Inflamed shoulder structures in polymyalgia rheumatica with normal erythrocyte sedimentation rate.

OBJECTIVE: To investigate the inflammatory involvement of shoulder articular and extraarticular structures in polymyalgia rheumatica (PMR) patients with a normal erythrocyte sedimentation rate (ESR) at diagnosis. METHODS: This was a case-control study. All consecutive, untreated new outpatients diagnosed as having PMR with a normal ESR (<40 mm/hour) during a 6-month period were included in the study (case patients). Controls were 12 consecutive, untreated PMR outpatients with an ESR of >40 mm/hour who were observed after the case patients. Before starting corticosteroid therapy, all case patients and controls underwent bilateral shoulder ultrasonography (US) and magnetic resonance imaging (MRI). US and MRI scans were evaluated independently by two radiologists who were blinded to the reciprocal results. RESULTS: Six case patients (4 men and 2 women) and 12 controls (4 men and 8 women) were studied. Both US and MRI demonstrated bilateral subacromial/subdeltoid bursitis in all 6 case patients and in 11 of the 12 (92%) controls (P not significant [NS]). One control had unilateral bursitis. Glenohumeral joint synovitis was found in 4 of 6 case patients (67%) by MRI and in 3 of 6 case patients (50%) by US (P NS), as well as in 8 of 12 controls (67%) by MRI and in 7 of 12 controls (58%) by US (P NS). Both MRI and US detected biceps tenosynovitis in 5 of 6 case patients (83%) and in 8 of 12 controls (67%) (P NS). The severity of bursitis did not differ significantly between the groups. US was as effective as MRI in detecting inflammatory changes of the shoulder. CONCLUSION: MRI and US studies showed that PMR patients with normal or high ESRs have similar inflammatory shoulder lesions. Moreover, bilateral subacromial/subdeltoid bursitis represents the imaging hallmark in PMR patients with a high or normal ESR. MRI or US of the shoulder may facilitate the proper diagnosis in patients with the typical proximal symptoms of PMR who also have normal ESRs.

Shoulder ultrasonography in the diagnosis of polymyalgia rheumatica: a case-control study.

OBJECTIVE: Magnetic resonance imaging (MRI) showed that subacromial/subdeltoid bursitis is the most frequent shoulder lesion in polymyalgia rheumatica (PMR). We evaluated whether shoulder ultrasonography (US) was as effective as MRI in the detection of this lesion and assessed the sensitivity and specificity of bilateral subacromial/subdeltoid bursitis in the diagnosis of PMR. METHODS: A case-control study of 57 consecutive case patients with untreated PMR and 114 controls seen over a 6 month period in 3 secondary referral rheumatology centers. Control patients consisted of the next 2 consecutive patients with bilateral shoulder aching and stiffness observed after the case patient. In all case and control patients the glenohumeral joint space, bursae, and long head biceps tendon were assessed by bilateral shoulder US. The first 24 case patients were also examined by bilateral shoulder MRI. RESULTS: US showed subacromial/subdeltoid bursitis in 55/57 (96%) patients with PMR and in 25/114 (22%) controls (p < 0.001). The lesion was bilateral in 53/55 (96%) case patients and in 1/25 (4%) controls (p < 0.001). The frequency of glenohumeral joint synovitis and biceps tenosynovitis did not differ significantly between case patients and controls. In 100% of case patients MRI showed subacromial/subdeltoid bursitis confirming US findings. The sonographic evidence of bilateral bursitis had a sensitivity of 92.9%, specificity of 99. 1%, and positive predictive value of 98. 1% for the diagnosis of PMR. CONCLUSION: US and MRI were equally effective in confirming bilateral subacromial and subdeltoid bursitis in PMR. This finding, in view of its high sensitivity and specificity, could be used as a new diagnostic criterion for PMR.

Lung and chest wall mechanics in ventilated patients with end stage idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis is an inflammatory disease which leads to chronic ventilatory insufficiency and is characterised by a reduction in pulmonary static and dynamic volumes. It has been suggested that lung elastance may also be abnormally increased, particularly in end stage disease, but this has not been systematically tested. The aim of this study was to assess the respiratory mechanics during mechanical ventilation in patients affected by end stage disease. METHODS: Respiratory mechanics were monitored in seven patients with idiopathic pulmonary fibrosis being ventilated for acute respiratory failure (PaO2/FiO2 5.8 (0.3); pH 7. 28 (0.02); PaCO2 8.44 (0.82) kPa; tidal volume 3.4 (0.2) ml/kg; respiratory rate 35.1 (8.8) breaths/min) using an oesophageal balloon and airway occlusion during constant flow inflation. The total respiratory system mechanics (rs) was partitioned into lung (L) and chest wall (w) mechanics to measure static intrinsic positive end expiratory pressure (PEEPi), static (Est) and dynamic (Edyn) elastances, total respiratory resistance (Rrs), interrupter respiratory resistance (Rint,rs), and additional respiratory resistance (DeltaRrs). RESULTS: PEEPi was negligible in all patients. Edyn,rs and Est,rs were markedly increased (60.9 (7.3) and 51.9 (8. 0) cm H2O/l, respectively), and this was due to abnormal lung elastance (dynamic 53.9 (8.0) cm H2O/l, static 46.1 (8.1) cm H2O/l) while chest wall elastance was only slightly increased. Rrs and Rint, rs were also increased above the normal range (16.7 (4.5) and 13.7 (3.5) cm H2O/l/s, respectively). RL and Rint,L contributed 88% and 89%, on average, to the total. Edyn,rs, Est,rs, Rrs and Rint,rs were significantly correlated with the degree of hypercapnia (r = 0.64 (p<0.01), r = 0.54 (p<0.05), r = 0.84 (p<0.001), and r = 0.72 (p<0. 001), respectively). CONCLUSIONS: The elastances and resistances of the respiratory system are significantly altered in ventilated patients with end stage idiopathic pulmonary fibrosis. These features are almost totally due to abnormalities in lung mechanics. These profound alterations in elastic and resistive mechanical properties at this stage of the disease may be responsible for the onset of hypercapnia.

Noninvasive mechanical ventilation in the weaning of patients with respiratory failure due to chronic obstructive pulmonary disease. A randomized, controlled trial.

BACKGROUND: In patients with acute exacerbations of chronic obstructive pulmonary disease, mechanical ventilation is often needed. The rate of weaning failure is high in these patients, and prolonged mechanical ventilation increases intubation-associated complications. OBJECTIVE: To determine whether noninvasive ventilation improves the outcome of weaning from invasive mechanical ventilation. DESIGN: Multicenter, randomized trial. SETTING: Three respiratory intensive care units. PATIENTS: Intubated patients with chronic obstructive pulmonary disease and acute hypercapnic respiratory failure. INTERVENTION: A T-piece weaning trial was attempted 48 hours after intubation. If this failed, two methods of weaning were compared: 1) extubation and application of noninvasive pressure support ventilation by face mask and 2) invasive pressure support ventilation by an endotracheal tube. MEASUREMENTS: Arterial blood gases, duration of mechanical ventilation, time in the intensive care unit, occurrence of nosocomial pneumonia, and survival at 60 days. RESULTS: At admission, all patients had severe hypercapnic respiratory failure (mean pH, 7.18+/-0.06; mean PaCO2, 94.2+/-24.2 mm Hg), sensory impairment, and similar clinical characteristics. At 60 days, 22 of 25 patients (88%) who were ventilated noninvasively were successfully weaned compared with 17 of 25 patients (68%) who were ventilated invasively. The mean duration of mechanical ventilation was 16.6+/-11.8 days for the invasive ventilation group and 10.2+/-6.8 days for the noninvasive ventilation group (P = 0.021). Among patients who received noninvasive ventilation, the probability of survival and weaning during ventilation was higher (P = 0.002) and time in the intensive care unit was shorter (15.1+/-5.4 days compared with 24.0+/-13.7 days for patients who received invasive ventilation; P = 0.005). Survival rates at 60 days differed (92% for patients who received noninvasive ventilation and 72% for patients who received invasive ventilation; P = 0.009). None of the patients weaned noninvasively developed nosocomial pneumonia, whereas 7 patients weaned invasively did. CONCLUSIONS: Noninvasive pressure support ventilation during weaning reduces weaning time, shortens the time in the intensive care unit, decreases the incidence of nosocomial pneumonia, and improves 60-day survival rates.

[Factors determining the successful weaning of patients with "difficult weaning"]. / Fattori determinanti il successo dello svezzamento in pazienti con "svezzamento difficile".

OBJECTIVE: Weaning from mechanical ventilation is often possible in the most of patients, even if sometimes it is very difficult. For example, 25-53% of COPD patients cannot be weaned. The different modalities used do not justify this. The aim of the study was the evaluation of a further weaning trial in tracheotomized patients who underwent mechanical ventilation for at least 15 days in several ICU and in whom several attempts of weaning failed. DESIGN: A retrospective study (January 1993-February 1995). SETTING: Intermediate Intensive Respiratory Care Unit of Centro Medico Di Montescano. PATIENTS: Thirty-nine patients (29 male; 26 COPD, 3 post-surgery respiratory failure, 5 restrictive diseases, 4 with cardiovascular failure and 1 neurological disease) who had been tracheotomized and undergoing mechanical ventilation from at least 15 days. An initial evaluation in which respiratory mechanics and echocardiography were performed was made and then they underwent further weaning trials based on progressive decrease of the level of pressure support and periodic disconnection from MV and on medical therapy and strong physiokinesitherapy. RESULTS: Twenty-six out of 39 patients (66%) could reach definitive weaning (COPD 65%, post-surgery respiratory failure 66%, restrictive 60%, cardiovascular failure 100%, neurological disease 0%) after 17 days of average time of ventilation (range from 4 to 90). Among the important factors in determining a difficult or impossible weaning there are: a) previous wrong ventilation settings 8/26; b) cardiovascular problems 7/26; c) alterations in respiratory mechanics 2/26; d) previous excessive sedation 2/26; e) uncorrect timing of disconnection 2/26; f) poor physiokinesitherapy 2/26; g) unknown causes 3/26. Also the ICU from which the patients has been transferred plays an important role. CONCLUSIONS: The conclusion is drawn weaning from mechanical ventilation can be reached also in a part of those patients who are thought not weanable with a further, prolonged and expensive weaning trial.

Human and financial costs of noninvasive mechanical ventilation in patients affected by COPD and acute respiratory failure.

STUDY OBJECTIVES: It has been suggested that noninvasive mechanical ventilation (NIMV) may be a time-consuming procedure for medical and paramedical personnel. We carried out a prospective trial in 10 consecutive COPD patients aimed at assessing the human and economic resources needed to ventilate patients by NIMV and we compared these with those needed by a group of six patients receiving invasive mechanical ventilation (InMV). DESIGN: The daily cost and the minutes spent by medical doctors (MDs), respiratory therapists (RTs), and nurses (Ns) were recorded during the first 48 h of ventilation in 10 patients during NIMV (group A) and in six who received InMV (group B) after an initial unsuccessful attempt with NIMV. In two subgroups of patients (five for group A and four for group B), the analysis was also performed, except for RTs, for the total length of mechanical ventilation. SETTING: A respiratory ICU. PATIENTS: At hospital admission, the two groups of COPD patients did not differ for blood gas values (PaCO2 = 88.2+/-9.8 mm Hg for group A vs 90.5+/-12.8 mm Hg for group B, and pH = 7.21+0.08 vs 7.20+0.08, respectively) or for clinical and neurologic status, but patients of group B had not tolerated NIMV. MEASUREMENTS AND RESULTS: The total time spent at the bedside in the first 6 h did not differ between group A and B (group A = 72.3 min [MD], 87.2 min [RT], and 178.8 min [N] vs 98.8 min [MD], 12.5 min [RT], and 197.6 min [N] for group B). In the following 42 h, a plateau was reached so that there was a significant reduction for both groups in the time of assistance given by Ns (p<0.001) but not by MDs or RTs. The total costs were also not different between the two groups ($806+/-73 [US dollars per day] vs $864+/-44 for group A and B, respectively). In the subgroups monitored for the entire period of ventilation, a significant reduction in the time of assistance, for both MDs and Ns, was observed after approximately the first half. CONCLUSIONS: We conclude that in the first 48 h of ventilation, daily NIMV is neither more expensive nor time-consuming and staff demanding than InMV. After the first few days of ventilation, NIMV was significantly less time-consuming than InMV, for MDs and Ns, so that medical and paramedical time expenditure seems not to be a major problem during NIMV.

Patient-ventilator interaction and inspiratory effort during pressure support ventilation in patients with different pathologies.

The aim of this study was to evaluate whether pressure support ventilation (PSV) requires different diaphragmatic efforts and patient-ventilator matching, according to the underlying disease. Four groups of patients requiring PSV were studied: Group A, recovering from an episode of acute respiratory failure due to adult respiratory distress syndrome (ARDS); Group B, with postsurgical complications; and two subsets of chronic obstructive pulmonary disease (COPD) patients, with "normal" static compliance of the respiratory system (Cst,rs) (Group C) or elevated Cst,rs (Group D). Ventilatory pattern, transdiaphragmatic pressure (Pdi), the pressure-time product of the diaphragm (PTPdi), static (PEEPi,stat) and dynamic intrinsic positive end-expiratory pressure (PEEPi,dyn), Cst,rs and resistance of the total respiratory system (Rrs) were recorded. The matching between patient and ventilator was analysed, recording the number of "ineffective efforts" (inspiratory efforts not efficient enough to trigger a new ventilator cycle, despite a positive deflection in Pdi). A satisfactory blood gas equilibrium arterial oxygen saturation (Sa,O2 > 93%, with a pH > 7.32) was obtained in the various groups with different levels of PSV. Minute ventilation was found to be significantly higher in Groups A and B, due to the longer expiratory time (tE) in the COPD groups. Group A (2 out of 7), Group B (3 out of 7), Group C (3 out of 5) patients showed sporadic "ineffective efforts". All Group D patients manifested continuous mismatching with the ventilator, so that the pressure-time product of the diaphragm per minute (PTPdi/min), reflecting the metabolic work of the diaphragm, was not different in the four groups. Tidal volume and the spontaneous inspiratory efforts were similar in the four groups, but the number of breaths delivered by the ventilator was significantly higher in Groups A and B. The application of different levels of pressure support ventilation in patients with acute respiratory failure due to different pathologies, led them to breathe with comparable pressure time product of the diaphragm. The majority of the patients showed mismatching with the ventilator, although this effect was more pronounced in the groups with chronic obstructive pulmonary disease.

The tension-time index of the diaphragm revisited in quadriplegic patients with diaphragm pacing.

The fatigue threshold of the human diaphragm, index of its endurance and fatigability, corresponds, during spontaneous breathing, to a tension-time index (TTdi = Pdi/Pdimax x T1/Ttot (i.e., the inspiratory time over the total breath duration) of 0.15 to 0.18. We studied three quadriplegic patients with diaphragm pacing in order to reassess this threshold in patients in whom the contribution of the other respiratory muscles is lacking. Transdiaphragmatic pressure (Pdi) was obtained from the difference between gastric (Pga) and esophageal (Pes) pressures while the electromyograms (EMG) of both hemidiaphragms were recorded with surface electrodes. Four runs at different TTdi were performed on different days in each subject, varying either the Pdi developed per breath, changing the frequency of stimulation, or the T1/Ttot. The time of fatigue was defined when Pdi decreased during the trials by 35% from baseline. No evidence of transmission fatigue (i.e., decline in action potential amplitude) was observed. The TTdi at which fatigue occurred in all the quadriplegic patients was around 0.10 to 0.12, well below the values previously described. After fatigue had occurred, the force recovery during the force-frequency curve was not complete after 2 h at low frequencies, whereas at high frequencies it was fully complete at 30 min. We conclude that when respiration is accomplished only by the diaphragm, without the contribution of the other respiratory muscles, the fatigue threshold is lower than previously reported.

Non-invasive mechanical ventilation in severe chronic obstructive lung disease and acute respiratory failure: short- and long-term prognosis.

OBJECTIVE: To evaluate the short- and long-term prognosis of patients with chronic obstructive lung disease (COLD) who had noninvasive mechanical ventilation (NMV) for acute respiratory failure (ARF). DESIGN: Retrospective study. SETTING: Two respiratory intermediate intensive care units. PATIENTS: Two groups of patients suffering from COLD and an ARF episode requiring mechanical ventilation. Group 1 (30 patients) was given NMV using face masks (aged 64 +/- 9 years; pH = 7.28 +/- 0.05; PaCO2 = 83 +/- 18 mmHg; PaO2/FIO2 = 141 +/- 61). Group 2 (27 patients) was composed of control patients (aged = 65 +/- 8 years; pH = 7.26 +/- 0.05; PaCO2 = 75 +/- 17 mmHg; PaO2/FIO2 = 167 +/- 41) given MV using endotracheal intubation (EI) when clinical and functional conditions had further deteriorated because the medical therapy failed and NMV was not available at the time. Causes of ARF were in group 1 and 2 respectively: pneumonia in 8 (27%) and 11 (41%), acute exacerbation of COLD in 19 (63%) and 14 (52%) and pulmonary embolism in 3 (10%) and 2 (7%) patients. MEASUREMENTS AND RESULTS: Success rate, mortality during stay in ICU (at 3 months and at 1 year), and the need for rehospitalization during the year following ARF were measured in this study. Group 1 showed a success rate of 74%, only 8/30 patients needing EI and conventional MV. In group 2, the weaning success was 74% (20/27 patients). The mortality for group 1 was 20% in IICU, 23% at 3 months and 30% at 1 year; and 26% for group 2 in ICU, 48% at 3 months and 63% at 1 year. Within each group 1-year mortality was greater (p < 0.01) in patients with pneumonia. The number of new ICU admissions during the follow-up at 1 year was 0.12 versus 0.30 in groups 1 and 2 respectively (p < 0.05). CONCLUSION: For patients suffering from COLD who have undergone ARF, avoiding EI by early treatment with NMV is associated with better survival in comparison to patients bound to invasive MV. Pneumonia as a cause of ARF may worsen the prognosis in both groups of patients.

Respiratory response and inspiratory effort during pressure support ventilation in COPD patients.

OBJECTIVE: Pressure Support Ventilation (PSV) is now widely used in the process of weaning patients from mechanical ventilation. The aim of this study was to evaluate the effects of various levels of PS on respiratory pattern and diaphragmatic efforts in patients affected by chronic obstructive pulmonary disease (COPD). SETTING: Intermediate intensive care unit. PATIENTS: We studied ten patients undergoing PSV and recovering from an episode of acute respiratory failure due to exacerbation of COPD. METHODS: Three levels of PSV were studied, starting from the lowest (PSb) one at which it was possible to obtain an adequate Vt with a pH > or = 7.32 and an SaO2 > 93%. Then, PS was set at 5 cmH2O above (PSb + 5) and below (PSb-5) this starting level. Ventilatory pattern, transdiaphragmatic pressure (Pdi), the pressure-time product of the diaphragm (PTPdi), the integrated EMG of the diaphragm, static PEEP (PEEPi, stat), dynamic PEEP (PEEPi, dyn), and the static compliance and resistance of the total respiratory system were recorded. RESULTS: Minute ventilation did not significantly change with variations in the level of PS, while Vt significantly increased with PS (PS-5 = 6.3 +/- 0.5 ml/kg vs. PSb = 10.1 +/- 0.9 [p < 0.01] and vs. PS + 5 = 11.7 +/- 0.6 [p < 0.01]), producing a reduction in respiratory frequency with longer expiratory time. The best values of blood gases were obtained at PSb, while at PSb-5, PaCO2 markedly increased. During PSb and PSb + 5 and to a lesser extent during PSb-5, most of the patients made several inspiratory efforts that were not efficient enough to trigger the ventilator to inspire; thus, the PTPdi "wasted" during these inefficient efforts was increased, especially during PS + 5. The application of an external PEEP (PEEPe) of 75% of the static intrinsic PEEP during PSb caused a significant reduction in the occurrence of these inefficient efforts (p < 0.05). Minute ventilation remained constant, but Vt decreased, together with Te, leaving the blood gases unaltered. The PTPdi per breath and the dynamic PEEPi were also significantly reduced (by 59% and 31% of control, respectively, p < 0.001) with the application of PEEPe. CONCLUSION: We conclude that in COPD patients, different levels of PSV may induce different respiratory patterns and gas exchange. PS levels capable of obtaining a satisfactory equilibrium in blood gases may result in ineffective respiratory efforts if external PEEP is not applied. The addition of PEEPe, not exceeding dynamic intrinsic PEEP, may also reduce the metabolic work of the diaphragm without altering gas exchange.

Non-invasive mechanical ventilation in acute respiratory failure due to chronic obstructive pulmonary disease: correlates for success.

BACKGROUND: Non-invasive mechanical ventilation is increasingly used in the treatment of acute respiratory failure in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to identify simple parameters to predict the success of this technique. METHODS: Fifty nine episodes of acute respiratory failure in 47 patients with COPD treated with non-invasive mechanical ventilation were analysed, considering each one as successful (78%) or unsuccessful (22%) according to survival and to the need for endotracheal intubation. RESULTS: Pneumonia was the cause of acute respiratory failure in 38% of the unsuccessful episodes but only in 9% of the successful ones. Success with non-invasive mechanical ventilation was associated with less severely abnormal baseline clinical and functional parameters, and with less severe levels of acidosis assessed during an initial trial of non-invasive mechanical ventilation. CONCLUSIONS: The severity of the episode of acute respiratory failure as assessed by clinical and functional compromise, and the level of acidosis and hypercapnia during an initial trial of non-invasive mechanical ventilation, have an influence on the likelihood for success with non-invasive mechanical ventilation and may prove to be useful in deciding whether to continue with this treatment.

Elevated static compliance of the total respiratory system: early predictor of weaning unsuccess in severed COPD patients mechanically ventilated.

OBJECTIVE: To assess in a group of COPD patients mechanically ventilated for an episode of acute respiratory failure the respiratory mechanics with a simple and non invasive method at the bedside in order to evaluate if these parameters may be predictive of weaning failure or success. DESIGN: A prospective study. SETTING: Intensive care and intermediate intensive care units. PATIENTS: 23 COPD patients ventilated for acute respiratory failure and studied within 24 hours from intubation. METHODS: Using end-expiratory and end-inspiratory airway occlusion technique, we measured PEEPi, static compliance of the respiratory system (Crs, st) maximum respiratory resistance (Rrsmax) and minimum respiratory resistance (Rrsmin). MEASUREMENTS AND RESULTS: The weaned group (A) and the not weaned group (B) were not different regarding to static PEEPi (group A 8.5 +/- 4.0 vs group B 8.9 +/- 2.6 cmH2O), TO Rrsmax (22.4 +/- 5.3 versus 22.2 +/- 9.0 cmH2O/1/s) and to Rrsmin (17.6 +/- 5.5 versus 17.9 +/- 8.0 cmH2O/1/s), while a significant difference (p < 0.001) has been found in Cst, rs (62.7 +/- 17.% versus 111.6 +/- 18.0 ml/cm H2O). The threshold value of 88.5 ml/cmH2O was identified by discriminant analysis and provided the best separation between the two groups, with a sensitivity of 0.85 and a specificity of 0.87. CONCLUSION: Cst, rs measured non invasively in the first 24 h from intubation, provided a good separation between the patients who were successfully weaned and those who failed.

Ventilatory techniques during weaning.

Ventilatory techniques are only a part of the weaning process, that also includes medical therapy, physiokinesitherapy, nutrition, psychological support and nursing. Traditional ventilatory techniques used in weaning are: T-piece trials (alternated with assist-control ventilation (ACV)), pressure support ventilation (PSV), intermittent mandatory ventilation (IMV) and continuous positive airway pressure (CPAP) ventilation. None of these techniques has been demonstrated to be better than the others, and the physician must be prepared--to try alternate strategies according to the kind of patient. Noninvasive mechanical ventilation (NIMV) can be successfully used in weaning from invasive mechanical ventilation. Furthermore, NIMV by nasal or facial mask has been successfully used in the treatment of acute respiratory failure (ARF) due to various pathologies. In these cases, the weaning trial has an immediate beginning, since noninvasive ventilation is performed alternatively with spontaneous breathing after the early phase of ARF.

Weaning and outcome from mechanical ventilation.

Weaning means the ability of a patient to breath spontaneously after mechanical ventilation. In chronic obstructive pulmonary disease (COPD) patients, inability to tolerate discontinuation of mechanical ventilation is reported to have an incidence of 25-60%. It is, therefore, important to employ simple parameters able to predict weaning success, since, in the case of failure, the validation of predictive indices of weaning may also contribute to the decision of whether or not these patients should eventually enter a programme of home ventilation. Among other indices employed, respiratory frequency/tidal volume (f/VT) ratio, compliance, rate, oxygenation and pressure (CROP) index, mouth occlusion pressure (P0.1) and static compliance of the respiratory system have been shown to be quite accurate. The survival at one year of these patients requiring mechanical ventilation ranges 34-49%. Indeed, there is a particular subset of COPD patients in whom mechanical ventilation is prolonged due to the severity of their pathology. We studied 42 of these patients requiring mechanical ventilation for more than 21 days, to assess with simple parameters (arterial blood gases, pulmonary function tests, respiratory muscle force, P0.1, nutritional status) their potential for weaning and their survival at 2 yrs. Using discriminant analysis, and employing an equation comprising maximal inspiratory pressure (MIP) and arterial carbon dioxide tension (PaCO2), we were able to predict the patients able or unable to be weaned with an accuracy of almost 85%.(ABSTRACT TRUNCATED AT 250 WORDS)

Survival and prediction of successful ventilator weaning in COPD patients requiring mechanical ventilation for more than 21 days.

We studied survival and failure or success of weaning from mechanical ventilation (MV) in 42 consecutive chronic obstructive pulmonary disease (COPD) patients requiring prolonged MV (more than 21 days) after an episode of acute respiratory failure requiring admission to our Intermediate Intensive Care Unit (IICU). Parameters including arterial blood gases, pulmonary function tests, respiratory muscle force, neuromuscular drive, and nutritional status were recorded during a phase of clinical stability, in order to identify the features related to survival and weaning. All the patients were submitted to a comprehensive rehabilitation programme. Successful weaning from MV was defined as complete respiratory autonomy for at least 48 h. Twenty three patients were successfully weaned from MV after an average period of 44 days (Group A), requiring no further MV during their stay in hospital, whilst the remaining 19 patients were not able to be disconnected from the ventilator (Group B). The discriminant analysis showed that weaning from MV was significantly associated with arterial carbon dioxide tension (PaCO2), neuromuscular drive (P0.1), maximal inspiratory pressure (MIP), arterial oxygen tension (PaO2), the ratio of respiratory frequency to tidal volume (f/VT) and the serum protein level. Other pulmonary function tests (forced expiratory volume in one second (FEV1), FEV1/forced vital capacity (FVC), anthropometric data, nutritional status, number of pulmonary exacerbations during MV and evidence of cor pulmonale, were similar in the two groups. The discriminant equation considering PaCO2 and MIP could separate the two groups with an accuracy of 84%. The overall survival at 2 yrs was 40%; in Group B it was significantly lower than in Group A (22 vs 68%). Most of the deaths occurred within the first 120 days after intubation.(ABSTRACT TRUNCATED AT 250 WORDS)

Noninvasive mechanical ventilation in the treatment of acute respiratory failure due to infectious complications of lung transplantation.

Patients that have undergone lung and heart-lung transplantation may contract severe respiratory infections, often leading to acute respiratory failure requiring mechanical ventilation. Endotracheal intubation may induce infectious complications of the respiratory tract, which can be avoided by noninvasive modes of ventilation. We describe the use of noninvasive modes of ventilation in three cases of acute respiratory failure induced by infectious complication of lung and heart-lung transplantation. In two cases endotracheal intubation was avoided and treatment was successful.

[Nasal pressure support ventilation (NPSV) in a case of Pneumocystis carinii pneumonia in single-lung transplantation]. / Pressure support per via nasale (NPSV) in un caso di polmonite da Pneumocystis carinii in trapianto monopolmone.

In patients who underwent lung transplantation one of the primary determinants of patient survival is infection. Contributing factors in the development of pneumonia include immunosuppression and alterations in the natural lung defense mechanism induced by transplantation. We describe a case of a Pneumocystis carinii pneumonia occurring in the recipient of single lung transplantation for interstitial lung disease four months after surgery. The patient developed severe acute respiratory failure (ARF) requiring mechanical ventilation. Because of the increased infectious risk, tracheal intubation was avoided and pressure support ventilation was performed by the nasal route (NPSV) with PEEP (PS: 16 cm H2O PEEP: 8 cm H2O). NPSV and PEEP were applied 20-22 hours/day in the first 4 days, thereafter 2 to 6 hours 3 times a day, together with medical therapy. This treatment was performed for 15 days. This mode of ventilation was well tolerated and was successful. We conclude that NPSV may be useful in the treatment of ARF in patients with lung transplantation, particularly to avoid invasive mechanical ventilation related infectious complications.

Acute effect of corticosteroids on respiratory mechanics in mechanically ventilated patients with chronic airflow obstruction and acute respiratory failure.

We assessed the short-term effect of steroids on respiratory mechanics in eight mechanically ventilated patients with chronic airflow obstruction (CAO) and hypercapnic respiratory failure. Airflow (V), airway pressure (Paw), and changes in pulmonary volume were measured using a conventional ventilator. End-expiratory and end-inspiratory airway occlusions were performed to assess intrinsic PEEP (PEEPi), static compliance of total respiratory system (Cstrs), maximum inspiratory resistance (Rrsmax), and minimum inspiratory resistance (Rrsmin). These parameters were recorded at control, 30 min after saline, and 90 min after steroid (methylprednisolone 0.8 mg/kg intravenous) administration. No significant changes were found in respiratory mechanics after administration of saline. Steroids induced a significant decrease (p < 0.01) in inspiratory resistance (Rrsmax from 20.3 +/- 8.6 cm H2O/L/s (control) to 15.3 +/- 6.1 (90 min) and Rrsmin from 16.2 +/- 8.0 (control) to 11.9 +/- 6.5 (90 min), with no significant reduction in Paw and Cstrs. The PEEPi, reflecting pulmonary dynamic hyperinflation, was also significantly reduced (-16% from control). We conclude that in mechanically ventilated CAO patients, steroids may be useful in improving respiratory mechanics and therefore in providing better conditions for weaning from mechanical ventilation.