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Preparing for OB
Anesthesia Emergencies Brandon Durbin, CRNA & Kristin Salyards, MSN, RNC-OB
Gibson Area Hospital & Health Services
Scenario Marie is a 26 year old primigravida with a birth plan that is on file with her
prenatal records. She was admitted 12 hours ago for PPROM. She is 5’6’’ and weighs 165 lbs. Marie has NKDA. She is A+ blood type, HIV negative, Rubella immune, and GBS negative.
Marie wanted to wait for labor to start naturally and avoid Pitocin if at all possible. 4 hours ago when Marie was still not contracting on her own, she was started on Pitocin. She is now 7cm and is requesting an epidural. Her fluid bolus is infusing. Labs are: Hgb 10.8, Hct 32.4, Plt 235,000, WBC 12.3. Vital Signs are: BP 112/69, HR 74, RR 16, T 36.5 C
The CRNA is present discussing the epidural procedure and obtaining informed consent. The patient is prepped and the procedure is started. The test dose is given without incident. The bolus is administered and the infusion is started.
4 minutes later the FHR becomes a category II tracing. Marie begins to complain of ringing in her ears and states her tongue feels numb. Marie becomes bradycardic, hypotensive, and having difficulty breathing.
The CRNA at the bedside. A code blue is initiated and the CRNA requests lipids & tubing be brought to the room.
Objectives & Disclosures
Define Malignant Hyperthermia (MH) and Local Anesthetic Systemic Toxicity
(LAST)
Identify signs and symptoms of MH and LAST
Understand the physiological changes associated with MH and LAST
Discuss treatment and prevention of MH and LAST
Review REAP criteria regarding anesthesia emergencies in OB
Discuss implementation strategies for meeting REAP criteria regarding
anesthesia emergencies in OB
Neither Brandon Durbin or Kristin Salyards have any financial interests or
relationships to disclose.
Gibson Area Hospital
Overview of Gibson Area Hospital &
Health Services (GAH) GAH is an independent, non-profit, critical access hospital in rural east
central Illinois.
GAH offers obstetric, emergency, general medical, intensive care, general
surgery, orthopedic surgery (including spine), dental, cardiology, plastic
surgery, and behavioral wellness services as well as a variety of outpatient
and visiting specialty services.
GAH has clinic locations in 12 surrounding communities.
GAH has Accreditation thru DNV GL- Healthcare.
GAHHS employs over 800 people throughout the healthcare system.
GAH Obstetrics Department
GAH is a Level I OB Facility affiliated with the South Central Illinois Perinatal
Network thru HSHS St. John’s Hospital in Springfield, Illinois.
GAH averages approximately 225 deliveries per year.
GAH has earned the Women’s Choice Award in Obstetrics every year since
2015.
GAH opened a new unit comprised of 5 LDRP suites, 1 triage room, and a
cesarean section suite in November of 2014.
Surgery Department staff members scrub, circulate and recover cesarean
section patients.
OB staff are present during the case and perform all newborn care
Anesthesia services are available 24/7.
Get to know Brandon Durbin
BSN from St. John’s College, Department of Nursing, Springfield, IL (2007)
ICU Staff Nurse at Decatur Memorial Hospital
MSN, CRNA from Southern Illinois University, Edwardsville, IL (2011)
Anesthesia experience includes: general surgery, orthopedic surgery, ENT,
pediatrics, OB/GYN, CVOR
Get to know Kristin Salyards
B.S. in Business Administration & Accounting from Eureka College, Eureka, IL
B.S.N. from Lakeview College of Nursing, Danville, Illinois,
M.S.N. with a specialization in Health Systems Leadership from Gonzaga
University, Spokane, Washington
Nursing experience includes L&D, Mother/Baby, Newborn Nursery, and Level
III NICU
Management Experience includes House Supervision, Director of the Sleep
Lab, Director of WIC and FCM Services, Director of OB
Anesthesia Emergencies
in OB Prepared by:
Brandon Durbin, MSN, CRNA
Carolina Mette, MSN, CRNA
Shawna Waterstradt, MSN, CRNA
Gibson Area Hospital and Health Services, Gibson City, IL
Malignant Hyperthermia
(MH)
Malignant Hyperthermia
“Malignant hyperthermia (MH) is a biochemical reaction
response triggered by commonly used general anesthetics
and the paralyzing agent succinylcholine, within the
skeletal muscles of susceptible individuals.” – MHAUS
Malignant hyperthermia is a RARE BUT DEADLY
hypermetabolic event. Complications include cardiac
arrest, brain damage, internal bleeding, organ system
failure, or death, due to cardiovascular collapse.
Epidemiology
Reported frequency of MH is 1/5,000 to 1/100,000 anesthetics
Reported from every country and ethnic group
Based on reports from MHAUS, there are about 600 cases of MH per
year in the United States
“Hotspots” – Wisconsin, Michigan, West Virginia
Pathophysiology
Patients susceptible to MH have a defective calcium channel on the
sarcoplasmic reticulum of the skeletal muscle cells
Certain medications (referred to as triggers) induce the massive release of
stored calcium ions within the muscle cells
Calcium release causes the muscle fibers to contract
Excessive muscle contractions cause excessive heat (hyperthermia) and
results in metabolic acidosis
Pathophysiology (continued)
During fulminant MH episode, the following occur:
Rapid ATP consumption
Cellular acid content increases
Cell membranes break down
Muscle breakdown begins (rhabdomyolysis)
Cardiac changes
Tachycardia and dysrhythmias
Hypotension
Decreased cardiac output
Cardiac arrest
Triggering agents for MH
Volatile inhalation anesthetic agents
Sevoflurane, Isoflurane, Desflurane
Succinylcholine – depolarizing muscle relaxant
Non-Triggering Agents
Opioids
Non-depolarizing muscle relaxants
Nitrous oxide
Ketamine
Propofol
Benzodiazepines
Local anesthetics
Epidurals and Spinals
Susceptibility
MH is acquired through an autosomal dominant inheritance pattern linked to
as many as 80 genetic defects
Carriers with susceptibility are often unaware they are at risk
Children and young adults are at greater risk
As many as 5%, do not survive an MH event
Susceptible patients with no previous MH event during general anesthesia can
still have an MH crisis during subsequent exposure to triggering agen
Susceptibility (continued)
Several muscular disorders have been associated with MH susceptibility. These
are generally very uncommon conditions. Patients with the following conditions
need to be treated as being MH susceptible:
Central Core Disease (CCD) and Multiminicore Disease (MmD)
Duchenne’s Muscular Dystrophy
Becker’s Muscular Dystrophy
Myotonias
Mortality
January 2006 – 2008, the MH Hotline received
503 calls from hospitals. 28 cases of MH, 2 patient deaths (7% mortality)
44 calls from ambulatory settings. 13 cases of MH, 3 patient deaths (21%
mortality)
A fulminant MH episode occurring outside of the hospital setting is more likely to
lead to a bad outcome as compared to one occurring in a hospital setting.
Testing for MH Susceptibility
Muscle contracture test: Caffeine Halothane Contracture Test
Gold standard
Most sensitive, specific test for diagnosis of MH
Requires skeletal muscle biopsy from patient’s thigh to assess muscle contractile
properties upon exposure to ryanodine receptor agonists.
Must be performed at a MH Muscle Biopsy Center
California, Maryland, North Carolina, Minnesota, Ontario
Genetic testing – Ryanodine Receptor (RYR1) gene sequencing
Less invasive
Preoperative Questioning
During the preoperative nursing or anesthesia assessment, questions regarding the patient’s past surgery and anesthesia history can help identify at risk patients:
Have you ever had a “bad” reaction to anesthesia?
Have you or a family member had a problem with anesthesia?
Have you or a family member had a fever while under anesthesia?
Has a family member died unexpectedly in the OR?
Have you or anyone in your family experience a heat stroke that resulted in hospitalization?
Have you every noticed dark urine after general anesthesia or heat-related illness?
Do you or anyone in your family have a neuromuscular disorder?
Report any concerns to your anesthesia provider.
Planning in At risk patients
Susceptible patients can still have surgery and anesthesia.
Involve your anesthesia provider early if you have any concerns.
MH can be avoided by eliminating trigger agents from the anesthetic plan.
Prevention of a MH event is the best treatment.
Formulate a plan involving the patient, nursing staff, anesthesia staff and
OB/GYN.
MH drills in your Labor and Delivery Unit or Main Operating Room can help
prepare staff for an MH event.
Day of surgery
Previously uncomplicated anesthetics does not eliminate the risk for MH in a
susceptible patient.
If possible, schedule surgery as the first case of the day.
Avoid triggering agents (anesthesia).
Have MH cart and Dantrolene readily available.
Closely monitor for early signs of MH.
MH can occur as late as one hour after exposure to triggering agents. Patients
should be monitored in PACU for at least one hour.
Signs and Symptoms
Elevated ETCO2 or tachypnea
Elevated temperature. (Can increase 1.8 degrees Fahrenheit every 3 min)
Labile blood pressure
Tachycardia or arrhythmias – LV Failure – Pulmonary Edema - Cardiac Arrest
Masseter spasm (occurs in 20-30% of MH cases)
Generalized muscle stiffness or rigidity
Acidosis
Electrolyte changes (K+ and Ca++)
Treatment
1. Notify the surgeon to halt the procedure. Discontinue volatile agents and
succinylcholine.
If the surgery must continue, maintain general anesthesia with non-triggering
agents.
2. Get dantrolene and MH cart.
3. Hyperventilate with 100% oxygen. If available, insert activated charcoal
filters on the breathing circuit.
4. Dantrolene administration
5. Call for help within your organization. Call the MHAUS hotline
Treatment
Obtain Labs
ABG, CMP, Myoglobin (urine and serum), PT, PTT, INR, FDPs, Liver Enzymes, lactate
Cool patient if core temperature is above 39 degrees Celsius. Stop cooling when temperature has decreased to 38 degrees Celsius.
Treat hyperkalemia with calcium chloride, sodium bicarbonate, or glucose/insulin
Monitoring
Core temperature
Urine output with foley
A-Line / CVP if needed
Transfer to PACU then ICU for 24 hours
Dantrolene (Dantrium)
Acts as a skeletal muscle relaxant by depressing excitation-contraction
coupling in skeletal muscle by binding to the ryanodine receptor 1, and
decreasing intracellular calcium concentration.
Initial dose is 2.5 mg/kg IV Push, repeat PRN
2-4 people dedicated to mix Dantrolene!!!
Mix each 20 mg vial with 60ml of PF sterile water (use spikes)
Shake until clear – 2.5-4 min per vial
Know where additional Dantrolene is stored because average use per MH
event is 30 vials.
Aftercare
Give dantrolene 1 mg/kg every 4-6 hours for 24-48 hours
Monitor for recrudescence – rate is 25%
Monitor VS – HR, BP, O2, ETCO2 (if intubated), temperature
Continue to monitor labs results, assess need for repeat testing.
Monitor for signs of myoglobinuria and rhabdomyolysis and institute therapy
to prevent renal failure.
MH CART
Dantrolene / Ryanodex
Sterile Water, Preservative-free
Sodium Bicarbonate
Dextrose
Calcium Chloride
Regular Insulin
Lidocaine, Amiodarone
Refrigerated cold saline for IV
administration
Foley
Charcoal filters
Syringes (60ml and 5ml)
IV supplies, IVF tubing
Pressure bag
Disposable cold packs
Core temperature probe
NG Tube
?Aline/CVP supplies
Ice bags and bucket for ice
Local Anesthetic System Toxicity
(LAST)
Local Anesthetics
Aminoamides (Amides)
Lidocaine
Mepivacaine
Prilocaine
Ropivacaine
Bupivacaine
Articaine
Metabolized by the liver
Allergy is common
Longer acting
Aminoesters (Esthers)
Procaine
Chloroprocaine
Cocaine
Tetracaine
Benzocaine
Metabolized by plasma and tissue
cholinesterase
Higher allergy potential d/t PABA
(p-aminobenzoic acid)
Shorter acting, except tetracaine
Absorption rate
IV
Tracheal
Intercostal
Caudal
Paracervical
Epidural
Brachial Plexus
Sciatic
Subcutaneous
LAST
Local anesthetic systemic toxicity is a serious but rare consequence of
regional anesthesia. It most commonly results from an inadvertent vascular
injection or absorption of large amounts of the LA from certain nerve blocks
requiring large volume injections.
Nagelhout & Plaus, 2014, p.134
Time of Onset
50%
25%
10%
15%
<1min
1-5 min
5-10 min
>10 min
Monitor the patient during and after injection as clinical toxicity can be delayed
up to 30 min or longer for tumescent anesthesia
Systemic effects
Therapeutic doses of lidocaine
Lightheadedness, tinnitus,
circumoral and tongue numbness
Toxic doses of lidocaine
Visual disturbances
Muscular twitching
Convulsions
Unconsciousness
Coma
Respiratory arrest
CVS depression
Bupivacaine and Ropivacaine are
cardiotoxic
LAST does not always follow this
sequalae
Prevention
Use lowest effective dose of LA.
Aspirate needle or catheter prior to local administration. (2% false negative)
Incremental doses
Intravascular marker when injecting potentially toxic doses of LA
Use ultrasound guidance.
May get symptoms of mild systemic toxicity with subtoxic doses in
unpremedicated patients
Treatment
Airway management
Hypoxia and acidosis will potentiate ALST
Lipid Emulsion Therapy
1.5 ml/kg of 20% lipid emulsion bolus
Infusion of 0.25ml/kg/min continued for 10 min after circulatory stability is
achieved
If stability is not achieved, consider another bolus and infusion of
0.5ml/kg/min over 10 min.
Max dose 10ml/kg
Propofol is not a substitute for lipid emulsion
If treatment fails, contact closest facility capable of cardio-pulmonary
bypass to consider transfer.
Treatment (continued)
Seizures
Benzodiazepines
Propofol in small doses
Cardiac Arrest
ACLS with modifiers
Use small doses of epinephrine (large doses may inhibit lipid therapy)
Vasopressin not recommended
Avoid CCB and Beta-Blockers
Amiodarone for ventricular arrhythmias
Preparing your OB
Department
Communication Exercise
REAP Indicators & Recommendations
The OB department is prepared to recognize and treat anesthesia/analgesia-
related emergencies. P&Ps, protocols, checklists, and/or order sets should
provide guidance for recognizing and responding to:
Epidural-related emergencies
Malignant hyperthermia
Local anesthetic systemic toxicity (LAST)
Equipment/drugs are readily available to the L&D and postpartum nursing staff
and anesthesia provider.
Malignant Hyperthermia
Create P&P with Surgery Department
Dantrium Box
Emergency Checklist in the C-Section Suite
Staff Education
Malignant Hyperthermia Drill
Malignant Hyperthermia Emergency Checklist
LAST
Update Epidural P&P to include LAST recognition and
treatment
Staff Education
LAST Simulation/Drill
Example of Emergency Conditions policy
statement Report the following complications immediately to anesthesia/obstetrics provider
and immediately discontinue epidural infusion as appropriate (note that LAST can
be immediate or take up to 30 minutes to manifest):
Fetal heart rate changes (Drop in FHR 20-30% below pre-anesthetic levels or becomes a
Category II or III tracing)
Intravascular complications: Metallic taste in mouth, tinnitus, dizziness, vertigo,
numbness of lips and tongue, disorientation, incoherent speech, muscle twitching,
nausea/vomiting, convulsions
Intrathecal complications: Unexpected progression of leg weakness, sudden loss of
consciousness, severe hypotension, bradycardia/tachycardia, respiratory depression,
cardiac arrest
Example of Emergency Conditions policy
statement (Continued) Place patient in left or right lateral position.
Administer oxygen per OxyMask at 10 liters per minute.
Administer fluid bolus of 200-500ml of LR or non- glucose fluid if one hasn’t already been given.
In the event of rapid deterioration, respiratory arrest, or cardiac arrest, call CODE BLUE. Notify anesthesia and obstetrics providers immediately if not already present
Discontinue Epidural infusion
Manage airway, breathing, and circulation according to ACLS guidelines
If LAST is suspected, implement lipid emulsion therapy protocol (Fat Emulsion/Liposyn in Pyxis) per provider order.
1.5 ml/kg of 20% lipid emulsion bolus
Infusion of 0.25ml/kg /min continued for 10 min after circulatory stability is achieved.
If stability is not achieved consider another bolus and infusion of 0.5ml/kg/min
Upper limit on dosing is 10ml/kg over 30 min
Consider transfer for specialized care at a higher level facility
References (MH)
References (LAST)
American Society of Regional Anesthesia (2011). Checklist for treatment of
local anesthetic systemic toxicity. Retrieved May 22, 2019, from
http://www.asra.com
Nagelhout, J.J., Plaus, K.L. (2014) Nurse Anesthesia (5th ed.). St. Louis:
Elsevier Saunders.
Nagelhout, J. (2014). Pharmacology 2. Pasadena: California State University.
