High blood sugar during surgery increases risk of postoperative delirium
Berlin, Germany: Hyperglycemia (high blood sugar) during surgical operation increases the risk of postoperative delirium (POD) but not postoperative cognitive dysfunction (POCD), a recent study in the journal Minerva Anestesiologica. The study further found that the relative time spent in hyperglycemia may play a role in the development of postoperative delirium. Hyperglycemic non-diabetic patients might be at high risk for POD.
The study was also presented at the 2019 annual meeting of the American Society of Anesthesiologists.
Hyperglycemia frequently occurs during major surgery and is associated with adverse postoperative outcomes like increased infection rates and impaired immune function. Gunnar Lachmann, a clinician-scientist at CharitÉ–UniversitÄtsmedizin Berlin, in Berlin, Germany, and colleagues aimed to investigate the influence of intraoperative hyperglycemia on incidences of postoperative delirium and postoperative cognitive dysfunction.
For the purpose, the researchers conducted a subproject of the prospective, observational BioCog study. They analyzed 87 patients at least 65 years of age who were undergoing elective surgery. The researchers measured intraoperative blood glucose levels every 20 minutes via arterial blood gas analyses. Hyperglycemia was defined as blood glucose levels at least 150 mg/dL.
Screening for postoperative delirium was performed twice daily until postoperative day 7 using a variety of measures: the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition; Nursing Delirium Screening Scale; Confusion Assessment Method (CAM); CAM-ICU; and chart review. The researchers also assessed patients for postoperative cognitive dysfunction three months after surgery.
Multivariable logistic regression analysis was used to analyze the influence of intraoperative hyperglycemia on both postoperative delirium and cognitive dysfunction. Secondary endpoints included the time of hyperglycemia, maximum glucose levels, and differences between diabetic and nondiabetic patients.
Key findings of the study include:
- POD occurred in 41 (47.1%), POCD in five (15.2%) patients.
- In two separate multivariable logistic regression models, hyperglycemia was significantly associated with POD (OR 3.86) but not POCD (3.59).
- Relative duration of hyperglycemia was higher in POD patients compared to patients without POD (20 [0; 71] % versus 0 [0; 55] %), whereas the maximum glucose levels during surgery were similar between the two groups.
- Considering only non-diabetic patients, relative duration of hyperglycemia and Glucosemax were significantly higher in patients with POD.
"Intraoperative hyperglycemia was independently associated with POD but not POCD," concluded the authors.
The study, "Intraoperative hyperglycemia increases the incidence of postoperative delirium" is published in the journal Minerva Anestesiologica.