Stability of a trapped atom clock on a chip

We present a compact atomic clock interrogating ultracold 87Rb magnetically trapped on an atom chip. Very long coherence times sustained by spin self-rephasing allow us to interrogate the atomic transition with 85% contrast at 5 s Ramsey time. The clock exhibits a fractional frequency stability of $5.8\times 10^{-13}$ at 1 s and is likely to integrate into the $1\times10^{-15}$ range in less than a day. A detailed analysis of 7 noise sources explains the measured frequency stability. Fluctuations in the atom temperature (0.4 nK shot-to-shot) and in the offset magnetic field ($5\times10^{-6}$ relative fluctuations shot-to-shot) are the main noise sources together with the local oscillator, which is degraded by the 30% duty cycle. The analysis suggests technical improvements to be implemented in a future second generation set-up. The results demonstrate the remarkable degree of technical control that can be reached in an atom chip experiment.Comment: 12 pages, 11 figure

Neurodevelopmental outcome at 5 years of age after general anaesthesia or awake-regional anaesthesia in infancy (GAS)trial

Background: In laboratory animals, exposure to most general anaesthetics leads to neurotoxicity manifested by neuronal cell death and abnormal behaviour and cognition. Some large human cohort studies have shown an association between general anaesthesia at a young age and subsequent neurodevelopmental deficits, but these studies are prone to bias. Others have found no evidence for an association. We aimed to establish whether general anaesthesia in early infancy affects neurodevelopmental outcomes. Methods: In this international, assessor-masked, equivalence, randomised, controlled trial conducted at 28 hospitals in Australia, Italy, the USA, the UK, Canada, the Netherlands, and New Zealand, we recruited infants of less than 60 weeks' postmenstrual age who were born at more than 26 weeks

Phase IV, Open-Label, Safety Study Evaluating the Use of Dexmedetomidine in Pediatric Patients Undergoing Procedure-Type Sedation

Dexmedetomidine (Precedex™) may be used as an alternative sedative in children, maintaining spontaneous breathing, and avoiding tracheal intubation in a non-intubated moderate or deep sedation (NI-MDS) approach. This open-label, single-arm, multicenter study evaluated the safety of dexmedetomidine in a pediatric population receiving NI-MDS in an operating room or a procedure room, with an intensivist or anesthesiologist in attendance, for elective diagnostic or therapeutic procedures expected to take at least 30 min. The primary endpoint was incidence of treatment-emergent adverse events (TEAEs). Patients received one of two doses dependent on age: patients aged ≥28 weeks' gestational age to <1 month postnatal received dose level 1 (0.1 μg/kg load; 0.05–0.2 μg/kg/h infusion); those aged 1 month to <17 years received dose level 2 (1 μg/kg load; 0.2–2.0 μg/kg/h infusion). Sedation efficacy was assessed and defined as adequate sedation for at least 80% of the time and successful completion of the procedure without the need for rescue medication. In all, 91 patients were enrolled (dose level 1, n = 1; dose level 2, n = 90); of these, 90 received treatment and 82 completed the study. Eight patients in dose level 2 discontinued treatment for the following reasons: early completion of diagnostic or therapeutic procedure (n = 3); change in medical condition (need for intubation) requiring deeper level of sedation (n = 2); adverse event (AE; hives and emesis), lack of efficacy, and physician decision (patient not sedated enough to complete procedure; n = 1 each). Sixty-seven patients experienced 147 TEAEs. The two most commonly reported AEs were respiratory depression (bradypnea; reported per protocol-defined criteria, based on absolute respiratory rate values for age or relative decrease of 30% from baseline) and hypotension. Four patients received glycopyrrolate for bradycardia and seven patients received intravenous fluids for hypotension. SpO2 dropped by 10% in two patients, but resolved without need for manual ventilation. All other reported AEs were consistent with the known safety profile of dexmedetomidine. Two of the 78 patients in the efficacy-evaluable population met all sedation efficacy criteria. Dexmedetomidine was well-tolerated in pediatric patients undergoing procedure-type sedation

The Effect of Tonsillectomy and Adenoidectomy on Upper Airway Obstruction Patterns in Children with Obstructive Sleep Apnea

Introduction Alterations in upper airway flow dynamics and sites of airway obstruction immediately after tonsillectomy and adenoidectomy (TA) have not been assessed. Identification of the changes in airway obstruction patterns after TA potentially improves the surgical management of children with obstructive sleep apnea (OSA). Objective To evaluate the effect of TA on upper airway obstruction patterns detected with drug-induced sleep endoscopy (DISE). Methods The medical records of patients who underwent pre-TA DISE during the induction of anesthesia and post-TA DISE at the end of TA were reviewed. Data pertaining to polysomnography and DISE findings were analyzed. Results Twenty-seven patients (15 male and 12 females aged between 2 and 18 years old) were identified. All patients had obstruction at multiple sites of the upper airway. Prior to TA, airway obstruction was at the level of the velum in 27 patients, of the oropharynx/lateral walls in 27, of the tongue in 7, and of the epiglottis in 4. After TA, airway obstruction was at the level of the velum in 24 patients, of the oropharynx/lateral walls in 16, of the tongue in 6, and of the epiglottis in 4. The degree of obstruction at the levels of the velum and oropharynx/lateral walls after TA was significantly decreased. Conclusions Drug-induced sleep endoscopy performed prior to TA revealed that most of the sites of airway obstruction persisted after TA in OSA children with multiple sites of airway obstruction. Further studies in larger group of children with OSA are needed to establish the value of DISE findings in predicting residual OSA after TA, surgical planning, determining the need for post TA sleep study, and counseling caregivers

Identification of the Epidural Space Using Pressure Measurement With the Compuflo Injection Pump – A Pilot Study

While epidural anesthesia (EA) is frequently used, success rate varies and complications associated with incorrect needle placement can occur. Different methods of objective identification of the epidural space (ES) have been suggested, without receiving widespread popularity. This prospective pilot study evaluated continuous pressure measurement during low speed injection with a computerized injection pump to objectively identify the ES. While EA was performed using a conventional loss of resistance technique in 20 consecutive patients, the injection pump technology was used to obtain pressure readings from the supraspinous ligament, the ligamentum flavum, and the ES. In the next 20 patients, the epidural space was solely identified with the computerized injection pump. Pressure reading obtained during the first part of the study revealed significant differences between the ES vs. the supraspinous ligament, and the ES vs. the ligamentum flavum (8 mm Hg, 95% confidence interval [CI] 6-11 vs 79 mm Hg, 95% CI 74-83 and 92 mm Hg, 95% CI 83-102, respectively) ( P < .001). In the second part of the study, the injection pump allowed for successful identification of the ES and performance of EA in all 20 patients. This investigation demonstrates that a computerized injection pump can be used to identify the epidural space and can serve as a base for further comparative research to determine whether this technology can increase the success rate of EA or lower the incidence of side effects