Swallow Function and Post-Swallow Residue in Dysphagic Patients With and Without a History of Pneumonia

BACKGROUND: Automated Impedance Manometry (AIM) analysis defines swallow metrics indicative of bolus timing and presence, contractile vigour and luminal diameter.The Swallow Risk Index (SRI) and integrated nadir impedance to impedance ratio (iZn/Z) are global indices correlating with aspiration risk and post-swallow residue respectively (Omari et al., Gastroenterology 2011; Omari et al., Neurogastro.Mot.2012).This study compared the SRI and iZn/Z ratio for controls and dysphagic patients with and without a history of pneumonia.METHODS: 87 asymptomatic controls 20-91y (39M, mean 59y) and 201 dysphagic patients 17-91y (117 male, mean 67y) were investigated.33 patients had history of pneumonia.Swallowing of 5-10ml liquid boluses was recorded by solid state manometryimpedance catheter (OD 3.2mm, 36 pressure at 1cm, 12 impedance at 2cm).AIMplot software was used to derive SRI and iZn/Z indices.RESULTS: 140 patients had abnormal swallow function (SRI>15).123 patients had significant post-swallow residue (iZn/Z .500).The SRI and iZn/Z ratio were higher in relation to dysphagia.Furthermore, the iZn/Z ratio was higher in dysphagic patients with a history of pneumonia compared to those with no history (See Figure ).The latency from bolus flow to pharyngeal contraction was shorter and pharyngeal bolus dwell time was longer in relation to pneumonia (ANOVA p ,0.001, p,0.05 for all pairwise comparisons).Pharyngeal pressures and UES relaxation pressures were not significantly different in relation to pneumonia.CONCLUSIONS: Pharyngeal HRIM with AIM analysis can detect increased swallow dysfunction and post-swallow residue in dysphagic patients.Patients with a history of pneumonia have higher post swallow residues.