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Biomedical subjects

H E Fox

Publications and source records attributed to H E Fox.

68 records · Page 4Linked to original sources

A comparative study of IPPB, the incentive spirometer, and blow bottles: the prevention of atelectasis following cardiac surgery.

Following cardiac operations, 145 patients were treated with either intermittent positive-pressure breathing (IPPB), blod bottles, or an incentive spirometer in an attempt to alter the incidence of atelectasis. Pulmonary complications occurred in 30% of the patients receiving IPPB, 15% of those using an incentive spirometer, and 8% of those using blow bottles. Gastrointestinal side-effects occurred in 20% of the IPPB group and were rare in other groups. The cost of IPPB is also considerably greater than either incentive spirometry or blow bottles. IPPB is not essential to prevention of atelectasis in postoperative cardiac surgical patients and may be inferior to other methods.

Cardiac Surgical Procedures↗

Fetal evaluation by real-time imaging.

The application of real-time imaging to the study of fetal morphology and function is an exciting advance. Rapid accurate study of fetal dynamics is possible with this apparently safe, noninvasive technique. Animal studies have revealed the general physiology of fetal breathing movements, which are now under extensive investigation with real-time imaging in the human. There is evidence for circadian rhythm of human fetal breathing movements as well as a relationship to maternal substrate loading. The presence of fetal breathing movements of the rapid irregular type may be a reassuring sign in the presence of other indicators of fetal compromise. Using real-time B-scan imaging, we have found long periods of apnea in pregnancies with normal perinatal outcome. As suggested in the animal studies, changes in fetal breathing patterns prior to fetal death may be more complex than originally thought. The techique of real-time B-scan imaging with precise definition of apnea, general movements, and fetal breathing will provide valuable information on which to base our evaluation of the clinical usefulness of fetal breathing movement studies in the management of pregnancy.

Animals↗

Pericardial drainage operations in the management of uremic pericardial effusion.

Because of frequent failures in nonoperative therapy, we have adopted early surgical drainage of the pericardium in the management of uremic pericardial effusion. This series presents the longest follow-up period of any group of patients with uremic pericardial effusion treated by surgical drainage. There have been no intraoperative deaths and no recurrences. The total hospital mortality rate was 8.3 per cent and the late mortality rate over a 72 month period was 25 per cent. Internal pericardiostomy drainage is a simple yet effective surgical solution to the life-threatening problem of uremic pericardial effusion.

Drainage↗

Antepartum fetal heart rate and uterine activity studies: I. Preliminary report of accelerations and the oxytocin challenge test.

A series of 344 antepartum fetal heart rate studies in 209 high-risk patients is described. The importance of evaluation of accelerations of the fetal heart rate as well as periodic decelerations associated with uterine activity is demonstrated. Our data suggest that the absence of accelerations of the fetal heart rate during the recording period may be associated with increased perinatal morbidity. Late decelerations may occur in the same recording session as accelerations of the fetal heart rate. The association of late decelerations of the fetal heart rate with no accelerations during the recording session is highly suggestive of increased perinatal morbidity. In high-risk patients, accelerations of the fetal heart rate and no late decelerations with uterine activity are a reassuring finding, with 91 per cent of patients showing no increased perinatal morbidity.

Adolescent↗

Long-term functional results of surgery for coronary artery disease in patients with poor ventricular function.

Thirty-two patients with coronary artery disease and an ejection fraction (EF) below 0.40 had coronary bypass and/or left ventricular aneurysm (LVA) resection. Twenty-four patients had a previous infarction, 12 had congestive heart failure (CHF), and left ventricular end-diastolic pressure averaged 15 mm. Hg. Nineteen patients had three-vessel involvement and there was an average of 2.4 vessels involved per patient. Bypass was accomplished on 87 per cent of vessels; 11 patients had resection of LVA; 11 had coronary endarterectomy. There were no hospital deaths, 63 per cent of the patients were improved, and 56 per cent were able to return to work or full activity. There were five late deaths (16 per cent). There was good functional improvement in 83 per cent of the survivors, followed 1 to 4 years. We believe that patients with poor ventricular function due to severe coronary artery disease should not categorically be denied surgery, and that operation can be done with a low hospital mortality rate and good functional results.

Adult↗

Respiratory movements and rapid eye movement sleep in the foetal lamb.

1. In foetal lambs from 40 days gestation (0.27 of term) onwards delivered into a warm saline bath, apparently spontaneous breathing movements were present intermittently. They became deeper and more rapid with increasing age.2. In foetal lambs (from 0.66 of term) in which observations were made for many days after chronic implantation of tracheal, carotid and amniotic catheters, rapid irregular respiratory movements were present up to 40% of the time, and brief gasps also were seen.3. The presence of these movements was unrelated to the foetal carotid blood gas values over a wide range of spontaneous variation.4. These foetal breathing movements were accompanied by comparatively small alterations of pulmonary volume recorded from a tracheal flowmeter, insufficient to clear the tracheal dead space. Occasionally a more prolonged expiration led to the outward flow of fluid.5. A description is given of sleep and wakefulness in foetal lambs from 0.78 of term.6. Rapid irregular breathing was associated with rapid eye movement sleep as seen in a warm saline bath or, in utero, as inferred from records of eye movements and electrocortical activity.7. Respiratory movements were often associated with relatively large variations in foetal heart rate, blood pressure and descending aortic blood flow.8. Rapid irregular foetal breathing was unaffected by section or blockade of the cervical vagi, but was abolished by general anaesthesia.9. It is concluded that respiratory movements are normally but intermittently present in the foetal lamb over the greater part of gestation.

Amniotic Fluid↗

Doppler ultrasound characteristics of fetal nasal flow in pregnancies complicated by diabetes mellitus.

The purpose of our study was to determine the Doppler ultrasound characteristics of fetal breathing-related nasal fluid flow velocity in pregnancies complicated by diabetes mellitus and to examine any changes in the timing parameters of fetal breath cycle relative to maternal blood glucose level. Fetal nasal fluid flow velocity was studied in 67 women at 30-41 weeks of gestation. In 37 cases, the pregnancy was uncomplicated; in 13 cases, the pregnancy was complicated by type I diabetes mellitus; and in 17 cases, the pregnancy was complicated by gestational diabetes. At the examination, subjects with diabetes mellitus were grouped by glucose control (normoglycemic and hyperglycemic) and by gestational age: 30-36 weeks and 37-41 weeks. Maternal hyperglycemia was defined as a plasma glucose value ranging from 140 to 205 mg per 100 ml. A continuous videotape record of the spectral Doppler imaging of fluid flow velocity in the nose was made during each study session. Based on a sample of 25 consecutive fetal breaths, the timing components of breath cycles were determined: time of inspiration (Ti), time of expiration (Te), breath-to-breath interval (Ttotal), and ratio of Ti and Te (Ti/Te). There was a statistically significant difference between the Ttotal (msec) at 30-36 weeks' gestation in the cases of diabetes mellitus with maternal normoglycemia (1,050 +/- 68 SEM) and uncomplicated pregnancy with maternal normal carbohydrate intolerance (1,221 +/- 52). There was a similar difference in the values of Te (552 +/- 37 and 660 +/- 29, respectively) at 30-36 weeks. In cases of maternal hyperglycemia at 30-36 weeks' gestation, the value of Te (689 +/- 84) was significantly higher than in cases of normoglycemia (552 +/- 37). At 37-41 weeks' gestation, only the fetal Ti/Te ratio in normoglycemic diabetic patients was significantly lower than in an uncomplicated pregnancy. No differences were found in the other timing parameters at this gestational age group in cases of diabetes mellitus relative to maternal blood glucose level. No relationship was found between the value of maternal blood glucose and either fetal Ttotal (r2 = 0.003), or Ti/Te ratio (r2 = 0.0001) in cases of diabetes mellitus. Expiratory phase of fetal breath cycle even in well-controlled normoglycemic diabetic women, is significantly shorter than in uncomplicated pregnancies before 37 weeks of gestation. Maternal hyperglycemia in these cases prolonged the duration of expiratory phase of fetal breath cycle and significantly decreased the Ti/Te ratio more than 15% at 30-36 weeks of gestation. It is suggested that blood glucose level is involved in the regulation of fetal respiratory center in pregnancies complicated by diabetes mellitus.

Analysis of Variance↗

Fetal bradycardia and uterine hyperactivity following subarachnoid administration of fentanyl during labor.

BACKGROUND AND OBJECTIVES: Changes in uterine tone have been postulated as the cause of fetal bradycardia following subarachnoid administration of fentanyl for labor analgesia. Such a case occurred in a 20-year-old parturient with an intrauterine pressure catheter in place. METHODS: The patient was given intravenous terbutaline, after which contractions ceased for 20-30 minutes and then resumed. RESULTS: The patient underwent successful cesarean delivery. Retrospective analysis of the data revealed a significant increase in uterine tone and contractions following fentanyl administration. CONCLUSIONS: This case supports the view that changes in uterine tone, producing a hyperdynamic contractile state and a resulting decrease in uteroplacental perfusion, may explain the fetal bradycardia following subarachnoid opioid administration. Cases that do not resolve spontaneously may respond to intravenous terbutaline.

Adult↗

Human immunodeficiency virus infection of early passage cervical epithelial cultures.

Women are infected with HIV in increasing numbers; the predominant mode of spread is through heterosexual transmission. Little is known regarding the mechanism of HIV transit through the female genital tract. We investigated whether early passage cervical epithelial cells could be directly infected with HIV-1LAI. Virus production was measured using the reverse transcriptase (RT) assay and direct assay for syncytia-forming units. In-situ hybridization was performed on infected cervical cell cultures. Immunostaining was carried out using a monoclonal antibody to leukocyte common antigen (LCA). Virus was recovered in the supernatants of all infected cervical cultures. Localization of HIV infection using in-situ hybridization identified rare cells in the population which gave a strong signal. These infected cells had a lymphoid morphology and were also detected using immunostaining for LAC. Cervical epithelial cells were uninfected in this in vitro model; cells in this population which supported viral replication were most likely of the macrophage/monocyte lineage.

Cells, Cultured↗

Misdiagnosed HIV infection in pregnant women: implications for clinical care.

Out of nearly 900 women in a research study of human immunodeficiency virus infection in pregnancy, 8 were subsequently found not to be infected. Misdiagnoses could have resulted from (a) laboratory errors or specimen mixups; (b) failure to follow the testing algorithm recommended by the Centers for Disease Control and Prevention to confirm results; (c) women perceiving they were infected by high-risk behavior in the absence of testing, despite the receipt of negative test results, or based on screening results only; or (d) factitious disorder, HIV Munchausen syndrome, or malingering. Because of the potentially devastating impact of an HIV diagnosis and the toxicity of HIV therapies, health care providers should obtain independent confirmation of the diagnosis before initiating treatment or followup for HIV based on patient report or provider referral. Quality test interpretation and counseling must be ensured. Therapeutic interventions may be indicated for persons intentionally and falsely presenting themselves as HIV-infected.

Adult↗