VD/VT

In medicine, the ratio of physiologic dead space over tidal volume (V_D/V_T) is a routine measurement, expressing the ratio of dead-space ventilation (V_D) to tidal ventilation (V_T), as in physiologic research or the care of patients with respiratory disease.^[1]

Equation

{\frac {V_{D}}{V_{T}}}={\frac {P_{a}CO_{2}-P_{E}CO_{2}}{P_{a}CO_{2}}}

References

^ Raymond LW (1978). "The alveolar air equation abbreviated". Chest. 74 (6): 675–6. doi:10.1378/chest.74.6.675. PMID 738126.

[pmid738126-1] Raymond LW (1978). "The alveolar air equation abbreviated". Chest. 74 (6): 675–6. doi:10.1378/chest.74.6.675. PMID 738126.

[1]

v t e Mechanical ventilation
Fundamentals	Modes of mechanical ventilation Mechanical ventilation in emergencies Nomenclature of mechanical ventilation
Modes	IMV/SIMV CMV ACV CSV PAP BPAP/NIV CPAP APRV MMV PAV ASV HFV List of modes by category
Related illness	ARDS Atelectotrauma Biotrauma Pulmonary barotrauma Pulmonary volutrauma Rheotrauma 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 Mechanical power