Measuring the equations of state in a relaxed magnetohydrodynamic plasma.

We report measurements of the equations of state of a fully relaxed magnetohydrodynamic (MHD) laboratory plasma. Parcels of magnetized plasma, called Taylor states, are formed in a coaxial magnetized plasma gun, and are allowed to relax and drift into a closed flux conserving volume. Density, ion temperature, and magnetic field are measured as a function of time as the Taylor states compress and heat. The theoretically predicted MHD and double adiabatic equations of state are compared to experimental measurements. We find that the MHD equation of state is inconsistent with our data.

Last 3 months of life in home-ventilated patients: the family perception.

We studied the family's perception of care in patients under home mechanical ventilation during the last 3 months of life. In 11 respiratory units, we submitted a 35-item questionnaire to relatives of 168 deceased patients exploring six domains: symptoms, awareness of disease, family burden, dying, medical and technical problems. Response rate was 98.8%. The majority of patients complained respiratory symptoms and were aware of the severity and prognosis of the disease. Family burden was high especially in relation to money need. During hospitalisation, 74.4% of patients were admitted to the intensive care unit (ICU). 78 patients died at home, 70 patients in a medical ward and 20 in ICU. 27% of patients received resuscitation manoeuvres. Hospitalisations and family economical burden were unrelated to diagnosis and mechanical ventilation. Families of the patients did not report major technical problems on the use of ventilators. In comparison with mechanical invasively ventilated patients, noninvasively ventilated patients were more aware of prognosis, used more respiratory drugs, changed ventilation time more frequently and died less frequently when under mechanical ventilation. We have presented good points and bad points regarding end-of-life care in home mechanically ventilated patients. Noninvasive ventilation use and diagnosis have impact on this burden.

Episodic medical home interventions in severe bedridden chronic respiratory failure patients: a 4 year retrospective study.

BACKGROUND AND AIM: Home care for respiratory patients includes a complex array of services delivered in an uncontrolled setting. The role of a respiratory specialist inside the home healthcare team has been scarcely studied up to now. Our aims were to analyse the number and quality of episodic home visits performed by respiratory physicians to severe bedridden Chronic Respiratory Failure (CRF) patients, and also to evaluate the safety of tracheotomy tube substitutions at home. METHODS: 231 home interventions (59.8/year) in 123 CRF patients (59 males; age 63 +/- 17 y, 24 on oxygen therapy, 35 under non invasive mechanical ventilation, 46 under invasive ventilation, 74 with tracheostomy) located 35 +/- 16 km far from referred hospital, were revised in a period of 4 years (2005-2008). RESULTS: Chronic Obstructive Pulmonary Disease (COPD) (31%) and amyotrophic lateral sclerosis (ALS) (28%) were the more frequent diagnoses. Interventions were: tracheotomy tube substitution (64%) presenting 22% of minor adverse events and 1.4% of major adverse events; change or new oxygen prescription (37%); nocturnal pulsed saturimetric trend prescription (24%); change in mechanical ventilation (MV) setting (4%); new MV adaptation (7%). After medical intervention, new home medical equipment devices (oxygen and MV) were prescribed in 36% of the cases while rehabilitative hospital admission and home respiratory physiotherapy prescription was proposed in 9% and 6% of the cases respectively. Patient/caregiver's satisfaction was reported on average 8.48 +/- 0.79 (1 = the worst; 10 = the higher). The local health care system (HCS) reimbursed 70 euros for each home intervention. Families saved 42 +/- 20 euros per visit for ambulance transportation. CONCLUSIONS: Home visits performed by a respiratory physician to bedridden patients with chronic respiratory failure: 1. include predominantly patients affected by COPD and ALS; 2. determine a very good satisfaction to patients/caregivers; 3. allow money saving to caregivers; 4. are predominantly made up to change tracheotomy tube without severe adverse events.

Home mechanical ventilation patients: a retrospective survey to identify level of burden in real life.

BACKGROUND AND AIM: Home care for patients under home mechanical ventilation (HMV) may cause dramatic physical and economic burden in addition to the burden of time on family/caregivers and health care service (HCS) with difficult resource allocation decision-making. Our aims were: 1. To identify conditions causing major care burden in managing HMV patients according to family and payer's perspectives related to characteristics of the disease, dependency and accessibility; and 2. To find, if any, differences among diseases. METHODS: A questionnaire was sent to eight pulmonary centres to identify factors connected with the greater care burden. Retrospective data of 792 patients still alive and in HMV was reviewed. RESULTS: Compared to neuromuscular disorders (NM) and chest wall deformities, the COPD group have presented a statistically greater number of hospitalisations/yr (1.37 +/- 0.77), greater length of stay (13 +/- 10 days), higher number of outpatient visits/yr (2.55 +/- 1.73) or emergency room accesses/yr (0.74 +/- 1.08). Patients with NM diseases need more home care. The prevalence of one, two and three among five selected burden criteria (needs of MV > 12 hrs/day, tracheotomy, high dependency, distance from hospital, frequent hospitalisations) was respectively 19%, 30% and 33% of the cases; the NM was the group most represented. CONCLUSIONS: In HMV patients: 1. underlying disease, level of their dependency, hours spent under MV, presence of tracheotomy, home distance from hospital, hospital accesses are the causes of major care burden; and 2. as a novelty we have demonstrated that more than fifty percent of them present two or three contemporaneous criteria selected as care burden, being NM and COPD patients the most representative group necessitating of family's and HCS's care respectively.

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.

Histochemical and immunohistochemical evidence of a bacterium associated with lesions of epizootic bovine abortion.

Epizootic bovine abortion (EBA), a tick-transmitted disease of pregnant cattle grazing foothill pastures, is a major cause of reproductive failure in California and adjacent states. Affected fetuses develop a chronic disease, resulting in late-term abortion or premature calving. Despite investigations spanning 50 years, to the authors' knowledge, the etiologic agent of EBA has not yet been isolated from affected fetuses or the tick vector. The diagnosis of EBA is based on gross and microscopic lesions. Recently, documentation that the etiologic agent is susceptible to antibiotics and identification of a unique 16S deltaproteobacterial rDNA gene sequence in 90% of thymus tissues from aborted fetuses have supported the role of a bacterial infection as the cause of EBA. To determine whether bacteria could be detected in the tissues, histochemical staining and immunohistochemical procedures were used on formalin-fixed, paraffin-embedded tissues. Use of a modified Steiner silver stain revealed small numbers of intracytoplasmic bacterial rods in 37 of 42 thymic samples from EBA-affected fetuses. Improved detection was achieved by use of immunohistochemical staining with serum from EBA-affected fetuses that resulted in detection of numerous bacterial rods in the cytoplasm of histiocytic cells in the thymus from all 42 EBA-affected fetuses. Immunohistochemical examination of additional tissues from 21 field and experimental EBA cases revealed positively stained intracytoplasmic bacterial rods in many organs with inflammatory lesions. Use of the modified Steiner stain and immunohistochemical staining of tissues from negative-control fetuses failed to reveal organisms. To the authors' knowledge, this is the first report to document morphologic evidence of a bacterium associated with the lesions of EBA.

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.

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.

Immunohistochemical identification of Campylobacter fetus in natural cases of bovine and ovine abortions.

An immunohistochemistry (IHC) procedure for the detection of Campylobacter fetus antigens using an avidin-biotin complex technique was performed on formalin fixed bovine and ovine fetal tissues from 26 natural cases of Campylobacter spp. abortion (four ovine and 22 bovine). The species of Campylobacter isolated included C. fetus ssp. venerealis from 13 bovine fetuses, C. fetus ssp. fetus from two ovine and one bovine fetus, Campylobacter jejuni from seven bovine fetuses, Campylobacter lari from two ovine fetuses and an unspeciated Campylobacter species in one bovine fetus. Histologic lesions identified in the aborted fetuses included placentitis, serositis, pneumonia, gastroenteritis, hepatitis and encephalitis. Campylobacter fetus antigens were identified by IHC in 13 of 13 bovine fetuses from which C. fetus ssp. venerealis was isolated and in two of two ovine fetuses from which C. fetus ssp. fetus was isolated. The IHC stains were negative in tissues from seven bovine fetuses from which C. jejuni was isolated, one bovine fetus infected with C. fetus ssp. fetus, one bovine fetus infected with the unspeciated Campylobacter and two ovine fetuses infected with C. lari. In positive cases, the IHC stain most frequently identified bacteria in the lung and gastrointestinal tract. The C. fetus IHC procedure performed on formalin fixed tissues is a practical tool for the diagnosis of natural cases of ovine and bovine abortion caused by C. fetus.

Inspiratory muscle workload due to dynamic intrinsic PEEP in stable COPD patients: effects of two different settings of non-invasive pressure-support ventilation.

BACKGROUND: In severe stable hypercapnic COPD patients the amount of pressure time product (PTP) spent to counterbalance their dynamic intrinsic positive end expiratory pressure (PEEPi,dyn) is high: no data are available on the best setting of non invasive pressure support ventilation (NPSV) to reduce the inspiratory muscle workload due to PEEPi,dyn. METHODS: The objectives of this randomised controlled physiological study were: 1. To measure the inspiratory muscle workload due to PEEPi,dyn 2. To measure the effects on this parameter of two settings of NPSV in stable COPD patients with chronic hypercapnia admitted in a Pulmonary Division of two Rehabilitation Centers. Twenty-three stable COPD patients with chronic hypercapnia on domiciliary nocturnal NPSV for 30 +/- 20 months were submitted to an evaluation of breathing pattern, PEEPi,dyn, inspiratory muscle workload and its partitioning during both assisted and unassisted ventilation. Two settings of NPSV were randomly applied for 30 minutes each: i- "at patient's comfort" (C): Inspiratory pressure support (IPS) was the maximal tolerated pressure able to reduce awake PaCO2 with the addition of a pre-set level of external PEEP (PEEPe); ii- "physiological setting" (PH): the level of IPS able to achieve a > 40% and < 90% decrease in transdiaphragmatic pressure in comparison to spontaneous breathing (SB). A PEEPe level able to reduce PEEPi,dyn by at least 50% was added. RESULTS: During SB the tidal diaphragmatic pressure-time product (PTPdi/b) was 17.62 +/- 7.22 cmH2O*sec, the component due to PEEPi,dyn (PTPdiPEEPi,dyn) being 38 +/- 17% (range: 16-65%). Compared to SB,PTPdiPEEPi,dyn was reduced significantly with both settings, the reduction being greater with PH compared to C. CONCLUSIONS: In conclusion in severe COPD patients with chronic hypercapnia the inspiratory muscle workload due to PEEPidyn is high and is reduced by NPSV at a greater extent when ventilator setting is tailored to patient's mechanics.

Effects of inhaled steroids on methacholine-induced bronchoconstriction and gas trapping in mild asthma.

According to a recent hypothesis, airway smooth muscle regulates airway calibre mostly at high lung volume, whereas the mucosa and adventitia dimensions dominate at low lung volumes. It was thought that if inhaled steroids decrease the thickness of airway wall in asthma, then forced vital capacity (FVC), which reflects the functional changes at low lung volume, should decrease less during induced bronchoconstriction than flow at high volume. The study was conducted in 31 mild asthmatics under control conditions and during a methacholine challenge before and after 4-weeks treatment with inhaled fluticasone dipropionate (1.5 mg daily, 16 patients) or placebo (15 patients). After fluticasone dipropionate treatment, control forced expiratory volume in one second (FEV1), and maximal flow at 50% of control FVC during forced expiration after a maximal (V'max,50) and a partial inspiration (V'p,50) significantly increased. During methacholine challenge, FVC decreased less than did FEV1 or V'max,50, and so did inspiratory vital capacity compared to V'p,50. Both the provocative dose of methacholine causing a 20% fall in FEV1 and the bronchodilator effect of deep inhalation significantly increased. The latter was assessed by means of the regression coefficient of all V'max,50 plotted against V'p,50. No significant changes in these parameters occurred after placebo. These data show that inhaled steroids remarkably blunt the occurrence of gas trapping during induced bronchoconstriction in mild bronchial asthma, possibly due to their effect on airway wall remodelling.

Prediction of FEV1 reductions in patients undergoing pulmonary resection.

In the assessment of functional operability of lung cancer the simple calculation of predicted postoperative forced expiratory volume in one second (ppoFEV1) based on the number of the bronchopulmonary segments removed, has recently been found to underestimate the actual postoperative forced expiratory volume in one second (FEV1). We checked whether this could be accounted for by lesions causing uneven ventilation or perfusion. We performed a retrospective study of 12 patients with atelectasis, hilar disease or endobronchial involvement (Group A) versus 24 patients with peripheral lung cancer (Group B). Baseline and postoperative FEV1 were measured and ppoFEV1 and ppoFEV1/actual postoperative FEV1 were calculated. In all subjects in Group A ppoFEV1 grossly underestimated the measured postoperative FEV1 (mean (SD) ratio between the two parameters: 67.0 (12.1)%). In Group B, ppoFEV1 was almost identical to the measured value in all but three patients, in whom it only slightly underestimated the actual postoperative value (mean ratio between the two parameters: 94.9 (12.6) %). In conclusion, predicted postoperative forced expiratory volume in one second is useful in the preoperative assessment of patients undergoing lung resection for lesions other than those causing uneven ventilation or perfusion. When this condition is suspected, before declaring a given case ineligible for surgery or at high risk of complications, more sophisticated procedures, such as radionuclide perfusion studies, should be performed.