Effects of hypnosis on the relative parasympathetic tone assessed by ANI (Analgesia/Nociception Index) in healthy volunteers: a prospective observational study.

Hypnosis has shown an effect on the regulation of the autonomic nervous system by increasing parasympathetic activity. The Analgesia/Nociception Index (ANI) is derived from heart rate variability and represents the relative parasympathetic tone. We investigated the effects of hypnosis on ANI in healthy volunteers. Participants to the 2016 International Hypnosis congress, Saint Malo, France were recruited in this prospective observational study. After comfortable positioning of the subject in the sitting position (T0), the hypnotic trance was induced (T1) then conducted with suggestions of comfort (T2) before return to normal consciousness (T3). The ANI, heart rate (HR) and respiratory rate (RR) were recorded at the different time-points. Forty subjects were enrolled (31 women, 9 men). The mean ± SD ANI at T2 (84 ± 12) was significantly greater than at T0 (60 ± 10), T1 (62 ± 9) and T3 (59 ± 11). The median [25th-75th percentile] ANI values at T2 were significantly greater in women (90 [83-95]) than in men (74 [68-83]). There were no significant variations of HR during time. The median [25th-75th percentile] RR at T1 (16 [14-18] breaths/min) and T2 (14 [12-16] breaths/min) were significantly smaller than at T0 (18 [16-20] breaths/min) and T3 (18 [16-20] breaths/min). This study shows that hypnosis induces an increase in the relative parasympathetic tone assessed by ANI in healthy volunteers, with greater ANI values observed in women. These results suggest that ANI monitoring may provide an objective tool for the measurement of the intensity of the hypnotic process, although this should be confirmed by further studies.

[Autotransfusion during caesarean section with blood containing p salbutamol without adverse effects]. / Autotransfusion en cours de césarienne de sang contenant du salbutamol sans effets indésirables.

We report the case of a patient presenting with a placenta praevia and who donated autologous blood while she had beta 2-agonist tocolysis. As the restitution of blood containing salbutamol at therapeutic concentration may induce uterine atony and cardiovascular symptoms, we monitored maternal clinical signs and plasma concentrations of salbutamol when autologous blood was retransfused after the end of Caesarean section. The maternal plasma beta 2-agonist levels during tocolysis were in agreement with the usual therapeutic concentrations. The beta 2-agonist infusion was discontinued 30 minutes before the subarachnoid blockade and the blood concentration measured at the time of skin incision was below the therapeutic threshold. The retransfusion of autologous blood neither raised the salbutamol concentration above the therapeutic threshold value, nor induced any clinical symptoms. After Caesarean section the retransfusion of autologous blood containing therapeutic concentration of salbutamol seems to be innocuous.