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OB Anesthesia. Denise Weiss DO Anesthesiologist. Goals of obstetrics. Healthy mom/baby = happy and healthy doctors and nurses, family. OB Anesthesia. NPO guidelines Solid food (fatty foods) = 8hrs Light meal (toast, crackers, etc) = 6 hours Clear liquids =2 hours Breast milk = 4 hours
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OB Anesthesia Denise Weiss DO Anesthesiologist
Goals of obstetrics Healthy mom/baby = happy and healthy doctors and nurses, family
OB Anesthesia • NPO guidelines • Solid food (fatty foods) = 8hrs • Light meal (toast, crackers, etc) = 6 hours • Clear liquids =2 hours • Breast milk = 4 hours • On L/D clear liquids ok during labor, (often only ice chips allowed) • Stricter adherence to ice chips if higher risk of operative delivery • Scheduled inductions should be instructed to be NPO • All pregnant pts are considered to have full stomachs but the goal is to minimize risk if need for intubation occurs
OB Anesthesia • Reasons for NPO guidelines: • Higher risk of aspiration in pregnant patients (1 in 661 vs 1 in 2131 gen pop) • Increased intragastric pressure due to large uterus • LES is pushed up and to the left (sim to hiatal hernia) • Decreased LES tone secondary to progesterone • High incidence of GERD • Gastric pH is more acidic • Active phase of labor slows gastric emptying
OB Anesthesia • Higher risk of difficulty in airway management • Morbidity/mortality in pregnant pts have been attributed often to failed or difficulty managing the airway • Airway is more friable and edematous in pregnant pts • Increased breast size can make laryngoscopy very difficult • Decreased FRC so desaturate quickly
OB Anesthesia • pH less than 2.5 and gastric volume greater than 25ml are identified risk factors for aspiration • Pregnant pts going to CS either emergently or scheduled receive pharmacologic prophylaxis (we use reglan and alka selzer gold, bicitra increases pH without altering volume)
OB Anesthesia • Difficult airway • Incidence of failed intubation in obstetric pts @1:300 • 1:2330 in general OR population • Airway complications are the leading cause of anesthesia mortality • Single largest class of injury related claims from the ASA Closed Claims database involves respiratory events
OB Anesthesia • Basic Needs for the OR • Monitors • ECG,NIBP,SPO2, FHR monitor, suction • Equipment for difficult airway, and emergency drugs • Checked daily
OB Anesthesia for C-Section • Spinal • Epidural • Combined Spinal/epidural • General • Local
Contraindications for Neuraxial Techniques • Pt refusal or inability to cooperate • Increased ICP secondary to mass lesion • Skin or soft tissue infection at site of needle placement • Coagulopathy • Uncorrected maternal hypovolemia • Low platelets (depends)
Complications with Neuraxial Techniques • Infection • Postdural Puncture Headache • Incomplete or failed block • Neurologic injury(incidence is 20 in 1.2million for subarachnoid blocks, 20 in 450,000 for epidurals) • Meningitis or arachnoiditis • Spinal hematoma(sharp back and leg pain-numbness and motor dysfunction(loss of bowel/bladder fxn) • Emergent MRI or CT and referral (6-12 hr window for decompression)
General Anesthesia • Maternal refusal or inability to cooperate with neuraxial tech • Presence of contraindication to neuraxial tech • Insufficient time to induce neuraxial tech(cord prolapse with persistent bradycardia) • Failure of neuraxial technique • Fetal issues (EXIT procedure)
Local Anesthesia • Very rarely used • Dire emergencies when anesthesiologist/CRNA not available • Success dep on avoiding use of retractors, and not exteriorizing the uterus. • After delivery of baby, obtain hemostasis until arrival of anesthesia personnel
Local Anesthesia • 0.5% lidocaine with epi • 25g spinal needle to create skin wheal just below umbilicus directed toward symphysis pubis. SQ injection along this full area. • Ideally wait 3-4 min to take effect • Vertical incision to rectus then local into rectus fascia and muscles. Takes 4-5min for anesthesia to be complete
Local Anesthesia • Parietal peritoneum infiltration and incision • Visceral peritoneum infiltration and incision • Paracervical injection • Uterine incision and delivery • Obtain hemostasis • Await availability of general anesthesia
Local Anesthesia • Disadvantages • Pt discomfort • Risk for local anesthetic toxicity (may use up to 100ml of local • Difficult operating conditions to say the least
Maximum Local Anesthetic Dosages • Easy formula for bupivicaine (for 0.25% can give 1cc/kg, for 0.5% can give 1/2cc per kg. Lidocaine 4cc/kg plain, 7cc/kg with epi (for obese pts keep in mind max dose)
PCA Fentanyl • Great alternative for pts who cannot have an epidural • All opioids cross placenta by diffusion secondary to lipid solubility • All are associated with neonatal depression • Fentanyl readily crosses placenta but avg umbilical to maternal conc ratio is low at 0.31 • Studies show reduced FHR variability but difference in APGAR scores, respiratory depression and Neurologic and Adaptive Capacity scores at 2-4 hrs or 24 hrs compared to infants whose mothers did not have fentanyl(Am Journal of Obst/Gyn; Anesth/Analgesia)
PCA Fentanyl • Rapid onset • High potency • Short duration • No active metabolites • One of most commonly used for PCA
PCA Fentanyl • Must have resuscitation equip available • Pulse oximetry, +/- etCO2 monitoring • One/one nursing • Education of family members • Loading dose (50-150mcg • Bolus 25-50mcg(start at 25, and assess) • Lockout 10min • No basal rate
PCA Fentanyl • As labor progresses may need to decrease lockout time to 5min
OB in Rural Areas • Likely will not have immediately available anesthesia provider • OB nurses can assist with management of epidural infusions • ASA has a consultation program that will help with setting up the anesthesia service to fit the needs of the facility • Consensus of all involved that OB anesthesia is a priority and a worthwhile goal
OB in Rural Areas • Anesthesia provider does NOT have to stay in house during course of epidural infusion • ASA recommends it but recognizes difficulty