Jeffrey J. Stanley

Attenuation of renal reperfusion injury in rats by the 21-aminosteroid U74006F☆☆☆

PURPOSE The 21-aminosteroids represent a new class of compounds that serve as potent inhibitors of iron-dependent lipid peroxidation, the latter being an important component of ischemia-reperfusion tissue injury. It is hypothesized that reperfusion injury accompanies renal ischemia, and postischemic administration of one of these steroids, U74006F, will reduce renal damage in a rodent model, as assessed by renal function (plasma creatinine), histologic evidence of renal injury, and animal survival during a 72-hour interval. METHODS Fifty-one rats subjected to 45 minutes of renal ischemia were treated on clamp release with 3 or 10 mg/kg U74006F intravenously (n = 5 and 19, respectively), an inactive vehicle (n = 23), or sham operation (n = 4). RESULTS Both doses of U74006F improved morphologic outcome compared with vehicle-treated animals. Statistically significant improvement in renal function was observed with the 10 mg/kg dose of U74006F (p = 0.029, 0.014, and 0.065 at 24, 48, and 72 hours, respectively) but not with the 3 mg/kg dose. Only one (5.2%) of 19 rats receiving high-dose U74006F (10 mg/kg) died within 72 hours after ischemia, compared with five deaths (29.4%) in 17 rats receiving citrate vehicle alone (p = 0.060). All sham-operated animals survived 72 hours with normal morphology and plasma creatinine levels. CONCLUSION These data suggest that iron-dependent lipid peroxidation is a component of reperfusion injury and indicate that U74006F may be useful in reducing this form of renal ischemic damage.

Minimal physiologic temperature variations during renal ischemia alter functional and morphologic outcome

Aortic and renal vascular reconstruction often involve significant renal ischemia. Profound hypothermia during renal ischemia preserves renal tissue. However, in the clinical setting of vascular reconstruction specific attempts at cooling the kidney are often impractical, and renal ischemia frequently occurs at physiologic temperatures. This study demonstrates that minimal temperature changes during renal ischemia alter the functional and morphologic outcome. Rats anesthetized with halothane underwent a right nephrectomy and placement of a snare around the left renal pedicle for 45 minutes to produce renal ischemia. Seventy-five adult male Sprague-Dawley rats, weighing 250 to 350 gm were divided into three groups based on the body temperature maintained during renal ischemia (35 degrees C, 37 degrees C, 39 degrees C). Body temperature was continuously monitored with a rectal thermistor and maintained by adjustment of a heating pad and lamp. Two postischemic protocols were followed including a creatinine assessment protocol with blood samples collected at 24, 48, and 72 hours and a histologic assessment protocol with biopsy of the kidney at 30 hours. At 24 hours after ischemia plasma creatinine concentrations were increased in rats with elevated body temperatures (35 degrees C vs 37 degrees C; [p = 0.001], 37 degrees C vs 39 degrees C; [p = 0.150]). The 30-hour histologic assessment indicated a difference in morphologic outcome (35 degrees C vs 37 degrees C; [p = 0.063], 37 degrees C vs 39 degrees C; [p = 0.016]), with proximal tubular morphology being better maintained at lower temperatures.(ABSTRACT TRUNCATED AT 250 WORDS)

Trends in otolaryngology residency training in the surgical treatment of obstructive sleep apnea

Most patients with obstructive sleep apnea (OSA) have multilevel obstruction. Improved outcomes with multilevel surgery compared to isolated palatal surgery have been well documented. Despite this, surgical practice patterns in the United States have been slow to change. The purpose of this study was to evaluate whether current practice patterns are a reflection of limited surgical residency training in hypopharyngeal procedures.

End-tidal carbon dioxide measurement during pediatric polysomnography: Signal quality, association with apnea severity, and prediction of neurobehavioral outcomes

STUDY OBJECTIVES To identify the role of end-tidal carbon dioxide (EtCO2) monitoring during polysomnography in evaluation of children with obstructive sleep apnea syndrome (OSAS), including the correlation of EtCO2 with other measures of OSAS and prediction of changes in cognition and behavior after adenotonsillectomy. DESIGN Analysis of screening and endpoint data from the Childhood Adenotonsillectomy Trial, a randomized, controlled, multicenter study comparing early adenotonsillectomy (eAT) to watchful waiting/supportive care (WWSC) in children with OSAS. SETTING Multisite clinical referral settings. PARTICIPANTS Children, ages 5.0 to 9.9 y with suspected sleep apnea. INTERVENTIONS eAT or WWSC. MEASUREMENTS AND RESULTS Quality EtCO2 waveforms were present for ≥ 75% of total sleep time (TST) in 876 of 960 (91.3%) screening polysomnograms. Among the 322 children who were randomized, 55 (17%) met pediatric criteria for hypoventilation. The mean TST with EtCO2 > 50 mmHg was modestly correlated with apnea-hypopnea index (AHI) (r = 0.33; P < 0.0001) and with oxygen saturation ≤ 92% (r = 0.26; P < 0.0001). After adjusting for AHI, obesity, and other factors, EtCO2 > 50 mmHg was higher in African American children than others. The TST with EtCO2 > 50 mmHg decreased significantly more after eAT than WWSC. In adjusted analyses, baseline TST with EtCO2 > 50 mmHg did not predict postoperative changes in cognitive and behavioral measurements. CONCLUSIONS Among children with suspected obstructive sleep apnea syndrome, overnight end-tidal carbon dioxide (EtCO2) levels are weakly to modestly correlated with other polysomnographic indices and therefore provide independent information on hypoventilation. EtCO2 levels improve with adenotonsillectomy but are not as responsive as AHI and do not provide independent prediction of cognitive or behavioral response to surgery. CLINICAL TRIAL REGISTRATION Childhood Adenotonsillectomy Study for Children with OSAS (CHAT). ClinicalTrials.gov Identifier #NCT00560859.

Friedman tongue position and cone beam computed tomography in patients with obstructive sleep apnea

Evaluate the correlation between Friedman Tongue Position (FTP) and airway cephalometrics in patients with obstructive sleep apnea (OSA).