Reduction pneumonoplasty for patients with a forced expiratory volume in 1 second of 500 milliliters or less.

BACKGROUND: Patients with severely impaired pulmonary function are considered at high risk for emphysema operations. We prospectively evaluated 44 patients with a forced expiratory volume in 1 second of 0.5 L or less undergoing reduction pneumonoplasty for dyspnea uncontrolled by medical management (confirmed by Borg and modified Medical Research Council dyspnea scales). METHODS: There were 28 men and 16 women (mean age, 66 years) with a mean preoperative forced expiratory volume in 1 second of 0.41 L (range, 0.23 L to 0.50 L). Preoperative therapy consisted of bronchodilators (100% of patients), oxygen (80%), and steroids (72%). Hypercarbia was seen in 80% of patients, and 66% had pulmonary hypertension. Unilateral reduction pneumonoplasty by a video-assisted thoracic surgical approach was performed in 34 patients, 6 patients underwent bilateral reduction pneumonoplasty by a video-assisted thoracic surgical approach, and 4 patients underwent bilateral reduction pneumonoplasty by a video-assisted thoracic surgical approach, and 4 patients underwent bilateral reduction pneumonoplasty by median sternotomy. Discrete emphysematous regions were resected using staplers with buttressing, and regions of homogeneous emphysema were plicated with KTP or neodymium:yttrium-aluminum garnet laser radiation. RESULTS: There was one death within 30 days, two additional deaths within 60 days, and five additional deaths within 1 year. Hospital stay averaged 12 days. Intensive care unit stay averaged 4 days. Subjective improvement was noted by 89%. Borg and modified dyspnea scores improved from 7.6 to 4.5 (p < 0.01) and from 3.9 to 2.35 (p < 0.01), respectively. Forced expiratory volume in 1 second was 0.62 L at 1 year, a 51% improvement (p < 0.001). Forced vital capacity was 1.32 L preoperatively and 2.05 L at 1 year (a 56% improvement) (p < 0.001). CONCLUSIONS: This experience documents that patients with severely impaired lung function can successfully undergo operation for emphysema. To obtain these results one must tailor the operative approach to the patient's disease.

Effect of exercise on mouth-to-cecum transit in trained athletes: a case against the role of runners' abdominal bouncing.

The role of exercise on the gastrointestinal motor function and in particular on transit time is a matter of hard debate. Numerous studies in the past have failed to demonstrate a consistent effect of short term exercise on transit time in untrained subjects and trained athletes. It has been, however, suggested that running, with its constant jostling of the abdomen, may have a different effect than exercise performed in a stationary setting. To examine the effect of running on gastrointestinal transit time, 8 healthy male trained runners ingested a lactulose meal and assigned to rest or exercise on separate days. Exercise consisted of running 9.6 km in an hour, while exhaled gas was sampled every 10 minutes for volume, minute ventilation and hydrogen concentration. The mean O2 consumption was 36.8 ml/min/kg during exercise session and 4.7 ml/min/kg during rest period. Post lactulose rise in hydrogen concentration occurred at a mean of 85 +/- 25.1 and 84 +/- 18.1 minutes for resting and exercise sessions respectively (p = 0.732). On the basis of the present data we conclude that (1) mouth-to-cecum transit time is not affected by short term intense exercise in trained athletes; (2) that bouncing of the abdominal content in case of running probably does not change the transit time; and finally, (3) the impact of moderate to intense short term exercise on the mouth-to-cecum transit is not influenced by the subject's fitness state.

Video-thoracic surgery for treatment of end-stage bullous emphysema and chronic obstructive pulmonary disease.

Surgical treatment of emphysema and chronic obstructive pulmonary disease (COPD) has received renewed attention because of advances in instrumentation and techniques. Our approach includes video-assisted thoracotomy, neodymium-Yag and KTP laser plication of emphysematous bullae, pulmonary resection using reinforced stapling, and pleurodesis: reduction pneumonoplasty. In a 9-month period, 28 patients (age 52 to 78, 23 men and 5 women) with end-stage disease underwent reduction pneumonoplasty. Oxygen therapy was required in 82 per cent, steroid therapy was used in 86 per cent, and the preoperative FEV1 averaged 0.68 +/- 0.05. The most severely diseased lung was determined by physical, chest film, and CT scan, and this lung had reduction pneumonoplasty. There were no hospital mortalities. Prolonged postoperative air leaks occurred in 42 per cent of patients. Postoperatively FEV1 was 0.91 +/- 0.35. Lung size (chest film) showed 21.6 per cent reduction in volume. Subjective improvement was noted in 78.6 per cent (22/28) of patients, and no patient reported worse symptoms. Half of the steroid-using patients required a reduced steroid dose or no steroid therapy, and 5/23 (21.7%) patients had reduced oxygen requirements. Reduction pneumonoplasty can improve the symptoms of severe emphysema and COPD. Our results with treatment of one lung suggest that further improvement may be anticipated by proceeding with surgery for the contralateral lung.

Thoracoscopic laser ablation of pulmonary bullae. Radiographic selection and treatment response.

The purpose of this study was to develop objective preoperative selection methods for predicting outcome in patients undergoing thoracoscopic laser ablation of emphysematous pulmonary bullae. Initial radiographic presentation was correlated with physiologic function both before and after the operation in 24 patients entered into a prospective clinical protocol for evaluation of carbon dioxide laser treatment of emphysematous pulmonary bullae. Nineteen surviving patients underwent follow-up evaluation 1 to 3 months after the operation. Pulmonary function test results showed improvements in spirometry (forced vital capacity increased 0.82 +/- 0.125 L, forced expiratory volume in 1 second increased 0.36 +/- 0.07 L, and maximum voluntary ventilation increased 11.69 +/- 2.6 L/m; p < 0.002); airway resistance decreased by 0.9 +/- 0.35 cm of water/L per second, and specific conductance increased 0.019 +/- 0.006 L/cm H2O per second (p < 0.02). Lung volumes improved (residual volume decreased 1.25 +/- 0.23 L, p < 0.001) without significant change in resting gas exchange. Quantitative radiographic grading of extent of preoperative pulmonary bullae correlated well with response to laser treatment in patients with preoperative and postoperative studies. Patients with large bullae accompanied by crowding of adjacent lung structures, upper lobe predominance, and minimal underlying emphysema had greatest improvement in pulmonary function results with laser bullae ablation (p < 0.05). However, some patients with multiple smaller bullae and diffuse emphysema also demonstrated objective improvement after operation. Quantitative radiographic analysis of the extent of bullous disease and the degree of associated emphysema can be used to determine short-term postoperative pulmonary response and may be useful in selecting future thoracoscopic laser bullae ablation candidates. Additional follow-up will be necessary to further improve selection criteria and help define the long-term role of thoracoscopic laser treatment of bullous emphysema.

Melatonin and gonadotropin secretion after acute exercise in physically active males.

Serum concentrations of luteinizing hormone (LH), follicle stimulating hormone, testosterone (T) and melatonin were measured in seven physically active male volunteers after exercise on a treadmill using the Bruce protocol. Measurements were made on blood samples obtained before exercise, within 30 s after exercise, at 15 min after exercise, and subsequently at 30-min intervals after exercise for a total duration of 180 min. Serum LH concentration fell from a peak post-exercise level of 15.7 (4.7) IU.l-1 [mean (SD)] to a nadir of 10.3 (2.4) IU.l-1 (P < 0.004). Nadir values in individual volunteers were seen between 60 and 150 min after exercise. This fall in serum LH was paralleled by a similar fall in the concentration of serum T. Serum melatonin concentrations did not change significantly after exercise. It is concluded that melatonin, despite is reported anti-gonadotropic properties, does not play a role in the depression of serum LH after acute strenuous exercise in physically active males.

Tidal breath flow-volume curves in obstructive sleep apnea.

Because of the gravitational position during sleep and the associated relaxed state, we hypothesized that passive expiration in the supine position might reflect upper airway pathophysiology in obstructive sleep apnea (OSA). We prospectively enrolled and tested 92 subjects with several clinical conditions. Maximal comfort and relaxation during expiration was achieved by connecting subjects to a ventilator via a mouthpiece. An initial respiratory rate of 16 breaths/min and tidal volume of 10 ml/kg were selected. Fine adjustments were then made to achieve maximal subject relaxation. Using this method, we obtained reproducible tidal breath flow-volume curves (TBFVC). Testing was performed in both sitting and supine positions. Standard pulmonary function tests, including spirometry and lung volume measurements, were also obtained in both sitting and supine positions. Of 86 patients who could be evaluated, 12 (60%) of 20 subjects with documented OSA (respiratory disturbance index: mean, 64.8; range, 10 to 120.5) demonstrated a positional change in the terminal portion of the TBFVC; 10 (32%) of 31 with a history of snoring also tested positive, but only three (9%) of 35 subjects with no OSA, by polysomnography (n = 8) or questionnaire (n = 27), demonstrated such a positional change. This positional change in TBFVC, which was significantly more frequent in subjects with OSA, could not be attributed to any measurable pulmonary function abnormality or body mass index. We believe this positional change in TBFVC reflects upper airway functional narrowing induced by assumption of supine position and decreasing airflow rates.

Inhibin and gonadotrophin secretion in physically active males after acute exercise.

Serum concentrations of luteinizing hormone (LH) follicle stimulating hormone (FSH), testosterone and inhibin were measured in six physically active male volunteers after heavy exercise on a treadmill. Hormone measurements were made before exercise, immediately after exercise and at 30-min intervals for 3 h after exercise. Serum concentrations of LH fell after exercise reaching nadir values between 60 and 180 min post-exercise. The nadir value of LH for the group as a whole occurred 90 min after exercise. Serum testosterone concentrations paralleled the changes in LH concentrations. Serum FSH and inhibin concentrations did not show any appreciable change from baseline values. The data suggest that acute exercise does not significantly lower serum concentrations of FSH or inhibin. Whether repetitive and prolonged heavy exercise, as in competitive runners, produces alterations in serum inhibin concentrations remains to be determined.

Thoracoscopic carbon dioxide laser treatment of bullous emphysema.

A new technique of thoracoscopic laser ablation of pulmonary bullae suitable for patients with multiple bullae and diffuse emphysema was developed and assessed in 22 patients. 20 of 22 patients survived. Pre-operative and postoperative functional evaluation is available for the 11 patients followed up for more than a month; at 1 to 3 months postoperatively there were increases in FVC (mean 2.0 litres pre-operatively to 2.7 litres postoperatively, p less than 0.001), in FEV1 (0.74 to 1.06 litres, p = 0.01), and in maximum exercise treadmill times (5.4 min to 8.0 min, p less than 0.01). Postoperative air leaks lasted a mean of 13 days and usually resolved spontaneously. Other complications were bleeding (1 patient) and unilateral acute lung injury (1 patient). These results suggest that selected patients with diffuse emphysema and pulmonary bullae may benefit from thoracoscopic carbon dioxide laser ablation.

Concentrations of volume-regulatory hormones after acute exercise in physically conditioned males.

Plasma renin activity and plasma concentrations of atrial natriuretic peptide (ANP), arginine vasopressin (AVP) and aldosterone (Aldo) were determined in six physically conditioned male volunteers and five unconditioned volunteers who served as controls. All volunteers were subjected to acute exercise for 15 min or until exhaustion. In the conditioned volunteers, the plasma concentrations of all hormones did not change when compared with pre-exercise values measured immediately after and 60 min after exercise. Similarly, plasma renin activity (PRA) after exercise was unchanged when compared with pre-exercise levels. In contrast, the unconditioned volunteers showed elevation of the plasma concentrations of AVP, and Aldo. PRA also increased in the unconditioned volunteers, but plasma ANP concentrations were not significantly different from base-line pre-exercise levels. These data suggest a decrease in central volume with exercise in the unconditioned individuals, which probably does not occur in the conditioned individual because of adaptive mechanisms. The data also suggest that in the physically conditioned individual, significant atrial distention with resultant release of atrial natriuretic peptide does not occur, or alternatively, that significant atrial distention in these subjects fails to produce the expected release of atrial natriuretic peptide. In the unconditioned individual, the postulated decrease in effective central volume following exercise would not be expected to trigger any rise in ANP.

Corticotropin releasing hormone and gonadotropin secretion in physically active males after acute exercise.

Plasma concentrations of corticotropin releasing hormone (CRH) and the serum concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone, adrenocorticotropic hormone (ACTH) and cortisol were measured in seven physically active males after acute exercise on a treadmill using the Bruce protocol. Measurements were made in the basal pre-exercise state, immediately after exercise, and at 30-min intervals for 3 h after exercise. Serum LH concentrations declined following exercise reaching nadir values between 60 and 180 min after exercise (90 min post exercise in the group). The nadir values in individual volunteers were significantly lower than both the baseline and post-exercise levels. This fall in serum LH concentration appeared to follow a slight but significant elevation of the plasma concentration of CRH which reached peak levels when measured immediately post exercise. Plasma ACTH concentrations paralleled the rise in CRH, but fell to undetectable levels of below 13.8 nmol.l-1 (less than 5 ng.l-1) 60 min after exercise. Plasma cortisol concentrations peaked approximately 30 min after the rise in ACTH, after which they gradually declined to baseline levels. Plasma testosterone concentrations paralleled the concentrations of LH. The data suggest that CRH, on the basis of its previously described gonadotropin-depressant property, may be the hormone involved in the exercise-mediated decline in serum LH. Alternatively, some as yet unidentified factor(s), may be involved in producing the altered concentrations of both LH and CRH.

Beta-endorphin/beta-lipotropin release and gonadotropin secretion after acute exercise in physically conditioned males.

beta-endorphin (beta-EP) and beta-lipotropin (beta-LPH) concentrations were measured in the basal state and after acute exercise for 15 min or until exhaustion in 6 physically conditioned male volunteers. Serum concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone and prolactin were also measured in the basal state. In addition, the concentrations of the gonadotropins (LH and FSH) were determined after exercise and the gonadotropin response to gonadotropin releasing hormone was assessed before and after exercise. The data show that acute exercise stimulates the release of both beta-EP and beta-LPH which return to base-line levels within 60 min after exercise. This is in contrast to our previously described results in physically unconditioned male volunteers in whom only beta-LPH release was noted after exercise. Serum LH concentrations declined after exercise reaching nadir values between 60 to 150 min after exercise. As we previously reported in physically unconditioned male volunteers, serum FSH concentrations did not change with exercise and the gonadotropin response to LRH stimulation was uninfluenced by exercise. Serum testosterone and prolactin concentration were within the normal range for healthy adult males. We speculate that the difference in beta-EP release with exercise in physically conditioned and unconditioned males represents a difference in processing of the opioid precursor molecule (pro-opiomelanocortin, POMC) in the two groups.

Mechanisms of expiratory valves resistance.

Expiratory valves are the major source of resistance in ventilator circuits. Some valves, particularly under certain conditions, cause high resistances. To establish the mechanisms of expiratory valve resistance (R), we measured R of 4 commercial valves under several experimental conditions. The pressure above the diaphragm of one of the valves was also measured. The results reveal that all valves produce significant resistance to air outflow. This resistance is the result of the physical and functional interplay of several valve components. (1) In most valves, the dimensions of the air pathway through the valve contribute minimally to resistance in spite of its tortuosity. (2) The diaphragm adds a major contribution to valve resistance particularly at low flows. The diaphragm effect has 2 components: its weight--a gravity-dependent, fixed effect most predominant at very low flows and evident in all the valves--and a spring-like effect--a component related to the resistance of the diaphragm to deformation and of variable magnitude in different valves. Because of diaphragm-related components at low flows, valves behave as variable threshold resistors. (3) There is limitation to air egress from above the diaphragm at higher exhaled flows, which further contributes to valve resistance. The first and last components cause the valves to function also as flow resistors. Constant flows effectively counteract the diaphragm spring-like effect. Measuring valve resistance during constant flow underestimates the resistance that occurs under dynamic flow conditions characteristic of clinical situations.