Predictors of electrocerebral inactivity with deep hypothermia

Abstract

Objective Cooling to electrocerebral inactivity (ECI) by electroencephalography (EEG) remains the gold-standard to maximize cerebral and systemic organ protection during deep hypothermic circulatory arrest (DHCA). We sought to determine predictors of ECI to help guide cooling protocols when EEG monitoring is unavailable. Methods Between July 2005 and July 2011, 396 patients underwent thoracic aortic operation with DHCA; EEG monitoring was utilized in 325 (82%) of these cases to guide the cooling strategy and constituted the study cohort. EEG monitoring was utilized for all elective cases and when available for non-elective cases. Multivariable linear regression was used to assess predictors of the nasopharyngeal temperature and cooling time required to achieve ECI. Results Cooling to a nasopharyngeal temperature of 12.7°C or for a duration of 97 minutes was required to achieve ECI in > 95% of patients. Only 7% and 11% of patients achieved ECI by 18°C or 50 minutes of cooling, respectively. No independent predictors of nasopharyngeal temperature at ECI were identified. Independent predictors of cooling time included body surface area (+18 minutes/m2), white race (+7 minutes), and starting nasopharyngeal temperature (+3 minutes/°C). Low complication rates were observed (1.5% ischemic stroke, 1.5% permanent paraparesis/paraplegia, 2.2% new onset dialysis, and 4.3% 30 day/in-hospital mortality). Conclusion Cooling to a nasopharyngeal temperature of 12.7°C or for a duration of 97 minutes achieved ECI in > 95% of patients in our study population. However, patient-specific factors were poorly predictive of the temperature or cooling time required to achieve ECI, necessitating EEG monitoring for precise ECI detection.

The utility of the aortic dissection team: outcomes and insights after a decade of experience

“…Total arch replacement is similarly performed for aneurysm or extensive destruction of the transverse arch. For hemi-or total arch repair, the open distal anastomosis is completed under a period of moderate hypothermic circulatory arrest (HCA) (28) with intraoperative electroencephalographic (EEG) monitoring, when available (29,30). In the unmonitored cases, patients are cooled until the nasopharyngeal temperature is <24 ℃ as prior work from our group has demonstrated that EEG findings suggestive of cerebral ischemia occur more frequently following onset of HCA at warmer temperatures (28).…”

Neuromonitoring in der Kardioanästhesie

“…bei der ein isoelektrisches EEG auftritt), unterschiedlich[55]. Beispielsweise schwanken die Angaben über die nasopharyngeale Temperatur, bei der ein isoelektrisches EEG einsetzt, zwischen 26 und 10°C[56,57]. Insgesamt kann das prozessierte EEG-Monitoring bei tiefer Hypothermie kaum zur Beurteilung einer adäquaten Narkosetiefe genutzt werden.…”

Antegrade versus retrograde cerebral perfusion for hemiarch replacement with deep hypothermic circulatory arrest: Does it matter? A propensity-matched analysis

“…A total of 358 cases (81.4%) were monitored, as previously described. 14,15 In brief, the patients were cooled until electrocerebral inactivity was reached, after which, DHCA was begun. Electrocerebral inactivity ensures maximal metabolic suppression of the brain and, therefore, maximal neurocerebral protection.…”