Airway, Respiration & Ventilation
Oxygenation vs. ventilation
Airway management is three separate problems: keeping the tube open, getting oxygen across the alveolar membrane, and moving carbon dioxide out. A patient can be oxygenating (pulse oximetry 98%) while failing to ventilate - a rising CO2 with a normal SpO2 is the classic trap. Assess rate, depth, effort, and mental status; a silent chest or decreasing respiratory effort is a late and dangerous sign.
Basic and advanced airways
Position first: head-tilt/chin-lift for the medical patient, jaw-thrust for suspected spinal injury. Suction is a treatment, not a delay - blood, vomit, and secretions outrank any device. Size an OPA from the corner of the mouth to the earlobe; an OPA in a patient with a gag reflex risks vomiting and laryngospasm. NPAs help when the mouth cannot be opened; use cautiously with midface trauma. A BVM delivers 21% room air unless attached to oxygen; squeeze over one second, just enough for visible chest rise.
Adjuncts and monitoring
Waveform capnography confirms tube placement and detects displacement faster than auscultation; a sudden loss of waveform means check the tube, not the monitor. CPAP is for the awake, spontaneously breathing patient in distress (pulmonary edema, COPD).
Trap: a question saying the patient breathes 6 times a minute with an SpO2 of 94% tests whether you ventilate rather than simply apply oxygen.
Rule of thumb: with an advanced airway in place, ventilate the adult once every 6 seconds (about 10/min).