Mechanical ventilation

Positive end-expiratory pressure (PEEP) improves oxygenation by recruiting collapsed alveoli and keeping them open at the end of expiration. This mechanism increases functional residual capacity (FRC) rather than decreasing it, which directly reduces intrapulmonary shunting and improves ventilation-perfusion matching.

Adjusting the respiratory rate directly alters minute ventilation, which is the primary determinant of carbon dioxide elimination from the blood. While oxygenation is primarily managed by adjusting PEEP and FiO2, changing the respiratory rate is used to normalize arterial pH and carbon dioxide levels.

Normal tidal volume for a healthy adult is approximately 6 to 8 mL/kg of predicted body weight, which provides adequate alveolar ventilation without causing lung strain. A diagram for this topic isn't available yet — the worked example below walks the same reasoning step by step.

• !Read each option carefully — distractors on Mechanical ventilation are designed to look plausible.
• !Re-check the exact wording of the question stem before committing to an answer.
• !Watch the qualifiers ("always", "only", "except") that flip a correct-looking option.

Answer each from memory — you'll see instantly whether you're right and why.

Run a focused 10-question mini-mock on Mechanical ventilation and see it stick.