Anesthesia Principles and Practice I: Lecture 7 - OB Intro Flashcards

Question

Epidural Technique

Answer 1

Positioning Sitting- Easier to identify midline, more sacral spread if later in progression of labor. Lateral- If patient cannot tolerate sitting Loss of resistance (LOR) Add saline, air or mixture to connect to Touhy after you believe you are in ligamentum flavum Use either continuous or intermittent pressure to advance until plunger of syringe advances. If you unintentionally puncture the dura (wet tap) you have two choices. Thread the catheter Pull Touhy needle and attempt at different level Choice of Epidural Catheter Multi-orifice catheter (most)- thread 4-6 cm into epidural space Single orifice catheter- optimal seems 3-5 cm Threading less ↑risk of dislodging Threading more ↑risk of unilateral block, catheter knot, epidural vein insertion

Answer 2

Kit usually contains a 17-19 gauge Tuohy Needle with 1cm markings Loss of Resistant (LOR) technique Fill syringe with saline/air or mixture Attach to Touhy once engaged in interspinous ligament Advance needle with pressure on plunger LOR occurs once needle tip passes ligamentum flavum Thread catheter into epidural space Test dose with 3cc 1.5% lido 1:200,000 epi L1 is where spinal cords ends, conus medallaris... it is going after the end of the spinal cord

Answer 3

Top One: is 19g Springwound Epidural Catheter for 17G Tuohy More flexible, less MRI compatible Less likely to experience catheter migration, paresthesia, and intravascular cannulation Bottom: is 18g Perifix Catheter for 20g Touhy

Answer 4

Remove LOR Syringe and count visible markings on needle to calculate depth. Thread catheter until 20cm mark is at hub Remove needle over catheter making sure not to pull catheter out as well. Not mark on catheter at skin and withdraw to leave 4-6cm in the epidural space. Attach catheter connector and hold below insertion site to spot check no CSF (intrathecal) or blood (intravascular). Attach 3 cc Syringe and gently aspirate to confirm Test dose with 3 cc 1.5% Lido with Epi 1:200,000 Clear Occlusive Dressing ## Footnote Spinal uses 1/10th the amount of anesthetic than an Epidural

Answer 5

False LOR- can occur with loose connection between LOR syringe and needle. Can add 0.5ml air to saline in syringe and inject through needle Air bubble will compress because of resistance if in soft tissue Bubble will not compress if in epidural space Pass spinal needle through epidural needle If dural puncture occurs, likely to be in epidural space DPE or Dural Puncture Epidural technique has been associated with improved labor analgesia scores. Difficulty threading catheter Ask patient to take a breath while keeping gentle pressure, may open space at tip of Touhy Reinsertion of epidural needle at steeper angle Withdraw epidural needle and advance while applying downward pressure on hub Inject 5 cc Saline through needle into epidural space to open it Paresthesia during needle or catheter placement Stop further advancement If during needle placement, withdraw and reposition at angle away from paresthesia Common during catheter placement If it resolved continue threading catheter Blood in Epidural Needle/Catheter Remove needle and flush with saline Clotted blood can prevent LOR and increase risk of dural puncture

Answer 6

Usual test dose is 3 ml of 1.5% lidocaine with 1:200,000 epinephrine Used to diagnose subarachnoid or intravenous placement of catheter Inject between contractions ↓False positive of maternal tachycardia (d/t pain) If catheter is intravascular you would see HR ↑of 20-30 beats/minute within 30-60s Intravascular injection of toxic amount lido/chlorprocaine- usually presents as seizure Terminate seizure activity with Midazolam 1-2 mg or propofol 20-50 mg Intravascular injection of bupivacaine- Can cause rapid cardiovascular collapse/seizure activity Administer intralipid 1.5 ml/kg bolus dose

Answer 7

After no signs of intravascular/intrathecal injection Make sure patient is supine with LUD I will usually bolus 3-5cc of 0.125-0.25% Bupivacaine, or dilute the rest of the test dose (2 cc 1.5% lidocaine) in saline to a total volume of 5-6 cc. Low concentration but a bit of volume to start covering multiple dermatome levels Monitor maternal/fetal vital signs Start infusion at 8-12 cc/hr depending on stage of labor and patient height

Answer 8

5 cc bolus dose with 10-15 min lock out Max dose in 1 hr limit set at 15-30 ml (unlike in picture to the right)

Answer 9

Bupivacaine- Most common long-acting amide LA onset 15-25 minutes comes as 0.25% and 0.5% in vials 0.1% with 2 mcg/cc fentanyl common OB infusion bag Lidocaine- Short acting amide, not associated with transient neurologic symptoms with epidural admin. Onset: 5-15 minutes 2-Chlorprocaine- ester LA with short duration and rapid onset Low system toxicity- rapid plasma esterase metabolism ## Footnote Bicarb changes Pka, so it can onset quicker

Answer 10

(Duramorph)Morphine Preservative free- 2.5-4 mg in epidural at end of C-section or case. Can cause pruritus, but give up to 24 hours of pain relief Fentanyl- Bolus 50-100 mcg with LA for breakthrough pain, fetal descent, emergent C-Section Epinephrine- increases duration and may have direct action on alpha-receptors in dorsal horn Sodium Bicarbonate- increases pH of solution so its closer to pKa of LA = ↑ unionized portion of LA to enter nerve sheath = quicker onset

Answer 11

Type and screen to check for antibodies Preop fasting ASA Practice Guidelines for Obstetric Anesthesia for aspiration prophylaxis says consider: Pepcid 20 mg IV Nonparticulate antacid (30 cc bicitra) +/- Metoclopramide 10 mg Good IV access- 2 PIV for repeat C-Section or history of postpartum hemorrhage. Standard monitors Ancef 2 Gram, >120 kg 3 g IV Azithromycin 500 mg if rupture of membranes >12 hrs Antibiotics in 30-60 min before incision is optimal Meds need to be given 30-40 minutes to be maximally effective. Bicitra works immediately and should be especially considered for emergent cesarean when NPO status is not adequate. Azithromycin associated with 50% reduction in outcome of endometritis, wound infection in high risk patients.

Answer 12

Quickest onset 3% 2-chlorprocaine (anecdoctyl that might not make other meds work as well) 2% Lidocaine with bicarb 2% lidocaine 0.75% Ropivacaine 0.5% Bupivacaine Adding fentanyl can speed onset How to dose 10-20 cc of 2% lidocaine total needed for adequate surgical level anesthesia. Try to get a T4 block level to cover Visceral (Peritoneal) manipulation Onset around 5-10 minutes Bicarbonated chlorprocaine was not analyzed in this data set, but I normally give 2% lido with bicarb

Answer 13

Fentanyl- 50-100mcg Morphine (Duramorph®) 1-3 mg Gives post-op pain relief or 18-24 hours Epinephrine Increases density of block, reduces systemic absorption, prolongs. Duration of action Sodium bicarbonate Faster onset (for lido/chloroprocaine) Small volume (<1 cc)

Answer 14

If no epidural, and time to place anesthetic (baby’s heart rate is not down) My usual cocktail 1.6 cc 0.75% Bupivacaine with Dextrose (12 mg) 15 mcg Fentanyl (0.3 cc in 1 cc syringe) 150 mcg Duramorph ® (0.15 cc of 1 mg/ml Duramorph®) Consider preop Zofran to decrease pruritus Phenylephrine infusion after placement (0.2 mcg/kg/min) to reduce N/V Fentanyl in spinal helps with hypotension Vomiting and Nausea is extremely Common Consider CSE for longer C-Sections Repeat, Academic Center, Etc

Answer 15

Pros More reliably dense block Easy to perform Smaller gauge needle (PDPH<1%) Cons Hypotension can be rapid and significant

Answer 16

Epidural Already in place Incremental dosing leads to less sympathectomy Epidural Catheter can migrate intravascular or intrathecal Higher rate of PDPH Less dense Block Spinal Take time to place One shot Hypotension

Answer 17

Extreme fetal distress (in absence of epidural catheter) Significant Coagulopathy Inadequate regional anesthesia, without time to replace Acute maternal hypovolemia/hemorrhage Patient refusal of regional anesthesia

Answer 18

Ondansetron 4 mg preop Consider Scopolamine patch w previous hx of N/V Dexamethasone 4-8 mg Mostly related to hypotension Start Phenylephrine infusion after placement of spinal or PRN Ephedrine also effective Visceral manipulation 25-50 mcg Fentanyl may help

Answer 19

Pre-eclampsia New onset of hypertension and proteinuria OR new onset hypertension and end-organ dysfunction Systolic BP >140 systolic and/or Diastolic >90 mmHg at lest two times after 20 weeks and at least of of the following Serum Creatinine >1.1 Pulmonary edema Visual Symptoms- Blurred vision, sparks, flashing lights New Onset Headache Proteinuria- >.3 g in 24 hr urine specimen Platelets <100,000/microL ## Footnote Moms go on Magnesium because it is neuroprotective to both mom and baby

Answer 20

Eclampsia All the previous symptoms but with grand mal seizures Prescient indicators HTN (75%) Persistent frontal or occipital headaches or thunderclap headache (66%) Visual disturbances (27%) RUQ or epigastric pain (25%) Asymptomatic (25%)

Answer 21

Version of pre-eclampsia where hemolysis, elevated liver enzymes, and thrombocytopenia predominate. Most anesthesiologists want to see >80,000 platelets to place epidural... same with removal Many present with tender epigastrium, RUQ pain, or below sternum Hemolysis indicated by bilirubin >1.2 mg/dL Severe anemia w/o blood loss Labs may worsen for up to 48 hours after birth Do not remove epidural catheter until platelet level has stabilized

Answer 22

Rare and Catastrophic Cytokine storm Sudden CV collapse, Respiratory failure and hypoxia +/- seizures, may progress to DIC Occurs during labor or within 30 min of delivery of placenta Signs and Symptoms 90% presentation is abrupt and catastrophic Aura of sudden doom, chills, nausea, agitation, anxiety, or change in mental status Oxygen desat, dyspnea, tachypnea, cyanosis, crackles If patient survives initial event- non cardiogenic pulmonary edema is present AOK Treatment Atropine 0.2 mg to block vagal reflex and resulting hypotension, reverses pulmonary artery spasm. Ondansetron 8mg blockade of serotonin receptors reverses pulmonary vasoconstriction and platelet activation Ketorolac 15-30 mg is a potent thromboxane blocker, which helps prevent activation of coagulation cascade and inflammatory mediator release One of the biggest risk factors for AFE is placenta previa Second leading cause of maternal mortality in the US

Answer 23

Postpartum hemorrhage prophylaxis Tranexamic acid 1 g Either before skin incision or after cord clamp Oxytocin (Pitocin) Infusion Normal bag is 30 units in 500 ml Slow bolus of 3-5 units after delivery of baby may help prevent atony in high-risk patients Rapid transfusion may cause hypotension or even CV collapse Hemorhage and CV conditions are the leading causes of maternal death in the US Most Common Causes of PPH Tone- Uterine Atony Trauma- Laceration/Rupture Tissue- Retained tissue, blood clots, placenta accreta spectrum Thrombin- Coagulopathy ## Footnote Quick infusion of Pitocin can cause nausea

Answer 24

Medical Treatment of persistent uterine atony Methylergonovine (Methergine®) 0.2 mg IM or directly into myometrium Never inject IV Contraindications include hypertension, CAD, CVD, Raynaud’s Can repeat q 2-4 hours Carboprost tromethamine (Hemabate®) 0.25 mg IM Can repeat q 15-90 minutes, switch to different uterotonic if no response to 1-2 doses Contraindication Asthma Misoprostol 400-800 mcg (2-4 tablets) sublingual/buccal (MAKES MOM SHAKE MORE THAN NORMAL???) Risk factors for atony Prior PPH and Prolonged Labor are biggest risk factors Chorioamnionitis- Patients risk for chorio increases the longer their membranes are ruptured Use of Magnesium Sulfate Labor Induction of Augmentation Fibroids Uterine Overdistention from Multiple Gestation Macrosomia- large baby Polyhydramnios- lots of amniotic fluid If medications fail and atony is present during Cesarean, the surgeon may ligate the uterine arteries and or oversew the uterus to compress it. Uterine Artery Embolization in Interventional Radiology may be considered if these measures fail or if atony occurs after vaginal birth. Hysterectomy is the last resort but the definitive intervention when bleeding cannot be controlled by any other means.

Answer 25

Causes Vaginal or Cervical lacerations May need to bolus epidural/give sedation for repair Partial or complete myometrial rupture Risk Factors Vaginal Delivery Instrument assisted vaginal birth Episiotomy Persistent Occiput Posterior (OP, or sunny side up) Cesarean Delivery after full dilation, as uterine incision may be extended Either baby doesn’t drop down or babies heart rate necessitates Cesarean

Answer 26

Placenta Accreta Spectrum: Placenta Accreta - Placental villi attach to uterine myometrium. Placenta Increta- Placental villi invade myometrium Placenta Percreta- Placental villi go through myometrium into serosa or adjacent organs

Answer 27

Placenta Previa Painless vaginal bleeding is the hallmark An indication for Cesarean Major Risk Factors Previous placenta previa Previous Cesarean Delivery Multiple Gestation (40% higher in twins)

Answer 28

Acute Placental Abruption: A significant cause of maternal morbidity and neonatal M&M Placenta separates from the decidua too soon. Symptoms: Non-reassuring FHT, Severe vaginal bleeding, abdominal pain Risk Factors: Previous abruption, hypertension, structural uterine abnormalities, cocaine use, cigarette smoking. ## Footnote Bleeding and hurts vs Placenta Previa where Bleeding, but doesnt hurt

Answer 29

Retained Placenta after Vaginal Birth Risk Factors: Maternal age >30, pre-eclampsia, stillbirth, small for gestational age neonate, Pre-term gestational age Treatment: May require dilatation and curettage procedure in operating room to remove products of conception.

Answer 30

Consumption or hemodilution of clotting factors during PPH, low platelets Thrombin acts on fibrinogen leads to fibrin forming a clot (of all the clotting factors, need fibrinogen the most) Excessive thrombin can lead to DIC

Anesthesia Principles and Practice I: Lecture 7 - OB Intro Flashcards

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