labor has 2 stages:
first –contraction of the uterus before cevix is fully open—pain is visceral, poorly localised, mediated by C-fibers(thin, no myeline , easy to block), level T10L1 , goes thru sympathetic chain
second—cervix is fully open, baby moves thru vagina—pain is somatic, sharp, mediated by A-delta fibers(thicker, harder to block, pudendal nerve) ,level S2S4,
in order to have pain free labor we need to block both stages
What options we have for pain relief?
3)blocks–paracervical, pudendal (paravertebral –almost never done)
5)epidural/ spinal anesthesia
Lets see which of these option is the best, and which options are not the best , ( i ll tell your a little secret—spinal/epidural is the best–you ll see it)
1)general anesthesia—was used in 1800′s on British queen
you ll sleep and will not feel the pain
disadvantages:—in order to push in 2nd stage you have to be awake—you can not sleep and be awake at the same time(imperfect method)
–makes baby depressed, relaxes uterine contractions(delays labor)(except N2O), pregnant women have full stomach –they may vomit aspirate and die.
2) iv opioids
3)paracervical block (for 1st stage)
a little plan:
thats how its done:
disadvantages—fetal bradicardia, too many babies die, abandoned
pudendal nerve block(for 2nd stage)
—-thats nerves supplying vulva
thats how its done
disadvantages—technical difficulties, infection, bleeding(was done by OBs, basicaly abandoned )
4) TAP blocks—idea to block nerves in abdominal wall
disadvantages—proven worse then intrathecal Morphine,(do i have to continue?), you need to stick needle in the belly, on both sides(why to stick extra needle when spinal already there?)(imagine doing it 2am on 400 lbs mama), doses of Local anesthetics are close to toxic,
5)combined spinal epidural is the best. why?