الفهرس 
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Abstract
Spinal anaesthesia is often the anaesthetic of choice in caesarean deliveries because it avoids the maternal risk of general anaesthesia. However, hypotension during spinal anaesthesia can have deleterious effects on both mother and neonate. In the case of patients with preeclampsia, these women are less likely to develop spinal-induced hypotension than normotensive women. However, it remains essential to avoid hypotension due to the potential adverse effects on uteroplacental perfusion.
Traditionally, ephedrine has been recommended as the vasopressor of choice for treatment of hypotension after spinal anaesthesia for caesarean delivery. Ephedrine is an indirectly acting α- and β-adrenergic agonist. However, its position has been challenged because of potential complications, such as fetal acidosis. It is still used by the majority of anaesthesiologists for control of hypotension in certain situations.
Phenylephrine is established as a preferred first-line vasopressor for maintaining blood pressure during spinal anaesthesia for cesarean delivery. Ephedrine has higher transplacental transfer than phenylephrine. However, because phenylephrine is a pure α-adrenergic agonist, its use is often associated with a reflex decrease in heart rate and an associated decrease in cardiac output. As a result, this has encouraged the investigation of alternative agents such as norepinephrine.
The results from available clinical trials that have studied the use of vasopressors to rescue spinal hypotension in parturients with preeclampsia used bolus phenylephrine or ephedrine and have shown that phenylephrine administration restored mean arterial pressure, but not did not significantly increase maternal cardiac output. Small doses of ephedrine can also be used, which may restore spinal-induced decrease of peripheral vascular resistance and provide a favorable effect on uteroplacental circulation. Comparative studies have shown that phenylephrine and ephedrine were similarly effective in rescuing spinal hypotension, with no differences observed in neonate Apgar scores and umbilical artery pH in the presence of uteroplacental insufficiency. However, phenylephrine might present more favorable base excess and umbilical artery oxygen saturation compared with ephedrine. Despite extensive research, it remains unclear which drug is the better choice for the management of women with preeclampsia
Norepinephrine is similar to phenylephrine in being a potent α-adrenergic agonist, but in addition norepinephrine also possesses weak β-adrenergic agonist activity. The latter counteracts the reflex slowing of heart rate, which potentially may result in a more stable cardiac output when norepinephrine is used to maintain blood pressure during spinal anaesthesia.
The study included 60 pregnant women with mild preeclampsia scheduled for caesarean delivery under spinal anaesthesia, who showed a decrease in systolic blood pressure <80% of baseline; they were divided into 3 groups (20 patients each) and they received boluses of the following drugs to treat hypotension:
• group E: patients received ephedrine (6 mg).
• group N: patients received norepinephrine (5 µg).
• group P: patients received phenylephrine (50 µg).
The results of this study showed that:
Age, Weight, and Height
The mean age was 26.80 ± 6.54 years, 28.84 ± 5.81 years and 29.9 ± 7.26 years for groups E, N and P respectively.
The mean weight was 79.85 ± 10.47 kg, 77.83 ± 9.48 kg, and 78.45 ± 7.91 kg for groups E, N and P respectively.
The mean height was 161.35 ± 8.11 cm, 162.35 ± 7.59 cm, 161.75 ± 5.44 cm for groups E, N and P respectively.
There were no statistically significant differences between the three studies groups regarding age, weight and height.
Highest level of sensory block and spinal anaesthesia to delivery interval
The highest level of sensory block ranged from T3 to T4 in the three studies groups, with no statistically significant difference between them.
The mean spinal anaesthesia to delivery interval was 11.07 ± 1.62 minutes, 10.99 ± 1.72 minutes and 11.13 ± 1.87 minutes in groups E, N and P respectively. There was no statistically significant difference between the three groups regarding the spinal anaesthesia to delivery interval.
Haemodynamic Parameters
• Systolic blood pressure
The SBP was significantly higher in group N compared to group E after 12 min and after 13 min. At delivery, the SBP was significantly higher in group N compared to group E, as well as 5–30 min after delivery.
The SBP was significantly higher in group P than group E after 10 min, after 11 min, after 12 min and after 13 min. At delivery, the SBP was significantly higher in group P compared to group E, as well as 5–30 min after delivery.
There were no significant intergroup differences in SBP between groups N and P throughout the study period.
• Heart rate
The HR was significantly higher in group E compared to group N after 4–12 min. At delivery, the HR was significantly higher in group E compared to group N, as well as 5–30 min after delivery.
The HR was significantly higher in group E compared to group P after spinal anaesthesia, after 1 min, 2 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min and 13 min. At delivery, the HR was significantly higher in group E compared to group P, as well as 5–30 min after delivery.
The HR was significantly lower in group N compared to group P after 1 and 2 min, and significantly higher in group N compared to group P after 8, 9, 10 and 11 min. There were no intergroup differences in HR between groups N and P at and after delivery.
• Cardiac output
The CO was not significantly different between groups E and N.
It was significantly higher in group E compared to group P at 12 min.
It was significantly lower in group P compared to group N at 2, 3, 4, 5, 8, 10, 11 and 12 min, and at delivery, and 5–30 min after delivery.
• Stroke volume
The SV was significantly lower in group E compared to group N after 3–12 min and at delivery, and 5–30 min after delivery.
It was significantly lower in group E compared to group P after 1, 2 and 7 min, and at delivery, 15, 20 and 25 min after delivery.
It was significantly lower in group P compared to group N after 1–10 min, and at delivery, and 5–25 min after delivery.
• Systemic vascular resistance
The SVR was not significantly different between groups E and N throughout the study period.
It was significantly lower in group E compared to group P after 8–13 min, and at delivery and 5–30 min after delivery.
It was significantly higher in group P compared to group N after 2, 7, 8, 9, 10, 11 and 12 min, and at delivery and 5–30 min after delivery.
Neonatal outcome
There were no significant intergroup differences regarding UA or UV PCO2 or PO2; or in Apgar scores at 1 min and at 5 min. However, UA and UV pH and HCO3 were significantly lower in group E compared to groups N and P.
Maternal side effects
Maternal nausea and vomiting were scored on a scale of 0–2, where 0 is no nausea; 1 is nausea but no vomiting; and 2 is nausea and vomiting.
In group E, 16 cases scored 0, 2 cases scored 1 and 2 cases scored 2.
In group N, 19 cases scored 0, and 1 case scored 1, with no cases scoring 2.
In group P, 18 cases score 0, 1 case scored 1, and 1 case scored 2.
There were no cases in where there was a change in the level of consciousness of the mother in any of the groups, and no cases in where hypertension (defined as SBP > 120% of the baseline level) in any of the groups.
There were no cases that required atropine in group E, 1 case required atropine in group N, and 4 cases required atropine in group P.