Variaciones de la función respiratoria con la diabetes y/o con la edad / Changes of respiratory function with diabetes and/or with the aging process

Las alteraciones de la microcirculación pulmonar y los posibles cambios en elparénquima llevan a algunos autores a considerar el pulmón como un «órganodiana» más en la diabetes. Los estudios que valoran la repercusión de la hiperglucemiacrónica sobre la espirometría han encontrado cambios en lasmedidas transversales y en los seguimientos longitudinales de la capacidadvital forzada y del volumen espiratorio forzado en el primer segundo. Pero algunosdefectos de método, el hecho de que los valores se encontraran dentrode los límites de la normalidad y su falta de repercusión clínica cuestionan larelevancia actual de estos hallazgos(AU)

Alterations in the pulmonary microcirculation and the possible changes in theparenchyma lead certain authors to consider the lung as yet another “targetorgan” in diabetes. Studies assessing the effects of chronic hyperglycemia onthe spirometry have found changes in the cross-sectional measurements andlongitudinal follow-up of the forced vital capacity and the forced expiratoryvolume in the first second. However, certain flaws in the method, the fact thatthe values fell within the limits of normality and their lack of clinical repercussions,question the continuing relevance of these findings(AU)

Disnea de esfuerzo, deterioro del patrón ventilatorio y mala tolerancia al ejercicio: ¿ signos precoces de insuficiencia respiratoria? / Exertional dyspnea, rapid shallow breathing and poor exercise toleran Early signs of respiratory impairment?

IntroducciónLa disnea de esfuerzo (DE) es frecuente entre fumadores a pesar de una espirometría normal.ObjetivosDeterminar si el test de ejercicio y la observación de posibles alteraciones del patrón ventilatorio pueden reflejar una insuficiencia respiratoria precoz.Material y métodoSe ha comparado a 24 varones fumadores que presentaban DE con 31 varones fumadores sin DE. En ambos grupos se realizó espirometría, pletismografía, estudio del patrón ventilatorio, gasometría arterial y test de ejercicio incremental (30W/3min), empezando por 40W×10min. La se evaluó mediante la escala de Borg.ResultadosLa espirometría era normal en ambos grupos. Los sujetos con DE presentaron un aumento de la frecuencia respiratoria (fB) y un volumen corriente (VT) significativamente reducido (p<0,001), con un patrón respiratorio más superficial. Además, mostraban una reducción superior al 30% del consumo máximo del VÿO2pico y de la potencia máxima tolerada (Wmáx) (p<0,01). Se observó una disminución de la ventilación alveolar (VÿA/VÿE), la PaO2 y el pulso de O2 (p<0,01), mientras que la ventilación (VÿE), la relación ventilación (VE)/ventilación máxima minuto (MVV), el espacio muerto (VD), la lactatemia (AL) y la frecuencia cardiaca (FC) fueron, para un mismo nivel de ejercicio, significativamente mayores (p<0,01) en el grupo de disneicos.ConclusionesSujetos aparentemente sanos, cuya espirografía es normal, presentan DE, junto con una combinacion de efectos adversos durante el ejercicio (aumento de la demanda ventilatoria central, importantes alteraciones del patrón ventilatorio, con hipoventilación e importante reducción de la máxima cantidad de ejercicio). Tales alteraciones frecuentemente no se exploran, pero se podrían corregir mediante un elaborado tratamiento fisioterapéutico y entrenamiento muscular(AU)

AbstractExertional dyspnea (ED) is common among smokers despite a normal spirometry.ObjectivesThis study aimed to determine whether exercise testing, overbreathing and altered breathing pattern can reflect early respiratory impairment.Material and methodTwenty-four active ED male smokers aged 33–60 years, with no background of muscular, cardiac or respiratory disease, were compared to 31 healthy smokers (with no ED). Spirometry, plethysmography, ventilatory pattern and arterial blood gases were assessed in both groups and dyspnea was estimated using a Borg scale at every 30W/3min step of incremental maximal exercise, starting with 40W for 10min.ResultsSpirometry data was normal in both groups. Compared to healthy subjects, the respiratory pattern was significantly (p<0.001) more rapid and shallow with smaller tidal volume (VT) (p<0.001) and less alveolar ventilation (VÿA/VÿE) and PaO2 while ventilation (VÿE), the ratio VÿE/MVV, ventilatory frequency (fB), dead space ventilation (VD), lactic acidemia, and cardiac frequency (fC) were significantly higher (p<0.01) in the ED group. The significant differences (p<0.05) observed at rest were amplified during exercise and VÿO2 pico and maximal power load were 30% lower (p<0.001) in ED subjects.ConclusionsApparently healthy subjects, whose spirometry are normal, complain of exertional dyspnea associated with a combination of adverse effects of: increased central ventilatory demand, overbreathing, impairments of ventilatory pattern, hypoventilation, and severe reduction of the maximal levels of exercise. These changes are not often explored, although they are potentially susceptible to correction corrected with sophisticated respiratory physiotherapy and exercise training(AU)

[Respiratory muscle aids during an episode of aspiration in a patient with Duchenne muscular dystrophy]. / Ayudas a los músculos respiratorios durante un episodio de aspiración en un enfermo con distrofia muscular de Duchenne.

We report the case of a Duchenne muscular dystrophy patient with good bulbar function but severely decreased forced vital capacity (9%) and spontaneous peak cough flow (PCF) (2.35 L/s). The patient needed continuous noninvasive ventilation (NIV) consisting of a volumetric ventilator with a nighttime nasal mask and a daytime mouthpiece. He also required application of manually assisted coughing techniques by insufflation with a resuscitation bag and chest thrust (manually assisted PCF after maximum insufflation capacity of 4.33 L/s). An episode of serious food aspiration was resolved by his main caregiver through NIV and manually assisted coughing. Bronchoscopy under sedation using NIV with a lip seal connection to his volumetric ventilator later revealed that no material remained. This case exemplifies the potential role of skilled respiratory management in some neuromuscular diseases.

Ayudas a los músculos respiratoris durante un episodio de aspiración en un enfermo con distrofia muscular de Duchenne / Respiratory muscle aids during an episode of aspiration in a patient with Duchenne muscular dystrophy

Presentamos el caso de un enfermo afectado de distrofia muscular de Duchenne con buena función bulbar, pero con disminución importante de la capacidad vital forzada (9%) y del pico de flujo de tos espontáneo (2,35 l/s) que le obligaba a mantener ventilación no invasiva (VNI) continua (ventilador volumétrico, mascarilla nasal nocturna y pieza bucal en vigilia) y a utilizar ayudas manuales para la tos mediante insuflaciones con ambú y compresión torácica espiratoria (pico de flujo de tos asistida tras máxima capacidad de insuflación de 4,33 l/s). El paciente presentó una aspiración importante de material digestivo que se resolvió gracias a la asociación de las ayudas manuales para la tos proporcionadas por su cuidadora principal y a la VNI. En un segundo momento, la VNI con una boquilla sellada como conexión a un ventilador volumétrico permitió realizar una broncoscopia bajo sedación, en la que se comprobó que no había material retenido. Este caso es un ejemplo de la utilidad potencial del manejo cualificado de los problemas respiratorios en algunas enfermedades neuromusculares

We report the case of a Duchenne muscular dystrophy patient with good bulbar function but severely decreased forced vital capacity (9%) and spontaneous peak cough flow (PCF) (2.35 L/s). The patient needed continuous noninvasive ventilation (NIV) consisting of a volumetric ventilator with a nighttime nasal mask and a daytime mouthpiece. He also required application of manually assisted coughing techniques by insufflation with a resuscitation bag and chest thrust (manually assisted PCF after maximum insufflation capacity of 4.33 L/s). An episode of serious food aspiration was resolved by his main caregiver through NIV and manually assisted coughing. Bronchoscopy under sedation using NIV with a lip seal connection to his volumetric ventilator later revealed that no material remained. This case exemplifies the potential role of skilled respiratory management in some neuromuscular diseases

[Risk factors of readmission in acute exacerbation of moderate-to-severe chronic obstructive pulmonary disease]. / Factores predictivos de reingreso hospitalario en la agudización de la EPOC moderada-grave.

OBJECTIVES: More effective management of chronic obstructive pulmonary disease (COPD) and improved survival of COPD patients requires a better understanding of the risk factors for exacerbation. The aim of this study was to identify factors related to readmission in patients with moderate-to-severe COPD. PATIENTS AND METHODS: Ninety patients with moderate-to-severe COPD hospitalized consecutively for acute exacerbation were studied prospectively. At discharge, the following potential predictors were assessed: clinical and spirometric variables, arterial blood gases, and respiratory muscle strength determined noninvasively. The patients were followed for a period of 3 months. Readmission for exacerbation and time intervals free of hospitalization were recorded. RESULTS: Univariate analysis showed that the presence of cor pulmonale (P<.05), long-term oxygen therapy (P<.05), hypercapnia (P<.05), and high inspiratory load--mean inspiratory airway pressure measured at the mouth exceeding 0.40 cm H2O and a pressure-time index greater than 0.25 (P<.05 for both variables)--increased the risk of hospitalization for exacerbation. Multivariate analysis showed that only cor pulmonale (P<.05) and a high pressure-time index (>0.25, P<.05) were independently related to risk of readmission. CONCLUSIONS: Cor pulmonale and a high pressure-time index are independent risk factors for hospitalization for exacerbation of moderate-to-severe COPD.

Tos y enfermedades neuromusculares. Manejo no invasivo de las secreciones respiratorias / Cough and neuromuscular diseases. Noninvasive airway secretion management

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A simple noninvasive pressure-time index at the mouth to measure respiratory load during acute exacerbation of COPD A comparison with normal volunteers.

We assessed the validity of the pressure-time index (PTI) measured at the mouth as a noninvasive and simplified alternative to conventional tension-time index for assessing respiratory load and inspiratory muscle force reserve. PTI was measured within 48 h of hospital admission and at 24 h before discharge in 37 consecutive patients with acute exacerbation of chronic obstructive pulmonary disease (COPD) using the equation PTI = (P(awo)/MIP)(T(I)/T(T)) 100, where P(awo) is the mean airway pressure measured at the mouth, MIP the maximal inspiratory pressure, and T(I)/T(T) the inspiratory time (T(I)) to total cycle length (T(T)) ratio. Controls were 30 normal volunteers with similar anthropometric features. Mean (+/- SD) PTI values were significantly higher in COPD patients (0.29 +/- 0.10) than in controls (0.11 +/- 0.04) (P < 0.001) primarily because MIP and T(I)/T(T) were significantly lower and P(awo) was higher in the COPD population than in controls. As a result of improvement of the respiratory condition, PTI values were significantly lower at discharge (0.20 +/- 0.10 vs. 0.29 +/- 0.10, P < 0.001) due to a drop in P(awo) and an increase in MIP. The accuracy of different PTI cutpoints was assessed by comparison of the receiver operating characteristics curves. Best cutpoint values for differentiating COPD patients on admission and at hospital discharge from controls were 0.13 (positive predictive value 76%) and 0.17 (positive predictive value 92%) respectively. Noninvasive PTI measured at the mouth provides a valid and easy method for assessing respiratory muscle load and reserve. Changes in PTI values reflect functional improvement following treatment of acute exacerbation of COPD.

Non-invasive management of an acute chest infection for a patient with ALS.

We describe a man diagnosed with non-bulbar amyotrophic lateral sclerosis (ALS) who uses 24-h non-invasive ventilator at home, and assisted cough through the use of the mechanical insufflation-exsufflation (MAC) device (CoughAssist, J.H. Emerson). This was essential for the removal of bronchial secretions in order to provide successful non-invasive management (and indeed less suffering for the patient) during an acute respiratory tract infection with hypoxemia and failure of manually assisted cough.

Endurance training in patients with chronic obstructive pulmonary disease: a comparison of high versus moderate intensity.

PURPOSE: To create a maximum tolerated 45-minute aerobic training program for patients with chronic obstructive pulmonary disease (COPD) and to compare its outcomes with those of commonly prescribed moderate exercise. DESIGN: Prospective, randomized trial. SETTING: A work physiology laboratory. PATIENTS AND METHODS: The maximum exercise intensities that 7 COPD patients could sustain for 45 minutes were determined on a bilevel exercise ergometer. The patients then exercised 45 minutes daily, 5 days a week for 6 weeks, working 2.03+/-0.4 kJ/kg per session. They were matched with 6 COPD patients who pushed an O2 cart for 45 minutes daily, 5 days a week for 6 weeks, working 1.44+/-.35 kJ/kg per session. RESULTS: A 45 minute maximal regimen was established by alternating 1-minute peak exercise at peak VO2-levels with 4 minutes at the ventilatory anaerobic threshold or at 40% of peak VO2. Maximal bilevel training significantly decreased dyspnea at rest (p< or =.01) and the blood lactate level during submaximal exercise (p<.001), and increased peak VO2 and total physical work (p<.01), maximum inspiratory and expiratory pressures (p<.01), and grip and forearm strength and endurance (p<.01). The training also increased maximum voluntary ventilation while decreasing the ventilatory equivalent during exercise (p<.001). The O2 cart pushers significantly improved only on the 12-minute walk (p<.05). CONCLUSIONS: A maximally intense anaerobic exercise program can be created for most COPD patients that can significantly improve both skeletal and respiratory muscle strength and endurance as well as dyspnea and physiologic parameters.

Exercise causes blood glutathione oxidation in chronic obstructive pulmonary disease: prevention by O2 therapy.

The aim of the present study was to determine whether glutathione oxidation occurs in chronic obstructive pulmonary disease (COPD) patients who perform exercise and whether this could be prevented. Blood glutathione red-ox ratio [oxidized-to-reduced glutathione (GSSG/ GSH)] was significantly increased when patients performed exercise for a short period of time until exhaustion. Their resting blood GSSG/GSH was 0.039 +/- 0.008 (SD) (n = 5), whereas after exercise it increased to 0.085 +/- 0.019, P < 0.01. Glutathione oxidation associated with exercise was partially prevented by oxygen therapy (resting value: 0.037 +/- 0.014, n = 5; after exercise: 0.047 +/- 0.016, n = 5, P < 0.01). We conclude that light exercise causes an oxidation of glutathione in COPD patients, which can be partially prevented by oxygen therapy.

Noninvasive nasal mask ventilation beyond the ICU for an exacerbation of chronic respiratory insufficiency.

STUDY OBJECTIVE: To assess the usefulness of noninvasive nasal mask ventilation (NMV) in the treatment of an exacerbation of chronic respiratory insufficiency in patients stable enough to be admitted to a non-ICU ward. DESIGN: A prospective study in which the beneficial effect of NMV was compared with conservative treatment. SETTING: A ward of respiratory medicine of a tertiary-referral teaching hospital. PATIENTS: The study group included 15 patients with acute respiratory acidosis. These patients had pH less than 7.35 and PaCO2 more than 60 mm Hg, respiratory rate of 30 breaths or less per minute, hemodynamic stability, and alertness and willingness of cooperation with the NMV treatment. The control group consisted of 16 patients who fulfilled the same arterial blood gas requirements, retrospectively selected from the discharge forms of the ward of respiratory medicine for the year 1993. INTERVENTIONS: Patients underwent NMV for two sessions per day (one in the morning and one in the afternoon), each session lasting 4 h. A volumetric respirator (Monnal D; Taema; Paris, France) was used in four patients with restrictive disease. A positive-pressure ventilator (DP90; Taema; Paris, France) was used in 11 patients with obstructive disease. Control patients received standard medical, oxygen, and chest physical therapy. RESULTS: As compared with pre-NMV values, mean pH was significantly higher at 4 h of NMV after the patient's ventilatory adaptation (t = 8.814, p < 0.001) and at the end of NMV (t = 12.06, p < 0.001). Ventilatory support also produced a significant improvement in hypercapnia (pre-NMV vs NMV after the patient's ventilatory adaptation, t = 6.675, p < 0.001; pre-NMV vs post-NMV, t = 6.976, p < 0.001). Posttreatment pH and PaCO2 values were significantly higher and lower, respectively, in NMV-treated patients than in controls. At the end of treatment, a significantly higher PaO2/FIO2 ratio was documented in the study group than in controls (post-NMV vs posttreatment, t = 2.846, p < 0.01). CONCLUSIONS: NMV associated with standard treatment may be more beneficial than conservative treatment alone for improving blood gas exchange in patients with chronic respiratory insufficiency admitted to the hospital (but not the ICU) for an episode of acute decompensation and respiratory acidosis.

[Assisted ventilation via nasal mask in patients hospitalized in a pneumology ward for decompensation of their chronic air-flow obstruction]. / Ventilación asistida vía máscara nasal en pacientes hospitalizados en una sala de neumología por descompensación de su obstrucción crónica al flujo aéreo.

Our aim was to evaluate the efficacy of assisted ventilation through a nasal mask (AVN) in treating chronic obstructive pulmonary disease (COPD) patients who were admitted to a pneumology ward due to decompensation, with PaCO2 > 60 mmHg and pH < 7.35. We studied 13 COPD patients who were first observed for 1-2 days until adaptation and then given 2 daily sessions of AVN lasting 4 hours with double positive pressure (DP90) devices through Sullivan mask with a cannula for hyperoxia. Gasometric readings were recorded, along with subjective assessment of condition and problems with the mask. Gasometric readings were taken as follows: the first upon admission to the ward (AW), the second with AVN 2 days after adaptation and the third 3 hours after the second (POST). Statistical analysis was with a Student t-test for paired series. Mean age was 64 +/- 3 years and FEV1 was 0.69 +/- 0.14 l. Interruptions were due to the need for mouth opening even at minimum pressures, and the inability to adapt to the consequent tachypnea. No other problems were reported by the remaining patients and all perceived improvement subjectively. The pH of 7.29 +/- 0.03 at AW increased to 7.41 +/- 0.03 with AVN (p < 0.001) and held steady at 7.39 +/- 0.01 at POST (p < 0.001 POST-AW and p = NS POST-AVN). PaO2/FiO2 was 223 +/- 49 mmHg at AW and 267 +/- 41 mmHg at the POST reading (p = 0.06). PaO2 with AVN was 67 +/- 8 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)

Modifications of tissular oxygenation and systemic hemodynamics after the correction of hypocapnia induced by mechanical ventilation.

The modifications of systemic hemodynamics, oxygen transport and tissular oxygenation in mechanically-ventilated critical ARF (acute respiratory failure) patients, after the correction of its hypocapnia by addition of dead space (VD) are determined. The prospective and randomized study was carried out in a multidisciplinary ICU. Fifteen ARF patients were studied within the first 48 hours of evolution. All the patients were intubated and mechanically ventilated. Three stages were delimited: I) 30 min after the beginning of anesthesia; II) 30 min after adding 30 cm of VD; III) 30 min after replacing the previous VD with a VD of 60 cm. Similar steady states had been reached when the measurements were taken. Ventilation parameters and FiO2 were kept stable. In stage I the patients presented a pure respiratory alkalosis and, with respect to hemodynamics, a hyperdynamic situation. In stage II the acid-base balance was normalized with a continuation of the hyperdynamic situation and an increase in mixed venous oxygen tension and saturation (PvO2 and SvO2) (p < 0.001). Stage III was characterized by a pure hypercapnic acidosis and an increase in capillary wedge pressure (CWP) (p < 0.05), right atrial pressure (RAP) (p < 0.001) and cardiac output (Qt) (p < 0.001); simultaneously, the systemic vascular resistances (SVR) decreased (p < 0.01), the PvO2, SvO2 and oxygen delivery (DO2) increased (p < 0.001); oxygen utilization coefficient (OUC) decreased (p < 0.01). The results suggest that the variations in PvO2 and SvO2 are a direct consequence of the modifications in blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Implications of lower- and upper-limb training procedures in patients with chronic airway obstruction.

In assessing the effectiveness of lower-limb and upper-limb nonspecific physical training, we have considered 3 objectives in this study: (1) determination of clinical and functional actual state in patients with chronic airway obstruction (CAO), before and after training; (2) determination of the tests, level of work, and duration of the session training as well as how to increase the training load throughout the training program; and (3) the "particular" upper-limb exercise training in patients with CAO. Many personal factors such as psychologic (personality, degree of patient motivation), alcohol and smoking habits, physical activity, malnutrition, as well as routine tests, at rest and maximal exercise, including the control of metabolic acidosis (lactate) and arterial blood gases (or at least of SaO2), should be considered. Exercise training has the potential to improve exercise tolerance in those who develop metabolic acidosis. The pattern of lactates during exercise represents a good criterion on the selection of patient's training. Two ergospirometric strategies, at high intensity exercise, established from the anaerobic threshold (AT) are described: (a) the above AT 45 min constant exercise (high work rate), at 60% of the difference between AT and maximum VO2 or 80% of the maximal tolerated power (MTP), and (b) the "45 min square-wave endurance exercise test" (SWEET), simulating an interval training session, established from the MTP and the AT. To the SWEET's base (% MTP from AT or aerobic training), a peak of 60 s at MTP (anaerobic training) is added every 5 min. While those 2 protocols, after 6 to 8 weeks of training, lactate and ventilation were lower for identical work rate. In addition, endurance (time in "a" and total physical work in "b") increased up to 60%. Further, maximal exercise ventilation and maximum VO2 increased after SWEET training. Roughly every 7 training sessions, a 10% to 15% reduction in heart rate (HR), during the training program, allows the patient to increase the work rate of the sessions. Evaluation of training the upper limb in patients with CAO requires measurements of MTP and maximum VO2. With the upper limb (wheelchair ergometer), Wmax, maximum VO2, and HR represent 30%, 65%, and 95%, respectively, of the lower limb (ergometer). Further, some expiratory and inspiratory accessory muscles show electromyographic fatigue at the MTP upper-limb level. This may contribute to the rationale for training respiratory muscles.(ABSTRACT TRUNCATED AT 400 WORDS)