Spinal Anesthesia-Induced Hypotension: A Risk Comparison Between Patients with Severe Preeclampsia and Healthy Women Undergoing Preterm Cesarean Delivery

Abstract

We previously showed that, in comparison with term healthy parturients, patients with severe preeclampsia had a less frequent incidence of spinal hypotension, which was less severe and required less ephedrine. In the present study, we hypothesized that these findings were attributable to preeclampsia-associated factors rather than to a smaller uterine mass. The incidence and severity of hypotension were compared between severe preeclamptics (n = 65) and parturients with preterm pregnancies (n = 71), undergoing spinal anesthesia for cesarean delivery (0.5% bupivacaine, sufentanil, morphine). Hypotension was defined as the need for ephedrine (systolic blood pressure <100 mm Hg in parturients with preterm fetuses or 30% decrease in mean blood pressure in both groups). Apgar scores and umbilical arterial blood pH were also studied. Neonatal and placental weights were similar between the groups. Hypotension was less frequent in preeclamptic patients than in women with preterm pregnancies (24.6% versus 40.8%, respectively, P = 0.044). Although the magnitude of the decrease in systolic, diastolic, and mean arterial blood pressure was similar between groups, preeclamptic patients required less ephedrine than women in the preterm group to restore blood pressure to baseline levels (9.8 +/- 4.6 mg versus 15.8 +/- 6.2 mg, respectively, P = 0.031). The risk of hypotension in the preeclamptic group was almost 2 times less than that in the preterm group (relative risk = 0.603; 95% confidence interval, 0.362-1.003; P = 0.044). The impact of Apgar scores was minor, and umbilical arterial blood pH was not affected. We conclude that preeclampsia-associated factors, rather than a smaller uterine mass, account for the infrequent incidence of spinal hypotension in preeclamptic patients.

Fluid and vasopressor management for Cesarean delivery under spinal anesthesia: Continuing Professional Development

“…53 Except for the usual contra-indications of neuraxial anesthesia, spinal anesthesia involving usual clinical doses of bupivacaine is now regarded as a safe approach for pre-eclamptic patients requiring Cesarean delivery. [53][54][55][56][57] Experimental data show that the incidence of hypotension induced by the spinal anesthestic and the requirement for vasopressors are reduced in this population compared with healthy parturients. 54,55 Although spinal blockade is responsible for an approximately 20% decrease in systolic blood pressure, both in healthy parturients and pre-eclamptic patients, blood pressure values meeting the definition of arterial hypotension are seen less frequently in pre-ecamptic patients, therefore treatment is required less often.…”

“…[53][54][55][56][57] Experimental data show that the incidence of hypotension induced by the spinal anesthestic and the requirement for vasopressors are reduced in this population compared with healthy parturients. 54,55 Although spinal blockade is responsible for an approximately 20% decrease in systolic blood pressure, both in healthy parturients and pre-eclamptic patients, blood pressure values meeting the definition of arterial hypotension are seen less frequently in pre-ecamptic patients, therefore treatment is required less often. Moreover, sympathetic blockade causes only a modest decrease in peripheral vascular resistance in pre-eclamptic women, and this may explain the lower incidence of hypotension in these patients.…”

“…[54][55][56]58 As the intravascular compartment may be contracted in this condition, it is suggested that selected patients (especially those with oliguria) may benefit from moderate volume loading. 55 However, pulmonary edema is the most frequent complication in this patient population, in part because of altered pulmonary capillary permeability associated with pre-eclampsia; so cautious volume loading is advised. 53,59 Therefore, in pre-eclamptics receiving spinal anesthesia, intravascular fluid loading not exceeding 5 to 10 mLÁkg -1 may be indicated, depending on the clinical situation.…”

“…53 Hormis les contre-indications habituelles de l'anesthésie neuraxiale, il est maintenant accepté qu'une rachianesthésie comprenant des doses de bupivacaïne normalement utilisées en clinique constitue une approche sécuritaire chez les pré-éclamptiques nécessitant une césarienne. [53][54][55][56][57] Les données expérimentales démontrent que l'incidence d'hypotension artérielle induite par la rachianesthésie ainsi que les besoins en vasopresseurs sont moindres dans cette population que chez les parturientes normales. 54,55 Bien que le bloc rachidien entraîne une diminution d'environ 20 % de la tension artérielle systolique tant chez les parturientes en santé que chez les patientes pré-éclamptiques, moins de femmes dans cette dernière population présentent des valeurs de tensions artérielles systoliques compatibles avec la définition d'hypotension artérielle et donc nécessitent un traitement.…”

“…[53][54][55][56][57] Les données expérimentales démontrent que l'incidence d'hypotension artérielle induite par la rachianesthésie ainsi que les besoins en vasopresseurs sont moindres dans cette population que chez les parturientes normales. 54,55 Bien que le bloc rachidien entraîne une diminution d'environ 20 % de la tension artérielle systolique tant chez les parturientes en santé que chez les patientes pré-éclamptiques, moins de femmes dans cette dernière population présentent des valeurs de tensions artérielles systoliques compatibles avec la définition d'hypotension artérielle et donc nécessitent un traitement. Par ailleurs, ces résultats sont possiblement corrélés au fait que le bloc sympathique n'entraîne qu'une faible diminution des résistances vasculaires périphériques chez les femmes pré-éclamptiques.…”