Why left lateral position in recovery position?

Answer 1

Left, rather than right, lateral recovery position reduces the pressure on the inferior vena cava (the main vein bringing blood from the lower body to the heart) in patients with increased mass or pressure in the abdomen (e.g. pregnancy). This helps the blood flow back to the heart, to then be pumped around the body again. Pressure on the inferior vena cava, reducing venous return (blood flow to the heart) can result in reduced blood flow, leading to shock.