Physical Exam Parameters
In veterinary medicine, fluid administration is one of the most essential measures for patient management. It helps replace the fluids and electrolytes lost due to an underlying disease. However, the fluids must be delivered in specific amounts, methods, types, and rates based on the deficit assessed in each patient, necessitating a physical examination.
This exam reveals the variables of percentage dehydration and body weight, which are used to calculate the degree of dehydration using a specific hydration deficit formula discussed later. Also, three main aspects are considered in determining the fluid administration method. These include the patient’s clinical condition, the extent of dehydration, and the required rate of rehydration (Naden, 2020). As such, the routes of fluid administration include oral, intravenous, intraperitoneal, subcutaneous, intramedullary, and rectal.
For intravenous fluid administration in a feline patient, the veterinary doctor first assesses hydration status by physical exam, as stated earlier. The skin on the neck is gently pinched to assess whether the feline patient is less than 5% dehydrated. If the skin takes longer to return to its original state, then the patient is 5% dehydrated. This parameter is called checking skin turgor (Naden, 2020). At 5% dehydration, the patient will likely have poor appetite and general body weakness.
For 8% dehydration, the capillary refill time (CPT) is assessed. This is done by pressing and releasing the gum on the patient’s upper teeth to observe how long it will take for the pink color to return. If it takes 3 seconds or more, it is a slow CPT, indicating 8% dehydration. Also, the patient may experience excessive panting due to the body’s inability to maintain vital processes.
For 10% to 12% dehydration, the patient will have sunken eyes, dry gums, increased heart rate, cold paws, and altered consciousness (Naden, 2020). For 15% dehydration, the patient will be in shock and may quickly die. Some cats may collapse or have seizures due to low levels of consciousness caused by neurologic dysfunction. Hence, different physical signs are associated with different levels of dehydration.
Purpose of Fluid Therapy Phases
After determining the dehydration percentage, the amount of fluid is calculated and administered in phases, a process called fluid therapy. There are 3 phases, each with a purpose, especially for a female feline patient. These phases include resuscitation, replacement, and maintenance (Pachtinger, 2022).
The purpose of the resuscitation phase is to treat life-threatening conditions such as shock. The second phase, a replacement, aims to replenish the lost water and electrolytes. Lastly, the maintenance phase focuses on preventing further loss of the administered fluids to correct organ dysfunction and restore homeostasis.
Fluid Rates
Formula 1: % dehydration x bodyweight (kgs) = replacement volume required to correct dehydration (MLS).
Converting lbs to kgs: 1lb = 0.4536kgs, hence, 8lbs = 3.6288kgs.
Therefore, the amount is: 10% x 3.6288 = 0.36288 ml/kg.
Convert to mls: = 362.88 mls.
Calculation of the fluid rate for the replacement phase: Since there are no ongoing losses from vomiting or diarrhea, the cat is placed in the maintenance phase. The maintenance fluid rate formula for a cat is as follows
80 * body weight (kg) (3/4).
Therefore: 80 × 3.6288 × 3/4 = 217.728 mls per 24 hours.
Replacement volume = 362.88 ml (deficit) + 217.728 ml (maintenance) = 580.608 ml per 24 hours.
580.608 ml / 24 hours = 24.19 ml/hour.
Monitoring and the Importance of IV Fluid Therapy
Regarding monitoring IV fluid therapy, two methods can be used. These include laboratory tests and physical examinations. During physical examination, the veterinarian checks the cat’s urine production at least twice a day, their respiratory rate, and other physiological parameters such as renal function, pulse rate, mucous membranes, and urine output (Pachtinger, 2022).For laboratory tests, the veterinarian checks for hydration status using acid-base tests, electrolyte levels, and lactate levels.
However, complications can arise during IV fluid therapy, making it essential to monitor the IV catheter site for patency and potential complications. In doing so, the veterinarian should evaluate the physical equipment, such as the IV infusion line, to ensure the type of fluid and volume are accurate.
Also, there should be a flow sheet to document fluid balance every hour and to monitor fluid status regularly. Monitoring the IV catheter site helps prevent complications such as infiltration, infection, phlebitis, and extravasation. Overall, monitoring IV fluid therapy is essential because it identifies negative or positive responses to fluid therapy (Pachtinger, 2022). This way, the necessary changes can be made immediately.
Patient parameters:
- Skin Turgor: Determining the skin’s moisture state by feeling its suppleness.
- Capillary Refill Time (CPT): Calculating how long it takes for the gums’ color to return to assess blood flow and hydration levels.
- Breathing rate: keeping an eye out for any indications of respiratory trouble.
- Pulse Rate: Keeping an eye on heart rate to maintain good circulation.
- Mucous Membranes: Examining the moisture and color for indications of dehydration or problems with the circulatory system.
- Urine Output: To monitor renal function and fluid balance, measure the urine produced at least twice daily.
- Neurological Status: Watching for symptoms such as seizures or altered consciousness, particularly in cases of severe dehydration (up to 15%).
References
Naden, K. (2020). Developments in surgical fluid therapy rates in veterinary medicine. Veterinary Evidence, 5(3).
Pachtinger, G. (2022). Fluid therapy. Feline Emergency and Critical Care Medicine, 75–82.