Arterial waveform-analysis is of limited value in daily clinical practice in the intensive care unit.

Introduction: It is difficult to identify the patients who will respond to fluid therapy, but the arterial waveform-derived variables have reasonably predictive values for fluid responsiveness. However, the patient must fulfil a number of prerequisites for these variables to be valid. We assessed the proportion of intensive care unit (ICU) patients with shock who at the time of resuscitation fulfilled the prerequisites for using the arterial waveform-derived variables.

Methods: This was a prospective cohort study performed at six ICUs. The study included consecutive adult patients with shock (20 patients per ICU) who received fluid resuscitation on the first day of shock. The fulfilment or not of the prerequisites (sedation, sinus rhythm and controlled ventilation with tidal volumes > 7 ml/kg) was registered at the time of the first fluid resuscitation episode and at fluid resuscitation episodes during the following days.

Results: A total of 119 patients with a median age of 68 years (interquartile range: 56-76 years) were included. At the time of the first fluid resuscitation, 82% (95% confidence interval (CI): 74-87) of the patients had sinus rhythm, 77% (95% CI: 69-84) were sedated, 55% (95% CI: 46-65) were on controlled ventilation and 50% (95% CI: 39-61) received tidal volumes of more than 7 ml/kg. Only 23% (95% CI: 14-33) of the patients fulfilled all four prerequisites.

Conclusions: Less than a quarter of the ICU patients with shock fulfilled all the prerequisites for the use of arterial waveform-derived variables to predict fluid responsiveness. Thus, these variables may be of limited use during resuscitation in the ICU.