Accuracy of 2-Phase Parathyroid CT for the Preoperative Localization of Parathyroid Adenomas in Primary Hyperparathyroidism.

BACKGROUND AND PURPOSE: Minimally invasive parathyroidectomy requires accurate preoperative localization of suspected adenomas, and multiphase CT allows adenoma characterization while providing detailed anatomic information. The purpose of this study was to assess the feasibility of a protocol using only arterial and venous phases to localize pathologic glands in patients with primary hyperparathyroidism. MATERIALS AND METHODS: We identified 278 patients with primary hyperparathyroidism who had undergone 2-phase CT with surgical cure. All scans were read prospectively by board-certified neuroradiologists. A neuroradiology fellow retrospectively reviewed images and reports and classified suspected adenomas on the basis of anatomic location. Accuracy was determined by comparing imaging results with surgical findings. The ability of 2-phase CT to localize adenomas to 1 of 4 neck quadrants and lateralize them to the correct side was assessed. Accuracy of identifying multigland disease was also evaluated. RESULTS: In patients with single-gland disease, the sensitivity and specificity of 2-phase CT to correctly localize the quadrant were 55.4% and 85.9%, respectively. The sensitivity and specificity of correct lateralization were 78.8% and 67.8%, respectively. The sensitivity and specificity to identify multigland disease were 22.9% and 79.5%, respectively. CONCLUSIONS: While the 2-phase CT protocol in this study demonstrates lower accuracy compared with reports of other techniques, its lower radiation compared with 3- and 4-phase techniques may make it a feasible alternative for preoperative parathyroid localization. Further prospective studies are needed to identify patients for whom this technique is most suitable.

Evaluation of academic and community surgery clerkships at a Midwestern medical school.

BACKGROUND: The equivalency of surgical clerkship experience between academic and community sites is an issue that is assessed with difficulty. We examined the objective performance of 222 medical students after completion of the 8-week surgical clerkship. Six different consecutive semesters were analyzed. There were two objective examinations reviewed, the National Board of Medical Examiners' subject examination and the surgical subportion of the Objective Structured Clinical Examination (OSCE) given at the end of the third year. METHODS: Medical students were classified into three separate groups based on the site of their surgical clerkship. The medical students were in either academic (100), community (79), or combined (academic and community) (43) locations. Medical student performance on the subject examination and OSCE was examined after completion of the general surgical clerkship. Single-factor analysis of variance testing was done to compare each of the three groups with respect to subject examination test score, or OSCE score. Significance was defined as P < 0.05. RESULTS: The combined group scored highest on the subject examination (73.6%). The community group scored highest on the OSCE (80.7%). However, no statistical significance exists between the three groups with regard to subject examination (P = NS) or OSCE (P= NS). Subject examination scores did not correlate with OSCE scores (r = 0.095). Objective measurements of surgical subject examination and OSCE were not statistically different between academic, community, and academic and community surgical clerkship participants. CONCLUSIONS: No statistically significant differences exist between the three groups with regards to OSCE failure rates, but the small amount of failures may have caused Type 2 error. Surgical clinical skills as tested by an OSCE and surgical knowledge as tested by a subject examination are equally attained by an academic or community surgical clerkship.

Differences in arterial and mixed venous IL-6 levels: the lungs as a source of cytokine storm in sepsis.

BACKGROUND: Several investigators have shown that blood levels of interleukin 6 (IL-6) correlate with the severity of illness in critically ill or injured patients. However, little is known about differential arterial and venous blood levels of the cytokine, especially across the lungs. METHODS: We measured differences in IL-6 levels in pulmonary and systemic arterial blood and then documented the production or elimination of IL-6 by the lungs in 19 patients with severe illness. Prospective data were obtained from multiple, simultaneous systemic arterial (ART) and mixed venous (MV) blood samples that were drawn for IL-6 analysis from systemic arterial and pulmonary artery catheters in 7 patients awaiting vascular operation and in 12 trauma patients being treated in the intensive care unit. RESULTS: A lung disorder was present in 5 patients (pneumonia [n = 1], lung trauma [n = 4]) and absent in the remaining 14 patients. The following data were obtained (mean +/- SD) from the highest MV IL-6 levels (pg/mL) in each patient. In patients with a lung disorder (n = 5) compared with those with no disorder (n = 14), ART IL-6 was 9309 +/- 12,521 versus 134 +/- 128 (P =.010), MV IL-6 was 5516 +/- 7420 versus 137 +/- 129 (P =.011), the absolute difference was 3793 +/- 5271 versus -3 +/- 15 (P =.011), and the percentage difference was 37.4% +/- 29.8% versus 1.5% +/- 12.3% (P =.001). The ART and MV IL-6 levels tended to be much higher in the 5 patients with pneumonia (n = 1) and lung injuries (n = 4) than in the patients without apparent pulmonary problems. In addition, the patients with a primary lung disorder demonstrated a net increase in IL-6 levels across the lungs, whereas there was no increase, but rather, a net reduction of IL-6 levels across the lungs in patients without a lung disorder. CONCLUSIONS: The lung appears to be a major producer of IL-6 in patients with an inflammatory lung process. There is a 39% increase in the level of IL-6 as it passes through inflamed lung, producing a marked difference in ART and MV IL-6 levels. Normal lung demonstrated little effect on either ART or MV IL-6 levels.

Incidence of pneumothorax from intercostal nerve block for analgesia in rib fractures.

BACKGROUND: The incidence of pneumothorax (PTX) after individual intercostal nerve block (INB) for postoperative pain reportedly varies from 0.073% to 19%.1-3 This study investigated the incidence of PTX after INB for rib fractures. METHODS: We conducted a retrospective chart review of patients admitted between January 1996 and December 1999 with rib fractures who received INB. RESULTS: One hundred sixty-one patients received 249 intercostal nerve block procedures (INBPs). An INBP is one session where a set of intercostal nerves are blocked. A total of 1,020 individual intercostal nerves were blocked. There were 14 pneumothoraces. The overall incidence of PTX per patient was 8.7%, with an incidence of PTX per INBP of 5.6%. The incidence of PTX was 1.4% for each individual intercostal nerve blocked. CONCLUSION: The incidence of PTX per individual intercostal nerve blocked is low. INB is an effective form of analgesia, and for most patients with rib fractures one INBP is sufficient to allow adequate respiratory exercises and discharge from the hospital.

Factors affecting mortality rates in patients with abdominal vascular injuries.

BACKGROUND: Major vessel injury is seen in 5% to 25% of patients admitted to hospitals with abdominal trauma, and this is the most common cause of death in these patients. METHODS: Data on 470 patients with abdominal vascular injuries seen at a Level I trauma center were reviewed retrospectively. RESULTS: The overall mortality rate was 45%. The incidence of various types of trauma were blunt in 51 patients (11%), gunshot wounds in 329 patients (70%), shotgun wounds in 21 patients (4%), and stab wounds in 69 patients (15%). The three vessels with the highest mortality rates were aorta (at and proximal to the renals) (32 of 35 [91%]), hepatic veins and/or retrohepatic vena cava (36 of 41 [88%]), and portal vein (25 of 36 [69%]). The most significant risk factors (p < 0.001) for death were a trauma score of 9 or less, initial operating room (OR) systolic blood pressure (SBP) < 90 mm Hg, final OR core temperature < 34 degrees C, 10 or more blood transfusions in the first 24 hours, and an initial emergency department SBP < 70 mm Hg. Of 120 patients with an initial OR SBP < 70 mm Hg, 103 (86%) died. Of 29 patients with a good response to a prelaparotomy thoracotomy with thoracic aortic cross-clamping (SBP > 90 mm Hg within 5 minutes), 11 (38%) survived. Of the remaining 87 patients, only 6 (7%) survived (p = 0.01). CONCLUSION: Rapid control of bleeding sites (to keep blood transfusions to < 10 units) and urgent correction of hypothermia seem to be the main factors improving survival over which the surgeon has some control.