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Biomedical subjects

G A Patterson

Publications and source records attributed to G A Patterson.

At least 145 records · Page 8Linked to original sources
PubMed1995

Bilateral pneumectomy (volume reduction) for chronic obstructive pulmonary disease.

We undertook surgical bilateral lung volume reduction in 20 patients with severe chronic obstructive pulmonary disease to relieve thoracic distention and improve respiratory mechanics. The operation, done through median sternotomy, involves excision of 20% to 30% of the volume of each lung. The most affected portions are excised with the use of a linear stapling device fitted with strips of bovine pericardium attached to both the anvil and the cartridge to buttress the staple lines and eliminate air leakage through the staple holes. Preoperative and postoperative assessment of results has included grading of dyspnea and quality of life, exercise performance, and objective measurements of lung function by spirometry and plethysmography. There has been no early or late mortality and no requirement for immediate postoperative ventilatory assistance. Follow-up ranges from 1 to 15 months (mean 6.4 months). The mean forced expiratory volume in 1 second has improved by 82% and the reduction in total lung capacity, residual volume, and trapped gas has been highly significant. These changes have been associated with marked relief of dyspnea and improvement in exercise tolerance and quality of life. Although the follow-up period is short, these preliminary results suggest that bilateral surgical volume reduction may be of significant value for selected patients with severe chronic obstructive pulmonary disease.

Adult↗
PubMed1995

Evaluation of a prototype esophageal detection device.

OBJECTIVE: To determine the ability of a prototype esophageal detection device (EDD) to identify esophageal misplacement of an endotracheal (ET) tube. METHODS: A prospective, randomized, blinded study of detection of esophageal intubation was conducted using 51 elective surgical patients who met inclusion criteria. A squeeze-bulb aspirator that creates a negative pressure of -80 to -90 torr was used for detection of esophageal intubation. The bulb should reinflate rapidly if the tube is in the noncollapsible trachea, but should not reinflate if the tube is in the collapsible esophagus. Each patient was prepared for surgery in the usual manner. The anesthesiologist placed an ET tube into the trachea. An identical tube was advanced the same distance into the esophagus. The tubes were labeled "A" or "B" according to a computer-generated random number list. An evaluator, who was blinded to the placement of the tubes, assessed one tube with the EDD. For most patients, a second evaluator, who was blinded to both tube placement and the results of the first evaluator, assessed the other tube. During evaluation, the tube cuffs were deflated. After data collection, the esophageal tube was removed and surgery was completed. RESULTS: All 45 esophageal tube placements were correctly identified. Thirty-five of the 40 ET tubes were correctly identified. Of the five ET tubes mislabeled, three were found in a mainstem bronchus. All had delayed bulb re-expansion. CONCLUSION: This prototype EDD is a useful method of identifying esophageal misplacement of an ET tube in anesthetized adult surgical patients.

Adolescent↗
PubMed1995

Bronchial dehiscence in lung transplantation: CT evaluation.

PURPOSE: To determine the signs of bronchial dehiscence on computed tomographic (CT) scans in a select subset of lung transplant recipients. MATERIALS AND METHODS: In 23 patients who underwent single or bilateral sequential lung transplantations, CT scans were obtained for suspected or known diagnosis of bronchial dehiscence. Dehiscence was identified at bronchoscopy in 17 of the 23 patients. In four patients, the dehiscence was bilateral, resulting in 21 anastomotic dehiscences. RESULTS: CT allowed identification of a bronchial defect in 100% of the bronchoscopically proved dehiscences but only one (5%) of the 18 bronchoscopically proved intact anastomoses. CT also demonstrated extraluminal air in 100% of the bronchoscopically proved dehiscences. Only a very small amount of extraluminal air (without associated bronchial defect) was identified on CT scans in the early postoperative period in four additional patients with bronchoscopically proved intact anastomoses. CONCLUSION: CT is an easily performed and well-tolerated technique that has a high degree of sensitivity and specificity for depicting bronchial dehiscence.

Adolescent↗
PubMed1995

Lung transplant edema: chest radiography after lung transplantation--the first 10 days.

PURPOSE: To determine the imaging spectrum and clinical correlates of lung transplant edema within the first 10 days after lung transplantation. MATERIALS AND METHODS: The study group consisted of 105 consecutive lung transplant recipients. Lung infiltrates on chest radiographs were scored and characterized. Findings that satisfied the accepted description of reperfusion edema were identified. Lung ischemia times and the clinical or biopsy diagnosis of acute rejection were correlated with radiographic findings. RESULTS: Lung infiltrates compatible with reperfusion edema were seen in 97% of transplanted lungs without a demonstrable correlation with lung ischemia times. Lung scores between groups of patients treated and not treated for acute rejection were not statistically significantly different. CONCLUSION: The spectrum of findings attributable to lung transplantation or reperfusion edema is variable and diminishes the use of chest radiography as an early postoperative modality for monitoring acute rejection.

Adult↗
PubMed1995

Seventy-two pulmonary retransplantations for obliterative bronchiolitis: predictors of survival.

BACKGROUND: Obliterative bronchiolitis (OB) occurs in up to 40% of patients in the intermediate term after lung transplantation. In recent years an increasing number of recipients with end-stage OB have been treated with retransplantation. METHODS: Seventy-two patients with OB underwent retransplantation at 26 North American and European centers a median of 590 days after their first transplant operation. The predictors of survival were determined using life table and Cox proportional hazards methods, and the recurrence rate of OB was determined in survivors. RESULTS: The actuarial survival rate was 71% +/- 5% at 1 month, 43% +/- 6% at 1 year, and 35% +/- 6% at 2 years; nonetheless, of the 90-day postoperative survivors, 63% +/- 7% were alive 2 years after retransplantation. Institutional experience with more than three pulmonary retransplantations (p = 0.008), reoperation in Europe (p = 0.013), donor-recipient ABO blood group identity (p = 0.018), and more recent year of retransplantation (p = 0.03) were associated with survival. On multivariate analysis, reoperation after 1989 (p < 0.001), retransplantation performed in Europe (p = 0.017), and being ambulatory immediately before reoperation (p = 0.022) were found to be predictive of a positive outcome. Pulmonary function test analyses confirmed that the forced expiratory volume in 1 second decreased from postoperative baseline values by 11% +/- 9% at 1 year and 27% +/- 10% at 2 years (p = 0.02; year 2 versus baseline). Fourteen percent of patients were in stage 3 of the bronchiolitis obliterans syndrome at 1 year postoperatively, with 33% affected at 2 years. CONCLUSIONS: The results of pulmonary retransplantation for OB are improving. Current evidence indicates that OB does not recur in an accelerated manner after retransplantation, although pulmonary function does worsen again by 2 years. Pulmonary retransplantation is appropriate only in selected patients with OB who are ambulatory and are operated on at experienced centers.

Adolescent↗
PubMed1995

Expression of class II major histocompatibility complex antigens (HLA-DR) and lymphocyte subset immunotyping in chronic pulmonary transplant rejection.

OBJECTIVE: Currently, the bronchiolitis obliterans syndrome (BOS) of chronic airway rejection represents the most significant obstacle to the long-term function of isolated pulmonary allografts in humans. Between 20% and 30% of recipients are affected by this condition. To define the possible pathogenetic role of altered expression of class II major histocompatibility complex antigens (ie, HLA-DR) in BOS, the authors studied well-characterized examples of this process immunohistologically. DESIGN: Eleven BOS specimens were compared with seven controls, represented by allografts with no pathologic abnormalities taken from patients with normal posttransplant respiratory function, as well as 14 biopsies showing acute rejection. In addition, immunophenotypic subtyping of lymphocytes in all specimens was undertaken. RESULTS: Control tissues exhibited variable but weak expression of HLA-DR in bronchiolar epithelium and alveolar pneumocytes. In comparison, immunostaining for class II major histocompatibility complex antigens in BOS showed no statistically significant differences, whereas the 14 examples of acute rejection manifested intense HLA-DR expression in epithelia and endothelial cells. The numbers of intrabronchiolar and peribronchiolar lymphocytes were clearly higher in both acute rejection and BOS than in controls, but these cells differed in lineage in the two rejection states. Acute rejection showed an obvious preponderance of CD43-positive T lymphocytes, whereas lymphoid cells in BOS were a relatively equal mixture of CD20-positive B cells and CD43-positive T cells. Moreover, incipient peribronchiolar B-cell follicles were observed in BOS. Natural killer (CD57-positive) lymphocytes were rare in all specimens. CONCLUSIONS: These data suggest that alterations in HLA-DR expression probably do not play a central role in the genesis of BOS, as they do in acute rejection. In contrast, the results of lymphocyte immunophenotyping and correlative histologic findings in BOS suggest that both T cells and B lymphocytes may be involved in the mechanism of chronic airway rejection.

Adult↗
PubMed1995

Lung-volume reduction surgery for severe emphysema.

The lung-volume reduction procedure is a palliative one, designed to relieve dyspnea, and improve the patient's ability to carry out routine activities of daily living without significant limitations. The rationale for this procedure and its development are discussed. In addition, patient selection, operative technique, postoperative care, results, and complications are considered. Ultimately, the value of lung-volume reduction surgery will be determined by the balance between the magnitude and duration of benefit achieved on the one hand versus the morbidity and mortality produced on the other.

Humans↗
PubMed1995

Lung transplantation for emphysema.

Lung transplantation is an established treatment option for patients with emphysema due to chronic obstructive pulmonary disease or alpha 1-antitrypsin deficiency. Operative mortality is low in experienced centers and functional results are acceptable. Morbidity associated with triple drug immunosuppression is significant. Constant annual death rates due to obliterative bronchiolitis and other complications result in a 50% 5-year survival; therefore, lung transplantation should only be offered to those ideal candidates who have no other treatment option.

Graft Rejection↗
PubMed1994

Effect of methylprednisolone on angiogenesis in syngeneic rat tracheal grafts.

Airway anastomotic complications remain a cause of morbidity after clinical lung transplantation. The use of corticosteroid therapy to control pulmonary rejection has raised concern over delayed airway healing. We therefore investigated the hypothesis that the effects of methylprednisolone (MP) impair the revascularization and epithelial regeneration of heterotopic syngeneic tracheal isografts. Lewis rat tracheal segments were wrapped in omentum and implanted in the abdomen of recipient rats. All recipients received cyclosporin A (CsA) (5 mg.kg-1.day-1) and were randomly allocated into three groups of 12 rats each according to the daily MP dose: group II, no MP; group III, 1 mg.kg-1.day-1; and group IV, 2 mg.kg-1.day-1. In each group, 6 animals were sacrificed after 7 and 14 days. Normal, untreated rats served as controls (group I). Epithelial regeneration was assessed histologically by a blinded subjective scoring system and by measurement of epithelial thickness. Tracheal revascularization was quantitated in terms of the number of blood vessels per square millimeter of tracheal wall and the vessel area was quantitated in terms of the percentage of the tracheal wall area. In animals treated with MP and CsA, the trachea exhibited significantly better regeneration after 14 days than it did in animals treated only with CsA. Epithelial regeneration was improved between 7 and 14 days in the groups treated with MP (group III, p = 0.01; group IV, p = 0.04). The epithelial thickness for all three study groups was significantly greater than that in the control group and returned toward normal after 14 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Changes in vascular permeability with ischemic time, temperature, and inspired oxygen fraction in isolated rabbit lungs.

The capillary filtration coefficient (Kf) is one of the most accurate measures of change in pulmonary vascular permeability and has been used in various models of acute lung injury. To evaluate the isolated effects of ischemia on Kf, we have developed an ex vivo rabbit lung model in which the influences of reperfusion are eliminated. The current study was designed to validate this model by determining the effect of cold flushing with low-potassium-dextran solution containing 1% glucose (LPDG), ischemic time, temperature, and inspired oxygen fraction on Kf. On completion of the ischemic period, the ventilated lungs, with the heart still attached, were suspended from a strain-gauge force transducer. After the lungs were flushed with 50 mL hetastarch solution (6% hetastarch solution with physiologic saline solution), the left atrial drainage cannula was occluded and the pulmonary artery pressure was incrementally increased by elevation of the reservoir. The Kf was calculated as the slope of the line relating the weight gain rate and pulmonary capillary pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Hemodilution reduces early reperfusion injury in an ex vivo rabbit lung preservation model.

We sought to reduce early ischemia-reperfusion injury after lung preservation by an initial brief period of hemodilute reperfusion. Left lungs of New Zealand White rabbits were ventilated with room air and reperfused in an ex vivo ventilation-perfusion apparatus after 18 hours of storage at 10 degrees C. Lungs were randomly assigned to one of three groups (n = 6) according to the composition of initial reperfusate. In group 1 (control), preserved lungs were reperfused with whole blood for 20 minutes (hematocrit, 38%). In the experimental groups, blood was diluted to a hematocrit of 10% with Ringer's lactate (group 2) or low-potassium-dextran solution (group 3) for the first 10 minutes of reperfusion, followed immediately by whole blood for 10 minutes. Oxygen tension of left ventricular effluent at the end of the 20-minute assessment period was significantly higher in both hemodiluted groups (mean +/- standard error of the mean: group 2, 81.3 +/- 6.6 mmHg; group 3, 77.0 +/- 9.5 mmHg, versus Group 1, 46.3 +/- 7.4 mmHg; p < 0.006). Similarly, mean tracheal airway pressure was reduced in the hemodiluted groups, suggesting improved compliance (group 2; 3.1 +/- 0.3 mmHg; group 3, 2.8 +/- 0.6 mmHg; versus group 1, 6.5 +/- 1.4 mm Hg; p < 0.05). An initial 10-minute period of hemodilute reperfusion appears to reduce early pulmonary ischemia-reperfusion injury in this 18-hour ex vivo rabbit lung preservation model.

Airway Resistance↗
PubMed1994

Administration of prostaglandin E1 after lung transplantation improves early graft function.

Early graft dysfunction continues to be a major clinical problem after lung transplantation. The objective of this experiment was to determine whether continuous administration of prostaglandin E1 (PGE1) after lung transplantation has a beneficial effect on early graft function. Left lung allotransplantation was performed in 10 size-matched mongrel dogs (weight, 24.4 to 31.4 kg). Lung preservation consisted of a bolus injection of PGE1 (250 micrograms) into the pulmonary artery, followed by a pulmonary artery flush with 50 mL/kg of 4 degrees C modified Euro-Collins solution. The lungs were then stored at 1 degree C for 12 hours. Left lung transplantation was performed using standard technique. The right pulmonary artery and right bronchus were ligated prior to chest closure. Animals were placed in the supine position and ventilated for 6 hours with 100% oxygen at a rate of 20 breaths/min, a tidal volume of 550 mL, and a positive end-expiratory pressure of 5 cm H2O. Animals were randomly allocated to one of two groups. Group I animals (n = 6) received continuous PGE1 infusion from the onset of implantation. The dose was gradually increased and fixed when mean systemic pressure showed a 10% decrease (mean PGE1 dose, 31.7 +/- 6.9 ng.kg-1.min-1). Group II animals (n = 4) received no PGE1. After the 6-hour assessment period, arterial oxygen tension and alveolar-arterial oxygen pressure difference were preserved in group I compared with group II (group I versus group II: arterial oxygen tension, 255.8 +/- 37.6 mm Hg versus 64.7 +/- 7.9 mm Hg [p < 0.05]; alveolar-arterial oxygen pressure difference, 411.1 +/- 70.5 mm Hg versus 597.5 +/- 1.3 mm Hg [p < 0.05]).(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗
PubMed1994

Pentoxifylline reduces lung allograft reperfusion injury.

Early graft dysfunction remains a significant problem in clinical lung transplantation. Pentoxifylline, a methylxanthine derivative, has been shown to have various beneficial effects on neutrophil-induced lung injury. We investigated effects of pentoxifylline on early posttransplantation lung function in a canine allograft model. Ten dogs underwent left lung allotransplantation. Donor lungs were flushed with modified Euro-Collins solution (50 mL/kg) and stored in an inflated state for 18 hours at 1 degrees C. In five experiments (group I), pentoxifylline was added to the flush and storage solutions (200 mg/L) at the time of harvest. The recipient animals received pentoxifylline (20 mg/kg intravenously) before reperfusion followed by pentoxifylline (0.1 mg.kg-1.min-1 intravenously) during the 6-hour posttransplantation assessment period. In group II, donors and recipients received no pentoxifylline. To evaluate only allograft function, the right main pulmonary artery and bronchus were ligated immediately after implantation. For 6 hours thereafter hemodynamics and gas exchange were assessed at 15-minute intervals while the animal was ventilated at an inspired oxygen fraction of 1.0. After 1 hour of assessment there was a significant difference in gas exchange between the groups, which persisted until the end of the study. By the end of the 6-hour assessment, the mean arterial oxygen tension was 236.7 mm Hg for group I versus 101.1 mm Hg for group II (p < 0.01), and the alveolar-arterial oxygen difference was 443.1 mm Hg versus 562.2 mm Hg (p < 0.015). Hemodynamics were not different between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Predictors, frequency, and indications for cardiopulmonary bypass during lung transplantation in adults.

The records for 162 lung transplantations performed in 158 patients were reviewed with regard to the predictors for, frequency of, and indications for using cardiopulmonary bypass during the procedure. There were a total of 8 en bloc double-lung transplantations, 83 single-lung transplantations, and 71 bilateral single-lung transplantations. Bypass was used electively for all double en bloc and three of the bilateral sequential lung transplantation procedures and for 26 unilateral lung replacement procedures in patients with pulmonary hypertension. Of the remaining patients, 1 single-lung transplant recipient required bypass for correction of a surgical mishap and 18 bilateral single-lung recipients required bypass during replacement of the second lung. No preoperative predictors for the need of bypass could be identified. Among the bilateral sequential lung recipients, the use of bypass did not seem to adversely affect outcome, as expressed in terms of the time until extubation, the time spent in the intensive care unit, and the time required to reach a room air oxygen tension greater than 60 mm Hg.

Adult↗
PubMed1994

Respiratory responses to CO2 rebreathing in lung transplant recipients.

To evaluate the respiratory responses after lung transplantation, we studied the hypercarbic ventilatory response in 20 patients with severe obstructive pulmonary disease and compared it with that of 10 normal subjects. Eleven patients underwent bilateral lung transplantation and 9 patients had single-lung transplantation. All patients had preoperative hypercapnia (51.3 +/- 9.7 mm Hg) and blunted slopes of CO2 rebreathing curves for minute ventilation (0.39 +/- 0.20 L.min-1.mm Hg-1) and inspiratory occlusion pressure (0.35 +/- 0.30 s-1). The hypercapnia and blunted ventilatory responses persisted at the initial postoperative test (5.8 +/- 2.0 days) despite improved pulmonary function (preoperative forced expiratory volume in 1 second [FEV1], 0.57 +/- 0.16 L; initial postoperative FEV1, 1.83 +/- 0.65 L; p < 0.001). By the 15th to 30th postoperative day (21.3 +/- 6.0 days), compared with preoperative and initial postoperative values, end-tidal CO2 had normalized (40.6 +/- 6.9 versus 51.3 +/- 9.7 and 49.6 +/- 10.3 mm Hg; p < 0.005) and was coupled with enhanced ventilatory responses for the rebreathing curve for minute ventilation (1.26 +/- 0.7 versus 0.39 +/- 0.20 and 0.32 +/- 0.32 L.min-1.mm Hg-1; p < 0.005) and the inspiratory occlusion pressure curve (0.98 +/- 7.4 versus 0.35 +/- 0.30 and 0.41 +/- 0.29 s-1; p < 0.005). These respiratory responses developed without a change in postoperative pulmonary function (initial postoperative FEV1, 1.83 +/- 0.65 L versus last postoperative FEV1, 1.96 +/- 0.66 L; p = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Tidal volume and respiratory rate changes during CO2 rebreathing after lung transplantation.

To evaluate the contribution of the respiratory pattern to the ventilatory response after lung transplantation, we studied the changes in minute ventilation, tidal volume, and respiratory rate during CO2 rebreathing in 14 patients with severe obstructive pulmonary disease, and compared them with 10 normal subjects. Seven patients underwent a bilateral lung transplantation and 7 patients had single-lung transplantation. Single-lung transplant recipients increased their respiratory rate by the last postoperative test compared with either preoperative or initial test periods (0.38 +/- 0.13 versus 0.027 +/- 0.24 or 0.12 +/- 0.08 breaths.min-1.mm Hg-1; p < 0.005). Bilateral lung transplant recipients showed a diminished ability to augment their respiratory rate by the last postoperative test compared with either preoperative or initial test periods (0.13 +/- 0.23 versus 0.54 +/- 0.25 or 0.25 +/- 0.29 breaths.min-1.mm Hg-1; p < 0.06). The restored ventilatory response by the fourth postoperative week was due to a statistically significant increase in tidal volume for both single and bilateral lung transplant recipients. This study demonstrates that when lung transplant recipients have an appropriate ventilatory response to CO2 rebreathing, single-lung transplant recipients have a respiratory pattern similar to normal; whereas the bilateral lung transplant recipients show the effects of total pulmonary denervation. We conclude that the preserved ventilatory response in lung transplant recipients is composed of a respiratory pattern that is influenced by the presence or absence of vagal inputs.

Adult↗
PubMed1994

Differences in early results after single-lung transplantation. Washington University Lung Transplant Group.

Single-lung transplantation is an effective treatment for end-stage pulmonary failure caused by a variety of lung diseases. Although single-lung recipients may undergo a similar operative procedure, physiologic differences in the remaining native lung dictate differences in postoperative management and perhaps outcome. To examine these effects on the early results after single-lung transplantation, we retrospectively reviewed the course of 83 patients undergoing single-lung transplantation from September 1988 through July 1993. The cause of the lung disease was obstructive (OLD) in 43, idiopathic pulmonary fibrosis (IPF) in 16, and primary pulmonary hypertension (PPH) in 24 patients. The hospital mortality was 5% in OLD, 13% in IPF, and 8% in PPH. Gas exchange as demonstrated by alveolar-arterial oxygen gradients was worse after transplantation in patients with IPF (349 +/- 159 mm Hg) or PPH (270 +/- 171 mm Hg) compared with patients with OLD (174 +/- 105 mm Hg; p < 0.05). Mean pulmonary artery pressures were higher in patients with IPF (28 +/- 6 mm Hg) and PPH (26 +/- 7 mm Hg) compared with patients with OLD (22 +/- 5 mm Hg; p < 0.05). Peak airway pressures after transplantation were greater in patients with IPF (36 +/- 6 cm H2O) compared with patients with OLD (28 +/- 6 cm H2O; p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗