Intensive care doctors' preferences for arterial oxygen tension levels in mechanically ventilated patients.

BACKGROUND: Oxygen is liberally administered in intensive care units (ICUs). Nevertheless, ICU doctors' preferences for supplementing oxygen are inadequately described. The aim was to identify ICU doctors' preferences for arterial oxygenation levels in mechanically ventilated adult ICU patients. METHODS: In April to August 2016, an online multiple-choice 17-part-questionnaire was distributed to 1080 ICU doctors in seven Northern European countries. Repeated reminder e-mails were sent. The study ended in October 2016. RESULTS: The response rate was 63%. When evaluating oxygenation 52% of respondents rated arterial oxygen tension (PaO2 ) the most important parameter; 24% a combination of PaO2 and arterial oxygen saturation (SaO2 ); and 23% preferred SaO2 . Increasing, decreasing or not changing a default fraction of inspired oxygen of 0.50 showed preferences for a PaO2 around 8 kPa in patients with chronic obstructive pulmonary disease, a PaO2 around 10 kPa in patients with healthy lungs, acute respiratory distress syndrome or sepsis, and a PaO2 around 12 kPa in patients with cardiac or cerebral ischaemia. Eighty per cent would accept a PaO2 of 8 kPa or lower and 77% would accept a PaO2 of 12 kPa or higher in a clinical trial of oxygenation targets. CONCLUSION: Intensive care unit doctors preferred PaO2 to SaO2 in monitoring oxygen treatment when peripheral oxygen saturation was not included in the question. The identification of PaO2 as the preferred target and the thorough clarification of preferences are important when ascertaining optimal oxygenation targets. In particular when designing future clinical trials of higher vs lower oxygenation targets in ICU patients.

Serum markers of collagen synthesis and degradation in acute respiratory failure patients.

BACKGROUND: Procollagen-derived propeptides reflect the rate of collagen synthesis and type I cross-linked collagen telopeptides (ICTP) collagen I degradation. We studied the collagen metabolism to find out if changes seen in acute respiratory distress syndrome patients are observed in patients with acute respiratory failure (ARF), and whether multiple organ dysfunction (MOD) has impact on it. METHODS: ARF patients with prolonged hospitalisation at least 21 days were included to the study. Blood samples for serum procollagen aminoterminal propeptide I (PINP) and III (PIIINP), and ICTP measurements were collected at study admission (day 0) and on days 2, 7, and 21. RESULTS: The study population comprised 68 patients. Forty-three patients (63%) developed MOD during the first week. PIIINP levels increased in all patients over time. The increase was slightly more pronounced in patients with MOD. During the first week, the synthesis of PIIINP increased more than PINP, and PINP degradation exceeded its production. By day 21, the balance of collagen metabolites returned to baseline. CONCLUSION: The collagen metabolism was altered in ARF patients. The first week was dominated by degradation of type I collagen and production of type III collagen, but by day 21, the collagen composition returned to more stable form.

Serum zinc in critically ill adult patients with acute respiratory failure.

BACKGROUND AND AIMS: Zinc deficiency leads to susceptibility to infections and may affect pulmonary epithelial cell integrity. Low zinc levels have also been associated with a degree of organ failure and decreased survival in critically ill children. Accordingly, the purpose of the study was to assess serum zinc in adult patients with acute respiratory failure, its association with ventilatory support time, intensive care unit (ICU) length of stay (LOS), organ dysfunction and 30-day mortality. METHODS: We included consecutive patients with acute respiratory failure during an eight-week prospective, observational multicentre study (the FINNALI-study). Acute respiratory failure was defined as a need for either non-invasive or invasive positive pressure ventilation for >6 h regardless of the underlying cause or risk factors. After informed consent, a sample for zinc measurement was drawn at 6 h after the start of treatment and analysed from 551 of these patients. RESULTS: Low serum zinc was frequent (95.8%) at the onset acute respiratory failure. The median interquartile range [IQR] was 4.7 [3.0-6.9] µmol/l. The median [IQR] serum zinc levels in non-infectious, sepsis and septic shock patients were 5.0 [3.1-7.1], 5.1 [3.5-7.3] and 3.8 [2.6-5.9] µmol/l, respectively, P<0.01. Baseline zinc levels were not associated with ventilatory support time (P=0.98) or ICU LOS (P=0.053). The area under curve in receiver operating characteristics analysis for serum zinc regarding 30-day mortality was 0.55 (95% CI 0.49-0.60). CONCLUSIONS: Serum zinc on initiation of ventilation had no predictive value for 30-day mortality, ventilatory support time or intensive care unit LOS.

N-terminal-pro-BNP in critically ill patients with acute respiratory failure: a prospective cohort study.

BACKGROUND: The aim of this study was to evaluate the prognostic value of plasma N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) in unselected critically ill patients with acute respiratory failure (ARF). METHODS: Prospective, observational cohort study in 25 intensive care units in Finland. This study included a total of 602 patients with laboratory samples from 958 consecutive patients with ARF treated either with invasive or with non-invasive ventilatory support (the FINNALI study). Plasma NT-pro-BNP samples were drawn after the onset of ventilatory support (day 0) and on the morning of the second day. RESULTS: The median [interquartile ranges (IQR)] NT-pro-BNP-values were significantly higher at baseline in 90-day non-survivors than the survivors, 4378 pg/ml (1400-13,943 pg/ml) vs. 1052 pg/ml (232-4076 pg/ml), respectively. The median (IQR) NT-pro-BNP values were significantly higher in patients with chronic cardiac disease or cardiac surgery than in non-cardiac patients, 1947 pg/ml (801-4687 pg/ml) vs. 417 pg/ml (153-1735 pg/ml), respectively, if renal function was normal. With deteriorating renal function, the NT-pro-BNP values showed a significant increase. The area under curve for baseline NT-pro-BNP predicting 90-day mortality was moderate: 0.718 (95% confidence interval 0.674-0.761). Baseline NT-pro-BNP over 1765 pg/ml was independently associated with 90-day mortality by logistic regression analysis (P<0.001). CONCLUSIONS: NT-pro-BNP on admission is commonly elevated and independently associated with 90-day mortality in critically ill ARF patients. However, the routine use of NT-pro-BNP for prognostic purpose does not seem to add value to clinical data in ARF patients.