Abstract:
Background: Rapid crystalloid co-loading and prophylactic norepinephrine may share a peripheral intravenous catheter during cesarean delivery. We assessed whether infusion-system architecture alters fluid and drug delivery.
Methods: Six infusion-system configurations were tested in vitro. Norepinephrine 8 μg/mL was infused at 30 mL/h (4 μg/min) while 1000 mL saline was delivered from a pressure bag initially inflated to 300 mmHg. Outcomes were crystalloid volume delivered during the first 10 min, time within the norepinephrine target range of 3.5-4.5 μg/min, and the proportion of measurements outside ±12.5% of the configuration-specific median.
Results: Crystalloid volume at 10 min ranged from 596 ± 30 to 947 ± 30 mL between configurations (P < 0.001). Time within the norepinephrine target range ranged from 32.8 ± 6.1% to 71.4 ± 9.9% (P = 0.019), and instability ranged from 23.8 ± 6.2% to 54.6 ± 13.0% (P < 0.001). Among the configurations tested, those in which pressurized crystalloid entered downstream of the convergence of actively controlled drug infusions showed the most favorable balance between crystalloid delivery and norepinephrine stability.
Discussion: Infusion-system architecture influenced both rapid crystalloid delivery and distal norepinephrine stability. When pressurized crystalloid and actively controlled drugs share a peripheral intravenous catheter, a distal crystalloid entry may represent a favorable system architecture. Clinical relevance requires further evaluation.
Reference:Bonnet V, Décaudin B, Hureau M, Gonzalez Estevez M, Odou P, Lebuffe G, Genay S. Impact of the infusion line on co-loading and highly diluted norepinephrine administration through a single peripheral venous catheter: An in vitro simulation of the infusion protocol used during cesarean delivery under spinal anesthesia. Int J Obstet Anesth. 2026 Oct 1;68:105296. doi: 10.1016/j.ijoa.2026.105296. Epub ahead of print. PMID: 42887205.