50% of patients who undergo esophageal and/or lung resection suffer from acute brain dysfunction or delirium postoperatively. Delirium is a state of brain failure characterized by disturbance of consciousness with reduced ability to focus, sustain, or shift attention that occurs over a short period of time and tends to fluctuate over the course of the day. Presence of delirium in the post-operative phase is associated with a longer length of both intensive care unit and hospital stay, increased health-care costs, long-term functional and cognitive decline, and an increased risk of in-hospital and post-discharge mortality.
Haloperidol primarily acts by blocking dopamine (D2) receptors. This dopamine blockade in the cerebral cortex improves cognition and reduces delirium. Along with the dopamine blockade, haloperidol has anti-inflammatory properties. It inhibits production of lipopolysaccharide induced pro-inflammatory cytokines, interleukin (IL-1) and tumor necrosis factor alpha (TNF-α). Haloperidol also increases levels of Interleukin -1 receptor antagonist (IL-1RA), an anti-inflammatory cytokine that blocks the action of other pro-inflammatory cytokines. If unchecked, the inflammatory cytokines cause impaired concentration, sleep disturbances, and agitation the cardinal symptoms of delirium; and induce a reduction in cholinergic activity. Given the inhibitory effect of acetylcholine on certain cytokines such as interleukin-6, a repetitive cycle of inadequate regulation of inflammation due to cholinergic depletion ensues. Haloperidol with its anti-inflammatory properties seeks to mitigate this repetitive vicious cycle.
