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Biomedical subjects

E H Hon

Publications and source records attributed to E H Hon.

At least 37 records · Page 2Linked to original sources
PubMed1976

Quantitation of uterine activity in 100 primiparous patients.

An on-line technique for quantitating uterine activity by measuring the total area under the intrauterine pressure curve was utilized during the labor of 100 primiparous patients. Uterine activity was measured in uterine activity units (1 UAU=1 Torr minute). UAU's were calculated for each patient in both cumulative and noncumulative fashions. The rate of uterine activity (UAU per unit of time) increased as labor progressed, yet the total UAU's expended at each centimeter of dilatation progressively decreased with advancing dilatation. Thus, the rate of cervical dilatation increased faster than could be accounted for by the increase in uterine activity. The implication being that the efficiency of uterine contractions increases with advancing labor. It no longer appears reasonable to refer to labor in terms of elapsed time. Information regarding the "pattern of cervical dilatation" and uterine activity appears to be much more meaningful to the evaluation of progress in labor. Quantitation of uterine activity may provide useful information for the ongoing management of labor. Quantitation of UA does provide a means of evaluating the effects of specific events such as medication, anesthesia, and manipulation on UA.

Adolescent↗
PubMed1976

Effects of ritodrine hydrochloride on uterine activity and the cardiovascular system in toxemic patients.

The effects of ritodrine hydrochloride were evaluated in 25 toxemic patients in active labor utilizing continuous electronic monitoring of fetal and maternal cardiovascular systems and uterine activity. Fetal scalp blood and free flowing maternal antecubital venous blood was obtained for pH, Po2, Pco2, base deficit and blood glucose determinations prior to and immediately following the study period. The initial ritodrine dose was 50 mug/min for 15 minutes. The dose was increased by 50 mug/min each 15 minutes until there was a clinically apparent reduction in uterine activity. Once this was accomplished, the infusion was maintained for 30 minutes. There was a consistent increase in the maternal heart rate (MHR) and a significant rise in fetal heart rate (FHR) late in the infusion and in the postinfusion period. There was a widening of the maternal pulse pressure mainly due to a reduction in diastolic pressure with little change in the mean blood pressure. Maternal and fetal pH decreased and base deficit increased during the study although the PO2 and PCO2 remained unchanged. Maternal and fetal blood glucose rose significantly following ritodrine infusion.

Blood Glucose↗
PubMed1976

The effect of drugs on uterine activity.

Uterine activity was measured for a 30-minute preinjection period and a 30-minute postinjection period for six drugs commonly used in labor. Uterine activity was quantitated by measuring the area below the uterine pressure curve with an on-line technic utilizing a voltage control oscillator. Uterine activity readings were obtained every 2.5 minutes and reported in uterine activity units (UAU). Unmedicated labor demonstrated a relatively static increase in UAU per unit of time in labor. On comparing total UAU before and after injection, only magnesium sulfate was noted to cause a decrease in total UAU. Utilizing 10-minute summations of UAU, the pre- and postinjection periods were compared to the calculated expected UAU for the 30 minutes following the preinjection period (assuming no drug had been used). For each of the other drugs, the positive slope of the calculated expected UAU shifted to a negative slope of the actual observed UAU following drug administration.

Adolescent↗
PubMed1975

Clinical fetal monitoring. VII. The evaluation and significance of intrapartum baseline FHR variability.

The clinical usage of intrapartum fetal monitoring has increased dramatically in the past few years. Understanding of the pathophysiologic significance of FHR patterns has been further elucidated, but quantitation and prediction on an individual basis at times present a practical clinical dilemma. Baseline FHR variability was evaluated in order to see if it provided additional commentary on fetal status. The presence of FHR variability appears to be a favorable commentary regarding both fetal and newborn status. A clinical method of apprasing FHR is presented and the significance of FHR variability suggested.

Apgar Score↗
PubMed1975

Significance of meconium during labor.

Continuous fetal heart rate (FHR) monitoring and routine fetal scalp blood sampling was utilized in the evaluations of 366 fetuses during labor. One hundred and six patients had meconium in the amniotic fluid at some time during labor. A total of 26,110 uterine contractions were monitored during these 366 labors. The incidence of FHR patterns as a percentage of uterine contractions was calculated for the meconium and nonmeconium groups. Although there was a 3 1/2-fold increase in the incidence of low five-minute Apgar scores (less than 7) in the meconium group, signs of fetal distress were, with rare esception, not significantly different from those in the nonmeconium group. The presence of meconium in the amniotic fluid without signs of fetal asphyxia (late decelerations and acidosis) is not a sign of fetal distress and need not be an indication for active intervention. The combination of fetal asphyxia and meconium staining of the amniotic fluid, however, does enhance the potential for meconium aspiration and a poor neonatal outcome. Universal fetal heart rate monitoring and appropriate fetal acid-base evaluation is recommended for following patients with meconium in the amniotic fluid during labor.

Acid-Base Equilibrium↗
PubMed1975

A study of fetal heart rate deceleration areas. II. Correlation between deceleration areas and fetal pH during labor.

Three FHR deceleration areas of fixed durations related to the onset of the concomitant uterine contraction were evaluated automatically with a small digital computer during labor. The correlations between these areas and the fetal scalp blood pH values were studied. The deceleration occurring 80 to 140 seconds after the onset of each uterine contraction during the 20 minutes preceding the fetal blood sampling presented the best correlation (r equals minus 0.453) with fetal pH values. In addition to FHR deceleration area, baseline FHR variability should be considered in predicting fetal condition.

Apgar Score↗
PubMed1975

Computer assessed fetal heart rate patterns and fetal scalp pH. A preliminary study.

From the beginning of biophysical and biochemical monitoring of the fetus during labor, a continuing attempt has been made to determine if a reliable correlation exists between these measurements and the well-being of the fetus. If such a correlation did indeed exist, the combined use of the two approaches would permit efficient, relatively simple fetal monitoring. This preliminary report describes the use of computer processed fetal heart rate patterns to predict fetal scalp blood pH. Initial results show a 90% overall accuracy in predictions; when corrected for some of the bias of retrospective predictions, the accuracy is 91% for high pH and 72% for low pH.

Blood Chemical Analysis↗
PubMed1974

Direct monitoring of arterial blood pressure in depressed and normal newborn infants during the first hour of life.

Direct systolic, diastolic, and mean arterial blood pressure was continuously recorded during the first 64 min of life in 150 newborn infants. The data were analyzed at 4, 8, 16, 32, and 64 min. The highest blood pressure values were noted during the first few minutes of life in all newborn infants, with a rapid drop within 4 to 8 min. Decline in blood pressure was more gradual throughout the remainder of the observation period. Blood pressures of depressed newborn infants at birth (Apgar scores 6 or less at 1 and 5 min) were compared to those of normal newborn infants (Apgar scores 7 or greater at 1 and 5 min). The former demonstrated generally higher systolic pressures during the first 16 min and diastolic pressures at 4 min when infants were compared by their 1 min Apgar scores and higher diastolic pressures at 4 min when the infants were compared by their 5 min Apgar scores.

Acid-Base Equilibrium↗