At caesarean section under regional anaesthesia, it is essential to test sensory block with light touch before allowing surgery to start

Evaluation of the accuracy of vibration sense with VibraTip™ as a tool to determine the level of anesthesia following subarachnoid block and its correlation with the pinprick sensation

BACKGROUND AND AIMS

Assessment of level of anesthesia after subarachnoid block (SAB) is essential. We aimed to evaluate the efficacy of vibration sense as a criteria to determine the level of surgical anesthesia.

METHOD AND MATERIALS

The study included patients, scheduled for various surgeries under SAB. The baseline values of vibration sense perception using VibraTip™, motor power using the modified Bromage scale, and sensory block by pinprick method were recorded preoperatively and at 5 and 7 min after administration of SAB. The correlation between vibration sense, loss of pinprick sensation, and level of anesthesia were assessed.

RESULTS

The concordance correlation coefficient between the pinprick and vibration sense at 5 min and 7 min showed poor strength of agreement with Pearson ρ (precision) being 0.4192 at 5 min and 0.4701 at 7 min.

CONCLUSION

Vibration sense serves as a reliable indicator to assess the level of surgical anesthesia following SAB. Vibration sense testing with VibraTip™along with motor power assessment can be used as a tool for assessment of level of block. There is a poor correlation between level of vibration sense and pinprick.

Algorithm for the anesthetic management of cesarean delivery in patients with unsatisfactory labor epidural analgesia

The management of a patient presenting with unsatisfactory labor epidural analgesia poses a severe challenge for the anesthetist wanting to provide safe anesthetic care for a cesarean delivery. Early recognition of unsatisfactory labor analgesia allows for replacement of the epidural catheter. The decision to convert labor epidural analgesia to anesthesia for cesarean delivery is based on the urgency of the cesarean delivery, airway examination, and the existence of a residual sensory and motor block.  We suggest an algorithm which is implemented in our department, based on the urgency of the cesarean delivery.

A randomized, observer-blind comparison between the Neurotip mounted Neuropen and a disposable plastic neurological wheel for assessing the level of spinal blockade at cesarean section

BACKGROUND

Various methods are used to assess the height of sensory block to touch under spinal anesthesia for cesarean section. We tested a novel, inexpensive, miniature, user-dependent plastic neurological wheel against the user-independent Neurotip mounted Neuropen.

METHODS

Patients received either spinal or combined spinal-epidural anesthesia. For each patient assessment, the devices were randomly assigned to one of two independent investigators. The order of device application was randomly permuted. Neither researcher was involved with anesthetic care. At 5-min intervals for 20 min after spinal injection, and again at the end of the operation, the levels of block to loss-of-touch sensation were assessed. While one investigator evaluated the block, the other left the operating room and vice versa. Mixed-effects regression and Bland-Altman analysis were used to weigh agreement between devices.

RESULTS

The mean difference in level-to-touch was 0.04 (95% CI -0.18, 0.27) dermatome levels. Measurement error standard deviation associated with the Neurotip mounted Neuropen and plastic neurological wheel was 1.36 (95% CI 1.26, 1.41) and 1.33 (95% CI 1.26, 1.46) dermatome levels, respectively. The difference in measurement error standard deviation was -0.03 (95% CI -0.16, 0.24). This evidence excludes the possibility, with 95% confidence, of clinically significant bias or measurement error differences between methods. Occasional wide variances in dermatome level were observed with both instruments at the initial assessment only.

CONCLUSION

The compact plastic neurological wheel is as clinically reliable as the Neurotip mounted Neuropen.

Assessment of block height for satisfactory spinal anaesthesia for caesarean section

We investigated block heights that anaesthetists considered adequate for caesarean section to proceed under spinal anaesthesia. During 3 months, 15 obstetric anaesthetists recorded block height to touch, pinprick or cold when spinal anaesthesia was considered satisfactory for caesarean section to proceed. Median (IQR [range]) block height for touch, pinprick, first cold and icy were: T10 (T7-T12 [T3-L1]); T5 (T4-T6 [C7-L1]); T5 (T4-T6 [C7-L1]); and T3 (T2-T4 [C7-L1]), respectively. Modalities were significantly correlated for: touch and cold, p = 0.0001; touch and icy, p = 0.0007; touch and pinprick, p = 0.0018; cold and icy, p < 0.0001; cold and pinprick, p = 0.0001; icy and pinprick, p < 0.0001. Pairwise comparisons showed differences between all modalities (p < 0.001) apart from pinprick and first cold (p = 0.94). All women had satisfactory anaesthesia despite 76 (81%) having a block to touch below T6. Single modality assessment of block height, particularly using touch, may erroneously indicate inadequate anaesthesia for caesarean section.

A prospective audit of regional anaesthesia failure in 5080 Caesarean sections

Anaesthesia for Caesarean section was audited over a 5 year period: 5080 cases were performed using spinal 63%, epidural top-up 26%, combined spinal-epidural 5% and primary general anaesthesia 5%. The rate of general anaesthesia conversion of regional anaesthesia was 0.8% for elective and 4.9% for emergency Caesarean section compared to Royal College of Anaesthetists targets of 1% and 3%. The rate of conversion of regional to general anaesthesia in category 1 Caesarean section was 20%. A total of 8% of women had general anaesthesia when both primary general and conversion of regional anaesthesia were combined. The rate of failure to achieve a pain-free operation was 6% with spinals, 24% with epidural top-up and 18% with combined spinal-epidural. Besides the type of anaesthesia and operative urgency, other factors associated with pre-operative failure of regional anaesthesia included body mass index, no previous Caesareans, and indication for Caesarean of acute fetal distress or maternal medical condition. Inadequacy of pre-operative anaesthetic block and duration of surgery were important risk factors for intra-operative failure. For spinal anaesthesia, use of a spinal opioid was associated with less pre-operative failure. For epidural top-up anaesthesia, lower epidural top-up volume was associated with less pre-operative failure, and use of adrenaline was associated with both less pre-operative and intra-operative failure. The rate of serious adverse incidents was 1 : 126 with general anaesthesia and 1 : 501 with regional anaesthesia.