Note: I am an Emergency Medical Technician with 18 years Emergency Ambulance work. This information is intended as a guide only; you should seek professional advice at all times. Information was gained from personal experience and training, interviewing an Intermediate Life Support Paramedic, and utilizing the excellent textbook: Emergency Care in the Streets (Nancy Caroline MD, “The Mother of Paramedics”).
The human body is mostly water, made up of Intracellular Fluid (fluid inside the body cells, which can account for approximately 45% of body weight), Extracellular Fluid (fluid outside the cells, which accounts for approximately 15% of body weight). Extracellular fluid is further divided into Interstitial Fluid and includes Cerebrospinal Fluid (brain and spinal cord fluid) and intraocular fluid (eyeball fluid).
A normal healthy person is considered hemodynamically stable; meaning the person has good blood flow (circulation). However, fluid loss from burns, bleeding (internal and external), vomiting, Diarrhoea, anaphylactic shock, cardiogenic shock, heat stroke, and neurological shock results in a patient becoming hemodynamically unstable due to the disruption of blood circulation.
Disrupting Hemodynamic Balance
Blood loss is the most obvious method of causing hemodynamic unstable conditions. As blood leaves the body, so does the body’s ability to transfer fluids to the needed organs and tissue. More specifically, blood loss limits the amount of oxygen to vital organs, tissues, and cells. Blood loss can be caused by a bullet wound, a severed limb, large cut / wound, or internal bleeding.
Shock, also known as circulatory shock, is a medical condition, not an emotional response. A person can be “shocked” after being frightened (an emotional response), but this type of shock will not kill you (normally). Circulatory shock, normally due to an injury, is the result of the inadequate flow of fluids within the body’s circulatory system. Circulatory shock is a life-threatening medical emergency, and one of the most common causes of death for critically ill people or those who have suffered a major traumatic injury. Signs of shock include: low blood pressure, rapid heartbeat, shallow breathing, low urine output, confusion, cool-clammy skin, thirst, and loss of consciousness.
Dehydration is defined as inadequate, total systemic (involves whole body), fluid volume and is usually a chronic condition in the elderly or very young, or individuals not consuming adequate amounts of water. Dehydration may take days to show. The body reacts to the fluid loss by shifting fluid around to compensate; however this results in a total system deficit. Signs and symptoms of Dehydration include dry mucosa, brown dry tongue and decreased skin turgor, loss of elasticity, which are the early and more obvious signs. Worsening signs are decreasing level of consciousness, rapid heart rate, rapid breathing, flushed dry skin, and postural hypotension (condition of low blood pressure when standing or sitting – symptoms resolve when laid flat). Causes include diarrhoea, bleeding, insufficient fluid, and food intake.
Overhydration is when the body’s total systemic fluid volume increases; the fluid fills vascular compartments, moves into the interstitial compartment, and then is forced into the intracellular compartment. Over-hydration can lead to death. Signs and symptoms include shortness of breath, puffy eyelids, swelling of the extremities and then the whole body, increased urine output, and acute weight gain. Causes include unattended IVs, kidney failure, and some cardiac conditions.
First Aid and the Replacement of Fluid
If an individual is wounded, the first step is to conduct first aid to assess the individual.
Bleeding - Stop the loss of blood with direct pressure and dressings. Bleeding internal bleeding requires surgery.
Vomiting and diarrhea – Is usually caused by food poisoning, poisoning, or just being unwell. Whichever the cause, you need to determine the correct method of treating the issue (anti-diarrhea medications for example).
Burns – Requires cooling and covering.
Anaphylactic Shock – Requires adrenalin and antihistamines.
The easiest way to replace fluid is to give an electrolyte solution by mouth. You can purchase electrolyte fluids, or make your own. The United Nations’ recipe consists of 6 level teaspoons of sugar and ½ level teaspoon of salt dissolved in 1 liter (approximately 33 ounces) of clean water. It is important to get the measurements of sugar and salt correct; as too much or too little can cause damage.
Sometimes the patient will not be able to drink fluid, due to nausea, vomiting, facial injuries , etc. Your next option is to give fluid by IV (Intravenous or “within a vein”) or IO (Intraosseous or “within the bone”). The IO method is a specialized technique involving a drill or special needle, and will not be discussed in this article. Administering an IV is the most common method for medical professionals, and is the most practical for the preparedness community.
The most common IV fluid is 0.9% Sodium Chloride (NaCl), which is Isotonic, or the same sodium concentration as body fluids. This means it expands the vascular fluid without severe fluid shifts which can cause other issues. Care must be taken to remember that NaCl does not carry oxygen; it only expands the volume available with a short timeframe; around 20 minutes. So, effectively you are diluting any blood left in the circulatory system which means oxygen transport is limited (blood has Haemoglobin molecules which carries oxygen). NaCl does have the advantage of being compatible with most drugs; therefore an infusion of medication can be made by mixing the required concentration of medication in the IV bag and giving it over a period of time.
Administering an IV is not a case of shoving a needle in the patients arm, and pouring fluid into them (contrary to some TV shows). Administering an IV is a dangerous undertaking due to the fact you are performing an invasive procedure; a lack of knowledge and/or improper technique can cause significant harm to the patient. Here are some of the dangers:
1. In worst case scenarios, the patient can have an allergic reaction to the IV components or some fluids; there can be sudden elevations in their temperature (pyrogenic reaction).
2. There are issues in placing an IV (1) you can go completely through the vein causing bleeding, (2) the vein can “tissue” when you try and flush it, (3) you can cause Thrombophlebitis (inflammation of the veins), and (4) you can also end up against the valves in the veins which can stop you from being successful with your IV attempt.
3. Catheter shear can also occur when the cannula slides forward over the end of the needle. If this occurs DO NOT pull the cannula back over the needle as you can shear micro pieces of the plastic, which if introduced into the veins will cause an embolism (blockage) to occur.
4. Care must be taken not to introduce air into the IV line, although most patients can tolerate some air in their veins (Caroline, 2008).
5. Some IV fluids are toxic to the veins, glucose 10% and 5% are good example of fluids that can damage a vein (glucose is corrosive to the vein).
6. A patient with a head injury will be worse off if their blood pressure is raised too high, due to fluid replacement; it can also cause further damage in patients with cerebral injuries (strokes).
7. Additional fluid can cause a patient with heart failure to deteriorate or can dislodge any clots formed on internal bleeding sites.
Hence there is a need to be very careful when putting fluid into a patient and should only be done by an appropriately trained person. There is a move away from fluid overloading, or giving fluid to every patient, as there is evidence that too much fluid can be detrimental to the patient’s long term recovery. Blood carries oxygen, while IV fluids do not. It is becoming accepted practice to allow a patient to remain slightly hypotensive (low blood pressure), or they titrate (concentrate) the fluid to maintain Blood Pressure; which will in most situations reduce the effects of fluid overload on the heart and body systems, this is called “permissive hypotension”.
IV Supplies, Required and Optional
The required items to administer an IV include: cannulas, IV fluid, an alcohol swab, the giving set (or IV administration set), a dressing, and tape. Optional items include Saline Locks, Saline Flush, and IV Dressings.
A venous cannula, or catheter, is inserted into a vein, primarily for the administration of intravenous fluids, for obtaining blood samples, and for administering medicines. The two most common types are the over the needle catheter and butterfly catheter. Most commonly used in pre-hospital settings are the over the needle type catheters. These are a Teflon catheter placed over a needle which is inserted into a vein and the needle withdrawn leaving the catheter in the vein.
The advantages for the over the needle catheter include (1) less likely to go through the vein compared to a butterfly cannula, (2) it’s more comfortable when in place, and (3) requires less limb immobilization than the butterfly catheter. Its disadvantages include needle stick risk, it’s more difficult to place, and it’s possible to shear the catheter on the needle. This article will deal only with the over the needle catheters referred to Cannulas for the rest of this article.
The catheters come in different sizes as labelled by size and color on the packet, 24 gauge (g), 22g, 20g, 18g, 16g and 14g are the most likely sizes found in the pre-hospital setting; however you may find 12g sized catheters used for chest decompression. When discussing gauge sizes, the greater the number, the smaller the needle/catheter (24g is a much smaller than a 16g).
Always use the best sized catheter to fit the vein you want to administer the IV; children would be 24g, 22g and 20g. Adults requiring medication would have a 20g or 18g, fluid replacement requires an 18g or above (18g, 16g, or 14g).
When choosing a site to administer an IV, start at the distal (furthest from center) and work up the extremity. Patient’s feet have been used when access to limbs is not possible; don’t be afraid to look at all areas for cannulation.
The adult hand would take a 20g easily (larger sizes can be uncomfortable), and the interior elbow (anticubital vein) would take a 14g, 16g, or 18g.
When administering an IV in a child, it will be necessary to have some form of local anaesthetic gel or patch available; as it will make the administration go a lot smoother for you.
The most common type of IV fluid, as discussed earlier, is 0.9% Sodium Chloride (NaCl). IV fluid is contained in a bag, which is located inside a protective package. Before opening the protective bag, squeeze the bag to check for leaks (if it leaks get another one). Check the expiry date. Next, Open the outer layer and hold the bag to the light to check for debris or discoloration (if either is present then discard the bag). On the bottom of the bag will be a colored plastic cap and a port, the plastic cap protects the opening for the spike on the Giving set and the port allows for medication to be added to the bag.
The Giving Set (IV Administration Line Set)
The Giving Set, or IV administration line set, is a tube arrangement with consists of a spiked chamber at one end, a roller crimp, a medication port (optional), and a threaded attachment end. The giving set is used to connect a bag of IV fluid to the cannula, allows adjustment of the flow rate using the roller wheel, and administration of medications through the medication port. When selecting IV administration line sets, you need to understand the different drip or flow rates. The drip rate is usually found on the outside of the packet, this tells you how many drops for a milliliter of fluid to pass through the orifice and into the drip chamber.
Most sets come as Microdrip and Macrodrip sets; Microdrip sets are good for children as the flow rates can be well controlled, Macrodrip sets are better for fluid replacement. A way to avoid fluid overload is to use a Volutrol or Buterol Microdrip set which has a chamber with either 100ml or 200ml volume calibrated chamber which allows a specific amount of fluid to be given over time.
Isopropyl Alcohol Swab
Alcohol is used to clean the skin around the IV site prior to administration, to prevent contamination.
Pressure dressings can be a piece of gauze or small dot shaped dressings, which are used to provide direct pressure to the IV site if the cannula is withdrawn for whatever reason (failed IV attempt).
Tape is used to provide additional security to the IV line so that it does not pull out of the vein.
Saline Locks and Saline Flush (Optional)
Saline Locks, also known as Leur Locks, fit on the end of the cannula to stop the blood from congealing and blocking the IV line. While they are optional, Saline Locks are highly recommended, as they create a seal whenever the main IV line is removed from the catheter. This seal reduces the possibility of cross contamination, and protects the patient’s catheter from contamination that can lead to infections. Saline Locks can also be used for direct administration of medication into the veins. There are several types of saline locks on the market, and can include needle or needless, and some may have extension tubes and connectors.
Flushing the IV line or saline lock with saline (saline flush) will ensure the IV is still in patient, and will ensure no cl. Additionally, flushing the line after medications are delivered ensures the medication was fully administered to the patient.
IV Dressing (Optional)
A multipart dressing designed to protect and secure the IV site to the patient. An IV dressing may have a date label on it, as IVs must be replaced regularly in long term care situations. Generally IV administered pre-hospital need replacing; as they are usually administered under less than ideal situations.
IV Administration Kit (an alcohol swab, gauze, tape, tourniquet, and IV Dressing)
For work, my standard Ambulance issue is an IV roll with enough supplies to administer up to four IVs. We carry an additional IV roll in the vehicle, and a complete replacement set in the lockers; as we never know when we will be able to restock. My recommendation is to include a minimum of two IV sets in your large trauma kit, which can be carried or packed inside of your vehicle. For your home clinic / Bug Out clinic, I would include a similar set up but with 10 IV sets; or as much IV gear as you can afford. The key here is to ensure you have the correct sized catheters for your family and/or group members. Also, have a large supply of fluids.
Thank you for reading our introduction to IV’s. We will produce a handout at a later time, which will cover the act of administering an IV. Until then, please look at our recommended YouTube videos.
Download our Handout: Introduction to IV Administration