Force measurement
At baseline, the required force was applied in 9 (30%) and 8 (27%)
participants for “awake” and “anaesthetised” patients respectively.
Eight (27%) participants applied less than the force required to
prevent aspiration for “awake” patients and 18 (60%) applied less
than the required force for “anaesthetised” patients. Thirteen (43%)
participants applied forces greater than recommended for “awake”
patients and 4 (13%) participants applied greater than recommended
force for “anaesthetised” patients (Figure 5).
The LMM (random coefficient) had the best model fit as adjudged by the
information criteria for evaluating the difference in applied force
according to the 3 different teaching methods (Table 3). Baseline
cricoid pressure forces was a weak determinant of post-teaching cricoid
pressure forces (P= =0.053). LMM co-efficient and difference in
predicted force estimates for the biofeedback, nose and syringe methods
in “awake” and “anaesthetised” patients are shown in Tables 3 and 4.
Model estimates and marginal predictions of post-teaching forces between
the 3 teaching methods and in “awake” vs “anaesthetised” patients
yielded considerable differences in applied cricoid pressure.
Importantly, the biofeedback method led to predicted forces within the
recommended limit for both “awake” and “anaesthetised” patients.
Graphical representation of predicted force is displayed in Figure 6.