Table 1
Demographic characteristics of study participants
|
Demographic variable |
Experienced (n = 8) mean ± SD |
Novice (n = 21) mean ± SD |
t-test comparisons |
Effect size | |||
|---|---|---|---|---|---|---|---|
|
t |
df |
p-value |
d |
95% CI | |||
|
Level of traininga |
2.75 ± 0.46 |
1.62 ± 0.87 |
−3.49 |
27 |
<0.01 |
1.45 |
0.55 to 2.35 |
|
Prior ultrasound trainingb |
2.25 ± 0.71 |
1.71 ± 0.64 |
−1.95 |
27 |
0.06 |
0.81 |
−0.03 to 1.65 |
|
Prior clinical point-of-care ultrasound procedures |
107 ± 94 |
12 ± 11 |
−2.83 |
7.07d |
0.03 |
0.99 |
0.13 to 1.84 |
|
Prior simulator exposurec |
0.75 ± 0.46 |
0.43 ± 0.51 |
−1.63 |
13.85d |
0.13 |
0.66 |
−0.18 to 1.49 |
SD standard deviation, df degrees of freedom, d effect size (Cohen’s d), CI confidence interval
a 0 medical student, 1 junior resident, 2 senior resident, 3 staff physician
b 0 none, 1 informal, 2 brief, 3 extensive
c 0 no, 1 yes
d df corrected to account for unequal variances
Fig. 1
Comparisons of experienced and novice performance in: a ultrasound image acquisition; b ultrasound image interpretation. Scenarios: 1 right kidney, 2 large pericardial effusion, 3 fluid in Morison’s pouch, 4 moderate pleural effusion. Notes: Scenarios are ordered here according to expected difficulty, but were completed in a different order by participants. The y‑axes depict the full range of possible performance scores
Fig. 2
Relationships between cognitive load rating (Paas scale) and image acquisition performance for: a Novice participants (n = 21); b Experienced participants (n = 8)
Table 2
Parameter estimates for marginal model with ultrasound image acquisition as the dependent variable and prior ultrasound training and cognitive load (Paas scale rating) as predictor variables
|
Fixed effect |
B (SE) |
df |
t-value |
p-value |
95% CI |
|---|---|---|---|---|---|
|
Intercept |
1.50 (0.27) |
113 |
5.64 |
<0.01 |
0.97 to 2.02 |
|
Prior ultrasound traininga |
0.22 (0.10) |
113 |
2.34 |
0.02 |
0.03 to 0.42 |
|
Cognitive loadb |
−0.14 (0.03) |
113 |
−4.05 |
<0.01 |
−0.21 to −0.07 |
|
Covariance parameter |
V (SE) |
Wald Z |
p-value | ||
|
Repeated measures |
0.48 (0.06) |
7.52 |
<0.01 | ||
B regression coefficient, SE standard error, df degrees of freedom, CI confidence interval, V covariance
a 0 none, 1 informal, 2 brief, 3 extensive
b range 1–9