The effects of change in pharyngeal airway pressure on electromyographic (EMG) activity a dilating muscle (genioglossus) were investigated 20 anesthetized rabbits. In vagotomized animals, upper loading maneuvers (nasal occlusion) increased the peak inspiratory genioglossus (GG) first occluded breath. contrast, “unloading” (switching from nose to tracheostomy breathing) decreased GG activity. To further characterize response, sustained changes produced within isolated airway. Negative...

The afferent pathway of an upper airway reflex in which genioglossus muscle electromyographic (GG EMG) activity is influenced by pharyngeal pressure changes was investigated 20 anesthetized rabbits. We took advantage the fact that separated into two compartments closure occurring when animals breathe through a tracheostomy. This allowed to be delivered selectively either nose and nasopharynx or larynx hypopharynx. Midcervical vagotomy did not eliminate GG EMG response stimuli. On other hand...

Influence of upper airway negative-pressure change on the respiratory activity various muscles was investigated in 13 anesthetized rabbits. Phasic inspiratory increased or appeared during virtually all trials nasolabial, cricothyroid, and posterior cricoarytenoid muscles. No phasic seen sternothyroid (ST) sternohyoid (SH) before applications but 80% ST 62% SH. During maintained negative pressure, a gradual decline often observed nasolabial laryngeal muscles, whereas rapid cervical strap...

• We attempted to determine whether differences in milk composition or flow rate are the primary determinants altering breathing pattern during nipple-feeding. In first phase of study, 15 neonates were studied breast-feeding and bottle-feeding; second phase, evaluated bottle-feeding expressed human formula. A reduction inspiratory duration was observed with all feeding regimens. Moreover, significant prolongation expiratory frequency formula (compared control); these effects greater feeding....

Receptors responding to transmural pressure, airflow, and contraction of laryngeal muscles have been previously identified in the larynx. To assess relative contribution these three types receptors reflex changes breathing pattern upper airway patency, we studied diaphragmatic (DIA) posterior cricoarytenoid muscle (PCA) activity anesthetized dogs during spontaneous occluded efforts with without bypassing Inspiratory duration (TI) was longer, mean inspiratory slope (peak DIA/TI) lower, PCA...

Forty-two oliguric neonates were prospectively studied to evaluate the usefulness and reliability of various diagnostic indices in differentiating renal failure from functional (prerenal) oliguria. Twenty-two infants had oliguria, 16 failure, four probable early failure. Statistically significant differences between oliguria found with regard urine sodium, serum ratios urea, creatinine, index, fractional excretion sodium. However, sharp demarcation two groups was possible only when index or...

Abstract The present study was designed to investigate the development of respiratory control during feeding in premature infants. Cardiorespiratory disturbances were evaluated with polygraphic monitoring 24 infants within 1 week beginning nipple feeds. During initial study, 15 exhibited one or more episodes short apnea (≥ 10 sec) and three prolonged (≥20 sec). Bradycardia developed seven infants; decreases oxygen saturation invariably preceded bradycardia. In contrast, occurred sleep five...

A current hypothesis for obstructive sleep apnea states that 1) negative airway pressure during inspiration can collapse the pharyngeal airway, and 2) neural control of airway-dilating muscles is important in preventing this collapse. To test we performed nasal mask occlusions to increase pressures eight normal five micrognathic infants. Both groups developed midinspiratory obstruction, but obstruction was more frequent infants varied some with state. The usually reopened subsequent...

A series of experiments was performed in rabbits to investigate the effects airway sensory stimuli on upper patency. Pharyngeal closure observed breathing through a tracheostomy tube; pharyngeal patency rapidly restored either by closing tube, which forced animals resume nasal breathing, or creating cyclical pressure changes nose and pharynx stimulate respiratory tidal airflow. This opening effect fluctuations eliminated topical anesthesia mucosa, an observation suggesting that stimulation...