Approach to Vascular Access

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🌱 來自: Huppert’s Notes

Approach to Vascular Access🚧 施工中

Approach to Vascular Access

TABLE 3.1 • Flow Relationship Defined by the Poiseuille Equation

•   Determinants of flow rate:

-   Catheter radius (larger radius → larger area → higher flows)

•   Small changes in radius have relatively large impacts on flow rates

•   Measured as French (Fr) vs. gauge

-   Two scales that reflect the diameter and therefore size of the lumen

•   Fr: Larger Fr catheters (i.e., higher number) have LARGER diameters

•   Gauge: Larger gauge catheters (i.e., higher numbers) have SMALLER diameters

-   Length of catheter (shorter catheter → higher flows)

-   Number of lumens (fewer lumens → higher flows)

-   Pressure difference (larger changes in pressure → higher flows rates)

•   Augment by using pressure bags, manually squeezing the bag, or increasing vertical distance between the fluid bag and the patient

-   Viscosity: More viscous products (i.e., blood) will flow more slowly

•   Venous site selection:

-   Internal jugular (most common)

•   Pros: High placement success rate, low risk of pneumothorax with ultrasound guidance

•   Cons: Possible higher rate of bloodstream infections compared to subclavian

-   Subclavian

•   Pros: Likely lowest rates of bloodstream infections of the three sites

•   Cons: Highest rate of pneumothorax, decreased placement success rate with less experienced providers

-   Femoral

•   Pros: High placement success rate, no pneumothorax risk. Often used in trauma or codes given site is away from intubation or CPR

•   Cons: Possible higher rate of bloodstream infections given location, limits patient mobility

•   Vascular access options for common patient scenarios:

-   Most patients in the ICU and medical wards:

•   Angiocath for peripheral venous access: Various sizes, including 14G, 16G, 18G, 20G, 22G

-   ICU patient with septic shock requiring vasopressors, multiple IV antibiotics, and other medications:

•   Triple-lumen central venous catheter: Contains three lumens which are 1 × 16G and 2 × 18G; catheter length from 15–30 cm selected based on patient size and insertion location

-   Gastrointestinal bleed requiring aggressive and rapid transfusion of multiple blood products:

•   MULTIPLE large-bore (often 16G or 18G) peripheral IVs

•   Alternative is an introducer or cordis, which are short catheters with large diameters, most commonly 8 Fr

-   Code blue → PEA arrest in a patient without IV access:

•   Intraosseous (IO) access into a long bone (often tibia) with a 15G tibial needle enabling rapid infusions; short-term use until other access can be obtained

-   Patient with endocarditis or osteomyelitis requiring long-term administration of antibiotics:

•   Peripherally inserted central catheter (PICC): Long catheters ranging from 30–60 cm in length; single-, double-, or triple-lumen options, with lumens being 4–5 Fr or 18G