From the Guidelines
Smaller needle sizes, specifically 25-30 gauge, are recommended for minimal discomfort during medical procedures, as they create smaller puncture wounds and stimulate fewer pain receptors. The relationship between needle size and pain perception is based on the diameter of the needle, with larger gauge numbers indicating thinner needles that cause less pain 1. For example, a study published in Alzheimer's and Dementia in 2022 found that small-bore needles (≥24 gauge) are associated with lower rates of headache, back pain, and discomfort, as well as a lower risk of blood contamination and CSF leakage 1.
When it comes to specific medical procedures, such as lumbar puncture, the use of atraumatic narrow-bore (≥22-gauge) needles is recommended to reduce the risk of adverse events 1. Additionally, the selection of a specific type of needle should aim to minimize discomfort and the risk of complications, taking into account the patient's age, weight, and the purpose of the procedure 1.
Beyond needle size, other factors can influence pain perception during medical procedures, including:
- Using sharp, new needles
- Applying topical anesthetics like lidocaine 4% cream 30 minutes before the procedure
- Injecting medication slowly
- Ensuring the medication is at room temperature
- Using distraction techniques and communicating clearly with patients about what to expect, as anxiety can heighten pain perception during needle procedures 1.
It's also important to note that the injection technique matters significantly, with approaches at a 45-90 degree angle for intramuscular injections and 10-15 degrees for subcutaneous injections typically minimizing discomfort 1. Overall, the goal is to minimize pain and discomfort while ensuring the safe and effective administration of medical procedures.