IRB #14499

Genetic variability and hypotension during cesarean section



Determine the effect of b2adrenergic receptor and eNOS genotypes on:

?        severity of hypotension after spinal anesthesia

?        response to ephedrine (b2 agonist) and phenylephrine (a agonist)


Sample size: 200 elective C/S under spinal anesthesia

Exclusion: chronic or pregnancy-induced hypertension, with or without treatment



?        BP (3 measurements) should be recorded 30 minutes after arrival at L&D in supine position with LUD (baseline BP)

?        Fluid preload: 1000ml RL for case starting 8-9 AM; 125 ml additional for every hour after 9 AM

?        Spinal procedure: sitting position (L2-L3, L3-L4, L4-L5), 2.5ml solution (12mg hyperbaric bupivacaine & 25mg fentanyl & 200mg morphine)

?        Stopwatch starts upon beginning of injection of the spinal solution

?        BP, HR, %O2 sat q1 for the first 15 minutes, then q5

?        Anesthetic level to ice q5 according to data collection sheet

?        Record each ephedrine and phenylephrine dose according to timing

?        Record skin incision time, uterotomy, delivery time

?        Record baby weight, Apgar and cord gas (pH)

?        Record staples/completion of skin suture time

?        Blood sample (2 purple top tubes) any time (during C/S, or on PP day 1) labelled with patient name and MRN



?Protocol? for ephedrine/phenylephrine administration

?         Record ?baseline SBP? (mean of 3 measurements pre-op)

?         At each 1 min SBP measurement

?  If decrease > 20% from baseline BP or < 90 mm Hg ? ephedrine 5-15 mg

?  If inadedquate response after ephedrine 30 mg ? phenylephrine 40-80 mg, may repeat ephedrine

?         If hypotension and HR > 120 ? phenylephrine 40-80mg

?         Above doses may be exceeded if clinical conditions warrant--- record all doses)