Obstetrics

• With meconium, it is no longer recommended to do intrapartum suctioning of newborn

• The main recommendation is necessary pre- and post-op monitoring of fetus during surgery

• Lung volumes are easy. Basically TLC decreases 5% and VC doesn't change. VT increases and IRV doesn't change. So RV + ERV = FRC must decrease ~20%.

• Chlorprocaine is used because fastest onset, fastest breakdown (so less worry about toxicity). 21 secs in maternal blood and 2 min even with pseudocholinesterase deficiency.

• The most common side effect of intraspinal narcotics is pruritus. The next most common side effects are nausea and vomiting, followed by urinary retention. Respiratory depression and headache may occur, but are relatively infrequent 

• Average blood loss in vaginal delivery is 600 and c/s is 1000

• NTG, nitroprusside, and nifedipine all treat HTN but are uterotonic, only labetalol is not.

• Preeclampsia becomes severe if BP 160/110, proteinuria 5 g/24 hr; elevated serum creatinine, urine output of less than 500 mL/24 hr; CNS disturbances (seizures, altered consciousness, headaches, visual disturbances); pulmonary edema; epigastric or right upper quadrant pain; hepatic rupture; impaired liver function; thrombocytopenia; or HELLP syndrome. 

• WBC normally rises to 15000 postpartum day 1

• Paracervical blocks only block the first stage pain. Pudendal blocks block the somatic component during the second stage but not visceral pain of contractions.

• Tocolytics include MgSO4 and/or β-adrenergic agonists (ritodrine, terbutaline) are used. Prostaglandin-synthetase inhibitors (indomethacin, ketorolac) and calcium entry blockers (nifedipine) have recently been used in selected cases. 

• Magnesium therapeutic level is 4-8 Meq/L, loss of tendon reflex at 10, and CV effects at 15

• Aortocaval compression is relevant starting at 20 weeks

• Atropine readily crosses the placenta but at low doses does not seem to cause fetal tachycardia; at high doses, it may produce tachycardia. The combination of neostigmine, which crosses the placenta slightly, and glycopyrrolate, which does not cross the placenta well, has been associated with fetal bradycardia, which is why neostigmine with atropine is preferred when reversing neuromuscular blockers if a fetus is present.

• When EDTA was used, the incidence of severe deep back pain that lasted several hours become noted. This back pain was felt to be related to calcium chelation from the EDTA in the local anesthetic solution that leaked out of the intervertebral foramen and produced hypocalcemic tetany of the paraspinal muscles. Currently, the EDTA has been removed and the chloroprocaine manufactured today is in colored vials to reduce the rate of oxidation