Benefits and pitfalls of cadavers as learning tool for ultrasound-guided regional anesthesia

Abstract

Ultrasound-guided regional anesthesia (UGRA), like other basic skills, should be learnt in a simulation laboratory before performing on the patient. Cadavers provide an ideal tool for learning sonoanatomy and skills required for performing UGRA. On the basis of preservation technique used, the cadavers can be formalin embalmed cadavers, Thiel cadavers (soft cadavers), and fresh frozen cadavers. We compared three types of cadavers for performing ultrasound-guided upper and lower limb blocks. We observed that fresh frozen and Thiel cadavers were less smelling and had more realistic appearance as compared to formalin embalmed cadavers. It was seen that Thiel cadavers were more flexible and hence, rotation of neck, shoulder and knee was easier. Although images seen in most cadavers were comparable with live subjects but, Thiel cadavers provided more realistic model.

Intra and Inter-rater Reliability between Ultrasound Imaging and Caliper Measures to determine Spring Ligament Dimensions in Cadavers

“…In addition, MDC values for the SL dimensions, such as length (MDC US = 0.069 cm versus MDC Caliper = 0.083 cm), thickness (MDC US = 0 cm versus MDC Caliper = 0.021 cm) and width (MDC US = 0.013 cm versus MDC Caliper = 0 cm), showed that US measurements presented a higher absolute accuracy with lower MDC values than caliper measures for SL length and thickness dimensions, while caliper displayed greater absolute accuracy with lower MDC for SL width dimensions. According to MDC may be used as the change magnitude necessary to provide measuring confidence to be sure about these values are not the result secondary random variations or measurement errors 12 , these MDCs may be considered as cut-off reference values to determine SL dimensions modifications secondary to anatomic abnormalities 5–8 , ultrasound-guided invasive procedures 9 , and ligament injuries course after treatment 21,22 .…”

“…Sixty-two feet from formaldehyde-embalmed human cadavers, 8 males and 26 females, without presence of any type of trauma were recruited in our research protocol 9 . The mean (SD) age was 76.46 (6.46) years; range from 66 to 89 years old.…”

“…Several studies have evaluated this anatomic structure by ultrasound imaging (US) and caliper measurements in cadavers 5–8 , although prior investigations have not yet analyzed the reliability for measuring SL dimensions using caliper and US to determine the anatomic correlation of the SL in cadaveric feet. Thus, given that there is existing literature correlating ultrasound measurements to clinical decisions and other imaging modalities 5–8 , absolute accuracy of the measurement needs to be determined due to the lack of studies about reliability and correlation between caliper and US measurements of the SL in cadaveric feet addressing width, thickness and length for a better accuracy of these evaluations and the improvement of ultrasound-guided procedures 9 . Both intra and inter-rater reliability needs to be detailed in order to determine absolute accuracy and repeatability of these measurements within a same evaluator and between both evaluators by both US and caliper 10–13 .…”

The Utility of Color Doppler to Confirm Endotracheal Tube Placement: A Pilot Study

“…11 However, cadaver tissue often appears different from and lacks the respiratory variations of live human tissue with ultrasound imaging; thus, a cadaver model may not accurately reflect the performance of CDI in confirming ETT placement in live humans. 12,13 In this pilot study, we used video captured from live humans, with either tracheal or esophageal intubations, to evaluate whether CDI can improve correct ETT localization compared to grayscale US using an online assessment of medical professionals. We also investigated whether there is a relationship between the accuracy of US interpretation for this indication and the training level of participants.…”

“… 11 However, cadaver tissue often appears different from and lacks the respiratory variations of live human tissue with ultrasound imaging; thus, a cadaver model may not accurately reflect the performance of CDI in confirming ETT placement in live humans. 12 , 13 …”