Assessment of Pulse Oximeter Perfusion Index in Pediatric Caudal Block under Basal Ketamine Anesthesia
Table 3
Bedside indices for the onset of caudal block: numbers of patients meeting predefined “clinically obvious” targets indicative of onset of caudal block over time.
Pre-defined “clinically obvious” targets for positive test of onset of caudal block
Time after caudal injection (min)
Number (%) of patients reaching targets for positive test
Comparison with rPI for the same dose and time interval
rPI toe (100% change from time 0)
5
17/20 (85%)
—
10
19/20 (95%)
—
15
20/20 (100%)*
—
20
20/20 (100%)*
—
CR (absence %)
5
0/20 (0%)*
rPI > CR
0% for CR
10
2/20 (10%)
rPI > CR
15
9/20 (45%)
rPI > CR
100% for dPI*
20
20/20 (100%)
rPI = CR
100% for dPI, CR
rMAP (15% change from time 0)
5
0/20 (0%)*
rPI > rMAP
0% for rMAP
10
1/20 (5%)
rPI > rMAP
15
2/20 (10%)
rPI > rMAP
100% for dPI*
20
2/20 (10%)
rPI > rMAP
100% for dPI*
rHR (15% change from time 0)
5
0/20 (0%)*
rPI > rHR
0% for rHR
10
3/20 (15%)
rPI > rHR
15
4/20 (20%)
rPI > rHR
100% for dPI*
20
4/20 (20%)
rPI > rHR
100% for dPI*
PI: perfusion index; CR: cremasteric reflex; HR: heart rate; MAP: mean arterial pressure. Separate contingency tables were constructed to compare rPI with CR (absence %), rPI with rMAP, and rPI with rHR at each time point. Values are number (ratio). *Some contingency tables were so one-sided that they could not be assessed using McNemar’s test of symmetry, as there was either 100% positive data for rPI or 0% positive data for the comparison test. In these cases, the superiority of rPI was clearly self-evident.
