Cannulas: Types, Sizes, Uses, and a Complete Buying Guide (2026)
A cannula is a thin, flexible medical tube inserted into the body to deliver fluids, medication, or oxygen, or to drain fluid out. The two most common types are the IV (intravenous) cannula, used to access a vein for fluids and medicines, and the nasal cannula, used to deliver supplemental oxygen. Cannulas come in different gauges (sizes), materials, and designs depending on the clinical purpose.
This guide covers everything a hospital, clinic, distributor, or home-care buyer needs to know about cannulas — what they are, the different types and sizes, how they're used, safety standards to look for, and how to source them reliably in bulk from OxyMed, a wholesale supplier and distributor of medical-grade cannulas.
What Is a Cannula?
A cannula is a small, hollow tube made of medical-grade plastic (PVC/PU) or stainless steel that clinicians insert into a vein, body cavity, or duct. The name comes from the Latin word for "little reed," which reflects its simple, tube-like shape.
Cannulas and catheters are often used interchangeably, though catheter usually refers specifically to devices used for bladder drainage, while "cannula" is the broader clinical term.
Common purposes of a cannula include:
- Delivering IV fluids, blood, or medication directly into a vein
- Drawing blood samples
- Supplying supplemental oxygen through the nose
- Draining fluid from a body cavity
- Assisting in surgical and cosmetic procedures (e.g., dermal filler placement, liposuction)
Types of Cannulas
1. IV (Intravenous) Cannulas
Also called peripheral IV catheters, these are inserted into a vein — typically in the arm or hand — to give fluids, medication, or blood. Subtypes include:
- Peripheral IV cannulas – the most common type, used for short-term access in hospitals, emergency rooms, and during surgery
- Central line cannulas – placed in larger, central veins for long-term treatment or when high-volume fluids are needed
- Winged (butterfly) cannulas – have plastic "wings" for easier handling and are often used for shorter infusions or in pediatric and geriatric patients
- Safety cannulas – include a mechanism that shields the needle after use to reduce the risk of needlestick injury to healthcare staff
2. Nasal Cannulas
A nasal cannula is a lightweight tube with two small prongs that rest inside the nostrils, connected to an oxygen source. It's used for patients who need low-to-moderate supplemental oxygen and is common in hospitals, ambulances, and home oxygen therapy.
- Standard nasal cannula – delivers up to 4–6 liters per minute (LPM) of oxygen
- High-flow nasal cannula (HFNC) – delivers higher, humidified oxygen flow for patients with more significant respiratory needs
3. Micro Cannulas (Aesthetic/Cosmetic Use)
Blunt-tipped micro cannulas are widely used in aesthetic medicine for dermal filler injections. Because the tip is blunt rather than sharp, they reduce the risk of puncturing blood vessels, which means less bruising and swelling compared to a needle.
4. Surgical Cannulas
Used in operating rooms for procedures such as laparoscopy, liposuction, and cardiac bypass surgery, where a cannula helps direct fluid, gas, or instruments into or out of the body.
Cannula Sizes and Gauge Guide
IV cannulas are sized by "gauge" — the smaller the gauge number, the larger the tube diameter. Each gauge is also color-coded for quick identification.
| Gauge | Color | Typical Flow Rate | Common Use |
|---|---|---|---|
| 14G | Orange | ~270 mL/min | Trauma, rapid blood transfusion |
| 16G | Grey | ~180 mL/min | Surgery, major fluid resuscitation |
| 18G | Green | ~90 mL/min | Blood transfusion, surgery |
| 20G | Pink | ~60 mL/min | General IV fluids and medication |
| 22G | Blue | ~35 mL/min | Standard adult and pediatric use |
| 24G | Yellow | ~20 mL/min | Pediatric, elderly, fragile veins |
| 26G | Purple | ~13 mL/min | Neonatal and very fine veins |
Flow rates are approximate and can vary by manufacturer and cannula design.
Cannula vs. Needle vs. Catheter: What's the Difference?
- Needle – a rigid, sharp instrument used to puncture skin, typically for a single injection or blood draw.
- Cannula – a flexible tube (often placed over or through a needle) that stays in the body for ongoing fluid or medication delivery, or that has a blunt tip for atraumatic insertion in aesthetic procedures.
- Catheter – functionally similar to a cannula, but the term is most often reserved for devices used to drain the bladder or access deeper structures.
In aesthetic medicine specifically, cannulas are increasingly preferred over needles because their blunt tip glides beneath the skin with a single entry point, reducing trauma, bruising, and the number of needle sticks required.
Sterility and Safety Standards to Look For
Because cannulas make direct contact with blood, tissue, or the airway, quality and sterility are non-negotiable. When sourcing cannulas — whether for a hospital, clinic, or distribution business — check for:
- ISO 13485 certification (quality management for medical devices)
- CE marking (compliance with EU medical device regulations) or local regulatory equivalents (e.g., CDSCO, FDA clearance)
- Single-use sterile packaging with clearly printed expiry dates and batch numbers
- Consistent gauge and material specifications across batches
- Documented flow-rate and durability testing
Buying from an unverified or uncertified source can introduce serious patient-safety and compliance risks, which is why hospitals and clinics increasingly work with established wholesale suppliers rather than one-off vendors.
How to Choose the Right Cannula Supplier
If you're procuring cannulas in bulk — for a hospital, pharmacy chain, aesthetic clinic network, or as a distributor — the supplier matters as much as the product. Look for:
- Certifications on file (ISO, CE, or country-specific approvals) that you can verify, not just claim.
- Range of gauges and types so you can order everything from IV to nasal to micro cannulas from one source.
- Batch consistency and traceability for regulatory and audit purposes.
- Realistic lead times and minimum order quantities (MOQs) that match your actual demand.
- Transparent pricing at wholesale volume, without hidden fees on reordering.
- Responsive support for reorders, damaged-stock claims, and documentation requests.
Why Healthcare Buyers Choose OxyMed
OxyMed is a wholesaler and supplier of medical-grade cannulas, working directly with hospitals, clinics, pharmacies, and distributors who need a dependable, compliant supply chain — not a one-time transaction.
What OxyMed focuses on for buyers:
- Full range of cannulas — IV/peripheral, safety, winged, nasal (standard and high-flow), and micro cannulas for aesthetic use — sourced to meet recognized sterility and quality standards.
- Consistent bulk supply so hospitals and distributors aren't left short during high-demand periods.
- Documentation support, including batch and certification paperwork, to help buyers meet their own compliance and audit requirements.
- Straightforward wholesale pricing designed for repeat, high-volume ordering rather than single retail purchases.
If your organization needs a steady, verifiable cannula supply chain, OxyMed's wholesale team can walk you through gauge options, order quantities, and documentation before you commit to a purchase.
Frequently Asked Questions
What is a cannula used for?
A cannula is used to deliver fluids, medication, blood, or oxygen into the body, or to drain fluid out. Common uses include IV therapy, oxygen delivery via nasal cannula, and minimally invasive cosmetic injections.
What's the difference between a cannula and a needle?
A needle is a rigid, sharp device generally used for a single puncture, while a cannula is a flexible tube that can remain in place for continued fluid or medication delivery, or that has a blunt tip for gentler tissue passage.
What gauge cannula is used for adults?
Adults commonly use 18G to 22G cannulas for routine IV fluids and medication, with larger gauges (14–16G) reserved for trauma or rapid transfusion, and smaller gauges (24–26G) used for fragile or difficult veins.
How long can an IV cannula stay in place?
This depends on clinical guidelines and the patient's condition, but many hospital protocols recommend reviewing and, if needed, replacing a peripheral IV cannula every 72–96 hours to reduce infection risk. Always follow your facility's specific protocol.
Are cannulas reusable?
No. Medical cannulas used for IV, oxygen, or injection purposes are single-use, sterile devices and should be disposed of safely after use to prevent contamination and infection.
How do I buy cannulas wholesale?
Buyers typically source cannulas wholesale through a certified medical supplier or distributor, such as OxyMed, that can provide bulk quantities, consistent stock, and documentation for regulatory compliance.