A study in the Christmas issue published on bmj.com has said that the phrase "obs stable" in hospital notes is ambiguous and does not reliably indicate a patient's health status.
Dr Gregory Scott and colleagues argue that the phrase is potentially misleading and advise doctors to stop using it and write the observations in full.
The expression "obs stable" is written daily in hospital notes to indicate that there are no alarming problems with a patient's bedside nursing observations. Abnormalities in these observations act as an alarm for doctors when assessing patients.
But what does the term really mean?
To answer this question, Dr Scott and his team measured the range of observations which doctors recorded as "stable" to determine whether their use of the term is so liberal that it has become meaningless. They reviewed the case notes and nursing observations charts of 46 patients across three London teaching hospitals.
They found that at least one "stable" entry in the majority (78%) of notes reviewed. Observations in the 24 hours preceding an "obs stable" entry included at least one abnormality in almost three quarters (71%) of cases and at least one persistent abnormality in almost a fifth (19%) of cases.
The most common abnormalities were low blood pressure and rapid breathing. In some cases, they found that the range of observations over a 24-hour period that were designated as "stable" also exceeded normal values for diurnal variation.
The authors argue that the meaning of "obs stable" is ambiguous and does not reliably indicate normality. They say their findings should be considered preliminary, but they recommend that doctors should stop using the phrase altogether and write the observations in full, or qualify it by adding "for the last X hours."