Nomograms of Iranian fetal middle cerebral artery Doppler waveforms and uniformity of their pattern with other populations' nomograms

<p>Abstract</p> <p>Background</p> <p>Doppler flow velocity waveform analysis of fetal vessels is one of the main methods for evaluating fetus health before labor. Doppler waves of middle cerebral artery (MCA) can predict most of the at risk fetuses in high risk pregnancies. In this study, we tried to obtain normal values and their nomograms during pregnancy for Doppler flow velocity indices of MCA in 20 – 40 weeks of normal pregnancies in Iranian population and compare their pattern with other countries' nomograms.</p> <p>Methods</p> <p>During present descriptive cross-sectional study, 1037 normal pregnant women with 20^th–40^thweek gestational age were underwent MCA Doppler study. All cases were studied by gray scale ultrasonography initially and Doppler of MCA afterward. Resistive Index (RI), Pulsative Index (PI), Systolic/Diastolic ratio (S/D ratio), and Peak Systolic Velocity (PSV) values of MCA were determined for all of the subjects.</p> <p>Results</p> <p>Results of present study showed that RI, PI, S/D ratio values of MCA decreased with parabolic pattern and PSV value increased with simple pattern, as gestational age progressed. These changes were statistically significant (P = 0.000 for all of indices) and more characteristic during late weeks of pregnancy.</p> <p>Conclusion</p> <p>Values of RI, PI and S/D ratio indices reduced toward the end of pregnancy, but PSV increased. Despite the trivial difference, nomograms of various Doppler indices in present study have similar pattern with other studies.</p

Laryngeal Ultrasonography Versus Cuff Leak Test in Predicting Postextubation Stridor

Introduction: Although cuff leak test has been proposed as a simple method of predicting the occurrence of postextubation stridor, cut-off point of cuff-leak volume substantially differs between previous studies. In addition, laryngeal ultrasonography including measurement of air column width could predict postextubation stridor. The aim of the present study was to evaluate the value of laryngeal ultrasonography versus cuff leak test in predicting postextubation stridor.Methods: In a prospective study, all patients intubated for a minimum of 24 h for acute respiratory failure, airway protection and other causes were included. Patients were evaluated for postextubation stridor and need for reintubation after extubation. The cuff leak volume was defined as a difference between expiratory tidal volumes with the cuff inflated and deflated. Laryngeal air column width was defined as the width of air passed through the vocal cords as determined by laryngeal ultrasonography. The air-column width difference was the width difference between balloon-cuff inflation and deflation.Results: Forty one intubated patients with the mean age of 57.16±20.07 years were included. Postextubation stridor was observed in 4 patients (9.75%). Cuff leak test (cut off point: 249 mL) showed sensitivity and specificity of 75% and 59%, respectively. In addition, laryngeal ultrasonography (cut off point for air column width: 10.95 mm) resulted in sensitivity and specificity of 50% and 54%, respectively. Positive predictive value of both methods were <20%.Conclusion: Both cuff leak test and laryngeal ultrasonography have low positive predictive value and sensitivity in predicting postextubation stridor and should be used with caution in this regard