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Biomedical subjects

B E Pennock

Publications and source records attributed to B E Pennock.

42 records · Page 3Linked to original sources
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Metabolic rate and weight loss in chronic obstructive lung disease.

Although weight loss is a common problem in chronic obstructive pulmonary disease (COPD), the precise cause of malnutrition in COPD patients is not known. The purpose of this study was to measure and compare resting energy expenditure (REE) in stable undernourished and adequately nourished COPD. REE was measured in normal, adequately nourished, and undernourished COPD patients by indirect calorimetry and then compared to predicted basal metabolic rate (BMR) calculated from the Harris-Benedict equation. We found that measured REE, compared to predicted, was significantly higher in the undernourished group, (1.15 +/- 0.02) and compared to the adequately nourished COPD (0.99 +/- 0.03) and normal groups (0.93 +/- 0.02) (p less than 0.0001). We conclude that there is a hypermetabolic state in stable malnourished COPD patients which may be a factor in weight loss. This elevated REE also needs to be taken into account when determining caloric requirements for COPD patients.

Adult↗
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Quantitative measurement of ventilation at the mouth and nose with heat sensors.

Airflow at the nose and mouth is routinely measured during polysomnography for the evaluation of respiratory disturbances during sleep. The usual monitoring device is a small thermocouple placed in front of the nose and mouth that qualitatively detects airflows in or out. A more accurate pneumotachometer on a tight-fitting mask is less frequently used because of the discomfort that is introduced and its potential interference with sleep. The authors tested ten heat-sensing devices modified to increase accuracy without increasing discomfort. The designs of these ventilation monitors differed in choices of specific heat detector, techniques of mounting on the face, and types of heat-trapping covers employed. The goal was to find a comfortable oronasal monitor and to define a procedure that could identify those units that generate signals approaching quantitative ventilatory flow. The signal from each device was compared with a "standard" signal derived from respiratory belts during contrived respiratory maneuvers that assessed specific potential sensing problems. The devices behaved differently, and design perturbations could be controlled to construct flow detectors to closely match actual flow. The more accurate devices could be as comfortable as commonly used monitors that do not have the enhanced accuracy. The principles and techniques described for improving the measurement of oronasal ventilation by heat sensor can be invoked to develop monitors that can closely measure actual quantitative ventilatory flow.

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Heterotopic lung transplantation: temporary biologic support for reversible pulmonary insufficiency.

BACKGROUND: The mortality rate resulting from adult respiratory distress syndrome in patients awaiting orthotopic lung transplantation remains high. Providing an "extra" lung may provide a potential solution to support a failing pulmonary system. We hypothesized that using a heterotopic lung transplant can correct hypoxemia and hypercarbia in both the short term and the long term. METHODS: Seven mongrel dogs underwent transplantation of a left lung into the abdomen. Anastomosis between the left atrial cuff and the pulmonary artery of the donor lungs was accomplished to systemic venous and arterial circulations, respectively. The main stem bronchus was exteriorized, intubated, and ventilated. Immunosuppression consisted of prednisone and azathioprine both preoperatively and postoperatively. Progressive levels of systemic hypoxemia and hypercarbia were induced. The heterotopic lung transplant augmented oxygenation with a tidal volume of 300 cc, a fraction of inspired oxygen of 50%, and a respiratory rate of 10 and then 20 breaths/min. Four animals were studied again at 48 hours. Flow through the heterotopic lung transplant ranged from 25% to 33% of the cardiac output. RESULTS: Statistically significant improvements were seen in both systemic oxygenation and ventilation in the short-term experiment. The systemic oxygen pressure improved from 37 +/- 3 mm Hg to 67 +/- 5 mm Hg after ventilation of the heterotopic lung transplant, and the carbon dioxide pressure improved from 56 +/- 1 mm Hg to 43 +/- 2 mm Hg. At 48 hours an improvement in oxygen pressure was noted after ventilation of the heterotopic lung transplant, from 42 +/- 3 mm Hg to 56 +/- 2 mm Hg and an improvement in systemic carbon dioxide pressure was noted after ventilation of the heterotopic lung transplant from 57 +/- 7 mm Hg to 46 +/- 4 mm Hg. CONCLUSIONS: The heterotopic lung transplant was able to provide effective gas exchange and support both oxygenation and ventilation after the induction of acute hypoxemia or hypercarbia, both immediately and at 48 hours after implantation. The heterotopic lung transplant may serve as an alternative mode of temporary support for those with acute respiratory insufficiency or as a bridge for those awaiting orthotopic lung transplantation.

Abdomen↗
PubMedDate not supplied

Distressful events in the ICU as perceived by patients recovering from coronary artery bypass surgery.

OBJECTIVE: To determine what events are perceived as most stressful to patients in the surgical intensive care unit (SICU). DESIGN: Descriptive cross-sectional survey. PATIENTS: One hundred twenty-seven patients who had undergone coronary artery bypass graft (CABG) at 48 hours after their transfer from the SICU. OUTCOME MEASURE: Stressful events as perceived by patients while in the SICU determined by 25 specific items on a questionnaire rated on a Likert scale ranging from 1 (no distress) to 4 (extremely distressful). RESULTS: Two stressors, being intubated and not being able to talk, were significantly more stressful, by Newman-Keuls multiple range test, than all the other stressors. The mean stressfulness score for all other stressors was between no distress and mild distress. CONCLUSION: Overall stress associated with specific events during a short stay in the SICU was minimal. Intubation and inability to communicate were the most stressful experiences.

Adult↗