Electromagnetic navigation bronchoscopy and rapid on site evaluation added to fluoroscopy-guided assisted bronchoscopy and rapid on site evaluation: improved yield in pulmonary nodules.

AIM: Electromagnetic navigation bronchoscopy (ENB) was reported to increase diagnostic yield in pulmonary nodules (PNs). The aim of this study was to assess if rapid on site evaluation (ROSE) associated with ENB could improve diagnostic accuracy in PNs after non-diagnostic fluoroscopy-guided bronchoscopy added to ROSE. METHODS: Forty patients with PNs suspected for lung cancer underwent to ENB + ROSE after non-diagnostic Fluoroscopy-guided Bronchoscopy + ROSE. Each lesion was studied with reference to size, location, presence of bronchus sign on CT. All lesions were sampled by needle and brush; if negative, by forceps and bronchoalveolar lavage. All patients were followed-up until achievement of definitive diagnosis. RESULTS: Twenty-nine out of 41 lesions (70.7%) had a definitive diagnosis. ENB sensitivity for malignancy was 76.5%, with higher rate in presence of bronchus sign on CT (86.2%) and in case of lesions located in the upper and middle lobes (87.5%). CONCLUSION: ENB is a useful tool in the evaluation of PNs. High diagnostic accuracy may be related to sampling (transbronchial needle aspiration), ROSE, location and presence of bronchus sign.

Similar low frequency of anti-MOG IgG and IgM in MS patients and healthy subjects.

The authors used a liquid-phase radiobinding assay to measure serum anti-myelin oligodendrocyte protein (MOG) immunoglobulin (Ig) G in 87 patients with multiple sclerosis (MS), in 12 patients with encephalomyelitis, and in 47 healthy subjects. Anti-MOG IgM was determined in samples obtained at onset from 40 of 87 patients with MS and in control subjects. The frequency of positive samples with low titers of anti-MOG IgG (< or =5.7%) and IgM (< or =8.3%) was similar in all the groups and subgroups. Binding competition experiments showed that these antibodies had low affinity. Anti-MOG antibodies are not disease specific.

Physiologic response of ventilator-dependent patients with chronic obstructive pulmonary disease to proportional assist ventilation and continuous positive airway pressure.

To investigate the physiologic effects of proportional assist ventilation (PAV) in difficult-to-wean, mechanically ventilated patients with advanced COPD, we measured in eight ICU patients the breathing pattern, neuromuscular drive (P0.1), lung mechanics, and inspiratory muscle effort (PTPdi and PTPpl) during both spontaneous breathing (SB) and ventilatory support with PAV, CPAP, and CPAP + PAV (in random sequence). PAV (volume assist [VA] and flow assist [FA]) was set as follows: dynamic lung elastance and inspiratory pulmonary resistance were measured during SB; then VA and FA were set to counterbalance the elastic and resistive loads exceeding the normal values, respectively, the inspiratory muscles bearing a normal elastic and resistive workload. CPAP was set close to dynamic intrinsic PEEP (8.3 +/- 3.4 cm H2O). We found significant reductions in P0.1 and PTPdi during both CPAP (-45 and -37%, respectively) and PAV (-50 and -48%, respectively). However, only the combination of PAV and CPAP brought P0.1 (1.69 +/- 0.97 cm H2O) and PTPdi (100 +/- 68 cm H2O. s) within normal values, and ameliorated the breathing pattern compared with SB (tidal volume: 0.69 +/- 0.33 versus 0.33 +/- 0.14 L; breathing frequency, 14.6 +/- 4.6 versus 21.0 +/- 6.5 breaths/min, respectively), without generating ineffective inspiratory efforts. We conclude that in difficult-to-wean COPD patients, (1) PAV improves ventilation and reduces both P0.1 and inspiratory muscle effort; (2) the combination of PAV and CPAP can unload the inspiratory muscles to values close to those found in normal subjects.

Static intrinsic PEEP in COPD patients during spontaneous breathing.

Intrinsic positive end-expiratory pressure (PEEPi) is routinely determined under static conditions by occluding the airway at end-expiration (PEEPi,st). This procedure may be difficult in patients with chronic obstructive pulmonary disease (COPD) during spontaneous breathing, as both expiratory muscle activity and increased respiratory frequency often occur. To overcome these problems, we tested the hypothesis that the difference between maximum airway opening (MIP) and maximum esophageal (Ppl max) pressures, obtained with a Mueller maneuver from the end-expiratory lung volume (EELV), can accurately measure PEEPi,st. Using this method, we found that, in eight ventilator-dependent tracheostomized COPD patients (age 71+/-7 yr), PEEPi,st averaged 13.0+/-2.9 cm H2O. That measurement was validated by comparison with a reference static PEEPi (PEEPi,st-Ref) taken at the same EELV adopted by patients during spontaneous breathing, and measured on the passive quasi-static pressure-volume (P/V) curve of the respiratory system, obtained during mechanical ventilation. PEEPi,st-Ref averaged 13.1+/-3.0 cm H2O, i.e., a value essentially equal to PEEPi,st measured by means of our technique. We conclude that PEEPi,st can be accurately assessed in spontaneous breathing COPD patients by the difference between MIP and Ppl max during the Mueller maneuver.

Comparison of invasive and noninvasive saturation monitoring in prescribing oxygen during exercise in COPD patients.

The aim of this study was to determine whether it is possible using ear-oximetry to prescribe the correct oxygen flow rates during exercise in chronic obstructive pulmonary disease (COPD) patients on long-term oxygen therapy (LTOT). Twenty COPD patients on LTOT, with exercise desaturation breathing oxygen at resting flow rates, performed a series of 6-min treadmill walking tests, with a progressive increase in oxygen flows until oxygen saturation measured by ear- or pulse-oximetry (Sp,O2) was above 90%. The exercise studies were repeated the next day, saturation being measured both noninvasively by ear-oximetry (Sp,O2) and invasively by CO-oximeter (Sa,O2). The exercise studies continued until both Sa,O2 and Sp,O2 were above 90%. Reproducibility and agreement of the results were analysed according to Bland and Altman. Sp,O2 was significantly lower than Sa,O2 by, on average, 0.7% (p < 0.004). Sp,O2 reproducibility between the two days was good. The invasive and noninvasive oxygen flow prescriptions agreed in only 10 subjects; in six subjects ear-oximetry over-estimated the oxygen supply (p < 0.0005), whilst in four subjects it underestimated (p < 0.01). Contingency table analysis with coded raw data for the values of the sixth minute (that of the deepest desaturation) showed poor agreement between CO- and pulse-oximetry (Chi-squared p < 0.003). However, theoretically, if the Sp,O2 target had been raised to 93%, there would have been hardly any underestimations of Sa,O2 p = NS). We concluded that noninvasive measurement of oxygen saturation is not adequate for estimating arterial saturation in chronic obstructive pulmonary disease. We suggest, as a working solution, that a new cut-off limit of 93% oxygen saturation measured by pulse oximetry should be used as the value below which exercise-induced desaturation should be corrected in order to allow oxygen to be properly prescribed during activities of daily life.

Partitioning of inspiratory muscle workload and pressure assistance in ventilator-dependent COPD patients.

To investigate the mechanisms underlying ventilator-dependence in patients with chronic obstructive pulmonary disease (COPD), and to assess the effects of the combination of positive end-expiratory pressure (PEEP) and pressure-support ventilation (PSV) on inspiratory muscle effort, we investigated respiratory mechanics in eight ventilator-dependent COPD patients. The patients' breathing pattern, lung mechanics, diaphragmatic effort (PTPdi), diaphragmatic tension-time index (TTdi), and arterial blood gases were measured during both spontaneous breathing (SB) and ventilatory assistance consisting of PSV alone (15, 20, and 25 cm H2O) and PSV combined with a PEEP of 5 cm H2O (reducing PSV to 10, 15, and 20 cm H2O, respectively, to maintain equivalent inspiratory pressure). The different levels of ventilatory support were delivered in a randomized sequence. Maximal inspiratory (MIP), esophageal (PpImax) and transdiaphragmatic (Pdi(max)) pressures and respiratory drive (P(0.1)) were measured at the beginning of the procedure during SB. We found a high P(0.1) (6.1 +/- 1.7 cm H2O), which seemed to rule out an impairment of respiratory-center output. Apparently, inspiratory muscle strength was compatible with successful weaning (38.5 +/- 8.8, 50.9 +/- 9.7, and 51.8 +/- 9.5 cm H2O for MIP, PPImax and Pdi(max), respectively). However, abnormal respiratory mechanics (particularly an intrinsic positive end-expiratory pressure (PEEPi) of 8.3 +/- 1.9 cm H2O and pulmonary resistance 24.7 +/- 9.5 cm H2O/L/s imposed an excessive load on the inspiratory muscles, as indicated by a high PTPdi (499 +/- 122 cm H2O x s). Increasing levels of PSV progressively and significantly unloaded the patients' inspiratory muscles, although at pressures above 20 cm H2O uncoupling occurred between patient and ventilator respiratory frequency. Application of PEEP during PSV improved ventilatory assistance by further reducing the inspiratory effort (by 17% on average) and by ameliorating patient-ventilator interaction. We conclude that the excessive mechanical load, and in particular the high PEEPi, is the major determinant of ventilator-dependence in COPD patients. Application of PEEP improves the efficiency of PSV in unloading these patients' inspiratory muscles, and can sometimes improve patient-ventilator interaction.

Intermediate respiratory care unit: admission criteria.

Intensive care unit (ICU) management of patients on partial ventilatory support is very costly. We opened an intermediate respiratory care unit (RCU), with the aim of providing cost beneficial in-hospital and home care for patients who require mechanical ventilation for at least 8 h.day-1. Prior to admission to an intermediate RCU, it is mandatory to take into consideration not only the patient's overall health status but also his or her prognosis, and rehabilitation chances and environmental factors have to be evaluated.

Physiologic effects of positive end-expiratory pressure and mask pressure support during exacerbations of chronic obstructive pulmonary disease.

To assess physiologic effects of continuous positive airway pressure (CPAP) and positive end-expiratory pressure (PEEP) during noninvasive pressure support ventilation (PSV) in patients with acute exacerbation of chronic obstructive pulmonary disease (COPD), we measured in seven patients the breathing pattern, lung mechanics, diaphragmatic effort (PTPdi), and arterial blood gases under four conditions: (1) spontaneous breathing (SB); (2) CPAP; (3) PSV of 10 cm H2O; and (4) PSV plus PEEP (PEEP + PSV). CPAP and PEEP were set between 80 and 90% of dynamic intrinsic PEEP (PEEPidyn) measured during SB and PSV, respectively. PEEPidyn was obtained (1) from the decrease in pleural pressure (delta Ppl) preceding inspiration, and (2) subtracting the fall in gastric pressure (delta Pga) caused by relaxation of the abdominal muscles from the delta Ppl decrease. Abdominal muscle activity made PEEPidyn overestimated in almost all instances (p < 0.0001). PSV increased minute ventilation, improved gas exchange, and decreased PTPdi. PEEP added to PSV, likewise CPAP compared with SB, further significantly decreased the diaphragmatic effort (PTPdi went from 322 +/- 111 to 203 +/- 63 cm H2O.s) by counterbalancing PEEPidyn, which went from 5.4 +/- 4.0 to 3.1 +/- 2.3 cm H2O. These data support the use of low levels of PEEP (80 to 90% of PEEPidyn) to treat acute exacerbation of COPD by means of mask PSV.

Home mechanical ventilation in kyphoscoliosis.

The aim of the study was to determine whether intermittent positive pressure ventilation (IPPV), delivered either by nasal mask or by tracheostomy, is able to improve alveolar gas exchange in kyphoscoliotic patients with respiratory failure. We evaluated 17 patients, 10 females and 7 males, aged 52 +/- 12 (mean +/- SD) yrs. Eight had severe respiratory failure (arterial oxygen tension (PaO2) 53.2 +/- 9.3 mmHg (7.1 +/- 1.2 kPa); arterial carbon dioxide tension (PaCO2) 73.3 +/- 12.5 mmHg (9.7 +/- 1.6 kPa), breathing supplemental oxygen), and were put on IPPV via tracheostomy (TIPPV). The others (PaO2 54.5 +/- 5.5 mmHg (7.3 +/- 0.7 kPa); PaCO2 57.9 +/- 7 mmHg (7.7 +/- 0.9 kPa), breathing air), were put on IPPV via nasal mask (NIPPV). Home mechanical ventilation (HMV) was performed at night (7 +/- 1 h) by means of a volume-cycled pressure respirator in control mode. The frequency was adapted to the patient's spontaneous respiratory rate, and then eventually modified according to blood gases. A silicone mask was moulded onto the patient's nose. Supplemental oxygen (to maintain arterial oxygen saturation (SaO2) > 90%) was used only for tracheostomized patients, whereas NIPPV was performed with fractional inspiratory oxygen (FIO2) 21%. Arterial blood samples were obtained for all patients in steady-state condition, 8 +/- 1 h from the withdrawal, breathing air, after 1 and 6 months of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Reductions in exercise lactic acidosis and ventilation as a result of exercise training in patients with obstructive lung disease.

Though exercise training is part of most pulmonary rehabilitation programs, whether there is a physiologic basis for increased exercise tolerance is unclear. We sought to determine whether patients with chronic obstructive pulmonary disease (COPD) are capable of obtaining a physiologic training effect, as manifested by a reduction in blood lactate and ventilation (VE) at a given level of exercise. We also sought to determine whether training work rate determines the size of the training effect. Nineteen participants with COPD of predominantly moderate severity in an inpatient rehabilitation program performed two cycle ergometer exercise tests at a low and a high work rate for 15 min or to tolerance and also an incremental exercise test to tolerance. Arterial blood was sampled for blood gas and lactate analyses. Identical tests were performed before and after 5-day-per-week cycle ergometer training for 8 wk either for 45 min/day at a high work rate (average, 71 W) or for a proportionally longer time at a low work rate (average, 30 W). Average FEV1 was 56 +/- 12% predicted and did not change with training. Peak exercise lactate (average, 6.5 mEq/L) was not correlated with FEV1. For the high work rate training group, identical work rates engendered less lactate (4.5 versus 7.2 mEq/L) and less VE (48 versus 55 L/min) after training; the low work rate training group had significantly less lactate and VE decrease (p less than 0.01). Further, endurance time for the high constant work rate increased 73% in the high work rate training group but only 9% in the low work rate training group. At identical work rates, VE decrease average 2.5 L/min per mEq/L decrease in lactate (r = 0.75). We conclude that most COPD subjects studied increased blood lactate at low work rates. Many of these patients were able to achieve a physiologic training effect. Though total work was the same, training at a high work rate was more effective than was training at a low work rate. The lower VE requirement to perform exercise was in proportion to the lower lactate level, but the VE decrease for a given decrease in lactate was smaller than that seen in normal subjects (7.2 L/min/mEq/L), apparently because patients with COPD fall to hyperventilate in response to lactic acidosis (PaCO2 does not drop). These findings provide a physiologic rationale for exercise training of patients with COPD.

A new perspective in pulmonary rehabilitation: anaerobic threshold as a discriminant in training.

Exercise training is a mainstay of many pulmonary rehabilitation programmes. However, the physiologic basis for improved exercise tolerance is unclear. We hypothesized that since endurance training is known to reduce blood lactate at levels of work above the anaerobic threshold (AT), minute ventilation (VE) would also be lower. This might be an important benefit for the ventilatory-limited patient. We studied 10 normal subjects who performed 15 min of exercise at each of 4 work rates before and after 8 weeks of training. The lowest work rate was chosen to be below the AT; training produced a minimal decrease in VE (2.5 l.min-1). For the highest work rate, training produced a 4 mEq.l-1 decrease in lactate and a 37 l.min-1 decrease in VE. End-exercise VE reduction was well correlated with lactate reduction (r = 0.69). Seven men with chronic obstructive pulmonary disease (COPD) have also been studied. Each performed an incremental exercise test and two constant work rate tests (one above and one below AT) before and after an 8 week training period. Though responses were more variable than in normal subjects, training produced a reduced ventilatory requirement for exercise when blood lactate was reduced.