Evaluation of a university hospital trauma team activation protocol

Table 2 Performance of the trauma team activation protocol during 2006-2007 at the University Hospital of North Norway Tromsø, evaluated with injury severity (ISS>15) and need for emergency procedure, n = 441

2 × 2 table for calculations on performance by injury severity				2 × 2 table for calculations on performance by need for emergency procedure
	ISS > 15	ISS ≤ 15	Sum		Procedure	No procedure	Sum
TTA	110 (a)	272 (b)	382	TTA	112 (a)	270 (b)	382
No TTA	51 (c)	unknown (d)	n/a	No TTA	30 (c)	unknown (d)	n/a
Sum	161	n/a	n/a	Sum	142	n/a	n/a
Performance by injury severity				Performance by need for emergency procedure
Sensitivity	PPV	Overtriage	Undertriage	Sensitivity	PPV	Over Triage	Undertriage
68%	29%	71%	32%	79%	29%	71%	21%

Sensitivity = a/(a + c), specificity = d/(b + d), Positive Predictive Value (PPV) = a/(a + b), Negative Predictive Value (NPV) = d/(c + d), Overtriage = 1 - PPV = b/(a + b), Undertriage = 1 - Sensitivity = c/(a + c). N/a = not applicable.
Specificity and NPV are not applicable to the dataset, as (d) is unknown because the total number of minor injuries can not be identified.

ISSN: 1757-7241