SARI For Tracheal Intubation

SARI For Tracheal Intubation 

The Simplified Airway Risk Index (SARI) is a multivariate model for airway assessment described by El-Ganzouri et al., enabling an estimation of the likelihood of a difficult direct laryngoscopy.

SARI studied under DIFFICAIR TRAIL in Denmark involving 28 Danish departments of anaesthesia and The Danish Anaesthesia Database (DAD) , a clinical database that contains selected quantifiable indicators, covering the anaesthetic process from the preoperative assessment through anaesthesia and surgery to the post-operative recovery period.

Seven parameters is used to calculate the SARI score: 

1. Mouth opening, 
2. Thyromental distance
3. Mallampati score
4. Movement of the neck
5. The ability to create an underbite
6. Body weight and 
7. Previously intubation history

Calculation :

1. Mouth opening: A mouth opening greater than 4 centimeters between the incisors results in 0 points whereas a distance below results in 1 point.
2. Thyromental distance:A thyromental distance greater than 6.5 centimeters results in 0 point whereas a distance between 6-6.5 centimeters is given 1 point and finally a distance below 6 centimeters is given 2 points.
3. Mallampati score: Class I and II of the modified mallampati scoring results in 0 points whereas a class III is given 1 point and a class IV 2 points.
4. Movement of the neck: The ability to move the neck more than 90 degrees results in 0 points whereas a movement range of 80-90 degrees results in 1 point and a movement range below 80 degrees results in 2 points.
5. Underbite: If the patient is able to protrude the jaw enough to create an underbite a score of 0 is given if not 1 point.
6. Body weight: A weight below 90 kilograms results in 0 points. A weight between 90 and 110 kilograms is given 1 point and a weight above 110 kilograms counts as 2 points.
7. Previous intubation history: If the patient has previously been intubated without any difficulties, a score of 0 points is given. If the patient has not previously been intubated, is unsure whether there where any difficulties or no records can be produced a score of 1 point is given. If there is a positive history of difficulties intubating 2 points is given.

Null hypothesis  

• There is no difference in the proportion of unanticipated difficult intubations when the preoperative airway assessment is based on the SARI score compared with a preoperative airway assessment based on the individual anaesthesiologist’s assessment.

• There is no difference in the proportion of unanticipated Difficult Mask Ventilation ( DMV  ) when the preoperative airway assessment includes systematic examination and registration of known predictors for DMV compared with an unstructured examination.

The trial is a cluster (cluster = department) and parallel group randomized trial stratified for the proportion of unanticipated difficult intubation. A total of 28 Danish departments of anaesthesia participate in the DIFFICAIR trial.

The departments were randomly assigned to one of two groups. In one group, anaesthesio-logists are trained in preoperative use of the SARI score (the SARI group) and in a control group the preoperative airway assessments of the anaesthesiologists are based solely on a clinical assessment (CA group).

Inclusion Criteria

Departments registering patients in the DAD with an expected minimum of 200 intubations annually are eligible for inclusion. Three populations of randomized patients are identified: 

1. Population 1: All patients primarily (attempted) intubated by direct laryngoscopy
2. Population 2: All patients primarily (attempted) intubated by direct laryngoscopy plus patients that are expected to be difficult to intubate by direct laryngoscopy and are therefore scheduled for intubation with an advanced method (e.g., video laryngoscopic or fibre-optic intubation)
3. Population 3: All patients undergoing mask ventilation

Exclusion Criteria

1. Children <15 years old
2. Patients who can not co-operate for the examination (unconscious, demented, severely traumatized, etc..)

Trial Period 

The trial period for 15 months which included 28 departments, randomized and stratified by a proportion of unanticipated difficult intubation less or greater than 2%. The departments are expected to have an average cluster size of approximately 2,500 patients, equalling allocation of approximately 35,000 patients for each trial group 9 total of 70,000 patients )

Statistical analysis 

The observed risk factors provide the basis for calculating the SARI score and for preoperative anticipation of a difficult intubation or not. Comparisons between the outcomes of the trial groups will be done on an individual level according to our sample size estimation. In the primary adjusted analysis, the number of patients having an unanticipated difficult (easy) intubation will be compared between the two trial groups with a logistic regression analysis adjusted for stratification variable of baseline proportions of unanticipated difficult (easy) intubation and clustering.

The accuracy of the SARI score will be compared with the accuracy of the clinical assessment in the Clinical Analysis  CA group on predicting difficult intubation. Additionally, the clinical assessment of the CA group will be compared with the clinical assessment of the SARI group based on the SARI score. That is, anticipations of intubation difficulties based on a clinical assessment only versus anticipations of intubation difficulties based on a clinical assessment while knowing the SARI score.

In all analyses, a P value less than 0.05 will be considered statistically significant

Conclusion 

However NO publications provided by Hillerod Hospital, Denmark as the final outcome of this trial. 

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We at TRAUMAGENCY found SARI as an intresting predictor for difficult intubation , despite no final outcome from the DIFFICAIR Trail team.

Source :  Trials Journal 

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