Primary failure of thoracic epidural analgesia: revisited.

Primary failure of thoracic epidural analgesia (TEA) remains an important clinical problem, whose incidence can exceed 20% in teaching centers. Since loss-of-resistance (LOR) constitutes the most popular method to identify the thoracic epidural space, the etiology of primary TEA failure can often be attributed to LOR's low specificity. Interspinous ligamentous cysts, non-fused ligamenta flava, paravertebral muscles, intermuscular planes, and thoracic paravertebral spaces can all result in non-epidural LORs. Fluoroscopy, epidural waveform analysis, electrical stimulation, and ultrasonography have been proposed as confirmatory modalities for LOR.The current evidence derived from randomized trials suggests that fluoroscopy, epidural waveform analysis, and possibly electrical stimulation, could decrease the primary TEA failure to 2%. In contrast, preprocedural ultrasound scanning provides no incremental benefit when compared with conventional LOR. In the hands of experienced operators, real-time ultrasound guidance of the epidural needle has been demonstrated to provide comparable efficacy and efficiency to fluoroscopy.Further research is required to determine the most cost-effective confirmatory modality as well as the best adjuncts for novice operators and for patients with challenging anatomy. Moreover, future trials should elucidate if fluoroscopy and electrical stimulation could potentially decrease the secondary failure rate of TEA, and if a combination of confirmatory modalities could outperform individual ones.

Visceral versus somatic pain: an educational review of anatomy and clinical implications.

Somatic and visceral nociceptive signals travel via different pathways to reach the spinal cord. Additionally, signals regulating visceral blood flow and gastrointestinal tract (GIT) motility travel via efferent sympathetic nerves. To offer optimal pain relief and increase GIT motility and blood flow, we should interfere with all these pathways. These include the afferent nerves that travel with the sympathetic trunks, the somatic fibers that innervate the abdominal wall and part of the parietal peritoneum, and the sympathetic efferent fibers. All somatic and visceral afferent neural and sympathetic efferent pathways are effectively blocked by appropriately placed segmental thoracic epidural blocks (TEBs), whereas well-placed truncal fascial plane blocks evidently do not consistently block the afferent visceral neural pathways nor the sympathetic efferent nerves. It is generally accepted that it would be beneficial to counter the effects of the stress response on the GIT, therefore most enhanced recovery after surgery protocols involve TEB. The TEB failure rate, however, can be high, enticing practitioners to resort to truncal fascial plane blocks. In this educational article, we discuss the differences between visceral and somatic pain, their management and the clinical implications of these differences.

Validation of age-based body mass estimation methods in toddlers and pre-school children

Background: Body mass is commonly used to determine medication dosages and equipment size. In emergency situations (including cases necessitating surgery) weighing paediatric patients can be impractical. Clinicians may use any of several body mass estimation techniques to surmount this obstacle. This study's aim was to compare the actual body mass of children with estimated mass as predicted by several commonly used estimation methods. Methods: This diagnostic cross-sectional study recorded data from patients between one and five years of age in the Tshwane district. Measurement procedures were standardised to ensure consistency. Results: The relationship between anthropometric and demographic variables were determined and applied to different estimation models to assess the models' applicability to the Tshwane district population. The APLS (Advanced Paediatric Life Support) formula (Body mass (kg) = (Age + 4) × 2) proved the most appropriate. This formula gave a mean underestimation of 0.51 kg. Age proved to be the variable with the strongest correlation to body mass. A formula was developed specifically for the selected population, adding mid upper arm circumference as a second variable. This formula is more complex and offers only a marginal improvement in accuracy of weight estimation. Conclusion: The APLS formula is a reasonable tool to use when estimating the body mass in children between one and five years old in the Tshwane district population. It is a well-known and simple formula, making it well suited to this purpose