Return Of Respiration Research Articles

Comparison of the effects of remifentanil and dexmedetomidine on surgeon satisfaction with surgical field visualization and intraoperative bleeding during rhinoplasty

ObjectiveWe aimed to compare the effect of dexmedetomidine with remifentanil on hemodynamic stability, surgical field quality, and surgeon satisfaction during rhinoplasty.Methods and materialsIn this double-blind randomized controlled-trial, 60 participants scheduled for rhinoplasty at the Mother and Child Hospital, Shiraz, Iran, was randomely divided into the dexmedetomidine group (IV infusion of 1 μg/kg dexmedetomidine over 20 min before induction of anesthesia then 0.6 μg/kg/hr. dexmedetomidine from the time of induction until the end of the operation) or in the the remifentanil group (an infusion rate of 0.25 μg/kg/min from the time of anesthesia induction until the end of the operation). Bleeding volume, surgeon satisfaction, postoperative pain (visual analog scale (VAS)), Level of sedation (Richmond Agitation Sedation Scale (RASS)), Patient satisfaction, Vital signs & recovery, and the Aldrete Score (used to discharge the patients from recovery) were measured for all participants.ResultsThe patients in the dexmedetomidine group had less bleeding (p = 0.047) and shorter time to return of respiration, extubation, and the postoperative recovery time (p < 0.001). The surgeon satisfaction was higher in the dexmedetomidine group (p < 0.001). Patient satisfaction was significantly different between the two groups (p < 0.001). VAS scores, intaking paracetamol, and RASS score were significantly lower in the remifentanil group (p < 0.001). SBP, DBP, MAP, and heart rate were lower in dexmedetomidine group.ConclusionDexmedetomidine was associated with relatively stable hemodynamics, leading to decreased intraoperative bleeding, recovery time, and greater surgeon satisfaction and the level of consciousness in the recovery ward. However, painlessness and patient satisfaction were greater with the use of remifentanil.Trial registrationIRCT20141009019470N112.

Unassisted Return of Spontaneous Circulation Following Withdrawal of Life-Sustaining Therapy During Donation After Circulatory Determination of Death in a Child

To describe the unassisted return of spontaneous circulation following withdrawal of life-sustaining treatment in a child. Case report based on clinical observation and medical record review. Community Children's Hospital. Two-year old child. Following hypoxic-ischemic brain injury, the child was taken to the operating room for withdrawal of life-sustaining treatment during controlled donation after circulatory determination of death. In addition to direct observation by experienced pediatric critical care providers, the child was monitored with electrocardiography, pulse oximetry, and invasive blood pressure via femoral arterial catheter in addition to direct observation by experienced pediatric critical care providers. Unassisted return of spontaneous circulation occurred greater than 2 minutes following circulatory arrest and was accompanied by return of respiration. We provide the first report of unassisted return of spontaneous circulation following withdrawal of life-sustaining treatment in a child. In our case, return of spontaneous circulation occurred in the setting of controlled donation after circulatory determination of death and was accompanied by return of respiration. Return of spontaneous circulation greater than 2 minutes following circulatory arrest in our patient indicates that 2 minutes of observation is insufficient to ensure that cessation of circulation is permanent after withdrawal of life-sustaining treatment in a child.

Divergent synaptic influences affecting discharge pattering of genioglossus motor units

Discharge patterns of single motor units were recorded from 5 inframandibular muscles in acutely prepared adult rhesus monkeys and cats. The alterations in interspike interval patterns were studied in genioglossus motor units during respiration, swallowing, laryngeal, and precentral cortex stimulation in animals anesthetized with urethane. Genioglossus motor units were active in both inspiration and swallowing with 87% of the units demonstrating a significant difference in distributions of their first order interspike interval histograms in swallowing as compared to their respiratory pattern. Interaction between several swallows and the prolonged inhibition of respiration (1–7 sec) altered the discharge pattern of a genioglossus unit from its activity during normal respiration. This significant change in the distribution of the interspike intervals of the motor unit in both first order and autocorrelation histograms occurred during the marked increase in intensity and duration of the gross EMG of the genioglossus muscle during the return of respiration. Stimulation of the precentral cortex of the rhesus monkey indicated a third central synaptic influence on the genioglossus motoneurons with a given motor unit discharging in masticatory movements and swallowing. A first order latency histogram demonstrated a fourth synaptic influence with a correlation between the stimulus pulse to the superior laryngeal nerve innervating the laryngeal region and the latency to when a genioglossus motor unit discharged. The latency analysis suggested a vago-hypoglossal reflex from sensory input of the laryngeal region synaptically affecting genioglossus motoneurons by a polysynaptic pathway.

Effects of muscarine given into the brain of fowls.

1. The effects of muscarine, given intraventricularly, in adult conscious fowls (Gallus domesticus) or microinfused into various brain regions of conscious young chicks, were tested on behaviour, electrocortical activity and respiratory rate. Its effects given intraventricularly or intravenously to anaesthetized fowls were also examined.2. After intraventricular injection, muscarine elicited immediate behavioural and electrocortical arousal; body temperature was unaffected. After a delay of 30-40 min, tachypnoea developed together with postural changes which included partial abduction of the wings away from the trunk, the back and tail becoming horizontal. These effects were prevented by intravenous or intraperitoneal atropine or hyoscine, but not by pempidine or methylatropine, and were potentiated by physostigmine. Hyoscine given intraventricularly or intravenously did not affect electrocortical activity.3. Intraventricular muscarine given to anaesthetized adult fowls produced brief apnoea. On return of respiration, amplitude of respiratory excursion was diminished for about 5 min; tachypnoea did not develop. Blood pressure also rose briefly. With larger doses of intraventricular muscarine, large amplitude electromyographic potentials developed in the dorsal neck muscles followed later by side-to-side neck movements.4. Muscarine given intravenously to anaesthetized adult fowls, raised blood pressure and perfusion pressure in a perfused hind limb, an effect most likely due to secretion of adrenal medullary catecholamines; these pressor effects were prevented by pempidine and phenoxybenzamine. Given directly to the perfused hind limb, muscarine lowered perfusion pressure.5. In young chicks, muscarine microinfused into the diencephalon or myelencephalon elicited intense bilateral electrocortical alerting associated with periods of alternating violent motor activity and quiescence. Microinfusion of muscarine into the telencephalon induced ipsilateral electrocortical desynchronization without affecting behaviour. These effects of muscarine were prevented by intravenous, intraperitoneal or intracerebral hyoscine, but once its effects were established could be antagonized only with difficulty; pempidine did not prevent these effects. Microinfusions of muscarine into the brain did not affect posture, respiration or temperature.

Hypersomnia and Periodic Respiration–Presentation of Two Cases* and Comment on the Physio-Pathogenesis of the Pickwickian Syndrome

Summary Two patients with prominent hypersomnia during daytime and frequent, periodic apnea during sleep are reported. The 1st case was without obesity or hypercapnia during waking period. She had ankylosis of the jaw joints. The 2nd case was a typical of the Pickwickian syndrome with marked obesity and hypercapnia in the awake state. Both of the patients showed frequent, periodic apnea lasting 10–48 sec only during sleep. Duration of the apneic period was longest in the paradoxical phase of sleep with rapid eye movements. Return of respiration at the end of the apnea was always just preceded by arousal response in the EEG: K-complex with or without appearance of alpha rhythm. Thus, their nocturnal sleep was constantly fragmented due to the periodic apnea. Stable, deep sleep with high voltage slow waves was much reduced in the 1st case and it was completely absent in the 2nd case. The periodic apnea in the two patients was of obstructive type. Respiratory movement of the thorax accompanied by EMG activity in the inter-costal muscles persisted even during the apneic period. It was confirmed in the 1st case by radiological examination performed during sleep with the use of a television that the base of her tongue dropped down back into the hypopharynx obstructing this completely during apneic period. Tracheotomy and insertion of tracheal canule resulted disappearance of the periodic apnea during sleep and of hypersomnia during daytime. It is concluded from the above findings that hypersomnia in our patients is due to, and is compensating for the sleep disturbance in the night. Physio-pathogenesis of the Pickwickian syndrome are briefly discussed in the light of the present findings with reference to previous works.

Respiratory and cardiovascular changes during asphyxia and resuscitation of foetal and newborn rabbits.

A study has been made of the respiratory and circulatory responses to asphyxia and resuscitation of fœtal and newborn rabbits. Fœtuses were both delivered and maintained under isotonic saline, while newborn animals were asphyxiated in an atmosphere of N2 after light ether anæsthesia. Both groups were resuscitated by intermittent positive pressure ventilation with 02, begun after the last spontaneous gasp of asphyxia.The response to asphyxia was very similar in the two groups. There was a short initial period of (primary) apnœa, accompanied by a sudden fall in heart rate and blood pressure. This hypotension and bradycardia during the early part of asphyxia was reduced by vagotomy. Following primary apnœa, the animals gasped for some 15–20 min. and then again became apnœic (secondary apnœa). The heart rate and blood pressure fell further and, in the absence of external interference, the animals died. Resuscitation was successful, provided the blood pressure was above 5 mm. Hg at the start of I.P.P. ventilation. The heart rate and blood pressure invariably rose before the return of respiration in the successful cases. The Hering‐Breuer and paradoxical reflexes were fully active in the newborn rabbit, but were abolished by asphyxia due to a central nervous block. They did not return for several minutes after resuscitation.