Abnormally low Bispectral index and severe hypoglycemia during maintenance of and recovery from general anesthesia in diabetic retinopathy surgery: two case reports

Acute severe hypoglycemia immediately after induction of anesthesia in an elderly patient with type 2 diabetes mellitus: A case report

RATIONALE

Acute severe hypoglycemia immediately following anesthesia induction is a rare but life-threatening complication that is frequently underdiagnosed due to insufficient awareness. Among the various physiological processes influenced by opioids, alterations in blood glucose levels induced by opioids are a side effect that is commonly overlooked. The significance of this report lies in emphasizing the neglected association between opioids and hypoglycemia and highlighting the importance of close glucose monitoring to prevent hypoglycemic events in the perioperative setting.

PATIENT CONCERNS

An 89-year-old man with type 2 diabetes mellitus experienced acute severe hypoglycemic episode immediately after general anesthesia induction. Baseline blood glucose level before starting anesthesia induction was 4.0 mmol/L. However, it decreased substantially to 0.96 mmol/L immediately after anesthesia induction.

DIAGNOSIS

The patient exhibited normal serum insulin, C-peptide, and cortisol levels, alongside unremarkable renal and hepatic function. After excluding other causes of hypoglycemia, we speculate that opioids were the culprits due to the temporal association and the rapid decline in blood glucose levels.

INTERVENTIONS

Forty milliliters of 50% dextrose were administered intravenously followed by an infusion of 5% dextrose.

OUTCOMES

Recovery from anesthesia, extubation, and postoperative recovery were unremarkable. No further hypoglycemic episodes occurred during hospitalization.

LESSONS

A precipitous and rapid decline in blood glucose following anesthesia induction is extremely uncommon. When a clinical anesthesiologist detects an abnormally low bispectral index during general anesthesia, hypoglycemia should be suspected. Instituting glucose monitoring in these situations can enable a timely diagnosis, forestalling the onset of life-threatening severe hypoglycemia.

Evaluation of Prognosis of Coma Patients With Acute Brain Injury by Electroencephalogram Bispectral Index Monitoring

BACKGROUND

The high mortality rate of comatose patients with traumatic brain injury is a prominent public health issue that negatively impacts patients and their families. Objective, reliable tools are needed to guide treatment decisions and prioritize resources.

OBJECTIVE

This study aimed to evaluate the prognostic value of the bispectral index (BIS) in comatose patients with severe brain injury.

METHODS

This was a retrospective cohort study of 84 patients with severe brain injury and Glasgow Coma Scale (GCS) scores of 8 and less treated from January 2015 to June 2017. Sedatives were withheld at least 24 hr before BIS scoring. The BIS value, GCS scores, and Full Outline of UnResponsiveness (FOUR) were monitored hourly for 48 hr. Based on the Glasgow Outcome Scale (GOS) score, the patients were divided into poor (GOS score: 1-2) and good prognosis groups (GOS score: 3-5). The correlation between BIS and prognosis was analyzed by logistic regression, and the receiver operating characteristic curves were plotted.

RESULTS

The mean (SD) of the BIS value: 54.63 (11.76), p = .000; and GCS score: 5.76 (1.87), p = .000, were higher in the good prognosis group than in the poor prognosis group. Lower BIS values and GCS scores were correlated with poorer prognosis. Based on the area under the curve of receiver operating characteristic curves, the optimal diagnostic cutoff value of the BIS was 43.6, and the associated sensitivity and specificity were 85.4% and 74.4%, respectively.

CONCLUSION

Taken together, our study indicates that BIS had good predictive value on prognosis. These findings suggested that BIS could be used to evaluate the severity and prognosis of severe brain injury.

Endocrine emergencies in anesthesia

PURPOSE OF REVIEW

An increasing number of patients with endocrine disorders will present to the operating rooms. In this review, we outline the common endocrine disorders that the anesthesiologist may face in the perioperative time span, review the controversies in optimal management, as well as summarize the recent literature for the management of these complex patients.

RECENT FINDINGS

Perioperative management of pheochromocytoma and paraganglioma has been facilitated by improved medical management and the adoption of minimally invasive surgical techniques. An improved understanding of the sequelae of carcinoid syndrome has resulted in safer perioperative management. Perioperative glycemic management requires a fundamental understanding of perioperative fluid resuscitation and adverse events associated with the new generation oral hyperglycemic agents to prevent avoidable complications.

SUMMARY

Endocrine disorders will commonly present in the perioperative time period and the anesthesiologist plays a critical role in achieving good operative outcomes.

Potential Biochemical Mechanisms of Brain Injury in Diabetes Mellitus

The goal of this review was to summarize current biochemical mechanisms of and risk factors for diabetic brain injury. We mainly summarized mechanisms published in the past three years and focused on diabetes induced cognitive impairment, diabetes-linked Alzheimer’s disease, and diabetic stroke. We think there is a need to conduct further studies with increased sample sizes and prolonged period of follow-ups to clarify the effect of DM on brain dysfunction. Additionally, we also think that enhancing experimental reproducibility using animal models in conjunction with application of advanced devices should be considered when new experiments are designed. It is expected that further investigation of the underlying mechanisms of diabetic cognitive impairment will provide novel insights into therapeutic approaches for ameliorating diabetes-associated injury in the brain.

Electroencephalography: Clinical Applications During the Perioperative Period

Electroencephalography (EEG) monitoring has become technically feasible in daily clinical anesthesia practice. EEG is a sensitive method for detecting neurophysiological changes in the brain and represents an important frontier in the monitoring and treatment of patients in the perioperative period. In this review, we briefly introduce the essential principles of EEG. We review EEG application during anesthesia practice in the operating room, including the use of processed EEG in depth of anesthesia assessment, raw EEG monitoring in recognizing brain states under different anesthetic agents, the use of EEG in the prevention of perioperative neurocognitive disorders and detection of cerebral ischemia. We then discuss EEG utilization in the intensive care units, including the use of EEG in sedative level titration and prognostication of clinical outcomes. Existing literature provides insight into both the advances and challenges of the clinical applications of EEG. Future study is clearly needed to elucidate the precise EEG features that can reliably optimize perioperative care for individual patients.