ABSTRACTS 223

dry lung weight, and fractional albumin uptake when com- pared with that in control rats mechanically ventilated at 7 cmH,O peak inspiratory pressure. These changes suggest that edema may be due at least in part to alterations in microvascular permeability. Moderate peribronchovascular edema was present. At the ultrastructural level, some endo- thelial cells were found detached from their basement mem- brane. This lesion has been previously described in other types of pulmonary microvascular injury. The above findings remained almost unchanged after 10 min of HIPPV. After 20 min of HIPPV, we observed the outpouring of a high protein content alveolar flooding accompanied by a further signifi- cant increase in fractional albumin uptake and dry lung weight. Additional anatomic damage appeared including epithelial lesions and hyaline membranes. Thus, HIPPV edema presents all the features of high permeability edema. These results may be of concern in the ventilatory manage- ment of patients with acute respiratory failure in order to avoid additional damages induced by local overinflation. (Reprinted with permission.)

lnspiratory Muscle Training in Patients With Chronic Obstructive Pulmonary Disease. Chen H, Dukes R, Martin BJ. Am Rev Respir Dis 131:251, 1985.

To investigate the effects of inspiratory muscle resistive loading training (IMT) on exercise performance in chronic obstructive pulmonary disease (COPD), 13 patients undergo- ing standard pulmonary rehabilitation were divided into control (n = 6) and experimental (n = 7) groups. Prior to training, we measured inspiratory muscle strength and endurance, resting pulmonary function, and exercise perfor- mance on a bicycle ergometer (a progressive test and an endurance test at two thirds of maximal work load). We then determined their resistive loads for training by measuring their IO-min maximal sustainable resistance. Training by patients in the experimental group involved inspiring against a predetermined resistive load. The control subjects breathed through a sham training tube, so that studies were performed in double-blind fashion. The training consisted of 15-min sessions twice daily for 4 wk. The IMT dramatically improved inspiratory muscle endurance-represented as either sustainable inspiratory pressure (SIP) or endurance time at 60% of maximal inspiratory mouth pressure (PIMmax) at functional residual capacity. The SIP of the trained group increased from 29 i 11 to 46 f 11% of PIMmax (p < 0.005). Training slightly increased inspiratory muscle strength (p < 0.05), as determined by PIMmax. In contrast, resting pulmonary function and performance of both progressive and constant-load exercise remained unchanged. We conclude that 4-wk IMT in a pulmonary rehabilitation setting improves inspiratory muscle endurance in patients with COPD without changing pulmonary function or exercise performance. (Reprinted with permission.)

Effect of Hypophosphatemia on Diaphragmatic Contractility in Patients With Acute Respiratory Failure. Aubier M, Murciano D, Lecocguic Y, et al. N Engl J Med 313:420, 1985.

We studied the effects of hypophosphatemia on diaphrag- matic function in eight patients with acute respiratory failure who were artificially ventilated. Their mean serum phospho-

rus level was 0.55 k 0.18 mmol per liter (normal value, 1.20 f 0.10). The contractile properties of the diaphragm

were assessed by measuring the transdiaphragmatic pressure generated at functional residual capacity during bilateral supramaximal electrical stimulation of the phrenic nerves. Diaphragmatic function was evaluated in each patient before and after correction of hypophosphatemia, which was achieved by administration of 10 mmol of phosphorus (as KH,PO,) as a continuous infusion for four hours. After phosphate infusion, the mean serum phosphorus level increased significantly (1.33 + 0.21 mmol per liter, P < 0.0001). The increase in serum phosphorus was accompanied by a marked increase in the transdiaphragmatic pressure after phrenic stimulation (17.25 + 6.5 cm H,O as cornpared with 9.75 f 3.8 before phosphate infusion, P < 0.001). Changes in the serum phosphorus level and transdiaphrag- matic pressure were well correlated (r = 0.73).

These results strongly suggest that hypophosphatemia impairs the contractile properties of the diaphragm during acute respiratory failure, and they emphasize the importance of maintaining normal serum inorganic phosphate levels in such patients. (Reprinted with permission.)

A Comparison of Atropine Sulfate and Metaproterenol

Sulfate in the Emergency Treatment of Asthma. Karpel JP, Appel D, Breidbart D, et al. Am Rev Respir Dis 1331727, 1986.

Twenty-one patients presenting to an emergency room with moderate to severe asthma were entered into the follow- ing double-blind, crossover study. First, patients inhaled twice at 30-min intervals either atropine sulfate (AS) (3.2 mg and 3.2 mg; total dose, 6.4 mg) or metaproterenol sulfate (MP) (15 mg and 15 mg; total dose, 30 mg). Then after 80 min (crossover), they inhaled either AS (3.2 mg) or NIP (15 mg). FEV, was measured before treatment and at 30,40,70, 80, 110, and 120 min after the start of the study. FEV, from 20 patients who completed the protocol were compared (Student’s paired t test), and the values are presented as mean + SEM. Both groups began with equally severe airways obstruction (AS versus MP: 1.02 r 0.07 L and 0.92 t 0.15 L, respectively; p > 0.05). After 120 min, when all had received both medications, FEV, had improved significantly and similarly among both groups, indicating that initially they had equivalent bronchodilator capacities. Atropine sulfate produced small but significant changes in FEV, at 30 and 70 min, but not at 80 min nor after crossover. In contrast, MP both alone and after crossover significantly improved FEVt. The difference in improvement among the groups was signifi- cant at 80 min and after crossover. Atropine sulfate produced multiple adverse effects in all patients. We conclude that during acute severe asthma, AS (6.4 mg) does not produce clinically significant bronchodilation either alone or in com- bination with MP. (Reprinted with permission.)

A Comparison of the Bronchodilating Effects of a &eta-Z Adrenergic Agent (Albuterol) and an Anticholinergic Agent (lpratopium Bromide), Given by Aerosol Alone or in Sequence. Easton PA, Jadue C, Dhingra S, et al. N Engl J Med 315:735, 1986.

We evaluated the effect of anticholinergic and beta- adrenergic inhaled bronchodilators, alone or in sequence, in