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Biomedical subjects

R W Martin

Publications and source records attributed to R W Martin.

At least 145 records · Page 8Linked to original sources
PubMed1989

Experimental evaluation of an endoscopic ultrasound probe: in vitro and in vivo canine studies.

We developed an endoscopic echo probe that can be passed via the biopsy channel of a flexible fiberoptic or video endoscope with a 3.5-mm channel. The probe moves along the gastrointestinal wall under direct endoscopic vision. The translational scanning action is sensed by a position potentiometer and combines with the ultrasonic B-mode echoes to produce a cross-sectional image of the wall. The system uses an ultrasound frequency of 20 MHz to produce high-resolution images. The device was used to image canine gastrointestinal tissue in vitro and in vivo during endoscopy. Ultrasound images of the gut wall correlate with histologic structure. This probe overcomes some of the problems associated with the combined ultrasound endoscopes now in use. Use of the probe with video endoscopy allows the endoscopic and ultrasound images to be displayed side by side, simplifying coordination of application of the two techniques.

Animals↗
PubMed1989

Use of prostaglandin E2 vaginal suppositories in third-trimester fetal demise.

A retrospective analysis of eight cases of third-trimester fetal demise managed with prostaglandin E2 vaginal suppositories (PGE2) is presented. Management included laminaria insertion prior to induction and an initial lower dosage of PGE2. No cases of uterine rupture or cervicovaginal lacerations were encountered. A summary of the literature as it relates to PGE2 vaginal suppository use in third-trimester fetal demise is included.

Adolescent↗
PubMed1989

Cost effectiveness of ambulatory uterine activity monitoring.

A cost analysis is presented comparing 34 patients who received uterine activity monitoring versus 33 patients who attempted to detect uterine activity by palpation. All patients were at high risk for preterm delivery and were given the same educational information and prenatal care regarding signs and symptoms of preterm labor. The results revealed an increase in newborn days (640) and cost to those patients who were in the self-palpation group ($13,364) compared to monitored parturients (268 days and $8,633). The difference was attributed to neonatal morbidity from an increased number of preterm deliveries greater than 26 weeks but less than 37 weeks (P = 0.04). The increase in NICU days was significant (P = 0.03). No difference in normal newborn costs for infants delivered after greater than 33 weeks could be detected between the two groups, but morbidity was increased among control infants delivering between 34 and 36 weeks. Uterine activity monitoring to prevent preterm birth appears to be medically effective and reduces cost.

Cost-Benefit Analysis↗
PubMed1989

A 20-MHz ultrasound system for imaging the intestinal wall.

An ultrasound system has been developed which uses high-frequency (20 MHz) ultrasound to provide high-resolution images of tissue. The system provides 0.21-mm range and 0.65-mm lateral resolution. The transducer aperture size is 1.8 mm maximum. Miniature probes have been developed which can image via the biopsy channels of standard fiberoptic endoscopes as well as probes for imaging in vitro. A commercially available video "frame grabber" is used in conjunction with a standard microcomputer for image acquisition. This allows images to be displayed and recorded on standard television equipment and be stored and manipulated digitally. The features of the system allow in vivo imaging, in vitro imaging after resection, and histological images of the same tissue region to be acquired and compared. This method is particularly useful in learning how to correctly interpret ultrasonic images of the intestinal wall. The use of 20 MHz is advantageous in achieving excellent resolution and small size probes. The system provides a unique approach to imaging the intestinal wall.

Analog-Digital Conversion↗
PubMed1989

Measurement of left ventricular ejection fraction and volumes with three-dimensional reconstructed transesophageal ultrasound scans: comparison to radionuclide and thermal dilution measurements.

A transesophageal, ultrasonic cardiac imaging probe was built that incorporated a mechanism for changing the angle of the imaging plane of a conventional phased array in a precise and known manner. This probe was used to acquire an angular spatial sequence of two-dimensional images of the left ventricular cavity over a series of cardiac cycles by sweeping the imaging plane through it stepwise. The endocardial borders of these images were manually outlined off-line and the application of a three-dimensional reconstruction algorithm was then used to compute the left ventricular end-diastolic and end-systolic volumes and ejection fraction. A study was conducted with seven anesthesized dogs to compare ultrasonic determinations by this method with determinations and measurements made using radionuclide and thermal dilution methods. Comparison of 33 ejection fractions, measured by the ultrasonic volume method and by the gated blood pool radionuclide approach, yielded a correlation coefficient of 0.87 and a standard error of the estimate of 5.7% measured over a range of 10% to 58% (average, 40%). Comparison of the ultrasonically measured volumes with those calculated from stroke volume (derived from thermal dilution cardiac output measurement) and ejection fraction (measured by radionuclide technique) produced a correlation coefficient of 0.92 and a standard error of the estimate of 10.3 mL over a range of 18 to 130 mL (average, 56 mL). The accuracy of volume and ejection fraction measurements with this new ultrasonic method seems comparable to that of other currently used clinical approaches such as radionuclide and angiography.

Animals↗
PubMed1989

Perinatal aspects of abdominal surgery for nonobstetric disease.

Surgical interventions for nonobstetric reasons during pregnancy are reported to occur in 0.2% to 2.2% of all gestations with obvious perinatal implications. In this retrospective study, 57 parturients were identified who underwent nonobstetric abdominal surgery. Thirty-one patients underwent exploratory celiotomy for suspected appendicitis, 16 for adnexal disease other than ectopic pregnancy, six for cholecystectomy, three for intestinal disorders, and one with a pheochromocytoma. Alterations in disease expression are related to the severity of the disease and advancing gestational age, being more important in cases of appendicitis. Preterm labor reflecting fetal morbidity relates to the presence of peritonitis and then only during the third trimester. In this retrospective study, tocolysis with intravenous magnesium sulfate had an uncertain effect on the incidence of preterm delivery. Prospective studies will be required to assess the indications and limitations of tocolysis for nonobstetric abdominal surgical conditions.

Abdomen↗
PubMed1989

Utilization of hydralazine or alpha-methyldopa for the management of early puerperal hypertension.

Despite the importance of pregnancy-induced hypertension (PIH), there are few published investigations of therapeutic approaches for the postpartum management of such patients. Twenty-six gravida patients with PIH were prospectively studied during the first 24 hours after delivery while receiving intravenous magnesium sulfate. Each study subject was randomly assigned to a group also systemically administered either hydralazine or methyldopa. During the study interval, hourly measurements of blood pressure, pulse, fluid intake, and urine output were recorded. Hydralazine was found to be superior in its ability to effect more rapidly a lower mean arterial blood pressure. No significant differences in urine output or time until onset of diuresis were noted among treatment groups. No serious side effects were encountered with the use of either antihypertensive agent. Based on these preliminary findings, it appears that hydralazine is the less costly and more effective medication to lower mean arterial blood pressure in the immediate postpartum period.

Blood Pressure↗
PubMed1989

Measurement of stroke volume with three-dimensional transesophageal ultrasonic scanning: comparison with thermodilution measurement.

The accuracy of measuring cardiac stroke volume with a new transesophageal phased array ultrasonic probe was investigated in 10 dogs. The method involved scanning the heart to obtain serial images covering the entire left ventricular cavity at end-expiration. An off-line computer analysis of the images was used to form three-dimensional reconstructions of the left ventricular cavity at end-diastole and end-systole, from which stroke volume was determined. Comparison with stroke volume determined by thermodilution during a wide range of hemodynamic conditions gave the following results for least-squares regression on 57 determinations (with the 95% confidence limits in parentheses): slope 0.95 (0.842-1.06), ordinate intercept 2.1 (2.0-2.2) ml, standard error of the estimate 4.1 ml, and correlation coefficient of 0.92 (0.87-0.95). Histologic examination of sections of esophagus surrounding the tip of the probe in nine dogs demonstrated minimal trauma to the esophageal wall, with eight specimens described as normal and one showing mild inflammation. The authors conclude that three-dimensional reconstruction of the left ventricular cavity from multiple transesophageal images offers a safe and accurate, although presently tedious, method for determining stroke volume.

Animals↗
PubMed1989

Teaching third-year medical students how to care for terminally ill patients.

Most medical schools in the United States introduce students to the care of dying patients. In most cases, there is no immediate practical application of the material, and many medical students find it very difficult to interact with a terminally ill person in a clinical situation. The authors describe a successful seven-day course offered annually since 1979 to third-year medical students. The course is an integrated program for teaching the students an effective way to deal with terminal illness, using lectures, audiovisual aids, and group and individual sessions to enhance self-awareness and a practical application of the material in a clinical setting.

Education, Medical, Undergraduate↗
PubMed1989

Incarceration of the retroverted gravid uterus: report of four patients managed with uterine reduction.

Incarceration of the retroverted gravid uterus may have an adverse effect on pregnancy. To evaluate these effects, we reviewed obstetric records to identify parturients with the diagnosis of incarceration of the retroverted uterus during the years 1977 to 1987. Four such patients were identified by this retrospective review, for a calculated incidence in our primary population (patients not referred for evaluation who also received prenatal care at only one hospital) of one case per 10,384 live births. The incarceration was successfully reduced in all four patients without surgical intervention, and all had a normal infant of appropriate weight at term.

Diagnosis, Differential↗
PubMed1989

Acne fulminans.

Acne fulminans is a unique type of acne that presents acutely and dramatically with fever, weight loss and papulopustular lesions that are highly inflamed, tender and, eventually, ulcerative. These lesions occur on the face, torso and upper extremities. Musculoskeletal symptoms and hematologic manifestations frequently accompany this disorder. Acne fulminans in a 13-year-old boy was effectively treated with isotretinoin, prednisone and minocycline.

Acne Vulgaris↗
PubMed1989

Group B streptococcal sepsis and death in utero following funipuncture.

The technique of umbilical cord puncture for diagnosis and therapy, which has been shown to be feasible and relatively safe for both mother and fetus, is being used increasingly. The fetal loss rate with this technique has been estimated to be approximately 1%. A case is presented of fetal death from group B beta-streptococcal sepsis after funipuncture, the first report of this complication.

Adult↗
PubMed1989

Conservative management of Cushing's syndrome in pregnancy. A case report.

A woman with clinical and laboratory findings of Cushing's syndrome was managed during pregnancy without the use of surgery or drugs to lower her serum cortisol. A good maternal and infant outcome was achieved with conservative measures, and surgical removal of an adrenal adenoma was delayed until the postpartum period.

Adenoma↗
PubMed1989

Detection of glucose intolerance in pregnancy.

Between 6 and 28 weeks of gestation, 2-hour postprandial blood glucose determinations were performed on 66 pregnant patients who had no history of diabetes. Each patient received two methods of carbohydrate loading on separate occasions in a random, crossover fashion. One group received a 100-g carbohydrate meal and then a 50-g glucose load (Glucola). The order of the test regimens was reversed for the second group. The average 2-hour postprandial glucose value following a meal was 103.1 +/- 3.7 mg/dL, and the mean value for the 2-hour postprandial glucose following Glucola was 102.5 +/- 3.8 mg/dL. The difference in glucose values obtained with the two methods was not statistically significant. A 12% incidence of emesis was encountered after Glucola but none was encountered after the meal. The 100-g carbohydrate meal is recommended as the method of testing for glucose intolerance.

Adolescent↗
PubMed1988

Comparison of oral ritodrine and magnesium gluconate for ambulatory tocolysis.

Magnesium sulfate has been administered intravenously to arrest preterm labor but the oral form of this drug cannot be used for continual tocolysis. This trial involved the administration of oral magnesium gluconate to determine its effectiveness compared with that of ritodrine hydrochloride in 50 patients whose labor had been arrested by parenteral therapy. Group A (n = 25) received 1 gm of oral magnesium gluconate every 2 to 4 hours for tocolysis and group B (n = 25) received 10 mg of ritodrine every 2 to 4 hours. The number of patients who progressed to 37 weeks' gestation was similar (group A, 21 versus group B, 19) and the time gained in utero was not different (group A, 6.4 weeks versus group B, 5.9 weeks). There was a trend toward more side effects with the use of ritodrine (40%) compared with magnesium gluconate (16%), but the numbers were too small to reveal a significant difference. These data suggest that magnesium gluconate used as an oral tocolytic is as effective as a beta-agonist in patients whose labor is arrested initially with intravenous therapy.

Administration, Oral↗