Predictors of electrocerebral inactivity with deep hypothermia.

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 used in 325 (82%) of these patients to guide the cooling strategy, and constituted the study cohort. Electroencephalographic monitoring was used for all elective cases and, when available, for nonelective 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/m(2)), white race (7 minutes), and starting nasopharyngeal temperature (3 minutes/°C). Low complication rates were observed (ischemic stroke, 1.5%; permanent paraparesis/paraplegia, 1.5%; new-onset dialysis, 2.2%; and 30-day/in-hospital mortality, 4.3%). CONCLUSIONS: 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.

Venous line filtration: a novel technique for cases involving inferior vena caval and right atrial tumor and associated thrombus: a two-case series.

Two patients are presented with right atrial tumors, who were considered to be at risk for tumor thrombus migration down the venous line into the cardiopulmonary bypass (CPB) circuit during surgical excision, which may lead to compromised or interrupted venous drainage. An arterial line filter was placed in the venous line to capture any material that might become dislodged and embolize into the circuit. Vacuum-assisted venous drainage, at approximately -50 mmHg, was used to overcome any resistance caused by the filter in the venous line. In one case, tumor thrombus obstructed the filter, requiring the use of the bypass line around the filter, so venous return could be maintained. In both cases, thrombus was found in the filter. The first case was a 44-year-old female (81 kg, 137 cm, body surface area (BSA) 1.66 m2) who presented with a metastatic pheochromocytoma with associated thrombus arising from the left adrenal gland and extending into the inferior vena cava (IVC) and right atrium. The second case was a 37-year-old male (95 kg, 178 cm, BSA 2.17 m2), who presented with a very large angiosarcoma tumor involving almost the entire right atrium. We have shown that venous line filtration with vacuum-assisted venous drainage can be performed safely, and should be considered in cases where there is tumor thrombus in the vena cava or right atrium, which may threaten venous return.