[⇓][1] 

SERIES “ATS/ERS TASK FORCE: STANDARDISATION OF LUNG FUNCTION TESTING” 

Edited by V. Brusasco, R. Crapo and G. Viegi 

Number 2 in this Series

 [1]: #F13

/pdf/standardisation-of-spirometry-1dkqxgifvl.pdf

Standardisation of spirometry

Background Traditional approaches to mechanical ventilation use tidal volumes of 10 to 15 ml per kilogram of body weight and may cause stretch-induced lung injury in patients with acute lung injury and the acute respiratory distress syndrome. We therefore conducted a trial to determine whether ventilation with lower tidal volumes would improve the clinical outcomes in these patients. Methods Patients with acute lung injury and the acute respiratory distress syndrome were enrolled in a multicenter, randomized trial. The trial compared traditional ventilation treatment, which involved an initial tidal volume of 12 ml per kilogram of predicted body weight and an airway pressure measured after a 0.5-second pause at the end of inspiration (plateau pressure) of 50 cm of water or less, with ventilation with a lower tidal volume, which involved an initial tidal volume of 6 ml per kilogram of predicted body weight and a plateau pressure of 30 cm of water or less. The primary outcomes were death before a patient was discharged home and was breathing without assistance and the number of days without ventilator use from day 1 to day 28. Results The trial was stopped after the enrollment of 861 patients because mortality was lower in the group treated with lower tidal volumes than in the group treated with traditional tidal volumes (31.0 percent vs. 39.8 percent, P=0.007), and the number of days without ventilator use during the first 28 days after randomization was greater in this group (mean [+/-SD], 12+/-11 vs. 10+/-11; P=0.007). The mean tidal volumes on days 1 to 3 were 6.2+/-0.8 and 11.8+/-0.8 ml per kilogram of predicted body weight (P Conclusions In patients with acute lung injury and the acute respiratory distress syndrome, mechanical ventilation with a lower tidal volume than is traditionally used results in decreased mortality and increases the number of days without ventilator use.

Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome.

According to W. Edwards Deming, American companies require nothing less than a transformation of management style and of governmental relations with industry. In Out of the Crisis, originally published in 1982, Deming offers a theory of management based on his famous 14 Points for Management. Management's failure to plan for the future, he claims, brings about loss of market, which brings about loss of jobs. Management must be judged not only by the quarterly dividend, but by innovative plans to stay in business, protect investment, ensure future dividends, and provide more jobs through improved product and service. In simple, direct language, he explains the principles of management transformation and how to apply them.

Out of the Crisis

Objective:To provide an update to the “Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock,” last published in 2008.Design:A consensus committee of 68 international experts representing 30 international organizations was convened. Nominal groups were assembled at ke

Surviving sepsis campaign: international guidelines for management of severe sepsis and septic shock: 2012.

The acute respiratory distress syndrome (ARDS) was defined in 1994 by the American-European Consensus Conference (AECC); since then, issues regarding the reliability and validity of this definition have emerged. Using a consensus process, a panel of experts convened in 2011 (an initiative of the European Society of Intensive Care Medicine endorsed by the American Thoracic Society and the Society of Critical Care Medicine) developed the Berlin Definition, focusing on feasibility, reliability, validity, and objective evaluation of its performance. A draft definition proposed 3 mutually exclusive categories of ARDS based on degree of hypoxemia: mild (200 mm Hg < PaO2/FIO2 ≤ 300 mm Hg), moderate (100 mm Hg < PaO2/FIO2 ≤ 200 mm Hg), and severe (PaO2/FIO2 ≤ 100 mm Hg) and 4 ancillary variables for severe ARDS: radiographic severity, respiratory system compliance (≤40 mL/cm H2O), positive end-expiratory pressure (≥10 cm H2O), and corrected expired volume per minute (≥10 L/min). The draft Berlin Definition was empirically evaluated using patient-level meta-analysis of 4188 patients with ARDS from 4 multicenter clinical data sets and 269 patients with ARDS from 3 single-center data sets containing physiologic information. The 4 ancillary variables did not contribute to the predictive validity of severe ARDS for mortality and were removed from the definition. Using the Berlin Definition, stages of mild, moderate, and severe ARDS were associated with increased mortality (27%; 95% CI, 24%-30%; 32%; 95% CI, 29%-34%; and 45%; 95% CI, 42%-48%, respectively; P < .001) and increased median duration of mechanical ventilation in survivors (5 days; interquartile [IQR], 2-11; 7 days; IQR, 4-14; and 9 days; IQR, 5-17, respectively; P < .001). Compared with the AECC definition, the final Berlin Definition had better predictive validity for mortality, with an area under the receiver operating curve of 0.577 (95% CI, 0.561-0.593) vs 0.536 (95% CI, 0.520-0.553; P < .001). This updated and revised Berlin Definition for ARDS addresses a number of the limitations of the AECC definition. The approach of combining consensus discussions with empirical evaluation may serve as a model to create more accurate, evidence-based, critical illness syndrome definitions and to better inform clinical care, research, and health services planning.

Acute respiratory distress syndrome: the Berlin Definition.

Pulmonary tissue volume (Vti), carbon monoxide diffusing capacity, membrane diffusing capacity, pulmonary capillary blood flow and pulmonary capillary blood volume were measured in ninety (54 men and 36 women) healthy lifetime nonsmokers using an inert gas rebreathing technique. Prediction equations were generated using multiple linear regressions with height and age as the independent variables. Normalizing the data by dividing by functional residual capacity eliminated all sex differences. In contrast to the other variables, normalized pulmonary tissue volume did not correlate with any of the independent variables tested. Therefore, an average normalized Vti value can be recommended as a reference value

Reference values for pulmonary tissue volume, membrane diffusing capacity, and pulmonary capillary blood volume.

Implementation of a computerized patient advice system using the HELP clinical information system

It is not enough to merely manage medical information. It is difficult to justify the cost of hospital information systems (HIS) or intensive care unit (ICU) patient data management systems (PDMS) on this basis alone. The real benefit of an integrated HIS or PDMS is in decision support. Although there are a variety of HIS and ICU PDMS systems available there are few that provide ICU decision support. The HELP system at the LDS Hospital is an example of a HIS which provides decision support on many different levels. In the ICU there are decision support tools for antibiotic therapy, nutritional management, and management of mechanical ventilation. Computer protocols for the management of mechanical ventilation (respiratory evaluation, ventilation, oxygenation, weaning and extubation) in patients with adult respiratory distress syndrome ((ARDS) have already been developed and clinically validated at the LDS Hospital. These protocols utilize the bedside intensive care unit (ICU) computer terminal to prompt the clinical care team with therapeutic and diagnostic suggestions. The protocols (in paper flow diagram and computerized form) have been used for over 40,000 hours in more than 125 adult respiratory distress syndrome (ARDS) patients. The protocols controlled care for 94% of the time. The remainder of the time patient care was not protocol controlled was a result of the patient being in states not covered by current protocollogic (e.g. hemodynamic instability, or transport for X-Ray studies). 52 of these ARDS patients met extra corporal membrane oxygenation (ECMO) criteria. The survival of the ECMO criteria ARDS patients was 41%, four times that expected (9%) from historical data (p<0.0002). The success of these computer protocols and their acceptance by the clinical staff clearly establishes the feasibility of controlling the therapy of severely ill patients.

A Strategy for Development of Computerized Critical Care Decision Support Systems

Pulmonary function studies were performed on 13 survivors of adult respiratory distress syndrome (ARDS). Six of these 13 patients had a forced vital capacity (FVC) and total lung capacity (TLC) less than 80% of predicted within 2 months of the onset of ARDS. Seven patients followed 6 months or more showed no significant difference between measured and predicted FVC (p = 0.26) or TLC (p = 0.12). The diffusing capacity of carbon monoxide was significantly lower than predicted normal values (p < 0.001). Although the alveolar arterial oxygen tension gradient (ΔAapo2) was within the predicted normal range for 11 nonsmokers at rest, for 7 patients who exercised (1.0 < < 1.5 L/min), ΔAapo2 increased. The ratio of dead space to tidal volume decreased to less than 0.25 when exceeded 1.0 L/min. We concluded that lung mechanics return to predicted normal values within 4 to 6 months after ARDS, but abnormalities of pulmonary gas exchange persist. Pulmonary vascular obstruction does not appear to explain persistent ab...

Pulmonary function and exercise gas exchange in survivors of adult respiratory distress syndrome.

A total of 2711 pulmonary artery wedge pressure (WP) measurement attempts were made prospectively from WP recordings in 44 (30 men) critically ill patients, using 77 flow-directed catheters. Of these, 322 (12%) failed to yield a WP measurement, and 521 (18%) were associated with technical problems.

Alan H. Morris

Papers

Reference values for pulmonary tissue volume, membrane diffusing capacity, and pulmonary capillary blood volume.

Implementation of a computerized patient advice system using the HELP clinical information system

A Strategy for Development of Computerized Critical Care Decision Support Systems

Pulmonary function and exercise gas exchange in survivors of adult respiratory distress syndrome.

Frequency of technical problems encountered in the measurement of pulmonary artery wedge pressure.