Accuracy of identifying the cricothyroid membrane by anesthesia trainees and staff in a Canadian institution.

PURPOSE: We sought to determine the rate of successful identification of the cricothyroid membrane by anesthesia residents and staff at a Canadian institution. METHODS: In this prospective study, healthy adult volunteer subjects were positioned supine with their necks placed in neutral position. There were 12 subjects, half of whom were non-obese (body mass index < 30.0 kg·m(2)) and half of whom were obese. There were equal numbers of male and female subjects in each of the obese and non-obese groups. Anesthesia staff and resident participants were allowed to palpate multiple subjects but with only one attempt per subject. For each subject, ultrasonography was used to identify the superior and inferior borders of the cricothyroid membrane, which were then marked with "invisible" ink that could be made visible with ultraviolet light. The midline was also marked with invisible ink. Identification of the cricothyroid membrane was considered correct if the mark was between the superior and inferior borders and within 0.5 cm of the midline. RESULTS: Altogether, 61 participants palpated 12 subjects, resulting in 186 identifications. The success rates for the subgroups were as follows: non-obese men 72% (95% confidence interval [CI] 59 to 85%); obese men 39% (95% CI 26 to 54%); non-obese women 24% (95% CI 12 to 36%); obese women 35% (95% CI 21 to 49%). CONCLUSION: Success rates for correct identification of the cricothyroid membrane were poor in this Canadian institution.

The Jonas study: evaluation of the retrievability of the Cordis OptEase inferior vena cava filter.

PURPOSE: To evaluate the success, safety, and efficacy of the retrieval of the OptEase Permanent/Retrievable Vena Cava Filter (Cordis, Warren, NJ), when implanted for temporary protection against venous thromboembolism. MATERIALS AND METHODS: This prospective, multicenter, non-randomized study enrolled 27 patients who needed temporary protection against pulmonary embolism in whom the intent at the time of filter insertion was retrieval of the OptEase filter. Patients presented with deep venous thrombosis (n = 17), pulmonary embolism (PE) (n = 6), and high risk for PE without thromboembolic disease (n = 4). Assessments included duplex sonography of the access site performed within 24 hours of device implantation and retrieval. All patients underwent cavography before and after filter placement and filter retrieval. Contrast-enhanced computed tomography (CT) of the abdomen and clinical follow-up was performed at 1 month after device retrieval. RESULTS: Of the 27 enrolled patients, 21 patients (77.8%) met the criteria for retrieval and all 21 patients (100%) had filters successfully retrieved with no associated adverse events. Retrieval was not attempted in six patients as a result of ongoing contraindication to anticoagulation (n = 3), large trapped thrombi within the filter (n = 2), and poor patient prognosis (n = 1). Time to retrieval ranged from 5 to 14 days with a mean implantation time of 11.1 days +/- 1.82. No symptomatic pulmonary embolism, vena cava wall injury, vena cava stenosis, significant bleeding, filter fracture, or filter migration was observed. Nineteen of the 21 patients (90.5%) were followed for 1-month post-retrieval with no device-related adverse events or symptomatic PE. Caval patency was documented in 18 of these 19 patients with CT. Two patients were lost to follow-up, and one patient refused to undergo CT examination. CONCLUSION: The OptEase permanent/retrievable vena cava filter can be safely and successfully retrieved up to 14 days in patients who no longer require inferior vena cava filter protection against pulmonary embolism.

Is routine micropuncture access necessary for percutaneous nephrostomy? A randomized trial.

OBJECTIVE: To compare the micropuncture technique and the conventional large-bore needle approach for renal access. METHODS: From July 1999 to July 2000, patients referred to interventional radiology for emergent or elective percutaneous nephrostomy with normal coagulation profiles were considered for the study. Nephrostomy procedures were performed using a micropuncture system or large-bore needle for collecting system access; 24 nephrostomy procedures were randomized to each group using permuted blocks and opaque sealed envelopes. Gross hematuria, quantitative urine red blood cell counts, pain scores and procedural success were compared between the 2 groups. RESULTS: There was a small difference in the incidence of gross hematuria between the large-bore needle and micropuncture groups (12 [50%] v. 8 [33%] patients), but this difference was not statistically significant. Quantitative urine red blood cell counts obtained immediately after and 24 hours after nephrostomy placement showed no significant differences. Significantly fewer needle passes were required for access in the large-bore needle group than the micropuncture group (1.7 v. 2.8, p = 0.01), and mean procedure duration was 7 minutes longer in the micropuncture group, although this difference was not significant. No differences in pain scores or procedure success were seen. CONCLUSION: Percutaneous nephrostomy performed with a micropuncture system in patients with normal coagulation profiles does not significantly decrease organ bleeding or pain. More needle passes and manipulations are required, which may increase procedure duration. The additional costs of routine micropuncture access for percutaneous nephrostomy are not supported by this study.