title: Flow rates through intravenous access devices: an in vitro study.
abstract: OBJECTIVE
  Fluid administration using intravenous (IV) access devices is required in many settings. There are a lack of quantitative data comparing traditional cannulas and modern access devices. We aimed to investigate flow rates through modern intravenous access devices using an in vitro system.
  
  
  METHODS
  This is an experimental study.
  Rates of flow of intravenous fluids (crystalloid and colloid) were measured through various access devices using a uroflowmeter. Standardized conditions and repeat measurements ensured validity. Fluid was administered with or without the addition of a pressure bag and needle-free valve.
  
  
  RESULTS
  Increasing the size of cannulas improved flow. Fourteen-gauge cannulas had significantly higher mean flow rates compared to 14G central venous lines in all conditions (136% higher with no pressure bag/valve; 95% CI, +130% to +152%; P < .001). Both the emergency infusion device and rapid infusion catheter produced significantly increased mean flows compared to a 14G cannula (12% higher for emergency infusion catheter; 95% CI, +7% to +15%; P = .008, and 15% higher for rapid infusion catheter; 95% CI, +12% to +21%; P = .004). The needle-free valve significantly impaired flow on 16G and wider IV access devices (36% lower with no pressure bag using 14G cannula; 95% CI, -29% to -46%; P = .003), but flow reductions in narrower IV access were insignificant. Pressure bags significantly improved flow in all devices, in all combinations.
  
  
  CONCLUSIONS
  Flow rates in IV devices can be maximized by pressure bag use and removal of needle-free valves. The rapid infusion catheter and emergency infusion catheter allow some increase in flow over a 14G cannula. Familiarity with varying flow rates across IV access devices could better inform clinical decisions.
authors.affiliation: National Women's Hospital, Auckland City Hospital, Auckland, New Zealand. Electronic address: khoyratty@gmail.com.
authors.forename: Saleem I
authors.initials: SI
authors.lastname: Khoyratty
authors.affiliation: Peterborough City Hospital, Peterborough, United Kingdom.
authors.forename: Pushpaj R
authors.initials: PR
authors.lastname: Gajendragadkar
authors.affiliation: National Women's Hospital, Auckland City Hospital, Auckland, New Zealand.
authors.forename: Kiran
authors.initials: K
authors.lastname: Polisetty
authors.affiliation: National Women's Hospital, Auckland City Hospital, Auckland, New Zealand.
authors.forename: Sue
authors.initials: S
authors.lastname: Ward
authors.affiliation: National Women's Hospital, Auckland City Hospital, Auckland, New Zealand.
authors.forename: Tim
authors.initials: T
authors.lastname: Skinner
authors.affiliation: Bedford Hospital NHS Trust, Bedford, United Kingdom.
authors.forename: Parag R
authors.initials: PR
authors.lastname: Gajendragadkar
mesh_terms: D000072601:Cannula; D000077324:Crystalloid Solutions; D004867:Equipment Design; D006801:Humans; D066298:In Vitro Techniques; D007262:Infusions, Intravenous / Q000295:instrumentation; D007552:Isotonic Solutions
chemical_list: D000077324:Crystalloid Solutions; D007552:Isotonic Solutions
keywords: Catheters; Drug administration routes; Drug therapy; Equipment and supplies; Therapeutics; Vascular access devices