Although all three of our patients eventually died, it is difficult to assess whether or not their survival was shortened by BCBR. On direct questioning they stated that their improved comfort justified the possibility of decreased longevity from the operation. Depression of ventilation and worsening of blood gases clearly occurred in all. Although one might expect that such derangements of blood gases would affect functional capacity and survival, there is a remarkable dearth of information about the complications of BCBR. Vermeire et al had no immediate mortality among 27 patients with severe COPD undergoing BCBR for relief of dyspnea, and felt that the five-year mortality rate of 37 percent observed in their subjects was in keeping with the severity of their underlying disease. Despite the fear of inducing obstructive sleep apnea by BCBR, Vermeire et al found no evidence of it during sleep studies in four patients after the surgery. …Read the rest of this article
The postoperative decrease in Vo2 and Vco2 during exercise probably reflects in part decreased work of breathing due to reduction in ventilation, as the patients were doing the same amount of external work. However, we cannot exclude the possibility that at least part of the decrease in Vo2 and Vco2 was related to a more efficient walking stride learned as part of the rehabilitation program.
The mechanisms by which BCBR might relieve dyspnea include reduction in hypoxic bronchocon-striction, reduction in ventilation and removal of sensory signals to the respiratory center. Although hypoxic bronchoconstriction has been demonstrated in animals, it has not been shown to be important in humans with asthma, and our patients showed no improvement in maximal expiratory flow. The importance of respiratory effort in the development of the symptom of dyspnea has been eloquently described in the work of Campbell, Killian and coworkers. this
…Read the rest of this article
Dyspnea may be an incapacitating symptom in patients with COPD. Efforts to relieve it with standard modalities such as bronchodilators, corticosteroids, oxygen, physical retraining, respiratory muscle training, nutrition and even psychoactive drugs are frequently inadequate. Bilateral carotid body resection is an intriguing but unproven and potentially dangerous procedure for the relief of this symptom in patients with advanced lung disease.
We had the unplanned opportunity to evaluate pre-and postoperatively three patients who chose independently to undergo therapeutic removal of their carotid bodies. All three of these patients reported substantial immediate and sustained relief of dyspnea during walking and other activities of daily living following BCBR. This decrease in the sensation of dyspnea with activity was associated with and possibly due in part to substantial reductions in ventilation (Table 1, Fig 2) and occurred despite remarkable worsening of blood gases (Table 1). read only
…Read the rest of this article
All three patients had severe airflow limitation and hyperinflation which was not affected by the surgery (Fig 1). The moderate preoperative resting and exercise hypercapnea and hypoxemia deteriorated markedly postoperatively, though there was no change in the alveolar-arterial oxygen difference or pH (Table 1). Ventilation fell postoperatively both at rest ( — 25 percent) and during exercise (— 39 percent) (Table 1, Fig 2). The striking reduction in Ve during postoperative exercise was due mainly to a decrease in respiratory frequency ( — 28 percent) and was associated with decreased oxygen consumption ( — 26 percent) and carbon dioxide production (— 22 percent) (Table 1). Mean inspiratory flow (tidal volume/time of inspiration = Vt/Ti) and ventilatory equivalents for 02 and C02 fell during exercise postoperatively (Table 1), presumably as a reflection of postoperative decrease in respiratory drive. At the completion of exercise, all patients reported that they were less dyspneic and the exercise protocol was less difficult than it had been preoperatively. …Read the rest of this article
We studied three men who were 57, 67 and 69 years old at the time of initial presentation to our rehabilitation program. They had severe COPD (FEV, <0.75 L) related historically to cigarette smoking, and when first seen, could walk only short distances (<200 m) at slow paces (0.8-1.2 mph). All of them were on therapeutic regimens consisting of inhaled bronchodilators, oral theophylline, oral prednisone (10-20 mg/day), and supplemental oxygen via nasal cannulae (12-18 hours per day). The six-week outpatient rehabilitation program included walking endurance training, arm exercises, breathing exercises, relaxation and energy conservation training. …Read the rest of this article
Physiologic and Clinical Observations in Three Patients
Dyspnea is the major limiting symptom of the chronic obstructive pulmonary diseases (COPD). While treatment with bronchodilators, corticosteroids, and antibiotics can improve symptoms and pulmonary function in some patients with COPD, dyspnea remains a severe symptom for many despite pulmonary rehabilitation with physical training, oxygen supplementation, inspiratory muscle strengthening, theophylline, psychological interventions and drugs which alter respiratory drive or central perception (eg, sedatives or narcotics’). …Read the rest of this article