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Question 1Flight Physiology

At high altitude the fraction of oxygen in ambient air remains about 21%, yet tissue hypoxia develops. Which principle best explains this?

  1. Oxygen molecules become chemically less reactive in cold air
  2. The percentage of oxygen in the atmosphere decreases with altitude
  3. The partial pressure of oxygen decreases as barometric pressure falls Correct answer.
  4. Carbon dioxide progressively displaces oxygen from the alveoli

Explanation

Hypoxia at altitude results from a fall in the partial pressure of oxygen, which is the product of the oxygen fraction and barometric pressure. Because barometric pressure falls with altitude, alveolar and arterial oxygen tensions fall even though the fraction of oxygen stays constant.

Question 2Flight Physiology

A patient with an endotracheal tube is transported in an unpressurized aircraft that climbs to 9,000 feet. What happens to the tube cuff?

  1. Cuff volume decreases and the seal is lost
  2. Cuff volume is unchanged because the cuff is filled with saline
  3. Cuff volume increases and may compress the tracheal mucosa Correct answer.
  4. Cuff pressure falls because the gas cools during ascent

Explanation

Boyle's law states that at constant temperature the volume of a gas varies inversely with pressure. As cabin altitude rises and ambient pressure falls, air trapped in the cuff expands, raising both volume and pressure against the tracheal wall.

Question 3Flight Physiology

At 35,000 feet, the approximate time of useful consciousness after loss of oxygen is:

  1. 3 to 5 minutes
  2. 10 to 15 seconds
  3. 30 to 60 seconds Correct answer.
  4. 1 to 2 minutes

Explanation

Time of useful consciousness shortens steeply as altitude increases because oxygen stores in blood and lung are small. At 35,000 feet it is typically about 30 to 60 seconds, falling to roughly 15 to 20 seconds near 40,000 feet.

Question 4Flight Physiology

Which finding is typically the earliest indication of hypoxia in a conscious adult?

  1. Bradycardia with rising blood pressure
  2. Deep, painful inspirations
  3. Cyanosis of the lips and nail beds
  4. Impaired judgment with a sense of well-being Correct answer.

Explanation

Subtle central nervous system changes such as euphoria, poor self-assessment, and impaired judgment appear first because the brain is most sensitive to falling oxygen tension. Cyanosis is a late and unreliable sign that requires substantial desaturation and reduced perfusion.

Question 5Flight Physiology

During descent, a patient reports increasing ear fullness and pain. What is the most appropriate instruction?

  1. Swallow, yawn, or perform a Valsalva maneuver Correct answer.
  2. Pinch the nose and inhale sharply through the nose
  3. Apply warm compresses over the ear canal
  4. Breathe rapidly through a wide-open mouth

Explanation

Middle ear pressure must be equalized during descent, when ambient pressure rises and the eardrum is pushed inward. Swallowing, yawning, and a gentle Valsalva maneuver open the eustachian tube and allow air to enter the middle ear.

Question 6Flight Physiology

Acceleration forces acting from head to foot (+Gz) most directly produce which effect?

  1. Rupture of the tympanic membrane
  2. Decreased cerebral perfusion with grayout or blackout Correct answer.
  3. Increased venous return with hypertension
  4. Blood pooling in the head with facial congestion

Explanation

Positive +Gz acceleration drives blood away from the head toward the lower body, reducing cerebral perfusion pressure. Progressive reduction in retinal and then cerebral blood flow causes grayout followed by loss of consciousness.

Question 7Flight Physiology

A patient with smoke inhalation has a pulse oximetry reading of 99%. Why is this value misleading?

  1. High peripheral perfusion makes oximetry overestimate saturation
  2. Smoke inhalation causes anemia that oximetry cannot detect
  3. Pulse oximetry becomes inaccurate only below 80% saturation
  4. Two-wavelength oximetry cannot distinguish carboxyhemoglobin from oxyhemoglobin Correct answer.

Explanation

Standard pulse oximeters use two wavelengths and read carboxyhemoglobin much like oxyhemoglobin, producing a falsely reassuring saturation. Co-oximetry or blood gas analysis with carboxyhemoglobin measurement is needed to detect carbon monoxide poisoning.

Question 8Flight Physiology

Sustained exposure to high-intensity aircraft noise most directly damages which structure?

  1. Cochlear hair cells Correct answer.
  2. Ossicular chain
  3. Tympanic membrane
  4. Eustachian tube

Explanation

Noise-induced hearing loss is sensorineural and results from metabolic and mechanical injury to hair cells in the organ of Corti. These cells do not regenerate, so the loss is permanent.

Question 9Flight Physiology

Which gas law best explains the formation of nitrogen bubbles in decompression sickness?

  1. Henry's law Correct answer.
  2. Charles's law
  3. Boyle's law
  4. Graham's law

Explanation

Henry's law states that the amount of gas dissolved in a liquid is proportional to its partial pressure above the liquid. When ambient pressure falls rapidly, excess dissolved nitrogen comes out of solution and forms bubbles in tissues and blood.

Question 10Flight Physiology

A patient with a small simple pneumothorax has no chest tube and is flown at a cabin altitude of 8,000 feet. What is the greatest concern?

  1. Expansion of trapped pleural air that can produce a tension pneumothorax Correct answer.
  2. Cooling of pleural gas until it liquefies
  3. Accelerated resorption of pleural air causing mediastinal shift
  4. Diffusion of nitrogen from blood into the pleural space

Explanation

Trapped gas in the pleural space expands as ambient pressure falls during ascent, and the expanding collection can compress the lung and shift mediastinal structures. This is why a pneumothorax should be treated or a cabin altitude limited before flight.

Question 11Flight Physiology

An oxygen cylinder stored outdoors in subfreezing weather shows a lower pressure reading, but the quantity of gas in the cylinder is unchanged. Which law explains this?

  1. Boyle's law
  2. Henry's law
  3. Gay-Lussac's law Correct answer.
  4. Dalton's law

Explanation

Gay-Lussac's law states that the pressure of a fixed amount of gas at constant volume is directly proportional to its absolute temperature. A cold cylinder therefore reads a lower pressure even though the number of gas molecules has not changed.

Question 12Flight Physiology

At 10,000 feet, where barometric pressure is about 523 mmHg, the partial pressure of oxygen in humidified tracheal gas is approximately:

  1. 60 mmHg
  2. 100 mmHg Correct answer.
  3. 160 mmHg
  4. 130 mmHg

Explanation

Tracheal oxygen partial pressure equals the oxygen fraction times the difference between barometric pressure and water vapor pressure: 0.21 x (523 minus 47), which is about 100 mmHg. At sea level the same calculation yields roughly 149 mmHg.

Question 13Flight Physiology

A pilot accelerating rapidly in poor visibility senses that the aircraft is pitching up and pushes the nose down. Which illusion is this?

  1. Autokinesis
  2. Somatogravic illusion Correct answer.
  3. The leans
  4. Coriolis illusion

Explanation

Linear acceleration stimulates the otolith organs in a way that is interpreted as a pitch-up attitude. The pilot then pushes the nose down, which can result in a dangerously low flight path or descent.

Question 14Flight Physiology

During a night approach over unlit terrain with no ground reference, which erroneous flight path is most likely?

  1. A lower-than-intended approach path Correct answer.
  2. A false perception of a wider runway
  3. An excessively high approach
  4. Lateral drift away from the centerline

Explanation

The black hole illusion occurs when a bright runway environment is surrounded by darkness, making the aircraft appear higher than it is. The pilot descends too low and flies a shallow approach, risking terrain contact.

Question 15Flight Physiology

Performance and alertness are typically lowest during which period of the day?

  1. 1200 to 1500
  2. 0300 to 0600 Correct answer.
  3. 0700 to 1000
  4. 1900 to 2200

Explanation

The window of circadian low occurs in the early morning hours, roughly 0300 to 0600, when core temperature and alertness reach their nadir. Fatigue-related errors and involuntary sleep episodes are most likely during this period.

Question 16Flight Physiology

Why should a severely hypothermic patient be handled gently and kept horizontal during transport?

  1. Because rough handling can precipitate ventricular fibrillation Correct answer.
  2. Because movement accelerates frostbite of the extremities
  3. Because shivering sharply increases oxygen consumption
  4. To prevent a further rise in blood glucose

Explanation

The cold myocardium is highly irritable, and mechanical stimulation from rough movement or sudden postural change can trigger ventricular fibrillation. Smooth handling and maintaining a horizontal position reduce that risk.

Question 17Flight Physiology

Which factor contributes most to arterial oxygen content?

  1. Inspired oxygen fraction
  2. Minute ventilation
  3. Dissolved oxygen in plasma
  4. Hemoglobin concentration and percent saturation Correct answer.

Explanation

Arterial oxygen content is dominated by oxygen bound to hemoglobin, calculated as 1.34 times hemoglobin times saturation. Dissolved oxygen contributes only about 0.003 times the arterial oxygen tension per deciliter.

Question 18Flight Physiology

Which finding most suggests hyperventilation rather than hypoxia?

  1. Cyanosis of the lips and nail beds
  2. Peripheral paresthesias with carpopedal spasm Correct answer.
  3. Respiratory rate of 24 breaths per minute
  4. Progressive confusion and impaired judgment

Explanation

Hyperventilation lowers arterial carbon dioxide and produces hypocarbic symptoms such as tingling of the hands and face, cramps, and carpopedal spasm. Hypoxia, in contrast, produces altered mental status and may cause cyanosis without those hypocarbic features.

Question 19Flight Physiology

At a cabin altitude of 8,000 feet, a patient's oxygen saturation falls to 86% on a nasal cannula at 2 L/min. What is the most appropriate initial action?

  1. Place the patient supine and continue monitoring
  2. Document the finding and recheck in 30 minutes
  3. Increase the inspired oxygen concentration and consider a lower cabin altitude Correct answer.
  4. Reduce the flow rate to prevent carbon dioxide retention

Explanation

Desaturation at altitude reflects a reduced alveolar oxygen tension that a low-flow cannula may not overcome. Escalating to a high-concentration device and requesting a lower cabin altitude addresses the cause rather than observing a deteriorating trend.

Question 20Flight Physiology

A patient develops severe frontal headache and facial pain during descent. What is the most likely cause?

  1. Middle ear effusion from eustachian tube dysfunction
  2. Inner ear decompression related to a patent foramen ovale
  3. Failure of the sinus ostia to equalize pressure Correct answer.
  4. Dental barotrauma from an untreated cavity

Explanation

Sinus barotrauma occurs when a blocked ostium prevents pressure equalization, and the frontal sinus is most commonly affected. Pain is worst during descent, when ambient pressure rises and gas trapped in the sinus contracts relative to the surrounding pressure.

Question 21Flight Physiology

A patient at a cabin altitude of 8,000 feet, where barometric pressure is 565 mmHg, is receiving 28% oxygen by Venturi mask. With an arterial carbon dioxide tension of 40 mmHg, the alveolar oxygen tension is approximately:

  1. 125 mmHg
  2. 145 mmHg
  3. 95 mmHg Correct answer.
  4. 65 mmHg

Explanation

The alveolar gas equation gives 0.28 times (565 minus 47) minus 40 divided by 0.8, which equals about 95 mmHg. Ignoring the carbon dioxide term overestimates the result at about 145 mmHg.

Question 22Flight Physiology

A patient has a hemoglobin of 15 g/dL, arterial saturation of 90%, and arterial oxygen tension of 60 mmHg. The arterial oxygen content is approximately:

  1. 18.3 mL/dL Correct answer.
  2. 13.5 mL/dL
  3. 20.1 mL/dL
  4. 9.0 mL/dL

Explanation

Content equals 1.34 times hemoglobin times saturation plus 0.003 times arterial oxygen tension: 1.34 x 15 x 0.90 gives 18.09, plus 0.18 from dissolved oxygen, totaling about 18.3 mL/dL.

Question 23Flight Physiology

Which finding most suggests arterial gas embolism rather than decompression sickness?

  1. Shoulder pain that improves after descent
  2. Sudden focal neurologic deficit within minutes of a rapid ascent Correct answer.
  3. Gradual onset of fatigue and joint aching over several hours
  4. Itching with a mottled rash over the trunk

Explanation

Arterial gas embolism results from gas entering the arterial circulation and obstructing cerebral vessels, producing abrupt focal deficits, often within minutes of surfacing or rapid decompression. Decompression sickness more often evolves over minutes to hours with joint pain, rash, or fatigue.

Question 24Flight Physiology

Whole-body vibration in the 4 to 8 Hz range is most closely associated with which effect?

  1. Immediate loss of consciousness
  2. Isolated peripheral vasoconstriction
  3. Chest and abdominal resonance with respiratory discomfort Correct answer.
  4. Blurred vision from eyeball resonance

Explanation

The trunk and abdominal contents resonate in the 4 to 8 Hz range, producing chest discomfort, dyspnea, and abdominal symptoms. Higher frequencies in roughly the 10 to 20 Hz range are associated with head resonance and visual blurring.

Question 25Flight Physiology

Why does prolonged breathing of 100% oxygen promote absorption atelectasis?

  1. Oxygen breathing increases surfactant production and stiffens the alveoli
  2. Oxygen is more soluble in blood than nitrogen and diffuses out of the alveoli slowly
  3. Oxygen raises alveolar surface tension and directly collapses small airways
  4. Nitrogen is washed out, so alveoli contain only oxygen, which is absorbed faster than it is replaced Correct answer.

Explanation

Nitrogen normally splints alveoli open because it is poorly absorbed. When it is replaced by oxygen, gas moves into the blood faster than ventilation can replenish it, so units with low ventilation collapse.

Question 26Flight Physiology

A patient with severe anemia has a normal arterial oxygen tension and a normal oxyhemoglobin saturation but develops tissue hypoxia. Which type of hypoxia is present?

  1. Hypemic hypoxia Correct answer.
  2. Histotoxic hypoxia
  3. Stagnant hypoxia
  4. Hypoxic hypoxia

Explanation

Hypemic (anemic) hypoxia occurs when the oxygen-carrying capacity of the blood is reduced by a deficiency of, or dysfunction in, hemoglobin, even though arterial oxygen tension and saturation are normal. Delivery depends on both saturation and hemoglobin mass, so anemia lowers oxygen content and tissue delivery.

Question 27Flight Physiology

After a rapid decompression to a cabin altitude of 35,000 feet, approximately how long is the time of useful consciousness in a healthy adult?

  1. 2 to 3 minutes
  2. 30 seconds to 1 minute Correct answer.
  3. 15 to 20 seconds
  4. 5 to 10 minutes

Explanation

Time of useful consciousness shortens as altitude rises because alveolar oxygen tension falls faster than protective reflexes can respond. At 35,000 feet the accepted range is roughly 30 seconds to 1 minute, and it falls to about 15 to 20 seconds at 40,000 feet.

Question 28Flight Physiology

Which nutrient is required for regeneration of rhodopsin, the photopigment used by rod cells for night vision?

  1. Vitamin E
  2. Thiamine
  3. Vitamin C
  4. Vitamin A Correct answer.

Explanation

Rhodopsin is formed from the protein opsin and the vitamin A derivative retinal. Rod cells dominate dim-light vision, so vitamin A deficiency impairs dark adaptation and night vision before it affects daylight acuity.

Question 29Flight Physiology

During descent, which structure must be actively opened to equalize pressure across the tympanic membrane?

  1. The oval window
  2. The eustachian tube Correct answer.
  3. The round window
  4. The external auditory canal

Explanation

The eustachian tube connects the middle ear to the nasopharynx and is the only route for pressure equalization across the tympanic membrane. It is normally closed and must be opened by swallowing, yawning, or a Valsalva maneuver, which is why descent barotrauma is more common in patients with congestion.

Question 30Flight Physiology

A pilot in a sustained constant-rate turn under instrument conditions bends the head forward to read a chart and immediately develops severe vertigo and nausea. Which illusion is this?

  1. Graveyard spiral
  2. Autokinesis
  3. Somatogravic illusion
  4. Coriolis illusion Correct answer.

Explanation

The Coriolis illusion is caused by cross-coupled stimulation of the semicircular canals when the head moves out of the plane of a sustained rotation. The resulting tumbling sensation and nausea can provoke abrupt, inappropriate control inputs.

Question 31Flight Physiology

Which finding is an early manifestation of central nervous system oxygen toxicity?

  1. Productive cough with substernal burning
  2. Tunnel vision with perioral twitching Correct answer.
  3. Progressive bradycardia with warm, dry skin
  4. Bilateral hearing loss

Explanation

Central nervous system oxygen toxicity begins with visual field constriction, tinnitus, nausea, irritability, and muscle twitching, and can progress rapidly to seizures. Pulmonary oxygen toxicity, by contrast, develops after prolonged exposure with cough, chest burning, and dyspnea.

Question 32Flight Physiology

A patient with suspected decompression sickness is receiving high-flow oxygen during transport. Which mechanism best explains the therapeutic benefit of 100% oxygen?

  1. It raises the circulating hemoglobin concentration
  2. It accelerates nitrogen washout by lowering the partial pressure of nitrogen in the blood Correct answer.
  3. It increases lung compliance and reduces the work of breathing
  4. It constricts peripheral vessels and limits edema formation

Explanation

Breathing 100% oxygen washes nitrogen out of the alveoli, creating a steep gradient that draws nitrogen from bubbles into the blood and speeds bubble resolution. Denitrogenation also reduces the volume of gas available to expand if cabin altitude increases.

Question 33Flight Physiology

After a single recreational dive that required no decompression stops, what is the minimum recommended surface interval before flying in an aircraft with a cabin altitude of 8,000 feet?

  1. 24 hours
  2. 12 hours Correct answer.
  3. 2 hours
  4. 6 hours

Explanation

Residual nitrogen after diving can precipitate decompression sickness when ambient pressure falls during flight. Guidelines recommend waiting at least 12 hours after a single no-decompression dive, and 24 hours or more after decompression-stop, repetitive, or multi-day diving.

Question 34Flight Physiology

During climb in an unpressurized aircraft, a passenger reports severe pain in a tooth with a recent deep restoration but shows no signs of infection. What is the most likely cause?

  1. Barotrauma of the maxillary sinus
  2. Expansion of trapped gas beneath the restoration Correct answer.
  3. Ischemic pulp necrosis from reduced oxygen tension
  4. Referred pain from the temporomandibular joint

Explanation

Barodontalgia results from gas trapped beneath a restoration or within a diseased pulp expanding as ambient pressure falls during ascent. The pain is typically sharp, localized to the affected tooth, and resolves with descent or removal of the gas space.

Question 35Flight Physiology

Which presentation is most consistent with a slow, insidious cabin decompression?

  1. Gradually increasing ear and sinus pressure with abdominal gas discomfort Correct answer.
  2. A loud bang with immediate fog formation in the cabin
  3. Immediate incapacitation of all occupants
  4. Sudden severe chest pain with hemoptysis

Explanation

In a slow decompression, pressure changes gradually enough that the classic sudden noise and fog are absent, and the earliest clues are subtle: ear and sinus pressure, abdominal bloating, and delayed hypoxia. Recognition often depends on the cabin altitude warning rather than symptoms.

Question 36Flight Physiology

A crew member travels eastward across eight time zones. Which statement best describes the resulting circadian effect?

  1. The body clock must be phase-advanced, which is generally harder than phase-delaying Correct answer.
  2. Adaptation requires no more than one day regardless of the number of time zones crossed
  3. Crew members are unaffected if they keep their home-base meal schedule
  4. Symptoms are typically milder than after equivalent westward travel

Explanation

Eastward travel requires the circadian pacemaker to advance, because the body must sleep and wake earlier relative to its internal clock. Phase advances are harder to achieve than the delays produced by westward travel, so eastward jet lag is usually more severe.

Question 37Flight Physiology

Which is typically the earliest sign of hypoxia in a healthy adult at altitude?

  1. Cyanosis of the nail beds
  2. Bradycardia with warm, flushed skin
  3. Slow, deep respirations with hiccups
  4. Impaired judgment with a sense of well-being Correct answer.

Explanation

Cerebral effects appear first, so subtle errors in judgment, euphoria, and loss of self-critique precede dramatic physical signs. Because the patient's own ability to recognize the deficit is impaired, objective monitoring and a high index of suspicion are essential.

Question 38Flight Physiology

At altitude, a rise in red cell 2,3-diphosphoglycerate produces which change in oxygen transport?

  1. Increased hemoglobin oxygen affinity with reduced tissue delivery
  2. A rightward shift of the oxyhemoglobin curve, favoring oxygen unloading at the tissues Correct answer.
  3. Reduced arterial oxygen content with unchanged saturation
  4. A leftward shift of the oxyhemoglobin curve, favoring oxygen loading in the lungs

Explanation

2,3-DPG binds deoxyhemoglobin and stabilizes the tense state, shifting the dissociation curve to the right and lowering hemoglobin affinity for oxygen. This increases unloading at the tissues at the cost of slightly lower saturation for any given oxygen tension.

Question 39Flight Physiology

A patient with sickle cell disease requires air medical transport at a cabin altitude of 8,000 feet. Which measure most directly reduces the risk of a vaso-occlusive crisis?

  1. Keeping the patient cool and restricting oral intake
  2. Positioning the patient upright and avoiding all fluids
  3. Withholding supplemental oxygen to avoid suppressing respiratory drive
  4. Maintaining hydration and providing supplemental oxygen to prevent sickling Correct answer.

Explanation

Hypoxemia, dehydration, acidosis, and cold all promote hemoglobin S polymerization and sickling. Maintaining hydration and correcting hypoxemia during flight addresses two of the most modifiable triggers.

Question 40Flight Physiology

Above approximately what altitude would unprotected body fluids begin to vaporize at body temperature, making a pressure suit mandatory?

  1. 100,000 feet
  2. 63,000 feet Correct answer.
  3. 18,000 feet
  4. 34,000 feet

Explanation

The Armstrong line, near 63,000 feet, is the altitude at which ambient pressure falls below the vapor pressure of water at body temperature. Above it, exposure causes ebullism, with vaporization of fluids in the lungs, eyes, and circulation.

Question 41Patient Assessment and Stabilization

During the primary assessment of a trauma patient, which action should be performed first?

  1. Assess airway with C-spine protection Correct answer.
  2. Establish two large-bore IV lines
  3. Obtain a complete set of vital signs
  4. Auscultate breath sounds in all fields

Explanation

The primary survey follows an ABCDE sequence, and airway patency with cervical spine protection is addressed before breathing, circulation, and exposure. Vital signs and IV access are obtained during circulation and resuscitation. Lung auscultation belongs to the breathing step.

Question 42Patient Assessment and Stabilization

A patient's pulse oximeter reads 86% on room air. This value most directly reflects which condition?

  1. Anemia
  2. Metabolic acidosis
  3. Hypercapnia
  4. Hypoxemia Correct answer.

Explanation

Pulse oximetry estimates arterial hemoglobin oxygen saturation, and a value below 90% indicates hypoxemia. It does not directly measure carbon dioxide, acid-base status, or hemoglobin concentration.

Question 43Patient Assessment and Stabilization

A patient opens the eyes only in response to painful stimulation. Which Glasgow Coma Scale eye-opening score is assigned?

  1. 1
  2. 4
  3. 3
  4. 2 Correct answer.

Explanation

The GCS eye-opening scale is spontaneous 4, to voice 3, to pain 2, and none 1. Opening only to pain therefore receives a score of 2.

Question 44Patient Assessment and Stabilization

Which vital sign change is typically the earliest indicator of compensated hypovolemic shock in an adult?

  1. Increasing heart rate Correct answer.
  2. Falling systolic blood pressure
  3. Rising body temperature
  4. Decreasing respiratory rate

Explanation

Baroreceptor-mediated tachycardia occurs early to maintain cardiac output as volume is lost. Systolic blood pressure typically falls later, after a larger volume deficit has developed.

Question 45Patient Assessment and Stabilization

Which breath sound is most characteristic of upper airway obstruction?

  1. Pleural friction rub
  2. Stridor Correct answer.
  3. Crackles
  4. Wheezing

Explanation

Stridor is a high-pitched inspiratory sound caused by turbulent flow through a narrowed upper airway such as the larynx or trachea. Crackles reflect alveolar fluid, wheezing reflects lower airway narrowing, and a rub reflects pleural inflammation.

Question 46Patient Assessment and Stabilization

Which pulse site is most appropriate for assessing a central pulse in an unresponsive adult during resuscitation?

  1. Dorsalis pedis artery
  2. Radial artery
  3. Temporal artery
  4. Carotid artery Correct answer.

Explanation

The carotid artery is a central pulse and remains palpable longer in low-flow states than peripheral pulses. Peripheral pulses may be absent even when cardiac activity is present.

Question 47Patient Assessment and Stabilization

A patient with diabetes is confused and diaphoretic, and the point-of-care glucose is 42 mg/dL. Which intervention is the priority?

  1. Obtain a 12-lead ECG
  2. Start a norepinephrine infusion
  3. Give oral glucose gel
  4. Administer IV dextrose Correct answer.

Explanation

Symptomatic hypoglycemia requires immediate glucose administration. IV dextrose is preferred in a confused patient because oral intake risks aspiration and may not be tolerated.

Question 48Patient Assessment and Stabilization

Which end-tidal carbon dioxide value is within the expected range for a normoventilated adult?

  1. 40 mmHg Correct answer.
  2. 55 mmHg
  3. 15 mmHg
  4. 25 mmHg

Explanation

Normal end-tidal carbon dioxide approximates 35 to 45 mmHg in a normoventilated adult. Lower values suggest hyperventilation or poor perfusion, while higher values suggest hypoventilation.

Question 49Patient Assessment and Stabilization

A patient with blunt chest trauma has hypotension, absent breath sounds on the right, and tracheal deviation to the left. Which condition is most likely?

  1. Massive hemothorax on the right
  2. Right tension pneumothorax Correct answer.
  3. Flail chest
  4. Cardiac tamponade

Explanation

Tension pneumothorax produces ipsilateral absent breath sounds and shifts mediastinal structures away from the affected side, impairing venous return and causing hypotension. These findings constitute a clinical diagnosis requiring immediate decompression.

Question 50Patient Assessment and Stabilization

An adult with a traumatic brain injury has a Glasgow Coma Scale score of 8. Which airway management is most appropriate?

  1. Endotracheal intubation Correct answer.
  2. Oropharyngeal airway alone
  3. High-flow nasal cannula
  4. Nasopharyngeal airway and observation

Explanation

A GCS score of 8 or less indicates coma with loss of airway protective reflexes, so a definitive airway with endotracheal intubation is indicated. Basic airways do not protect against aspiration, and high-flow nasal cannula does not secure the airway.