The effects of lidocaine on cardiac parasympathetic control in normal subjects and in subjects after myocardial infarction

Can local infiltration of lidocaine reduce the postoperative atrial fibrillation rate in patients undergoing lobectomy for lung cancer?

Background: Postoperative atrial fibrillation (POAF) occurs frequently after lung cancer surgery. Unfortunately, owing to the multifactorial etiology of POAF, no single drug or intervention can prevent POAF in all cases. The effects of local interventions after lung cancer surgery are unknown. This study investigated the effects of local infiltration of an anesthetic (lidocaine) on the post-lobectomy POAF rate.Methods: This non-randomized study included 81 patients who underwent lobectomy for lung cancer. Patients were divided into a lidocaine-infiltration group comprising patients who received lidocaine infiltration around the pulmonary veins and a no-intervention group. Patients were monitored for the development of POAF during hospitalization. Pre- and postoperative demographic and clinical data were analyzed.Results: AF occurred in 3 (7.5%) of 40 patients in the lidocaine-infiltration group and in 10 (24.39%) of 41 patients in the standard surgical resection group. Overall, it was observed that intraoperative lidocaine infiltration resulted in a lower POAF rate (p < .05).Conclusion: Local infiltration of lidocaine around the pulmonary veins in patients undergoing lobectomy for lung cancer was associated with a lower incidence of POAF, which is attributable to the local anesthetic and autonomic effects of lidocaine.

Bone Marrow Aspiration Does Not Induce a Measurable Pain Response Compared to Sham Procedure

Bone marrow is commonly collected from horses for regenerative medicine applications. Little information is available regarding pain experienced by the horse during bone marrow aspiration. The objective of this study was to characterize horse reaction and pain response during bone marrow aspiration (BMA) compared to a sham (SHAM) procedure. We hypothesized there would be significantly greater horse reaction or pain response measured by salivary cortisol, heart rate variability, and depth and duration of sedation between BMA and SHAM. Twelve university owned horses underwent a BMA and sham procedure, 4 weeks apart in a randomized cross-over design, while sedated with 0.4 mg/kg xylazine hydrochloride. As measures of sedation depth, head height was recorded and sedation level was scored at specific procedural time points. Salivary cortisol was measured immediately before and 2 h after each procedure. Heart rate variability was assessed before, during, and after each procedure. There were no differences in head height, sedation score, or salivary cortisol between groups. No differences were noted between groups in heart rate variability before or during the procedure, but there was a significant decrease in low frequency/high frequency (LF/HF) ratio after the procedure in the BMA group. Over time, there was a significant reduction in LF/HF ratio during the procedure in both groups. Overall, BMA from the sternum did not result in a measurable pain response during, or in the 2 h following the procedure, in comparison to a sham procedure.

The Effects of Cervical and Lumbar Epidural Anesthesia on Heart Rate Variability and Spontaneous Sequence Baroreflex Sensitivity

A high level of neuroaxial block may produce profound bradycardia and hypotension, possibly as a result of an imbalance between sympathetic and parasympathetic control of heart rate. We designed this study to test the hypothesis that cervical epidural anesthesia would increase the high-frequency (HF) component of heart rate variability (HRV) as a result of cardiac sympathectomy, whereas lumbar epidural anesthesia would cause sympathetic predominance. HRV and spontaneous baroreflex (SBR) sensitivity were assessed before and after cervical and lumbar epidural anesthesia by using plain 1.5% lidocaine (median upper/lower sensory block: C3/T8 for cervical and T11/L5 for lumbar) in healthy patients (n = 10 each). Electrocardiogram and noninvasive beat-to-beat arterial blood pressure were monitored. HRV was analyzed by using fast Fourier transformation. Least-square regression analysis relating R-R interval and systolic blood pressure during spontaneous fluctuation was performed to obtain SBR sensitivities. Cervical epidural group patients were significantly older (P < 0.01) and taller (P < 0.01). Cervical epidural anesthesia attenuated HF (0.15-0.4 Hz) and low-frequency (0.04-0.15 Hz) power of HRV with concomitant reductions in up- and down-sequence SBR sensitivities, suggesting decreased vagal modulation of heart rate. Lumbar epidural anesthesia resulted in a significant increase in the low-frequency/HF ratio of HRV and unchanged SBR indices, suggesting sympathetic predominance. HF power correlated well with SBR sensitivities under most of our study conditions. Respiratory rates and Paco(2) were unchanged by either epidural technique. Our results indicate that cervical, but not lumbar, epidural anesthesia depresses phasic and tonic dynamic modulation of the cardiac cycle by the vagal nerve in conscious humans.