Evolution of Esophageal Motility Testing: From Kronecker to Clouse

Esophageal motility, the science of quantifying the mechanical function of the esophagus, was initiated by Hugo Kronecker in Germany in 1882. Little progress was made until after World War II, when motility studies began in the Mayo Clinic and Boston University. After 1960, several key figures promoted the science, including Lauran Harris, Don Castell, Jerry Dodds, Tom DeMeester, Peter Kahrilas, and Ray Clouse. All were inspirational teachers and mentors as well as scientists. The technical developments from balloons and perfused catheters to the current solid-state catheters and sophisticated software has provided insights which have helped physicians to treat patients with dysfunction of the esophagus with increasing success.

The esophageal manometry with gas-perfused catheters

BackgroundThe well-established methods for esophageal manometry have some disadvantages: the-water-perfused catheters needs calibration by gravity and measuring in supine position, and the solid-state catheters are very expensive. Manometry using gas-perfused catheters is a suitable alternative. There have been only a few publications about this.Objectives and methodsThe results for esophageal manometry in 1700 patients were retrospectively analyzed based on the clinical reports and the manometry data. The gas-perfusion manometry was critically assessed.ResultsThe mean age was 54 years. The indications for esophageal manometry were GER symptoms in 58.5% (pathological DeMeester score in 41.8%), dysphagia in 12.4%, and already known achalasia in 8.9%. Motility disorders could be found in 40% of the patients with GER symptoms (51% of the patients with pathological DeMeester score), and in 88% of achalasia patients. The resting LES pressure was 8.9±5.94 mmHg with GER symptoms, 16.4±12.79 mmHg without GER symptoms, and 26.8±14.03 mmHg with achalasia. The relaxation LES pressure was 20.0±10.93 mmHg in achalasia patients, and 8.3±5.77 mmHg in the others.The gas-perfusion manometry was well tolerated by all patients without any serious complications.DiscussionManometry using gas-perfused catheters is an easy to handle and inexpensive method to investigate the esophageal motility. The suitability of gas perfusion with helium for esophageal manometry depends on physical and technical requirements, such as a constant gas flow, a dead space in the transducer, and the catheter being as small as possible. In consideration of this, the detection of the pressure changing in swallowing acts is excellent. The measured LES pressures are generally lower than with other methods like with water-perfused or solid-state catheters, possibly because of the higher compliance in a gas-filled surrounding. The normal values in gas-perfusion manometry are comparable but not identical with the values of other manometric methods.

Microdialysis in human skeletal muscle: effects of adding a colloid to the perfusate

Microdialysis catheters (CMA-60 with a polyamide dialysis membrane; 20,000-molecular wt cutoff) were either immersed in an external medium or were inserted in the quadriceps femoris muscle of healthy subjects, using perfusate with or without dextran 70. Varying the position of the outflow tubing induced changes in hydrostatic pressure. The sample volumes were significantly smaller in catheters perfused without a colloid compared with those perfused with a colloid [11–50% (in vitro) and 8–59% (in vivo) lower than in colloid-perfused catheters with the same position of the outflow tubing]. The sample volumes were also significantly smaller when the dialysis membrane was influenced by maximal hydrostatic pressure (above position) compared with minimal hydrostatic pressure (below position) [7–38% (in vitro) and 3–46% (in vivo) lower than in catheters in the below position with the same perfusion fluid]. In vivo, glucose concentration at a perfusion flow rate of 0.33 μl/min was higher when the catheters were perfused without a colloid [18–28% higher than in colloid-perfused catheters with the same position of the outflow tubing ( P < 0.001)] than with a colloid. A corresponding difference also tended to occur with lactate, glycerol, and urea. At 0.16 μl/min, the glucose concentration was the same irrespective of whether fluid loss had been counteracted by colloid inclusion or by lowering of outlet tubing. The mechanism behind the observed concentration difference is thought to be a higher effective perfusion flow rate when fluid loss is prevented at low-perfusion flows. This study shows that fluid imbalances can have important implications for microdialysis results at low-perfusion flow rates.