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Biomedical subjects

D J Pierson

Publications and source records attributed to D J Pierson.

At least 19 recordsLinked to original sources
PubMed1992

Effects of pulmonary function of oral high frequency oscillation in normal and asthmatic subjects.

High frequency jet devices are not only used as 'internal percussors' to aid clearance of pulmonary secretions, but are also a mode of ventilatory support. As physical stimuli can cause bronchospasm in asthmatic individuals, we hypothesized that direct airway vibration may induce bronchospasm. To ascertain whether an airway vibration jet device could cause bronchoconstriction, we exposed eight asthmatic and six normal subjects to 5 min of jet-induced airway vibration or placebo treatment with cross-over at 3 h. Subjects breathed spontaneously for 5 min through an open mouthpiece into which either jet (10 Hz, 25 psi) or sham pulsations (same device, pressure vented to room at compressor) were delivered in a double-blind, random order. A constant-volume body plethysmography measured functional residual capacity and specific airway conductance (SGAW) and a water seal spirometer measured forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC). These pulmonary function measurements were taken before and at 5, 10, 20, 30, 60, 90 and 120 min after each exposure. In the normal subjects there was no significant change in any pulmonary function. There was not statistically significant change in the pulmonary function in the asthmatic patients. However, the oral high frequency oscillator induced a clinical asthmatic attack in one asthmatic patient. In this one patient, the FEV1 fell 35% from its initial value at 5 min following exposure to a maximum of 49% decline from initial value at 1 h following exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Cost reduction in diagnosing Pneumocystis carinii pneumonia. Sputum induction versus bronchoalveolar lavage as the initial diagnostic procedure.

Sputum induction (SI) is a sensitive and specific method for diagnosing Pneumocystis carinii pneumonia (PCP) in patients with AIDS. Although less expensive than bronchoscopy with bronchoalveolar lavage (BAL), SI followed by BAL does not necessarily reduce costs compared with BAL alone. Cost analysis demonstrates that the cost of diagnosing PCP is dependent on the prevalence of PCP (PCPprevalence) in the studied population, the sensitivity of SI (SIsensitivity) for diagnosing PCP, and the relative costs of SI and BAL (SIcost and BALcost) for diagnosing PCP. In any given clinical setting, SI reduces the cost of diagnosing PCP if (PCPprevalence)(SIsensitivity) greater than SIcost/BALcost. A graphic approach relating these parameters is also presented. Evaluation of reported PCPprevalence and SIsensitivity from recent literature illustrates that SI is not always the least costly method for diagnosing PCP. Cost reduction is not the only measure of a diagnostic procedure's value, and other aspects, such as discomfort, availability, risks, and patient prognosis, must be considered. The cost analysis approach used in this study identifies those variables that can be manipulated to reduce the cost of diagnosing PCP.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Pneumonia following closed head injury.

Pneumonia is common among patients with artificial airways in place. Most prior studies of such pneumonia involve a heterogeneous group of patients, usually with major medical or surgical illnesses. We studied the incidence of pneumonia in a group of patients with isolated closed head injury (CHI) in an effort to determine the pattern of the problem in the absence of other injuries and to determine whether the pattern of development of pneumonia in these patients was comparable to that in more heterogeneous groups of mechanically ventilated patients. We studied 109 initially comatose patients with isolated CHI who were ventilated 24 h or more. The mean age was 30.3 +/- 20.2 yr, 72% were male, and the admission Glasgow coma score was 4.9T +/- 1.4. Overall, 45 patients (41%) developed pneumonia, with the majority (29/45) occurring during the first 3 days of hospitalization. No patient developed pneumonia after the first week despite the fact that many were still ventilated, others remained intubated, and yet others were extubated but comatose. Patients who developed pneumonia experienced a longer ICU stay (10.5 +/- 5.4 days versus 7.2 +/- 4.3 days, p = 0.001) and hospital stay (34.8 +/- 27.6 versus 22.5 +/- 20.2 days, p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Efficacy of anticholinergic and beta-adrenergic agonist treatment of maximal cholinergic bronchospasm in tracheally intubated rabbits.

Cholinergically induced bronchoconstriction is thought to be a major cause of bronchospasm during anesthesia. We used tracheally intubated rabbits (4-mm endotracheal tube) stimulated with methacholine to assess the efficacy of beta-adrenergic agonist and anticholinergic treatment in reversing the increases in respiratory system resistance. Four groups were compared: (a) inhaled metaproterenol, 20 puffs via metered dose inhaler (0.65 mg/puff); (b) inhaled ipratropium bromide, 20 puffs from a metered dose inhaler (18 micrograms/puff); (c) 2 mg of intravenous atropine; and (d) no treatment after methacholine challenge as a control group. Methacholine increased respiratory system resistance from 0.041 +/- 0.001 (mean +/- SEM) to 0.098 +/- 0.006 cm H2O.mL-1.s-1 (P < 0.001). Whereas beta-adrenergic agonist treatment was ineffective in ameliorating bronchoconstriction, inhaled ipratropium bromide and atropine were highly effective, causing an 86%-88% reversal in the methacholine-induced increase in respiratory system resistance. Both these agents were also effective in improving dynamic compliance. We conclude that inhaled ipratropium bromide is effective in treating cholinergic bronchospasm even when administered via a small endotracheal tube and that the beta-adrenergic agonist metaproterenol is ineffective in rabbits in the face of maximal cholinergic stimulation.

Adrenergic beta-Agonists↗
PubMed1990

Pulse oximetry versus arterial blood gas specimens in long-term oxygen therapy.

Portable pulse oximeters are now widely available for the assessment of arterial oxygenation, and the U.S. Medicare program considers saturation readings to be acceptable substitutes for arterial PO2 in selecting patients for long-term oxygen therapy (LTOT). Current oximeters are reasonably accurate (plus or minus 4 or 5 percent of the co-oximetry value), but the clinician should be aware of several potential problems. Readings may be inaccurate in the presence of hemodynamic instability, carboxyhemoglobinemia, jaundice, or dark skin pigmentation, and also during exercise. Indicated saturation may substantially overestimate arterial PO2 if the patient is alkalemic. Pulse oximetry cannot detect hypercapnia or acidosis. For these and other reasons, pulse oximetry should not be used in initial selection of patients for LTOT, as a substitute for arterial blood gas analysis in the evaluation of patients with undiagnosed respiratory disease, during formal cardiopulmonary exercise testing, or in the presence of an acute exacerbation. Pulse oximetry is an important addition to the clinician's armamentarium, however, for titrating the oxygen dose in stable patients, in assessing patients for desaturation during exercise, for sleep studies, and for in-home monitoring.

Blood Gas Analysis↗
PubMed1990

Complications associated with mechanical ventilation.

A constellation of adverse effects and complications may be associated with mechanical ventilation, although in many instances the causal role of the ventilator itself has not been established. Complications occur with greater frequency than is generally appreciated, and tend to be under-reported in the medical literature. Among the potential adverse physiologic effects of positive-pressure ventilation are decreased cardiac output, unintended respiratory alkalosis, increased intracranial pressure, gastric distension, and impairment of hepatic and renal function. Failure of the ventilator to cycle, of safety alarms to function properly, and of inspired gas to be properly heated or humidified are examples of equipment-related complications. Perhaps most feared among medical complications occurring during mechanical ventilation are pneumothorax, bronchopleural fistula, and the development of nosocomial pneumonia; these entities may owe as much to the impairment of host defenses and normal tissue integrity as to the presence of the ventilator per se. Finally, a variety of avoidable "misadventures," due primarily to lapses of understanding and communication among the physicians, nurses, and respiratory care practitioners managing the ventilated patient, can adversely affect comfort, morbidity, and ultimate outcome.

Cross Infection↗
PubMed1989

Home respiratory care in different countries.

Home respiratory care (provision of respiratory care services in patients' homes rather than in institutions or providers' offices) includes long-term oxygen therapy and home ventilatory assistance. I review the selection of patients, the role of physicians and other health care professionals, the types of equipment used, the administrative structures, and sources of payment or reimbursement in different countries. Because more has been published about home respiratory care in France and the United States, current practices in these two countries are reviewed in some detail; where available, information about long-term oxygen therapy and home ventilatory assistance in other countries is also included. As these and other modalities become more firmly established both scientifically and in clinical practice, and as technological advances continue to be introduced, home respiratory care will probably be made available to more patients, and in an increasing number of countries. Physicians, other health care workers, representatives of industry, administrative agencies, and those responsible for payment or reimbursement should work together to provide the best possible care of patients with chronic respiratory insufficiency.

France↗
PubMed1979

Acute lobar atelectasis: a prospective comparison of fiberoptic bronchoscopy and respiratory therapy.

To evaluate the usefulness of fiberoptic bronchoscopy for treatment of acute lobar atelectasis, 31 subjects were randomly allocated to fiberoptic bronchoscopy followed by respiratory therapy for 48 hours, or to respiratory therapy alone for the same period. No significant differences between groups with regard to restoration of volume loss were detected after the first treatment intervention, at 24 or at 48 hours (P greater than 0.20). Specifically, the mean percentage resolution of volume loss immediately after bronchoscopy (38 per cent) closely approximated that after the first respiratory therapy treatment in subjects who had not undergone bronchoscopy (37 per cent). An air bronchogram proved to be a predictor of delayed resolution for both groups. At 24 hours, 26 per cent of the air bronchograms demonstrated 83 per cent resolution (P less than 0.001). These results suggest that fiberoptic bronchoscopy does not add to respiratory therapy in the treatment of acute lobar atelectasis and that an air bronchogram predicts delayed resolution of collapse.

Adolescent↗
PubMed1979

The significance of wheezing in chronic airflow obstruction.

Eighty-three patients with chronic airflow obstruction were examined prospectively to determine the relationships among wheezing intensity, severity of obstruction, and response to inhaled isoproterenol. For each patient, expiratory wheezing scores were assigned during deep unforced breathing and during forced vital capacity efforts at spirometry. Unforced wheezing scores were independently correlated with severity of obstruction (r = 0.42) and bronchodilator response (r = 0.46), but these correlations did not permit consistent prediction of either variable for clinical purposes. The highest wheezing scores, however, were uniformly associated with moderate or severe obstruction. Twenty-nine of 48 patients with wheezing but only 3 of 35 patients without wheezing demonstrated 15% or greater improvement in one-second forced expiratory volume after bronchodilator inhalation (p less than 0.001). Wheezing during forced exhalation was not correlated with either degree of obstruction or bronchodilator response.

Aged↗
PubMed1979

Prolonged respiratory paralysis in wound botulism.

Two patients had wound botulism with longer duration of respiratory paralysis than previously described. Each sustained extensive trauma to soft tissues and grossly contaminated wounds when thrown from a vehicle in a rural area. Progressive muscular weakness and respiratory distress occurred 8 and 13 days after injury, in the presence of infected wounds and clinical and laboratory findings characteristic of botulism. Spontaneous vital capacity and inspiratory effort served as bedside indicators of ventilatory function throughout 11 weeks of ventilatory support in each case and paralleled other clinical assessments of progress and recovery. Wound botulism may result in neuromuscular paralysis for a prolonged period. These cases illustrate the primary role of scrupulous nursing and respiratory care throughout such a period of ventilatory insufficiency.

Adult↗
PubMed1978

Legionnaires' disease. Clinical and pulmonary histopathologic features of a sporadic case.

The pulmonary histopathologic features in a sporadic case of Legionnaires' disease are shown. The changes include acute bronchitis with focal ulceration and diffuse acute interstitial pneumonitis. These changes are not those seen with typical bacterial pneumonia but are similar to changes seen when viruses, rickettsiae, chlamydiae, or Mycoplasma pneumoniae organisms are the infecting agents.

Bronchitis↗
PubMed1978

Multiple plasmacytomas with thoracic and biliary involvement.

The course of a patient who had nonsecretory multiple myeloma was characterized by extraosseous plasmacytomas that were initially limited to pleural lesions with effusion and subcutaneous masses. Subsequently, we noted the development of obstructive jaundice caused by a mass at the head of the pancreas, which was diagnosed by abdominal ultrasound and responded to radiation therapy, and bilateral pulmonary nodules, which were visualized by fiberoptic bronchoscopy. Forceps biopsy of an endobronchial lesion showed plasmacytoma similar in histologic features to her original osseous lesions. The pulmonary nodules responded to cyclophosphamide and prednisone. During her course, she had three forms of intrathoracic myeloma: rib lesions extending into pulmonary tissue, pleural disease, and multiple endobronchial masses. The biliary and pulmonary manifestations of plasmacytomas are rarely seen. Diagnosis by noninvasive procedures and rapid response to conservative therapy were important in this patient's care.

Aged↗