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Biomedical subjects

S L Clark

Publications and source records attributed to S L Clark.

At least 91 records · Page 5Linked to original sources
PubMed1986

Peripartum colloid osmotic pressures: correlation with serum proteins.

Colloid osmotic pressure is a principal regulator of capillary fluid exchange. Alterations in colloid osmotic pressure in preeclamptic patients, as well as significant peripartum changes in colloid osmotic pressure in normotensive patients, are reported. In a study of 72 normotensive and preeclamptic patients, peripartum colloid osmotic pressure, serum albumin, and total serum protein were compared. Both groups exhibited significantly lower colloid osmotic pressure in the postpartum period than that measured antepartum. The mean antepartum colloid osmotic pressure in preeclamptic patients was significantly lower than in normotensive subjects. Regression equations were calculated [colloid osmotic pressure = 5.21 (total serum protein) -11.4 (r2 = 0.851)] and [colloid osmotic pressure = 8.1 (serum albumin) -8.2 (r2 = 0.891)]. Within the physiologic ranges most commonly reported for normotensive and preeclamptic patients, the use of these equations allowed calculation of colloid osmotic pressure to within 10% of measured values in 75 and 80% of the cases, respectively. Where direct measurement of colloid osmotic pressure is not readily available, calculated values may be helpful in patient management.

Adolescent↗
PubMed1986

Antepartum reversal of hematologic abnormalities associated with the HELLP syndrome. A report of three cases.

The "HELLP syndrome" refers to the occurrence of thrombocytopenia, elevated liver enzymes and, at times, hemolysis in patients with preeclampsia. Although uncontrolled series have reported a reversal of thrombocytopenia and elevated liver enzymes with aspirin and colloid infusion, most authors recommend that delivery be done soon after the diagnosis is made. The abnormal laboratory parameters of the HELLP syndrome may be reversed completely with bed rest alone, and with preterm gestations, conservative management may be possible.

Adult↗
PubMed1985

Intrapartum fetal surveillance: the role of fetal scalp blood sampling.

Continuous electronic fetal heart rate monitoring and fetal scalp blood sampling have traditionally played a complementary role in intrapartum fetal surveillance. Nevertheless, biochemical assessment of fetal blood pH, with the use of scalp or umbilical cord blood, is often viewed as the "gold standard" against which biophysical indicators of fetal distress must be judged. In actual clinical practice, however, fetal scalp blood sampling is only rarely used. In addition, there is a growing body of evidence to suggest that, when properly interpreted, fetal heart rate assessment may be equal or superior to measurement of fetal blood pH in the prediction of both good and bad fetal outcomes. Under certain circumstances, fetal scalp blood sampling remains a valuable clinical tool; however, we recommend a deemphasis of fetal scalp blood sampling in general clinical practice. Both theoretical and practical considerations suggest that the properly trained clinician may pursue an approach for the detection of fetal distress that does not include scalp blood sampling without either compromising his ability to detect fetal distress or significantly increasing the cesarean section rate.

Apgar Score↗
PubMed1985

Labor and delivery in the presence of mitral stenosis: central hemodynamic observations.

During a 1-year period, eight patients with New York Heart Association Class III or IV mitral stenosis were studied throughout the peripartum period with a pulmonary artery catheter. All patients were delivered vaginally. Intrapartum management was based upon cautious diuresis for preload optimization and heart rate control with propranolol. A mean increase in pulmonary capillary wedge pressure of 10 mm Hg was observed in the immediate postpartum period. Only two patients demonstrated a significant increase in cardiac output during this same time period. Central venous pressure correlated poorly with pulmonary capillary wedge pressure in seven of eight patients. Neonatal outcome was uniformly excellent. With the management approach described, no patient exhibited deterioration of cardiopulmonary status during the peripartum period.

Adult↗
PubMed1985

Experience with the pulmonary artery catheter in obstetrics and gynecology.

Although traditionally the exclusive domain of other medical specialties, pulmonary artery catheterization may be of tremendous benefit to a variety of obstetric and gynecologic patients. Our experience with such invasive hemodynamic monitoring in 72 patients in an obstetrics and gynecology service is presented. In 86% of cases, catheter placement and primary management were carried out by residents in obstetrics and gynecology. Although many of the indications for pulmonary artery catheterization encountered are common to other areas of medicine, certain conditions such as severe preeclampsia or rheumatic heart disease in pregnancy involve pathophysiologic conditions unique to our specialty. On the basis of our experience, recommended indications for pulmonary artery catheterization in obstetric and gynecologic patients are presented. Insertion techniques, complications, and clinical outcome are discussed.

Cardiac Catheterization↗
PubMed1985

The role of external version in the intrapartum management of the transverse lie presentation.

External version under tocolysis was applied and studied prospectively as an alternative to routine cesarean delivery in the laboring patient with a transverse lie presentation. After sonographic confirmation and signing of informed consent, 12 patients with a transverse lie presentation and intact membranes agreed to participate in the current investigation. For these 12 patients, 10 (83%) presentations were successfully converted to a longitudinal lie (nine cephalic, one breech) and two (17%) remained transverse. Of the 10 patients with successful conversions, six (60%) delivered vaginally while four required cesarean delivery. In two (20%) patients external version was unsuccessful and both patients were delivered by cesarean. With the exception of one infant with congenital anomalies, neonatal outcome was excellent in the study population. Overall, the use of external version in the laboring patient with a transverse lie presentation was associated with a 50% reduction in the cesarean section rate. While these results are encouraging, further experience is still needed to more clearly define the maternal and fetal risks associated with this procedure.

Adult↗
PubMed1985

Hemodynamic alterations associated with amniotic fluid embolism: a reappraisal.

Experimental amniotic fluid embolism in animals produces profound pulmonary hypertension and acute cor pulmonale without evidence of left ventricular compromise. Authors reporting hemodynamic alterations associated with clinical amniotic fluid embolism have traditionally attempted to explain their findings within this experimental framework. A reanalysis of the five published cases of amniotic fluid embolism, which include hemodynamic data derived from pulmonary artery catheterization as well as a report of a sixth case suggests a hemodynamic interpretation different from the traditional one based on the animal model. Left ventricular failure is the only hemodynamic abnormality consistently observed in humans, and the published data are most readily explained on this basis alone. A theoretical model of hemodynamic changes accompanying amniotic fluid embolism that incorporates both experimental and clinical observations is presented. Therapeutic implications are discussed.

Adult↗
PubMed1985

Transient ventricular dysfunction associated with cesarean section in a patient with hyperthyroidism.

Pulmonary artery catheterization was performed prior to surgery in a severely hyperthyroid patient undergoing cesarean section. A transient but significant decline in left ventricular performance was observed in conjunction with the stress of operation. A parallel is suggested between this phenomenon and the documented exercise-induced reduction of left ventricular function in nonpregnant hyperthyroid patients.

Adult↗
PubMed1985

Hypogastric artery ligation for obstetric hemorrhage.

Ligation of the hypogastric arteries has been recommended for control of obstetric hemorrhage. However, specific information regarding its effectiveness is lacking. The hospital charts of 19 patients undergoing bilateral hypogastric artery ligation for the control of otherwise intractable obstetric hemorrhage were reviewed. Indications included uterine atony (15), lateral extension of a low-transverse uterine incision (three), and placenta accreta (one). This procedure was effective in controlling bleeding in eight of 19 patients (42%). Hysterectomy was necessary in the remaining 11 patients. In these patients, blood loss, operating time, and intraoperative morbidity was increased when compared with a group of 59 patients undergoing emergency hysterectomy for obstetric hemorrhage without prior ligation of the hypogastric arteries. Surgical approaches to hypogastric artery ligation are discussed.

Arteries↗
PubMed1985

Placenta previa/accreta and prior cesarean section.

To assess the relationship between increasing numbers of previous cesarean sections and the subsequent development of placenta previa and placenta accreta, the records of all patients presenting to labor and delivery with the diagnosis of placenta previa between 1977 and 1983 were examined. Of a total of 97,799 patients, 292 (0.3%) had a placenta previa. The risk of placenta previa was 0.26% with an unscarred uterus and increased almost linearly with the number of prior cesarean sections to 10% in patients with four or more. The effect of advancing age and parity on the incidence of placenta previa was much less dramatic. Patients presenting with a placenta previa and an unscarred uterus had a 5% risk of clinical placenta accreta. With a placenta previa and one previous cesarean section, the risk of placenta accreta was 24%; this risk continued to increase to 67% (two of three) with a placenta previa and four or more cesarean sections. Possible mechanisms and clinical implications are discussed.

Adult↗
PubMed1985

Preeclampsia/eclampsia: hemodynamic and neurologic correlations.

Three patients with eclampsia and four with severe preeclampsia underwent pulmonary artery catheterization before either labor or significant volume infusion. There was no difference in systemic or pulmonary vascular resistance, cardiac index, left ventricular stroke work index, or any other hemodynamic parameters between the eclamptic and severely preeclamptic patients. Despite the small numbers, plasma colloid osmotic pressures were significantly lower in the eclamptic patients. Factors other than the intensity of peripheral vasospasm may primarily affect the occurrence of grand mal seizures in patients with preeclampsia.

Adolescent↗
PubMed1984

The scalp stimulation test: a clinical alternative to fetal scalp blood sampling.

Intrapartum fetal heart rate response to various scalp stimuli and its correlation with scalp pH was studied in a prospective manner. One hundred fetuses with heart rate tracings judged by the resident responsible for the patient to be suggestive of fetal asphyxia were entered into the study. Each fetus was subjected to firm digital pressure on the head followed by a gentle pinch of the scalp with an atraumatic clamp. Scalp blood sampling was then performed in the usual manner. Response to either of these stimuli by an acceleration of the fetal heart rate of 15 bpm lasting at least 15 seconds was uniformly associated with a scalp blood pH of greater than or equal to 7.19. Fifty-one fetuses so stimulated responded with an acceleration. Of the remaining fetuses, 19 had a scalp pH less than 7.19 and 30 were associated with a pH greater than 7.19. Clinical application of such a scalp stimulation test could, therefore, reduce the necessity for scalp blood sampling by approximately 50% in the presence of a fetal heart rate pattern suggesting acidosis. Such a provocative test may also be very useful with an abnormal fetal heart rate pattern suggestive of acidosis when the cervix is sufficiently dilated to permit scalp blood sampling.

Female↗
PubMed1984

Emergency hysterectomy for obstetric hemorrhage.

From 1978 to 1982, 70 cases of emergency hysterectomy for obstetric hemorrhage were performed at Los Angeles County/University of Southern California Women's Hospital. Sixty hysterectomies followed cesarean section, and ten were performed for hemorrhage after vaginal delivery. The most common indication for hysterectomy was atony (43%) followed by placenta accreta (30%), uterine rupture (13%), extension of a low transverse incision (10%), and leiomyomata preventing uterine closure and hemostasis (4%). Hysterectomies performed for atony had a significant association with the following factors when compared to hysterectomies performed for other indications: 1) amnionitis, 2) cesarean section for labor arrest, 3) oxytocin augmentation of labor, 4) MgSO4 infusion, and 5) fetal weight. Fifty-seven percent of hysterectomies performed for placenta accreta were associated with a previous cesarean section. During the study period, 53% of all patients presenting at term with both a placenta previa and one or more previous cesarean sections, subsequently underwent hysterectomy for placenta accreta. Even with a broad inclusion of risk factors, only 74% of patients developing a hemorrhagic complication leading to hysterectomy can be identified before delivery.

Cesarean Section↗