Shift work is a core part of paramedicine, but growing evidence shows it carries real long-term health risks.

In this episode, with Dr. James Gilbertson, we explore the science behind circadian rhythm disruption, the impacts of sleep deprivation, and how lifestyle and longevity medicine can help mitigate risk.

Key Topics Covered:

• Why shift work affects lifespan and health outcomes
• Circadian rhythm disruption explained
• Links between shift work and:
  • Cardiovascular disease
  • Cancer risk
  • Mental health challenges
• Sleep optimization strategies for shift workers
• Exercise and longevity evidence
• Nutrition approaches that work on shift
• Social connection and cognitive health
• Practical, realistic habits for paramedics

In this episode of Critical Levels, Zach sits down with Dr. Anna-Maria Carvalho, a Royal College–certified emergency physician with a subspecialty in aviation medicine, to unpack what really happens when someone asks, "Is there a medical professional on board?"

From the physiology of flying at 36,000 feet to the realities of managing cardiac arrest in a cramped aircraft cabin, this episode tackles the fears, logistics, and practical considerations of in-flight medical emergencies—especially for paramedics, nurses, and physicians who may be called upon to help.

🫁 The Physiology of Flight

• Why cabin altitude means we're all mildly hypoxic (normal sats ~92–93%)

• How hypoxia increases heart rate, blood pressure, and sympathetic tone

• Why alcohol hits harder in the air

• Why tomato juice tastes better at altitude

• The risk of DVTs and who's most vulnerable

• Barotrauma, ear pain, and when a perforated eardrum can occur

🚨 In-Flight Medical Emergencies

• Incidence: ~1 in 600 flights

• Most common categories:

  • Neurologic

  • Cardiac

  • Respiratory

  • Gastrointestinal

• The realities of flying with chronic disease

• Why more emergencies are happening as more people travel

🧰 What's in the Emergency Medical Kit?

• AED (separate from the medical kit)

• Oxygen & Ambu bag

• Oral airways (intubation equipment varies by airline)

• IV supplies (limited fluids, but enough for medication administration)

• Medications: epinephrine, steroids, bronchodilators, benzodiazepines, antipsychotics, glucose agents, and more

• BP cuff (palpated pressures only—too noisy to auscultate!)

• Pulse oximeter (remember: 93% can be normal)

📡 Ground-Based Medical Support

• Most airlines consult 24/7 emergency physicians on the ground

• Volunteers don't make diversion decisions—the captain does

• Diversions involve significant operational and logistical consequences

• In-flight volunteers are there to assess, stabilize, and communicate

🫀 Cardiac Arrest at 36,000 Feet

• Move to a bulkhead/galley if possible

• Call for additional medical volunteers

• Early AED use

• CPR until ROSC, exhaustion, or medical futility

• Diversion decisions are collaborative and situational

⚖️ The Legal Question

• Good Samaritan protections apply

• Act within scope

• No gross negligence or willful misconduct

• No one has ever been successfully sued for assisting with an in-flight medical emergency

• You are not responsible for diversion decisions

🕊️ When Death Occurs In Flight

• Resuscitation attempts may cease when appropriate

• Diversion is not automatic

• Flight crew are trained to manage these situations professionally and discreetly

• You already have the skills.

• The environment is different—but the fundamentals are the same.

• Recognizing sick vs. not sick is incredibly valuable.

• Most in-flight volunteer diagnoses are ultimately confirmed in hospital.

• About 60% of passengers improve with basic stabilization.

• You are protected when acting in good faith and within scope.

If you've ever hesitated to answer that overhead call, this episode may change your perspective.

On this unique episode, we attend the First60 Toronto Resuscitation Conference and interview several of the speakers. For more detailed information, check out our website, criticallevels.ca