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Biomedical subjects

R G Hooper

Publications and source records attributed to R G Hooper.

At least 19 recordsLinked to original sources
PubMed1996

Established adult respiratory distress syndrome successfully treated with corticosteroids.

In 1990, we described the treatment of established adult respiratory distress syndrome (ARDS) with a sustained course of adrenocortical steroids (ACS). This report updates our experience with an uncontrolled prospective series. Patients with ARDS of more than 3 days' duration were initially given ACS in intravenous dosages of 125 to 250 mg every 6 hours, with tapering every 3 to 4 days. ARDS was present for 3 to 40 days before treatment. The PO2/FIO2 ranged from 45 to 211 (mean, 109) and the injury index from 2 to 4 (mean, 3.25). Nineteen gallium Ga 67 citrate lung scans were obtained in 18 patients. The scans showed diffuse abnormality in all 19 studies, but added no new diagnostic information. We have treated 26 patients, and overall survival was 81% (21/26). When complicating features were present, survival was 64% (9/14). Our uncontrolled, observational experience in treating established ARDS suggests that a sustained course of ACS may improve survival in these severely ill patients.

Adult↗
PubMed1995

Mitochondrial enzyme deficiency causing exercise limitation in normal-appearing adults.

Deficiencies of mitochondrial enzymes cause a number of severe neurologic syndromes in pediatric patients. Isolated myopathy secondary to enzymatic deficiency only rarely has been recognized and reported in adults. Three normal-appearing patients with unexplained dyspnea on exertion, tachycardia, and fatigue were studied with progressive incremental and constant load exercise testing with hemodynamic and gas exchange measurements. Subsequently, muscle biopsies were performed and enzymatic profiles determined. Exercise testing suggested altered cellular energy metabolism. Oxygen transport and gas exchange at rest and with exercise were normal. During exercise, ventilation increased excessively for the work performed, but it was appropriate for carbon dioxide production. Cardiac outputs increased significantly (196 to 305%), heart rates reached maximum levels, and lactic acid levels increased (385 to 833%) during exercise at 25 W. Muscle morphology was normal, but mitochondrial enzyme assays demonstrated one or more deficiencies in all three patients. Mitochondrial enzymatic deficiency can be a cause of unexplained exercise symptomatology and limitation in adults. Our experience would suggest the incidence of the disorder may be greater than that previously recognized or expected. Symptoms of exercise limitation associated with dyspnea, tachycardia, or muscle fatigue should alert the clinician to a possible abnormality in cellular energy metabolism.

Adult↗
PubMed1993

Massive airway leaks: an analysis of the role of endotracheal tubes.

OBJECTIVE: To determine the abnormalities present in endotracheal tubes removed from mechanically ventilated patients for "massive airleak." "Massive airleak" was defined as a leak that the attending physician felt was indicative of endotracheal tube defect such that extubation (and reintubation, if needed) would be indicated. DESIGN: Prospective, observational study. SETTING: Mixed medical-surgical intensive care unit at a community teaching hospital. PATIENTS: Seventeen patients among 1,082 patients who were undergoing mechanical ventilation during the study period. INTERVENTIONS: Authors were not involved in the evaluation of most airleak situations and most participating physicians were unaware of the study. All physicians involved were board certified in pulmonary, critical care, emergency medicine, or anesthesiology. Removed endotracheal tubes were grossly inspected and subjected to pneumatic stress to determine the sites of the leakage. MEASUREMENTS AND MAIN RESULTS: Eighteen endotracheal tubes were examined over a 2-yr period. Of these tubes, 11 (61%) had no evidence of mechanical fault. Five (28%) tubes had defects in the tracheal cuff and two (11%) tubes had abnormalities of the pilot valve apparatus. Condensation within the pilot valve cuff was present in 14 of 18 tubes and was present in ten of 11 intact tubes. Although the study population had an equal number of orally and nasally placed endotracheal tubes, intact tubes were disproportionately oral (8/11) and tubes wtih cuff leaks were predominantly nasal (4/5) (p = .038). CONCLUSIONS: A large number of endotracheal tubes removed for presumed defect are flawless. The authors speculate that tube malposition is the most likely explantation for this phenomenon. Our findings suggest that patient care might improve with more meticulous daily attention to the airway, as well as a more analytical rather than action-oriented approach to the leaking endotracheal tube.

Equipment Failure↗
PubMed1990

Established ARDS treated with a sustained course of adrenocortical steroids.

Short treatment courses of ACS have been shown to be of no demonstrable value in the treatment of ARDS. We gave two patients with persistant ARDS a trial of ACS after they demonstrated pulmonary uptake of 67Ga. Brief initial improvement disappeared with tapering of the ACS. A sustained course of ACS led to resolution of the ARDS in both patients. In all, ten patients with established ARDS were treated with sustained ACS over an 18-month period. The eight additional patients had uninterrupted courses of therapeutic ACS for greater than 21 days. The patients averaged 12 days of greater than 40 mg a day. At the time of treatment, all patients had established ARDS, meeting for at least 72 hours, criteria for the diagnosis of ARDS. A sustained course of ACS may be effective in the treatment of selected patients with established ARDS. Controlled studies of established ARDS are indicated to define the characteristics of these patients and their management.

Adrenal Cortex Hormones↗
PubMed1988

Endobronchial electrocautery.

Endobronchial electrocautery is a tool with diagnostic and therapeutic applications in the management of obstructing endobronchial disease. We have performed cautery procedures in 18 patients. Of these 18, five patients had benign diagnoses and 13 had malignancies. All patients with benign lesions had only endobronchial resections and four have done well. Four procedures resulted in the establishment of a diagnosis which had eluded other biopsy techniques. In 11 patients with malignant disease, electrocautery was used for palliation of airway obstruction, and in two patients, the snare was used as a biopsy technique. There have been no complications while utilizing the snare; however, application of electrocautery probes was associated with two complications. Our experience demonstrates the value and safety of using cautery wire snares to diagnose and treat endobronchial lesions.

Bronchial Diseases↗
PubMed1987

Evaluation of the risk for drug-induced postural hypotension in an experimental model: investigations with carvedilol, prazosin, labetalol, and guanethidine.

Postural hypotension is a common side effect observed in the treatment of hypertension with various drugs. Carvedilol, a vasodilating beta-blocker, was compared with prazosin, labetalol, and guanethidine for its ability to induce orthostatic hypotension. The comparison was carried out using doses of the drugs required to lower baroreceptor reflex hypertension in anesthetized rabbits by 30 mm Hg (ED -30 mm Hg). The following doses were found in independent investigations to be equipotent in this rabbit model: ED -30 mm Hg (mg/kg i.v.): prazosin = 0.03; labetalol = 1.8; guanethidine = 0.12; carvedilol = 0.12. These doses did not markedly inhibit the orthostatic reaction in rabbits after tilting stress, so 10-fold higher doses were used and clear discrimination between the drugs was found. The orthostatic index was reduced after prazosin and labetalol by about 24%, after guanethidine by about 30%, and after carvedilol by about 13%. The 50-fold dose of carvedilol (6 mg/kg i.v.) does not lead to any greater inhibition of the orthostatic index. From these results it is concluded that a relatively lower risk of postural hypotension is to be expected after carvedilol treatment than with the other drugs presented here. Furthermore, these results do not provide any indication that carvedilol exerts its vasodilator properties via alpha-blockade.

Animals↗
PubMed1987

Chronic right heart failure: pulmonary considerations.

Right ventricular failure is a frequent companion of chronic pulmonary disease, particularly that associated with chronic desaturation. Increases in right ventricular after-load will occur as the result of a number of mechanisms, many of which are present in the face of altered pulmonary physiology. To assess the role of pulmonary disease in the development of chronic right failure, one needs a knowledge of the physiologic effects of the respiratory process in each individual. Is the physiologic profile appropriate to be associated with cor pulmonale? Advances in understanding control of breathing, sleep-disordered breathing, and exercise contribute to clarifying the clinical picture of many patients with chronic right heart failure. In these patients, changes in afterload continue to be the central predominant problem.

Chronic Disease↗
PubMed1985

Acid-base changes and ventilator mode during maintenance ventilation.

Assist-control ventilation was compared to intermittent mandatory ventilation (IMV) for respiratory support of 35 patients without known respiratory disease, who had undergone coronary bypass surgery. Spontaneous respiratory rates and minute ventilation did not differ significantly between the two groups. Blood gas samples obtained during the assist-control mode had a significantly lower PaCO2 and higher pH than blood gases measured during high-rate IMV. There were six cases of severe alkalemia during assist-control ventilation, all respiratory in origin. These were attributable to the higher respiratory-rate settings and the extra respirator-delivered tidal volumes when spontaneous rates were higher than the set rates. IMV was associated with fewer ventilator-induced acid-base changes.

Acidosis, Respiratory↗
PubMed1985

Endobronchial electrocautery.

Endobronchial electrocautery was successfully used to treat three patients with major airway obstruction resulting from bronchogenic carcinoma and to establish a diagnosis in a fourth. Electrocautery was applied through fiberoptic bronchoscopes. In two cases, a wire snare was used to remove polypoid lesions and in two others, probes were used to ablate tumor tissue. As a result of high inspired oxygen concentration in one patient, a tracheal fire occurred without injury to the patient. Electrocautery is an available economical tool which has potential value in the diagnosis and therapy of endobronchial obstructing airway lesions.

Aged↗
PubMed1984

Endobronchial electrocautery. A role in bronchogenic carcinoma?

Progressive respiratory failure due to massive endobronchial involvement causes death in some patients with bronchogenic carcinoma. The absence of satisfactory therapeutic modalities directed specifically at masses of endobronchial tumor has limited our ability to effectively palliate these patients. Electro-cautery is a technique which has the potential for removing large quantities of endobronchial tumor safely, painlessly , and without measurable blood loss. It is especially well suited to the patient requiring local palliation with immediate relief of airway obstruction and without a prolonged hospital stay. The report reviews: a) its use in an individual with tracheal obstruction; b) the effect of electrocautery current changes and probe type on canine trachea; and, c) the technical problems which must be considered in using endobronchial electrocautery. In the individual with tracheal obstruction, large amounts of tumor were cleared with excellent hemostasis. The canine trachea demonstrates that the amount and duration of current used are extremely important. Equipment available of gastrointestinal electrocautery can produce significant tracheal damage and must be used with great caution. Finally, fiberoptic bronchoscopes are not designed for electrocautery work, and care must be employed when performing such procedures through these instruments.

Animals↗
PubMed1984

Computed tomographic scanning of the brain in initial staging of bronchogenic carcinoma.

Hematogenous dissemination to the brain occurs frequently with bronchogenic carcinoma ( BGCA ). Advocates of computed tomographic (CT) scanning have proposed the use of CT scanning of the brain as a screening procedure to exclude metastasis. To establish CT's appropriate role, we have retrospectively reviewed patients who had CT scanning of the brain during the initial staging and evaluation of BGCA . Clinical factors indicative of metastatic disease, both organ-specific and nonorgan -specific, were extracted from the history, physical, and laboratory data. Eighty-nine patients were studied. Sixteen patients had abnormal CT scans of the brain (18 percent). Only nine of the 16 had evidence of central nervous system (CNS) disease on history or physical examination. All 16 patients had strong clinical indications of disseminated disease. With completely normal clinical examinations, no abnormal CT scans were identified. Among patients with three or more clinical abnormalities present, an abnormal CT scan occurred in 37.5 percent (12 of 32). The clinical examination is a sensitive indicator of metastatic CNS disease as identified by the CT scan. Both organ-specific and nonorgan -specific findings are important indicators of CNS metastatis .

Adult↗
PubMed1983

Exercise testing in pulmonary sarcoidosis.

The variable natural history of sarcoidosis and the toxicity of corticosteroids result in many clinical situations where there is controversy concerning the need for treatment. Progressive incremental testing is an excellent method to identify physiologic mechanisms responsible for exercise limitation. It is therefore ideal to determine if subjective symptoms such as dyspnea are due to cardiac abnormalities, pulmonary abnormalities, or poor physical conditioning. Thirty-one patients with sarcoidosis underwent progressive incremental exercise testing. Four of 14 asymptomatic patients and eight of 17 symptomatic patients demonstrated pulmonary abnormalities which potentially limited exercise tolerance. These consisted of an abnormal respiratory pattern or gas exchange abnormalities, or both. Patients with completely normal routine pulmonary function studies almost always performed normally with exercise. Symptomatic patients with multiple abnormalities on routine pulmonary function studies invariably demonstrated a pulmonary limitation on exercise testing. Patients with one or two abnormalities on routine pulmonary function studies, regardless of the presence or absence of parenchymal infiltrates, required exercise testing to determine if symptoms were due to physiologically significant abnormalities of the respiratory system. The important variables necessary to be measured, arterial desaturation and an abnormal respiratory pattern, can be measured noninvasively with a minimum of equipment.

Adrenal Cortex Hormones↗
PubMed1982

Indications for mediastinal lymph node evaluation.

Successful surgical therapy for bronchogenic carcinoma depends upon an accurate lymph node assessment. Criteria were developed and reported to identify patients who would benefit from mediastinoscopy prior to thoracotomy. This report summarizes the prospective use of the criteria between 1974 and 1977 and the total experience from 1970 to 1977. Selection of patients for prethoracotomy mediastinal evaluation is primarily based on chest roentgenogram and cell type. Left upper lobe lesions meeting the criteria were submitted to mediastinotomy if mediastinoscopy was negative. Eighty-seven potentially resectable lesions were evaluated prospectively, and the total experience included 202 patients. Mediastinal metastasis occurred in 39 patients of the current and 82 patients of the total series. When metastases to the mediastinum were documented, roentgenographic evidence of metastasis was seen in 20 of 39 (51 percent) of the current and 44 of 82 (54 percent) of the total series. There was roentgenographic evidence of metastasis in central lesions, peripheral masses, and small peripheral lesions with mediastinal metastases in 50 percent, 25 percent, and 78 percent of the cases, respectively. Mediastinal metastases were reported 80 percent of the time before thoracotomy using these criteria. The use of mediastinotomy on left upper lobe lesions identified six of seven of the unresectable cases missed by the mediastinoscopy. The criteria will identify patients at high risk for mediastinal metastases who benefit from prethoracotomy surgical evaluation.

Adenocarcinoma↗
PubMed1980

Bullous emphysema. Progressive incremental exercise testing to evaluate candidates for bullectomy.

Various tests of both function and anatomy have been used in patients being considered for surgical resection of giant pulmonary bullae. A young patient had an excellent response to removal of a large bulla in the right lung. In addition to roentgenographic evaluation, ventilation perfusion scanning, and routine preoperative pulmonary function studies, we performed progressive incremental exercise testing to determine both preoperative and postoperative ventilatory and cardiac measurements. We feel that progressive incremental exercise pulmonary function adds another dimension to the selection and follow-up of patients being considered for operative bullectomy.

Adult↗
PubMed1980

Pulmonary infiltrates in leukemia.

We reviewed the inpatient records of 139 adult patients with leukemia to determine the incidence of opportunistic infections in immunocompromised patients and the pattern of roentgenographic involvement of such infections. There were 98 parenchymal infiltrates identified, including 43 episodes of local disease and 55 episodes of diffuse disease. The causes of the infiltrates were determined from biopsies of tissue and autopsies whenever possible. If roentgenographic resolution after therapy with an antibiotic or diuretic agent was documented, the cause was considered determined; however, this did not identify a specific bacterial or viral agent. Parenchymal infiltrates (17 episodes) appearing in the period before treatment or within 72 hours of initiating therapy were not opportunistic. Local disease during treatment was infectious in 23 (74 percent) of 31 cases and was bacterial in 20 (87 percent) of 23 cases. Opportunistic organisms caused only 13 percent of the local infectious episodes. Diffuse disease was noninfectious in 26 (65 percent) of 40 episodes; while in the 14 episodes of infectious disease identified, 13 (93 percent) were caused by opportunistic organisms. We conclude that procedures for biopsy to document opportunistic infection are of little value in local or diffuse disease before treatment, are of modest value in local disease during treatment, and are of greatest value in diffuse disease during treatment if little clinical evidence for noninfectious causes exists.

Acute Disease↗