Which unit is used to express PEEP in ventilator settings?

Which unit is used to express PEEP in ventilator settings?

• A. mmHg
• B. kPa
• C. psi
• D. cmH2O

Answer: (D)

PEEP is a pressure maintained in the lungs at the end of expiration to keep alveoli open, and it is expressed in centimeters of water (cmH2O). In respiratory therapy, airway pressures on the ventilator—like peak inspiratory pressure, plateau pressure, and PEEP—are routinely given in cmH2O because the values are small and the unit directly reflects the pressure of a column of water. This makes it practical for adjusting ventilation and matching clinical physiology. Other pressure units exist (mmHg, kPa, psi) but they’re not used for ventilator settings; they’re more common in other medical or engineering contexts. For perspective, 1 cmH2O is about 0.735 mmHg and 0.098 kPa, so PEEP values in actual practice (especially in neonates and pediatrics) typically range only a few cmH2O (for example, 4–6 cmH2O). This alignment with the physiologic scale of airway pressures is why cmH2O is the standard unit for expressing PEEP.

PEEP is a pressure maintained in the lungs at the end of expiration to keep alveoli open, and it is expressed in centimeters of water (cmH2O). In respiratory therapy, airway pressures on the ventilator—like peak inspiratory pressure, plateau pressure, and PEEP—are routinely given in cmH2O because the values are small and the unit directly reflects the pressure of a column of water. This makes it practical for adjusting ventilation and matching clinical physiology. Other pressure units exist (mmHg, kPa, psi) but they’re not used for ventilator settings; they’re more common in other medical or engineering contexts. For perspective, 1 cmH2O is about 0.735 mmHg and 0.098 kPa, so PEEP values in actual practice (especially in neonates and pediatrics) typically range only a few cmH2O (for example, 4–6 cmH2O). This alignment with the physiologic scale of airway pressures is why cmH2O is the standard unit for expressing PEEP.