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

↑ 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.
↑ 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.
↑ David W. Chang (1999). Respiratory care calculations. Cengage Learning. pp. 251–. ISBN 978-0-7668-0517-0. Retrieved 30 March 2012.

Mechanical ventilation

Fundamentals	Modes of mechanical ventilation Mechanical ventilation in emergencies Mechanical ventilation in neonates Nomenclature of mechanical ventilation

Modes	IMV/SIMV CMV ACV CSV PAP BPAP CPAP APRV MMV PAV ASV HFV

Related illness	ARDS Pulmonary barotrauma Pulmonary volutrauma Ventilator-associated pneumonia Oxygen toxicity Ventilator-associated lung injury

Pressure	P_EEP FiO₂ Δ_P P_IP P_S P_AW P_plat

Volumes	V_T V_E V_f

Other	C_dyn C_static P_AO₂ V_D/V_T OI A-a gradient

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