[Respiratory response to inspiratory resistive load changes in patients with obstructive sleep apnea syndrome]. / Odpowiedz oddechowa na zmiane oporu wdechowego u chorych na obturacyjny bezdech senny.

Patients with OSA have many episodes of increased airway resistance because of repeated collapses of upper airways during night. The aim of this work was to evaluate respiratory response during chemical stimulation without and with added inspiratory resistive load (10 cmH2O/L/sec). The studies were performed during quiet breathing with air and during hypercapnic and hypoxic rebreathing tests without and with inspiratory resistive loading in 23 obese (BMI = 34.4 +/- 4.3 kg/m2) patients with OSA and in 10 healthy subjects with similar weight (BMI = 32.4 +/- 4.3 kg/m2). The measurements of respiratory responses (ventilation, mouth occlusion pressure) were performed with the use of computerized equipment. During quiet breathing in response to added load an increase of P0.1 in controls and in OSA patients was observed. During hypercapnic stimulation the ventilatory response with additional load decreased in patients as well as in controls. The slope of mouth occlusion pressure response increased significantly in controls (from 4.40 to 6.83 cmH2O/kPa, p < 0.001) and slightly weaker in OSA patients (from 4.21 to 5.43 cmH2O/kPa, p < 0.05). Although the difference between the slopes was not significant, we found that the absolute increase of P0.1 measured at point 8 kPa of PEtCO2 during loaded breathing was significantly smaller in OSA patients in comparison to controls. (2.1 vs. 10.3 cm H2O; p < 0.001). During hypoxic stimulation occlusion pressure responses were similar in both examined groups. In conclusion we postulate that OSA patients have impaired respiratory compensation of additional inspiratory load, what was demonstrated during hypercapnic rebreathing test.

Respiratory responses to chemical stimulation in patients with obstructive sleep apnoea.

Chemical control of breathing in obstructive sleep apnoea (OSA) patients has been studied by many authors. The results of previous studies, especially those dealing with hypoxic drive, are discordant. Respiratory responses were studied during hypercapnic and hypoxic stimulation in a group of 37 normocapnic patients with OSA during wakefulness. The diagnosis of OSA was established by standard polysomnography. These patients had increased apnoea/hypopnoea index (AHI; 51 +/- 22 (mean +/- SD)), obesity (body mass index (BMI) 32.4 +/- 5.6 kg.m-2) and normal lung function tests. The control group consisted of 14 healthy obese subjects (BMI 31.2 +/- 3.3 kg.m-2). Respiratory responses (ventilatory and mouth occlusion pressure (P0.1)) during hypercapnic and hypoxic rebreathing tests were measured with the use of computerized equipment. Respiratory responses during hypercapnic stimulation were similar to those in the control group (change in (delta) minute ventilation (V'E)/delta carbon dioxide tension (PCO2) 23.5 +/- 14.8 versus 22.3 +/- 10.0 L.min-1.kPa-1, delta P0.1/delta PCO2 4.6 +/- 3.6 versus 4.2 +/- 2.6 cmH2O.kPa-1). During isocapnic hypoxic stimulation in OSA patients the mean ventilatory response was higher than in the control group (delta V'E/delta arterial oxygen saturation (Sa,O2) 2.6 +/- 1.7 versus 1.7 +/- 0.7 L.min-1.%-1) but this difference was not statistically significant. Nevertheless, it was found that 13 (35%) OSA patients had increased ventilatory responses. The mean P0.1 response in OSA patients was higher but did not differ significantly from those in the control group (delta P0.1/delta Sa,O2) 0.43 +/- 0.38 versus 0.35 +/- 0.12 cmH2O.%-1). The results demonstrated that respiratory responses to chemical stimulation in awake normocapnic patients with obstructive sleep apnoea were in the normal range, similar to those in control obese subjects. During hypoxic stimulation some of them had increased ventilatory (35%) and mouth occlusion pressure (16%) responses.

The susceptibility of gram-negative rods and their adaptive forms resistant to colistine to the bactericidal action of sera.

The susceptibility of Escherichia coli K1, Salmonella enteritidis, Salmonella typhimurium strains and their adaptative forms resistant to colistine (Colr forms) was compared with respect to their sensitivity to the bactericidal action of normal cord serum and normal bovine serum. It has been shown that the Colr forms are more susceptible to sera as compared to initial strains. The increase of sensitivity of the Colr forms is connected with structural changes within bacterial cell wall which is the target for complement as well as for colistine.

[Chemical control of breathing in patients with obstructive sleep apnea]. / Chemiczna regulacja oddychania u chorych na obturacyjny bezdech senny.

The authors have studied chemical control of breathing in 37 normocapnic patients with OSA. These patients had increased apnea-hypopnea index (AHI = 51 +/- 22), obesity (BMI = 32.4 +/- 5.6 kg/m2) and normal lung function tests. Control group consisted of 20 healthy subjects with normal weight (BMI = 23.1 +/- 2.4 kg/m2). Respiratory responses (ventilatory and P0.1) to hypercapnic and hypoxic stimulation during rebreathing tests were measured with computerized methods. The obtained results in OSA patients were compared with the data of the control group. The results exceeding mean values of the control group above 1.64 SD were recognized as hyperreactive responses. The majority e.g. 26 patients (OSA-N) had normal respiratory responses during hypercapnic stimulation. delta V/delta PCO2 = 16.8 +/- 4.5 L/min/kPa, P0.1/delta PCO2 = 3.5 +/- 2.4 cm H2O/kPa/. In remaining 11 patients (OSA-H) respiratory responses were significantly increased delta V/delta PCO2 = 39.1 +/- 18.8 L/min/kPa, P0.1/delta PCO2 = 8.6 +/- 3.9 cm H20/kPa). During isocapnic hypoxic stimulation majority e.g. 25 patients (OSA-H) had significantly increased respiratory responses delta V/delta SaO2 = 3.28 +/- 1.63 L/min/%, delta P0.1/delta SaO2 = 0.54 +/- 0.43 cm H2O/%/. In remaining 12 patients (OSA-N) respiratory responses were within normal limits delta V/SaO2 = 1.2 +/- 0.28 L/min/%, delta P0.1/ delta SaO2 = 0.21 +/- 0.07 cm H2O/%/. The above results indicated, that majority OSA patients (67.5%) had increased ventilatory and P0.1 responses to hypoxic stimulation. Among them also 11 patients had increased respiratory responses to hypercapnia. It seems, that increased respiratory responses to hypoxic stimulus in OSA patients are symptoms of protective reaction to hypoxaemia occurring during repetitive sleep apnoea and reveals increased neuro-muscular output.

[Pattern of breathing and obstruction pressure in patients with airway obstruction after inhalation of bronchodilators]. / Wzorzec oddychania i cisnienie okluzji u chorych z obturacja dróg oddechowych po inhalacji leku rozszerzajacego oskrzela.

The neuromuscular drive is increased in patients with an airway obstruction. The aim of the study was to estimate an influence of beta-agonist on breathing pattern and mouth occlusion pressure (P0.1) in patients with reversible and nonreversible airway obstruction. Ventilatory function tests, pattern of breathing analysis, mouth occlusion pressure (P0.1) and inspiratory impedance (P0.1/Vt/Ti) were measured in 23 obstructive patients and 20 healthy subjects. In all patients these measurements were repeated 20 minutes after bronchodilator inhalation (0.2 mg fenoterol). During quiet room-air breathing in patients we observed increased Vt, Vt/Ti comparing with healthy persons. The time of inspiration (Ti) and total time (Ttot) were shortened in comparison to our control group. P0.1 and inspiratory impedance were significantly increased (P0.1 3.6 +/- 1.6 vs 1.6 +/- 0.3 cm H2O, p < 0.01 and P0.1/Vt/Ti 6.6 +/- 2.3 vs 3.8 +/- 1.0 cm H2O/L/s). Measurements performed after bronchodilator inhalation revealed decrease of P0.1 and P0.1/Vt/ Ti in patients responsive to beta-agonist (delta FEVI > 15%). In unresponsive patients (delta FEVI < or = 15%) such decrease in neuromuscular respiratory drive was not observed. We conclude that diminishing of increased neuromuscular respiratory drive in patients with reversible obstruction is a consequence of airway resistance decreasing. It seems to be an additional, advantageous for a patient, effect of bronchodilator inhalation.

[Results of respiratory muscle training in patients with chronic obstructive lung diseases with a moderately severe course]. / Wyniki treningu miesni oddechowych u chorych na przewlekla obturacyjna chorob,e pluc o srednio ciezkim przebiegu.

The aim of the study was to testify the effectiveness and acceptance of combination of the resistive inspiratory muscle training and the following walking training in 26 stable COPD pts with FEVI%VC about 50%. Measurements of inspiratory (MIP cm H20) and expiratory (MEP cm H20) muscle strength and also spirometric examinations two times before the training and one time after every month of observation were done. During first 3 months of the training inspiratory resistor (Pflex) was used. Everyday 20 s MVV with smaller orifice of Pflex (strength training) and 30 min quiet breathing by medium orifice of Pflex 3 times a week (endurance training) were performed. In first 3 months of experiment 13 patients resigned of it. Other 13 pts (age 64 +/- 11.9. F-4 with medium FEVI%VC = 47.3 +/- 14.5, MIP = -54.1 +/- 11.4, MEP = = 99.8 +/- 40.5) were trained during 3 months. In 11 of them (FEVI%VC = 50.0 +/- 17.3) MIP improved by 33%. Values of other indices did not change at all. After 3 month of resistive training 11 pts (3-F) were qualified to walking training but only 5 (1-F) of them had finished it. After 5 month of exercises their MIP improved by 74% (p < 0.5) and MEP by 50% (p < 0.05). We conclude that our method of resistive breathing with Pflex is effective and well tolerated by stable COPD pts but accepted only by 50% of them. It may be used as the first step before conditioning training. Inspiratory muscle training is not alternative to pharmacological treatment but is valuable supplementation of it.

Formaldehyde exposure enhances inhalative allergic sensitization in the guinea pig.

Formaldehyde (FA), a common indoor air pollutant, has been associated with increased prevalence rates of asthmatic symptoms among exposed individuals in epidemiologic surveys. We studied the influence of FA exposure on inhalative allergic sensitization in the guinea pig. Three groups of guinea pigs (n = 12 each) were exposed to clean air or two different FA concentrations (0.13 and 0.25 ppm) over 5 consecutive days. Exposure was followed by inhalation of 0.5% ovalbumin (OA) as sensitizing allergen. Three weeks later, specific bronchial provocation with OA was performed with body plethysmographic measurement of compressed air (CA). Furthermore, specific anti-OA-IgGl (reaginic) antibodies were determined in serum. In a further six animals, the respiratory tract was examined histologically for signs of inflammation directly after the end of FA or clean air exposure. In the group exposed to 0.25 ppm FA, 10/12 animals were found to be sensitized to OA (positive reaction on specific provocation) vs. 3/12 animals in the control group (P < 0.01). Furthermore, CA measurements of specific bronchial provocation and serum anti-OA-antibodies were significantly higher in the 0.25 ppm FA group than in controls (CA 0.35 vs. 0.09 ml median, P < 0.01; anti-OA-IgGl 13 vs. < 10 EU median, P < 0.05), indicating enhanced sensitization. In the group exposed to 0.13 ppm FA, no significant difference was found compared to the control group. There was no sign of inflammation of the lower airways in FA-exposed guinea pigs other than mucosal edema, which was discovered by morphometry. We conclude that short-term exposure to a low concentration of FA (0.25 ppm) can significantly enhance sensitization to inhaled allergens in the guinea pig.

Control of breathing in obstructive sleep apnoea and in patients with the overlap syndrome.

In some patients obstructive sleep apnoea (OSA) may co-exist with chronic obstructive pulmonary disease (COPD) and respiratory failure; the so-called "overlap syndrome". Obstructive, hypercapnic patients have both blunted ventilatory and mouth occlusion pressure responses during CO2 stimulation. The purpose of this study was to compare the pattern of breathing and CO2 response between OSA patients and those with the overlap syndrome. Twenty obese men with OSA and normal lung function (Group A), 11 obese men with overlap syndrome (Group B) and 13 healthy nonobese subjects (Group C) were examined. Lung function tests, breathing pattern, mouth occlusion pressure (P0.2) at rest, and respiratory responses during CO2 rebreathing were investigated. Diagnosis of OSA was established by standard polysomnography. There were no statistical differences between Groups A and B in apnoea & hypopnoea index (62 vs 54), mean arterial oxygen saturation (SaO2) during sleep (85 vs 84%) and in body mass index (BMI) 34.3 vs 36.3 kg.m-2. Minute ventilation, mean inspiratory flow and P0.2 at rest were increased in both groups of patients in comparison to controls. During CO2 rebreathing, group A had normal ventilatory and P0.2 responses, similar to controls, (2.7 +/- 1.1 vs 2.1 +/- 0.4 l.min-1.mmHg-1 and 0.7 +/- 0.3 vs 0.71 +/- 0.25 cmH2O.mmHg-1, respectively). However, Group B had significantly decreased ventilatory and P0.2 responses to CO2 (0.71 +/- 0.23 l.min-1.mmHg-1 and 0.34 +/- 0.17 cmH2O.mmHg-1, respectively). This comparison showed that patients with OSA had normal CO2 response when awake, whereas those with overlap syndrome had diminished CO2 response when awake.(ABSTRACT TRUNCATED AT 250 WORDS)

[New computerized system for clinical evaluation of respiratory regulation]. / Nowy skomputeryzowany system pomiarowy do klinicznych badan regulacji oddychania.

The foundations for a computer program allowing to monitor "on line" physiological data to clinically evaluate ventilatory control were set up. The new equipment demonstrates important innovations--lowered flow resistance, and decreased dead space, modernization of the blocking steering the computer valve. The new program allowed to decrease the time for analysis from couple of minutes to seconds. The results of ventilatory control studies in 11 healthy volunteers were found in ranges of normal values calculated earlier using an analogue method and are similar to those from literature.

[Regulation of respiration in patients with sleep apnea syndrome]. / Regulacja oddychania u chorych na obturacyjny bezdech senny.

20 obese men with OSAS were examined. Polysomnography confirmed this diagnosis. In the daytime pattern of breathing, mouth occlusion pressure (P0.2) and ventilatory responses during CO2 rebreathing test were evaluated. Lung function indices were within normal limits except decreased value of MEF 25 and slight hypoxaemia (Pa0.2 -67 +/- 6 mm Hg). In comparison to control subjects the patients with OSAS when awake had increased ventilation, Vt/Ti ratio and P0.2. This suggests increased inspiratory neuromuscular output in daytime. During CO2 rebreathing test the whole ventilatory and P0.2 response lines were shifted to the left but the slopes of these lines were within normal limits. We conclude that the control of breathing in OSAS patients is changed in comparison to healthy subjects with normal weight.

[Control of respiration in patients with respiratory insufficiency in chronic obstructive lung disease]. / Kontrola oddychania u chorych z niewydolnoscia oddychania w przebiegu przewleklej obturacyjnej choroby pluc.

Twenty eight COPD patients with respiratory insufficiency were studied. These included: 12 hypoxemic and normocapnic patients, 16 hypoxemic and hypercapnic patients, and 22 healthy volunteers. During at rest respiration both COPD groups differed from the control group--demonstrating a higher respiratory incidence, VT/Ti and PO2 values. During hypercapnic stimulation using the rebreathing method the ventilatory response to CO2 in the COPD patients was lowered in comparison with the control. Increase of occlusion pressure as a response to the increasing hypercapnia was lowered in both groups, significantly in patients with hypercapnia.

[Control of breathing in patients with mechanical disorders of the lung]. / Kontrola oddychania u chorych z zaburzeniami mechaniki plucnej.

22 normal volunteers, 57 patients with obstructive changes and 34 with restrictive type changes were studied. The following parameters were analyzed: maximal inspiratory and expiratory pressures, occlusion pressure and components of the breathing pattern. The patients were divided according to the degree of airway resistance and fall of vital capacity. All patients compared with the healthy volunteers demonstrated higher minute ventilation, and a higher neuro-muscular respiratory drive as shown by the VT/Ti index and occlusion pressure. The breathing pattern did not correlate significantly with the different abnormalities of respiratory function in the studied groups. In the patients with obstructive changes a weak correlation was found between the occlusion pressure and airway resistance. In patients with restrictive type changes a weak correlation between occlusion pressure, static and specific compliance was found. The occlusion pressure was a more specific parameter characterizing respiratory drive compared with the VT/Ti index. Disturbances of pulmonary mechanics have a small but significant effect on respiratory control.

Changes in respiratory muscle function after neostigmine injection in patients with myasthenia gravis.

In sixteen patients with myasthenia gravis, the weakness of respiratory muscles, especially of expiratory, caused some disturbances in lung function. Thirty minutes after injection of neostigmine, general improvement of muscle function was accompanied by an increase of strength and endurance of respiratory muscles. The mean value of maximal inspiratory mouth pressure (PImax) increased by 33%, maximal expiratory mouth pressure (PEmax) by 23.5% and maximal voluntary ventilation (MVV) by 21%. As a consequence of these changes amelioration of lung function indices was found, vital capacity increasing on average by 13% and residual volume decreasing by 12.5%. We concluded that patients with generalized myasthenia gravis have disturbances in lung function which may be partially improved by neostigmine injection or other anticholinesterase agents.