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Biomedical subjects

K S Koh

Publications and source records attributed to K S Koh.

13 recordsLinked to original sources

R--pulse wave timing: a technique for continuous cardiovascular monitoring in obstetrics--preliminary report.

A simple, noninvasive technique for continuous cardiovascular monitoring in obstetrics using R--pulse wave timing is described. This preliminary study suggests that different maternal heart rate/R pulse patterns are found in different clinical circumstances. A significant decrease in the R pulse interval occurred in the third trimester in both normal and diabetic women in the left lateral position when compared to the supine position. The R pulse intervals were all prolonged in the standing position in both gravid and nongravid women. During labor R pulse interval usually shortened during uterine contraction. Prolongation of R pulse interval was observed during thiopental injection, hypotension, and excessive bleeding at cesarean section. Exercise testing in healthy male subjects suggested that the change in R pulse interval becomes constant when the oxygen consumption rate reaches a plateau at 100% maximal work load. Further extensive clinical study appears worthwhile since it may add another dimension to cardiovascular monitoring and give an early indication of cardiovascular reserve.

Anesthesia, Obstetrical

Obstetric factors influencing outcome in infants weighing from 1,001 to 1,500 grams.

The neonatal mortality rate has dramatically improved in recent years. Occurrence of these losses is concentrated in low-birth-weight infants. At Los Angeles County-University of Southern California Medical Center, the infants weighing less than 1,500 grams contribute two thirds of neonatal deaths, although they may represent only 1.5 per cent of total births. Such observations have led to the evaluation of obstetric factors as they relate to the outcome in the low-birth-weight infants weighing from 1,001 to 1,500 grams. Retrospective evaluation of 201 low-birth-weight-infants' charts demonstrated a tendency by the obstetrician to clinically underestimate fetal weight. In cases where fetal estimated weight and measured birth weight correlated, the mortality rate was 20 per cent; in cases of underestimation, the mortality rate rose to 50 per cent. Other obstetric factors evaluated were the use of FHR monitoring, the method of delivery, and the significance of the Apgar score.

Apgar Score

The changing perinatal and maternal outcome in chorioamnionitis.

Chorioamnionitis is difficult to detect clinically, but its recognition in those at risk is essential. A retrospective study of 140 patients from among 26,129 deliveries was conducted over a 2-year period. The findings suggest that in modern obstetric practice, both perinatal and maternal complications associated with chorioamnionitis (particularly sepsis) are infrequent problems. Four neonatal deaths occurred but no infants died of sepsis. There were no maternal deaths, but 38 patients developed postpartum infections. Cesarean section did not appear to improve either perinatal or maternal outcome. With the use of appropriate modern antibiotics, extraperitoneal cesarean section and cesarean hysterectomy are probably no longer indicated. Not all neonates born out of a microbiologically contaminated intrauterine environment required antibiotic therapy, however, and individualization is recommended.

Amnion

Electromechanical intervals of the fetal cardiac cycle.

The measurement of electromechanical intervals of the fetal cardiac cycle may be useful in the evaluation of cardiac status, since they are based upon sound physiological principles. Studies of EMIs in the human fetus are currently in their infancy and clinical evaluation of their usefulness awaits the development of adequate data acquisition, reduction and analysis techniques.

Animals

Changes in fetal heart rate-uterine contraction patterns associated with eclampsia.

Eclamptic seizures have been associated with fetal bradycardia and rapid onset or progression of labor. The fetal heart rate (FHR)-uterine contraction patterns during 14 seizures in 10 eclamptic patients were studied. Some seizures occurred in patients in whom magnesium sulfate levels were in the therapeutic range. The FHR response during an eclamptic episode was generally prolonged bradycardia. Uterine activity was noted to increase during seizure activity and preceded the fall in FHR. As seizure activity subsided, uterine hyperactivity diminished and the FHR rose, frequently demonstrating compensatory tachycardia. The clinical implications and possible pathophysiologic mechanisms of the FHR-uterine contraction observations are discussed.

Adolescent

Massive intestinal infarction in young women: complication of use of oral contraceptives?

Massive intestinal infarction due to occlusion of the celiac, superior mesenteric and inferior mesenteric arteries occurred in two young women, one of who subsequently died. Both were smokers. They had ingested oral contraceptives for 5 and 8 years, respectively, but this therapy could not be proven to be a causative factor in their ischemic bowel disease; although such an association is uncommon, it should be considered in young women with abdominal pain.

Abdomen, Acute

Fertility in women with gonadal dysgenesis.

A successful pregnancy in a patient with a 45,X/47,XXX karyotype who had premature menopause is described. Review of the literature revealed an additional 24 cases of fertility in women with gonadal dysgenesis associated with a 45,X chromosomal line. Their reproductive history showed a total of 58 pregnancies. However, abortion, stillbirth, and abnormal progeny, including five with chromosomal errors, were common. Therefore, such patients should be advised regarding their reduced fertility potential and the possibility of abnormal offspring.

Adult

Premature labour.

Prematurity is by far the commonest cause of neonatal morbidity and mortality. The management of premature labour is empirical because little is understood about the mechanism of labour. Effective uterine relaxant drugs have an important, albeit minor role. Phototherapy has reduced the complications of neonatal hyperbilirubinemia, and the beneficial effect of antepartum corticosteroid therapy in minimizing the risk of respiratory distress syndrome is now convincing. Prophylactic antibiotic therapy in premature rupture of the membranes does not alter perinatal mortality, although postpartum maternal morbidity is reduced. The introduction of neonatal intensive care units has improved the survival rate of premature infants. Sound clinical judgement remains the mainstay in the management of premature labour.

Adrenal Cortex Hormones

Fetal monitoring during maternal cardiac surgery with cardiopulmonary bypass.

Fetal cardiac activity was monitored with an external ultrasound transducer in two patients with clinical class III heart disease due to severe mitral stenosis complicated by pulmonary hypertension, undergoing open heart surgery with cardiopulmonary bypass in the 2nd trimester of pregnancy. Fetal distress was detected in one patient, who had mitral valvuloplasty, and was corrected by increasing the rate of blood flow, and the other patient had a mitral valve replacement but no fetal distress was noted. The postoperative course of both mothers and fetuses was uneventful.

Adult

Adenocarcinoma of the endometrium in a teenager.

Endometrial carcinoma developed in a teenager with obesity, hypertension, hyperestrinism and lack of diurnal variation of plasma cortisol concentration. She underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy and is receiving estrogen therapy. Her six obese sisters and her mother, who are at risk for endometrial carcinoma, are being managed conservatively.

Adenocarcinoma

Experience with fetal monitoring in a university teaching hospital.

Fetal monitoring during labour may be expected to decrease perinatal losses and the number of infants born with brain damage. In a prospective study of intrapartum fetal monitoring in selected high-risk pregnancies in a Winnipeg hospital the monitoring rate was 26.5% and the cesarean section rate in the monitored group was 22.0%. The fetal outcome in the monitored group was better than in the unmonitored group. The establishment of a fetal intensive care unit is believed to be strongly desirable in improving fetal surveillance during labour. Fetal monitors should be stationed in the delivery room as well as in the first-stage room.

Delivery, Obstetric