Water Chemistry: Osmosis and Osmotic Pressure

Water Chemistry

• Movement of water (solvent) from area with high concentration to area with low concentration (high to low)
• Osmosis: movement of water from area with more water to area with less water
• Osmotic Pressure: ability of osmosis to generate enough pressure to move a volume of water
• Isotonic: same osmotic pressure; cells placed in isotonic solution have no net gain or loss of water
• Hypertonic: higher osmotic pressure; cells placed in hypertonic solution lose water
• Hypotonic: lower osmotic pressure; cells placed in hypotonic solution gain water

Modes of Transmission

• Contact: most common mode of transmission
• Direct: transferred via person to person (e.g. shaking hands)
• Indirect: transferred between individuals and contaminated surfaces/fomites
• Droplet: involves contact of mucous membranes (nose, mouth, eyes)
• Examples: influenza, COVID, respiratory viruses
• Airborne: occurs when airborne particles remain suspended in the air
• Examples: Chickpox, measles, tuberculosis
• Vehicle: contaminated food or water supply
• Vector: animals or insects that carry and spread disease (e.g. mosquitoes)

Hand Hygiene

• Single most important measure for preventing HAIs in patients and staff
• Ideal times for hand hygiene (HH):
• When entering or exiting the hospital
• After handling blood or body fluids
• When hands are visibly soiled
• Between contact with patients or equipment
• Between procedures involving clean and dirty equipment
• Before preparing or handling sterile products
• Includes washing hands with soap and water when visibly soiled, and using ABHR at other times

Personal Protective Equipment (PPE)

• Gloves:
• Appropriate for the task
• Fluid-resistant
• Designed to protect staff from exposure to contaminated fluids
• Long enough to cover wrists and forearms
• Sufficient thickness to be highly tear-resistant
• Gowns:
• Protect staff from splashes or sprays of blood, body fluids, or chemicals
• If reusable, must be laundered in accordance with CAN/CSA Z314 standards
• Must be impervious (fluid-resistant) and fireproof
• Face and Eye Protection:
• Mask/Face Protection: may be used in addition to eye protection
• Eye Protection: used in addition to mask when there is a risk of splashes or sprays
• Respirator:
• Blocks at least 95% of airborne particles if properly fitted
• Requires fit-testing
• Not designed for children or people with facial hair
• Not typically used in MDRD

PPE – Selection and Use

• Selected according to the degree of risk to exposure
• Avoid contact between contaminated PPE and clean surfaces, clothing, or unsuspecting individuals
• Soiled PPE must be discarded in an appropriate manner
• Do not share PPE
• Remove PPE completely and clean hands at the end of the shift
• Gloves should be clean, non-sterile, and changed between tasks or procedures; never reused
• Face/eye protection should be well-fitted around the nose and eyes
• Long-sleeved gowns should be impervious to protect skin and clothing
• PPE does not replace the need for adherence to basic infection prevention and control practices and policies

This quiz covers the concept of osmosis, osmotic pressure, and passive transport in water chemistry, including isotonic, hypertonic, and hypotonic solutions.