The effects of real-time waveform analysis software on patient ventilator synchronization during pressure support ventilation: a randomized crossover physiological study

BACKGROUND

Patient-ventilator asynchrony commonly occurs during pressure support ventilation (PSV). IntelliSync + software (Hamilton Medical AG, Bonaduz, Switzerland) is a new ventilation technology that continuously analyzes ventilator waveforms to detect the beginning and end of patient inspiration in real time. This study aimed to evaluate the physiological effect of IntelliSync + software on inspiratory trigger delay time, delta airway (Paw) and esophageal (Pes) pressure drop during the trigger phase, airway occlusion pressure at 0.1 s (P0.1), and hemodynamic variables.

METHODS

A randomized crossover physiologic study was conducted in 14 mechanically ventilated patients under PSV. Patients were randomly assigned to receive conventional flow trigger and cycling, inspiratory trigger synchronization (I-sync), cycle synchronization (C-sync), and inspiratory trigger and cycle synchronization (I/C-sync) for 15 min at each step. Other ventilator settings were kept constant. Paw, Pes, airflow, P0.1, respiratory rate, SpO2, and hemodynamic variables were recorded. The primary outcome was inspiratory trigger and cycle delay time between each intervention. Secondary outcomes were delta Paw and Pes drop during the trigger phase, P0.1, SpO2, and hemodynamic variables.

RESULTS

The time to initiate the trigger was significantly shorter with I-sync compared to baseline (208.9±91.7 vs. 301.4±131.7 msec; P = 0.002) and I/C-sync compared to baseline (222.8±94.0 vs. 301.4±131.7 msec; P = 0.005). The I/C-sync group had significantly lower delta Paw and Pes drop during the trigger phase compared to C-sync group (-0.7±0.4 vs. -1.2±0.8 cmH2O; P = 0.028 and - 1.8±2.2 vs. -2.8±3.2 cmH2O; P = 0.011, respectively). No statistically significant differences were found in cycle delay time, P0.1 and other physiological variables between the groups.

CONCLUSIONS

IntelliSync + software reduced inspiratory trigger delay time compared to the conventional flow trigger system during PSV mode. However, no significant improvements in cycle delay time and other physiological variables were observed with IntelliSync + software.

TRIAL REGISTRATION

This study was registered in the Thai Clinical Trial Registry (TCTR20200528003; date of registration 28/05/2020).

Bronchodilator Efficacy of High-Flow Nasal Cannula in COPD: Vibrating Mesh Nebulizer Versus Jet Nebulizer

BACKGROUND

Jet nebulizers are commonly used for bronchodilator therapy in COPD. High-flow nasal cannula with vibrating mesh nebulizer (HFNC-VMN) is a recently developed system; however, few studies have compared the efficacy of bronchodilator administration via HFNC-VMN to jet nebulizer in stable COPD. This study aimed to compare the effect of salbutamol administered via HFNC-VMN versus jet nebulizer on airway and lung function in subjects with stable COPD.

METHODS

This randomized non-inferiority crossover physiologic study enrolled subjects with stable COPD. Salbutamol was nebulized via HFNC-VMN or jet nebulizer in random order with a 4-h washout period between crossover sequences. Spirometry, lung volume, and impulse oscillometry were performed at baseline and after each intervention. The primary outcome was change in FEV1 from baseline. Secondary outcomes included changes in other respiratory-related parameters and nebulization time compared between the 2 devices.

RESULTS

Seventeen subjects were enrolled. HFNC-VMN and jet nebulizer both significantly improved FEV1 from baseline (P = .005 and P = .002, respectively). The difference between respiratory resistance at 5 Hz and 20 Hz significantly decreased after HFNC-VMN compared to baseline (P = .02), while no significant change was observed after jet nebulizer (P = .056). Area of reactance and resonant frequency of reactance were both significantly decreased (P = .035 and P = .03, respectively), and respiratory reactance at 5 Hz significantly increased (P = .02) in the HFNC-VMN group compared to baseline indicating improved lung mechanics, with no significant changes with the jet nebulizer. HFNC-VMN had a shorter nebulization time (6 [5-9] min vs 20 [16-22] min, respectively, P < .001).

CONCLUSIONS

Bronchodilator therapy via HFNC-VMN was not inferior to jet nebulizer for subjects with stable COPD and can significantly improve airway oscillometry mechanics and decrease nebulization time compared to jet nebulizer.

Safety and efficacy of noninvasive ventilation for acute respiratory failure in general medical ward: a prospective cohort study

Background

Noninvasive ventilation (NIV) is recommended for use in patients with acute respiratory failure of various etiologies. However, we do not know whether the use of NIV in general medical wards is safe and effective. This study aimed to evaluate the safety and efficacy of using NIV and factors associated with NIV failure in general medical wards.

Methods

A prospective cohort study was conducted in general medical wards of the University Hospital. Adult patients with acute respiratory failure treated with NIV were enrolled. The subjects were managed by a multidisciplinary care team that was well trained in the NIV device. The primary outcome was the rate of NIV failure at 48 hours. Secondary outcomes included hospital mortality and factors associated with NIV failure.

Results

A total of 86 patients were enrolled. The mean age was 70±17 years old. The Acute Physiology and Chronic Health Evaluation (APACHE) III and the Sequential Organ Failure Assessment (SOFA) scores were 56±17 and 4±3, respectively. The most common indication of NIV use was cardiogenic pulmonary edema (34.9%). The rate of NIV failure at 48 hours and hospital mortality were 20.9% and 12.8%, respectively. The SOFA score was associated with failure of NIV at 48 hours [odds ratio (OR) 1.48, 95% confidence interval (CI): 1.16-1.89; P=0.002].

Conclusions

NIV was safe and effective on general medical wards. Cardiogenic pulmonary edema was the most common indication for the application of NIV. The SOFA score was associated with the failure of NIV at 48 hours.

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

BACKGROUND

Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation.

METHODS

WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109.

FINDINGS

Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0-4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2-6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital.

INTERPRETATION

In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates.

FUNDING

European Society of Intensive Care Medicine, European Respiratory Society.

Comparison Study between Using Disposable and Non-Disposable Ventilator Circuits on Ventilator-Associated Pneumonia and Health Care Costs at a Respiratory Care Unit, Siriraj Hospital

Objective: This research aimed to compare the incidence of ventilator-associated pneumonia (VAP) and ventilator circuit costs among patients using disposable ventilator circuits and patients using non-disposable ventilator circuits. Materials and Methods: Observational research was performed consisting of the following: A retrospective chart review of a group of patients who used non-disposable circuits (n=193) and a prospective cohort study of a group of patients using disposable circuits (n=166). The sample was purposively selected based on the following inclusion criteria: patients aged 18 years old and over who were admitted to the Respiratory Care Unit, Siriraj Hospital and ventilated >48 h. Results: VAP incidence in the group non-disposable circuits was 10.41/1,000 ventilator days (n=27, 13.8%) and 10.82 /1,000 ventilator days (n=24, 14.4%) in the group disposable circuits (p=0.871). According to the data analysis using the U-control chart, no statistically significant differences were found. The unit cost of the non-disposable circuit was lower than that of the disposable circuit (THB 295.94), while the work unit personnel satisfaction toward working with disposable circuits was at a good level (Mean=3.83) and medium level (Mean=3.12) in non-disposable circuits (p=0.002). Conclusion: The type of ventilator circuits had no effects on VAP rate. The unit cost of non-disposable circuits was lower than that of disposable circuits, while the work unit personnel had a higher satisfaction working with disposable circuits than non-disposable circuits.

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background

Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies.

Methods

In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality.

Findings

Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42·4% vs 44·2%; absolute difference –1·69 [–9·58 to 6·11] p=0·67; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5–8] vs 6 [5–8] cm H₂O; p=0·0011). ICU mortality was higher in MICs than in HICs (30·5% vs 19·9%; p=0·0004; adjusted effect 16·41% [95% CI 9·52–23·52]; p<0·0001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0·80 [95% CI 0·75–0·86]; p<0·0001).

Interpretation

Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status.

Funding

No funding.

Number of attempts required by emergency physicians to achieve competency in diaphragmatic ultrasound imaging

PURPOSE

This research aimed to determine the number of attempts that emergency physicians need to become proficient in undertaking diaphragmatic ultrasound imaging.

METHODS

A prospective observational study was conducted at the emergency department (ED) of a tertiary-care university hospital. Sixteen emergency physicians were each required to obtain a set of images of the right hemidiaphragm of five dyspneic patients using both diaphragmatic excursion and thickness techniques. The images were subsequently reviewed by a specialist using American College of Emergency Physician guidelines. If the evaluations of a physician did not reach the expected standard, the physician was to be given feedback and requested to collect images from another five patients. The process was to be repeated until such time as the images obtained by the physician were deemed to be up to standard.

RESULTS

Eighty patients, twelve emergency medicine residents, and four attending physicians were enrolled. Following a didactic session on diaphragmatic ultrasound imaging and its interpretation, practicing on five patients proved sufficient to achieve an adequate level of competency in conducting diaphragmatic ultrasound examinations.

CONCLUSION

Practicing on five patients is sufficient for emergency physicians to achieve an adequate level of competency in conducting right-sided diaphragmatic ultrasound examinations.

Validation of rapid shallow breathing index displayed by the ventilator compared to the standard technique in patients with readiness for weaning

BACKGROUND

Rapid shallow breathing index (RSBI) is the most commonly used parameter for predicting weaning outcome. Measurement of RSBI by Wright spirometer (RSBI_standard) is the standard method in routine clinical practice. Data specific to the accuracy and reliability of the RSBI value displayed by the ventilator (RSBI_vent) are scarce. Accordingly, this study aimed to evaluate the association between the average value of RSBI_vent at different time points and RSBI_standard, and to assess the accuracy and reliability of these two RSBI measurement techniques.

METHODS

This prospective cohort study included mechanically ventilated patients who were ready to wean. At the beginning of spontaneous breathing trial using the flow-by method, RSBI was measured by two different techniques at the same time, including: (1) Wright spirometer (breathing frequency/average tidal volume in 1 min) (RSBI_standard), and (2) the values displayed on the ventilator at 0, 15, 30, 45, and 60 s (RSBI_vent).

RESULTS

Forty-seven patients were enrolled. The RSBI_vent value was significantly higher than the RSBI_standard value for every comparison. According to Spearman's correlation coefficient (r) and intraclass correlation coefficient (ICC), the average value of RSBI from 5 time points (0, 15, 30, 45, and 60 s) showed the best correlation with the standard technique (r = 0.76 [P < 0.001], and ICC = 0.79 [95% CI 0.61-0.88], respectively). Bland-Altman plot also showed the best agreement between RSBI_standard and the RSBI_vent value averaged among 5 time points (mean difference - 17.1 breaths/min/L).

CONCLUSIONS

We found that the ventilator significantly overestimates the RSBI value compared to the standard technique by Wright spirometer. The average RSBI_vent value among 5 time points (0, 15, 30, 45, and 60 s) was found to best correlate with RSBI_standard.

High-Flow Oxygen Therapy in Tracheostomized Subjects With Prolonged Mechanical Ventilation: A Randomized Crossover Physiologic Study

BACKGROUND

High-flow oxygen therapy via tracheostomy (HFT) can be used in tracheostomized patients during ventilator disconnection. The physiologic effects of this technique are unknown. We hypothesized that HFT would reduce inspiratory effort and improve breathing pattern compared to conventional oxygen therapy via T-tube. This study aimed to evaluate the physiologic effects of HFT compared to conventional O₂ in patients with prolonged mechanical ventilation.

METHODS

A randomized crossover physiologic study was conducted in adult tracheostomized patients who experienced temporary periods of ventilator disconnection. Subjects were ventilated with pressure support ventilation (PSV) for 15 min and were then randomly assigned to HFT or conventional O₂ via T-tube for 30 min. After a washout period, subjects were switched to the other system. Esophageal pressure (P_es), breathing frequency, blood pressure, heart rate, [Formula: see text], and transcutaneously measured pressure of carbon dioxide ([Formula: see text]) were recorded. The primary outcome was inspiratory effort as determined by the simplified esophageal pressure-time product (sPTP_es). Secondary outcomes were P_es swing, breathing frequency, heart rate, mean arterial pressure, [Formula: see text], and [Formula: see text] between groups.

RESULTS

Twenty-two subjects were enrolled: sPTP_es per minute was significantly higher with HFT and conventional O₂ compared to PSV (153.5 ± 97.9, 163.5 ± 111.3, and 86.8 ± 51.1 cm H₂O × s/min, respectively, P = .001), but it was not different between HFT and conventional O₂ (P = .72). Breathing frequency increased significantly after switching from PSV to HFT and conventional O₂ (23 ± 4 vs 26 ± 6 and 23 ± 4 vs 27 ± 5 breaths/min, respectively, P = .001). [Formula: see text] was higher with conventional O₂ compared to HFT (P = .02). No differences in [Formula: see text], mean arterial pressure, or heart rate were observed between HFT and conventional O₂.

CONCLUSIONS

Inspiratory effort and breathing frequency increased significantly during unassisted breathing compared to PSV in tracheostomized subjects, but HFT via tracheostomy provided no measurable additional physiologic benefit compared to O₂ therapy via T-tube.

Duration of diaphragmatic inactivity after endotracheal intubation of critically ill patients

BACKGROUND

In patients intubated for mechanical ventilation, prolonged diaphragm inactivity could lead to weakness and poor outcome. Time to resume a minimal diaphragm activity may be related to sedation practice and patient severity.

METHODS

Prospective observational study in critically ill patients. Diaphragm electrical activity (EAdi) was continuously recorded after intubation looking for resumption of a minimal level of diaphragm activity (beginning of the first 24 h period with median EAdi > 7 µV, a threshold based on literature and correlations with diaphragm thickening fraction). Recordings were collected until full spontaneous breathing, extubation, death or 120 h. A 1 h waveform recording was collected daily to identify reverse triggering.

RESULTS

Seventy-five patients were enrolled and 69 analyzed (mean age ± standard deviation 63 ± 16 years). Reasons for ventilation were respiratory (55%), hemodynamic (19%) and neurologic (20%). Eight catheter disconnections occurred. The median time for resumption of EAdi was 22 h (interquartile range 0-50 h); 35/69 (51%) of patients resumed activity within 24 h while 4 had no recovery after 5 days. Late recovery was associated with use of sedative agents, cumulative doses of propofol and fentanyl, controlled ventilation and age (older patients receiving less sedation). Severity of illness, oxygenation, renal and hepatic function, reason for intubation were not associated with EAdi resumption. At least 20% of patients initiated EAdi with reverse triggering.

CONCLUSION

Low levels of diaphragm electrical activity are common in the early course of mechanical ventilation: 50% of patients do not recover diaphragmatic activity within one day. Sedatives are the main factors accounting for this delay independently from lung or general severity. Trial Registration ClinicalTrials.gov (NCT02434016). Registered on April 27, 2015. First patients enrolled June 2015.

Use of nasal high flow oxygen during acute respiratory failure

Nasal high flow (NHF) has gained popularity among intensivists to manage patients with acute respiratory failure. An important literature has accompanied this evolution. In this review, an international panel of experts assessed potential benefits of NHF in different areas of acute respiratory failure management. Analyses of the physiological effects of NHF indicate flow-dependent improvement in various respiratory function parameters. These beneficial effects allow some patients with severe acute hypoxemic respiratory failure to avoid intubation and improve their outcome. They require close monitoring to not delay intubation. Such a delay may worsen outcome. The ROX index may help clinicians decide when to intubate. In immunocompromised patients, NHF reduces the need for intubation but does not impact mortality. Beneficial physiological effects of NHF have also been reported in patients with chronic respiratory failure, suggesting a possible indication in acute hypercapnic respiratory failure. When intubation is required, NHF can be used to pre-oxygenate patients either alone or in combination with non-invasive ventilation (NIV). Similarly, NHF reduces reintubation alone in low-risk patients and in combination with NIV in high-risk patients. NHF may be used in the emergency department in patients who would not be offered intubation and can be better tolerated than NIV.

Airway Occlusion Pressure As an Estimate of Respiratory Drive and Inspiratory Effort during Assisted Ventilation

Rationale: Monitoring and controlling respiratory drive and effort may help to minimize lung and diaphragm injury. Airway occlusion pressure (P0.1) is a noninvasive measure of respiratory drive.Objectives: To determine 1) the validity of "ventilator" P0.1 (P0.1vent) displayed on the screen as a measure of drive, 2) the ability of P0.1 to detect potentially injurious levels of effort, and 3) how P0.1vent displayed by different ventilators compares to a "reference" P0.1 (P0.1ref) measured from airway pressure recording during an occlusion.Methods: Analysis of three studies in patients, one in healthy subjects, under assisted ventilation, and a bench study with six ventilators. P0.1vent was validated against measures of drive (electrical activity of the diaphragm and muscular pressure over time) and P0.1ref. Performance of P0.1ref and P0.1vent to detect predefined potentially injurious effort was tested using derivation and validation datasets using esophageal pressure-time product as the reference standard.Measurements and Main Results: P0.1vent correlated well with measures of drive and with the esophageal pressure-time product (within-subjects R² = 0.8). P0.1ref >3.5 cm H₂O was 80% sensitive and 77% specific for detecting high effort (≥200 cm H₂O ⋅ s ⋅ min^-1); P0.1ref ≤1.0 cm H₂O was 100% sensitive and 92% specific for low effort (≤50 cm H₂O ⋅ s ⋅ min^-1). The area under the receiver operating characteristics curve for P0.1vent to detect potentially high and low effort were 0.81 and 0.92, respectively. Bench experiments showed a low mean bias for P0.1vent compared with P0.1ref for most ventilators but precision varied; in patients, precision was lower. Ventilators estimating P0.1vent without occlusions could underestimate P0.1ref.Conclusions: P0.1 is a reliable bedside tool to assess respiratory drive and detect potentially injurious inspiratory effort.

Effectiveness of a chest physiotherapy care map in hospitalized patients

BACKGROUND

Conventional chest physiotherapy (chest PT) has been widely used to facilitate airway clearance. However, conventional chest PT is time consuming, unnecessary prescriptions result in heavier workloads for therapists. Therefore, judicious prescription of chest PT is important.

PURPOSE

To develop a chest physiotherapy care-map and evaluate its efficacy.

METHOD

Seventy-eight hospitalized patients who were consulted for chest PT were enrolled and consecutively allocated into two groups of 39 patients. Group I and II was enrolled before and after the implementation of the chest PT map, respectively.

RESULT

After the care-map was implemented, the chest PT prescription rate decreased from 56.4% to 33.3%, (p = 0.040). The duration of conventional chest PT trended to lower but not reaching significance from 4.5 (1-28) to 4 (2-9) days, (p = 0.582). The mean cost of chest PT was reduced by 38.2% (p = 0.019).

CONCLUSION

Chest PT care-map is an effective tool to reduce unnecessary chest PT prescriptions, lower costs, and more effectively allocate therapist time.

Association of Low Baseline Diaphragm Muscle Mass With Prolonged Mechanical Ventilation and Mortality Among Critically Ill Adults

IMPORTANCE

Low diaphragm muscle mass at the outset of mechanical ventilation may predispose critically ill patients to poor clinical outcomes.

OBJECTIVE

To determine whether lower baseline diaphragm thickness (Tdi) is associated with delayed liberation from mechanical ventilation and complications of acute respiratory failure (reintubation, tracheostomy, prolonged ventilation >14 days, or death in the hospital).

DESIGN, SETTING, AND PARTICIPANTS

Secondary analysis (July 2018 to June 2019) of a prospective cohort study (data collected May 2013 to January 2016). Participants were 193 critically ill adult patients receiving invasive mechanical ventilation at 3 intensive care units in Toronto, Ontario, Canada.

EXPOSURES

Diaphragm thickness was measured by ultrasonography within 36 hours of intubation and then daily. Patients were classified as having low or high diaphragm muscle mass according to the median baseline Tdi.

MAIN OUTCOMES AND MEASURES

The primary outcome was time to liberation from ventilation accounting for the competing risk of death and adjusting for age, body mass index, severity of illness, sepsis, change in Tdi during ventilation, baseline comorbidity, and study center. Secondary outcomes included in-hospital death and complications of acute respiratory failure.

RESULTS

A total of 193 patients were available for analysis; the mean (SD) age was 60 (15) years, 73 (38%) were female, and the median (interquartile range) Sequential Organ Failure Assessment score was 10 (8-13). Median (interquartile range) baseline Tdi was 2.3 (2.0-2.7) mm. In the primary prespecified analysis, baseline Tdi of 2.3 mm or less was associated with delayed liberation from mechanical ventilation (adjusted hazard ratio for liberation, 0.51; 95% CI, 0.36-0.74). Lower baseline Tdi was associated a higher risk of complications of acute respiratory failure (adjusted odds ratio, 1.77; 95% CI, 1.20-2.61 per 0.5-mm decrement) and prolonged weaning (adjusted odds ratio, 2.30; 95% CI, 1.42-3.74). Lower baseline Tdi was also associated with a higher risk of in-hospital death (adjusted odds ratio, 1.47; 95% CI, 1.00-2.16 per 0.5-mm decrement), particularly after discharge from the intensive care unit (adjusted odds ratio, 2.68; 95% CI, 1.35-5.32 per 0.5-mm decrement).

CONCLUSIONS AND RELEVANCE

In this study, low baseline diaphragm muscle mass in critically ill patients was associated with prolonged mechanical ventilation, complications of acute respiratory failure, and an increased risk of death in the hospital.

Comparison of immunogenicity between intradermal and intramuscular injections of repeated annual identical influenza virus strains post-pandemic (2011-2012) in COPD patients

We compared the antibody responses and persistence of the reduced-dose, 9 µg hemagglutinin (HA)/strain intradermal (ID) injection via the Mantoux technique and the 15 μg HA/strain intramuscular (IM) injection of the repeated annual identical trivalent, inactivated, split-virion vaccine 2011-2012 in chronic obstructive pulmonary disease (COPD) patients. Eighty patients were randomized to ID (n = 41) and IM (n = 39) groups. Four weeks post-vaccination, the antibody responses of the two groups were similar; those for influenza A(H1N1)pdm09 and influenza A(H3N2)-but not influenza B-met the criteria of the Committee for Proprietary Medicinal Products (CPMP). The antibody responses for influenza A(H1N1)pdm09 rapidly declined in both groups, especially with the ID injection, whereas those for influenza A(H3N2) maintained above the CPMP criteria throughout 12 months post-vaccination. The geometric mean titres for influenza A(H1N1)pdm09 persisted above the protective threshold (≥ 40) until 6 months post-vaccination in both the ID and IM groups. The seroprotection rates of the ID and IM groups were above 60% until 3 months and 6 months post-vaccination, respectively. In conclusion, the 9 μg HA/strain ID injection of vaccine 2011-2012 elicited antibody responses similar to the standard dose of 15 μg of the HA/strain IM injection at 4 weeks post-vaccination. However, the antibody responses for influenza A(H1N1)pdm09 rapidly declined, especially in the case of the ID injection, whereas they were comparable for influenza A(H3N2). Additional strategies for increasing vaccine durability should be considered, especially for new pandemic strains affecting elderly COPD patients.

Effects of high-flow nasal cannula and non-invasive ventilation on inspiratory effort in hypercapnic patients with chronic obstructive pulmonary disease: a preliminary study

Background

Non-invasive ventilation (NIV) is preferred as the initial ventilatory support to treat acute hypercapnic respiratory failure in patients with chronic obstructive pulmonary disease (COPD). High-flow nasal cannula (HFNC) may be an alternative method; however, the effects of HFNC in hypercapnic COPD are not well known. This preliminary study aimed at assessing the physiologic effects of HFNC at different flow rates in hypercapnic COPD and to compare it with NIV.

Methods

A prospective physiologic study enrolled 12 hypercapnic COPD patients who had initially required NIV, and were ventilated with HFNC at flow rates increasing from 10 to 50 L/min for 15 min in each step. The primary outcome was the effort to breathe estimated by a simplified esophageal pressure–time product (sPTP_es). The other studied variables were respiratory rate, oxygen saturation (SpO₂), and transcutaneous CO₂ pressure (PtcCO₂).

Results

Before NIV initiation, the median [interquartile range] pH was 7.36 [7.28–7.37] with a PaCO₂ of 51 [42–60] mmHg. sPTP_es per minute was significantly lower with HFNC at 30 L/min than 10 and 20 L/min (p < 0.001), and did not significantly differ with NIV (median inspiratory/expiratory positive airway pressure of 11 [10–12] and [5–5] cmH₂O, respectively). At 50 L/min, sPTPes per minute increased compared to 30 L/min half of the patients. Respiratory rate was lower (p = 0.003) and SpO₂ was higher (p = 0.028) with higher flows (30–50 L/min) compared to flow rate of 10 L/min and not different than with NIV. No significant differences in PtcCO₂ between NIV and HFNC at different flow rates were observed (p = 0.335).

Conclusions

Applying HFNC at 30 L/min for a short duration reduces inspiratory effort in comparison to 10 and 20 L/min, and resulted in similar effect than NIV delivered at modest levels of pressure support in hypercapnic COPD with mild to moderate exacerbation. Higher flow rates reduce respiratory rate but sometimes increase the effort to breathe. Using HFNC at 30 L/min in hypercapnic COPD patients should be further evaluated. Trial registration Thai Clinical Trials Registry, TCTR20160902001. Registered 31 August 2016, http://www.clinicaltrials.in.th/index.php?tp=regtrials&menu=trialsearch&smenu=fulltext&task=search&task2=view1&id=2008.

High-flow nasal oxygen versus noninvasive ventilation in adult patients with cystic fibrosis: a randomized crossover physiological study

Background

Noninvasive ventilation (NIV) is the first-line treatment of adult patients with exacerbations of cystic fibrosis (CF). High-flow nasal oxygen therapy (HFNT) might benefit patients with hypoxemia and can reduce physiological dead space. We hypothesized that HFNT and NIV would similarly reduce work of breathing and improving breathing pattern in CF patients. Our objective was to compare the effects of HFNT versus NIV in terms of work of breathing, assessed noninvasively by the thickening fraction of the diaphragm (TFdi, measured with ultrasound), breathing pattern, transcutaneous CO₂ (PtcCO₂), hemodynamics, dyspnea and comfort.

Methods

Adult CF patients who had been stabilized after requiring ventilatory support for a few days were enrolled and ventilated with HFNT and NIV for 30 min in crossover random order.

Results

Fifteen patients were enrolled. Compared to baseline, HFNT, but not NIV, reduced respiratory rate (by 3 breaths/min, p = 0.01) and minute ventilation (by 2 L/min, p = 0.01). Patients also took slightly larger tidal volumes with HFNT compared to NIV (p = 0.02). TFdi per breath was similar under the two techniques and did not change from baseline. MAP increased from baseline with NIV and compared to HFNT (p ≤ 0.01). Comfort was poorer with the application of both HFNT and NIV than baseline. No differences were found for heart rate, SpO₂, PtcCO₂ or dyspnea.

Conclusions

In adult CF patients stabilized after indication for ventilatory support, HFNT and NIV have similar effects on diaphragmatic work per breath, but high-flow therapy confers additional physiological benefits by decreasing respiratory rate and minute ventilation.

Clinical trial registration

Ethics Committee of St. Michael’s Hospital (REB #14-338) and clinicaltrial.gov (NCT02262871).

Electronic supplementary material

The online version of this article (10.1186/s13613-018-0432-4) contains supplementary material, which is available to authorized users.

Effort to Breathe with Various Spontaneous Breathing Trial Techniques. A Physiologic Meta-analysis

RATIONALE

Spontaneous breathing trials (SBTs) are designed to simulate conditions after extubation, and it is essential to understand the physiologic impact of different methods.

OBJECTIVES

We conducted a systematic review and pooled measures reflecting patient respiratory effort among studies comparing SBT methods in a meta-analysis.

METHODS

We searched Medline, Excerpta Medica Database, and Web of Science from inception to January 2016 to identify randomized and nonrandomized clinical trials reporting physiologic measurements of respiratory effort (pressure-time product) or work of breathing during at least two SBT techniques. Secondary outcomes included the rapid shallow breathing index (RSBI), and effort measured before and after extubation. The quality of physiologic measurement and research design was appraised for each study. Outcomes were analyzed using ratio of means.

MEASUREMENTS AND MAIN RESULTS

Among 4,138 citations, 16 studies (n = 239) were included. Compared with T-piece, pressure support ventilation significantly reduced work by 30% (ratio of means [RoM], 0.70; 95% confidence interval [CI], 0.57-0.86), effort by 30% (RoM, 0.70; 95% CI, 0.60-0.82), and RSBI by 20% (RoM, 0.80; 95% CI, 0.75-0.86). Continuous positive airway pressure had significantly lower pressure-time product by 18% (RoM, 0.82; 95% CI, 0.68-0.999) compared with T-piece, and reduced RSBI by 16% (RoM, 0.84; 95% CI, 0.74-0.95). Studies comparing SBTs with the postextubation period demonstrated that pressure support induced significantly lower effort and RSBI; T-piece reduced effort, but not the work, compared with postextubation. Work, effort, and RSBI measured while intubated on the ventilator with continuous positive airway pressure of 0 cm H₂O were no different than extubation.

CONCLUSIONS

Pressure support reduces respiratory effort compared with T-piece. Continuous positive airway pressure of 0 cm H₂O and T-piece more accurately reflect the physiologic conditions after extubation.

Trials directly comparing alternative spontaneous breathing trial techniques: a systematic review and meta-analysis

BACKGROUND

The effect of alternative spontaneous breathing trial (SBT) techniques on extubation success and other clinically important outcomes is uncertain.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, CINAHL, Evidence-Based Medicine Reviews, Ovid Health Star, proceedings of five conferences (1990-2016), and reference lists for randomized trials comparing SBT techniques in intubated adults or children. Primary outcomes were initial SBT success, extubation success, or reintubation. Two reviewers independently screened citations, assessed trial quality, and abstracted data.

RESULTS

We identified 31 trials (n = 3541 patients). Moderate-quality evidence showed that patients undergoing pressure support (PS) compared with T-piece SBTs (nine trials, n = 1901) were as likely to pass an initial SBT (risk ratio (RR) 1.00, 95% confidence interval (CI) 0.89-1.11; I 2 = 77%) but more likely to be ultimately extubated successfully (RR 1.06, 95% CI 1.02-1.10; 11 trials, n = 1904; I 2 = 0%). Exclusion of one trial with inconsistent results for SBT and extubation outcomes suggested that PS (vs T-piece) SBTs also improved initial SBT success (RR 1.06, 95% CI 1.01-1.12; I 2 = 0%). Limited data suggest that automatic tube compensation plus continuous positive airway pressure (CPAP) vs CPAP alone or PS increase SBT but not extubation success.

CONCLUSIONS

Patients undergoing PS (vs T-piece) SBTs appear to be 6% (95% CI 2-10%) more likely to be extubated successfully and, if the results of an outlier trial are excluded, 6% (95% CI 1-12%) more likely to pass an SBT. Future trials should investigate patients for whom SBT and extubation outcomes are uncertain and compare techniques that maximize differences in support.

A diaphragmatic electrical activity-based optimization strategy during pressure support ventilation improves synchronization but does not impact work of breathing

Background

Poor patient-ventilator synchronization is often observed during pressure support ventilation (PSV) and has been associated with prolonged duration of mechanical ventilation and poor outcome. Diaphragmatic electrical activity (Eadi) recorded using specialized nasogastric tubes is a surrogate of respiratory brain stem output. This study aimed at testing whether adapting ventilator settings during PSV using a protocolized Eadi-based optimization strategy, or Eadi-triggered and -cycled assisted pressure ventilation (or PSV_N) could (1) improve patient-ventilator interaction and (2) reduce or normalize patient respiratory effort as estimated by the work of breathing (WOB) and the pressure time product (PTP).

Methods

This was a prospective cross-over study. Patients with a known chronic pulmonary obstructive or restrictive disease, asynchronies or suspected intrinsic positive end-expiratory pressure (PEEP) who were ventilated using PSV were enrolled in the study. Four different ventilator settings were sequentially applied for 15 minutes (step 1: baseline PSV as set by the clinician, step 2: Eadi-optimized PSV to adjust PS level, inspiratory trigger, and cycling settings, step 3: step 2 + PEEP adjustment, step 4: PSV_N). The same settings as step 3 were applied again after step 4 to rule out a potential effect of time. Breathing pattern, trigger delay (T_d), inspiratory time in excess (T_iex), pressure-time product (PTP), and work of breathing (WOB) were measured at the end of each step.

Results

Eleven patients were enrolled in the study. Eadi-optimized PSV reduced T_d without altering T_iex in comparison with baseline PSV. PSV_N reduced T_d and T_iex in comparison with baseline and Eadi-optimized PSV. Respiratory pattern did not change during the four steps. The improvement in patient-ventilator interaction did not lead to changes in WOB or PTP.

Conclusions

Eadi-optimized PSV allows improving patient ventilator interaction but does not alter patient effort in patients with mild asynchrony.

Trial registration

Clinicaltrials.gov identifier: NCT 02067403. Registered 7 February 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1599-z) contains supplementary material, which is available to authorized users.

The immunogenicity of the intradermal injection of seasonal trivalent influenza vaccine containing influenza A(H1N1)pdm09 in COPD patients soon after a pandemic

The antibody responses of a reduced-dose intradermal seasonal influenza vaccination have never been studied in COPD patients soon after a pandemic. A total of 149 COPD patients (60 y of age or older) were randomized to receive trivalent influenza vaccine (Sanofi-Pasteur, France) either 9 µg of hemagglutinin (HA) per strain split into 2-site intradermal (ID) injections via the Mantoux technique or one intramuscular (IM) injection of 15 µg of HA per strain. The geometric mean titers, seroconversion factors, seroconversion rates and seroprotection rates for influenza A(H3N2) and B administered through the ID injection (n = 75) were similar to those obtained with the IM injection (n = 74) 4 weeks post-vaccination. The antibody responses for influenza A(H1N1)pdm09 administered through the ID injection were lower than those obtained with the IM injection, but all of these responses met the 3 criteria proposed by the Committee for Proprietary Medicinal Products (CPMP) for annual re-licensure. The seroprotection rates 4 weeks post-vaccination for influenza A(H1N1)pdm09 were 64.0% (95%CI 52.7-74.0%) in the ID group vs. 78.4% (95% CI 67.6-86.3%) in the IM group (p = 0.053). Influenza-related acute respiratory illness (ARI), diagnosed as a 4-fold rise in HI titers with a convalescent titer > 1:40, and/or the RT-PCR between the ID group (5.3%) and the IM group (8.1%) were not significantly different. The reduced-dose intradermal influenza vaccine may expand vaccine coverage in cases of vaccine shortage.

Accuracy of delivered airway pressure and work of breathing estimation during proportional assist ventilation: a bench study

Background

Proportional assist ventilation+ (PAV+) delivers airway pressure (P_aw) in proportion to patient effort (P_mus) by using the equation of motion of the respiratory system. PAV+ calculates automatically respiratory mechanics (elastance and resistance); the work of breathing (WOB) is estimated by the ventilator. The accuracy of P_mus estimation and hence accuracy of the delivered P_aw and WOB calculation have not been assessed. This study aimed at assessing the accuracy of delivered P_aw and calculated WOB by PAV+ and examining the factors influencing this accuracy.

Methods

Using an active lung model with different respiratory mechanics, we compared (1) the actual delivered P_aw by the ventilator to the theoretical P_aw as defined by the equation of motion and (2) the WOB value displayed by the ventilator to the WOB measured from a Campbell diagram.

Results

Irrespective of respiratory mechanics and gain, the ventilator provided a P_aw approximately 25 % lower than expected. This underassistance was greatest at the beginning of the inspiration. Intrinsic PEEP (PEEPi), associated with an increase in trigger delay, was a major factor affecting PAV+ accuracy. The absolute value of total WOB displayed by the ventilator was underestimated, but the changes in WOB were accurately detected by the ventilator.

Conclusion

The assistance provided by PAV+ well follows P_mus but with a constant underassistance. This is associated with an underestimation by the ventilator of the WOB. PEEPi can be a major factor contributing to PAV+ inaccuracy. Clinical recommendations should include using a high trigger sensitivity and a careful PEEP titration.

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-016-0131-y) contains supplementary material, which is available to authorized users.

Positive and negative effects of mechanical ventilation on sleep in the ICU: a review with clinical recommendations

PURPOSE

Sleep is an essential physiologic process that helps to restore normal body homeostasis. Sleep disturbances have been shown to be associated with poor clinical outcomes, such as a greater risk of cardiovascular disease and increasing mortality. Critically ill patients, particularly those receiving mechanical ventilation, may be more susceptible to sleep disruption.

METHODS AND RESULTS

Mechanical ventilation is an important factor influencing sleep in critically ill patients as it may have positive or negative effects, depending on patient population, mode, and specific settings. Other causes of sleep disruption include the acute illness itself, the daily routine care, and the effects of medications. Improving sleep in patients admitted to an intensive care unit has the potential to improve both short- and long-term clinical outcomes. In this article we review the specific aspects of sleep in critically ill mechanically ventilated patients, including abnormal sleep patterns and loss of circadian rhythm, as well as the effects of mechanical ventilation and intravenous sedatives on sleep quality and quantity.

CONCLUSIONS

We provide recommendations for clinicians regarding optimal ventilatory settings and discuss fields for future research.

Pressure-Controlled vs Volume-Controlled Ventilation in Acute Respiratory Failure: A Physiology-Based Narrative and Systematic Review

BACKGROUND

Mechanical ventilation is a cornerstone in the management of acute respiratory failure. Both volume-targeted and pressure-targeted ventilations are used, the latter modes being increasingly used. We provide a narrative review of the physiologic principles of these two types of breath delivery, performed a literature search, and analyzed published comparisons between modes.

METHODS

We performed a systematic review and meta-analysis to determine whether pressure control-continuous mandatory ventilation (PC-CMV) or pressure control-inverse ratio ventilation (PC-IRV) has demonstrated advantages over volume control-continuous mandatory ventilation (VC-CMV). The Cochrane tool for risk of bias was used for methodologic quality. We also introduced physiologic criteria as quality indicators for selecting the studies. Outcomes included compliance, gas exchange, hemodynamics, work of breathing, and clinical outcomes. Analyses were completed with RevMan5 using random effects models.

RESULTS

Thirty-four studies met inclusion criteria, many being at high risk of bias. Comparisons of PC-CMV/PC-IRV and VC-CMV did not show any difference for compliance or gas exchange, even when looking at PC-IRV. Calculating the oxygenation index suggested a poorer effect for PC-IRV. There was no difference between modes in terms of hemodynamics, work of breathing, or clinical outcomes.

CONCLUSIONS

The two modes have different working principles but clinical available data do not suggest any difference in the outcomes. We included all identified trials, enhancing generalizability, and attempted to include only sufficient quality physiologic studies. However, included trials were small and varied considerably in quality. These data should help to open the choice of ventilation of patients with acute respiratory failure.

Use of High-Flow Nasal Cannula for Acute Dyspnea and Hypoxemia in the Emergency Department

BACKGROUND

Acute dyspnea and hypoxemia are 2 of the most common problems in the emergency room. Oxygen therapy is an essential supportive treatment to correct these issues. In this study, we investigated the physiologic effects of high-flow nasal oxygen cannula (HFNC) compared with conventional oxygen therapy (COT) in subjects with acute dyspnea and hypoxemia in the emergency room.

METHODS

A prospective randomized comparative study was conducted in the emergency department of a university hospital. Forty subjects were randomized to receive HFNC or COT for 1 h. The primary outcome was level of dyspnea, and secondary outcomes included change in breathing frequency, subject comfort, adverse events, and rate of hospitalization.

RESULTS

Common causes of acute dyspnea and hypoxemia were congestive heart failure, asthma exacerbation, COPD exacerbation, and pneumonia. HFNC significantly improved dyspnea (2.0 ± 1.8 vs 3.8 ± 2.3, P = .01) and subject comfort (1.6 ± 1.7 vs 3.7 ± 2.4, P = .01) compared with COT. No statistically significant difference in breathing frequency was found between the 2 groups at the end of the study. HFNC was well tolerated, and no serious adverse events were found. The rate of hospitalization in the HFNC group was lower than in the COT group, but there was no statistically significant difference (50% vs 65%, P = .34).

CONCLUSIONS

HFNC improved dyspnea and comfort in subjects presenting with acute dyspnea and hypoxemia in the emergency department. HFNC may benefit patients requiring oxygen therapy in the emergency room.

Recent advances in mechanical ventilation in patients with acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is characterised by different degrees of severity and different stages. Understanding these differences can help to better adapt the ventilatory settings to protect the lung from ventilator-induced lung injury by reducing hyperinflation or keeping the lung open when it is possible. The same therapies may be useful and beneficial in certain forms of ARDS, and risky or harmful at other stages: this includes high positive end-expiratory pressure, allowance of spontaneous breathing activity or use of noninvasive ventilation. The severity of the disease is the primary indicator to individualise treatment. Monitoring tools such as oesophageal pressure or lung volume measurements may also help to set the ventilator. At an earlier stage, an adequate lung protective strategy may also help to prevent the development of ARDS.

Extensive pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis is a rare pulmonary disorder that is caused by abnormal sodium-dependent phosphate co-transporter from the mutation of SLC34A2 gene, leading to accumulation of microliths in the alveoli. We report the extensive pulmonary alveolar microlithiasis in an elderly woman who presented with progressive dyspnea for 2 months. Chest radiograph revealed diffuse pulmonary calcification. Tissue histopathology from open lung biopsy demonstrated widespread intra-alveolar laminated calcium deposits compatible with pulmonary alveolar microlithiasis.

High-flow nasal cannula versus conventional oxygen therapy after endotracheal extubation: a randomized crossover physiologic study

OBJECTIVE

Compare the short-term benefit of high-flow nasal cannula (HFNC) with non-rebreathing mask in terms of change in dyspnea, physiologic variables, and patient comfort in subjects after endotracheal extubation.

METHODS

A randomized crossover study was conducted in a 10-bed respiratory care unit in a university hospital. Seventeen mechanically ventilated subjects were randomized after extubation to either Protocol A (applied HFNC for 30 min, followed by non-rebreathing mask for another 30 min) or Protocol B (applied non-rebreathing mask for 30 min, followed by HFNC for another 30 min). The level of dyspnea, breathing frequency, heart rate, blood pressure, oxygen saturation, and patient comfort were recorded. The results were expressed as mean ± SD, frequency, or percentage. Categorical variables were compared by chi-square test or Fisher exact test, and continuous variables were compared by dependent or paired t test. Statistical significance was defined as P < .05.

RESULTS

Seventeen subjects were divided into 2 groups: 9 subjects in Protocol A and 8 subjects in Protocol B. The baseline characteristics and physiologic parameters before extubation were not significantly different in each protocol. At the end of study, HFNC indicated less dyspnea (P = .04) and lower breathing frequency (P = .009) and heart rate (P = .006) compared with non-rebreathing mask. Most of the subjects (88.2%) preferred HFNC to non-rebreathing mask.

CONCLUSIONS

HFNC can improve dyspnea and physiologic parameters, including breathing frequency and heart rate, in extubated subjects compared with conventional oxygen therapy. This device may have a potential role for use after endotracheal extubation.

Respiratory health effect of persons accidentally expose to high concentration of chlorine gas

OBJECTIVE

To evaluate the short term and long term respiratory health effects of subjects who accidentally exposed to high concentration of chlorine gas.

MATERIAL AND METHOD

There was an accidental leakage of sodium hypochlorite from an industrial factory in Rayong province in June 2010. Medical records of those who developed severe symptoms after exposed to high concentration of chlorine gas were reviewed. Prospective observational study was conducted after hospital discharge by interviewing with respiratory health questionnaires, physical examination, spirometry, methacholine challenge test, and home peak expiratory flow (PEF) monitoring at 2, 5 and 8 months after the event.

RESULTS

Among 1,434 persons exposed to chlorine gas, 92 developed severe symptoms required hospital admission and 21 participated in the follow-up study at 2 months there after. Respiratory symptoms were noted in 18 participants. Three most common symptoms were dyspnea (81%), chest tightness (71%), and cough (67%). Obstructive defect from spirometry was identified in 2 participants, one of which also had bronchial hyper responsiveness (BHR) compatible with reactive airway dysfunction syndrome (RADS). Seven participants had abnormal PEF variability. There were 10 and 5 participants left in the follow-up visit at 5 and 8 months respectively. Two participants had persistent obstructive defect with additional two subjects were noticed. Those who had BHR and abnormal PEF variability remained unchanged.

CONCLUSION

Acute exposure to high concentration of chlorine gas causes both significant short and long term respiratory health effects. Most of the patients although have gradual improvement of respiratory symptoms, but some symptoms remain persistent. Few patients have lung function impairment lasting for at least 8 months.

Prevalence of osteoporosis and osteopenia in Thai COPD patients

OBJECTIVE

To study the prevalence of osteoporosis and osteopenia in Thai COPD patients and the factors associated with osteoporosis.

MATERIAL AND METHOD

A cross sectional study was used to evaluate 102 male stable COPD patients. Bone mineral density at lumbar spine (L2-4) and femoral neck were measured by dual energy x-ray absorptiometer scan. Demographic data including age, body mass index (BMI), inhaled corticosteroids use, tobacco smoke, force expiratory volume at 1 second (FEV1), and high sensitivity C-reactive protein (hs-CRP) were analyzed.

RESULTS

The overall prevalence of osteoporosis and osteopenia according to the lowest T-score at either L2-4 or femoral neck were 31.4% and 32.4%, respectively. This prevalence of osteoporosis in COPD patients was higher than that in age-matched Thai males from historical data (31.4% vs. 12.6%, respectively). BMI and hs-CRP were significantly associated with osteoporosis. There was no association between osteoporosis and severity of COPD, age, smoking, and corticosteroid use. The predictive value of BMI < 20.5 kg/m2 and hs-CRP > 2.3 mg/L demonstrated risk of osteoporosis in COPD patients (adjusted Odds ratio 7.2 and 4.1, respectively).

CONCLUSION

The prevalence of osteoporosis and osteopenia in Thai COPD patients was higher than that in normal age-matched Thai males. Osteoporosis was associated with low BMl and high level of hs-CRP when compared to COPD patients with normal bone mineral density.

Amyloidosis and respiratory tract involvement: report of two cases

Amyloidosis is a group of diseases in which amyloid deposit in the extracellular space in an abnormal insoluble fibrillar form. The most important amyloid precursors are immunoglobulin light chain (AL) and serum amyloid-associated protein (AA). Amyloidosis can manifest as localized or systemic disease and respiratory system is one of the target organs that can be involved by amyloid. The authors report two cases of pulmonary amyloidosis presented with diffuse interstitial pulmonary amyloidosis and tracheobronchial involvement.