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Biomedical subjects

C G Elliott

Publications and source records attributed to C G Elliott.

At least 37 records · Page 2Linked to original sources
PubMed1993

Predicting the presence of pulmonary function impairment in adult respiratory distress syndrome survivors.

Varying degrees of impairment in pulmonary function in survivors of adult respiratory distress syndrome (ARDS) have been reported. Physiologic indices of the severity of disease have been associated with impaired pulmonary function after ARDS, including duration of exposure to FIO2 > 0.6, AaDO2, maximal mean pulmonary artery pressure, lowest total static thoracic compliance, and peak airway pressure. Prediction of impairment following ARDS is difficult because clinical observations may reflect reversible lung injury (e.g. lung edema) and clinical features of ARDS do not predict subsequent function reliably. We developed a severity score to predict the presence of impairment of pulmonary function in 51 ARDS survivors, by examining the following clinical variables: (1) predisposing factor for ARDS; (2) age; (3) sex; (4) severity of hypoxemia; (5) smoking history; (6) number of days of positive pressure ventilation; (7) lowest total static thoracic compliance; (8) maximal mean pulmonary artery pressure, and (9) presence of barotrauma. Pulmonary function studies were performed at least 1 year after ARDS onset. The ARDSscore developed required only two variables: ARDSscorce = duration of positive pressure ventilation (days) minus lowest static thoracic compliance (ml/cm H2O). Significant correlations (p < 0.001) were found between linear regressions of percent predicted FEV1, FVC, TLC and DLCO against ARDSscore. ARDSscore > +20 predicted an 82% probability of impaired FEV1, FVC or TLC and a 100% probability of an impaired DLCO. We conclude that a score based upon duration of positive pressure ventilation and lowest static thoracic compliance predicts impaired pulmonary function more than 1 year after ARDS.

Adult↗
PubMed1993

Duplex ultrasonography for the detection of deep vein thrombi after total hip or knee arthroplasty.

The usefulness of real-time duplex ultrasonography (DU) as a screening test for deep vein thrombosis (DVT) in high-risk patients remains uncertain. To determine the sensitivity and specificity of DU for the detection of DVT, the authors prospectively studied 178 consecutive patients after total hip (n = 113) or total knee (n = 66) arthroplasty. The deep veins from the inguinal ligament to the ankle were examined first by continuous wave and then by pulsed Doppler signals as needed with real-time gray-scale ultrasound imaging using the criteria of vein noncompressibility to define DVT. Ascending contrast venography was performed within twelve hours after DU studies. Venograms and DU were interpreted independently. DU was attempted on 177 lower extremities (2 patients refused) but was judged adequate for interpretation for only 145 (82%). Venography could not be performed for 28 lower extremities and was technically inadequate for 8 studies. The primary analysis included 119 examinations for which adequate DU and ascending venograms were interpreted. DU was positive in 17 of 27 lower extremities with DVT (23 calf, 4 proximal) diagnosed by venography (sensitivity = .63; 95% confidence interval [CI] = .42 to .81), and DU was negative in 85 of 92 lower extremities with normal venograms (specificity = .92; 95% CI = .85 to .97). A secondary analysis of 81 prospectively collected anatomically complete DU studies demonstrated a sensitivity of .80 (95% CI = .56 to .94) and a specificity of .90 (95% CI = .80 to .96).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Quality assurance for respiratory care services: a computer-assisted program.

At present, the principal advantage of computer-assisted quality assurance is the acquisition of quality assurance date without resource-consuming chart reviews. A surveillance program like the medical director's alert may reduce morbidity and mortality. Previous research suggests that inadequate oxygen therapy or failures in airway management are important causes of preventable deaths in hospitals. Furthermore, preventable deaths tend to occur among patients who have lower severity-of-illness scores and who are not in ICUs. Thus, surveillance of the entire hospital, as performed by the HIS medical director's alert, may significantly impact hospital mortality related to respiratory care. Future research should critically examine the potential of such computerized systems to favorably change the morbidity and mortality of hospitalized patients. The departments of respiratory care and medical informatics at LDS Hospital have developed a computer-assisted approach to quality assurance monitoring of respiratory care services. This system provides frequent and consistent samples of a variety of respiratory care data. The immediate needs of patients are addressed through a daily surveillance system (medical director's alert). The departmental quality assurance program utilizes a separate program that monitors clinical indicators of staff performance in terms of stated departmental policies and procedures (rate-based clinical indicators). The availability of an integrated patient database allows these functions to be performed without labor-intensive chart audits.

Hospital Bed Capacity, 500 and over↗
PubMed1993

Carcinoid syndrome.

Carcinoid tumors stimulate the release of specific hormones that lead to flushing, diarrhea, and bronchospasm. Serotonin is the most significant of these substances. Recently, a somatostatin analogue as well as the longer acting octreotide have been used to inhibit tumor secretions and reduce their untoward actions. This is a case report in which somatostatin was used perioperatively for removal of carcinoid tumors with an uneventful course.

Carcinoid Tumor↗
PubMed1993

Drug-induced methemoglobinemia in a healthy 20-year-old soldier undergoing shoulder surgery.

A young adult male, ASA status I, presented for left shoulder arthroscopy. His medications included indocin for shoulder pain and chloroquine, an antimalarial. He was anesthetized using propofol, midazolam, fentanyl, and a relaxant. His initial oximetry reading of 94% saturation was erroneously attributed to shivering and to the fact that the oximeter clip was distal to the blood pressure cuff on the right upper extremity, necessitated by proximity of surgery. The initial saturation level of 94% was persistent throughout the case. The methemoglobin level drawn immediately postoperatively was 9%. The patient was treated with methylene blue which resulted in an improvement in oxygen saturation to 98%. His remaining postoperative course was uneventful, and he was released one day later.

Adult↗
PubMed1992

Low accuracy of color Doppler ultrasound in the detection of proximal leg vein thrombosis in asymptomatic high-risk patients. The RD Heparin Arthroplasty Group.

OBJECTIVE: To evaluate the ability of color Doppler ultrasound to detect proximal deep venous thrombosis (DVT) in asymptomatic high-risk patients who subsequently underwent contrast venography. DESIGN: Prospective cohort study using blinded observers, with contrast venography as the comparison standard. SETTING: Seven medical centers (university and community hospitals) participating in a clinical trial of low-molecular-weight heparin for prevention of DVT. PATIENTS: A total of 385 consecutive patients undergoing elective unilateral hip or knee replacement. MEASUREMENTS: Ten days after surgery or before hospital discharge (whichever occurred first), patients had bilateral color Doppler ultrasound examinations of the proximal veins of the lower extremities. Subsequently, a contrast venogram of the operated leg was obtained. RESULTS: Color Doppler ultrasound studies and venograms were both evaluable in 319 of the 385 patients. Deep venous thrombosis was identified by contrast venography in 80 patients (prevalence, 25%; 95% CI, 20% to 30%) and involved the proximal veins in 21 patients (prevalence, 7%; CI, 4% to 10%). For proximal DVT, color Doppler ultrasound showed poor sensitivity (38%; CI, 18% to 62%), moderately good specificity (92%; CI, 89% to 95%), and a poor positive predictive value for this population (26%). CONCLUSION: Color Doppler ultrasound examinations are insensitive to proximal DVT in asymptomatic high-risk patients and should not be substituted for venography for identifying proximal DVT in such patients.

Adolescent↗
PubMed1992

Subcutaneous low-molecular-weight heparin compared with continuous intravenous heparin in the treatment of proximal-vein thrombosis.

BACKGROUND: Low-molecular-weight heparin has a high bioavailability and a prolonged half-life in comparison with conventional unfractionated heparin. Limited data are available for low-molecular-weight heparin as compared with unfractionated heparin for the treatment of deep-vein thrombosis. METHODS: In a multicenter, double-blind clinical trial, we compared fixed-dose subcutaneous low-molecular-weight heparin given once daily with adjusted-dose intravenous heparin given by continuous infusion for the initial treatment of patients with proximal-vein thrombosis, using objective documentation of clinical outcomes. RESULTS: Six of 213 patients who received low-molecular-weight heparin (2.8 percent) and 15 of 219 patients who received intravenous heparin (6.9 percent) had new episodes of venous thromboembolism (P = 0.07; 95 percent confidence interval for the difference, 0.02 percent to 8.1 percent). Major bleeding associated with initial therapy occurred in 1 patient receiving low-molecular-weight heparin (0.5 percent) and in 11 patients receiving intravenous heparin (5.0 percent), a reduction in risk of 91 percent (P = 0.006). This apparent protection against major bleeding was lost during long-term therapy. Minor hemorrhagic complications were infrequent. Ten patients receiving low-molecular-weight heparin (4.7 percent) died, as compared with 21 patients receiving intravenous heparin (9.6 percent), a risk reduction of 51 percent (P = 0.049). CONCLUSIONS: Low-molecular-weight heparin is at least as effective and as safe as classic intravenous heparin therapy under the conditions of this study and more convenient to administer. The simplified therapy provided by low-molecular-weight heparin may allow patients with uncomplicated proximal deep-vein thrombosis to be cared for in an outpatient setting.

Double-Blind Method↗
PubMed1992

Recombinant tissue-type plasminogen activator versus a novel dosing regimen of urokinase in acute pulmonary embolism: a randomized controlled multicenter trial.

Thrombolysis of acute pulmonary embolism can be accomplished more rapidly and safely with 100 mg of recombinant human tissue-type plasminogen activator (rt-PA) (Activase) than with a conventional dose of urokinase (Abbokinase) given as a 4,400-U/kg bolus dose, followed by 4,400 U/kg per h for 24 h. To determine the effects of a more concentrated urokinase dose administered over a shorter time course, this trial enrolled 90 patients with baseline perfusion lung scans and angiographically documented pulmonary embolism. They were randomized to receive either 100 mg/2 h of rt-PA or a novel dosing regimen of urokinase: 3 million U/2 h with the initial 1 million U given as a bolus injection over 10 min. Both drugs were delivered through a peripheral vein. To assess efficacy after initiation of therapy, repeat pulmonary angiograms at 2 h were performed in 87 patients and then graded in a blinded manner by a panel of six investigators. Of the 42 patients allocated to rt-PA therapy, 79% showed angiographic improvement at 2 h, compared with 67% of the 45 patients randomized to urokinase therapy (95% confidence interval for the difference in these proportions [rt-PA minus urokinase] is -6.6% to 30.4%; p = 0.11). The mean change in perfusion lung scans between baseline and 24 h was similar for both treatments. Three patients (two treated with rt-PA and one with urokinase) had an intracranial hemorrhage, which was fatal in one. The results indicate that a 2-h regimen of rt-PA and a new dosing regimen of urokinase exhibit similar efficacy and safety for treatment of acute pulmonary embolism.

Acute Disease↗
PubMed1992

The adult respiratory distress syndrome. A report of survival and modifying factors.

The adult respiratory distress syndrome (ARDS) is a form of acute lung injury characterized by arterial hypoxemia, reduced thoracic compliance, normal pulmonary capillary wedge pressure, and diffuse infiltrates on chest roentgenograms. Mortality remains high and has been associated with sepsis, organ failure, age, and predisposing factors. We prospectively identified 215 ARDS patients over 34 months to examine how these factors influence outcome. One hundred two (47 percent) of 215 patients survived. Age 65 years or older was associated with a survival of 34 percent, which was statistically different from the 53 percent survival of those patients younger than 65 years (p = 0.02). Aspiration pneumonia as a predisposing factor of ARDS was associated with a better survival (p = 0.04). Survivors had statistically less organ failure and sepsis than did nonsurvivors (p less than 0.05). Cause of death was determined using the criteria of Montgomery et al for irreversible organ dysfunction. Forty-five (40 percent) of our patients died of respiratory failure (not sepsis). We conclude the following: (1) survival in our ARDS patients is different from previous reports; (2) the cause of death in our ARDS patients is different from that reported by Montgomery et al in 1985; and (3) multisystem organ failure, sepsis, age, and some predisposing factors of ARDS continue to be associated with decreased survival of ARDS patients.

Age Factors↗
PubMed1992

Pulmonary physiology during pulmonary embolism.

Acute pulmonary thromboembolism produces a number of pathophysiologic derangements of pulmonary function. Foremost among these alterations is increased pulmonary vascular resistance. For patients without preexistent cardiopulmonary disease, increased pulmonary vascular resistance is directly related to the degree of vascular obstruction demonstrated on the pulmonary arteriogram. Vasoconstriction, either reflexly or biochemically mediated, may contribute to increased pulmonary vascular resistance. Acute pulmonary thromboembolism also disturbs matching of ventilation and blood flow. Consequently, some lung units are overventilated relative to perfusion (increased dead space), while other lung units are underventilated relative to perfusion (venous admixture). True right-to-left shunting of mixed venous blood can occur through the lungs (intrapulmonary shunt) or across the atrial septum (intracardiac shunt). In addition, abnormalities of pulmonary gas exchange (carbon monoxide transfer), pulmonary compliance and airway resistance, and ventilatory control may accompany pulmonary embolism. Thrombolytic therapy can reverse the hemodynamic derangements of acute pulmonary thromboembolism more rapidly than anticoagulant therapy. Limited data suggest a sustained benefit of thrombolytic treatment on the pathophysiologic alterations of pulmonary vascular resistance and pulmonary gas exchange produced by acute pulmonary emboli.

Humans↗
PubMed1991

Computer-assisted quality assurance: development and performance of a respiratory care program.

The Departments of Respiratory Care and Medical Informatics at LDS Hospital, Salt Lake City, developed a computer-assisted system (HELP) to monitor the quality assurance (QA) of respiratory care services. The system addresses the immediate needs of patients through a daily medical director's alert report, which allows the medical director to intervene in acute situations as they arise. The department's QA program monitors and evaluates clinical indicators of staff performance in terms of stated policies and procedures. The integrated data base allows functions to be performed without labor-intensive chart reviews.

Hospital Bed Capacity, 500 and over↗
PubMed1991

Increased survival of ARDS patients with severe hypoxemia (ECMO criteria).

The adult respiratory distress syndrome (ARDS) is a form of diffuse lung injury associated with multiple risk factors. Patients with severe hypoxemia who meet blood gas criteria defined by the extracorporeal membrane oxygenation trial (ECMO) of 1974 to 1977 have a reported survival of 11 percent. The reported survival has remained unchanged for 15 years despite numerous technologic advances. We prospectively studied ARDS patients who met ECMO blood gas criteria. One hundred seventy-eight ARDS patients were prospectively screened over a 30-month period. Fifty-one of these patients met ECMO blood gas criteria and 23 (45 percent) survived (p less than 0.001 vs ECMO trial). No obvious differences in etiology, APACHE II score, organ system failure, or the incidence of sepsis was found between survivors and nonsurvivors. We conclude that survival of ARDS patients who met ECMO blood gas criteria in our institution is higher than that previously reported from both other centers and our own hospital.

Adult↗
PubMed1991

Open lung biopsy does not correlate with pulmonary function after the adult respiratory distress syndrome.

Abnormalities of pulmonary function occur following the adult respiratory distress syndrome (ARDS). To determine if open lung biopsy (OLB) during ARDS predicts late pulmonary function abnormalities, we examined nine survivors of ARDS who had OLB during ARDS. Open lung biopsy was performed within two weeks of the diagnosis of ARDS, and the following were scored by a pulmonary pathologist as to extent and severity: hyaline membranes (HM), interstitial fibrosis (IF), air space organization (AO), interstitial cellularity (IC), and type 2 cell proliferation (T2C). Pulmonary function tests performed at least one year after ARDS were also used for analysis. Percent predicted Dco, TLC, DL/VA, and FVC were regressed against extent, severity, and combined scores. No significant correlation was found despite impressive histologic abnormalities. These data suggest that the severity and extent of HM, IF, AO, T2C, or IC do not correlate with lung function following ARDS.

Female↗
PubMed1990

Hamman-Rich syndrome revisited.

In this article, we retrospectively review 29 cases of Hamman-Rich syndrome. As in some other recent reports, we have used the term "acute interstitial pneumonia" to emphasize the clinical and pathologic features of these cases and to distinguish them from the more common chronic interstitial pneumonias, particularly idiopathic pulmonary fibrosis. Of the 29 patients, 12 survived, some after a long and complicated hospitalization. The histologic features were those of organizing diffuse alveolar damage, and some patients, including survivors, had extensive fibroblastic distortion of lung parenchyma. The overall survival among these patients was not appreciably different from the survival of patients with the adult respiratory distress syndrome in general.

Acute Disease↗
PubMed1990

Ventilatory control during exercise in calves with artificial hearts.

To determine the role of cardiac reflexes in mediating exercise hyperpnea, we investigated ventilatory responses to treadmill exercise in seven calves with artificial hearts and seven controls. In both groups, the ventilatory responses were adequate for the metabolic demands of the exercise; this resulted in regulation of arterial PCO2 and pH despite the absence of cardiac output increase in the implanted group. In this group, there was a small but significant reduction of arterial PO2 by 4 +/- 3 Torr and a rise of blood lactate by 1.1 +/- 1 mmol/l. When cardiac output was experimentally increased in the implanted calves to a level commensurate with that spontaneously occurring in the control calves, ventilation was not affected. However, experimental reductions of cardiac output led to an immediate augmentation of exercise hyperpnea by 4.56 +/- 4.3 l/min and a further significant lactate increase of 1.2 +/- 1.22 mmol/l that was associated with a significant decrease in the exercise O2 consumption (0.32 +/- 0.13 l/min). These observations indicate that neither cardiac nor hemodynamic effects of increased cardiac output constitute an obligatory cause of exercise hyperpnea in the calf.

Animals↗
PubMed1990

Reference equations used to predict pulmonary function. Survey at institutions with respiratory disease training programs in the United States and Canada.

Adult respiratory disease training programs in the United States and Canada were surveyed to determine which reference equations were used to predict normal pulmonary function and how ethnic differences were approached. Replies from 139 of the 180 (77.2 percent) institutions surveyed were received and evaluated. Surprisingly few studies account for most of the equations in use: three studies account for 85 percent of the spirometric equations, two for 83 percent of the lung volume equations and five for 84 percent of the diffusing capacity equations. Although there are no definite data, the form of many of the replies suggests that equipment default settings may influence the selection process. Of those responding to the ethnic difference question, 53 percent of institutions applied no correction for ethnic differences. There was no consistent pattern to the method of correction among those who did.

Canada↗
PubMed1990

Normal spirometric values in healthy Hispanic Americans.

FVC, FEV1, FEV1/FVC, and FEF25-75% were measured in 259 (116 men and 143 women) healthy nonsmoking Hispanic American volunteers from Utah and California. Linear regression equations were created for women greater than or equal to age 20 years and men greater than or equal to age 25 years using height, age, and weight as independent variables and the spirometric indices as dependent variables. Weight was a significant predictor only for female FEV1. The raw data from this study were compared with data from our previous studies in North American Indians and Salt Lake City whites with Middle European ethnic backgrounds. No differences were found for any of the age and height coefficients. The only differences found were in the comparisons of the equation intercepts (bias) for male FVC and FEV1 between data for the Salt Lake City white subjects and both Hispanic American and North American Indian men. These small biases could be explained by technical or sampling biases or they may represent small ethnic differences. Although the differences from our Salt Lake City study are small, we recommend that ethnic-specific equations be used where they are available.

Adolescent↗