Anne Pohlman

Introduction: Pain assessment is associated with important outcomes in ICU patients but remains challenging, particularly in non-communicative patients. Use of a reliable tool is paramount to allow any implementation of sedation/analgesia protocols in a multidisciplinary team. This study compared psychometric properties (inter-rater agreement primarily; validity, responsiveness and feasibility secondarily) of three pain scales: Behavioural Pain Scale (BPS/BPS-NI, that is BPS for Non-Intubated patients), Critical Care Pain Observation Tool (CPOT) and Non-verbal Pain Scale (NVPS), the pain tool routinely used in this 16-bed medical ICU. Methods: Pain was assessed by at least one of four investigators and one of the 20 bedside nurses before, during and 10 minutes after routine care procedures in non-comatose patients (Richmond Agitation Sedation Scale ≥ -3) who were unable to self-report their pain intensity. The Confusion Assessment Method for the ICU was used to assess delirium. Non-parametric tests were used for statistical analysis. Quantitative data are presented as median (25^th to 75^th). Results: A total of 258 paired assessments of pain were performed in 30 patients (43% lightly sedated, 57% with delirium, 63% mechanically ventilated). All three scales demonstrated good psychometric properties. However, BPS and CPOT exhibited the best inter-rater reliability (weighted-κ 0.81 for BPS and CPOT) and the best internal consistency (Cronbach-α 0.80 for BPS, 0.81 for CPOT), which were higher than for NVPS (weighted-κ 0.71, P P <0.01). Responsiveness was significantly higher for BPS compared to CPOT and for CPOT compared to NVPS. For feasibility, BPS was rated as the easiest scale to remember but there was no significant difference in regards to users’ preference. Conclusions: BPS and CPOT demonstrate similar psychometric properties in non-communicative intubated and non-intubated ICU patients.

Introduction: Distinguishing pulmonary edema due to acute lung injury (ALI) or the acute respiratory distress syndrome (ARDS) from hydrostatic or cardiogenic edema is challenging in critically ill patients. B-type natriuretic peptide (BNP) can effectively identify congestive heart failure in the emergency room setting but, despite increasing use, its diagnostic utility has not been validated in the intensive care unit (ICU). Methods: We performed a prospective, blinded cohort study in the medical and surgical ICUs at the University of Chicago Hospitals. Patients were eligible if they were admitted to the ICU with respiratory distress, bilateral pulmonary edema and a central venous catheter suggesting either high-pressure (cardiogenic) or low-pressure (ALI/ARDS) pulmonary edema. BNP levels were measured within 48 hours of ICU admission and development of pulmonary edema and onward up to three consecutive days. All levels were drawn simultaneously with the measurement of right atrial or pulmonary artery wedge pressure. The etiology of pulmonary edema – cardiogenic or ALI/ARDS – was determined by three intensivists blinded to BNP levels. Results: We enrolled a total of 54 patients (33 with ALI/ARDS and 21 with cardiogenic edema). BNP levels were lower in patients with ALI/ARDS than in those with cardiogenic edema (496 ± 439 versus 747 ± 476 pg/ml, P = 0.05). At an accepted cutoff of 100 pg/ml, specificity for the diagnosis of ALI/ARDS was high (95.2%) but sensitivity was poor (27.3%). Cutoffs at higher BNP levels improved sensitivity at considerable cost to specificity. Invasive measures of filling pressures correlated poorly with initial BNP levels and subsequent day BNP values fluctuated unpredictably and without correlation with hemodynamic changes and net fluid balance. Conclusion: BNP levels drawn within 48 hours of admission to the ICU do not reliably distinguish ALI/ARDS from cardiogenic edema, do not correlate with invasive hemodynamic measurements, and do not track predictably with changes in volume status on consecutive daily measurements.