Respiratory physiology & neurobiology
-
Respir Physiol Neurobiol · Oct 2014
Spontaneous swallowing occurs during autoresuscitation in the in situ brainstem preparation of rat.
Previous studies report that upper airway reflexes are operational during autoresuscitation from respiratory arrest. We investigated swallowing/breathing interactions, measured by recording of vagal (VNA) and phrenic nerve activities (PNA), during autoresuscitation in the in situ perfused brainstem preparation of juvenile rats. During the initial surgery, respiratory arrest was induced by exsanguination and cooling. ⋯ Successful autoresuscitation was characterised by re-establishment of the 3 phase respiratory motor pattern and no spontaneous swallowing. Pharmacological inhibition (isoguvacine, 10 mM, 50-75 nl; n=10) of the Kölliker-Fuse nucleus (KF) mimicked stage 2 autoresuscitation. However, the frequency of spontaneous swallowing after KF inhibition did not correlate with subsequent recovery of the eupneic respiratory motor pattern.
-
Respir Physiol Neurobiol · Oct 2014
Rabbit model of chest wall rigidity induced by fentanyl and the effects of apomorphine.
A rabbit model for fentanyl-induced chest wall rigidity and the effect of apomorphine was evaluated. Eleven New Zealand adult rabbits were anesthetized and mechanically ventilated. An esophageal balloon catheter was used to estimate pleural pressure (P(pl)). ⋯ In 5 rabbits, C(cw) decreased significantly after fentanyl administration and apomorphine was able to restore C(cw) to baseline values. Rabbits can be used as a model for fentanyl-induced chest wall rigidity. Results from this study support central dopaminergic pathways as being at least partially responsible for the opioid-induced chest wall rigidity.
-
Respir Physiol Neurobiol · Oct 2014
Laryngeal narrowing during nasal ventilation does not originate from bronchopulmonary C-fibers.
We previously showed that nasal pressure support ventilation (nPSV) can lead to active inspiratory laryngeal narrowing, which originates from the stimulation of bronchopulmonary receptors. Among the three major types of bronchopulmonary receptors, which are variably stimulated by lung distension, C-fiber endings are remarkable, given that their stimulation can also trigger laryngeal closure. Taking advantage of our lamb model with blocked C-fibers, we aimed to assess whether bronchopulmonary C-fiber endings are involved in the active inspiratory laryngeal narrowing during nPSV. ⋯ Forty-eight hours later, two polysomnographic recordings were performed during nPSV 15/4 cmH2O, before and after C-fiber blockade. During nPSV, blockade of C-fibers did not prevent inspiratory EaTA (present for 74±41% of respiratory cycles vs. 64±35%, p=0.9). We conclude that active inspiratory laryngeal narrowing during nPSV does not originate from bronchopulmonary C-fiber endings.
-
Respir Physiol Neurobiol · Oct 2014
Randomized Controlled TrialFlow Controlled Expiration is perceived as less uncomfortable than positive end expiratory pressure.
Recently, we presented Flow Controlled Expiration (FLEX) as a new option for lung-protective ventilation. FLEX delays the expiratory volume decrease in the lungs without prolonging the duration of expiration. Most ventilated patients nowadays receive spontaneous breathing support. ⋯ Only in forced choice comparison a stronger FLEX condition was perceived as less comfortable (p<0.01) than a weaker one. We conclude that FLEX decreases the breathing comfort in healthy subjects to a lesser extent than PEEP. Therefore, FLEX might be used to support ventilation therapy in spontaneously breathing patients.