2.2 Patient Care in Special Populations & Infection Control

Patient Care in Special Populations & Infection Control

Providing high-quality care in nuclear medicine requires adapting procedures and communication styles to accommodate the unique needs of special populations, particularly pediatric and geriatric patients. Furthermore, rigorous infection control practices are non-negotiable to protect both the patient and the healthcare worker, especially given the handling of blood products and intravenous radiopharmaceuticals.

Pediatric Care and Dose Scaling

Pediatric patients are not simply miniature adults. They possess different physiological parameters, metabolic rates, and psychological needs. A primary concern in pediatric nuclear medicine is minimizing radiation exposure (ALARA) while ensuring diagnostic image quality.

Pediatric Dose Scaling

Because children are smaller and have different biodistribution kinetics, adult radiopharmaceutical dosages must be mathematically scaled down. Administering an adult dose to a child results in an unacceptably high radiation burden.

Common methods for dose scaling include:

1. Body Surface Area (BSA) Method: Often considered the most accurate method for scaling doses as it correlates well with physiological parameters like blood volume and glomerular filtration rate.
   • Formula: Pediatric Dose = (Patient BSA / 1.73 m^2) × Adult Dose
2. Webster's Rule: A rule based on the child's age.
   • Formula: Pediatric Dose = [(Age + 1) / (Age + 7)] × Adult Dose
3. Young's Rule: Another age-based formula.
   • Formula: Pediatric Dose = [Age / (Age + 12)] × Adult Dose
4. Clark's Rule: Based on the child's weight in pounds.
   • Formula: Pediatric Dose = (Weight in lbs / 150) × Adult Dose

Note: Modern practice heavily favors weight-based or BSA-based dosing over purely age-based rules, and institutions typically have standardized, approved pediatric dose charts.

Pediatric Communication and Immobilization

• Communication: Explain procedures using age-appropriate language. Avoid alarming words (e.g., use "picture camera" instead of "radiation scanner"). Involve parents to help soothe the child.
• Immobilization: Children may struggle to remain still for lengthy scans. Mechanical immobilization devices (papoose boards, sandbags, Velcro straps) can be used, but must be applied safely and with parental consent. In some cases, mild sedation may be required, which necessitates specialized nursing or anesthesia support and rigorous monitoring.

Geriatric Care Considerations

The geriatric population presents distinct challenges due to the physiological changes associated with aging.

Key Considerations:

• Communication: Hearing loss (especially high-frequency) is common. Speak clearly, face the patient (allowing them to read lips and expressions), lower the pitch of your voice, and minimize background noise. Do not shout.
• Skin Integrity and Fall Risk: Aging skin is thin, fragile, and prone to tearing (skin tears). Use extreme care when transferring patients, applying tourniquets, or removing adhesive tape. Ensure the patient is never left unattended on a narrow imaging table, as fall risk is elevated.
• Positioning: Conditions like kyphosis, arthritis, and joint replacements can make standard imaging positions painful or impossible. Utilize pillows and sponges to provide support and maximize comfort during long static acquisitions.
• Polypharmacy: Older adults often take multiple medications. Be vigilant regarding drug interactions that might alter the biodistribution of radiopharmaceuticals or interfere with pharmacological stress testing.

Infection Control: Standard Precautions and Hand Hygiene

Infection control is critical to prevent Healthcare-Associated Infections (HAIs).

Standard Precautions

Standard precautions are the minimum infection prevention practices that apply to all patient care, regardless of suspected or confirmed infection status. The core principle is that all blood, body fluids, secretions, excretions, non-intact skin, and mucous membranes may contain transmissible infectious agents.

Hand Hygiene

Hand hygiene is the single most effective way to prevent the spread of infection.

• Alcohol-Based Hand Rub (ABHR): Preferred method in most clinical situations when hands are not visibly soiled.
• Soap and Water: Must be used when hands are visibly soiled, after caring for patients with known or suspected infectious diarrhea (e.g., Clostridioides difficile), and after suspected exposure to spore-forming pathogens.

Personal Protective Equipment (PPE)

PPE selection under standard precautions is driven by the anticipated interaction:

• Gloves: When touching blood, body fluids, mucous membranes, or non-intact skin.
• Gowns: During procedures that are likely to generate splashes or sprays of blood or body fluids.
• Masks/Eye Protection (Goggles/Face Shields): During activities likely to generate splashes or sprays to the face.

Aseptic Technique in the Radiopharmacy

Nuclear medicine technologists routinely elute generators, compound kits, and draw patient doses. Because these radiopharmaceuticals are administered intravenously, they must be strictly sterile.

Aseptic technique is a set of specific practices and procedures performed under carefully controlled conditions with the goal of minimizing contamination by pathogens.

• Environment: Compounding occurs in a laminar flow hood (ISO Class 5 environment) which provides HEPA-filtered air.
• Materials: Sterile syringes, needles, and vials must be used. Vials must be swabbed with 70% isopropyl alcohol and allowed to dry prior to puncture.
• Handling: The technologist must never touch the needle shaft or the sterile plunger of the syringe. Strict adherence to USP <797> and <825> guidelines is mandatory.

Transmission-Based Isolation Precautions

When a patient is known or suspected to be infected with highly transmissible pathogens, additional precautions are implemented alongside standard precautions.

1. Contact Precautions:

   • Used for: Pathogens spread by direct or indirect contact (e.g., MRSA, VRE, C. difficile).
   • PPE required: Gown and gloves upon entering the room.
   • Equipment: Use disposable or dedicated patient-care equipment. Disinfect cameras thoroughly after use.

2. Droplet Precautions:

   • Used for: Pathogens transmitted through large respiratory droplets generated by coughing, sneezing, or talking (e.g., Influenza, Pertussis, Meningococcus).
   • PPE required: Surgical mask upon entering the room.
   • Patient transport: The patient should wear a surgical mask during transport to the nuclear medicine department.

3. Airborne Precautions:

   • Used for: Pathogens transmitted via small droplet nuclei that remain infective over time and distance in the air (e.g., Tuberculosis, Measles, Varicella).
   • Environment: Airborne Infection Isolation Room (AIIR) with negative air pressure.
   • PPE required: NIOSH-approved N95 respirator or higher (PAPR) donned prior to room entry.
   • Patient transport: Patient must wear a surgical mask (not an N95) during transport. Procedures should be delayed if not emergent.