ABSTRACT
A new catheter, provided with an Ion Sensitive Field Effect Transistor as a pH sensor and incorporating a reference electrode, was evaluated for esophageal pH recording. The pH-sensitivity was 54 mV/pH in vitro, with a linear response between pH 2 and pH 9. Clinical semi-ambulatory 24-hour esophageal pH recordings were carried out in 6 adults and 15 infants. System drift after 24-hour in vivo recording was 0.14 pH units +/- 0.10 pH units, and -0.01 pH units +/- 0.10 pH units, in pH 4.0 and pH 7.0 calibration solution, respectively, in the pediatric group (n = 15). It is concluded that the reusable catheter combines accurate esophageal pH monitoring with optimum patient comfort.
Subject(s)
Catheterization/instrumentation , Esophagus , Hydrogen-Ion Concentration , Monitoring, Physiologic/instrumentation , Adult , Child , Electrodes , Equipment Design , Evaluation Studies as Topic , HumansABSTRACT
Since blood pH reflects the metabolic state as well as the functioning of the respiratory and circulatory systems, it appears to be one of the vital parameters that should be continuously monitored. The point to point measurement of pH by sampling has limitations, since results are available after some time only. A continuous pH signal is necessary in rapidly changing situations such as often occur during intensive treatment. The application of ion-selective field-effect transistor (ISFET) technology to intravascular pH measurement seemed attractive since these devices offer a short response time, are suitable to miniaturization and fabrication in large quantities, and have a low output impedance. The system was tested in dog experiments. Two to four pH-ISFET catheters were tested simultaneously in each dog. Arterial samples for blood-gas analysis with a Radiometer ABL2 system were taken during periods in which plasma-pH was stable. Clinical trials were performed in patients who were admitted to the intensive care unit after coronary artery bypass grafting. Testing the pH-ISFET system in dogs (N = 12) and comparing it with ABL2 measured samples (n = 132 with a pH range of 6.72-7.86), resulted in a delta pH (ISFET-ABL2) of 0.016 +/- 0.024 pH with a maximum deviation of 0.06. The clinical trials proved that the system is well-suited for monitoring intravascular pH in critically ill patients.
Subject(s)
Blood Chemical Analysis , Hydrogen-Ion Concentration , Animals , Arteries , Catheters, Indwelling , Dogs , Evaluation Studies as Topic , Humans , Monitoring, PhysiologicABSTRACT
An arterial pH catheter was inserted into a femoral artery of 15 patients immediately after coronary artery bypass grafting. Catheter pH measurements correlated well with conventional blood gas measurements during the first 12 h postsurgery, and revealed rapid pH changes during weaning and bronchial suctioning. This device is a promising step in the development of a complete on-line blood gas analyzer.
Subject(s)
Acid-Base Equilibrium , Coronary Artery Bypass , Monitoring, Physiologic/instrumentation , Aged , Blood Gas Analysis/instrumentation , Catheters, Indwelling , Female , Femoral Artery , Humans , Male , Middle Aged , Postoperative Care/instrumentationABSTRACT
A case report is presented of a circumscribed neurofibroma in the external genitalia of a young girl which gave the impression of a phallus and a labioscrotal gonad. There was a large care-au-lait spot on the lower abdomen. An acute anxiety state developed which, together with the genital abnormality was corrected by clitoral and labial reduction.
