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Biomedical subjects

R W Martin

Publications and source records attributed to R W Martin.

At least 19 recordsLinked to original sources
PubMed1995

Incidence of adverse cardiopulmonary effects with low-dose continuous terbutaline infusion.

OBJECTIVE: Our purpose was to determine the incidence of adverse cardiovascular effects of terbutaline sulfate when administered as a continuous subcutaneous infusion in women with arrested preterm labor. STUDY DESIGN: Over a 6-year period records from 8709 women prescribed this therapy for preterm labor that had previously been arrested with other intravenous tocolytics were reviewed. These women were assessed daily for cardiovascular complaints and tolerance of the medication, while either in the hospital or at the home (by telephone). The main outcomes studied were the occurrence of pulmonary edema, sustained cardiac arrhythmias, chest pain, or myocardial ischemia. Any maternal death regardless of cause was also reviewed. RESULTS: Of the 8709 subjects, 47 (0.54%) had one or more cardiopulmonary problems. Pulmonary edema developed in 28 patients (0.32%) while receiving continuous subcutaneous infusion of terbutaline, 5 at home and 23 in the hospital. Of the total, 17 women were being treated concurrently with large amounts of intravenous fluids and one to three other tocolytic agents. In the 11 remaining subjects, 4 were diagnosed with pregnancy-induced hypertension and/or multiple gestation. Nineteen patients experienced other adverse cardiovascular effects, including electrocardiogram changes, irregular heart rate, chest pain, or shortness of breath. CONCLUSIONS: Continuous terbutaline infusion for women with stabilized preterm labor is associated with much fewer adverse effects than previous literature regarding intravenous beta-adrenergic agonist therapy would suggest.

Adrenergic beta-Agonists↗
PubMed1995

Simultaneous M-mode echoesophagram and manometry in the sheep esophagus.

We report the simultaneous measurement of esophageal wall layer thickness and intraluminal pressure in the sheep esophagus using a miniature suction device incorporating a high-frequency ultrasound transducer and a manometry system. Transnasal placement of the device into the distal esophagus of a conscious sheep allowed observation of 133 swallowing events during three trials, each lasting from 45 to 60 minutes. In a fourth trial, 11 sequential dry and 23 sequential wet swallows were compared. Maximum manometric pressure, esophageal wall layer thickness, and duration of contraction were measured. All swallowing events produced simultaneous increases in intraluminal pressure and esophageal wall thickness. Mean maximal pressures were lower for dry swallows (18 +/- 2.1 mm Hg) than wet swallows (22 +/- 3.0 mm Hg) (p < .01). Thickness of the inner (circular) muscle layer increased above baseline by 124% for dry swallows and 161% for wet swallows (p < .01). We conclude that thickening of the esophageal inner (circular) muscle layer may be important in the generation of intraluminal esophageal pressure in the sheep esophagus.

Animals↗
PubMed1993

Cutaneous giant cell hyalin angiopathy.

Giant cell hyalin angiopathy (GCHA) is an unusual histologic finding associated with inflammation. The lesion has previously only been reported intraorally and is usually preceded by trauma. We report the first case of cutaneous GCHA. The eosinophilic, amorphous material (so-called "hyalin") stained for light chain products, suggesting that their deposition resulted from a reactive process associated with inflammation.

Adult↗
PubMed1992

Vaginal birth after cesarean delivery: are there useful and valid predictors of success or failure?

OBJECTIVE: Before parturition are there useful and valid predictors of successful or unsuccessful vaginal birth after previous cesarean birth that could be used to enhance the obstetric care of a patient and her pregnancy? STUDY DESIGN: The clinical course and outcome of all patients who attempted vaginal birth after cesarean delivery at one level III center during 1989 were evaluated to identify factors prognostic of a successful or unsuccessful patient group; use of this information in stepwise logistic regression and cluster analysis was disappointing. RESULTS: No single criterion or optimal clusters of factors were found and no equation achieved greater than 75% predictability of outcome with acceptable sensitivity and specificity. CONCLUSIONS: Before parturition prediction of outcome of vaginal birth after cesarean delivery is tenuous regardless of past obstetric history or recent clinical parameters. Thus it seems appropriate to encourage a trial of labor in almost all patients with a prior low-segment uterine incision (transverse or vertical) unless there is a strong physician or patient-derived contraindication to such an undertaking.

Body Weight↗
PubMed1992

Measurement of amniotic fluid volume: accuracy of ultrasonography techniques.

OBJECTIVE: Our purpose was to determine amniotic fluid volume by the dye-dilution technique and compare it with the amniotic fluid index, largest vertical pocket, and two-diameter pocket (defined as vertical x horizontal of the largest vertical pocket). STUDY DESIGN: This prospective study involved 40 women undergoing amniocentesis in late pregnancy to detect fetal lung maturity or evidence of chorioamnionitis. The amniotic fluid volume was quantified ultrasonographically by means of the amniotic fluid index, largest vertical pocket, and two-diameter pocket. During amniocentesis the fluid volume was calculated by the dye-dilution technique of Charles and Jacoby. RESULTS: Ultrasonographic measurements by amniotic fluid index, largest vertical pocket, and two-diameter pocket correctly predicted normal amniotic fluid and hydramnios (74%). A new measurement, two-diameter pocket, gave a significantly more accurate estimate of oligohydramnios than did amniotic fluid index (p < 0.002) or largest vertical pocket (p < 0.0003). CONCLUSION: All three indices are moderately accurate in identifying normal amniotic fluid volume and hydramnios. Two-diameter pocket is the most accurate test to predict oligohydramnios.

Adolescent↗
PubMed1992

Oral magnesium and the prevention of preterm labor in a high-risk group of patients.

OBJECTIVE: The null hypothesis of this study is that treatment with oral magnesium gluconate 1 gm four times daily will not decrease the rate of preterm labor and delivery in a high-risk group of pregnant women. STUDY DESIGN: Fifty-four women at risk for preterm delivery were selected randomly to receive magnesium gluconate 1 gm orally four times daily or placebo. These women were monitored prospectively for signs and symptoms of preterm labor. A subgroup of 31 women also received a home uterine activity monitor. The serum magnesium level was measured initially and again 2 weeks after study enrollment. The data were analyzed with Fisher's exact test and analysis of variance. RESULTS: Preterm labor developed in 15 women in the placebo group and in 16 women in the magnesium group. There were no differences in birth weight or gestational age at delivery. The mean increase in serum magnesium level while the patients were taking magnesium gluconate was 0.10 mg/dl (p = not significant). Five women did not have an increase in serum magnesium level and preterm labor developed in all of them. CONCLUSION: Magnesium gluconate in a dose of 1 gm four times daily is not effective for preventing preterm delivery in a high-risk group of patients.

Administration, Oral↗
PubMed1992

Adjunctive antibiotic treatment of women with preterm rupture of membranes or preterm labor.

Subclinical infection is associated with preterm rupture of the membranes (PROM) and preterm labor (PTL) in many cases. It was hypothesized that antibiotic treatment might delay delivery and/or decrease infectious morbidity in those with PROM or PTL. Patients from 19 to 34 weeks with PROM and no labor or PTL with intact membranes (but not both) were separately randomized to receive ampicillin versus placebo in addition to usual therapy. There were 36 women with PTL (21 ampicillin/15 placebo) and 84 with preterm PROM (41 ampicillin/43 placebo). Demographically, the treatment and placebo groups were similar. Outcome variables analyzed included delivery delay after treatment, maternal chorioamnionitis/endometritis, Apgar score, neonatal infection, or respiratory distress, and hospital stay. There were no significant differences between the ampicillin and placebo groups in those with PTL or preterm PROM as it concerned outcome parameters. Adjunctive ampicillin used for treatment of idiopathic PTL or preterm PROM was not beneficial in this study.

Adult↗
PubMed1992

Clinical application of linear ultrasound probes.

The linear ultrasound probe should be viewed as an adjunct to conventional endoscopic ultrasonography with combined ultrasound endoscopes. It certainly does not replace these instruments for staging neoplasms and imaging extraintestinal organs such as the pancreas. It can be a simpler alternative to these instruments when applied at the time of endoscopy to obtain more information about wall thickness and the cause of an intramural mass. It can add information when used to image within impassable malignant strictures. Further development of the linear probes with the addition of a balloon over the transducer and the advent of new probes that utilize other scanning mechanisms is anticipated and should make this imaging system even more useful.

Endoscopy↗
PubMed1992

Reduction in adherence of Actinomyces viscosus after exposure to low-frequency acoustic energy.

The ability of low-frequency (200 Hz) acoustic energy to reduce the adherence of Actinomyces viscosus T14V to saliva-treated hydroxyapatite (SHA) disks was studied. An acoustic pressure range between 0 and 65 kPa and exposure durations between 0 and 8 min were used to study the levels necessary to significantly alter adherence. The effects of acoustic exposure on both bacteria in liquid and bacteria already adhering to SHA disks were studied. A modified enzyme-linked immunosorbent assay was used to assess bacterial adherence. For bacterial suspensions exposed prior to addition to SHA disks, it was found that reductions in adherence were greater for lower bacterial concentrations. Exposure of bacteria already adhering to SHA disks resulted in a decrease in adherence that was independent of the bacterial concentration and linearly related to the logarithm of the exposure duration. In addition to affecting adherence, acoustic energy also dispersed bacterial aggregates. Our results support the concept that low-frequency sonic energy applied orally may be of therapeutic value in reducing adherence and colonization of teeth by plaque bacteria.

Acoustic Stimulation↗
PubMed1992

Trial of labor after cesarean delivery: experience in the non-university level II regional hospital setting.

OBJECTIVE: We sought to determine the extent to which vaginal birth after cesarean delivery was attempted since 1987 or 1988 in a representative sample of three regional level II hospitals in Mississippi. METHODS: The medical record department in each hospital identified all potential study subjects for this retrospective case series. One author abstracted relevant information from each medical record and entered it into a relational data base. RESULTS: Among 18,703 live births, 1574 patients had previous abdominal delivery (8.4%). Trial of labor was undertaken in 286 patients (18%), with an overall successful vaginal delivery rate of 71%. Although success rates for the three level II hospitals were similar (63-81%), utilization rates varied considerably (7-40%). One uterine dehiscence led to hysterectomy; otherwise, there were no serious perinatal complications or differences in measures of maternal morbidity, except for a higher incidence of endomyometritis with failed trial of labor (13 versus 3%). The only consistent differences observed between successful and unsuccessful trials in all groups were length of hospitalization and rate of cervical dilatation in active labor (1.4 versus 0.5 cm/hour). CONCLUSION: Although each regional level II hospital successfully conducted trials of labor in patients with previous cesarean birth, there was considerable variation among sites regarding frequency of utilization, suggesting a strong influence of nonclinical patient-physician factors upon the decision-making process.

Cesarean Section↗
PubMed1992

Ascites: a portent of cardiopulmonary complications in the preeclamptic patient with the syndrome of hemolysis, elevated liver enzymes, and low platelets.

OBJECTIVE: Maternal ascites is frequently found at cesarean delivery in patients with severe preeclampsia or eclampsia expressed as hemolysis, elevated liver enzymes, and low platelets (HELLP syndrome). We attempted to determine whether large-volume maternal ascites present at cesarean delivery in HELLP syndrome patients is correlated with disease severity or with any specific form of increased maternal morbidity. METHODS: For this retrospective case series, we reviewed the medical records of 190 patients and noted the presence or absence of large-volume maternal ascites, peripartum complications, laboratory data, and specific operative techniques. RESULTS: The incidence of large-volume ascites in patients with HELLP syndrome who underwent abdominal delivery was approximately 10% in classes 1, 2, and 3. Compared with HELLP syndrome patients without ascites, those with HELLP-associated ascites at surgery had a significant sixfold increase in the incidence of congestive heart failure and a ninefold increase in the incidence of adult respiratory distress syndrome, both of which usually became clinically apparent within 24 hours postpartum. Those HELLP syndrome patients without ascites at surgery developed congestive heart failure or adult respiratory distress syndrome infrequently, and more than 24 hours postoperatively. CONCLUSION: Cautious fluid administration and observation for cardiopulmonary deterioration are crucial in management of the critically ill, high-risk group of HELLP syndrome patients with large-volume ascites.

Adult↗
PubMed1991

Administration of heparin by subcutaneous infusion with a programmable pump.

Heparin has a short half-life (8 to 12 hours) and therefore must be administered by continuous infusion or by intermittent subcutaneous injection. Intermittent subcutaneous injection may lead to fluctuation in the levels of anticoagulation attained. In correcting this deficiency, the programmable automated subcutaneous infusion pump in conjunction with weekly home nursing visits has been used. Eight pregnant women with documented deep venous thrombosis or embolic events before pregnancy who received such therapy were studied. Eight similar subjects who received intermittent subcutaneous injection, matched for age, parity, site of deep venous thrombosis, and days on a regimen of heparin therapy, served as the control group. The mean daily dose of heparin by subcutaneous infusion pump was higher (29,445 vs 13,822 U), resulting in smoother, more therapeutic heparinization (mean partial thromboplastin time, 20.6 vs 10.4 seconds above control) when compared with the intermittent subcutaneous injection group (p less than 0.05, p less than 0.007). There were two complications (hematoma, site infection) in the intermittent subcutaneous injection group while none occurred in the subcutaneous infusion pump group. When used in concert with weekly home visits, the subcutaneous infusion pump method of administration allowed more even control of anticoagulation, appeared to result in fewer complications (although not statistically significant), and subjectively was better received by patients than the intermittent subcutaneous injection technique.

Adult↗
PubMed1991

The natural history of HELLP syndrome: patterns of disease progression and regression.

Despite much recent interest in HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count), there is little published information about the natural history of this unique form of severe preeclampsia-eclampsia. The time course and pattern of laboratory abnormalities for 158 patients with HELLP syndrome managed in a single tertiary referral center between 1980 and 1989 were studied retrospectively. Despite considerable patient variation, most gravid women with HELLP syndrome had decreasing platelet counts until 24 to 48 hours after delivery. Conversely, lactate dehydrogenase concentrations usually peaked 24 to 48 hours post partum. In all patients who recovered, a platelet count greater than 1,000,000/mm3 was spontaneously achieved by the sixth postpartum day or within 72 hours of platelet nadir. An upward trend in platelet count and a downward trend in lactate dehydrogenase concentrations should be apparent in patients without complications by the fourth postpartum day. These data provide baseline information against which the course of individual patients can be compared and the infrequent, atypical case identified for interventive therapy.

Analysis of Variance↗
PubMed1991

Left ventricular ejection fraction: single-plane and multiplanar transesophageal echocardiography versus equilibrium gated-pool scintigraphy.

The relative accuracy and precision of estimating left ventricular ejection fraction (EF) in dogs were assessed by two-dimensional transesophageal echocardiography (2D-TEE) and by three-dimensional transesophageal echocardiographic (3D-TEE) imaging and reconstruction. This assessment was accomplished by comparing each echocardiographic method to a gated equilibrium blood pool radionuclide (RN) standard. By using both correlation and regression analysis, 2D-TEE performed reasonably well in estimating RNEF (correlation coefficient [r] = 0.80, slope = 1.01, intercept = 6.37, standard error of the estimate [SEE], 8.98), but not as well as 3D-TEE (r = 0.86, slope = 0.83, intercept = 3.38, SEE, 5.74). Using Altman and Bland's methods of comparison analysis, it was found that 2D-TEE overestimated RNEF by 7% (standard deviation [SD], 8.8). This degree of overestimation was not consistent across the range of measurement. In contrast, 3D-TEE slightly underestimated RNEF by less than 3% and showed less variability (SD, 6.0). The accuracy of the 3D-TEE determinations was not dependent on the magnitude of EF. Additionally, a significantly higher proportion of the 2D-TEE measurements (0.30) compared with the 3D-TEE measurements (0.10) differed from RN values by more than 10% (P = 0.009, McNemar's test). At the clinically important low end of the EF range (RNEF less than or equal to 35%), 2D-TEE may be expected (with 95% confidence) to be within -15% to +28% EF of reference values, whereas 3D-TEE can be expected to be within -8% to +5% EF relative to RN.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗