Postperfusion syndrome

Postperfusion syndrome, also known as "pumphead", is a constellation of neurocognitive impairments attributed to cardiopulmonary bypass (CPB) during cardiac surgery. Symptoms of postperfusion syndrome are subtle and include defects associated with attention, concentration, short term memory, fine motor function, and speed of mental and motor responses. Studies have shown a high incidence of neurocognitive deficit soon after surgery, but the deficits are often transient with no permanent neurological impairment.

A study by Newman et al. at Duke University Medical Center published in the New England Journal of Medicine (NEJM) showed an increased incidence of cognitive decline after coronary artery bypass surgery (CABG), both immediately (53 percent at discharge from hospital) and over time (36 percent six weeks, 24 percent at six months, and 42 percent at five years). This study shows an association of neurocognitive decline with CABG, but does not show causation; the study lacks a control group and is considered level II-3 evidence. Also, the statistical calculation of cognitive decline has been demonstrated as the least reliable due to practice effects, measurement error and the regression to the mean phenomenon.

Subsequent studies have compared "on-pump" CABG to off-pump coronary artery bypass (OPCAB)—essentially establishing controls to compare the incidence of neurocognitive decline in CABG with and without the use of CPB. A small study (60 patients total, 30 in each treatment arm) by Zamvar et al. demonstrated neurocognitive impairment at both 1 week and 10 weeks postoperatively. A larger study (281 patients total) by Van Dijk et al. showed CABG surgery without cardiopulmonary bypass improved cognitive outcomes 3 months after the procedure, but the effects were limited and became negligible at 12 months. Furthermore, the Van Dijk study showed no difference between the on-pump and off-pump groups in quality of life, stroke rate, or all-cause mortality at 3 and 12 months. A study by Jenson et al. published in Circulation found no significant difference in the incidence of cognitive dysfunction 3 months after either OPCAB or conventional on-pump CABG.

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