Esophago-glottal closure reflex in human infants: a novel reflex elicited with concurrent manometry and ultrasonography

Abstract

Background and aims: Our aims were to identify and characterize the glottal response to esophageal mechanostimulation in human infants. We tested the hypotheses that glottal response is related to the type of esophageal peristaltic response, stimulus volume, and respiratory phase.

Methods: Ten infants (2.8 kg, SD 0.5) were studied at 39.2 wk (SD 2.4). Esophageal manometry concurrent with ultrasonography of the glottis (USG) was performed. The sensory-motor characteristics of mechanostimulation-induced esophago-glottal closure reflex (EGCR, adduction of glottal folds upon esophageal provocation) were identified. Mid-esophageal infusions of air (N = 41) were given and the temporal relationships of glottal response with deglutition, secondary peristalsis (SP), and the respiratory phase were analyzed using multinomial logistic regression models.

Results: The frequency occurrence of EGCR (83%) was compared (P < 0.001) with deglutition (44%), SP (34%), and no esophageal responses (22%). The odds ratios (OR, 95% CI) for the coexistence of EGCR with SP (0.4, 0.06-2.2), deglutition (1.9, 0.1-26), and no response (1.9, 0.4-9.0) were similar. The response time for esophageal reflexes was 3.8 (SD 1.8) s, and for EGCR was 0.4 (SD 0.3) s (P < 0.001). Volume-response relationship was noted (1 mL vs 2 mL, P < 0.05). EGCR was noted in both respiratory phases; however, EGCR response time was faster during expiration (P < 0.05).

Conclusion: The occurrence of EGCR is independent of the peristaltic reflexes or the respiratory phase of infusion. The independent existence of EGCR suggests a hypervigilant state of the glottis to prevent retrograde aspiration during GER events.

Figure 1

Methods to elicit esophago-glottal interactions. A manometry catheter with ports in the pharynx, proximal esophagus, middle esophagus, and distal esophagus is shown. An ultrasound (USG) transducer was placed on the anterior aspect of the neck such that the vocal folds were visualized in real time. The stimulus was infused via the mid-esophageal infusion port, and the esophageal-glottal interactions were characterized.

Figure 2

Esophago-glottal closure reflex. Effects of esophageal stimulus (1 mL air) on glottal motion are shown. Inset represents the infusion signal given via the mid-esophageal manometry port, respiration recorded with respiratory inductance plethysmography, and ultrasound images of the glottis. Magnified images of infusion signal (arrow) concurrent with ultrasound (USG) image frames are shown. The duration of infusion with a time line is shown in milliseconds. The sequence of USG images of the glottis from abduction to complete adduction and back to abduction is shown. Note the occurrence of complete glottal adduction in USG frames IV and V upon esophageal stimulation. The measurement of the sequential time interval during EGCR for the onset of complete glottal adduction (response time, hashed cone) and the duration of complete adduction (total glottal closure) are also shown.

Figure 3

Effect of graded esophageal air stimuli on response latency and magnitude of glottal adduction. EGCR response time (gray cones) and glottal closure duration (black bars) at 1 mL and 2 mL volumes are shown. At the higher volume, the glottis takes a longer period to adduct, and remains fully adducted for a significantly longer period (P < 0.03).

Figure 4

Schematic representation of 4 possible scenarios (B, C, D, and E) for the occurrence of EGCR (horizontal bars) in relationship to the respiratory phase of the given infusion (arrows) is shown. All stimuli were given randomly with respect to the respiratory phase. Scenario (A) represents basal respiration seen during esophageal quiescence. In (B), infusion was given during inspiration and glottal adduction occurred in inspiration. In (C), infusion was given in inspiration and glottal adduction occurred in expiration. In (D), infusion was given in expiration and glottal adduction occurred in expiration. In (E), infusion was given in expiration and glottal adduction occurred in inspiration.