A prolonged ICU stay after interhospital transport?

[1-3]. Barratt and colleagues studied patients transferred for nonclinical reasons to evaluate the consequences of transportation [4]. Th ere was no diff erence in mortality but the ICU length of stay (LOS) increased by 3 days, which was explained as a negative impact of the transport on patient physiology. We disagree with this conclusion. First, by including only transports to level 3 ICUs the received level of care for transported patients will increase, introducing a bias. Second, the increase in LOS can be interpreted as a result of selection bias, because patients with a short expected LOS would often not be considered eligible for transport. Also, since there was no increase in mortality, which would have been expected with an increased LOS, we might be looking at a mortality reduction as a result of the transfer to a higher-level ICU. Th ird, Barrett and colleagues suggest that deterioration of patient physiology during transport is probably respon sible for the increase in LOS. However, the reported Intensive Care National Audit and Research Centre scores before and after transport (although not validated for sequential patient assessments) do not support this assumption. Fourth, the method of transportation should have been included in this study. Specialised transport teams deliver patients with a better acute physiology compared with nonspecialised teams [2,5], making a need for regaining physiological stability unlikely. In conclusion, we congratulate Barratt and colleagues for their research. However, we think their conclusion is premature because multiple possible confounders were not taken into account.