Evaluation of distal radial artery cross-sectional internal diameter in pediatric patients using ultrasound.

In this study, we measure the radial artery internal diameter (RAID) in children up to 4 years of age before and after the induction of anesthesia. A B-mode portable color Doppler ultrasound was used to measure the RAID. Three sets of measurements were taken for each child before and after the induction of anesthesia and with the wrist in the neutral and dorsiflexed positions. The reliability of the mean value of the RAID in the three sets in 24 patients was established. There were discrepancies between the RAID and the proposed catheter size in some individuals, which may not only render placement difficult but also have potential for arterial injury. There are good reasons to measure the RAID in small children prior to insertion of an intra-arterial catheter.

Ultrasound assessment of the vertebral level of the intercristal line in pregnancy.

BACKGROUND: The intercristal line is known to most frequently cross the L4 spinous process or L4-5 interspace; however, it is speculated to be positioned higher during pregnancy because of the exaggerated lumbar lordosis. Clinical estimation of vertebral levels relying on the use of the intercristal line has been shown to often be inaccurate. We hypothesized that the vertebral level of the intercristal line determined by palpation would be higher than the level determined by ultrasound in pregnant women. METHODS: Fifty-one term pregnant patients were recruited. Two experienced anesthesiologists performed estimates of the position of the intercristal line by palpation. Using ultrasound, another anesthesiologist who was blinded to the clinical estimates, determined the position of the superior border of the iliac crest in the transverse and longitudinal planes and then identified the lumbar vertebral levels. The vertebral level at which the clinical estimates of the intercristal line crossed the spine was recorded and compared with the ultrasound-determined level of the superior border of the iliac crest. RESULTS: The clinical estimates of the spinal level of the intercristal line agreed with the ultrasound measurement 14% of the time (14 of 101; 95% confidence interval [CI]: 8%, 22%). The clinical estimates were 1 level higher than the ultrasound measurement 23% of the time (23 of 101; 95% CI: 16%, 32%) and >1 level higher 25% of the time (25 of 101; 1-tailed 95% CI: >18%). The distribution of the clinical estimates found clinicians locating the intercristal line at L3 or L3-4 54% of the time (54 of 101; 95% CI: 44%, 63%) and at L2-3 or higher 27% of the time (27 of 101; 1-tailed 95% CI: >20%). CONCLUSION: The anatomical position of the intercristal line was at L3 or higher in at least 6% of term pregnant patients using ultrasound. Clinical estimates were found to be ≥1 vertebral level higher than the anatomical position determined by ultrasound at least 40% of the time. This disparity may contribute to misidentification of lumbar interspaces and increased risk of neurologic injury during neuraxial anesthesia.

Radiostethoscopes: an innovative solution for auscultation while wearing protective gear.

OBJECTIVE: To demonstrate a radiostethoscope that could be modified and successfully used while wearing protective gear to solve the problem of auscultation in a hazardous material or infectious disease setting. DESIGN: This study was a randomized, prospective, and blinded investigation. SETTING: The study was conducted at the University of Miami-Jackson Memorial Hospital Center for Patient Safety. PARTICIPANTS: Two blinded anesthesiologists using a radiostethoscope performed a total of 100 assessments (50 each) to evaluate endotracheal tube position on a human patient simulator (HPS). INTERVENTIONS: Each lung of the HPS was ventilated separately using a double lumen tube. Four ventilation patterns (ie, right lung ventilation only; left lung ventilation only; ventilation of both lungs; and an esophageal intubation or no breath sounds) were simulated. The ventilation pattern was determined randomly and participants were blinded. An Ambu-Bag was used for ventilation. An assistant moved the radiostethoscope to the right and left lung fields and then to the abdomen of the HPS while ventilating. Subjects had to identify the ventilation pattern after listening to all three locations. A third member of the research team collected responses. Each subject, who wore both types of respirator (positive and negative), performed a total of 25 trials. Participants later compared the two types of respirators and their ability to auscultate for breath sounds. RESULTS: Subjects were able to verify the correct ventilation pattern in all attempts (100 percent). CONCLUSIONS: Radiostethoscopes appear to provide a viable solution for the problem of patient auscultation while wearing protective gear.