CMT Medical Procedures and Techniques 2 — Questions and Answers
Question 1: When performing venipuncture, the tourniquet should be applied how far above the intended site?
- 1-2 inches
- 3-4 inches (Correct answer)
- 6-8 inches
- 10-12 inches
Correct answer: 3-4 inches
The tourniquet should be placed 3-4 inches (7-10 cm) above the intended venipuncture site.
Proper tourniquet placement is 3-4 inches above the planned puncture site. The tourniquet should be tight enough to impede venous return but not so tight as to occlude arterial flow—the radial pulse should remain palpable. Maximum application time is one minute; prolonged tourniquet time causes hemoconcentration, falsely elevating results for proteins, electrolytes, and cell counts. For antecubital fossa draws, the tourniquet is placed on the upper arm. If veins are difficult to find, having the patient make a fist, applying warm compresses, or lowering the arm can help distend veins.
Question 2: The correct angle for an intramuscular (IM) injection is:
- 15 degrees
- 45 degrees
- 90 degrees (Correct answer)
- 5 degrees
Correct answer: 90 degrees
Intramuscular injections are administered at a 90-degree angle to ensure the needle reaches the muscle tissue.
IM injections are given at 90 degrees to the skin surface, inserting the needle quickly and firmly into the muscle. Common IM sites include the vastus lateralis (preferred for infants), deltoid (preferred for adults for small-volume injections), and ventrogluteal (preferred for larger volumes in adults). Needle gauge and length depend on patient size and site: typically 22-25 gauge, 1-1.5 inches for adults. The Z-track technique is recommended for all IM injections to prevent medication from tracking back through subcutaneous tissue. Aspirating before injection is no longer recommended by the CDC for most IM injections.
Question 3: When applying a bandage to an extremity, which direction should wrapping proceed?
- Proximal to distal
- Distal to proximal (Correct answer)
- Direction does not matter
- Only in a circular pattern
Correct answer: Distal to proximal
Bandages should be wrapped from distal to proximal (away from the heart toward the heart) to promote venous return.
Wrapping distal to proximal ensures that venous blood flow is directed toward the heart rather than being trapped distally, which could cause swelling, pain, or tissue damage. The bandage should be applied firmly but not so tightly that it impairs circulation. After application, check the 5 Ps: Pain, Pallor, Pulselessness, Paresthesia (numbness/tingling), and Paralysis. Fingers or toes distal to the bandage should remain warm with brisk capillary refill (less than 2 seconds). Spiral, figure-eight, and recurrent bandage techniques are used depending on the body part.
Question 4: The preferred site for checking a pulse in an unresponsive adult patient is the:
- Radial artery
- Carotid artery (Correct answer)
- Brachial artery
- Femoral artery
Correct answer: Carotid artery
The carotid artery in the neck is the preferred pulse check site for unresponsive adults because it is large, central, and accessible.
The carotid artery is preferred for unresponsive patients because it is a central artery that maintains perfusion even when peripheral pulses become weak or undetectable due to low blood pressure. To check, place two fingers (never the thumb) in the groove between the trachea and the sternocleidomastoid muscle. For infants under one year, the brachial artery (inner upper arm) is used because their short, fat necks make carotid palpation difficult. The radial artery (wrist) is the standard site for conscious patients' routine pulse assessment.
Question 5: When collecting a blood specimen, which tube should be drawn first using the order of draw?
- Lavender top (EDTA)
- Blue top (sodium citrate)
- Blood culture bottles (Correct answer)
- Green top (heparin)
Correct answer: Blood culture bottles
Blood culture bottles are always drawn first to minimize contamination risk, followed by the standard order of draw.
The CLSI-recommended order of draw prevents cross-contamination between tube additives: (1) Blood cultures (sterile), (2) Light blue (sodium citrate—coagulation), (3) Red/gold (serum—no additive or clot activator), (4) Green (heparin—chemistry), (5) Lavender (EDTA—hematology), (6) Gray (sodium fluoride/oxalate—glucose). Drawing out of order can cause additive carryover; for example, EDTA contamination in a blue top falsely elevates PT/INR results. For syringe draws, blood cultures still go first. The mnemonic 'Boys Love Red Green Lovely Gray' helps remember the sequence.
Question 6: What is the maximum time a tourniquet should remain applied during blood collection?
- 30 seconds
- 1 minute (Correct answer)
- 3 minutes
- 5 minutes
Correct answer: 1 minute
A tourniquet should not remain in place for more than one minute to prevent hemoconcentration and inaccurate test results.
The one-minute maximum tourniquet time is a critical phlebotomy standard. Prolonged venous stasis causes hemoconcentration—water and small molecules filter out of distended veins into surrounding tissue, artificially elevating concentrations of large molecules (proteins, lipids, cell counts, calcium, iron). Potassium levels can rise significantly as cells become hypoxic. If the tourniquet is on too long, release it for 2 minutes before reapplying. For lactic acid and ionized calcium tests, specimens should ideally be collected without a tourniquet or with minimal tourniquet time.
CMT Medical Procedures and Techniques 2
When performing venipuncture, the tourniquet should be applied how far above the intended site?