Mean airway pressure

Mean airway pressure typically refers to the mean pressure applied during positive-pressure mechanical ventilation. Mean airway pressure correlates with alveolar ventilation, arterial oxygenation,[1] hemodynamic performance, and barotrauma.[2]

Equations

Determining the real mean airway pressure is a difficult task and there are several equations aimed at determining the real mean airway pressure. Various equations are suggested to be used to determine the actual mean airway pressure;

M_{PAW} = \frac{f * T_i}{60} * (P_{IP} - PEEP) + PEEP
M_{PAW} = \frac{F_1}{F_1+F_E} * P_{IP} + (1 - \frac{F_1}{F_1+F_E}) * PEEP
M_{PAW} = \frac{(R)(T_i)(P_I)+[60-(R)(T_i)](PEEP)}{60}
M_{PAW} = \frac{f * T_i}{60} * (P_{IP} - PEEP) + PEEP [3]
M_{PAW} = \frac{(T_i * P_{IP}) + (T_e * PEEP)}{T_i+T_e}

Unique mechanical ventilation equations

Mean airway pressure in airway pressure release ventilation
M_{PAW} = \frac{(P_{high} * T_{high})\, + (P_{low} * T_{low})} {T_{high} + T_{low}}

References

  1. ↑ Stewart AR, Finer NN, Peters KL (1981). "Effects of alterations of inspiratory and expiratory pressures and inspiratory/expiratory ratios on mean airway pressure, blood gases, and intracranial pressure.". Pediatrics 67 (4): 474–81. PMID 6789294.
  2. ↑ Marini JJ, Ravenscraft SA (1992). "Mean airway pressure: physiologic determinants and clinical importance--Part 2: Clinical implications.". Crit Care Med 20 (11): 1604–16. doi:10.1097/00003246-199211000-00020. PMID 1424706.
  3. ↑ David W. Chang (1999). Respiratory care calculations. Cengage Learning. pp. 251–. ISBN 978-0-7668-0517-0. Retrieved 30 March 2012.
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