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Biomedical subjects

T Barchfeld

Publications and source records attributed to T Barchfeld.

9 recordsLinked to original sources

[Difficult weaning].

Respiratory failure as a result of overload and/or reduced capacity of the respiratory muscles is the most common cause of unsuccessful weaning and the need for long term mechanical ventilation. Chronic obstructive pulmonary disease (COPD) is the most common underlying cause leading into long term mechanical ventilation. The most important clinical parameter for fatigue of the respiratory muscles is the rapid shallow breathing index. Other essential factors which impact weaning failure, are the underlying diseases (e. g. neuromuscular disease or heart failure), micro- and macro aspiration, malnutrition, anemia and obesity. A protocol based strategy to discontinue mechanical ventilation and the use of weaning predictors are helpful. Nonetheless the experienced physician is irreplacable in the weaning process. Reconditioning of the respiratory muscles is the main focus during weaning after long term mechanical ventilation and all therapeutic measures should be targeted to unload the fatiguing respiratory muscles. With the widely used assisted ventilation modes, the inspiratory work of breathing is still significantly increased. Only controlled mechanical ventilation (pressure- or volume controlled), which may also be applied to unsedated patients when individually adapted, offers the best possible relief and recovery of the respiratory muscles. Additional strategies, such as the balancing of anemia, reduction of the respiratory drive with i. e. morphine derivates, oxygen therapy during spontaneous-breathing trials and supine position for patients with obesity contribute to the recovery. Particularly patients with chronic lung diseases with hypercapnia benefit from the use of non invasive ventilation (NIV) after extubation to prevent postextubation failure and even after tracheostomy. However, NIV should only be applied under close monitoring and in cooperative patients, always considering the limits of the method. Dying under mechanical ventilation in the end stage illness is still a challenge for all involved persons. In the end stage of their disease for some patients it is possible to discontinue mechanical ventilation so they can spend the last period of their lives on a normal ward or even at home.

Humans↗

[Positive pressure ventilation in Cheyne-Stokes respiration].

Cheyne-Stokes respiration (CSR) is found in patients with chronic left ventricular failure and associated with a reduced prognosis. Continuous positive airway pressure (CPAP) improves the survival rate. In this retrospective study we report on the effect of different positive pressure ventilation modes in CSR. The observation period lasted from 1995 - 1999. Inclusion criteria was CSR with a respiratory disturbance index > 10/h whereas > 50 % of the events had to be central and/or mixed. In each patient a 4 week lasting intervention with each of CPAP, Bilevel CPAP in spontan mode (i.e. BiPAP S or BiPAP ST) and BiPAP in controlled mode (i.e. BiPAP T) was performed. Responder were defined by subjective and objective criteria. In total 41 males were included. Responder were distributed as follows: CPAP: n = 13 patients (31.7 %), BiPAP S/ST: n = 9 patients (22.0 %) and BiPAP T: n = 12 patients (29.3 %). In total 7 from 41 patients (17.1 %) rejected a long-term treatment with positive pressure ventilation. The majority of patients with CSR responded to CPAP and BiPAP S/ST mode. Compared to the other responder groups the best quality was reached with BiPAP T. However the latter was performed only by 29 % of the population.

Aged↗

Long term effects of non-invasive mechanical ventilation on pulmonary haemodynamics in patients with chronic respiratory failure.

BACKGROUND: It is not known whether long term nocturnal mechanical ventilation (NMV) reduces pulmonary hypertension in patients with chronic respiratory failure (CRF). METHODS: Pulmonary haemodynamics, spirometric values, and gas exchange were studied in 33 patients requiring NMV due to CRF (20 with thoracic restriction, 13 with chronic obstructive pulmonary disease (COPD)) at baseline and after 1 year of NMV given in the volume cycled mode. Patients with COPD also received supplemental oxygen. RESULTS: Long term NMV improved gas exchange while lung function remained unchanged. Mean pulmonary artery pressure at rest before NMV was higher in patients with thoracic restriction than in those with COPD (33 (10) mm Hg v 25 (6) mm Hg). After 1 year of NMV mean pulmonary artery pressure decreased in patients with thoracic restriction to 25 (6) mm Hg (mean change -8.5 mm Hg (95% CI -12.6 to -4.3), p<0.01) but did not change significantly in patients with COPD (mean change 2.2 mm Hg (95% CI -0.3 to 4.8)). CONCLUSIONS: Long term NMV in CRF improves pulmonary haemodynamics in patients with thoracic restriction but not in patients with COPD.

Chronic Disease↗

Scintigraphy for evaluating early aspiration after oral feeding in patients receiving prolonged ventilation via tracheostomy.

OBJECTIVE: In tracheotomised patients the incidence of aspiration is difficult to determine because investigators often apply different criteria. In this study a scintigraphic method was used to visualise feeding aspiration directly and the results were compared with clinical evidence of aspiration. DESIGN: Prospective study in difficult-to-wean patients with tracheostomy. SETTING: Respiratory ICU. PATIENTS AND METHODS: The study population consisted of 62 consecutive patients (16 females, age: 64.1+/-11.1 years). All patients were tracheotomised and had previously been long-term ventilated in other ICUs due to weaning failure. The scintigraphic test was performed during spontaneous breathing. The standard nutrition consisted of a liquid, semi-liquid and solid meal which was labelled with 100 MBq 99mTc-human serum albumin. MEASUREMENTS AND RESULTS: Scintigraphic aspiration (SA) was defined as positive if radioactivity was detected in the bronchial system using a scintillation camera. Furthermore, aspiration was proven clinically (CA). CA and SA yielded identical results in 54 of the 62 patients [10 positive (16%) and in 44 negative (71%)]. CA, but not SA, was seen in 4/62 (6.5%) and SA, but not CA, was found in 4/62 (6.5%) patients. CONCLUSIONS: Our data re-emphasise that aspiration in tracheotomised patients is common (in our study approximately 30%). The scintigraphic method failed to identify all tracheotomised patients with clinically significant aspiration; however, it did suggest that some patients had subclinical aspiration.

Aged↗

[Evaluation of daily activity in patients with COPD].

BACKGROUND: Recently we could show that the daily activity in patients with hypercapnic respiratory failure as judged by the total amount of movements per day increased by 120% after 3 months of non-invasive mechanical ventilation. This study was designed to evaluate the reproducibility of the result of a movement detector in measuring daily activity of patients with COPD. PATIENTS AND METHODS: 25 outpatients (11 females, 56 +/- 12 years old) with stable non-hypercapnic COPD (FEV1 = 47 +/- 9% predicted) were examined twice during a 7 days lasting interval, one month apart using a pedometer. RESULTS AND CONCLUSIONS: The repeatability of the activity counts in the non-hypercapnic COPD patients was high (1st study period: 3,781 +/- 2,320 movements/d, 2nd study period: 3,626 +/- 2,149 movements/d) and in these patients activity correlated significantly with FEV1 (r = 0.54, p = 0.006).

Activities of Daily Living↗

[Effect of intermittent ventilation on pulmonary hypertension in chronic respiratory failure].

Intermittent non-invasive (or nocturnal mechanical ventilation) eliminates symptoms of hypoventilation and improves gas exchange in patients with chronic respiratory failure. Performing right heart catheterisation we studied the influence of nocturnal mechanical ventilation on pulmonary hemodynamics. We investigated 20 patients with restrictive thoracic diseases (Post-TBC: n = 9, scoliosis: n = 11, PaCO2: 59.8 +/- 7.6 mmHg) and 13 patients with COPD (n = 13, PaCO2: 58.5 +/- 7.8 mmHg). All patients were mechanically ventilated in controlled mode. During the study the medication was not changed; COPD patients with long-term oxygen maintained this therapy. Right-heart catheterisation was performed immediately before and after 1 year nocturnal mechanical ventilation. In patients with thoracic restriction NMV induced a marked reduction of pulmonary artery pressure (PAP) from 33.2 +/- 10.0 mmHg before to 24.8 +/- 6.2 mmHg after 1 year nocturnal mechanical ventilation. In the COPD group PAP increased from 25.3 +/- 6.0 mmHg before to 27.5 +/- 6.0 mmHg after 1 year nocturnal mechanical ventilation. In contrast to the COPD group in patients with chronic respiratory failure due to thoracic restriction nocturnal mechanical ventilation causes substantial reduction in pulmonary artery pressure after a one year application.

Carbon Dioxide↗

[Value of various intra- and extraoral therapeutic procedures for treatment of obstructive sleep apnea and snoring].

BACKGROUND: Recently intra- and extraoral devices are increasingly used in order to treat obstructive sleep apnea (OSA) and snoring. We examined the value of some devices according to the literature and our own results. PATIENTS AND METHODS: The mandibular advancing devices aim at increasing upper airway diameter. The active part of the tongue extending device (SnorEx) is a stamp connected to a piston which exerts pressure at the base of the tongue causing its forward displacement; we studied 23 patients. The principle of an optically stimulating system ("eye-cover", Snore-Stop) consists of a microphone and light diods which are integrated in the eye-cover. After detecting acoustic signals (for example snoring) optical stimuli are generated in front of the eyes, which are thought to induce arousals causing a change of body position and the reduction of the snoring and apneas; we measured 24 patients. The principle of the tongue-retainer (Snore-Master) is the fixation of the tongue in a ventral position, which is thought to enlarge the mesopharyngeal area; we studied 14 patients. The nose plaster (Breathe-Right) contains an elastic spine that pulls the alae nasi cranial. This manipulation is thought to increase the diameter of the nostril and reduce the airway resistance. We measured 30 patients with obstructive sleep apnea and 20 snoring subjects without obstructive sleep apnea. RESULTS: Regarding the mandibular advancing due to different appliance designs and study protocols variable success rates have been documented. In patients with mild to moderate obstructive sleep apnea a reduction of the sleep related breathing disorder could be shown. Non compliance (NC) to the tongue extending device was 75% (17/23). Non-compliance-patients were characterized by unacceptable local-side-effects of the prosthesis, lacking improvement of symptoms and of the respiratory disturbance index. Both tongue-retainer and -extensor are characterized by a high incidence of local side effects. Neither the eye-cover nor the nose plaster could improve the severity of obstructive sleep apnoe or snoring. In contrast to another study we could not show a significant effect of the tongue-retainer. CONCLUSIONS: Neither the nose plaster nor the optical stimulating device influenced the degree of obstructive sleep apnea and snoring. There are conflicting data regarding the tongue retainer. The high rate of non-compliant subjects and the low efficacy of the tongue extending prosthesis precludes large-scale use of this treatment modality in patients with obstructive sleep apnoe and snoring. In selected individuals suffering from a mild to moderate degree of obstructive sleep apnea with CPAP-inefficiency and -incompliance the mandibular advancing principle may be an therapeutic alternative to CPAP.

Equipment Design↗

[Optical stimulation method (Snore-Stop) and tongue retainer (Snore-Master) without relevance in therapy of obstructive sleep apnea and snoring].

Recently intra- und extraoral devices are increasingly used in order to treat obstructive sleep apnea and snoring. We examined the value of an optically stimulating system ("eye-cover", Snore-Stop) and a tongue-retainer (Snore-Master) as treatment of the obstructive sleep apnoe or snoring. In case of the eye-cover is a microphone integrated, which detects acoustic signals (e.g. snoring). After detection of snoring optical stimuli are generated in front of the eyes. This is intended to induce an arousal of the patient, without awaking him, causing a change of body position and this reduces the snoring or apneas. For the examination of the eye-cover in 26 patients (23 men, 55.6 +/- 10.3 years) polygraphic studies were performed while sleeping one night with the eye-cover and one night without, respectively. Visual analogue scales (VAS) were used in order to measure quality of life and sleep and the adverse effects of the device. To examine the tongue-retainer 14 patients (13 men, aged 52.9 +/- 11.8 years) were measured polygraphically. Again the subjective scores were assessed using the VAS. The principle of the tongue-retainer is to create a hollow space in front of the teeth, in which the tongue is positioned. Fixation of the tongue in this ventral position is thought to enlarge the mesopharyngeal area in order to reduce the upper airway obstruction. For both devices the index of snoring, the apnea-hypopnea-index, the index of desaturation, the mean and minimal SaO2 and SaO2 < 90 % in % of the night did not change significantly. Furthermore the subjective perception of the patients concerning their quality of sleep and life did not change. Moreover, despite of an adequate adaptation-period the use of the tongue-retainer was associated with considerable adverse effects. Neither the eye-cover nor the tongue-retainer could improve the severity of obstructive sleep apnoe or snoring.

Adult↗

[Work of breathing in differentiation of various forms of sleep-related breathing disorders].

BACKGROUND: In contrast to the obstructive sleep apnoea syndrome (OSA) the obesity-hypoventilation syndrome (OHS) is characterised by persistent hypercapnia during the day and predominant hypoventilation during sleep. In this study we wanted to know whether work of breathing (WOB) in a sitting and supine position separates both groups. PATIENTS AND METHODS: OSA population: 20 men, 50.5 +/- 9.2 years, Body Mass Index (BMI: 54.1 +/- 6.9 kg/m2, pO2: 65.6 +/- 6.6 mmHg, pCO2: 40.6 +/- 3.1 mmHg, OHS-group: 14 patients, 13 men age: 53.1 +/- 9.3 years, BMI: 53.1 +/- 9.3 kg/m2, pO2: 51.8 +/- 10.5 mmHg, pCO2: 53.8 +/- 9.2 mmHg. The control group consisted of 10 normal weighted subjects. The intrathoracic pressures were assessed by an oesophageal catheter; at the same time, the minute ventilation (VE) and the breathing frequency (fb) were measured via a pneumotachygraph. The area under the pressure-volume loop was correlated to WOB. After reaching steady state VE, fb, and WOB were determined in sitting and supine position. RESULTS: In the OSA-group the apnoea index (AI) was 48.6 +/- 17.7/h and the respiratory disturbance index (RDI) was 66.3 +/- 19.4/h. The forced expiratory volume (FEV1) was 77.3 +/- 23% pred. and the vital capacity (VC) was 76.3 +/- 18.6% pred.; 7 out of 20 patients suffered from chronic bronchitis. In the OHS-group the AI was 21.5 +/- 19/h and the RDI 44.3 +/- 28.2/h. The majority of OHS patients had an airway obstruction (FEV1: 55.8 +/- 17.5% pred., VC: 58.8 +/- 12.8% pred.); 12 out of 14 patients suffered from chronic bronchitis. Compared to the OSA population WOB in the OHS group was significantly higher both in the sitting (0.67 +/- 0.28 J/I versus 1.04 +/- 0.32 J/I, p < 0.001) and supine positions (1.23 +/- 0.25 J/I versus 1.91 +/- 0.43 J/I, p < 0.001). Compared to the sitting position VE and fb did not change significantly in both groups lying supine. CONCLUSIONS: Compared to the OSA group at the same BMI the WOB of the OHS population was significantly increased in the sitting and supine position. The main reason for these findings may be the increased airway obstruction due to chronic bronchitis. Both populations did not change the breathing patterns during the different positions.

Adult↗