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Biomedical subjects

H M Hochberg

Publications and source records attributed to H M Hochberg.

At least 19 recordsLinked to original sources
PubMed1991

Continuous intrapartum measurement of tissue pH of the human fetus using newly developed techniques.

Using a fiberoptic probe with a dye indicator, pH was studied in a group of 124 fetuses. Acidotic tissue pH was found to be a far more powerful indicator of fetal, neonatal and maternal problems than acidotic capillary blood pH. The tissue pH related more consistently to obstetric problems throughout labor. A comparison was made of the reliability of fetal acidotic tissue pH and acidotic capillary blood pH data in the identification and prediction of obstetric problems.

Acid-Base Equilibrium↗
PubMed1985

Observations on perinatal heart rate monitoring. II. Quantitative unreliability of Doppler fetal heart rate variability.

Fifty-three fetal heart rate (FHR) tracings obtained by direct ECG monitoring during labor and 24 simultaneous external Doppler FHR tracings were analyzed for the quantitative assessment of baseline FHR variability. The beat-to-beat difference in FHR subsumed by 90% of all beat-to-beat changes within a tracing was taken as the index of variability of that tracing. This index correlated well with the visual assessment of variability for both internal ECG records (Spearman rank correlation coefficient, rs, = 0.71) and external Doppler records (rs = 0.78). However, there was no correlation between the variability index of the Doppler FHR records and that of simultaneous ECG FHR records (r = 0.11, p greater than 0.6). This finding casts doubt on the use of the presence of "normal" FHR variability as a sign of fetal well-being during antepartum FHR monitoring with current Doppler equipment.

Electrocardiography↗
PubMed1978

A study of the pH monitor in cats.

A study of the accuracy of the tpH electrode was performed in 10 cats. Hypoxia and acidosis were produced by ventilatory means and bicarbonate infusions were used to elevate the pH . Tissue pH correlated well with arterial (r = 0.9) within the physiological rates of change of pH. Prolonged tissue acidosis lead to eventual death. The correct and stable mechanical fixation of the pH electrode is a critical factor in assuring accurate results. The ROCHE tpH electrode accurately reflects arterial pH, and a correlation coefficient of at least 0.85 should be attainable in the human fetus.

Animals↗
PubMed1978

New instrument developments for fetal pH monitoring.

Recent technical improvements in the ROCHE fetal pH monitor have simplified its use and increased the proportion of useful and accurate recordings. These improvements include electronic changes to reduce static electricity, a new spiral electrode which stabilizes the pH electrode in the fetal scalp, improved incision tools, simplified applicator tools, and a total system for reducing pH electrode handling during calibration.

Electrodes↗
PubMed1978

Multicenter clinical trials of fetal pH monitoring in the U.S.A.

A multicenter collaborative study of the safety and clinical efficacy of the ROCHE fetal pH monitor has been started. A common protocol and reporting forms are used. As of April, 1978, 115 case reports have been received describing results with the latest hardware. The tissue pH monitor can be relied upon to monitor pH if the values are in the normal range. Comparison of tissue pH (tpH) with 146 capillary pH samples revealed 98% accuracy of tpH in classifying normal (greater than or equal to 7.20), but false tpH acidosis occurred in 6% of normals. Therefore, acidotic tpH values must be verified. Although six infants had some degree of trauma (small lacerations), there were no serious or permanent injuries.

Acidosis↗
PubMed1978

Evaluation of continuous monitoring of tissue pH in cats.

An improved continuous tissue pH monitoring system, designed for human subcutaneous fetal scalp tissue, was evaluated in 10 cats for total of 60 hours. Respiratory acidosis was induced with and without hypoxia to model the pathology of human clinical fetal distress. Arterial and venous pH were sampled every 15 minutes and the values were compared to those from the pH monitor system. The values paralleled arterial and venous blood pH, with correlation coefficients up to 0.98 under various pathologic acidotic conditions.

Animals↗
PubMed1978

Variable range directional doppler and abdominal ECG for FHR monitoring.

Antepartum nonstress fetal heart rate (FHR) monitoring may become a valuable screening tool for all pregnancies. Two methods proposed for an antepartum FHR monitor are examined: abdominal electrocardiogram (AECG) and variable range directional Doppler (RDD). A good quality (detailed, clearcut baseline) RDD FHR record was obtained in 74/75 (99%) examinations, and a good quality AECG record was obtained i31/75 (41%). Each patient was monitored in the supine, lateral and sitting positions. Considering all positions, 76% of the RDD records and 19% of the AECG records were good. The RDD system was efficacious for routine, clinical antepartum FHR monitoring, but the performance of the AECG was too limited for this purpose.

Doppler Effect↗
PubMed1978

Microfilm storage of fetal monitoring records: a practical solution.

Microfilming of fetal monitoring records has, at our institution, been found to be a practical method for storage of recording papers from fetal monitoring. This system permits a reduction of the records by a factor of 20:1 and up to 7.64 hours of fetal monitroing records will fit into a 4 x 6 inch film jacket. This microfilm record can easily be placed into a patient's chart and can thus easily be retrieved.

Fetal Monitoring↗
PubMed1978

FHR monitoring.

Explore the source record for details and available documents.

Amniocentesis↗
PubMed1978

Technical aspects of ranged directional doppler: a new doppler method of fetal heart rate monitoring.

A new technique for clarifying the fetal heart Doppler signal (Ranged Directional Doppler) for fetal heart rate (FHR) monitoring has been developed. Ranged Directional Doppler enhances the signals of interest and, in addition, permits a separation of the Doppler signals generated by fast-moving structures of the fetal heart either toward or away from the transducer. The separation of the Doppler signals provides increased clarity and reduced baseline clutter. These Doppler signals may approach the fetal scalp ECG in signal-to-noise ratio, and they may provide a signal that allows more accurate external monitoring of long-term and short-term variability patterns of the FHR.

Doppler Effect↗
PubMed1978

Observations in perinatal heart rate monitoring. I. A quantitative method of describing baseline variability of the fetal heart rate.

Simultaneous magnetic tape recordings of fetal scalp ECG, maternal ECG and uterine contractions were obtained from 23 patients in active labor. Computer-derived distributions of beat-to-beat changes were used to develop a simple numerical and graphical description of the long and short-term variability patterns. The visually observed variability may be described by the R-R interval change (beat-to-beat change), which is greater than 90% of the total number of beat-to-beat changes. Thus, the 90th percentile of R-R interval changes quantitatively describes the baseline variability. The variability may be classified as fixed, minimal, moderate or marked, based on this simple calculation. Graphs of cumulative percentage of R-R interval changes provide additional visual information. The effects of meperidine HCl on the observed variability were easily detected and visualized by these methods.

Electrocardiography↗
PubMed1976

Evaluation of the accuracy of a new ultrasonic fetal heart rate monitor.

An indirect Doppler fetal monitoring system has been developed and validated by computer comparison of simultaneous fetal heart rate (FHR) with Doppler and scalp ECG of high-risk patients during labor. The difference in measurement of FHR averaged 0.3 b.p.m., and 93 per cent of the Doppler FHR measures were within 10 b.p.m. of the ECG FHR. If interinstrument difference is discounted, 96 per cent were within 10 b.p.m. All types of decelerations and variability were well approximated. Doppler FHR from the instrument described may be relied upon as valid clinical information and may be obtained from over 90 per cent of labor patients with 93 per cent accuracy.

Doppler Effect↗
PubMed1976

An improved data display system for fetal heart rate monitoring.

Fetal heart rate (FHR) monitor records, particularly those derived from external sensors, may contain artifactual information closely resembling true FHR patterns. Additional machine-determined information may be used to help discriminate these data. Present commercial systems for indicating potentially artifactual FHR modify the FHR display, and this tends to cause the physician to ignore the absence of data or annoy him by obliterating some useful as well as potentialy useless information. Therefore, we chose to put the information that the data may be artifactual on another channel and allow the physician, rather than the instrument, to modify the interpretation of the FHR as necessary. A computer study was made of the characteristics of FHR beat-to-beat changes during poor signal to determine the most appropriate criteria for indicating when the FHR record is highly likely to be artifactual. Unphysiologic, erratic FHR changes are easily flagged by the presence of 3 serial beat-to-beat changes greater than 25 beats/min. Clinical testing demonstrated that this system allows the physician to better discriminate between valid and invalid data and increases the amount of usable data, particularly in active patients.

Data Display↗
PubMed1976

Fetal paroxysaml supraventricular tachycardia recorded by intrauterine scalp electrocardiography.

Fetal and neonatal paroxysmal supraventricular tachycardia (PST) requires attention because it may be associated with cardiac pathology and neonatal demise. Continuous monitoring of fetal heart rate and the ability to record clearly interpretable electrocardiograms from fetal scalp electrodes makes discovery and diagnoses of these fetal arrhythmias relatively simple. This report describes the discovery of this arrhythmia during routine DOPPLER ultrasound fetal monitoring and its documentation as PST by fetal scalp electrocardiography. (Fig. 1) The fetal heart rate during PST was 300 BPM, higher than previously reported. In contrast to previous reports, it did not appear post-natally and no pathology was found. Although the significance of transient fetal PST is not known, prudence indicates close observation of the neonate. This case demonstrates the value of fetal monitoring for the discovery, diagnosis and documentation of fetal arrhythmias during labor.

Delivery, Obstetric↗