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Biomedical subjects

J C Morrison

Publications and source records attributed to J C Morrison.

At least 109 records · Page 6Linked to original sources
PubMed1996

Forceps and vacuum delivery: a survey of North American residency programs.

OBJECTIVE: To document resident instruction in operative vaginal delivery by forceps and vacuum. METHODS: A survey was sent to all 291 obstetrics-gynecology training programs in the United States and Canada. RESULTS: The overall response rate was 72% (210 of 291). Most programs (60%) have an operative vaginal delivery rate of 10% or less. Nearly all of the responding programs (199 of 209, 95%) teach operative vaginal delivery via the vacuum route; metallic cups are used in only 14% of centers. Forceps are the primary instrument in most programs (68%), but nearly one-third of responding centers use the vacuum method more often than forceps. Instruction in midpelvic operative vaginal delivery is offered in 64% of the programs, with forceps being more common by nearly a two-to-one ratio. Deep transverse arrest is handled initially by forceps by half of the respondents, whereas 28 and 22% would proceed with cesarean or attempt a vacuum extraction, respectively. CONCLUSION: Instruction in both types of operative vaginal delivery is found in most programs. The forceps are used more commonly, but vacuum is the preferred instrument in about one-third of training programs. Instruction in midpelvic delivery is offered in 64% of programs, but we noted a declining trend.

Canada↗
PubMed1996

A randomized prospective trial of the obstetric forceps versus the M-cup vacuum extractor.

OBJECTIVE: Our purpose was to determine the efficacy of the obstetric forceps versus the M-cup, a new vacuum extractor cup, and maternal-neonatal complication rates. STUDY DESIGN: Over a 10-month period operative vaginal deliveries were randomized between the obstetric forceps and the M-cup vacuum extractor cup. Maternal demographics, indication for intervention, analgesia, position, station, degree of asynclitism, fetal caput-molding, and time from application to delivery were prospectively recorded. Episiotomy and extensions, lacerations, and the reason for abandonment of the randomized instrument were noted in both groups. Fetal weight, Apgar scores, cord arterial gases, hyperbilirubinemia, phototherapy, and any evidence of fetal trauma were documented at delivery or in the nursery. RESULTS: Six hundred thirty-seven women were randomized, 315 in the forceps group and 322 in the M-cup group. There were no differences in maternal demographic variables. The station, position, degree of asynclitism, or requirement for rotation was not different between the groups. The corrected efficacy rates were forceps 92% and M-cup 94% (p = 0.217). The M-cup deliveries were accomplished more rapidly than forceps deliveries (p < 0.001) and were associated with a lower rate of episiotomy (p < 0.001), third-degree (p < 0.001) and fourth-degree (p = 0.002) lacerations, but blood loss as clinically estimated (p = 0.232) or as measured by hemoglobin levels (p = 0.166) was not significantly different. Forceps deliveries were associated with fewer clinically diagnosed cephalhematomas (p = 0.015) than M-cup deliveries were, but there were no differences in the number of neonates diagnosed with hyperbilirubinemia (p = 0.377) or in the number of infants treated with phototherapy (p = 0.660). CONCLUSIONS: The M-cup vacuum extractor cup appears to be as efficient (and faster) than the obstetric forceps but is associated with significantly more fetal cephalhematomas, whereas maternal injuries are more common with the forceps.

Adult↗
PubMed1996

A pilot study of intravenous ondansetron for hyperemesis gravidarum.

OBJECTIVE: We attempted to determine whether the antiemetic ondansetron would be more effective than promethazine in treating hyperemesis gravidarum. STUDY DESIGN: Patients with hyperemesis gravidarum who required hospital admission were randomized to receive either intravenous ondansetron (n = 15) or intravenous promethazine (n = 15) in a double-blind manner. Severity of disease was determined by electrolyte status, weight loss, ketonuria, and prior use of outpatient antiemetics. Outcome variables included degree of nausea, weight gain during treatment, days of hospitalization, and number of medication doses. RESULTS: In this preliminary investigation ondansetron offered no advantage when compared with promethazine in the relief of nausea, weight gain, days of hospitalization (4.5 +/- 2.3 vs 4.5 +/- 1.5), and total doses of medication per hospitalization (2.1 +/- 1.2 vs 1.9 +/- 1.3). CONCLUSION: This preliminary trial of ondansetron demonstrated no benefit over promethazine in patients hospitalized for hyperemesis gravidarum.

Adult↗
PubMed1996

The clinical efficacy of oral tocolytic therapy.

OBJECTIVE: Our purpose was to determine whether maintenance oral tocolytic therapy after preterm labor stabilization decreases uterine activity, reduces the rate of recurrent preterm labor and subsequent preterm birth, or improves neonatal outcome. STUDY DESIGN: Women with documented idiopathic preterm labor stabilized with acute tocolytic therapy were randomized to three groups: placebo, terbutaline 5 mg, or magnesium chloride 128 mg, all given orally every 4 hours. Patients and providers were blinded to group assignment. All subjects were enrolled in a comprehensive system of preterm birth prevention that included preterm labor education, weekly clinic visits, home uterine contraction assessment, daily phone contact, and 24-hour perinatal nurse access. RESULTS: Of the 248 patients who were randomized, 39 were delivered before discharge and 4 were lost to follow-up, leaving 205 for final analysis: 68 placebo, 72 terbutaline, and 65 magnesium. The terbutaline group had significantly more side effects than the placebo group did. All groups had otherwise similar perinatal outcomes when confounding variables were controlled for. Overall, the three groups had a preterm birth rate < 37 weeks of 55.6% delivery, < 34 weeks of 15.6%, a 20.4% rate of newborn intensive care unit admission, and a mean neonatal length of stay of 6.3 days. CONCLUSIONS: Maintenance oral tocolytic therapy did not decrease uterine activity, reduce the rate of recurrent preterm labor or preterm birth, or improve perinatal outcome. Overall improvement in perinatal outcome may be achieved with a comprehensive program of preterm birth prevention without the use of maintenance oral tocolytic therapy.

Administration, Oral↗
PubMed1996

Lowering the threshold for the diagnosis of gestational diabetes.

OBJECTIVE: Our purpose was to determine whether lowering the diagnostic threshold for gestational diabetes mellitus on 3-hour 100 gm oral glucose tolerance testing will select a population at risk for adverse perinatal outcome. STUDY DESIGN: In this retrospective study 434 patients with an abnormal 50 gm glucose screen result (> or = 140 mg/dl) underwent a standardized 3-hour oral glucose tolerance test. The results were stratified according to maternal weight and the criteria recommended by Sacks or Carpenter. Birth weight and rate of macrosomia were the primary perinatal outcome variables analyzed. RESULTS: Analysis of the data set stratified according to the Sacks criteria revealed results very similar to the Carpenter criteria data set. Patients who would have been newly diagnosed with gestational diabetes mellitus only if the lowered criteria were used (group 2) were older and heavier. No other variable comparisons achieved statistical significance. When the same patients were stratified according to prepregnancy weight, overweight patients were older, gained less weight during the third trimester, underwent cesarean section more often, and had higher cumulative maternal morbidity. Regression analysis showed that the degree of hyperglycemia did not predict macrosomia or influence birth weight, but prepregnant maternal body mass index was associated with macrosomia. CONCLUSIONS: Fetal macrosomia is influenced by maternal prepregnant body mass index. Lowering the glucose tolerance test threshold would result in overdiagnosis of gestational diabetes mellitus without improving perinatal outcome.

Birth Weight↗
PubMed1996

Operative vaginal delivery: a survey of fellows of ACOG.

OBJECTIVE: To document operative vaginal delivery rates of ACOG Fellows and to stratify practice patterns with regard to mid-pelvic delivery and deep transverse arrest by the time elapsed since residency. METHODS: A survey was mailed to a random sample of 1600 ACOG Fellows. Of the 597 respondents (37%), 558 who still practice obstetrics formed the study group. Selection bias regarding recipients of the survey was reduced by randomization by an uninvolved third party. The length of time since residency was categorized as 10 years or fewer ("recent," 31%), 11-20 years ("intermediate," 43%), and more than 20 years ("remote," 26%). RESULTS: The majority of respondents (338 of 558, 61%) reported an operative vaginal delivery rate of 15% or less. One hundred forty-two (25%) use only forceps, whereas 78 (14%) use vacuum extraction exclusively. More than half have abandoned mid-pelvic operative vaginal deliveries, and of the 41% who still perform these operations, about half use forceps. In cases of deep transverse arrest, about 25% perform cesarean delivery, whereas 26% and 42% use forceps or vacuum, respectively. Resident training and practice in vacuum delivery were more common in the recently trained groups (recent > intermediate > remote; P < .001). There were no differences among the groups with respect to attempting mid-pelvic operative vaginal delivery (P = .29), but the remote group was more likely to use forceps, whereas the recent group was more likely to use vacuum (P = .039). A large disparity existed among the groups regarding the management of deep transverse arrest, with vacuum use associated with group assignment (P < .001). CONCLUSIONS: The majority of respondents have an operative vaginal delivery rate of no more than 15%. Most respondents have abandoned mid-pelvic operative vaginal delivery. Practice patterns reflect differences in residency training; the more recently trained Fellows more often were taught and use vacuum for delivery.

Data Collection↗
PubMed1996

Circadian rhythm of intraocular pressure in the rat.

To define the characteristics of the diurnal variation of intraocular pressure (IOP) in eyes of awake rats, ten male brown Norway rats were entrained to a 12-hour light:12-hour dark (12L:12D) lighting schedule and were conditioned to IOP measurement with the TonoPen XL tonometer while awake, using only 0.5% proparacaine HCl anesthesia. The IOP measurements were performed in 4 experiments: Preliminary-IOP was measured at 6-hour intervals in both eyes of each animal, to determine correlation between right and left eyes; Light:Dark-lighting remained the same as in the preliminary experiment, but the measurement schedule was altered so that measurements were obtained at 4-hour intervals in alternating eyes, over two 24-hour light cycles; Dark:Dark-animals were placed in constant dark (0L:24D) and, after 72 h, measurements were obtained at 4-hour intervals in alternating eyes. Animals were then re-entrained to the previous 12L:12D schedule for 7 days, after which they were returned to constant dark and the experiment was repeated; and Dark:Light-animals were entrained to a reversed light:dark cycle (12D:12L) for 28 days, after which measurements were obtained in the same fashion as in the Light:Dark experiment. Close agreement was found between right- and left-eye IOPs. Animals on a 12L:12D schedule exhibited lowest IOP while the lights were on (19.3 +/- 1.9 mm Hg), and highest (31.3 +/- 1.3 mm Hg) while the lights were off. Pressure changes anticipated the change from light to dark and dark to light. This pattern persisted in constant dark, and was reversed when the cycle was changed to 12D:12L. Brown Norway rats possess a regular rhythm of IOP that is entrained by the cycle of light and dark, and persistence of this rhythm in constant dark establishes it as a circadian rhythm. Furthermore, our results indicate that reliable and physiologically meaningful IOP measurements can be obtained in awake rats using the TonoPen XL tonometer.

Animals↗
PubMed1996

Order of rotation in third-year clerkships. Influence on academic performance.

OBJECTIVE: To determine if student performance during the third-year clerkship is influenced by the order of departmental rotation. STUDY DESIGN: In this retrospective, descriptive study, the National Board of Medical Examiners (NBME) scores, departmental examination grade (DE) and final block grade (FG) were stratified into six segments based on the order of block time in obstetrics-gynecology, pediatrics, psychiatry, internal medicine, surgery and family medicine. Consistency was validated by comparing these performance criteria from 1988 to 1992. RESULTS: When all six clerkships were assessed by year, there was no uniform trend of improved performance over time. In the obstetrics-gynecology block, however, NBME scores and FGs were highest for students assigned to the fifth and sixth rotation as compared to the first two groups (P < .02). No such trend was noted with the departmental written examination. In surgery, DE and FG were always lower in the first rotation (P = .0001). Psychiatry DE scores were significantly higher on the second or third blocks as compared to the fifth and sixth rotation positions (P < .001). Students had a higher FG in pediatrics when the sixth position was compared to the second block (P = .02), but the DE grades and NBME scores were not altered by rotational schema. In family medicine and internal medicine, no effect of rotation was noted. CONCLUSION: Third-year clerks tended to have higher NBME scores and FGs in obstetrics-gynecology if they selected this rotation later in the academic year. Surgery DEs and FGs were lowest if selected first in the academic year. There was no similar trend in other nonsurgical specialties. These data suggest that prior clinical rotations positively influence student performance in obstetrics-gynecology.

Clinical Clerkship↗
PubMed1996

Estimating birth weight in twins. Comparison of eight sonographic models.

OBJECTIVE: To establish the relative accuracy of eight sonographic models that use one to four fetal biometric measurements to derive birth weight in twin pregnancies. STUDY DESIGN: Over three years, 181 twin gestations with sonographic mensuration of biparietal diameter, head circumference, abdominal circumference (AC) and femur length (FL) within 96 hours of delivery were analyzed. Analysis of variance followed by Student-Newman-Keul's test was used to determine the relative accuracy of the eight models. A receiver-operating characteristic (ROC) curve was constructed to determine the sonographic estimate that would consistently identify a nonvertex twin B with a birth weight of < or = 1,500 g. RESULTS: The mean gestational age was 32.4 +/- 4.3 (SD) weeks, and the mean birth weights for twins A and B were 1,851 +/- 676 and 1,883 +/- 655 g, respectively. For both fetuses, the mean standardized absolute error was significantly higher for estimates based on one fetal parameter (AC or FL). Regardless of presentation (A or B, vertex or nonvertex) or whether the actual birth weight was < or = 1,500 or > 1,500 g, accuracy was similar between the six models that used two or more fetal parameters to predict the newborn's weight. ROC analysis revealed that among nonvertex twins B, an estimate of birth weight (based on BPD and AC or AC and FL) < or = 1,700 g will consistently identify the newborn with a birth weight < or = 1,500 g. CONCLUSION: Sonographic models that use two fetal parameters are adequate for assessing birth weight in twin gestations regardless of position or if the birth weight is < or = or > 1,500 g.

Adult↗
PubMed1996

The effect of levenogesterol (Norplant) contraception on coagulation as measured by antithrombin-III levels.

PURPOSE: To determine the effect of contraception given immediately postpartum on coagulation as measured by antithrombin III. STUDY DESIGN: In this prospective study, parturients (n = 85) self selected three means of postpartum contraception: levenorgesterol implants, oral contraceptives, or a barrier method. RESULTS: Baseline coagulation was assessed by antithrombin-III levels in each of the 85 women within 48 hours of delivery (100.35 +/- 1.61%) and at one (109.1 +/- 1.89%) and six (105.51 +/- 1.71%) weeks postpartum. There was a rise in antithrombin-III after delivery but there were no significant differences between the groups. CONCLUSION: The levenorgesterol implant system did not cause a decrease in antithrombin-III in normal parturients.

Antithrombin III↗
PubMed1996

Neonatal electrolyte response to amnioinfusion with lactated Ringer's solution vs. normal saline. A prospective study.

OBJECTIVE: To determine if amnioinfusion with normal saline vs. lactated Ringer's solution crystalloids causes electrolyte imbalance in the human neonate. STUDY DESIGN: Over two months, all parturients undergoing amnioinfusion in the active phase of labor were prospectively randomized to receive either normal saline (n = 37) or lactated Ringer's solution (n = 30). Maternal electrolytes were obtained prior to amnioinfusion, and neonatal electrolytes were obtained from cord blood samples at the time of delivery. RESULTS: Our results showed the two groups were similar in maternal age, ethnicity, gravidity, parity, gestational age, maternal electrolyte levels prior to amnioinfusion, amount of solution amnioinfused, duration of labor after amnioinfusion, mode of delivery and mean birth weight. The chloride concentrations were nearly identical among neonates who had received normal saline and those who had received lactated Ringer's solution (102 +/- 2.1 SD and 104 +/- 2.4 mmol/L, respectively; P = 1.0). Other electrolytes were likewise not significantly different regardless of the crystalloid infused. CONCLUSION: Unlike the fetal sheep model, amnioinfusion with normal saline is not associated with hyperchloremia in the human neonate.

Adolescent↗
PubMed1996

Combining medical and mechanical methods of cervical ripening. Does it increase the likelihood of successful induction of labor?

OBJECTIVE: To determine if combining two commonly used methods or cervical ripening (intracervical prostaglandin E2 [Pge2] gel and Foley balloon catheter) would result in a higher number of successful inductions and fewer cesarean sections when compared to PGE2 gel alone. STUDY DESIGN: Seventy-eight patients with unfavorable cervixes eligible for induction of labor were prospectively randomized to receive either one dose (0.5 mg) of PGE2 gel followed by insertion of a 24-French Foley catheter (group 1, 41 patients) or two doses of 0.5 mg of intracervical gel (group 2, 37 patients). Outcome parameters included change in Bishop score, number of failed inductions, rate of cesarean section, rate of uterine hyperstimulation and postpartum infection. RESULTS: Patients in group 1 had a significant increase in posttreatment Bishop scores (7.26 +/- 2.0 SD vs. 4.82 +/- 1.8 P = .0001) and fewer failed inductions (0 vs. 6, P = .009) when compared to patients in group 2. Abdominal delivery rates, uterine hyperstimulation and infections complications were not different between the two groups. CONCLUSION: The combination of the Foley balloon and prostaglandin gel significantly improved the Bishop score and led to fewer failed inductions, although it did not increase the vaginal delivery rate.

Adult↗
PubMed1996

Intrapartum amniotic fluid index. A poor diagnostic test for adverse perinatal outcome.

OBJECTIVE: To determine if an intrapartum amniotic fluid index (IAFI) < or = 5.0 cm, or any other level, is associated with abdominal delivery for fetal intolerance to labor or Apgar scores < 7 at one and five minutes. STUDY DESIGN: Prospectively IAFI was obtained in the latent phase of labor in 1,000 parturients at > 26 weeks. Receiver operating characteristic curves were utilized to determine if any IAFI could be utilized to predict adverse outcome among (1) the entire population, (2) complicated pregnancies, (3) uncomplicated pregnancies, (4) term, or (5) preterm gestation. RESULTS: The frequencies of abdominal delivery for suspected fetal intolerance and low Apgar scores were similar among patients with IAFI < or = 5.0 cm (n = 288) versus those with IAFI > 5.0 cm. All five receiver operating characteristic curves indicated that IAFI is a poor predictor of adverse outcomes. At all the discriminatory IAFIs (0-20 cm), the false positive rate was virtually identical to the true positive rate. CONCLUSION: IAFI appears to be a poor screening test for identifying those at risk for abdominal delivery for presumed fetal distress or for birth of an infant with low Apgar scores.

Amniotic Fluid↗
PubMed1995

The irritable uterus: a risk factor for preterm birth?

OBJECTIVE: Our aim was to determine the incidence and preterm delivery rate along with the indication for delivery in patients with uterine irritability. STUDY POPULATION: In this retrospective, descriptive study, 17,186 patients with well-defined high-risk factors were compared with 2637 women with uterine irritability. RESULTS: The incidence of preterm labor in patients with uterine irritability was 18.7%, significantly less than in those with other high-risk factors (odds ratio 0.35, 0.31 < odds ratio < 0.38). However, women with uterine irritability who experience preterm labor, compared with other high-risk factors, are much more likely to deliver before 34 weeks' gestation (odds ratio 2.50, 2.07 < odds ratio < 3.03) and more than twice as likely to deliver as a result of advanced preterm labor or membrane rupture (odds ratio 2.20, 1.75 < odds ratio < 2.78). CONCLUSIONS: The incidence of preterm labor in women with uterine irritability is not as frequent as in patients with other high-risk factors. However, preterm labor does occur in patients with uterine irritability at a rate higher than that in the general obstetric population (18.7% vs 11.0%). Because it appears that women with uterine irritability have more resistance to conventional tocolytic therapy, this condition should prompt the physician to use more aggressive perinatal assessment.

Adult↗
PubMed1995

Climatic factors and preeclampsia-related hypertensive disorders of pregnancy.

Seasonal variations of temperature and humidity are said to influence the incidence of hypertensive disorders of pregnancy. Pregnant women with hypertensive disorders of pregnancy were assessed on the basis of temperature and relative humidity at diagnosis. Temperature variations with constant high humidity do not influence the incidence of preeclampsia-eclampsia-related hypertensive disorders of pregnancy.

Eclampsia↗
PubMed1995

Massive congenital intracranial teratoma with skull rupture at delivery.

The majority of case reports concerning intracerebral tumors are almost equally divided between teratomas and gliomas. We report a case of congenital intracranial teratoma with suggested management. An 18-year-old woman at 30 weeks' gestation in active labor because of severe fetal hydrocephalus and polyhydramnios was delivered by cesarean section. Spontaneous rupture of the neonatal skull led to delivery of a stillborn infant; a congenital teratoma was found. Although intracranial teratoma is a well-recognized entity in the differential diagnosis of pediatric brain tumors, massive congenital teratoma replacing cerebral hemispheres of a fetus has been seldom reported. Antenatal diagnosis of the neoplasm and abdominal delivery may not improve outcome.

Adolescent↗
PubMed1995

Comparison of anterior colporrhaphy and retropubic urethropexy for patients with genuine stress urinary incontinence.

OBJECTIVE: Our purpose was to compared the efficacy of anterior colporrhaphy and retropubic urethropexy performed for genuine stress urinary incontinence. STUDY DESIGN: A retrospective analysis was performed on women who underwent either anterior colporrhaphy or retropubic urethropexy for genuine stress urinary incontinence. Patients were identified by a computer-assisted search, and these women were contacted by telephone. The interview was used to assess current continence status. Variables reviewed included demographic data, medications, hormonal status, current smoking history, significant medical and surgical history, and time to recurrence of incontinence. Operative procedure, prior or concomitant hysterectomy, history of previous incontinence procedures, concomitant surgery for repair of other pelvic floor defects, experience level of the primary surgeon, and duration of postoperative catheterization were also documented. RESULTS: Seventy-six women who had undergone surgery for genuine stress incontinence during a 4-year period were identified and evaluated by telephone interview. Fifty-six had undergone anterior colporrhaphy and 20 retropubic urethropexy. Both groups of patients were comparable in age, social status, race, parity, and weight. The duration of follow-up (mean +/- SD) was 66.6 +/- 14.2 months (range 48 to 96 months). Concurrent surgery to repair other pelvic floor defects was more common in patients undergoing anterior colporrhaphy than in patients undergoing retropubic urethropexy (p < 0.05). Of the 56 patients treated with anterior colporrhaphy, 26 (46%) were continent at the time of interview versus 15 of 20 (75%) treated with retropubic urethropexy (p < 0.05). Times to recurrence for anterior colporrhaphy and retropubic urethropexy were not significantly different. History of previous incontinence procedures, concomitant hysterectomy, previous hysterectomy, duration of postoperative catheterization, obesity, chronic lung disease, and smoking were not correlated with success for either procedure. Experience of the primary surgeon did have a significant effect on success, with attending staff having a better cure rate than resident surgeons (p < 0.05). CONCLUSION: Retropubic urethropexy was significantly more effective than anterior colporrhaphy for long-term cure of genuine stress urinary incontinence. We believe these conclusions should be tempered because of the complex nature of genuine stress incontinence. Patients having anterior colporrhaphy may represent a high-risk group because nearly all of them had associated pelvic floor defects. Experience of the surgeon seems to enhance the likelihood of success and may reflect subtle modifications of technique.

Female↗