Table 3. Comparison of fatigue at end of “first vs last shift” in block of day and night shifts (3–4 shifts).

End of shift PVT measurements†	First shift	Last shift	p-value*
	Mean (95% CI)	Mean (95% CI)
Day shift (n = 16)
RTM (ms)	298.1 (291.8–304.5)	297.7 (278.9–317.8)	0.966
RTCV (ms)	25.0 (18.1–34.4)	27.1 (22.3–32.9)	0.368
Lapses (number of)	1.6 (0.8–2.4)	2.8 (1.7–3.9)	0.013
Night shift (n = 22)
RTM (ms)	320.4 (283.3–362.4)	335.1 (301.3–372.6)	0.301
RTCV (ms)	27.5 (20.0–37.8)	36.2 (28.8–45.6)	0.062
Lapses (number of)	3.6 (2.0–5.3)	7.3 (4.0–10.6)	0.009

RTM, mean reaction time; RTCV, relative coefficient of variation; ms, milliseconds; PVT, psychomotor vigilance task; CI, confidence interval.

*p-values were derived using regression analysis for timing of shift effects using the F distribution.

†All end of shift PVT measurements are adjusted for response at the start of shift.