Congenital high airway obstruction syndrome (CHAOS): Natural history,prenatal management strategies,and outcomes at a single comprehensive fetal center

PurposeCongenital high airway obstruction syndrome (CHAOS) is a devastating fetal condition of complete airway discontinuity resulting in significant hydrops and extreme lung hyperplasia. It is universally fatal with survival reported only in the rare spontaneous fistulization or EXIT intervention (Ex Utero Intrapartum Treatment). Even in these cases, mortality remains high, and current investigations are targeting prenatal interventions. This report describes our experience with management and fetal interventions for CHAOS, including laser laryngotomy.MethodsWe retrospectively reviewed all patients diagnosed with CHAOS at a single academic institution between 2006 and 2017.ResultsFifteen patients were identified. Eight had obstruction at the trachea and seven at the larynx. In the laryngeal obstructions, three expired shortly after birth, and one survived after spontaneous fistulization and subsequent EXIT to tracheostomy. The remaining three underwent in-utero treatment with laser laryngotomy. One had preterm premature rupture of membranes (PPROM), delivered 3 days post-operatively, and died. Two underwent EXIT to tracheostomy with one surviving to discharge and is currently 2 years old.ConclusionOur study demonstrates the outcomes of a large series of patients diagnosed with CHAOS. While mortality remains high, options for fetal intervention are being explored to allow alterations in the prenatal natural history and improve postnatal outcomes.Type of StudyRetrospective Treatment Study.Level of EvidenceLevel IV.     

Pharmacosimulation of delays and interruptions during administration of tirofiban: a systematic comparison between EU and US dosage regimens

Journal of Thrombosis and Thrombolysis - Tirofiban is a glycoproteine (GP) IIb/IIIa receptor antagonist, which inhibits platelet-platelet aggregation and is a potential adjunctive antithrombotic...     

Stability of buffered lidocaine and epinephrine used for local anesthesia

Buffered lidocaine has been recently recommended for local anesthesia, as there is less pain on injection of the buffered solution. Reduced pain on injection of lidocaine and epinephrine buffered to a neutral pH was confirmed in 20 subjects (P less than .01). Concentrations of buffered lidocaine and epinephrine were performed in order to evaluate their stability. Buffered lidocaine dropped to 66.1% of initial concentrations after 4 weeks when stored at 25 degrees C. Buffered epinephrine fell to 1.34% of its initial concentration under similar conditions. Buffered lidocaine and epinephrine maintained 94.54% and 82.04%, respectively, of their initial concentrations after 4 weeks when refrigerated at 0-4 degrees C. Both lidocaine and epinephrine maintained greater than 90% concentration 2 weeks after buffering when stored at 0-4 degrees C. This permits batch buffering of lidocaine with epinephrine and storage for periods up to 2 weeks when properly refrigerated.     

Frequency response of multi-phase segmented k-space phase-contrast

A theoretical analysis of the temporal frequency response of multi-phase segmented k-space phase-contrast was developed. This includes the effects of both segment duration and the number of cardiac phases that are reconstructed. An increase in the number of views per segment and the corresponding increase in segment duration results in an increased smoothing or low-pass filtering of the time-resolved flow waveform. Reconstruction of all intermediate cardiac phases makes the Nyquist sampling frequency independent of the number of views per segment. This analysis was verified experimentally using a multi-phase phase-contrast segmented k-space MR pulse sequence. This sequence reconstructs all intermediate cardiac phases and uses fractional segments at the end of the cardiac cycle if an entire segment does not fit. The use of fractional segments increases the portion of the cardiac cycle over which data are acquired.     

Effects of through-plane myocardial motion on phase-difference and complex-difference measurements of absolute coronary artery flow

We have previously reported on a complex-difference (CD) flow measurement technique that produces more accurate results than the phase-difference (PD) flow measurement technique due to the greater immunity of the former method to partial volume effects. We report here on some of the ways in which through-plane myocardial motion affects the accuracy of absolute coronary artery flow measurements obtained using the PD and CD techniques. We also discuss motion correction schemes that can be applied to the PD and CD processing methods to improve their accuracy. Computer simulations have been performed to assess the magnitude of the errors associated with these flow measurement techniques when they are applied to small vessels that are attached to a moving background. Laminar and plug flow, with and without complete background suppression, have been considered. Experiments with a moving vessel phantom have been conducted to test the performance of the PD and CD flow measurement techniques in circumstances similar to those simulated. The simulations and the experiments showed that, after corrections for throughplane motion are made, the CD method generally yields more accurate flow results than the PD method. As shown by the simulations, however, both methods yield compromised results due to subtle saturation effects that occur when the direction of myocardial motion is opposite the direction of blood flow. Unvalidated PD and CD measurements of coronary artery flow waveforms in human volunteers are presented to illustrate the magnitude of the proposed throughplane motion effects in vivo.     

A complex-difference phase-contrast technique for measurement of volume flow rates

Magnetic resonance (MR) phase-difference methods work well for measuring volumetric flow rates when the vessel diameter is large compared with the in-plane voxel dimensions. For small vessels (eg, coronary arteries), partial-volume effects introduce substantial errors in the measured volume flow rate. To correctly measure flow rates through a voxel, both the fraction of the voxel containing moving spins and the phase shift imparted to those spins must be known. The authors propose a flow measurement method that combines information obtained with both the complex-difference and phase-difference processing techniques and thereby provides the fractional volume occupied by the moving spins and the phase of those spins. The complex-difference flow map method proposed results in improved accuracy of MR phase-contrast flow measurements in the presence of partial-volume effects.     

Mechanical factors in the etiology of premature rupture of the membranes.

The physiologic cascade that results in PROM is cyclic and probably can be entered at many points--through the production of collagenases, peroxidases, phospholipases, or prostaglandins. It can be initiated or exacerbated by bacteria. In addition, PROM is the result of direct bacterial insults or host-mediated autodestruction in response to bacterial presence or challenge. It may be affected by physical properties and stresses that are mechanical. This review of the mechanical factors that support normal chorioamnion membranes may provide an understanding of where the support can be eroded, thus leading to PROM. With this basic overview of the pathophysiology contributing to PROM, the clinician can justify clinical decisions better, depending on the patient's presentation and gestational age. The judicious use of various tocolytic agents, antimicrobial agents, and/or corticosteroids singly or in combination is predicated on the effect each of these iatrogenically administered agents will have on the mother and fetus. As more investigations are done, we will gain greater insight into the mechanical factors involved in causing PROM.     

Severe preeclampsia and delivery outcomes: is immediate cesarean delivery beneficial?

OBJECTIVE: This study was designed to determine whether immediate cesarean delivery for patients with severe preeclampsia confers any benefit to the mother or neonate. STUDY DESIGN: This retrospective chart review included all deliveries complicated by severe preeclampsia between July 1, 1999, and June 30, 2000. Cesarean deliveries performed for malpresentation, previous classic incision, multiple gestation, placenta previa, and herpetic outbreak were not included. Demographic variables, maternal outcomes, and neonatal outcomes were collected. RESULTS: Of 114 patients, 93 had an option regarding route of delivery. Thirty-four had an immediate cesarean section and 59 had induction of labor. Thirty-seven of 59 were delivered vaginally and 22 of 59 underwent cesarean delivery. Pulmonary complications in the mother and neonate were more common in cesarean delivery (P <.05). No morbidity was decreased by cesarean delivery. Bishop score and gestational age did not affect the labor induction success rate. CONCLUSION: Immediate cesarean delivery confers no benefit to patients with severe preeclampsia.