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Biomedical subjects

D J Powner

Publications and source records attributed to D J Powner.

At least 19 recordsLinked to original sources
PubMed1990

Hormonal changes in brain dead patients.

Thirty neurologically impaired (Glasgow Coma Score less than 7) patients were evaluated to determine if changes in serum levels of thyroid hormone, cortisol, insulin, or lactate suggest that replacement therapy is needed before removal of organs for donation. Serum levels of free thyroxine (fT4), thyroid-stimulating hormone (TSH), reverse T3 (rT3), cortisol, insulin, and lactate were monitored in 16 patients before and after brain death and in 14 additional patients who were similarly compromised but did not become brain dead. Low fT3, normal fT4, and normal or high rT3 as found in most patients were consistent with a variant of the euthyroid sick syndrome although TSH was elevated in some patients. Cortisol, insulin, and lactate levels were also normal or high. No correlation was found between low thyroid hormones and elevated lactate or the amount of vasopressor needed to sustain BP. No significant changes occurred in hormone or lactate levels after brain death. The explanation for an elevated lactate remains unclear but we do not believe this single finding justifies the diagnosis of a hypothyroid state in these patients or the administration of thyroid hormone to brain dead organ donors.

Adult↗
PubMed1986

Bacteriologic evaluation of the Servo 150 hygroscopic condenser-humidifier.

The Servo 150 hygroscopic condenser-humidifier was evaluated during use to determine if the inner foam core became contaminated and if a bacteria-laden aerosol was produced during the inspiratory cycle of the patient's mechanical ventilator. Cultures from the core and of inspired gas were obtained from seven patients with known culture-positive sputum, after 4, 8, 12 and 24 h of humidifier use. In each case, the inner foam core was grossly contaminated after 4 h of use and colony counts increased during the 24-h testing period. The bacteria recovered were the same as those cultured from sputum. Despite the core's heavy bacterial growth, a bacteria-laden aerosol occurred in only 43% of the samples obtained during humidifier use. The Servo humidifier does not appear to increase the risk of airway exposure to airborne bacteria during mechanical ventilation.

Bacterial Infections↗
PubMed1986

Procedures requiring signed consent. A survey of practice.

Despite extensive discussion of informed consent within the medical and legal literature, those diagnostic or therapeutic procedures which may specifically require written consent remain poorly identified. Survey results from 105 JCAH-approved hospitals show that 56 percent set forth a general policy statement regarding when and for which procedures consent is needed. The remaining hospitals specify individual procedures for which signed authorization is required by the hospital or medical staff guidelines. The potential liability, advantages and disadvantages of a general versus specific consent practice are discussed. A listing of those procedures itemized by responding hospitals from this national survey is also presented.

Consent Forms↗
PubMed1986

Brain death.

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Brain Death↗
PubMed1985

Bedside resuscitation bags: a source of bacterial contamination.

Resuscitation bags at the bedside of 12 intubated ICU patients with known culture positive sputum were evaluated as possible reservoirs of pathogenic bacteria. As oxygen was constantly flowing into the bags, sampling of gas continuously emitted from the exhalation valve assembly was sampled to detect if a bacteria-laden aerosol was being created. Positive cultures were obtained from 75% of the valves and 25% of the aerosol samples. In those patients with gram-negative bacteria in their sputum, 71% of the valves and 29% of the gas samples were positive for the same organisms. Various methods to control this possible contributing factor to nosocomial infection in the ICU are discussed.

Air Microbiology↗
PubMed1985

Effect of chest-tube suction on gas flow through a bronchopleural fistula.

Suction applied to a chest-tube drainage system produces subambient pressure within the chest tube and may increase or decrease the flow of gas passing from the airway through a bronchopleural fistula. Such gas may have participated in gas exchange and contain more CO2 and less O2 than inspired gas. Calculated or measured variables dependent upon exhaled CO2 and O2 will be erroneous unless the fistula gas values are considered. A device easily assembled from standard measuring instruments was used to titrate suction, thereby facilitating fistula closure and allowing more accurate physiologic assessment of gas content.

Adolescent↗
PubMed1985

Compression volume during mechanical ventilation: comparison of ventilators and tubing circuits.

Four ventilators (Puritan-Bennett MA-1 and MA-2, Emerson, and Bear I) and four commercially available disposable and nondisposable tubing circuits (Bennett nondisposable, Becton-Dickinson, Inspiron, and Life-line) were tested on a lung analog for differences in inspiratory-circuit compression volume. The compression ratio (Rc), equal to the gas volume compressed per cm H2O peak airway pressure, was calculated for each combination of ventilator and circuit at each of four compliance settings (0.15, 0.10, 0.05, 0.01 L/cm H2O) on the analog. Rc values ranged from 0.3 to 4.5 ml/cm H2O at the highest and lowest compliance settings, respectively, accounting for a reduction in delivered tidal volume of up to 20%. The Emerson ventilator with all tubing systems and the Bennett nondisposable circuit with each ventilator demonstrated slightly smaller compression volumes. Application of an inspiratory pause on the Bear I ventilator did not affect its compression characteristics. The clinical importance of compression volume and data from other ventilation systems are reviewed.

Humans↗
PubMed1976

Retroperitoneal air dissection associated with mechanical ventilation.

The radiologic patterns, etiology, and possible consequences of gas dissection into the retroperitoneal space from pulmonary sources are reviewed in three patients requiring mechanical ventilation. Airway disruption appears to be related to peak airway pressures, underlying pulmonary disease, and the patient's hemodynamic condition and may cause different forms of interstitial emphysema and air embolization, which may lead to severe respiratory or circulatory dysfunction. Gas migration to the retroperitoneum and, secondarily, into the peritoneal cavity should be considered in the differential diagnosis of free intra-abdominal gas.

Adolescent↗