Pulmonary vascular and right ventricular dysfunction in adult critical care: current and emerging options for management: a systematic literature review

Table 2 Local factors increasing pulmonary vascular tone

Factors increasing pulmonary vascular tone	Additional contributors to elevated PVR in ARDS
High pulmonary arterial pCO₂/low pH	Vasoconstrictor: vasodilator imbalance
Low mixed venous pO₂	Excess ET-1 [361], TXA-1, PDE, 5HT [2]
High sympathetic tone; α-adrenoceptor agonism	Reduced NO, prostanoids [20]
Mechanical effects:	Effects of endotoxin [22, 362]
High airway P_plat; gravity; increased flow (for example, one-lung ventilation)	Endothelial injury [363]
Relating to CPB:	Hypoxic vasoconstriction (80% arteriolar) [22, 364]
Preexisting PH; endothelial injury [17]; protamine [18]	Microthrombosis, macrothrombosis [62, 365]
	Pulmonary vascular remodeling [1]

5-HT, serotonin; ARDS, acute respiratory distress syndrome; CPB, cardiopulmonary bypass; ET-1, endothelin-1; NO, nitric oxide; pCO₂, partial pressure of carbon dioxide; PDE, phosphodiesterase; pO₂, partial pressure of oxygen; P_plat, plateau pressure; PVR, pulmonary vascular resistance; TXA-1, thromboxane A1.

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