Osmolarity vs Fluid Volume in both the intracellular and extracellular spaces
Hypertonic, Hypotonic and Isotonic Solutions
HYPOTONIC-HYPERTONIC-ISOTONIC
SOLUTIONS
When patients experience deficient fluid volume, intravenous (IV) fluids are often prescribed. IV fluid restores fluid to the intravascular compartment, and some IV fluids are also used to facilitate the movement of fluid between compartments due to osmosis. There are three types of IV fluids: isotonic, hypotonic, and hypertonic.
Isotonic Solutions
Isotonic solutions are IV fluids that have a similar concentration of dissolved particles as blood. An example of an isotonic IV solution is 0.9% Normal Saline (0.9% NaCl). Because the concentration of the IV fluid is similar to the blood, the fluid stays in the intravascular space and osmosis does not cause fluid movement between compartments. for an illustration of isotonic IV solution administration with no osmotic movement of fluid with cells. Isotonic solutions are used for patients with fluid volume deficit (also called hypovolemia) to raise their blood pressure. However, infusion of too much isotonic fluid can cause excessive fluid volume (also referred to as hypervolemia).
What are the three types of isotonic solutions?
There are many different types of common isotonic fluids, such as: 1. Normal Saline (0.9% NaCl, NS)
2. 5% Dextrose in Water (D5W)
3. Lactated Ringer’s Solution (LR)
When Are Isotonic IV Fluids Given?
These fluids are useful when the patient has lost fluid volume from blood loss, trauma, or dehydration due to excessive nausea/vomiting or diarrhea.
Hypotonic solutions
A hypotonic tonic solution is any external solution that has a low solute concentration and high water concentration compared to body fluids. In hypotonic solutions, there is a net movement of water from the solution into the body.
A hypotonic solution has a lower solute concentration compared to the intracellular solute concentration. When a red blood cell is placed in a hypotonic solution, there will be a net movement of free water into the cell. This situation will result in an increased intracellular volume with a lower intracellular solute concentration. The solution will end up with a higher overall solute concentration. Under the microscope, the cell may appear engorged, and the cell membrane may eventually rupture. This overall process is known as cytolysis.
Note that osmosis is a dynamic equilibrium, so at any given moment, water molecular can momentarily flow toward any direction across the semipermeable membrane, but the overall net movement of all water molecules will be from an area of high free water concentration to an area of low free water concentration
What are some examples of Hypotonic Solutions, and why are they administered?
Sodium chloride 0.45% (1/2 NS), also known as half-strength normal saline, is a hypotonic IV solution used for replacing water in patients who have hypovolemia with hypernatremia
Examples of hypotonic solutions include 0.45% sodium chloride, 0.33% sodium chloride, 2.5% dextrose in water, and 0.2% sodium chloride.
0.33% Sodium Chloride Solution is used to allow kidneys to retain the needed amounts of water and is typically administered with dextrose to increase tonicity. It should be used in caution for patients with heart failure and renal insufficiency.
0.225% Sodium Chloride (0.225% NaCl)
0.225% Sodium Chloride Solution is often used as a maintenance fluid for pediatric patients as it is the most hypotonic IV fluid available at 77 mOsm/L. Used together with dextrose.
2.5% Dextrose in Water (D2.5W)
Another hypotonic IV solution commonly used is 2.5% dextrose in water (D2.5W). This solution is used to treat dehydration and decreased the levels of sodium and potassium. It should not be administered with blood products as it can cause hemolysis of red blood cells.
Nursing Considerations for Hypotonic IV Solutions
The following are the general nursing interventions and considerations when administering hypotonic IV solutions:
- Document baseline data. Before infusion, assess the patient’s vital signs, edema status, lung sounds, and heart sounds. Continue monitoring during and after the infusion.
- Do not administer in contraindicated conditions. Hypotonic solutions may exacerbate existing hypovolemia and hypotension causing cardiovascular collapse. Avoid use in patients with liver disease, trauma, or burns.
- Risk for increased intracranial pressure (IICP). Should not be given to patients with risk for IICP as the fluid shift may cause cerebral edema (remember: hypotonic solutions make cells swell).
- Monitor for manifestations of fluid volume deficit. Signs and symptoms include confusion in older adults. Instruct patients to inform the nurse if they feel dizzy.
- Warning on excessive infusion. Excessive infusion of hypotonic IV fluids can lead to intravascular fluid depletion, decreased blood pressure, cellular edema, and cell damage.
- Do not administer along with blood products. Most hypotonic solutions can cause hemolysis of red blood cells especially during rapid infusion of the solution. (Citation from Nurse Labs)
Hypertonic Solutions
Hypertonic Solutions
Hypertonic Solutions. Hypertonic solutions have a higher concentration of dissolved particles than blood. An example of hypertonic IV solution is 3% Normal Saline (3% NaCl). When infused, hypertonic fluids cause an increased concentration of dissolved solutes in the intravascular space compared to the cells.
When are Hypertonic Solutions Administered?
Clinicians use hypertonic fluids to increase intravascular fluid volume. Hypertonic saline can be utilized in the treatment of hyponatremia. Hypertonic saline and mannitol are both indicated to reduce intracranial pressure.
What are some types of Hypertonic Fluids?
Hypertonic Solutions
- 3% NaCl (normal saline/sodium chloride)
- 5% NaCl – normal saline/sodium chloride.
- D10W – Dextrose 10% in Water.
- D20W – Dextrose 20% in Water.
- D50W – Dextrose 50% in Water.
Selection of IV Catheters and Sites
Selection of Catheters and Sites (Citation from CDC)
- In adults, use an upper-extremity site for catheter insertion. Replace a catheter inserted in a lower extremity site to an upper extremity site as soon as possible.
- In pediatric patients, the upper or lower extremities or the scalp (in neonates or young infants) can be used as the catheter insertion site.
- Select catheters on the basis of the intended purpose and duration of use, known infectious and non-infectious complications (e.g., phlebitis and infiltration), and experience of individual catheter operators.
- Avoid the use of steel needles for the administration of fluids and medication that might cause tissue necrosis if extravasation occurs.
- Use a midline catheter or peripherally inserted central catheter (PICC), instead of a short peripheral catheter, when the duration of IV therapy will likely exceed six days.
- Evaluate the catheter insertion site daily by palpation through the dressing to discern tenderness and by inspection if a transparent dressing is in use. Gauze and opaque dressings should not be removed if the patient has no clinical signs of infection. If the patient has local tenderness or other signs of possible CRBSI, an opaque dressing should be removed and the site inspected visually.
- Remove peripheral venous catheters if the patients develops signs of phlebitis (warmth, tenderness, erythema or palpable venous cord), infection, or a malfunctioning catheter.
. Education, Training and Staffing
Educate healthcare personnel regarding the indications for intravascular catheter use, proper procedures for the insertion and maintenance of intravascular catheters, and appropriate infection control measures to prevent intravascular catheter-related infections
- Periodically assess knowledge of and adherence to guidelines for all personnel involved in the insertion and maintenance of intravascular catheters.
- Designate only trained personnel who demonstrate competence for the insertion and maintenance of peripheral and central intravascular catheters.
- Ensure appropriate nursing staff levels in ICUs. Observational studies suggest that a higher proportion of “pool nurses” or an elevated patient–to-nurse ratio is associated with CRBSI in ICUs where nurses are managing patients with CVCs.
Hand Hygiene and Aseptic Technique
- Perform hand hygiene procedures, either by washing hands with conventional soap and water or with alcohol-based hand rubs (ABHR). Hand hygiene should be performed before and after palpating catheter insertion sites as well as before and after inserting, replacing, accessing, repairing, or dressing an intravascular catheter. Palpation of the insertion site should not be performed after the application of antiseptic, unless aseptic technique is maintained.
- Maintain aseptic technique for the insertion and care of intravascular catheters.
- Wear clean gloves, rather than sterile gloves, for the insertion of peripheral intravascular catheters, if the access site is not touched after the application of skin antiseptics.
- Sterile gloves should be worn for the insertion of arterial, central, and midline catheters.
- Use new sterile gloves before handling the new catheter when guidewire exchanges are performed.
- Wear either clean or sterile gloves when changing the dressing on intravascular catheters.
Maximal Sterile Barrier Precautions
- Use maximal sterile barrier precautions, including the use of a cap, mask, sterile gown, sterile gloves, and a sterile full body drape, for the insertion of CVCs, PICCs, or guidewire exchange.
- Use a sterile sleeve to protect pulmonary artery catheters during insertion.
- Prepare clean skin with an antiseptic (70% alcohol, tincture of iodine, an iodophor or chlorhexidine gluconate) before peripheral venous catheter insertion.
- Prepare clean skin with a >0.5% chlorhexidine preparation with alcohol before central venous catheter and peripheral arterial catheter insertion and during dressing changes. If there is a contraindication to chlorhexidine, tincture of iodine, an iodophor, or 70% alcohol can be used as alternatives.
- No comparison has been made between using chlorhexidine preparations with alcohol and povidone-iodine in alcohol to prepare clean skin. Unresolved issue
- No recommendation can be made for the safety or efficacy of chlorhexidine in infants aged <2 months. Unresolved issue
- Antiseptics should be allowed to dry according to the manufacturer’s recommendation prior to placing the catheter.
Catheter Site Dressing Regimens
- Use either sterile gauze or sterile, transparent, semipermeable dressing to cover the catheter site.
- If the patient is diaphoretic or if the site is bleeding or oozing, use gauze dressing until this is resolved.
- Replace catheter site dressing if the dressing becomes damp, loosened, or visibly soiled.
- Do not use topical antibiotic ointment or creams on insertion sites, except for dialysis catheters, because of their potential to promote fungal infections and antimicrobial resistance.
- Do not submerge the catheter or catheter site in water. Showering should be permitted if precautions can be taken to reduce the likelihood of introducing organisms into the catheter (e.g., if the catheter and connecting device are protected with an impermeable cover during the shower).
- Replace dressings used on short-term CVC sites every 2 days for gauze dressings.
- Replace dressings used on short-term CVC sites at least every 7 days for transparent dressings, except in those pediatric patients in which the risk for dislodging the catheter may outweigh the benefit of changing the dressing.
- Replace transparent dressings used on tunneled or implanted CVC sites no more than once per week (unless the dressing is soiled or loose), until the insertion site has healed.
- No recommendation can be made regarding the necessity for any dressing on well-healed exit sites of long-term cuffed and tunneled CVCs. Unresolved issue
- Ensure that catheter site care is compatible with the catheter material.
- Use a sterile sleeve for all pulmonary artery catheters.
Recommendation Update [July 2017] For patients aged 18 years and older:
- Chlorhexidine-impregnated dressings with an FDA-cleared label that specifies a clinical indication for reducing catheter-related bloodstream infection (CRBSI) or catheter-associated bloodstream infection (CABSI) are recommended to protect the insertion site of short-term, non-tunneled central venous catheters.
(See Updated Recommendations on Chlorhexidine-Impregnated Dressings, Section 5.0 Implementation Considerations for Patients Aged 18 Years and Older).
[Superseded 2011 Recommendation] Use a chlorhexidine-impregnated sponge dressing for temporary short-term catheters in patients older than 2 months of age if the CLABSI rate is not decreasing despite adherence to basic prevention measures, including education and training, appropriate use of chlorhexidine for skin antisepsis.
Recommendation Update [July 2017] For patients younger than 18 years:
- Chlorhexidine-impregnated dressings are NOT recommended to protect the site of short-term, non-tunneled central venous catheters for premature neonates due to risk of serious adverse skin reactions. [Superseded 2011 Recommendation] No recommendation is made for other types of chlorhexidine dressings. Unresolved issue
- No recommendation can be made about the use of chlorhexidine-impregnated dressings to protect the site of short-term, non-tunneled central venous catheters for pediatric patients less than 18 years old and non-premature neonates due to the lack of sufficient evidence from published, high-quality studies about efficacy and safety in this age group. Unresolved issue
Monitor the catheter sites visually when changing the dressing or by palpation through an intact dressing on a regular basis, depending on the clinical situation of the individual patient. If patients have tenderness at the insertion site, fever without obvious source, or other manifestations suggesting local or bloodstream infection, the dressing should be removed to allow thorough examination of the site.
Encourage patients to report any changes in their catheter site or any new discomfort to their provider.
. Patient Cleansing
- * Use a 2% chlorhexidine wash for daily skin cleansing to reduce CRBSI
Catheter Securement Devices
- * Use a sutureless securement device to reduce the risk of infection for intravascular catheters
- Antimicrobial/Antiseptic Impregnated Catheters and Cuffs
- * Use a chlorhexidine/silver sulfadiazine or minocycline/ rifampin -impregnated CVC in patients whose catheter is expected to remain in place >5 days if, after successful implementation of a comprehensive strategy to reduce rates of CLABSI, the CLABSI rate is not decreasing. The comprehensive strategy should include at least the following three components: educating persons who insert and maintain catheters, use of maximal sterile barrier precautions, and a >0.5% chlorhexidine preparation with alcohol for skin antisepsis during CVC insertion *
Antibiotic/Antiseptic Ointments
- * Use povidone iodine antiseptic ointment or bacitracin/ gramicidin/polymyxin B ointment at the hemodialysis catheter exit site after catheter insertion and at the end of each dialysis session only if this ointment does not interact with the material of the hemodialysis catheter per manufacturer’s recommendation.
Antibiotic Lock Prophylaxis, Antimicrobial Catheter Flush and Catheter Lock Prophylaxis
- * Use prophylactic antimicrobial lock solution in patients with long term catheters who have a history of multiple CRBSI despite optimal maximal adherence to aseptic technique.
Anticoagulants
- * Do not routinely use anticoagulant therapy to reduce the risk of catheter-related infection in general patient populations
Replacement of Peripheral and Midline Catheters
- There is no need to replace peripheral catheters more frequently than every 72–96 hours to reduce risk of infection and phlebitis in adults.
- No recommendation is made regarding replacement of peripheral catheters in adults only when clinically indicated Unresolved issue
- Replace peripheral catheters in children only when clinically indicated.
- Replace midline catheters only when there is a specific indication.
- 1. No recommendation can be made regarding the length of time a needle used to access implanted ports can remain in place. Unresolved issue
Needleless Intravascular Catheter Systems
- Change the needleless components at least as frequently as the administration set. There is no benefit to changing these more frequently than every 72 hours.
- Change needleless connectors no more frequently than every 72 hours or according to manufacturers’ Recommendations for the purpose of reducing infection rates.
- Ensure that all components of the system are compatible to minimize leaks and breaks in the system.
- Minimize contamination risk by scrubbing the access port with an appropriate antiseptic (chlorhexidine, povidone iodine, an iodophor, or 70% alcohol) and accessing the port only with sterile devices.
- Use a needleless system to access IV tubing.
- When needleless systems are used, a split septum valve may be preferred over some mechanical valves due to increased risk of infection with the mechanical valves.
