Resuscitation and auto resuscitation by airway reflexes in animals

Abstract

Various diseases often result in decompensation requiring resuscitation. In infants moderate hypoxia evokes a compensatory augmented breath – sigh and more severe hypoxia results in a solitary gasp. Progressive asphyxia provokes gasping respiration saving the healthy infant – autoresuscitation by gasping. A neonate with sudden infant death syndrome, however, usually will not survive. Our systematic research in animals indicated that airway reflexes have similar resuscitation potential as gasping respiration. Nasopharyngeal stimulation in cats and most mammals evokes the aspiration reflex, characterized by spasmodic inspiration followed by passive expiration. On the contrary, expiration reflex from the larynx, or cough reflex from the pharynx and lower airways manifest by a forced expiration, which in cough is preceded by deep inspiration. These reflexes of distinct character activate the brainstem rhythm generators for inspiration and expiration strongly, but differently. They secondarily modulate the control mechanisms of various vital functions of the organism. During severe asphyxia the progressive respiratory insufficiency may induce a life-threatening cardio-respiratory failure. The sniff- and gasp-like aspiration reflex and similar spasmodic inspirations, accompanied by strong sympatho-adrenergic activation, can interrupt a severe asphyxia and reverse the developing dangerous cardiovascular and vasomotor dysfunctions, threatening with imminent loss of consciousness and death. During progressive asphyxia the reversal of gradually developing bradycardia and excessive hypotension by airway reflexes starts with reflex tachycardia and vasoconstriction, resulting in prompt hypertensive reaction, followed by renewal of cortical activity and gradual normalization of breathing. A combination of the aspiration reflex supporting venous return and the expiration or cough reflex increasing the cerebral perfusion by strong expirations, provides a powerful resuscitation and autoresuscitation potential, proved in animal experiments. They represent a simple but unique model tested in animal experiments.

Delivery room deaths of extremely preterm babies: an observational study

“…Its use to stop gasping by dying neonates is not evidence-based and is hard to justify, as gasping respiration is known to be a brainstem autoresuscitation reflex secondary to asphyxia; it is characterised by markedly depressed brain function with a flat EEG30 31 and is not associated with the transmission of a painful stimulus. Neither opioids nor sedatives have been shown to reduce this sign 32 33.…”

Autoresuscitation and pheochromocytoma multisystem crisis in a dog

“…The ability of agonal breathing (gasping) to maintain some blood flow by producing some cardiac output and cerebral blood flow has been demonstrated in experimental swine studies, a response that should increase the likelihood of resuscitation 8–10 . Indeed, the aspiration reflexes and expiratory reflexes have been described in other experimental animals and infants, and appear to promote autoresuscitation by increasing venous return and cerebral perfusion 11 . Autoresuscitation has been described in people after cardiac arrest from positive end‐expiratory pressure/dynamic pulmonary hyperinflation, myocardial reperfusion, myocardial stunning, alkalosis, hypothermia, hyperkalemia, Q‐T syndrome, transient asystole, unobserved minimal vital signs, and delayed action of drugs.…”

“…[8][9][10] Indeed, the aspiration reflexes and expiratory reflexes have been described in other experimental animals and infants, and appear to promote autoresuscitation by increasing venous return and cerebral perfusion. 11 Autoresuscitation has been described in people after cardiac arrest from positive end-expiratory pressure/dynamic pulmonary hyperinflation, myocardial reperfusion, myocardial stunning, alkalosis, hypothermia, hyperkalemia, Q-T syndrome, transient asystole, unobserved minimal vital signs, and delayed action of drugs. However, associations were extrapolated from case reports, and few data exist on true etiologies of autoresuscitation.…”

Late, Transient Return of Pulsatility: Should We Change Donation after Circulatory Death Protocols?

“…Lumsden noted in 1923, in a systematic study using cat brains, that gasping was the last respiratory reflex to remain active before brainstem death, and reflex gasping has indeed been commonly documented minutes after circulatory arrest 13 . It is conceivable that postcirculatory arrest gasping, especially against an obstructed airway, may increase venous return to the heart and even provide forward arterial flow allowing temporary return of myocardial contractility and ROSC 14 .…”