title: Correctly selecting a liquid-filled nasogastric infant feeding catheter to measure intraesophageal pressure.
abstract: Polyvinyl chloride (PVC) nasogastric feeding catheters are used clinically to measure intraesophageal pressure as an estimate of pleural pressure for calculating lung compliance in infants. The accuracy of pressure measurement of 4 French gauge (FG) catheter sizes and three brands of liquid-filled catheter manometer systems (CMS) was evaluated by determining their resonance-frequency amplitude and phase properties. All CMS were underdamped and resonated. No CMS exhibited a uniform mean frequency response above 11 Hz. The maximum respiratory rate (Frr) within which CMS could potentially measure dynamic intraesophageal pressure within a 5% error limit was determined (Frr): the highest mean Frr recorded reliably in large-diameter catheters was 82 breaths/min. Significant CMS differences in accuracy existed between catheter FG sizes and between catheters of similar diameters but differing brands. Correlation (r2) between catheter inner diameter and CMS Frr was 0.66 across brands. In conclusion, intraesophageal PVC liquid-filled feeding catheters are suitable for estimating pleural pressures in subjects mechanically ventilated without sharp inspiratory waveforms or high respiratory rates. Quantitative frequency response characterization of different nasogastric catheter brands and different diameters is mandatory prior to their utilization.
authors.affiliation: Department of Physiology, University of Witwatersrand, Johannesburg, South Africa.
authors.forename: C G
authors.initials: CG
authors.lastname: Hartford
authors.forename: G G
authors.initials: GG
authors.lastname: Rogers
authors.forename: M J
authors.initials: MJ
authors.lastname: Turner
mesh_terms: D000367:Age Factors; D015982:Bias; D002408:Catheters, Indwelling / Q000592:standards*; D004750:Enteral Nutrition / Q000295:instrumentation*; D004867:Equipment Design; D004947:Esophagus / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D007441:Intubation, Gastrointestinal / Q000295:instrumentation*; D008170:Lung Compliance; D008365:Manometry / Q000295:instrumentation*; D008422:Materials Testing; D010994:Pleura / Q000502:physiology*; D011143:Polyvinyl Chloride; D015203:Reproducibility of Results; D012119:Respiration
chemical_list: D011143:Polyvinyl Chloride