Our analysis could clearly demonstrate a decreased risk of fetal acidosis associated with phenylephrine use. In addition with our findings for BE, this suggests a favorable effect of phenylephrine on fetal outcome parameters. The mechanism of pH depression is not related to pCO(2) .

Background: An effective relief of labour pain has become an important part of obstetric medicine. Therefore regional nerve blocks, systemic analgesic and non-pharmacologic techniques are commonly used. This review article gives a summary of pathophysiology and anatomy of labour pain as well as advantages, disadvantages, risks and adverse reactions of analgesic techniques in newborns and parturients. Methods: We performed a selective literature search in Medline via PubMed using the search-terms ?Analgesia? and ?Obstetrics?. We also included the current guidelines of the German Society for Anesthesiology and Intensive Care Medicine. Results: PDA and CSE are safe techniques for the relief of labour pain if contraindications are excluded. The risk for instrumental delivery but not for caesarean section is increased under neuraxial analgesia. PDA and CSE should be performed in an early stage of labour using low doses of local anaesthetics if possible. It is not necessary to wait for a defined cervical dilatation before starting neuraxial analgesia. Anesthesiologists and obstetricians should inform patients as soon as possible before the situation of stress during labour. Systemic opioid analgesia is a possible alternative for neuraxial techniques. Because of possible side effects systemic remifentanil analgesia should only be performed under continuous monitoring. Several nonpharmacologic methods can also relieve labour pain, but results of studies about their effectiveness are inconsistent.

Topics: Pharmacology, Anesthetic ComplicationsT he choice of vasopressor to treat hypotension due to spinal anesthesia for cesarean section is controversial. For a number of years, the use of a low-dose phenylephrine infusion has been recommended to improve hemodynamic stability. However, evidence to support this recommendation is poor. pH and base excess (BE) are important outcome parameters of the newborn; and 1 systematic review has reported a significantly increased risk of lower pH and BE if ephedrine is used to treat hypotension. However, the clinical significance of this difference is unknown as the pHs reported were within the normal range regardless of whether ephedrine or phenylephrine was used. This meta-analysis was conducted to compare fetal and maternal effects of ephedrine and phenylephrine for spinal anesthesia-induced hypotension.A systematic literature search was conducted for trials comparing ephedrine and phenylephrine for hypotension treatment and the quality of the trials was scored with randomized controlled trials being weighted more in the analysis. The number of events and the total number of subjects in the ephedrine or phenylephrine groups were recorded in addition to instances of maternal hypotension, hypertension, and bradycardia, and instances of fetal acidosis defined as a pH < 7.2. Continuous parameters that were recorded were BE and arterial pCO 2 . The randomeffects model was applied in the analysis of the variables. The pooled risk ratio (RR) and 95% confidence interval (95% CI) and the weighted mean difference (WMD) of the pooled continuous data were calculated. The ephedrine group was chosen as the control group.From 133 articles, 20 were considered for further analysis and included 1069 subjects. The RR of fetal acidosis was 5.29 (95% CI, 1.62-17.25) for ephedrine compared with phenylephrine (P = 0.006). The WMD in pooled BE data was also statistically significantly lower in the ephedrine group (WMD, À1.17; 95% CI, À 2.01 to À0.33; P = 0.006). No significant difference between the 2 agents was found for umbilical artery pCO 2 (WMD, 1.60; 95% CI, À 0.41 to 3.62; P = 0.12). For the studies that reported Apgar values of <7, only 1 neonate in the ephedrine group of 1 study had an Apgar value of <7 after 5 minutes. The 1 study that reported Apgar values at 10 minutes after birth found no statistically significant differences between the ephedrine and phenylephrine groups. The risk of bradycardia was significantly lower in the women in the ephedrine group compared with those in the phenylephrine arm (RR, 0.17; 95% CI, 0.07-0.43). No significant difference was found in the risk of hypotension when the vasopressor was given prophylactically (RR, 1.13; 95% CI, 0.68-1.86; P = 0.64) or in pooled data for the vasopressors for either treatment or prevention (RR, 1.03; 95% CI, 0.72-1.48; P = 0.87). The 2 vasopressors did not differ in the risk of hypertension (RR, 1.18; 95% CI, 0.86-1.63; P = 0.30).These results support the favorable effects of phenylephrine over ephedrine for managing hy...

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