When Time is of the Essence: Comparing Infusion Rates by Gravity, “Push-Pull” Technique and Pressure Bag Delivery

Authors

  • Fatimah Lateef Senior Consultant, Dept of Emergency Medicine, Singapore General Hospital, Core Faculty, Emergency Medicine Residency, Sing Health, Professor, Duke NUS Graduate Medical School, Yong Loo Lin School of Medicine, National University of Singapore and Lee Kong Chian Medical School, Nanyang Technological University, Director, SingHealth Duke NUS Institute of Medical Simulation (SIMS), Faculty, Duke NUS Global Health Institute, Singapore Author
  • Fatima Ezzahra Amasloukh1 17th Year Medical Student, Faculty of Medicine and Pharmacy of Casablanca, University Hassan II, Casablanca, Morocco Author
  • Goh Ying Hong 2Senior Executive, SingHealth Duke NUS Institute of Medical Simulation (SIMS), Singapore Author

DOI:

https://doi.org/10.47363/JCCEM/2025(4)183

Keywords:

Rapid Infusion, ‘Pressure Bag’ Infusion, Gravity Infusion, Simulation, Flow Rate, Viscosity, “Push-Pull” Technique

Abstract

Background: Rapid infusion is a fundamental component of resuscitation in trauma, conditions such as shock, perioperative bleeding and sepsis. The ability to deliver fluids and blood products swiftly and safely often determines the outcome of critical cases. Rapid fluid administration will help to restore volume, augment cardiac output and reverse shock. It represents one of the early interventions that can help reduce mortality and morbidity. In most emergency situations, peripheral intravenous (IV) access provides the fastest and most practical route for initial resuscitation when central access or automated rapid infusers are not yet available. However, infusion rate through a peripheral line is affected by multiple mechanical and physical factors, such as bag height, tubing length, cannula gauge, external pressure, and fluid viscosity.

Objective: To compare the flow rates via three peripheral infusion techniques gravity flow, pressure-bag assistance, and push–pull syringe method, using both normal saline and simulated blood at two pole heights (1.85 m and 1.50 m).

Methods: Thirty-six bench-simulation trials were conducted in a controlled laboratory using an 18-gauge cannula, standard transfusion tubing, and a
mannequin arm. Each combination of method, pole height, and fluid type was tested in triplicate (250 mL per run). Mean infusion times (seconds) and flow rates (mL/min) were recorded.

Results: Pressure-bag infusion produced the highest flow rate (118 ± 27 mL/min), significantly outperforming gravity (36 ± 7 mL/min) and push–pull syringe techniques (31 ± 2 mL/min) (p < 0.001). Raising the pole from 1.50 m to 1.85 m increased flow by 14–25%, depending on method. Saline infused faster than simulated blood (mean +23 mL/min, p < 0.05). The fastest combination was Pressure Bag + High Pole + Saline (139.7 mL/min), and the slowest was Gravity + Low Pole + Blood (26.7 mL/min).

Conclusion: External pressure and greater hydrostatic height substantially enhance infusion speed. Pressure-bag assistance offers a simple, effective solution when rapid infusion is required, particularly in emergency or low-resource settings.

Author Biographies

  • Fatimah Lateef, Senior Consultant, Dept of Emergency Medicine, Singapore General Hospital, Core Faculty, Emergency Medicine Residency, Sing Health, Professor, Duke NUS Graduate Medical School, Yong Loo Lin School of Medicine, National University of Singapore and Lee Kong Chian Medical School, Nanyang Technological University, Director, SingHealth Duke NUS Institute of Medical Simulation (SIMS), Faculty, Duke NUS Global Health Institute, Singapore

    Fatimah Lateef, Senior Consultant, Dept of Emergency Medicine, Singapore General Hospital, Core Faculty, Emergency Medicine Residency, Sing Health, Professor, Duke NUS Graduate Medical School, Yong Loo Lin School of Medicine, National University of Singapore and Lee Kong Chian Medical School, Nanyang Technological University, Director, SingHealth Duke NUS Institute of Medical Simulation (SIMS), Faculty, Duke NUS Global Health Institute, Singapore.

  • Fatima Ezzahra Amasloukh1, 17th Year Medical Student, Faculty of Medicine and Pharmacy of Casablanca, University Hassan II, Casablanca, Morocco

    17th Year Medical Student, Faculty of Medicine and Pharmacy of Casablanca, University Hassan II, Casablanca, Morocco.

  • Goh Ying Hong, 2Senior Executive, SingHealth Duke NUS Institute of Medical Simulation (SIMS), Singapore

    Senior Executive, SingHealth Duke NUS Institute of Medical Simulation (SIMS), Singapore.

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Published

2025-12-30

Issue

Vol. 4 No. 12 (2025): Volume 4 Issue 12

Section

Articles