Remifentanil alters sensory neuromodulation of swallowing in healthy volunteers: quantification by a novel pressure-impedance analysis

Exposure to remifentanil contributes to an increased risk of pulmonary aspiration, likely through reduced pharyngeal contractile vigor and diminished bolus propulsion during swallowing. We employed a novel high-resolution pressure-flow analysis to quantify the biomechanical changes across the upper esophageal sphincter (UES). Eleven healthy young (23.3 ± 3.1 yr old) participants (7 men and 4 women) received remifentanil via intravenous target-controlled infusion with an effect-site concentration of 3 ng/ml. Before and 30 min following commencement of remifentanil administration, participants performed ten 10-ml saline swallows while pharyngoesophageal manometry and electrical impedance data were recorded using a 4.2-mm-diameter catheter housing 36 circumferential pressure sensors. Remifentanil significantly shortened the duration of UES opening ( P < 0.001) and increased residual UES pressure ( P = 0.003). At the level of the hypopharynx, remifentanil significantly shortened the latency from maximum bolus distension to peak contraction ( P = 0.004) and significantly increased intrabolus distension pressure ( P = 0.024). Novel mechanical states analysis revealed that the latencies between the different phases of the stereotypical UES relaxation sequence were shortened by remifentanil. Reduced duration of bolus flow during shortened UES opening, in concert with increased hypopharyngeal distension pressures, is mechanically consistent with increased flow resistance due to a more rapid bolus flow rate. These biomechanical changes are congruent with modification of the physiological neuroregulatory mechanism governing accommodation to bolus volume.

Effect of nasal noninvasive respiratory support methods on pharyngeal provocation-induced aerodigestive reflexes in infants

The pharynx is a locus of provocation among infants with aerodigestive morbidities manifesting as dysphagia, life-threatening events, aspiration-pneumonia, atelectasis, and reflux, and such infants often receive nasal respiratory support. We determined the impact of different oxygen delivery methods on pharyngeal stimulation-induced aerodigestive reflexes [room air (RA), nasal cannula (NC), and nasal continuous positive airway pressure (nCPAP)] while hypothesizing that the sensory motor characteristics of putative reflexes are distinct. Thirty eight infants (28.0 ± 0.7 wk gestation) underwent pharyngoesophageal manometry and respiratory inductance plethysmography to determine the effects of graded pharyngeal stimuli ( n = 271) on upper and lower esophageal sphincters (UES, LES), swallowing, and deglutition-apnea. Comparisons were made between NC ( n = 19), nCPAP ( n = 9), and RA ( n = 10) groups. Importantly, NC or nCPAP (vs. RA) had: 1) delayed feeding milestones ( P < 0.05), 2) increased pharyngeal waveform recruitment and duration, greater UES nadir pressure, decreased esophageal contraction duration, decreased distal esophageal contraction amplitude, and decreased completely propagated esophageal peristalsis (all P < 0.05), and 3) similarly developed UES contractile and LES relaxation reflexes ( P > 0.05). We conclude that aerodigestive reflexes were similarly developed in infants using noninvasive respiratory support with adequate upper and lower aerodigestive protection. Increased concern for GERD is unfounded in this population. These infants may benefit from targeted oromotor feeding therapies and safe pharyngeal bolus transit to accelerate feeding milestones.

Esophageal reflexes modulate frontoparietal response in neonates: Novel application of concurrent NIRS and provocative esophageal manometry

Central and peripheral neural regulation of swallowing and aerodigestive reflexes is unclear in human neonates. Functional near infrared spectroscopy (NIRS) is a noninvasive method to measure changes in oxyhemoglobin (HbO) and deoxyhemoglobin (HbD). Pharyngoesophageal manometry permits evaluation of aerodigestive reflexes. Modalities were combined to investigate feasibility and to test neonatal frontoparietal cortical changes during pharyngoesophageal (visceral) stimulation and/or swallowing. Ten neonates (45.6 ± 3.0 wk postmenstrual age, 4.1 ± 0.5 kg) underwent novel pharyngoesophageal manometry concurrent with NIRS. To examine esophagus-brain interactions, we analyzed cortical hemodynamic response (HDR) latency and durations during aerodigestive provocation and esophageal reflexes. Data are presented as means ± SE or percent. HDR rates were 8.84 times more likely with basal spontaneous deglutition compared with sham stimuli ( P = 0.004). Of 182 visceral stimuli, 95% were analyzable for esophageal responses, 38% for HDR, and 36% for both. Of analyzable HDR ( n = 70): 1) HbO concentration (μmol/l) baseline 1.5 ± 0.7 vs. 3.7 ± 0.7 poststimulus was significant ( P = 0.02), 2) HbD concentration (μmol/l) between baseline 0.1 ± 0.4 vs. poststimulus −0.5 ± 0.4 was not significant ( P = 0.73), and 3) hemispheric lateralization was 21% left only, 29% right only, and 50% bilateral. During concurrent esophageal and NIRS responses ( n = 66): 1) peristaltic reflexes were present in 74% and HDR in 61% and 2) HDR was 4.75 times more likely with deglutition reflex vs. secondary peristaltic reflex ( P = 0.016). Concurrent NIRS with visceral stimulation is feasible in neonates, and frontoparietal cortical activation is recognized. Deglutition contrasting with secondary peristalsis is related to cortical activation, thus implicating higher hierarchical aerodigestive protective functional neural networks.

Balloon Dilation in Sporadic Inclusion Body Myositis Patients with Dysphagia

Here, we describe balloon catheter dilation at the upper esophageal sphincter (UES) in three sporadic inclusion body myositis (s-IBM) patients with dysphagia. Initially, we performed IVIg therapy, and, three months later, switched to balloon dilation therapy. A 12-Fr balloon catheter was inserted from the mouth under fluoroscopy and the balloon inflated at the UES. The catheter was pulled back and re-inserted several times. We examined videofluoroscopy (VF) and pressure at the oropharynx, hypopharynx and UES using computed pharyngoesophageal manometry (CPM). Before both therapies, the VF study revealed a very small amount of barium paste passing through the UES. After balloon dilation therapy, as well as IVIg, subjective complaints of dysphagia disappeared and the VF study revealed an increased amount of barium paste passing through the UES. We conclude that balloon dilation therapy is a complementary method for conventional dysphagia therapies in s-IBM patients with dysphagia.

Cricopharyngeal Myotomy: Management of Cervical Dysphagia

Cricopharyngeal myotomy has gained widespread acceptance as surgical treatment for various forms of cervical dysphagia. The case records of 33 patients who underwent cricopharyngeal myotomy for dysphagia originating from varying underlying diseases are reviewed. The majority of these patients were able to resume oral feeding following myotomy. Analysis of preoperative pharyngoesophageal manometry and contrast radiography identified diagnostic criteria for appropriate case selection.