[Cardiotocographic monitoring of deliveries. A prospective comparative study of 2 types of electrodes]. / Kardiotokografisk fødselsovervågning. En prospektiv sammenlignende undersøgelse af to elektrodetyper.

The number of electrodes employed, the frequency of reapplication, the technical quality of monitoring and the complications of use of spiral electrodes and Copeland electrodes for cardiotocographic monitoring of deliveries are assessed in a prospective randomized investigation. The number of electrodes employed and the frequency of reapplications were significantly lower employing Copeland electrodes. Similarly, the electrode signal was significantly better as assessed by the percentage of the duration of monitoring in which the cardiotocogram did not register during the second stage of labour on account of poor electrode signals. No differences were found in the frequencies of complications or subjective discomfort in the mother on employing the two types of electrodes.

A rapid controller of temperature for use in determining Arrhenius profiles in biomembrane systems.

To minimize artifacts in temperature-velocity (Arrhenius) profiles due to aging of preparations of biological membranes, a rapid controller of temperature was developed for spectrophotometric or polarographic (02 electrode) measurements. The reaction mixture is cooled or heated through contact with Peltier elements. One Pt temperature sensor in the cuvette or electrode holder controls current flow into the Peltier units, and another Pt temperature sensor in the reaction mixture is used to read out the sample temperature on a meter or recorder, and to provide feedback control. The sample temperature can be reproducibly set to within 0.1 degree C, with a noise level of 0.04 degrees C or less; a change of 4 degrees C takes 1 min.

Measurement of fetal scalp pH by continuous-recording scalp electrode and correlation with capillary blood pH.

Experience with the use of a continuous-recording scalp electrode for fetal pH in subcutaneous scalp tissue is described. After initial problems, the correlation with capillary blood pH, taken by fetal scalp blood sampling, was found to be good, and it is concluded that this method is accurate enough to merit further trials in clinical practice. Residual technical problems remain which should not prove insurmountable.

A modified ion-selective electrode method for measurement of chloride in sweat.

A modified method of analysis of sweat chloride concentration with an ion-selective electrode is presented. The original method of sweat chloride analysis proposed by the Orion Research Corporation (Cambridge, Massachusetts 02139) is inadequate because it produces erratic and misleading results. The modified method was compared with the reference quantitative method of Gibson and Cooke. In the modified method, individual electrode pads are cut and placed in the electrodes rather than using the pads supplied by the company; pilocarpine nitrate (2,000 mg/l) is used in place of pilocarpine HCl (640 mg/l); sodium bicarbonate as the weak electrolyte is used instead of K2SO4. A 10-minute period for sweat accumulation is employed rather than a zero-time collection as in the original Orion method. The modification has been studied for reproducibility in individuals, reproducibility between right and left arm in individuals; it has been compared extensively with the quantitative method of Gibson and Cooke, both in normal individuals and in patients with cystic fibrosis. There is excellent agreement between the modified method and the quantitative reference method. There appears to be a slight bias toward higher concentrations of chloride from the right arm compared with the left arm, but this difference is not medically significant.

Construction of a thin film PO2-electrode using gold paste.

A thin film gold electrode for biological oxygen consumption was constructed using gold paste. This electrode is easy to construct, has high sensitivity and is disturbed only slightly by bubbling of the surrounding fluid. As an application, the electrode was used to measure oxygen consumption of the skin and yielded a reasonable value.

Dynamic palatometry.

A computer-based instrumental system is described for continuous palatometry. Thin pseudopalatal plates (approximately 0.2 mm) with embedded electrodes are used to detect linguapalatal contact during speech articulation. Geometric configurations of such contacts are then derived and displayed to reveal articulatory characteristics.

A coaxial electrode for intraocular diathermy.

A bipolar electrode was used in intraocular coagulation of vessels. This device was a useful adjunct for the coagulation of vessels in diabetic eyes undergoing vitrectomy. No surgical complications due to the diathermy occurred in the first six patients on whom the device was used.