Association Between the Apolipoprotein E4 and Postoperative Cognitive Dysfunction in Elderly Patients Undergoing Intravenous Anesthesia and Inhalation Anesthesia

Abstract

A s the population older than 65 years increases, it is possible that advanced age could be used as a barrier to admission for high-level care, especially in the era of resource-limited critical care environments. Difficult decisions regarding access to critical care for the elderly will become increasingly important. Research has found that, in preselected intensive care unit (ICU) cohorts, the severity of illness and acute physiology have a greater effect on prognosis than age alone. Data on patients admitted to and managed within medical high-dependency units (MHDUs) rather than ICUs are lacking. These patients have purely medical diagnoses that may require more intensive observation, treatment, and nursing care than available on a general ward. These units typically also provide noninvasive ventilation, ionotropic support, and hemodialysis but not hemofiltration. This study was designed to determine whether age is a predictor of mortality in patients admitted to and managed in a dedicated MHDU; other variables that predict mortality and changes in functional status of these patients were also examined.Data on 100 consecutive patients were collected prospectively observed during a 3-month period. Patients were older than 18 years and admitted with an emergency medical diagnosis. Data included patient characteristics, main admission diagnosis, preadmission functional status, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores at the highest level in the first 24 hours of admission, Charlson comorbidity index, number of organs supported, days spent on MHDU, and total hospital length of stay. Functional status was rated as independent, minimal assistance, moderate assistance, and nursing care. The primary end point was all-cause 30-day mortality. Age was categorized as younger than 65 years, 65 to 74 years, and older than 75 years.The mean patient age was 66 years; 41% were younger than 65 years, 29% were 65 to 74 years, and 30% were aged older than 75 years. Sixty-three patients were independent, and 25, 6, and 6 required minimal assistance, moderate assistance, and nursing care, respectively. The most common cause for admission was respiratory failure from pneumonia and exacerbations of chronic obstructive pulmonary disease or asthma (28%), sepsis (22%), and gastrointestinal bleeding (10%). Sixteen patients received double-organ support, and 1 had 3 organ systems that required support. The overall mortality rate at 30 days was 21%. Mortality rates for the 3 age groups were 12%, 31%, and 23%, respectivelyVnot a statistically significant difference. The 30-day mortality rate was higher in patients requiring 2 or more organ support, those requiring moderate assistance or nursing home care before admission, and those with an APACHE II score of 25 or higher. No differences were seen when the group was split by age, sex, admission diagnosis, or Charlson comorbidity index. Older and younger patients with better APACHE II scores had no difference in 30-day mortality (10% vs 22%), nor did those with hig...

Effects of anesthetics on early postoperative cognitive outcome and intraoperative cerebral oxygen balance in patients undergoing lung surgery: a randomized clinical trial

“…5 Recently, Cai et al reported that POCD in patients receiving inhalation anesthesia was higher than in patients receiving intravenous anesthesia, particularly in inhalation anesthesia patients harbouring the apolipoprotein E e4 allele associated with Alzheimer's disease. 6 Thus, choice of anesthesia may be an additional factor influencing the incidence of POCD. Several additional clinical studies have also compared the incidence of POCD in patients undergoing intravenous vs inhalation anesthesia.…”

Difficulties in Understanding Postoperative Cognitive Dysfunction

“…Until now, most studies on POCD have been focused on adults, especially elderly patients (1,8,19). Morgan et al (57) were the first to focus on the neuropsychological effects of general anesthesia on pediatric patients, namely, 5 years old children, and reported that children would present cognitive decline after anesthesia with halothane or nitric oxide.…”

“…The patient-relevant risk factors reported in previous studies included little education (1), preoperative silent brain ischemia (5), preoperative subclinical dementia (6), pre-existed metabolic syndrome (7), hereditary vulnerabilities such as apolipoprotein E4 (8,9) which is a gene polymorphism of apolipoprotein E, and obesity (10), etc. The possible anesthesia-relevant risk factors included premedication, specific inhaled or intravenous anesthetic agents, the duration and depth of anesthesia, and the imbalances of internal environments such as intraoperative hyperglycemia in non-diabetic patients (11), etc.…”

A reply

“…Cai et al. should have been included in the final analysis of the effect of intravenous or inhalational anaesthesia on the outcome of postoperative delirium . These corrections do not alter the findings of the meta‐analysis, as the odd ratio (95% CI) for postoperative delirium following intravenous anaesthesia is 1.03 (0.02–59.5) (Fig.…”