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Biomedical subjects

M Vitacca

Publications and source records attributed to M Vitacca.

At least 19 recordsLinked to original sources
PubMed2006

Maximal inspiratory and expiratory pressure measurement in tracheotomised patients.

The present study compared four different sites and conditions for the measurement of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) in 38 spontaneous breathing tracheotomised patients. Of the patients, 28 had chronic obstructive pulmonary disease (COPD). The four different conditions were: 1) through a cuff inflated cannula (condition A); 2) through the mouth with a deflated cannula (condition B); 3) through the mouth with a phonetic uncuffed cannula (condition C); and 4) through the mouth after stoma closure (condition D). Five trials in each condition were performed using a standardised method. The measurement of both MIP and MEP differed significantly depending on the condition of measurement. MIP taken in condition A was significantly higher when compared with conditions B, C and D. MEP in condition A was significantly higher when compared with condition B and D. In condition A the highest frequency of the best measurement of MIP and MEP was observed at the fourth and fifth effort, respectively. The same results were obtained after the selection of only COPD patients. In conclusion, respiratory muscle assessment differs significantly depending on measurement condition. Measurement through inflated cannula tracheotomy yields higher values of both maximal inspiratory and maximal expiratory pressure.

Aged↗
PubMed2006

A pilot study of nurse-led, home monitoring for patients with chronic respiratory failure and with mechanical ventilation assistance.

We assessed the feasibility of telemedicine for home monitoring of 45 patients with chronic respiratory failure (CRF) discharged from hospital. The patients transmitted pulsed arterial saturation (pSat) data via a telephone modem to a receiving station where a nurse was available for a teleconsultation. A respiratory physician was also available. Scheduled and ad hoc appointments were conducted. Thirty-five patients were on home mechanical ventilation, 13 with invasive and 22 with non-invasive devices. The main diagnosis was chronic obstructive pulmonary disease (COPD). The follow-up period was 176 days (SD 69). In all, 376 calls for scheduled consultations were received and 83 ad hoc consultations were requested by the patients. The actions taken were: 55 therapy modifications, 19 hospitalizations in a respiratory department for decompensated CRF, three hospitalizations in an intensive care unit (ICU), 22 requests for further investigations, 25 contacts with the general practitioner (GP), 66 demands for respiratory consultations and 10 calls for the emergency department. The mean time recorded for the 459 calls was 16 min/patient/week. In 82% of calls, a pSat recording was received successfully. The nurse time required to train the users in the operation of the pSat instrument was high (mean time 30 min). However, the results showed that home monitoring was feasible, and useful for titration of oxygen, mechanical ventilation setting and stabilization of relapses.

Chronic Disease↗
PubMed2005

Lung and respiratory muscle function at discharge from a respiratory intensive care unit.

BACKGROUND: The purpose of this prospective observational study was to describe lung and respiratory muscle function at Respiratory Intensive Care Unit (RICU) discharge after a severe exacerbation of Chronic Obstructive Pulmonary Disease (COPD). METHODS: The study was conducted in 42 consecutive COPD patients in whom arterial blood gases, dynamic and static lung volumes, maximal inspiratory pressure (MIP) were assessed at discharge from the RICU and compared with values measured 6 months previously when they were in a stable state. The same measurements were performed at 6-month interval in 42 comparable stable COPD patients not requiring any hospitalisation for at least 6 months used as controls. RESULTS: 24% of patients in the study group were discharged with hypercapnia whereas they were normocapnic before the acute episode. Compared to prior to exacerbation, patients of study group showed a significant worsening in mean values of PaCO2 (p=0.005), MIP (p=0.005) and FEV1 (p=0.041). Predefined criteria of worsening in PaCO2, MIP and FEV1 were observed in 47%, 33% and 28% of patients in study respectively. Neither lung nor respiratory muscle function in last stable state did predict post RICU functional worsening. In a period of 6 months controls showed no change in the studied parameters. CONCLUSIONS: After a severe acute exacerbation requiring admission to a RICU and immediately before discharge 1) a large proportion of COPD patients still show preserved lung and respiratory muscle function 2) more than one third of them would require further care and rehabilitative attempts to restore functional derangements.

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PubMed2002

Exhaled nitric oxide and exercise tolerance in severe COPD patients.

To answer the question as to whether pulmonary rehabilitation programs (PRP) induced increase in exercise tolerance (ET) is associated with increased levels of exhaled nitric oxide (eNO) in COPD patients of different degrees of severity, we designed a prospective and controlled study. Forty-seven stable COPD patients underwent an 8-week outpatient multidisciplinary PRP including supervised incremental exercise. Fractional eNO concentration (FE(NO)) and peak work-rate (W(peak) were assessed baseline (T-1), atthe end of 1-month run-in period (T0), and after (T1) the PRP. Lung function, walking test, health-related quality of life (HRQL) were also recorded. Patients were divided into three groups according to disease severity: 17 severe [FEV1 35 (5)% pred] COPD patients, seven of them with cor pulmonale; 15 mild [FEV1 78 (6)% pred], and 15 moderate [FEV1 56 (6)% pred] COPD patients. FE(NO) did not differ at T-1 and T0 (mean absolute change (SD): 0.03 (0.09) 95% CI-0.01, 0.16, 0.06 (1.03) 95% CI 0.03, 0.75 and 0.05 (0.06) 95% CI 0.02, 0.11 ppb in mild, moderate and severe patients, respectively). As compared to T0, both W(peak) (by 17,15 and 10%, respectively) and FE(NO) (by 29, 24 and 16%, respectively) significantly increased in all groups, but not in patients with cor pulmonale. A significant correlation between pre- and post-PRP changes in Wpeak and FE(NO) was found both in mild to moderate (r = 0.79, P < 0.00001) and severe (r = 0.76, P < 0.001) COPD patients. After a PRP, improvement in ET is associated with an increase in eNO also in most severe COPD patients, but not in those with cor pulmonale.

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PubMed2002

Lack of additional effect of adjunct of assisted ventilation to pulmonary rehabilitation in mild COPD patients.

Different modalities of assisted ventilation improve breathlessness and exercise tolerance in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to evaluate the effects of the addition of assisted ventilation during exercise training on the outcome of a structured pulmonary rehabilitation programme (PRP) in COPD patients. Thirty-three male patients with stable COPD (mean (SD) forced expiratory volume in 1 s (FEV1) 44 (16) % pred), without chronic ventilatory failure, undergoing a 6-week multidisciplinary outpatient PRP including exercise training, were randomised to training during either mask proportional assist ventilation (PAV: 18 patients) or spontaneous breathing (SB: 15 patients). Assessment included exercise tolerance, dyspnoea, leg fatigue, and health-related quality of life (HRQL). Five out of 18 patients (28%) in the PAV group dropped out due to lack of compliance with the equipment. Both groups showed significant post-PRP improvements in exercise tolerance (peak work rate difference: 20 (95% Cl 2.4-37.6) and 14 (3.8% CI to 24.2) W in PAV and SB group, respectively), dyspnoea and leg fatigue, but not in HRQL, without any significant difference between groups. It is concluded that with the modality and in the patients assessed in this study assisted ventilation during training sessions included in a multidisciplinary PRP was not well tolerated by all patients and gave no additional physiological benefit in comparison with exercise training alone.

Aged↗
PubMed2001

Physiological response to pressure support ventilation delivered before and after extubation in patients not capable of totally spontaneous autonomous breathing.

We designed a prospective, physiological study in 12 patients affected by chronic respiratory disorders. The study was aimed at assessing the diaphragm energy expenditure (PTPdi), lung resistance (RL) and elastance (EL), arterial blood gases (ABG), breathing pattern, and dyspnea measured by a visual analog scale during invasive pressure support ventilation (i-PSV) and noninvasive PSV (n-PSV). The ventilator settings were kept the same. Both i-PSV and n-PSV significantly reduced the PTPdi per minute, compared with that during a T-piece trial (204.4 +/- 93.8 cm H(2)O x s/min [i-PSV]; 197.5 +/- 119.8 [n-PSV]; 393.8 +/- 129.0 [T-piece]). Expired tidal volume (VTe) was significantly higher (p < 0.05) during n-PSV (615 +/- 166 ml) than during i-PSV (519 +/- 140 ml). The respiratory pump (PTPdi/VTe) was more effective (p < 0.05) with noninvasive ventilation (22.3 +/- 2.3 cm H(2)O x s/L for i-PSV versus 17.2 +/- 3.3 for n-PSV). RL and EL were similar with the two modes of ventilation. Overall dyspnea was significantly (p < 0.05) better during n-PSV than i-PSV, whereas ABG were similar. We have shown, in patients affected by stable chronic respiratory disorders not ready to sustain totally spontaneous breathing, that i-PSV and n-PSV are equally effective in reducing the PTPdi and in improving ABG, but that n-PSV seems to be better tolerated.

Acute Disease↗
PubMed2001

Comparison of two methods for weaning patients with chronic obstructive pulmonary disease requiring mechanical ventilation for more than 15 days.

We designed a prospective multicenter randomized controlled study in three long-term weaning units (LWU) to evaluate which protocol, inspiratory pressure support ventilation (PSV) or spontaneous breathing trials (SB), is more effective in weaning patients with chronic obstructive pulmonary disease (COPD) requiring mechanical ventilation for more than 15 d. Fifty-two of 75 patients, failing an initial T-piece trial at admission, were randomly assigned to PSV or SB (26 in both groups). No significant difference was found in weaning success rate (73% versus 77% in the PSV and SB group, respectively), mortality rate (11.5% versus 7.6%), duration of ventilatory assistance (181 +/- 161 versus 130 +/- 106 h), LWU (33 +/- 12 versus 35 +/- 19 d), or total hospital stay. The results of these defined protocols were retrospectively compared with an "uncontrolled clinical practice" in weaning historical control patients. The overall 30-d weaning success rate was significantly greater (87% versus 70%) and the time spent under mechanical ventilation by survived and weaned patients was shorter in the patients in the study than in historical control patients (103 +/- 144 versus 170 +/- 127 h). The LWU and hospital stays were also significantly shorter (27 +/- 12 versus 38 +/- 18 and 38 +/- 17 versus 47 +/- 18 d). Spontaneous breathing trials and decreasing levels of PSV are equally effective in difficult-to-wean patients with COPD. The application of a well-defined protocol, independent of the mode used, may result in better outcomes than uncontrolled clinical practice.

Aged↗
PubMed2001

Effect of pulmonary rehabilitation on exhaled nitric oxide in patients with chronic obstructive pulmonary disease.

BACKGROUND: In patients with mild to moderate chronic obstructive pulmonary disease (COPD) the exercise induced increase in exhaled nitric oxide (eNO) parallels that observed in normal untrained subjects. There is no information on the effects of the level of exercise tolerance on eNO in these patients. The aim of this study was to evaluate the effect of a pulmonary rehabilitation programme including exercise training on eNO in patients with COPD. METHODS: In 14 consecutive male patients with stable COPD of mean (SD) age 64 (9) years and forced expiratory volume in one second (FEV1) 55 (14)% predicted, fractional eNO concentration (FeNO), peak work rate (Wpeak) and oxygen uptake (VO2peak) were assessed at baseline (T-1), at the end of a 1 month run in period (T0), and after an 8 week outpatient multidisciplinary pulmonary rehabilitation programme (T1) including cycloergometer training. RESULTS: FeNO did not significantly differ at T-1 and T0 (mean (SE) 4.3 (0.6) and 4.4 (0.6) ppb, respectively), whereas it rose significantly at T1 to 6.4 (0.7) ppb (p<0.02). Compared with T0, both Wpeak and VO2 were significantly (p<0.05) increased at T1 (mean (SE) Wpeak from 89 (5.6) W to 109 (6.9) W); VO2peak from 1.27 (0.1) l/min to 1.48 (0.1) l/min). A significant correlation was found between baseline FEV1 and the change in FeNO following the rehabilitation programme (r=-0.71; p<0.05) and between changes in FeNO and Wpeak from T0 to T1(r=0.60; p<0.05). CONCLUSIONS: Pulmonary rehabilitation in patients with mild to moderate COPD is associated with an increase in exhaled nitric oxide.

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PubMed2001

In-hospital short-term training program for patients with chronic airway obstruction.

OBJECTIVE: To compare the functional benefits and relative costs of administering an intense short-term inpatient vs a longer outpatient pulmonary rehabilitation program (PRP) for patients with chronic airway obstruction (CAO). DESIGN: Retrospective case-control study. SETTING: Pulmonary ward and outpatient clinic of a rehabilitation center. PATIENTS: Forty-three patients (case subjects) selected on the basis of selection criteria were compared with control subjects matched to them for age, sex, FEV(1), and diagnosis of either COPD or asthma. Case subjects performed 10 to 12 daily sessions (5 sessions a week) of inpatient PRP; control subjects performed 20 to 24 sessions (3 sessions a week) of outpatient PRP. MEASUREMENTS: At baseline and after the PRP, an incremental exercise test was performed, including evaluation of dyspnea and leg fatigue by Borg scale (D and F, respectively) at each workload step. The cost of PRP was also evaluated. RESULTS: Both PRPs resulted in similar significant improvements in cycloergometry peak workload (from 68 +/- 18 to 82 +/- 22 and from 75 +/- 17 to 87 +/- 27 W in case subjects and control subjects, respectively), isoload D (from 6.4 +/- 1.6 to 4.2 +/- 1.8 for case subjects and from 8.5 +/- 1.9 to 6.3 +/- 2.4 for control subjects) and isoload F (from 6.6 +/- 1.8 to 4.2 +/- 1.8 for case subjects and from 8.9 +/- 1.9 to 7.0 +/- 1.8 for control subjects). Although the single daily session was less expensive, the outpatient PRP total costs were greater because of the higher number of sessions and the cost of daily transportation. CONCLUSIONS: In patients with CAO, a shorter inpatient PRP may result in improvement in exercise tolerance similar to a longer outpatient PRP but with lower costs. Whether a shorter outpatient PRP may get physiologic and clinical benefits, while further reducing costs, must be evaluated by future controlled, randomized, prospective studies.

Ambulatory Care↗
PubMed2001

Exacerbations of COPD: predictive factors, treatment and outcome.

Chronic obstructive pulmonary disease (COPD) is a leading cause of death, and constitutes a major medical and an increasing economic problem for acute and long term care. A low level of irreversible airway obstruction when in stable condition, hypercapnia, hypoxia, the presence of comorbid heart disease, right ventricular failure, and low serum albumin are the main factors related to risk of exacerbations. Bronchial infections, bronchospasm, left ventricular failure, pneumonia, pneumothorax and thromboembolism are described as the most frequent relapsing causes of COPD. During exacerbation, the inflammatory process, the ventilation/perfusion (V'A/Q') mismatching, an increased airflow resistance and dynamic hyperinflation (PEEPidyn) expose the respiratory muscles to the risk of fatigue, eventually leading to ventilatory pump failure and rising hypercapnia. Prevention of exacerbations and subsequent hospitalisations may be obtained with careful rehabilitation programs, a strict drug protocol, long term oxygen therapy and sometimes using home noninvasive mechanical ventilation (NMV). During exacerbation proper management of infection and lung mechanics derangement has to be adopted using an accurate assessment of severity and standardized treatment protocols. Patient history and examination and functional tests are beneficial to decide how and where to treat these patients. Mechanical ventilation (possibly noninvasive) may be required to reverse the acute episode. The aims of all these procedures remain: i) to prolong length and quality of life; ii) to save costs. Both hospital and post-discharge mortality of exacerbated COPD remain high while quality of life appears to be poor. Future studies will elucidate the relation between number and severity of exacerbations and prognosis.

Combined Modality Therapy↗
PubMed2000

Preliminary results on nursing workload in a dedicated weaning center.

OBJECTIVE: To evaluate the nursing time required for difficult-to-wean patients in a dedicated weaning center (WC) and to examine the correlation of the nursing time with nursing workload (NW) scores and with clinical severity and dependency. SETTING: Four-bed WC of a pulmonary rehabilitation department. INTERVENTION: None. DESIGN AND MEASUREMENT: Prospective, observational study of 46 consecutive patients admitted to a long-term WC. Time required by items of the Time Oriented Score System (TOSS) and other tasks specific to respiratory intermediate intensive care units were evaluated for all the activities performed on each patient in the first 2 days after admission. Patient dependency and level of nursing care at admission were measured using the Dependence Nursing Scale (DNS) and the Intermediate Therapeutic Intervention Score System (TISS-int). The Acute Physiology and Chronic Health Evaluation (APACHE) II score was also recorded at admission. RESULTS: On the first day each patient needed 45 +/- 15% (63 +/- 23%, 45 +/- 22%, and 29 +/- 14% for the three nursing shifts) of allocated single nursing time. On the TOSS on the first day patients required a daily mean 28 +/- 10% of total available nursing time; on the second day the results did not change. Time of care in the first 24 h was only weakly related to DNS, APACHE II score, and TISS-int; only DNS was able (although weakly; r = 0.45) to predict minutes of nursing care. CONCLUSIONS: In difficult-to-wean patients from mechanical ventilation the nursing time in the first 2 days after admission is high. The use of TOSS may underestimate NW by about 38%. Although only DNS showed the ability to predict minutes of care, the weak relationship limits its value in clinical practice.

Aged↗
PubMed2000

Nasal proportional assist ventilation unloads the inspiratory muscles of stable patients with hypercapnia due to COPD.

This study was undertaken to assess the physiological effects of proportional assist ventilation (PAV), administered noninvasively through a nose mask, on ventilatory pattern, arterial blood gases, lung mechanics, and inspiratory muscle effort in stable, hypercapnic patients with chronic obstructive pulmonary disease. In 15 patients, PAV was set by adjusting volume assist (VA) and flow assist (FA) according to the "run-away" technique and the patient's comfort respectively. The level of support was fixed at 80% of the total possible assistance and averaged 13.9+/-4.1 cmH2O x L(-1) and 4.1+/-1.3 cmH2O x L(-1) x s for VA and FA, respectively. Continuous positive airway pressure (CPAP) was established at 2 cmH2O and then increased to 5 cmH2O. Physiological measurements were made during spontaneous breathing (SB), after more than 40 min of PAV, and 20 min after the rise in CPAP. On average, PAV improved ventilation (10.3+/-2.1 to 12.5+/-2.0 L x m(-1)), tidal volume (0.60+/-0.11 to 0.76+/-0.24 L), arterial oxygen tension and arterial carbon dioxide pressure (from 6.7+/-0.7 to 7.1+/-0.9 and from 7.6+/-1.0 to 7.2+/-1.2 kPa, respectively). During SB, pulmonary resistance and dynamic lung elastance averaged 15.0+/-7.6 cmH2O x L(-1) s and 15.8+/-8.0 cmH2O x L(-1), respectively. Assuming a normal chest wall elastance (5 cmH2O x L(-1)), VA and FA relieved respectively approximately 70% of the elastic and 30% of the resistive burden, with PAV set with the procedure of this study. The overall magnitude of the patients' inspiratory effort, measured by means of the oesophageal and diaphragmatic pressure time product in 10 patients was significantly reduced by PAV, on average, 328+/-122 to 226+/-118 (-31%) and 361+/-119 to 254+/-126 (-30%) cmH2O x min(-1), respectively. In 10 patients the electrical activity of the diaphragm (Edi) was also reduced by PAV to approximately 70%, on average, of the SB activity. The rise of CPAP 25 cmH2O did not cause any further significant change in the physiological variables. In all instances there was a good patient-ventilator interaction, the ventilatory breath never entering into the patient's neural expiratory time. These data show that nasal proportional assist ventilation can provide physiological benefits to the stable hypercapnic chronic obstructive pulmonary disease patients. In fact, proportional assist ventilation, which was well tolerated by all patients, unloaded the inspiratory muscles and improved arterial blood gases. Further studies can clarify whether these beneficial physiological effects of nasal proportional assist ventilation can bear profitable consequences in the overall clinical management of chronic obstructive pulmonary disease patients with chronic carbon dioxide retention.

Aged↗
PubMed2000

Physiologic effects of early administered mask proportional assist ventilation in patients with chronic obstructive pulmonary disease and acute respiratory failure.

OBJECTIVE: To evaluate the physiologic short-term effects of noninvasive proportional assist ventilation (PAV) in patients with acute exacerbation of chronic obstructive pulmonary disease (COPD). DESIGN: Prospective, physiologic study. SETTING: Respiratory intermediate intensive care unit. PATIENTS: Seven patients with acute respiratory failure requiring noninvasive mechanical ventilation because of exacerbation of COPD. INTERVENTIONS: PAV was administered by nasal mask as first ventilatory intervention. The setting of PAV involved a procedure to adjust volume assist and flow assist to levels corresponding to patient comfort. Volume assist was also set by means of the "run-away" procedure. Continuous positive airway pressure (CPAP) amounting to 2 cm H2O was always set by the ventilator. This setting of assistance (PAV) was applied for 45 mins. Thereafter, CPAP was increased to 5 cm H2O (PAV + CPAP-5) without any change in the PAV setting and was administered for 20 mins. Oxygen was delivered through a port of the mask in the attempt to maintain a target SaO2 >90%. MEASUREMENTS AND MAIN RESULTS: Arterial blood gases, breathing pattern, and inspiratory effort were measured during unsupported breathing and at the end of PAV, and breathing pattern and inspiratory effort were measured after 20 mins of PAV + CPAP-5. PAV determined a significant increase in tidal volume and minute ventilation (+64% and +25% on average, respectively) with unchanged breathing frequency and a significant improvement in arterial blood gases (PaO2 with the same oxygen supply, from 65 +/- 15 torr to 97 +/- 36 torr; PaCO2, from 80 +/- 11 torr to 76 +/- 13 torr; pH, from 7.30 +/- 0.02 to 7.32 +/- 0.03). The pressure-time product calculated over a period of 1 min (from 318 +/- 87 to 205 +/- 145 cm H2O x sec x min(-1)) was significantly reduced. PAV + CPAP-5 resulted in a further although not significant decrease in the pressure-time product calculated over a period of 1 min (to 183 +/- 110 cm H2O x sec x min(-1)), without additional changes in the breathing pattern. CONCLUSIONS: Noninvasive PAV is able to improve arterial blood gases while unloading inspiratory muscles in patients with acute exacerbation of COPD.

Acute Disease↗
PubMed2000

Exhaled nitric oxide and exercise in stable COPD patients.

STUDY OBJECTIVE: To evaluate exhaled nitric oxide (eNO) during exercise in patients with stable COPD. SETTING: Outpatient evaluation in a rehabilitation center. PATIENTS: Eleven consecutive male patients with stable COPD (age, 65 +/- 6 years; FEV(1), 56 +/- 10% predicted). Eight healthy (six men; age, 51 +/- 16 years) nonsmoking, nonatopic volunteers served as control subjects. METHODS: In each subject, a symptom-limited cycle ergometry test was performed by monitoring eNO with the tidal-breath method to assess eNO concentration (FENO) and output (VNO) at rest, peak exercise, and recovery time. RESULTS: Resting FENO (9.8 +/- 5.1 and 14.1 +/- 6.3 parts per billion, respectively) and VNO (4.2 +/- 2.0 and 5.9 +/- 3.4 nmol/min, respectively) were lower, although not significantly, in COPD patients than in control subjects. In both groups, FENO significantly decreased whereas VNO significantly increased during exercise. Both variables returned to baseline during the recovery time. Peak exercise VNO, but not FENO, was significantly lower in COPD patients than in control subjects (7.9 +/- 5.4 and 12.7 +/- 6.0 nmol/min, respectively, p < 0.05). The rise in VNO was weakly correlated to oxygen consumption VO(2)) both in control subjects (r = 0.31, p = 0. 002) and in COPD patients (r = 0.22, p = 0.03). FENO showed an inverse correlation to VO(2) in both groups (r = -0.53, p = 0.000; r = -0.31, p = 0.003 in control subjects and COPD patients, respectively). CONCLUSIONS: In patients with mild and moderate COPD, eNO during exercise parallels that observed in normal control subjects. VNO, but not FENO, is significantly reduced at peak exercise in COPD patients as compared with control subjects. The long-term effects of exercise training on eNO has to be evaluated by further studies.

Adult↗
PubMed2000

Negative pressure ventilation vs external high-frequency oscillation during rigid bronchoscopy. A controlled randomized trial.

STUDY OBJECTIVES: To compare the effectiveness of two modalities of external ventilation during rigid bronchoscopy: intermittent negative pressure ventilation (INPV) and external high-frequency oscillation (EHFO). DESIGN: Prospective, controlled, randomized, nonblinded study. SETTING: University-affiliated hospital. PATIENTS: Seventy patients undergoing interventional rigid bronchoscopy for tracheobronchial lesions were enrolled into the study. INTERVENTIONS: Mechanical ventilation was performed by INPV or EHFO. When pulse oximetry was < 90%, manually assisted ventilation was delivered. MEASUREMENTS AND RESULTS: Arterial blood gases were sampled preoperatively and intraoperatively. Most patients in both groups had normal intraoperative PaCO(2) (mean, 43. 6 +/- 11.8 mm Hg under EHFO and 37.4 +/- 8.2 mm Hg under INPV; p = 0.012), and acidemia occurred in 9 of 35 patients of EHFO group and in 2 of 35 patients of INPV group (p = 0.049). Hypercapnia (PaCO(2) > 50 mm Hg) was observed in 10 patients under EHFO and in 2 with INPV (p = 0.026). Intraoperative mean PaO(2) was similar (101.4 +/- 52.9 mm Hg with EHFO and 124.2 +/- 50.3 mm Hg with INPV; p = 0.07), but O(2) supply was different (3.5 +/- 2.3 L/min during INPV and 8.5 +/- 6.2 L/min during EHFO; p < 0.001). Intraoperative hypoxemia (PaO(2) < 60 mm Hg) occurred in five patients with EHFO and two with INPV (p = 0.426). Three EHFO patients required manually assisted ventilation (mean, 0.2 +/- 0.9), but no INPV patient did (p = 0.142). CONCLUSIONS: External negative pressure ventilation appears to be a suitable choice during rigid bronchoscopy: both EHFO and INPV ensure effective ventilation and comfortable operating conditions in the majority of patients. Some patients may receive inadequate ventilation with EHFO, developing respiratory acidosis and requiring manually assisted ventilation. In comparison with INPV, EHFO requires a higher fraction of inspired oxygen.

Adult↗
PubMed2000

The appropriate setting of noninvasive pressure support ventilation in stable COPD patients.

STUDY OBJECTIVE: To evaluate the short-term physiologic effects of two settings of nasal pressure-support ventilation (NPSV) in stable COPD patients with chronic hypercapnia. DESIGN: Randomized controlled physiologic study. SETTING: Lung function units and outpatient clinic of two affiliated pulmonary rehabilitation centers. PATIENTS: Twenty-three patients receiving domiciliary nocturnal NPSV for a mean (+/- SD) duration of 31 +/- 20 months. METHODS: Evaluation of arterial blood gases, breathing pattern, respiratory muscles, and dynamic intrinsic positive end-expiratory pressure (PEEPi,dyn) during both unassisted and assisted ventilation. Two settings of NPSV were randomly applied for 30 min each: (1) usual setting (U), the setting of NPSV actually used by the individual patient at home; and (2) physiologic setting (PHY), the level of inspiratory pressure support (IPS) and external positive end-expiratory pressure (PEEPe) tailored to patient according to invasive evaluation of respiratory muscular function and mechanics. RESULTS: All patients tolerated NPSV well throughout the procedure. Mean U was IPS, 16 +/- 3 cm H(2)O and PEEPe, 3.6 +/- 1.4 cm H(2)O; mean PHY was IPS, 15 +/- 3 cm H(2)O and PEEPe, 3.1 +/- 1.6 cm H(2)O. NPSV was able to significantly (p < 0.01) improve arterial blood gases independent of the setting applied. When compared with spontaneous breathing, both settings induced a significant increase in minute ventilation (p < 0.01). Both settings were able to reduce the diaphragmatic pressure-time product, but the reduction was significantly greater with PHY (by 64%; p < 0.01) than with U (56%; p < 0.05). Eleven of 23 patients (48%) with U and 7 of 23 patients (30%) with PHY showed ineffective efforts (IE); the prevalence of IE (20 +/- 39% vs 6 +/- 11% of their respiratory rate with U and PHY, respectively) was statistically different (p < 0.05). CONCLUSION: In COPD patients with chronic hypercapnia, NPSV is effective in improving arterial blood gases and in unloading inspiratory muscles independent of whether it is set on the basis of patient comfort and improvement in arterial blood gases or tailored to a patient's respiratory muscle effort and mechanics. However, setting of inspiratory assistance and PEEPe by the invasive evaluation of lung mechanics and respiratory muscle function may result in reduction in ineffective inspiratory efforts. These short-term results must be confirmed in the long-term clinical setting.

Aged↗