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OB 5
Princinples II OB COMPLICATIONS
Question | Answer |
---|---|
COMPLICATIONS IN OB ANESTHESIA. HOW MANY MATERNAL DEATHS IN US B/W 1987-1990 | 2.5% OF ANESTHESIA DEATH |
WHAT HAPPEN IN 1991-2002 WITH MATERNAL DEATH RELATED TO ANESHTESIA | IT DECR TO 1.6% (APPROX. A 59%)[NIH] -Most related to GA for C/S Modest decr each year - Attributed to inc knowledge and use of RA techniques Maternal death rate among African American women remains signifi higher than that among Caucasian women 6-7X M |
WHAT IN OB CAN BE RELATED TO HYPOTENSION. | IN OB, NEARLY ALL NAUSEA AND/OR VOMITING CAN BE RELATED TO HYPOTENSION. |
NAUSEA AND VOMITING CAN ALSO HAPPEN BECAUSE OF? | -SYMPATHETIC BLOCK WHICH MAY ALLOW UNOPPOSED GI PARASYMPATHETIC/VAGAL STIMULATION. -SPINAL OPIOIDS -BRAIN STEM HYPOXIA-CHEMORECEPTOR TRIGGER ZONE (CEREBRAL ISCHEMIA). |
SCOPOLAMINE PATCH (POST-C/S) IS HELPFUL WITH? | -IN PLASMA WITHIN 4 HOURS, LASTS AT LEAST 24 HOURS -SIDE EFFECTS: DRY MOUTH, CONSTIPATION, DROWSINESS, DILATED PUPILS. |
WHAT DOES CTZ-CHEMO TRIGGER ZONE DO? | CTZ-CHEMO TRIGGER ZONE (SYSTEMIC HYPOTENSION PRODUCES CEREBRAL ISCHEMIA CAUSING NAUSEA) |
CHEMORECEPTOR TRIGGER ZONE IS FOUND IN? | THE MEDULLAR |
WHAT ARE THE NEUROTRANSMITTERS INVOLVED? | Acetylcholine Dopamine Histamine (H2) Substance P Serotonin 5 HT3 Opioid |
RISK WITH EPIDURAL PLACEMNT | POST-DURAL PUCTURE HEADACHE |
POST DURAL PUNCTURE HEADACHE | Postural in nature (↑ sitting or standing) Photophobia Frontal-occipital in nature (dull, throbbing) Diploplia (double vision, d/t stretch of CN VI) May not have immediate onset (12-48 hours after) |
PDPH TREATMENT with epidural blood patch. | Epidural Blood Patch (immediate relief) Usually at same level or one beneath 15-20mL of patient’s blood is target volume to inject Lie quietly supine for 1 hour post procedure Success rate over 95%; may need repeat x1 Strict aseptic technique. |
COMPLICATION OF PDPH CONT. | -Loss of CSF through the hole in the dura -Total CSF = 150mL -Produced/reabsorbed qd = 500mL -Significant loss secondary to needle size -Rates vary with institution and experience |
WHAT HAPPEN WHEN NEEDLE ACCIDENTALLY PUNCTURE THE DURA? | SPINAL FLUID LEAKS |
WHAT SIZE NEEDLE DOES SAB USE? AND EPIDURAL | S & M pp.260-1; SAB use small gauge needle (24-25 g and “pencil-point” needle tip); Tuohy- 16-18g for Epidural |
Treatment for PDPH | Caffeine (500 mg in l - Liter NS IV over 1 hour), bed rest IV hydration, analgesics With placement of blood patch. the blood draw and epidural has to be a strict asceptic technique to prevent infection. |
intravascular injection of local anesthetic | CNS and/or CV consequences Numbness or tingling around the mouth Strange metallic taste in mouth Ringing in the ears |
what is the importance of a test dose, if you injected LA intravascularly. | Importance of test dose (watch for HR increase 30 bpm in 30 secs) Total preparation for the worst (seizures, CV collapse) Cardiovascular support is vital |
what is epidural test dose? | Epidural test dose-3 mL 0f 1.5% lidocaine with 1:200,000 epinephrine; if test dose given in subarachnoid space, spinal block occurs in 3-5 min; if test dose injected into IV, HR increase in 45 seconds (HR increases 30 bpm) Duke p. 321 |
Accidental subarachnoid injection | -Usually discovered with test dose (3-5 minutes) -May have signs and symptoms of “total spinal” Hypotension -Incidence is much lower if bolus doses are kept to 3-5mL |
Subdural catheter insertion | -It is possible to place the epidural catheter in the subdural space -Test dose often negative -Delayed onset of significant spread of local anesthesia – may take 10-25 minutes to unfold -Emergency CV and ventilatory support |
comblication in OB anesthesia premature labor. | Leading cause of perinatal morbidity 10-12% of all deliveries Tocolysis (anti-contraction, labor repressant) Beta receptor agonists (Terbutaline, ritodrine) MagSO4 (Ca++ antagonist) CCB,(Procardia, Nifedipine) Prostaglandine syn.inh.(indo, NSAID |
Tocolysis (anti-contraction, labor repressant) | Beta receptor agonists (Terbutaline, ritodrine) Magnesium sulfate (Ca++ antagonist) Calcium channel blockers (Procardia, Nifedipine) Prostaglandin synthesis inhibitors (ASA, NSAIDS, Indomethacin) Oxytocin Antagonists |
Magnesium Sulfate | Still used for tocolysis and PIHD (Pregnancy Induced HTN disorder) Causes relaxation of vascular, bronchial, and uterine smooth muscle Alters calcium transport and availability Hyperpolarizes the plasma membrane and inhibits myosin activity |
What is the normal serum magnesium level? | Normal serum magnesium is 1.8-3mg/dL Therapeutic serum magnesium is 4-8 mg/dL |
Side effect of Magnesium sulfate? | Deep Tendon Reflexes lost at 10 mEq/L; SA/AV block & respiratory paralysis lost at 15 mEq/L; cardiac arrest occurs at 25 mEq/L (Duke p.328) |
Preeclampsia (PIH) | 2-6% of parturients Higher in primigravidas under 20 years of age or older than 35 years of age Exact cause is unknown Abnormality in the ratio of thromboxanes (vasoconstrictor) to prostacyclins (vasodilator); (imbalance) |
Signs and symptoms of PIH | Hypertension, edema, and proteinuria Diagnosis is sustained B/P > 140/90 2+ or > 300 mg/24 hr. proteinuria Pretibial edema |
What is PIH | Pregnancy induced hypertension |
PAH | Pregnancy associated hypertension |
Mg.sulfate side effects | Muscle weakness, loss of deep tendon reflexes Headache, dizziness, nausea Respiratory depression, ECG changes, flushing Think of it as a partial neuromuscular blockade Rapidly removed from the body, can be antagonized with calcium chloride |
Preeclampsia | Can be mild to severe Severity of hypertension parallels the severity of the disease Maternal mortality Cerebral hemorrhage, pulmonary edema, renal failure, seizures (secondary to cerebral edema) |
what will cure the disorder of preeclampsia | Delivery of the fetus will cure the disorder May want Betamethasone for lung maturity (baby) |
Pathophysiology of preeclampsia | Incr capill permeability Thromboxane A2 is a potent vasoc and platelet aggregator. HTN results in ↓ intravascular vol. Compensatory response to loss of protein and fluids via the kidneys decr. placental perfusion: IUGR, plancenta infaction fetal hypox |
what does hypertension do in Preeclampcia patho. | Hypertension causes capillary injury, which in turn stimulates platelet aggregation (thrombocytopenia & DIC)[N&P p. 1136) |
Preeclampsia patho | Endothelial dysfunction Hypercoagulable state leads to end organ injury Increased vascular sensitivity to catecholamines Catecholamine levels are increased, which affects uterine blood flow Arteriolar constriction increases left ventricular workload |
Magnesium is used universally to control PIH because it ? | Reduces the likelihood of eclampsia by 58% Decreases maternal mortality by 45% Treatment goals -Prevent eclampsia (preeclampsia + seizures) -Avoid decreasing uterine blood flow -Maximize organ perfusion |
Magnesium may also aid in decreasing? | Fibrin deposition, which is a factor in HELLP syndrome. |
Regional anesthesia is preferred because? | Carefully initiated epidural can decrease blood pressure and diminish stress response of labor Slow and deliberate dosing – knowing that their contracted intravascular volume status may cause precipitous drops in blood pressure |
What is HELLP syndrome? | hemolytic anemia, elevated liver enzymes, low platelets (severe form of preeclampsia) Duke p. 327 |
Regional anesthesia and preeclampsia | Avoids stimulation or manipulation of an edematous airway Careful consideration of coagulation studies Bleeding time and platelet count. Epidural may in fact increase placental perfusion. Maintain SBP of 90 mmHg or greater at all times. |
With RA. patient may received their what prior to initiation of labor analgesia | antihypertensive agent. and be careful. |
Caution with your normal fluid volume preload – may already have a strained LV and you could end up with what? | Pulmonary edema |
what do you want to monitor with preeclampsia patient having regional anesthesia? | Occasionally placement of CVP to monitor fluid volume load is necessary Platelet counts can decrease precipitously – you should have a recent one to base your decision on |
What is the standard medication used for epidural? | Bupivicaine is the standard in epidural due to slower onset |
Why bupivicaine? | Bupivicaine has slower onset than lidocaine or chlorprocaine, allowing the CRNA to react to changes in B/P |
Why don't you wnat the sysmpathectomy to wear off abruptly? | Because Increased intravascular fluid volume to compensate for sympathectomy may lead to hypertensive crisis when normal vascular tone returns |
Preeclampsia with general anethesia. | May be necessary secondary to coagulopathy or rapid demise in maternal or fetal condition Maternal brain is edematous and more sensitive to IV anesthetic agents |
The preeclampsia patient may have? | Exaggerated response to laryngoscopy Upper airway swelling Control of B/P during induction is vital to prevent intracranial hemorrhage Be ready for difficult airway!! |
Antihypertensive to control blood pressure. Labetolol | α1 selective and ß nonselective blocking agent Maintains uteroplacental perfusion Minimal neonatal side effects at doses up to 1mg/kg in mother |
Hydralazine | Does not interfere with perfusion as long as B/P systolic >90 Potent pulmonary artery dilator Slow onset precludes use in emergent situations |
Nitroglycerin | Quick onset but unpredictable (quick half-life) Questionable increase in ICP in severely preeclamptic parturients |
Esmolol | Held great promise, but is actually found to be a bad idea Crosses the placental and causes a clinically significant fetal β blockade |
Muscle relaxants | All NMB agents are significantly potentiated by mag. infusions Half of the ED95 of a normal dose caused 100% blockade lasting upwards of 35 minutes in a preeclamptic mother on Magnesium as opposed to an average 42% blockade for 9 minutes in a normal pt. |
HELLP Syndrome | Hemolysis Elevated Liver enzymes Low platelet count |
Symptoms of HELLP | Epigastric pain, upper abdominal tenderness, proteinuria, jaundice, compensated DIC By far the sickest patients you will ever see in OB Cure is delivery of fetus Have to put mother’s health first!! |