Doppler echocardiograms of the tricuspid and mitral valves were recorded along with the electrocardiogram and respiration in 22 normal full-term neonates. A computer-interfaced digitizer pad was utilized to measure the following: peak E and A velocities (cm/s); E and A areas (the components of the total velocity-time integral in the early passive period of ventricular filling [E] and the late active period of atrial emptying [A], respectively) and the 1/3 area fraction (or the proportion of filling in the first 1/3 of diastole). All of the variables of right (tricuspid) versus left (mitral) ventricular filling were significantly different on the 1st day of life. Respective values were peak E velocity (cm/s) 44.6 +/- 10.0 (tricuspid) versus 53.2 +/- 9.3 (mitral), p less than 0.01; peak E/A ratio 0.84 +/- 0.14 versus 1.15 +/- 0.17, p less than 0.0001; E/total area 0.58 +/- 0.07 versus 0.63 +/- 0.05, p less than 0.005; E/A area ratio 1.05 +/- 0.23 versus 1.63 +/- 0.40, p less than 0.0001; 1/3 area fraction 0.31 +/- 0.04 versus 0.41 +/- 0.04, p less than 0.0001; peak A velocity (cm/s) 53.0 +/- 8.4 versus 47.6 +/- 5.8, p less than 0.05 and A/total area 0.57 +/- 0.09 versus 0.41 +/- 0.09, p less than 0.001; the mean heart rate (beats/min) was not significantly different: 121 +/- 8 versus 120 +/- 7. Most of the variables remained significantly different on the 2nd day of life, but the level of significance was the same or less for all measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of electrical stimulation of the denervated posterior cricoarytenoid (PCA) muscle on its subsequent reinnervation was explored in the canine. Eight animals were implanted with a planar array of 36 electrodes for chronic stimulation and recording of spontaneous and evoked electromyographic (EMG) potentials across the entire fan-shaped surface of a muscle pair. Normative EMG data were recorded from each electrode site before unilateral nerve section, and from the innervated partner after nerve section. After randomizing the animals to experimental and control groups, the right recurrent laryngeal nerve innervating the PCA abductor muscle and its adductor antagonists was sectioned and reanastomosed. The PCA muscle in four experimental animals was continuously stimulated during the 11-mo experiment, using a 1-s, 30-pps, biphasic pulse train composed of 1-ms pulses 2-6 mA in amplitude and repeated every 10 s. The remaining four animals served as nonstimulated controls. Appropriate reinnervation by native inspiratory motoneurons was indexed behaviorally by the magnitude of vocal fold opening and electromyographically by the potential across all electrode sites. Inappropriate reinnervation by foreign adductor motoneurons was quantitated by recording EMG potentials evoked reflexly by stimulation of sensory afferents of the laryngeal mucosa. All four experimental animals showed a greater level of correct PCA muscle reinnervation (P < 0.0064) and a lesser level of incorrect reinnervation (P < 0.0084) than the controls. Direct muscle stimulation also appeared to enhance the overall magnitude of reinnervation, but the effect was not as strong (P < 0.113). These findings are consistent with a previous report and suggest that stimulation of a mammalian muscle may profoundly affect its receptivity to reinnervation by a particular motoneuron type.

Intramuscular injection of botulinum toxin A is used to treat focal dystonias. Because immunoresistance has been documented in some patients, other molecular forms of the toxin have been evaluated clinically. The present investigation compared the time course and extent of neuromuscular blockade and recovery of botulinum toxin types A and F using an electromyographic monitoring system implanted in the rat hindlimb. For a given dose, the degree and duration of blockade was more complete with type A toxin. Delayed onset of recovery in animals that received high doses of type A toxin allowed time for denervative changes to prevent a full return to baseline, as confirmed histologically. Conversely, animals receiving type F toxin fully recovered within 30 days at all dose levels. The rapid recovery with type F toxin suggested that neuromuscular transmission was restored via the original terminals rather than through functional collateral sprouting. The reversible nature of blockade with this molecular species puts in question its future clinical utility.

SUPPORT) demonstrated that static low oxygen saturation decreased retinopathy of prematurity (ROP) but increased mortality compared with static high oxygen saturation cohorts.OBJECTIVE To compare outcomes of a biphasic oxygen protocol with static targets recommended by SUPPORT. DESIGN, SETTING, AND PARTICIPANTSRetrospective cohort study comparing biphasic vs static standards 41 months prior to and 42 months after a change from biphasic to static SUPPORT standards at a level III neonatal intensive care unit (Fairview Hospital, Cleveland, Ohio). The study included infants born at a corrected gestational age (CGA) of 31 weeks or younger or birth weight 1500 g or less. Data were analyzed between August 2010 and July 2017. INTERVENTIONSThe pre-SUPPORT group underwent biphasic protocol target saturations of 85% to 92% at younger than 34 weeks' CGA and greater than 95% at 34 weeks' CGA or older. The post-SUPPORT group underwent a constant 91% to 95% target.MAIN OUTCOMES AND MEASURES Primary outcome was incidence of type 1 ROP. Secondary outcomes were incidence of any ROP, time to full vascularization, and mortality. RESULTSOf 596 eligible infants, 562 were included in ophthalmic analysis. Three hundred three patients were boys (54%); 399 were white (71%), 87 were black (15%), and 76 were of other or unknown race/ethnicity (14%). Mean (SD) CGA and birth weight were 29 (2) weeks and 1151 (346) g, respectively. Any ROP overall increased (53 [20%] pre-SUPPORT vs n = 86 [28%] post-SUPPORT; absolute difference, 8%; 95% CI, 1%-15%; odds ratio, 1.6; 95% CI, 1.05-2.3; P = .03). Type 1 ROP increased in the post-SUPPORT era (n = 6 [2%] pre-SUPPORT vs n = 18 [6%] post-SUPPORT; absolute difference, 4%; 95% CI, 0.4%-7%; odds ratio, 2.7; 95% CI, 1.05-6.9; P = .03). There was a delay in vascularization in the post-SUPPORT group (n = 6 [2%] pre-SUPPORT vs n = 18 [6%] post-SUPPORT; absolute difference, 4%; 95% CI, 0.4%-7%; P = .03). CONCLUSIONS AND RELEVANCECompared with static oxygen standards, biphasic oxygen targets are associated with decreased incidence and severity of ROP without increasing mortality.

The optimal stimulus paradigm identified in this study (1 msec pulses delivered at 30 to 40 Hz and 2 to 8.5 mA) has been applied to implanted BVFP patients and improved outcome. Information regarding optimal electrode orientation could also be important to future clinical trials.

Gabapentin was well tolerated and associated with decreases in pain scores. It's use resulted in decreased requirements for analgesic and sedative medications. Gabapentin therapy appears to be an effective option for neonates and infants with refractory pain and agitation.

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BACKGROUND Opioids and benzodiazepines have been the mainstay of neonatal analgesia and sedation. However, based on evidence in neonatal animals, these drugs may be deleterious for the developing brain. Dexmedetomidine (DEX), a central alpha-2 agonist, has sedative and analgesic effects and has been shown to be neuroprotective in animal models. Despite increasing use of DEX in newborns, there is a paucity of data regarding its safety and efficacy in this population. OBJECTIVES The impact of using DEX in postsurgical neonates, either alone or with opioid infusions, for sedation/analgesia was evaluated. The cumulative dose of opioids among patients who did or did not receive DEX was calculated to examine the hypothesis that the addition of DEX can reduce the patient exposure to opioids without significantly increasing side effects and providing adequate sedation and pain control. METHODOLOGY This was a retrospective cohort study in which patients were matched by postnatal age and surgical procedure into 2 groups. One group received DEX in the regimen for treatment of pain or sedation after a surgical procedure, and the other group received no DEX. Episodes of bradycardia, respiratory depression and hypotension, and the cumulative dose of opioids and number of supplemental doses administered in both groups were documented. RESULTS Although there was no difference in gestational age or weight at birth between the DEX and no-DEX groups, the DEX group's median postconceptional date was older at the time of surgery (39.6 vs 37.4 weeks; p = 0.003). Patients in the DEX group experienced more episodes of bradycardia (12.8% vs 5.1%; p = 0.01). There was no difference between groups in episodes of hypotension or respiratory depression. The cumulative dose of opioids was significantly lower in the DEX group compared with the no-DEX group (1155 mcg/kg vs 1841 mcg/kg; p = 0.01). There was no difference in the number of supplemental doses of opioids given between the groups. CONCLUSIONS The addition of DEX to opioid infusions resulted in a significant decrease in the cumulative dose of opioids but was associated with more episodes of bradycardia than opioids alone.