The grades of evidence (I-III) and levels of recommendations (I-III) are defined at the end of the "Major Recommendations" field.
Level I
There are insufficient data to support a Level I recommendation for this topic.
Level II
There are insufficient data to support a Level II recommendation for this topic.
Level III
Jugular venous saturation (<50%) or brain tissue oxygen tension (<15 mm Hg) are treatment thresholds.
Jugular venous saturation or brain tissue oxygen monitoring measures cerebral oxygenation.
Summary
Evidence supports a Level III recommendation for use of jugular venous saturation and brain tissue oxygen monitoring, in addition to standard intracranial pressure monitors, in the management of patients with severe traumatic brain injury (TBI). However, the accuracy of jugular venous saturation and brain tissue oxygen monitoring was not evaluated in this guideline. Current evidence suggests that episodes of desaturation (SjO2 <50–55%) are associated with worse outcomes, and high extraction (arterio-jugular difference of oxygen content [AJDO2]) are associated with good outcome. Low values of brain tissue oxygen tension (PbrO2) (<0–15 mm Hg) and the extent of their duration (greater than 30 min) are associated with high rates of mortality.
Though many technologies including cerebral microdialysis, thermal diffusion probes, transcranial Doppler, near-infrared spectroscopy, and others hold promise in advancing the care of severe TBI patients, there is currently insufficient evidence to determine whether the information they provide is useful for patient management or prognosis.
Definitions:
Grades of Evidence
Class I - Good quality randomized controlled trial (RCT)
Class II - Moderate quality RCT, good quality cohort, or good quality case-control
Class III - Poor quality RCT; moderate or poor quality cohort; moderate or poor case-control; or case series, databases, or registries
Levels of Recommendation
Levels of recommendation are Level I, II, and III, derived from Class I, II, and III evidence, respectively.
Level I - Recommendations are based on the strongest evidence for effectiveness, and represent principles of patient management that reflect a high degree of clinical certainty.
Level II - Recommendations reflect a moderate degree of clinical certainty.
Level III - Recommendations for which the degree of clinical certainty is not established.