The methods of arrangement of combined intravenous parallel infusions using anti-reflux valve (ARV), with and without anti-syphon valve (ASV) that could decrease occlusion alarm delay were investigated.

Occlusion challenge tests were mainly performed as bench experiments of four kinds of multiple parallel infusions (10 ml/h and 50 ml/h infusions), which were connected at the proximal or distal portion of ARV, with or without ASV. Alarm threshold was set to 1000 mmHg. Occlusion alarm delays and the compliances of the infusion systems were compared among groups.

Without ASV, compared to 10 ml/h infusion alone distal to anti-reflux valve, 50 ml/h infusion distal to anti-reflux valve reduced the mean alarm delay from 416 ± 7 s to 81 ± 3 s (P < 0.001). Compared to 50 ml/h infusion alone, combined 10 ml/h and 50 ml/h infusion distal to ARV prolonged the alarm delay from 81 ± 3 s to 133 ± 6 s (P < 0.001). However, combined infusions distal to ARV with ASV significantly reduced the alarm delay from 133 ± 6 s to 74 ± 5 s (P < 0.001), and also reduced the compliance of the infusion system from 2.31 ± 0.12 to 1.20 ± 0.08 µl/mmHg (P < 0.001).

The infusion setup of faster infusion rate, lower compliant system using ASV could effectively decrease occlusion alarm delay during multiple intravenous parallel infusions using ARV.