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;

${\displaystyle M_{PAW}={\frac {f\times T_{i}}{60}}\times (P_{IP}-PEEP)+PEEP}$

${\displaystyle M_{PAW}={\frac {F_{1}}{F_{1}+F_{E}}}\times P_{IP}+\left(1-{\frac {F_{1}}{F_{1}+F_{E}}}\right)\times PEEP}$

${\displaystyle M_{PAW}={\frac {(R)(T_{i})(P_{I})+[60-(R)(T_{i})](PEEP)}{60}}}$

${\displaystyle M_{PAW}={\frac {f\times T_{i}}{60}}\times (P_{IP}-PEEP)+PEEP}$[3]

${\displaystyle M_{PAW}={\frac {(T_{i}\times P_{IP})+(T_{e}\times PEEP)}{T_{i}+T_{e}}}}$

Unique mechanical ventilation equations

Mean airway pressure in airway pressure release ventilation

${\displaystyle M_{PAW}={\frac {(P_{high}\times T_{high})\,+(P_{low}\times T_{low})}{T_{high}+T_{low}}}}$

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.