The incidence of nosocomial infections in a pneumology division and intermediate intensive care unit.

It has been shown that the problem of nosocomial infections is different in each specialist hospital division, and it is important to be aware of the local situation and to identify the specific problems. In order to set up an effective prevention programme and in the setting of a general system of control of nosocomial infection, we studied the incidence of infections and correlated the pathogenic organisms appearing during hospitalization in patients admitted to our Pneumology Division and Intermediate Intensive Care Unit over a period of 12 months. A nosocomial infections incidence of 13% was observed and 75% of these were respiratory, 21% urinary and 4% other infections. Seventy two percent of pathogenic agents were Gram-negative bacilli and 28% Gram-positive cocci. The site-specific rates of infections observed are related to intrinsic (host dependent) and extrinsic (non-host-dependent) risk factors that have not been exhaustively evaluated in the present study. However, the data so far collected will allow us to redirect the resources used in the control of nosocomial infections by targeting efforts at the surveillance of better defined groups of patients and by achieving data more suitable for comparisons between hospitals.

Effect of pressure and timing of contraction on human rib cage muscle fatigue.

Breathing against inspiratory loads can be accomplished with different degrees of coupling between the diaphragm and the other muscles attached to the rib cage (RCM). Thus, the electromyographic signs of fatigue develop separately in each muscle group. While breathing with diaphragm emphasis, the occurrence of diaphragmatic fatigue was found to be related to the tension-time index TTdi (= Pdi/Pdimax x Ti/Ttot). Above the critical range of 0.15 to 0.18, the endurance of the diaphragm is less than 1 h and it is inversely related to the TTdi value. However, in most loaded breathing conditions, the spontaneous pattern of breathing is characterized by predominant activation of RCM. The tension-time conditions at which fatigue develops during breathing with RCM emphasis are not known. We assessed the critical tension-time value in four normal subjects breathing with RCM emphasis against inspiratory threshold loads. RCM predominance was achieved by developing negative abdominal pressure swings during inspiration, and it was characterized by the tension-time index TTrc (Ppl/Pplmax x Tl/Ttot), where Ppl is pleural pressure developed under this condition. Above a critical TTrc value of 0.30, endurance time was inversely related to TTrc, and it resulted from failure of the RCM rather than of the diaphragm. We conclude that the critical threshold, as assessed by TTrc, is higher for breathing patterns with RCM emphasis than previously described by TTdi for diaphragm emphasis. However, when predominantly recruited, as in breathing patterns commonly adopted in loaded conditions, the RCM fatigue earlier than the diaphragm.

Relationship between the perception of breathlessness and inspiratory resistive loading: report on a clinical trial.

We investigated the relationship between the sensation of breathlessness and progressively higher resistive inspiratory loadings in nine normal subjects (31 +/- 17 yr; forced expiratory volume in one second (FEV1) = 105 +/- 9% of predicted) and in eighteen chronic obstructive pulmonary disease (COPD) patients (63 +/- 7 yr; FEV1 = 43 +/- 17% of predicted). The sensation of breathlessness correlated with mouth pressure both in normals (r = 0.94) and in COPD patients (r = 0.95), with a steeper slope in patients. On this basis we studied the effect of inspiratory muscle training on the sensation of breathlessness in sixteen COPD patients (63 +/- 8 yr; FEV1 = 52 +/- 19% of predicted). After a baseline assessment of lung function, MIP (maximal inspiratory pressure), inspiratory muscle endurance and the sensation of breathlessness (Borg scale) at different inspiratory loads, the patients were divided into two groups: the first was trained by means of resistive breathing, the second used a placebo device. At the end of the training, MIP increased more in the trained group (56 +/- 10 to 69 +/- 15 cmH2O; p less than 0.001) than in the placebo group (50 +/- 17 to 56 +/- 22 cmH2O; p = NS). The Borg score fell significantly at all the considered inspiratory loads in trained patients, but not in the placebo group. We conclude that the training with inspiratory resistances decreased the sensation of breathlessness via an increase in inspiratory muscle strength and endurance.

Increased neutrophil chemotactic activity in exercise- and "fog"-induced asthma.

To investigate whether exercise- and ultrasonic "fog"-induced asthma are due to the same mechanism, i.e. mediator release induced by osmotic changes, we measured the serum neutrophil chemotactic activity before and after exercise and inhalation of "fog" in 15 asthmatic subjects. To assess changes in airway caliber we measured specific airway conductance (SGaw); to assess changes in neutrophil chemotactic activity we measured the maximum distance reached by neutrophils in a filter when challenged with the subject's serum in a Boyden chamber. In 10 subjects, SGaw decreased by more than 35% and neutrophil chemotactic activity increased significantly (P less than 0.05) both after exercise and "fog", whereas in five subjects no change occurred either after exercise or "fog". We conclude that both exercise- and "fog"-induced asthma are associated with increased serum neutrophil chemotactic activity, and that both stimuli may cause asthma by osmotically triggering mediator release from mast cells.

Broxaterol: a double-blind clinical trial comparing broxaterol and salbutamol.

10 patients with reversible bronchospasm received by the oral route in a double-blind fashion broxaterol, Z. 1170, 0.250 and 0.500 mg in comparison with salbutamol 4 mg as base and a placebo. Measurements of FEV1, heart rate and arterial pressure were performed before and 0.5, 1, 2, 4, 6 h after each treatment. Z. 1170 was followed by increases in FEV1 over the baseline and the placebo values that were significant up to the 4th hour with the 0.500 mg dose, up to the 2nd hour with the 0.250 mg dose. The difference between the effects of the two dose levels of Z. 1170 was significant, and the effect of the 0.500 mg dose was not significantly different from that of salbutamol 4 mg. The maximum increments in FEV1 following Z. 1170 averaged 15.8% for the 0.250 mg dose, 24.3% for 0.500 mg dose, and they were recorded at the 2nd hour. At this time point the mean increment in FEV1 following salbutamol was 18.0%. The maximum increments in FEV1 with salbutamol averaged 18.7% and were recorded at the 1st hour. At this time the mean increments for Z. 1170 0.250 and 0.500 mg were 13.8 and 20.0%, respectively. Heart rate and arterial pressure did not show any changes of clinical significance.