Page 85 - Ultrasonography in Prehospital and Emergency Medicine - Rein Ketelaars

Which ultrasound transducer type is best for diagnosing pneumothorax in pre-hospital care? 83
Time
The time the observers needed to reach a diagnosis is displayed in Table 3.3 and Figure 3.5.
After we fitted the linear mixed model, we found a significant difference between the time that elapsed until a final diagnosis was made. Whit the linear-array transducer the diagno- sis was made 0.51 seconds (p = .031) faster compared with the phased-array transducer. The curved-array transducer was 0.15 seconds (p = .049) faster than the phased-array transducer. We found no significant difference between the linear- and curved-array transducers. These comparisons between transducers are displayed in Table 3.4.
Table 3.3 Elapsed time until a diagnosis was made
Diagnosis
Linear-array transducer
Curved-array transducer
Phased-array transducer
All transducers combined
Normal ventilation Pneumothorax
All diagnoses(a)
2(1–5) 5(3–7) 4(2–6)
3(1–5.5) 5(3–7) 4(2–6)
3(2–5.5) 6(3.5–8.5) 4(2–7)
3(1–5)
5(3–7) 4(2–6.25)
a. This includes the ten clips without diagnosis.
The data are presented as median seconds (interquartile range).
Table 3.4
Linear-array Linear-array Curved-array
Difference in time elapsed until a diagnosis was made between transducer types
Compared transducers
Estimate [95% CI]
p value
vs Curved-array vs Phased-array vs Phased-array
–0.35 [–0.78, 0.07] .105 –0.51 [–0.97, –0.05] .031 –0.15 [–0.59, 0.28] .049
This table presents the differences in elapsed time until a diagnosis was made between a combination of two transducers, using a linear mixed model with a random intercept.
The differences are presented in seconds.
A negative value indicates that less time elapsed using the left of the two compared transducers.
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