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Biomedical subjects

R W Martin

Publications and source records attributed to R W Martin.

At least 55 records · Page 3Linked to original sources
PubMed1998

Maternal mortality associated with adult respiratory distress syndrome.

BACKGROUND: Pregnancy-related adult respiratory distress syndrome (ARDS) can lead to maternal mortality and morbidity. METHODS: Records of all pregnant patients diagnosed with ARDS over a 14-year period were reviewed and the cases were stratified into survivors and nonsurvivors. RESULTS: Forty-one cases were identified and 31 survived (maternal mortality rate of 24.4%). Adult respiratory distress syndrome was diagnosed in the antepartum period in 23 (56.1%) of the patients and the majority of these cases occurred in the third trimester (73.9%). There was no statistically significant difference in demographic characteristics, preexisting diseases, or probable precipitating cause for the development of ARDS between the two groups. The cause of death among the nonsurvivors included multisystem organ failure, sepsis, cardiac arrest, and disseminated intravascular coagulopathy. CONCLUSION: Pregnancy-related ARDS continues to be associated with a high maternal mortality rate (25%). Unfortunately, the etiology for ARDS during pregnancy is not predictive of maternal outcome.

Adolescent↗
PubMed1998

System for quantitative three-dimensional echocardiography of the left ventricle based on a magnetic-field position and orientation sensing system.

Accurate measurement of left-ventricular (LV) volume and function are important to monitor disease progression and assess prognosis in patients with heart disease. Existing methods of three-dimensional (3-D) imaging of the heart using ultrasound have shown the potential of this modality, but each suffers from inherent restrictions which limit its applicability to the full range of clinical situations. We have developed a technique for image acquisition using a magnetic-field system to track the 3-D echocardiographic imaging planes and 3-D image analysis software including the piecewise smooth subdivision method for surface reconstruction. The technique offers several advantages over existing methods of 3-D echocardiography. The results of validation using in vitro LV's show that the technique allows accurate measurement of LV volume and anatomically accurate 3-D reconstruction of LV shape and is, therefore, suitable for analysis of regional as well as global function.

Algorithms↗
PubMed1998

Current distribution of sarcoptic mange in wombats.

OBJECTIVE: To determine the distribution and prevalence of sarcoptic mange in wombats, particularly the common wombat (Vombatus ursinus). DESIGN: Questionnaire survey in two parts. PROCEDURE: Questionnaires were distributed to biologists, rangers, animal carers and naturalists. Part 1 of the questionnaire aimed to determine the present distribution of sarcoptic mange in wombats (103 responses). Part 2 invited respondents to assess the prevalence of sarcoptic mange in wombats over a 3 month period (four responses). Information on wombats from 66 localities was received. Each locality represented an area of about 2500 km2. RESULTS: Mange was observed at 93% of localities surveyed and Sarcoptes scabiei was present in common wombats at 52% of localities. Sarcoptic mange was highly prevalent (22%) in two common wombat populations in Victoria. Anecdotal evidence suggested that mange epizootics are sporadic, cause significant morbidity and mortality and have a substantial effect on local abundance. The respondents did not report sarcoptic mange in either northern hairy-nosed wombats (Lasiorhinus krefftii) or southern hairy-nosed wombats (Lasiorhinus latifrons). CONCLUSIONS: Sarcoptic mange occurs in common wombat populations throughout the range of the common wombat including Tasmania and Flinders Island. While mange epizootics are sporadic, they have the potential to threaten the long-term survival of small, remnant populations.

Alopecia↗
PubMed1998

Oral magnesium for tocolysis: a comparison of magnesium gluconate and enteric-coated magnesium chloride.

PURPOSE: Following parenteral magnesium tocolysis for patients in preterm labor. The choice of oral tocolytic medications is controversial. METHODS: Over a six-month period, 47 patients who were inpreterm labor were randomized after parenteral magnesium tocolysis to receive magnesium gluconate ([Mg-g] 648 mg elemental magnesium/day) or magnesium chloride ([Mg-c] 640 mg elemental magnesium/ day). A serum magnesium was obtained 24 hours after the initiation of oral therapy. RESULTS: In the 25 patients were treated with Mg-g and 22 with Mg-c there were no differences in patient demographics, initial cervical dilatation hours on parenteral magnesium sulfate, recurrent contractions, or side effects between the two groups. The cost was also similar (Mg-c, $1.40/d; Mg-g, $2.11/d). The serum magnesium levels were higher in the Mg-c group (1.80 +/- 0.28 mg/dl) compared to the Mg-g group (1.63 +/- 0.30 mg/dl) but the difference was not significant. CONCLUSION: These two preparations of magnesium are similar in their effects on uterine activity and serum levels when used at these dosages.

Administration, Oral↗
PubMed1997

Nulliparous active labor, epidural analgesia, and cesarean delivery for dystocia.

OBJECTIVE: Our purpose was to examine the effect of epidural analgesia on dystocia-related cesarean delivery in actively laboring nulliparous women. STUDY DESIGN: Active labor was confirmed in nulliparous women by uterine contractions, cervical dilatation of 4 cm, effacement of 80%, and fetopelvic engagement. Patients were randomized to one of two groups: epidural analgesia or narcotics. A strict protocol for labor management was in place. Patients recorded the level of pain at randomization and at hourly intervals on a visual analog scale. Elective outlet operative vaginal delivery was permitted. RESULTS: One hundred women were randomized. No difference in the rate of cesarean delivery for dystocia was noted between the groups (epidural 8%, narcotic 6%; p = 0.71). No significant differences were noted in the lengths of the first (p = 0.54) or second (p = 0.55) stages of labor or in any other time variable. Women with epidural analgesia underwent operative vaginal delivery more frequently (p = 0.004). Pain scores were equivalent at randomization, but large differences existed at each hour thereafter. The number of patients randomized did not achieve prestudy estimates. A planned interim analysis of the results demonstrated that we were unlikely to find a statistically significant difference in cesarean delivery rates in a trial of reasonable duration. CONCLUSIONS: With strict criteria for the diagnosis of labor and with use of a rigid protocol for labor management, there was no increase in dystocia-related cesarean delivery with epidural analgesia.

Adult↗
PubMed1997

Are obstetric interventions such as cervical ripening, induction of labor, amnioinfusion, or amniotomy associated with umbilical cord prolapse?

OBJECTIVE: Our purpose was to determine whether intrapartum obstetric interventions are associated with umbilical cord prolapse. STUDY DESIGN: A computer search identified patients who had intrapartum umbilical cord prolapse. Thirty-seven cases were identified between 1990 and 1994 (incidence of 1.85 per 1000). These women were randomly matched to control patients with intact membranes. RESULTS: Patients with umbilical cord prolapse were delivered earlier (34.8 vs 37.1 weeks, p = 0.05). Otherwise, there were no differences between groups regarding the use of cervical ripening, incidence of labor induction, or the use of amnioinfusion and amniotomy. Although cervical dilatation and station were similar between groups at the time of admission, women with umbilical cord prolapse did not have as much descent of the presenting part associated with cervical dilatation and progressive labor compared with control patients. CONCLUSION: By themselves, obstetric interventions of cervical ripening, labor induction, amnioinfusion, and amniotomy do not increase the likelihood that a patient will have umbilical cord prolapse.

Adolescent↗
PubMed1997

Performance of a miniature magnetic position sensor for three-dimensional ultrasound imaging.

A miniature magnetic position sensor used for three-dimensional ultrasound imaging was tested for precision and accuracy in vitro. The sensor alone was able to locate points with root-mean-square (rms) uncertainty of 1.7 mm and accuracy of 0.05 +/- 0.62 mm over its specified operating range of 50 cm. With an ultrasound imaging system, a point was located from arbitrary viewing windows with 2.4-mm rms uncertainty and 0.06 +/- 0.68 mm accuracy. If viewing windows were limited to those representative of a typical ultrasound examination, the system could achieve rms uncertainty in point location of < 1 mm. Performance was not affected by operation of the imaging system when the sensor was mounted on an ultrasound scanhead. Sensitivity to metals in the operating environment was also measured.

Calibration↗
PubMed1997

Quantitative three-dimensional echocardiography by rapid imaging from multiple transthoracic windows: in vitro validation and initial in vivo studies.

Three-dimensional echocardiography has demonstrated superiority over two-dimensional techniques in the determination of left ventricular mass and volumes. We describe a technique based on a magnetic tracking system which provides rapid three-dimensional image acquisition from multiple acoustic windows. Interactive three-dimensional border tracking and reconstruction with a piecewise smooth subdivision model accurately reproduced phantom volume (calculated volume = 1.00 true volume - 0.6 ml, r = 1.000, standard error of the estimate = 1.3 ml), in vitro heart volume (calculated volume = 1.02 true volume - 1.3 ml, r = 1.000, standard error of the estimate = 0.4 ml), in vitro heart mass (calculated mass = 0.98 true mass + 1.4 gm, r = 0.998, standard error of the estimate = 2.5 gm), and in vivo stroke volume (calculated stroke volume = 1.18 Doppler stroke volume - 17.9 ml, r = 0.990, standard error of the estimate = 2.8 ml). The three-dimensional in vivo data sets, which include views from three acoustic windows, were acquired in less than 90 seconds. We conclude that this method of three-dimensional echocardiographic data acquisition and analysis overcomes limitations inherent in currently available systems.

Animals↗
PubMed1997

Psychopathologic risk factors for intentional and nonintentional injury.

OBJECTIVE: Trauma has a high rate of recurrence, suggesting that some people are more injury-prone than others. This study was performed to evaluate some of the psychological and social factors that might influence the likelihood of traumatic injury. METHODS: A case-control study was conducted to evaluate the relationship between selected psychosocial factors and traumatic injury. At a Level I trauma center, victims of intentional trauma (excluding attempted suicide), victims of nonintentional trauma, and patients undergoing elective surgery were interviewed by a person blinded to the purposes of the study. They were given an intelligence test and underwent a structured interview, yielding psychiatric diagnostic categories established in the third edition of the Diagnostic and Statistical Manual of Mental Disorders, Revised (DSM-III-R). RESULTS: Trauma patients were younger than elective surgery patients (p < 0.01) and were more likely to be men (p < 0.01). Victims of intentional injury had a higher probability of alcohol use (p < 0.01) and admitted illicit drug use (p < 0.001) than either nonintentional injury victims or elective surgery patients. Victims of intentional injury were more likely to be unemployed than those in the other two groups (p < 0.02), whereas elective surgery patients were more likely to be retired (p < 0.05) or to be disabled (p < 0.0001). The average intelligence score was slightly above the median in the nonintentional trauma group and in the control group (55th percentile and 54th percentile, respectively), compared with a mean intelligence score equivalent to the 35th percentile in the victims of intentional trauma (p < 0.001). Thirty percent of elective surgery patients met diagnostic criteria for at least one category of psychopathology, compared with 50% of nonintentional trauma patients, and 63% of intentional trauma patients (p < 0.01, trauma vs. elective surgery). Logistic regression analysis identified six variables that were independently associated with an increased tendency to be a victim of trauma: younger age, lower intelligence, antisocial personality, mental retardation, depression, and low income. CONCLUSIONS: Victims of trauma, both nonintentional, and especially intentional, have a high incidence of psychopathology. Victims of intentional trauma have significantly lower intelligence scores than either nonintentional injury or elective surgery patients. The high incidence of unemployment, alcohol abuse, and illicit drug use in victims of intentional injury might provide several opportunities for trauma prevention programs. Underlying psychological disorders will have to be addressed to reduce the likelihood of becoming a victim of trauma.

Accident Proneness↗
PubMed1997

Premature rupture of membranes at term with an unfavorable cervix: comparison of expectant management, vaginal prostaglandin, and oxytocin induction.

BACKGROUND: Our objective was to determine the best treatment for parturients at term with an unfavorable cervix and premature rupture of membranes (PROM). METHODS: In this prospective study, 96 women with PROM and an unfavorable cervix were randomized into one of three treatment groups: oxytocin induction, vaginal prostaglandin E2 gel followed by oxytocin, or expectant management. RESULTS: Length of labor, cesarean section rate, and maternal/neonatal morbidity were not significantly different. In contrast, the interval from PROM until delivery and length of hospital stay were significantly longer in the expectantly managed group than in the other groups. Four of the patients who received expectant management required delivery because of nonreassuring fetal assessments. CONCLUSIONS: Expectant management of PROM at term significantly prolongs hospital stay without decreasing the incidence of abdominal delivery or infectious morbidity. There appears to be potential for cord compression in patients managed expectantly without continuous electronic fetal surveillance.

Cesarean Section↗
PubMed1997

Twins and preterm labor.

OBJECTIVE: To assess the effect of home uterine contraction assessment (HUCA) in twin pregnancies with preterm labor (PTL) at < 24 weeks' gestation. STUDY DESIGN: In this retrospective, analytic study, patients were stratified by whether HUCA had been prescribed before or after diagnosis of PTL. The main outcomes studied were time of PTL diagnosis and delivery as well as birth weight and need for neonatal intensive care unit (NICU) admission. In 63 patients, 32 were prescribed HUCA after PTL had been arrested at < 24 weeks (group I). Thirty-one women had HUCA prescribed at 20 weeks' gestational age and then developed PTL at < 24 weeks (group II). RESULTS: Labor was diagnosed at similar times in both groups (22.8 vs 23.4 weeks), but delivery was earlier in group I (27.6 weeks vs. 34.7 weeks) than in group II. The birth weight in group I was less (918 +/- 255 g), and of the 64 infants, 55 required NICU admission as compared to 2,340 +/- 525 g and 11 of 62 infants (P < .0001, .0001) in group II, respectively. CONCLUSION: Women with twin gestations and the diagnosis of PTL prior to 24 weeks deliver later in gestation, and their infants weigh more and have fewer NICU admissions if intensive prenatal surveillance is prescribed prior to the onset of labor.

Adult↗
PubMed1996

[High frequency ultrasonography of the gastrointestinal wall].

If an ultrasound probe comes close to the area of interest, high ultrasound frequencies can be applied. Endoscopic ultrasonography is performed by means of echoendoscopes or miniature probes using ultrasound frequencies between 7 and 30 MHz. A high frequency ultrasound image of the normal gastrointestinal wall usually shows five layers corresponding closely to the histological layers of the wall. Corrections have to be made, however, for interface echoes between layers with different acoustic impedances. We describe studies performed with the aim of correlating ultrasound images of the normal and diseased gastrointestinal wall with the histology. Ultrasound images of the normal gastrointestinal wall and pathological changes like ischemia, ulcers, tumours and inflammation are presented.

Gastric Mucosa↗
PubMed1996

Postpartum tubal ligation after pregnancy complicated by preeclampsia or gestational hypertension.

OBJECTIVE: To determine the anesthetic and surgical morbidity associated with postpartum tubal ligation after pregnancy complicated by pregnancy-induced hypertension. METHODS: Preoperative hemodynamic measurements, laboratory results, choice of anesthetic technique, intraoperative hemodynamic changes, and postoperative morbidity were compared in 53 women with pregnancy-induced hypertension (hypertensive group) and 53 controls who underwent postpartum tubal ligation between October 1992 and November 1995. We used a retrospective case-control design. RESULTS: Preoperative mean blood pressure (BP) measurements ( +/- standard deviation) were greater in hypertensive women than in controls (158 +/- 22/91 +/- 12 versus 126 +/- 13/71 +/- 10 mmHg; P < .001). Among women given spinal anesthetics for tubal ligation, the minimum intraoperative systolic BP was significantly lower in controls than in hypertensive women (P < .05). However, the maximum percentage decrease in systolic BP was greater in hypertensive women than in controls (33 +/- 14 versus 22 +/- 10%; P < .05). Only one patient in each group developed intraoperative hypertension. The percentage of patients discharged later than the first postoperative day was greater in hypertensive women than in controls (23 versus 8%; P < .05). CONCLUSION: The lack of profound hemodynamic responses during spinal or general anesthesia for postpartum tubal ligation supports the continued use of this procedure in selected women with pregnancy-induced hypertension.

Female↗
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

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↗