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Barry OB
Question | Answer |
---|---|
Name the 4 stages between oocyte and implantation | Zygote, 4 cell stage(2d), Morula(3d),early blastocyst(4d), implantation(6d) |
Embryonic stage | 3rd week |
fetal stage | 9th week |
1951, Lady Euphame Macalyane | Burned at the stake on castle hill in Edinburgh, Scotland seeking relief from the pains of child birth |
Dr. grupert Lyons, France April, 19, 1836 | ides of magnetizing a woman during child birth, to give brth while asleep. |
John Young Simpson | First OB anesthetic..Ether 19 jan 1847 |
Charles D Meigs | Wrote a Book on OB |
James Young Simpson | Simpson's forceps and book on witch craft |
John Snow | First physician anesthetist, chloroform, queen victoria |
Nathan Keep | 1st OB anesthetic in US Ether 1847 |
Crawford Long | Ether 1842-wife's delivery |
Twighlight sleep | 1900-1940's scopolamine-morphine |
Duke Inhalers contain | Cyprane, Penthrane, N2O & O2 |
Dr. Oskar Kreis | SAB/OB 1900 |
1st C/S with SAB | 1902 |
Einhorn 1905 | Procaine |
1st Pudendal Block | 1908 |
1st Paracervical block | 1926 |
Koller Eye Block | 1884 |
Sinal Anes OB | 1928 |
Cleland 1928 | described pain pathways of uterine contraction |
First reported labor epidural | 1931 |
Lidocaine (year) | 1943 |
% increase in body weight during pregnancy | 17% or 12kg |
Uterus ?kgAmniotic fluid ?kgFetus/Placenta ?kgBlood volume ?kgInterstitial fluid? kgNew fat and protein? kg | Uterus 1kgAmniotic fluid 1 kg Fetus4 kg Placenta 4 kg Blood volume 2 kg Interstitial fluid 2 kgNew fat and protein 4kg |
Pulmonary Anatomic changes | Diaphragm elevation, reduced FRC,capillary engorge. of airways, progesterone induced tracheal and bronchial dilation, cheest expands A/P and transverse diameters |
Pulmonary Physiologic changes | Decreases-airway resis, TPR,TC,ERV, RV, FRC Increases-MV,AV,TV,RR,ILC,O2 consumption No change VC, CC |
In pregnancy base line arterial PO2 increase/decrease by ?mmHg?Arterial PH?Arterial PCO2? | APO2 ^10mmHg. APH no change. APCO2 decrease by 10mmHg ABG:chronic hypervent/resp alk |
Closing volume | lung volume during expiration at which airways begin to close in dependant zones of the lungs |
In supine position what happens to a preg. womans closing volume | closing capacity will exceed FRC(dec. 20% supine), which means the mother is at risk for hypoxemia.terminal alveoli perfused but not ventilated(VQ mismatch) |
Progesterone's effect on the respiratory system | sensitizes resp center to CO2, Resp stimulant, reduces airway resistance due to relaxant effect on bronchial smooth muscle |
Ventilatory changes during pregnancy | MV rises 19-50% by term RR ^9%TV ^28%O2 consumption ^40-60% |
The oxy hb curve shifts R/L during a normal pregnancy | Right, facilitates O2 unloading to fetus |
Additional edema around the airways during pregnancy causes | A smaller more fragile airway, smaller ETT careful suctioning |
In Preeclampsia we can expect the airway | more edematous and edema of the vocal cords |
Hypoxia and Hypercarbia are more pronounced ^O2 demand b/c? | decreased FRC, so decreased O2 storage,& decrease CO when supine |
MAC inc or dec? | decreased 25-40% |
hyperventilation w/ pain during labor inc/dec uterine BF | Uterine BF decreases 25% w/ hypocarbia |
Pain relief during labor does what to oxygenation and ventilation? | normalizes oxygenation and decreases MV and O2 consumption |
RR during pregnancy c/t labor | preg.-15 Labor-22-70 |
TV ml preg vs. labor | preg-480-680 Labor-650-2000 |
MV L/M preg vs. labor | preg.-7.5-10.5 labor-9-30 |
PaCO2 preg vs. Labor | preg- 31mmHg Labor-15-20 |
PaO2 preg vs. Labor | preg-105mmHg Labor-100-108 |
compare preg. abg to non preg | preg. 7.44,30,107,20 non.7.44,40,100,24 |
Significance to the anesthetist | smaller ETT, induction rate increased(MAC, FRC,&RR)decreased O2 reserve |
Maternal hyperventilation Fetal effects | CONSTRICTION UMBILICAL & UTERINE ARTERIES. FETAL ACIDOSIS HYPOCAPNIA MATERNAL HEMOGLOBIN DISSOCIATION CURVE TO THE LEFT (metabolic alkalosis) |
oxy hgb dis curve of the fetus is to the L or R of moms? | left |
CV system BV, CO,SVR changes in preg | increased BV Increased CO(40-50%) due to ^ SV(30%) in 1st half of preg and ^SV and HR(15-20%) in 2nd half..SVR decreased |
Why is the SVR decreased? | ^prostacyclin(vasodilator)progesteronelow resistance placental circulationblood viscosity |
Explain physiological anemia of pregnancy | BV increases 35-50% plasma volume increases 45% and RBC mass only 20%, viscosity is reduced |
T/F RBC and plasma volume continue to increase late into third trimester | True |
There is no change in CVP T/F | True |
in a normal pregnancy Blood pressure is increased 10-20% T/F | false DBP dec.10-20mmHg, SBP dec. 0-15mmHg,MAP dec.15mmHg |
Average EBL at C/S | 500-1000 |
EDG changes during pregnancy | Left axis deviation, minor ST, T and Q wave changes and minor arryhthmias (reversible) |
most common dysrhythmias of pregnancy | premature ectopic atrial and ventricular depolarizations and sinus tachy |
mechanisms for ECG changes in pregnancy | changes in cardiac ion channel conduction,increase in heart size,changes in autonomic tone,hormonal fluxes |
What happens to SV, HR, CO when transitioning from supine in the first stage of labor to lithotomy in the second stage during contractions | SV decreases dramatically, CO decreases and HR increases |
2 components of aortocaval compression | IVC compression and aortoilliac obstruction |
IVC compression | after 24 weeks gest. alternative circulation azygous vein/paravertebral system**compensatory decrease in sympathetic tone and HR |
aortoilliac compression | **arterial side compressionNO maternal symptomsplacental BF decreasesFemoral flow vs. Brachial flow-BP normal in arm, low in femoral, causing early or late decells in baby |
Changes in blood constituents | plasma protein decreases so colloid osm. pressure decreases.leukocyte count increases 12k-20k. All factors increase xcept XI and XIII. enhanced fibrinolysis |
Effects of Blood constituent changes | pulm edema, drug sesitivity, high risk of DVT and PE |
mendelsons recommendations | withhold all food during laborgreater use of regionalsantacidsempty stomach prior to GAcompetant administration of GA |
Clinical implications for risk of aspiration | treat all preg pts as full stomach from 8 weeks gest - 6 weeks post partum.*gastric contents more acidic (ph<2.5) and >25ml, more likely aspirated |
Roberts and Shirley recommendations | no particulate antacids use Bicitradefined risk as >25ml gastric volume and ph<2.5 |
risk factors for aspiration in pregnancy | ^gastric acid production and pepsin secretion. dec. gastric emptying(w/opioids)incompetence of lower esoph sphincter tone. anatomic displacement |
opioid related aspiration risks | Diminished gastric emptyingDiminished LES toneDiminished protective airway reflexesDiminished response to hypoxemia/hypercarbia |
Agents for aspiration prophylaxis | Ranitidine (Zantac)Metoclopromide (Reglan)Oral sodium citrate, 0.3M Bicitra |
Airway Management in the Pregnant Patient | RSI with Cricoid PressureAnatomical positioningEndotracheal intubations beyond 8-12 weeks and up to 6 weeks post partumNO nasal intubationsGastric suctioning prior to emergenceAwake extubationsDecrease size of endotracheal tubes |
Renal system changes | URETERS DILATE WK 12 - (a state of hydronephrosis may occur in 80% of women by mid-pregnancy)RBF & GFR INCREASE 50% (^renal blood flow)^Total protein & urinary albumin excretion ^ excretion of glucose^ bicarbonate excretion |
Renal implications | ^UTI, glycosuria, aldosterone ^total body water and Na levels,normal lab studies may indicate renal problems(bun/Cr should be lower) |
Significance to the Anesthetists (renal) | preeclampsia has proteinuria caused by glomerular damage.Oliguria is a consequence of arteriolar damageand spasm which may lead to acute tubular necrosis. |
HEPATIC SYSTEM | MINOR INCREASES IN SGOT & LDHBLOOD FLOW UNCHANGEDPLASMA CHOLINESTERASE LEVELS INCREASESCOLLOID ONCOTIC PRESSURES decrease COAGULATION FACTORS INCREASE |
CLINICAL IMPLICATIONS HEPATIC SYSTEM | HYPERCOAGULABILITY HEPATIC PROTEIN INCREASE BUT DILUTED IN INCREASE PLASMA VPROL0NGATION OF Sux AND chloroprocaineprogest dec.biliary motility ^chol.^risk GB disease |
CENTRAL NERVOUS SYSTEM | NEURAL SENSITIVITY TO LOCAL ANESTHETICS INCREASES, RELATED TO PROGESTERONEENGORGEMENT OF EPIDURAL VEINS, DECREASES EPIDURAL & SUBARACHNOID SPACESMAC DECREASES 25 - 40% |
Anesthetic Requirements implications of CNS in Pregnancy | Swelling of epidural veins decreases volume of CSF in vertebral column. Labor induced increases in CSF pressures. Increased neurosensitivity to local anesthetics. |
Dose of LA and Mac changes | LA dose dec. 20-30%MAC decreased 25-40% |
CLINICAL IMPLICATIONS of reduced LA and MAC | Progesterone and Beta-endorphins systems contribute to decreased anesthetic requirementsincreased risk for LA toxicity |
increase in uterine BF | non preggers 50-100cc 70Gpreggers 700cc 1100G |
UBF is directly proportional to | change in BP |
UBF is inversely proportionate to | uterine vasc. resistance |
UBF= | UAP-UVP/UVR |
Placenta increta | inside myometrium |
Placenta excreta | outside uterus |
Uterine vasculture is not autoregulated T/F | true |
If they can't stop bleeding after birth what artery do they tie off? | hypogastric |
common iliac inc. or dec. BF to the uterus | increases |
External iliac inc. or dec. BF to the uterus | decreases |
describe "steal phenomenon" | blood flow in the pelvis is preferentially redistributed toward the uterus |
When is the best time to administer an opioid to mom and avoid baby getting doped up | during a contraction |
Factors Causing Decreased Uterine Blood Flow | Uterine ContractionsHypertonusHypotensionHypertensionVasoconstriction, endogenousVasoconstriction, exogenousmost sympathomimetics(alpha-adrenergic) Exception ephedrine(beta) |
Vasopressor of choice | Ephedrine b/c it won't cause vaso constriction of uterine arteriesdue to release of NO |
ephedrine stimulates what receptors to get what outcome | Beta adrenergic for inc. CO as opposed to vasoconstriction although it has been found to decrease umbilical cord PH 7.3-7.4 |
Why would you choose not to use phenylephrine? | causes uterine artery constriction & bradycardia, but it does leave umbilical cord PH higher than ephedrine |
Regional anes effect on uterine BF | causes a sympathectomy which dec. UBF |
At what dose might propofol start to have an effect on UBF | 2mg/kg |
What effect does Thiopental have on UBF | none upto 5mg/kg |
What effect does 1.5-2 mg/kg of Ketamine have on UBF? | decreased UBF, use 1mg/kg |
inhalation agents effect on UBF | none if kept at 1 MAC or lower..>than 1 MAC dec. UBF |
hyperventilation effect on uterine BF | decreases |
Function of placenta | Produces hormones to sustain pregnancyProtects fetus from the maternal immune systemAllows for active & passive transport of nutrients & metabolites |
Size of placenta | 500g disk shaped 20cm 3cm thick |
drug placental transfer..what will cross | higher concentration, low ionization, higher lipid solubility, and lower MW.low protein binding. If it passes BBB it will pass placenta. |
Facilitated transport | carrier mediated lipid soluble molecules-more stereo specific temp regulated |
Active transport | movement of any substance accross a call membrane-a.a. proteins-sim to translocation-Na/K atpase pump |
pinocytosis | transport immunoglobulins, larger macromolecules, inc. energy to get accross |
lidocaine protein binding? | low so it passes through placenta easily..can cause ion trapping if distressed fetus |
Marcaine protein binding? | High..doesn't pass, but takes too long. |
LA of choice for fetal distress | chloroprocaine |
ion trapping | if the fetus is in metabolic acid. when the LA or opiod enters fetal circ it quickly becomes ionized in low PH and cannot cross back out. builds up->toxic |
What induction agent should you use to treat a seizure in mom | Thiopental |
Why wouldn't you use Benzos | decrease temp regulation and hypotonia of baby |
NDMR cross placenta? | No highly ionized quartenary ammonium salts |
anticholinergic of choice | Robinol does not cross..Atropine and Scop do. |
opioids cross placenta? | Yes |
Anticholinesterase cross? | limited..ionized quats |
antihypertensives/vasopressors | cross--no ACE inhibitors during pregnancy |
Mag sulfate effect on UBF | increase |
Regional anesthesia effect on UBF | reduced by causing hypotension and increased by relieving pain,dec symp activity and dec.hypervent. |
Meperidine timing for adm during labor | If delivery will be within 1 hour or 4 hours after administration..also can accumulate and cause seizures |