Προγνωστικοί δείκτες διαταραχής του αυτόνομου νευρικού συστήματος κατά την περιοχική αναισθησία
Prognostic indices of autonomic nervous system disorder during regional anesthesia
Eelco de Bree
The reported incidence of cardiac arrest during spinal anesthesia is 6.4+1.2 per 10,000 patients. Many of these arrests occurred in healthy young patients during minor surgery. This raises the question of whether some of them were avoidable. We investigated the value of Heart Rate Variability (HRV) to identify patients susceptible to develop severe bradycardia during spinal anesthesia.
Eighty ASA I-II patients, 21-60 years of age, undergoing elective surgery under spinal anesthesia were studied. The HRV was assessed for 25 min before the spinal block. Two spectral components of HRV were calculated, a low frequency (LF) and a high frequency (HF) component. Patients were grouped according to whether bradycardia did or did not develop during spinal anesthesia.
Nineteen patients developed severe bradycardia (&λτ 45 bpm). The mean value of HF before spinal anesthesia was significantly increased in the bradycardic group (p΄&λτ 0.05). Correlation between baseline heart rate and minimum heart rate and LF, HF during spinal anesthesia was significant (p΄&λτ 0.01). A receiver operator curve characteristic analysis showed a sensitivity and specificity of HF and baseline heart rate of 65% and 74% respectively, to predict bradycardia ΄&λτ 45 bpm after spinal anesthesia.
The present study shows that HF and clinical factors such as patient’s baseline heart rate could identify patients prone to develop severe bradycardia during spinal anesthesia.