CNOR Emergency Situations Review (10%): Malignant Hyperthermia, LAST, OR Fires and Disasters

Emergency questions are a small share of the CNOR, but they are the ones where a confident wrong answer costs a patient the most, and where the right answer is usually a sequence, not a fact. This review uses the public sources CCI's own Study Plan points to, such as MHAUS for malignant hyperthermia, plus national safety sources. Your facility's protocols and CCI's textbook references set the full detail; drug doses are the anesthesia team's decision and are included only where the source states them.

What CNOR area 6 covers, and the 2027 version

CCI's Task & Knowledge Statements list these tasks:

• Identify emergency situations, including difficult airway and robotic emergencies
• Perform nursing interventions for malignant hyperthermia (MH), anaphylaxis, cardiac arrest, trauma, hemorrhage and local anesthetic systemic toxicity (LAST)
• Function as a member of the interdisciplinary team, knowing each member's role
• Safeguard patients and staff from environmental hazards and during disasters, such as fire, toxic fumes, natural disasters, terrorism and active shooter events, including fire and laser safety

The 2027 version on CCI's job analysis page, Emergency Identification and Management, has 17 scored items and the same topics, with fire and laser safety listed as its own knowledge statement. Full prep at launch includes 170 planned Emergency Situations questions with explanations.

Malignant hyperthermia on the CNOR: triggers, signs and the first steps

Triggers. MHAUS describes MH as an inherited disorder triggered by volatile anesthetics (it names halothane, enflurane, isoflurane, desflurane and sevoflurane), the depolarizing muscle relaxant succinylcholine, or both. MedlinePlus adds that only one parent needs to carry the gene.

Signs. MHAUS's recommendations describe a fulminant episode as a hypermetabolic crisis with metabolic and respiratory acidosis, tachycardia, arrhythmias, skeletal muscle rigidity and rhabdomyolysis. After succinylcholine, marked jaw rigidity (masseter muscle rigidity) "may be an initial sign of MH," and MHAUS says to look for other signs such as "tachycardia or hypercarbia that are inappropriate for the clinical situation," generalized rigidity, rising temperature, cola-colored urine and peaked T waves. Don't treat fever as a late sign you can wait for: MHAUS also says temperature elevation "may be the first sign," and recommends core temperature monitoring for general anesthesia lasting more than 30 minutes.

The first steps. MHAUS's crisis page lists four things to do as soon as possible:

1. Notify the surgeon to halt the procedure and discontinue volatile agents and succinylcholine.
2. Get the dantrolene/MH cart and call for help (at a surgery center, call 911). The MHAUS hotline is 1-800-644-9737.
3. Hyperventilate with 100% oxygen at 10 L/min to flush the volatile agent and lower end-tidal CO2.
4. Give IV dantrolene, 2.5 mg/kg rapidly, repeated as needed. Each 20 mg vial of Dantrium or Revonto is reconstituted with 60 mL of sterile water without a bacteriostatic agent; each 250 mg vial of Ryanodex with 5 mL.

It then says to cool the patient if the core temperature is above 39°C or rising rapidly, and to stop cooling below 38°C. The same page covers acidosis, hyperkalemia and urine output, says to treat arrhythmias with standard drugs but avoid calcium channel blockers, and says to transfer the stable patient to a PACU or ICU for at least 24 hours. MHAUS's FAQ adds that dantrolene must be available within 10 minutes of the decision to treat. In Passy's reading, the circulating nurse's most direct part is in steps 2 and 4: getting the cart and help, and helping prepare dantrolene, which for Dantrium or Revonto means 60 mL of diluent for every 20 mg vial. For recall, there are planned flashcards on malignant hyperthermia steps in full prep.

Local anesthetic systemic toxicity (LAST)

The labeling warns that unintended intravascular or intrathecal injection may cause systemic toxicity. FDA-approved bupivacaine labeling on DailyMed, such as the Marcaine label and a repackaged bupivacaine label, lists possible early warning signs of central nervous system toxicity, including restlessness, anxiety, incoherent speech, numbness and tingling of the mouth and lips, metallic taste, tinnitus, dizziness, blurred vision and tremors. Cardiovascular effects include arrhythmias, bradycardia and asystole, and the label says delayed management may lead to acidosis, cardiac arrest and, possibly, death.

The label's management steps start with "immediate attention to the establishment and maintenance of a patent airway" and ventilation with 100% oxygen, a benzodiazepine for seizures, and advanced cardiac life support for circulatory depression, noting that resuscitation may need to be prolonged. It also says the drug should be used only where oxygen, resuscitation equipment and drugs, and trained staff are immediately available.

Lipid emulsion is part of current LAST treatment. A 2021 review in Frontiers in Medicine says the American Society of Regional Anesthesia and Pain Medicine's checklist emphasizes it, recommends starting it after airway management, and says hospitals that use local anesthetics for regional anesthesia or pain management "should stock lipid emulsion preparations." Know where your facility keeps it; dosing comes from the anesthesia team's protocol.

Put together, the sources give these elements: recognize the early signs; secure the airway with 100% oxygen first; a benzodiazepine for seizures; advanced cardiac life support if circulation fails; and lipid emulsion after airway management, under the anesthesia team's protocol. The label also expects the staff and resuscitation equipment to be at hand before the drug is used.

Anaphylaxis in the OR

MedlinePlus describes anaphylaxis as a life-threatening allergic reaction whose symptoms develop "often within seconds or minutes," and its first-aid advice is to use an epinephrine injector immediately if one is available. CCI's Study Plan lists antibiotics, blood, immune response and latex as its key words for this task. In a scenario, sudden breathing difficulty, hives or facial swelling soon after a drug, blood product or latex exposure suggests anaphylaxis, and the response to support is immediate epinephrine and the team's airway management.

Preventing and responding to an OR fire

The Joint Commission's Sentinel Event Alert 68 (October 18, 2023) organizes fire prevention around the fire triangle:

Several of the alert's other actions involve the circulating nurse directly: include a fire risk assessment in every time-out, have saline in the room and extinguishers in the procedural area, define each team member's role in a fire, drill responses (turning off oxidizing gases, using an extinguisher and activating the alarm), plan evacuation to an area that can provide the patient's oxygen, suction and monitoring, and report every fire, even without injury. In an airway fire, the alert says the anesthesiologist "bears primary responsibility" for stopping the flow of oxygen. It also cites the American Society of Anesthesiologists' advice that surgeons tell anesthesia before using an ignition source.

Active shooter, disasters and the team's roles

For active shooter events, the federal guide Incorporating Active Shooter Incident Planning into Health Care Facility Emergency Operations Plans (2014) recommends training staff on "Run, Hide, Fight" as a continuum: run if possible, encouraging others to follow; if not, hide in a secure place and deny the shooter access; and, as a last resort, decide whether to fight. It acknowledges that how a provider responds "will be an intensely personal choice," and asks facilities to tell responders in advance where patients who can't evacuate will be, naming the operating room among those locations. For study, know the order of those options and how your facility's emergency operations plan applies them in the OR.

CCI's outline also lists natural disasters, terrorism, toxic fumes, cardiac arrest, trauma and hemorrhage. Your facility's emergency plans and the references CCI names give the detail; the Study Plan points to chapters for each.

Two original CNOR-style questions on emergency situations

Written by Passy for this guide. They aren't CCI items and don't come from any exam.

Question 1: a rising end-tidal CO2

During a laparoscopic case under sevoflurane, the patient's end-tidal CO2 keeps rising despite increased ventilation, the heart rate reaches 130, and the jaw and limbs are rigid. The anesthesia provider suspects malignant hyperthermia and stops the sevoflurane. What should the circulating nurse do next?

• A. Bring the dantrolene/MH cart and call for help per the MH protocol
• B. Start a cooling blanket first, since fever is the most urgent sign
• C. Prepare a calcium channel blocker to slow the rising heart rate
• D. Wait for a core temperature rise to confirm MH before acting

Keyed answer: A. MHAUS's crisis steps put getting the dantrolene/MH cart and calling for help right after stopping the triggering agents, and its FAQ says dantrolene must be available within 10 minutes of the decision to treat. B is wrong because MHAUS lists cooling later, when core temperature is above 39°C or rising rapidly. C is wrong because MHAUS says to avoid calcium channel blockers when treating MH arrhythmias. D is wrong because MH can show first as hypercarbia, tachycardia or rigidity, and waiting delays treatment.

Question 2: oxygen near the face

A patient under sedation is having a lesion removed from the forehead. Oxygen runs through a nasal cannula, the alcohol-based prep has dried, and the surgeon is about to use electrocautery. What should happen before the cautery is activated?

• A. Surgeon alerts anesthesia; oxygen is cut to the minimum for at least a minute
• B. Oxygen flow is raised so saturation stays high while the cautery is used
• C. Drapes are sealed around the face to keep oxygen close to the airway
• D. Nothing further is needed, since the alcohol prep has already dried

Keyed answer: A. Sentinel Event Alert 68 says to stop or reduce supplemental oxygen to the minimum needed to avoid hypoxia for at least one minute before using an electrosurgical device for head, neck or upper chest procedures, and cites ASA advice that surgeons inform anesthesia before using an ignition source. B adds oxidizer. C traps oxygen under the drapes, which the alert says to prevent. D controls only the fuel; the oxidizer and the ignition source are still in place.

At launch, Redemption challenges planned for full prep bring back the emergency questions you missed.

Your next step for CNOR emergency situations

Find your OR's MH cart, its lipid emulsion supply and the nearest fire extinguisher, and read the protocol kept with each. Then write the first three actions for MH, LAST and an OR fire from memory, check them against this page and your facility's protocols, and test yourself with the 20 free CNOR practice questions.