outcomes were not different between groups.

Conclusions

There was no significant difference in postoperative QoR-15 score or other outcomes between women in the luteal and non-luteal phases of their cycle. Women can be reassured that cycle phase does not impact postoperative quality of recovery when undergoing minor surgery under general anaesthesia.

Clinical trial registration

ACTRN12618000240246.

An update on the physiologic changes during pregnancy and their impact on drug pharmacokinetics and pharmacogenomics

For many years, the medical community has relied in clinical practice on historic data about the physiological changes that occur during pregnancy. However, some newer studies have disputed a number of assumptions in these data for not being evidence-based or derived from large prospective cohort-studies. Accurate knowledge of these physiological changes is important for three reasons: Firstly, it facilitates correct diagnosis of diseases during pregnancy; secondly, it enables us to answer questions about the effects of medication during pregnancy and the ways in which pregnancy alters pharmacokinetic and drug-effects; and thirdly, it allows for proper modeling of physiologically-based pharmacokinetic models, which are increasingly used to predict gestation-specific changes and drug-drug interactions, as well as develop new knowledge on the mode-of-action of drugs, the mechanisms underlying their interactions, and any adverse effects following drug exposure. This paper reviews new evidence regarding the physiologic changes during pregnancy in relation to existing knowledge.

Managing Heart Disease in Pregnancy

Cardiac disease is an important cause of mortality in pregnancy. It has the potential to remain undiagnosed and may present with cardiovascular decompensation during pregnancy, at the time of delivery, or immediately postpartum. It can have long-term implications to the life of the affected women and their families. This review summarises the current knowledge of the incidence, prevalence, and management of pregnancy-related cardiovascular disease in women presenting preconceptionally or during pregnancy.

Male requires a higher median target effect-site concentration of propofol for I-gel placement when combined with dexmedetomidine

OBJECTIVE

The supraglottic airway device (SAD) can be used for airway management of spontaneous breathing patients, and propofol is commonly applied for the SAD placement. This study was designed to assess the effect of gender on median target effect-site concentration (Ce₅₀) of propofol for I-gel placement when combined with dexmedetomidine.

MATERIAL AND METHOD

19 males and 18 females, aged 18 to 59 and undergoing elective surgery, were enrolled. After intravenous infusion of dexmedetomidine 1.0μg/kg over 10min followed by continuous infusion of 0.4μg/kg/h, target-controlled infusion of propofol under Marsh model was started and the initial Ce of propofol was set at 4.79μg/mL and 4.35μg/mL in the male and female patients, respectively. The I-gel was inserted when the Ce of propofol reached the pre-set concentration and bispectral index value was less than 60. The Ce of propofol required for I-gel placement was determined by the Dixon up-and-down method.

RESULTS

The Ce₅₀ (95% confidence interval) of propofol required for I-gel placement were 4.082μg/mL (3.798-4.332μg/mL) and 3.509μg/mL (3.266-3.749μg/mL) in male and female patients, respectively, with a significantly higher Ce₅₀ in males.

CONCLUSION

When combined with dexmedetomidine, males require a higher Ce₅₀ of propofol for I-gel placement compared to females.

Physiological and anatomical changes of pregnancy: Implications for anaesthesia

During pregnancy, the body goes through various anatomical and physiological changes to provide suitable environment for foetal development, to cater to the increased metabolic demands and to prepare for the childbirth. These changes have notable anaesthetic implications in determining the optimal anaesthetic technique, while also keeping in mind the gestational age, type of procedure and any coexisting medical condition. It is important to note that these changes revert to baseline (pre-pregnancy) levels at different time intervals during the postpartum period which is important while managing postpartum patients. None of the anaesthetic agents are known teratogens; however, there is concern regarding the effects of some agents on the developing brain.

Sex and gender aspects in anesthetics and pain medication

The influence of sex and gender on anesthesia and analgesic therapy remains poorly understood, nevertheless the numerous physiological and pharmacological differences present between men and women. Although in anesthesiology sex-gender aspects have attracted little attention, it has been reported that women have a greater sensitivity to the non-depolarizing neuroblocking agents, whereas males are more sensitive than females to propofol. It has been suggested that men wake slower than women after general anesthesia and have less postoperative nausea and vomiting. Sexual hormones seem to be of importance in the onset of differences. Nevertheless, in the last years, sex-gender influences on pain and analgesia have become a hot topic and data regarding sex-gender differences in response to pharmacologic and non-pharmacologic pain treatments are still scanty, inconsistent, and non-univocal. In particular, females seem to be more sensitive than males to opioid receptor agonists. Women may experience respiratory depression and other adverse effects more easily if they are given the same doses as males. Evidently, there is an obvious need for more research, which should include psychological and social factors in experimental preclinical and clinical paradigms in view of their importance on pain mechanism, in order to individualize analgesia to optimize pain relief.

Comparison of enflurane and propofol in electroconvulsive therapy, a randomized crossover open preliminary study on seizure duration and anaesthetic recovery

BACKGROUND AND OBJECTIVES

Electroconvulsive therapy (ECT) is commonly used for treatment of depression, mania and affective disorders. Anaesthetics for general anaesthesia during ECT should have rapid onset, rapid emerge, not interfere with seizure activity and not shorten seizure duration. The aim of this study is to compare effects of enflurane, a pro-convulsive anaesthetic agent, and propofol on seizure durations, postictal suppression index and recovery times during electroconvulsive therapy.

METHODS

Unpremedicated subjects were divided into two groups according to induction of anaesthesia. Patients were induced for ECT with 5% enflurane in group E and 1.2mg.kg(-1) propofol in group P until loss of consciousness. The durations of electroencephalogram (EEG) and motor seizures, postictal suppression index, time to spontaneous breathing, duration of eye opening, and obeying commands were recorded.

RESULTS

There was no statistically significant difference between the groups regarding motor and EEG seizure times and postictal suppression index on the EEG records. Recovery times (times of starting spontaneous breathing, eye opening, and obeying command) were significantly shorter in group E compared to group P. No nausea or vomiting were observed and no ECG abnormality was noted except transient sinus bradycardia and sinus tachycardia.

CONCLUSIONS

Although sufficient seizure for the treatment was provided during enflurane anaesthesia, any additional benefit was not revealed regarding seizure times or postictal suppression index when compared to propofol anaesthesia. On the other hand, recovery times after enflurane anaesthesia were shorter than propofol anaesthesia. However, there is still a need for further study in different ETCO(2) levels.

Clinical therapeutics in pregnancy

Most drugs are not tested for use during pregnancy, consequently, labeling, which may include information about fetal safety, includes nothing about dosing, efficacy, or maternal safety. Yet these are concerns of health care providers considering treatment of disease during pregnancy. Therefore, the practitioner treats the pregnant woman with the same dose recommended for use in adults (typically men) or may decide not to treat the disease at all. However, is the choice of not treating a woman during pregnancy better than dealing with the challenges which accompany treatment? This paper, which summarizes metabolic and physiologic changes induced by pregnancy, illustrates that standard adult dosing is likely to be incorrect during pregnancy.

Patient Sex and its Influence on General Anaesthesia

Physiological and pharmacological differences exist between men and women. Women wake faster than men following general anaesthesia. Women also differ from men in their postoperative recovery as reflected by differences in postoperative pain, nausea and vomiting and overall quality of recovery. These gender differences seem to be more pronounced in premenopausal women, suggesting hormonal mechanisms are a major contributing factor.

Effects of Pregnancy on the Solubility of Halogenated Volatile Anaesthetics in Rat Blood and Tissues

This study was designed to evaluate the effects of pregnancy on the solubility of halogenated volatile anaesthetics in rat blood and tissues. Tissue samples from 10 pregnant and 10 non-pregnant adult female Sprague Dawley rats, including the heart, liver, kidney and brain, were obtained and made into respective homogenates. Blood/gas and tissue/gas partition coefficients for halothane, sevoflurane and isoflurane were determined by the method of two-stage headspace equilibration by gas chromatography with each of the homogenates. Values were analysed by t-test or one-way analysis of variance. The solubility within blood and brain for halothane in the pregnant group (2.90 ± 0.44, 5.55 ± 0.73) was significantly lower than that of the non-pregnant group (3.42±0.23, 6.33±0.64; P <0.05). However, there were no significant differences between the two groups for liver, kidney or heart solubility. For sevoflurane and isoflurane, there were no significant differences in solubility between the two groups. In conclusion, pregnancy decreased the solubility of halothane within the blood and brain, whereas the solubility of halothane in other tissues including the liver, kidney and heart showed no significant alteration. Pregnancy did not affect the solubility of sevoflurane or isoflurane within blood or the other tissues studied.

Association of ethnicity with the minimum alveolar concentration of sevoflurane

BACKGROUND

Selective breeding produces animal strains with varying anesthetic sensitivity. It thus seems unlikely that various human ethnicities have identical anesthetic requirements. Therefore, the authors tested the hypothesis that the minimum alveolar concentration of sevoflurane differs significantly as a function of ethnicity.

METHODS

The authors recruited 90 American Society of Anesthesiologists physical status I and II adult patients belonging to three Jewish ethnic groups: European, Oriental, and Caucasian (from the Caucasus Mountain region). All were scheduled to undergo surgery requiring a skin incision exceeding 3 cm. Without premedication, anesthesia was induced with 6-8% sevoflurane in 100% oxygen, and tracheal intubation was facilitated with succinylcholine. The skin incision was made after a predetermined end-tidal concentration of sevoflurane of 2.0% was maintained for at least 10 min in the first patient in each group. Blinded investigators observed the patient for movement during the subsequent minute. The concentration in the next patient was increased by 0.2% when patients moved, or decreased by the same amount when they did not. Results are presented as means [95% confidence intervals].

RESULTS

Morphometric and demographic characteristics were similar among the groups; however, mean arterial pressure was slightly greater in European Jews. Minimum alveolar concentration for sevoflurane was greatest in Caucasian Jews (2.32% [2.27-2.41%]), less in Oriental Jews (2.14% [2.06-2.22%]), and still less in European Jews (1.9% [1.82-1.99%]) (P < 0.001).

CONCLUSIONS

The results suggest that minimum alveolar concentration varies as a function of ethnicity. However, the extent to which confounding characteristics contribute, including lifestyle choices and environmental factors, remains unknown.

Gender and recovery after general anesthesia combined with neuromuscular blocking drugs

Previous studies suggest that women recover faster from general anesthesia than men, but it is unclear whether this is a result of a gender effect or differences in the pattern of drug administration or type of surgery. We performed a subset analysis comparing recovery characteristics from general anesthesia combined with neuromuscular blocking drugs of female and male patients, at risk of awareness, enrolled in a large trial testing the effectiveness of bispectral index (BIS) monitoring. We used multivariate statistical methods to adjust for differences in baseline characteristics, duration and extent of surgery, and anesthetic drug administration in 1079 patients (584 male, 495 female). Female patients had higher BIS values than male patients despite similar amounts of anesthetic drug administration (time-averaged mean [sd] BIS: male 44.6 [7.1] versus female 46.4 [6.6]; P = 0.005). Time to eye opening after anesthesia and time to eligibility to discharge from the postanesthesia care unit were less in women than men (male 13.9 [13.2] min versus female 10.6 [11.6] min; P < 0.001; male 133 [209] min versus female 78 [106] min; P < 0.001, respectively). These differences persisted after multivariate adjustment (both P < or = 0.001). Gender has an independent effect on recovery times in patients undergoing general anesthesia combined with neuromuscular blocking drugs, with women recovering faster than men. Higher BIS values during maintenance of anesthesia in women, despite similar amounts of anesthetic drug administration, suggests that women are less sensitive to the hypnotic effect of anesthetic drugs than men and may help explain faster recovery times in women.

Rat Intubation and Ventilation for Surgical Research

Effective outcomes in cardiothoracic surgical research using rodents are dependent upon adequate techniques for intubation and mechanical ventilation. Multiple methods are available for intubation of the rat; however, not all techniques are appropriate for survival studies. This article presents a refinement of intubation techniques and a simplified mechanical ventilation setup necessary for intrathoracic surgical procedures using volatile anesthetics. The procedure is defined and complications of the procedure are elucidated that provide a justification for animal numbers needed for initiating new studies. Lewis rats weighing 178-400 g (287 +/- 44) were anesthetized using Enflurane and intubated with a 16-G angiocatheter using transillumination. Mechanical ventilation (85 bpm, 2.5 mL TV, enflurane 1.5-2%) maintained adequate sedation for completion of an intrathoracic procedure. Complications of the intubation and ventilation included mortality from anesthetic overdose, intubation difficulty, pneumothorax, traumatic extubation, and ventilation disconnection. Anesthetic agents and their related effects on the rat heart and reflexes are compared. This article also underscores the importance of refinement, reduction, and replacement in the context of cardiothoracic surgery using rodent models.

Determining Minimum Alveolar Anesthetic Concentration of Halothane in Rats: The Effect of Incremental Change in Halothane Concentration and Number of Crossovers

Computer simulations for the technique of estimating minimum alveolar anesthetic concentration (MAC) in patients (quantal design) suggest that incremental concentration changes and the number of crossovers affect MAC. We hypothesized that these variables may also apply to estimating MAC in rats (bracketing design). This study tested that hypothesis and also examined whether these variables might mask differences in MAC between groups in which MAC might be expected to differ (pregnant [P] versus nonpregnant [NP]). There were 2 cohorts (n = 27 and n = 30 rats). Each cohort included NP females, females in early P, and females in late P. MAC was tested by using an incremental concentration change of 0.20% and one within-subject crossover in the first cohort and by using an increment size of 0.10% and four crossovers in the second cohort. MAC was statistically significantly increased in the three groups in the second cohort (NP, 1.16 +/- 0.12; early P, 1.14 +/- 0.10; late P, 1.07 +/- 0.10; mean +/- sd) compared with values in the three comparable groups in the first cohort (NP, 0.95 +/- 0.06; early P, 1.01 +/- 0.09; late P, 0.93 +/- 0.13). Values did not differ among groups within each cohort. Post hoc simulations indicated that up to 36% of the difference between cohorts was due to increment size, with the balance due to experimental factors. Our findings confirmed the hypothesis that increment size affects estimates of MAC when a bracketing design is used.

Fetal endoscopic surgery: indications and anaesthetic management

Fetal intervention for certain life-threatening conditions has progressed from being primarily experimental in nature to the standard of care in certain circumstances. While surgical techniques have advanced over the past few years, the anaesthetic goals for these interventions have remained the same; namely, minimizing maternal and fetal risk as well as maximizing the chances of a successful fetal intervention and optimize the conditions necessary to carry the fetus to term gestation. Fetal endoscopic techniques allow access to the fetus without the need for a hysterotomy incision, thus improving the chances of controlled post-operative tocolysis and term gestation after fetal intervention. This procedure, however, is not without associated risks to both fetus and mother. This chapter will address the fetal diseases that may benefit from fetoscopic intervention, the rationale behind why maternal and fetal anaesthesia is required, the various anaesthetics used for these cases and specific considerations of both maternal and fetal physiology that aid in the determination of the best anaesthetic technique for individual cases. Methods of intra-operative fetal monitoring and fetal resuscitation will also be discussed.

Anesthesia for fetal surgery

Fetal surgery is a rapidly growing and evolving area. Fetal surgery is based on years of animal and clinical research. In contrast, anesthesia techniques for fetal surgery are based on clinical experience. The techniques that have emerged are safe for mother and fetus. In this review, the authors describe current techniques for anesthetic management of fetal surgery patients. General anesthesia is the primary technique used for hysterotomy based surgical correction of midgestation fetuses and ex utero interpartum corrections of end-gestation fetuses. Epidural analgesia, with general anesthesia as back-up, is the primary technique used for fetoscopic cases in which anesthetic care is required. Because of the myriad of anesthetic and surgical issues these cases generate, it is essential to have good communication and cooperation between surgeons and anesthesiologists from the preoperative period to the postoperative period. This will allow development of a cohesive anesthetic and surgical plan that can be used for the safe perioperative management of the fetal surgery patient.

Sevoflurane analgesia in obstetrics: a pilot study

Continuous and intermittent administration of inhalational anesthetics has been successfully employed for treating pain during labor. We conjectured that intermittent sevoflurane administration would be effective for pain relief during labor without side effects to the mother or fetus. Fifty parturients breathed a mixture of 2-3% sevoflurane, oxygen and air before each uterine contraction began. The patients assessed the quality of analgesia by using a visual analogue scale (0-10) before the administration of sevoflurane and after each uterine contraction. All parturients but one were satisfied, demonstrating a mean visual analogue score before and after sevoflurane administration of 8.7 +/- 1.1 and 3.3 +/- 1.5, respectively. Apgar scores at 1 and 5 min were 9 (range 5-9) and 10 (range 8-10), respectively. Our findings suggest that sevoflurane could be effective for the treatment of labor pain.

Anesthesia for nonobstetric surgery in the pregnant patient

Each year over 75,000 pregnant women in the United States undergo nonobstetric surgery. The operations include those directly related to pregnancy, such as cerclage, those indirectly related to pregnancy, such as ovarian cystectomy, and those unrelated to gestation, such as appendectomy. When a pregnant woman presents for surgery, it is a stressful event for everyone involved. Issues about the surgical problem itself often seem secondary to maternal (and physician) concerns about the effect of surgery and anesthesia on the developing fetus, or the potential to trigger preterm labor. This article reviews the physiologic and anatomic changes that affect anesthetic care during pregnancy. The author also reviews the effects of anesthetic drugs and perioperative events on the fetus and on the pregnancy outcome. The relatively small number of published series are reviewed as well as the controversial recommendations regarding fetal and maternal monitoring during surgery.

Early pregnancy does not reduce the C(50) of propofol for loss of consciousness

Requirements for inhaled anesthetics decrease during pregnancy. There are no published data, however, regarding propofol requirements in these patients. Because propofol is often used for induction of general anesthesia when surgery is necessary in early pregnancy, we investigated whether early pregnancy reduces the requirement of propofol for loss of consciousness using a computer-assisted target-controlled infusion (TCI). Propofol was administered using TCI to provide stable concentrations and to allow equilibration between blood and effect-site (central compartment) concentrations. Randomly selected target concentrations of propofol (1.5-4.5 microg/mL) were administered to both pregnant women (n = 36) who were scheduled for pregnancy termination and nonpregnant women (n = 36) who were scheduled for elective orthopedic or otorhinolaryngologic surgery. The median gestation of the pregnant women was 8 wk (range, 6-12 wk). Venous blood samples for analysis of the serum propofol concentration were taken at 3 min and 8 min after equilibration of the propofol concentration. After a 10-min equilibration period of the predetermined propofol blood concentration, a verbal command to open their eyes was given to the patients twice, accompanied by rubbing of their shoulders. Serum propofol concentrations at which 50% of the patients did not respond to verbal commands (C(50) for loss of consciousness) were determined by logistic regression. There was no significant difference in C(50) +/- SE of propofol for loss of consciousness between the Nonpregnant (2.1 +/- 0.2 microg/mL) and Pregnant (2.0 +/- 0.2 microg/mL) groups. These results indicate that early pregnancy does not decrease the concentration of propofol required for loss of consciousness.

IMPLICATIONS

The C(50) of propofol for loss of consciousness in early pregnancy did not differ from that in nonpregnant women, indicating that there is no need to decrease the propofol concentration for loss of consciousness when inducing general anesthesia for termination of pregnancy.

Age, minimum alveolar anesthetic concentration, and minimum alveolar anesthetic concentration-awake

Two defining effects of inhaled anesthetics (immobility in the face of noxious stimulation, and absence of memory) correlate with the end-tidal concentrations of the anesthetics. Such defining effects are characterized as MAC (the concentration producing immobility in 50% of patients subjected to a noxious stimulus) and MAC-Awake (the concentration suppressing appropriate response to command in 50% of patients; memory is usually lost at MAC-Awake). If the concentrations are monitored and corrected for the effects of age and temperature, the concentrations may be displayed as multiples of MAC for a standard age, usually 40 yr. This article provides an algorithm that might be used to produce such a display, including provision of an estimate of the effect of nitrous oxide.

IMPLICATIONS

Two defining effects of inhaled anesthetics (immobility in the face of noxious stimulation, and absence of memory) correlate with the end-tidal concentrations of the anesthetics. Thus, these defining effects may be monitored and the results displayed if the concentrations are known and corrected for the effects of age and temperature.

Sevoflurance: approaching the ideal inhalational anesthetic. a pharmacologic, pharmacoeconomic, and clinical review

Sevoflurane is a safe and versatile inhalational anesthetic compared with currently available agents. Sevoflurane is useful in adults and children for both induction and maintenance of anesthesia in inpatient and outpatient surgery. Of all currently used anesthetics, the physical, pharmacodynamic, and pharmacokinetic properties of sevoflurane come closest to that of the ideal anesthetic (200). These characteristics include inherent stability, low flammability, non-pungent odor, lack of irritation to airway passages, low blood:gas solubility allowing rapid induction of and emergence from anesthesia, minimal cardiovascular and respiratory side effects, minimal end-organ effects, minimal effect on cerebral blood flow, low reactivity with other drugs, and a vapor pressure and boiling point that enables delivery using standard vaporization techniques. As a result, sevoflurane has become one of the most widely used agents in its class.

Effects of maternal anesthesia in the neonate

All commonly used anesthetic agents and drugs undergo placental transfer. Understanding the placental transfer of anesthetic drugs and their effects on the neonate is essential for optimal administration of both regional and general anesthesia. Regional anesthesia is decidedly safer for the mother and, when properly performed, actually may be beneficial to the stressed neonate. The healthy neonate also benefits from maternal analgesia during labor and delivery. General anesthesia may result in transient neonatal depression, particularly when delivery is of an emergency nature. The skill and knowledge of the anesthesiologist are more important than the type of anesthesia administered. Therefore, when properly performed, both regional and general anesthesia are quite safe in terms of neonatal outcome.