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Biomedical subjects

P B Terry

Publications and source records attributed to P B Terry.

At least 73 records · Page 4Linked to original sources
PubMed1982

Effects of positive end expiratory pressure on shunt flow in atelectasis.

We studied the effects of positive end expiratory pressure (PEEP) on vascular pressure flow relationships in atelectatic lobes in the closed-chest pigs and compared our results to measurements we previously obtained in sublobar atelectasis. Regional hemodynamic responses to lung inflation were significantly different between lobes and sublobar regions. PEEP caused marked increase in the fraction of cardiac output perfusing the atelectatic lobe from 16.5 +/- 2.0% (SE) to 32.5 +/- 2.0% at similar pulmonary vascular transmural pressures. In contrast, similar levels of PEEP failed to redistribute blood flow to the atelectatic sublobar regions. We propose that distortion of the sublobar region with inflation of the surrounding lung may be responsible for the failure of redistribution of pulmonary blood flow with application of PEEP.

Animals↗
PubMed1982

Embolotherapy of pulmonary arteriovenous malformations with detachable balloons.

Multiple pulmonary arteriovenous malformations (PAVM) present a difficult management problem, since surgical resection is not feasible in most instances. Embolotherapy offers a viable alternative. Over a 2-year period, the authors used detachable balloons to treat 16 PAVMs in 5 patients, of whom 4 had severe hypoxemia and 1 had hemoptysis. Symptomatic improvement was achieved in all but 1 patient, in whom the largest PAVM could not be occluded because the balloon was too small. Two patients exhibited segmental pulmonary infarctions. Follow-up angiograms 4 months and 2 years after occlusion demonstrated persistent obliteration of 14 PAVMs without development of collateral supply; 2 required re-embolization due to enlargement of existing nonoccluded feeders. The authors feel that balloon embolization is a safe and effective treatment of PAVMs.

Adult↗
PubMed1982

Mechanical factors and the regulation of perfusion through atelectatic lung in pigs.

The role of mechanical interdependence in the perfusion of atelectatic lung was studied in two ways: a) regional hemodynamics were compared before (control) and after the development of lobar and sublobar atelectasis, and b) the effect of thoracotomy on regional hemodynamics was assessed. With lobar atelectasis mean lobar blood flow and vascular conductance decreased to 60% of control. Sublobar atelectasis caused mean sublobar blood flow and vascular conductance to decrease to 6% of control. Opening the chest after production of lobar atelectasis caused blood flow to fall to 50% of control. When sublobar atelectasis was produced in the open chest, sublobar blood flow decreased to 25% of control measurements made prior to thoracotomy. We conclude that with a closed chest, sublobar vascular distortion mediated by mechanical interdependence may be an important mechanism responsible for the differences in hemodynamic responses to atelectasis between lobes and sublobar regions.

Animals↗
PubMed1982

Clinical decision making with transbronchial lung biopsies. The value of nonspecific histologic examination.

To investigate the importance of fiberoptic bronchoscopy with transbronchial biopsy (TBB) in clinical decision making, we reviewed 242 consecutive TBB procedures with respect to clinical presentation, roentgenographic pattern of disease, bronchoscopy result, and patient outcome. The specific yield of TBB was greatest in patients with multilobar disease and suspected sarcoidosis, metastatic neoplasm, or opportunistic infection. The value of a nonspecific TBB was estimated from its influence in changing clinically-derived suspicions of disease. Using pretest probabilities based on prebronchoscopic suspicions and likelihood ratios derived from our TBB results, Bayes's theorem was applied to estimate posttest probabilities. Nonspecific TBB reduced the probability of granulomatous pneumonitis. However, only small differences in posttest probabilities were associated with this bronchoscopy result in other patients with multilobar infiltrates, and no differences were observed in those with localized disease.

Biopsy↗
PubMed1981

A continuing medical education program in chronic obstructive pulmonary diseases: design and outcome.

A continuing medical education course was developed to improve the care of patients with chronic bronchitis and emphysema (COPD); 44 primary care physicians completed the course. The physicians were randomly assigned to experimental and control groups, with 3 of the 4 experimental groups assisting in the selection of topics for the programs and/or receiving feedback on tests given during the course. The course's impact was assessed using written tests to measure knowledge and simulated patient visits to observe physician performance. Experimental groups retained significantly greater amounts of information 9 months after completing the program and used more program material during patient visits than did the control group (p < 0.05). The test scores and patient visits of the 3 experimental groups involved in determining the audiovisual topics and/or receiving feedback were not significantly different from one another nor from the fourth experimental group.

Audiovisual Aids↗
PubMed1981

Fatal lung abscesses: review of 11 years' experience.

A review of the outcome of 440 patients hospitalized between 1967 and 1977 because of lung abscess showed that 41 died (case fatality rate = 9.3%). Major predisposing factors were present in many of the fatal and nonfatal cases. Advanced age and concomitant diseases were associated with a higher risk of death. Aspiration of contents of large cavities may have played a major role in the death of seven patients.

Adult↗
PubMed1981

Transbronchial needle aspiration for diagnosis of lung cancer.

Thirty-two consecutive patients with mediastinal lesions suggestive of bronchogenic carcinoma underwent transbronchial needle aspiration. Eighteen of 20 patients (90 percent) with proved bronchogenic carcinoma had malignant cytology specimens or tissue fragments. Of 12 patients with normal cytology specimens, six were subsequently proved to have nonneoplastic disease. Transbronchial needle aspiration appears to offer a sensitive and specific alternative to more invasive surgical techniques used in the diagnosis of malignancies with mediastinal involvement.

Biopsy, Needle↗
PubMed1980

Analysis of ethnic differences in perinatal statistics.

The 3996 mothers delivered at Dudley Road Hospital, Birmingham, in 1979 were analysed for their ethnic origins. Social classes IV and V predominated in all groups. A high proportion of Indian mothers fell into the low-risk group based on age and parity but had the highest stillbirth and perinatal mortality rates (15.1 and 27.5/1000 respectively) and infants of low mean birth weight (2986 g). Elderly and multiparous mothers were characteristic of the Pakistani and Bangladeshi groups. Young, primiparous mothers were more common among the West Indians and Europeans, in whom the stillbirth and perinatal mortality rates were low; infants in the European group had a mean birth weight higher than in any other group (3231 g). From these findings ethnic origin of the mother is apparently an important factor in perinatal mortality.

Bangladesh↗
PubMed1980

Comparison of standard and large forceps for transbronchial lung biopsy in the diagnosis of lung infiltrates.

In order to determine whether larger biopsy forceps improve the diagnostic yield over smaller standard forceps, we performed 30 transbronchial biopsy procedures in 28 patients with lung infiltrates using three types of instruments. We found that compared to the standard forceps specimens the large forceps acquired larger specimens in 22 of 29 procedures and that the alligator forceps acquired larger specimens in 7 of 10 procedures. However, in only 2 of the 29 procedures did the larger biopsy specimen alter the pathologic diagnosis. Four of the patients subsequently underwent open lung biopsy which did not alter the pathologic diagnosis rom the transbronchial biopsy procedure. We conclude that the large forceps do not significantly improve the diagnostic yield of transbronchial biopsy in our patients.

Biopsy↗
PubMed1980

Computed tomography of the bronchi: 1. Normal anatomy.

This report demonstrates the normal cross-sectional appearance of the bronchial tree as seen on computed tomography. Key sections are emphasized in order to provide general orientation. Where significant, anatomic variations are identified. Detailed knowledge of the normal appearance of the bronchi is a prerequisite to identifying abnormalities that affect both the bronchi and the hilum.

Bronchi↗
PubMed1980

Computed tomography of the bronchi. 2. Pathology.

Computed tomography (CT) can be used to diagnose both inflammatory and neoplastic diseases that arise from or affect the bronchi. The clarity of anatomic detail that can be obtained with CT is demonstrated. This clarity of anatomic detail should be of use in those cases for which bronchoscopy, mediastinoscopy, or other staging procedures are planned. The overall usefulness of CT in patients with bronchial lesions has yet to be established.

Bronchial Neoplasms↗
PubMed1980

Effect of lung volume on collateral ventilation in the dog.

We studied the effect of lung volume on resistance through collateral pathways (Rcoll) and small airways (Rsaw) before and after the injection of methacholine into obstructed segments of intact dogs. Before methacholine, Rcoll decreased 15.0 +/- 4.9 (SE)% per cmH2O increase in transpulmonary pressure (Ptp) and Rsaw decreased 5.1 +/- 7.0 (SE)% per cmH2O increase in Ptp. Following methacholine, lung inflation resulted in similar decreases in Rcoll and Rsaw. The fall in Rcoll was significantly greater than the fall in Rsaw. When pressure in an obstructed segment (Ps) was increased with constant Ptp (nonhomogeneous inflation), Rcoll fell approximately half as much for each cmH2O increase in pressure compared to when Ptp was increased (homogeneous inflation). We conclude 1) that increases in lung volume have small effects on Rsaw so that there is a relative increase in flow through collateral channels serving obstructed poritons of lung and 2) that Rcoll is a function of the size of the obstructed segment that increases more under homogeneous than nonhomogeneous conditions.

Airway Resistance↗
PubMed1980

Catamenial pneumothorax: evaluation by fiberoptic pleuroscopy.

A patient with catamenial pneumothorax and pelvic endometriosis underwent pleuroscopic examination with the flexible bronchoscope. For the first time, using this technique, diaphragmatic defects were observed, and the passage of air through them from the peritoneum to the thoracic cavity was documented.

Adult↗
PubMed1979

Effects of lung volume on collateral and airways resistance in man.

The effects of changing lung volume (VL) on collateral resistance (Rcoll) and total airways resistance (Raw) were compared in six young volunteers. At functional residual capacity (FRC) = 55% total lung capacity (TLC), mean Rcoll was 4,664 +/- 1,518 (SE) cmH2O/(l/s) and mean Raw was 1.57 +/- 0.11 (SE) cmH2O/l/s). When VL increased to 80% TLC, Rcoll decreased by 63.3 +/- 7.8%, and Raw decreased by 50.3 +/- 4.2 (SE) %. The decrease in Rcoll with increasing lung volume was not statistically different from that of Raw (P less than 0.05). If the airways obstructed for measurements of Rcoll served between 2 and 5% of the lungs, then Rcoll was approximately 50 times as great as the resistance to flow through airways serving the same volume of lung at FRC. The relationship did not change significantly when VL increased by 25% TLC. If changes in Raw reflect changes in airways supplying sublobar portions of lung, these results indicate that there is no tendency for the redistribution of ventilation through airways and collateral pathways with changes in VL in young subjects.

Adult↗
PubMed1979

Effects of methacholine and hypocapnia on airways and collateral ventilation in dogs.

We studied the effects of hypocapnia and methacholine on small airways resistance (Rsaw) and collateral ventilation in anesthetized paralyzed dogs. The animals were ventilated with air while either 10% CO2 or air (hypocapnia) was infused through a segment obstructed with a fiber-optic bronchoscope. Measurements were made before and after instillation of methacholine into the obstructed segment. Collateral resistance (Rcoll) and Rsaw increased with hypocapnia and methacholine. The time constant for collateral ventilation increased with hypocapnia, but did not change with methacholine because of decreases in the compliance of the obstructed segment. We conclude that collateral channels respond to methacholine and hypocapnia in a manner similar to small airways and that local parasympathomimetic stimulation, unlike lung deflation does not increase the time constant for collateral ventilation.

Airway Resistance↗
PubMed1979

Sublobar atelectasis and regional pulmonary blood flow.

We studied the effects of sublobar atelectasis on regional blood flow in anesthetized paralyzed pigs. Following the washout of nitrogen from the lung with oxygen, a sublobar airway was obstructed and a peripheral segment of lung allowed to collapse. Blood flow to the atelectatic region fell from a control of 140.0 +/- 20.5 to 16.6 +/- 2.9 ml/(min . g). Basilar regions that became atelectatic spontaneously during the course of the studies had similar decreases in blood flow. Inflation of the surrounding lung by the application of positive end-expiratory pressure failed to increase blood flow and vascular conductance within the atelectatic regions. These results indicate that mechanical and hypoxic effects on vessels perfusing sublobar atelectatic regions limit the effects of interdependence from the surrounding lung. Furthermore, with inflation of the surrounding lung, increases in pulmonary shunting of blood are small.

Animals↗