Intraluminal esophageal manometry: an analysis of variables affecting recording fidelity of peristaltic pressures

Accurate recording of intraluminal esophageal pressure is important for satisfactorily examining esophageal motor function. This study evaluates the performance characteristics of 2 systems currently used for recording esophageal pressure: the infused catheter system, and an intraluminal transducer system. The investigation featured 3 general types of tests: bench studies, esophageal specimen studies, and manometric studies in man. For infusion manometry, the effects on recording fidelity of certain variables such as catheter diameter, catheter length, infusion rate (IR), pressure amplitude (Amp), and pressure complex duration (Dur) were determined. The major cause of recording error by infusion manometry was 'failure' of fluid delivery by the infusion pump during a pressure transient. During pressure transients, the pump syringe system delivered as little as 15% of its rated setting. Recording accuracy was inversely related to Amp and directly related to complex Dur and IR. For infusion manometry, pressure Amp was recorded accurately at an IR of 1.6 or 3.1 ml per min in the thoracic esophagus, whereas an IR of 6.1 ml per min was needed to achieve recording accuracy in the cervical esophagus. In the cervical esophagus, peristaltic complexes were higher in Amp (165 mm Hg) and shorter in Dur (2.6 sec) than in the thoracic esophagus. Data analysis revealed that recording fidelity is achieved at an IR which produces a pressure rise rate after catheter occlusion which equals or exceeds that of the pressure complex upstroke being recorded. The intraluminal transducers recorded pressure accurately under all conditions tested.