Shock rate fluids
It is important that patients that are in a state of shock are treated with fluid given at a shock rate as quickly as possible. This will help to support the cardiovascular system so it can deliver oxygen to the vital organs.
When shock is not adequately treated, there can be severe and significant effects on vital organs including the brain, kidneys and heart. There are four main types of shock that a patient can develop: hypovolaemic, distributive, cardiogenic and obstructive shock [ 7 ].
IVFT can be used to support patients in a state of shock, especially those in hypovolaemic shock. To help increase and support the circulating blood volume, an isotonic crystalloid such as Harmann ' s solution is often used, although, depending on the case, other products may be preferred. Patients given fluid therapy intravenously should be monitored carefully for signs of over-infusion [ 7 ].
Shock bolus rates can vary depending on the severity of shock, but in many cases the bolus can be given over a period of 30 minutes( Table 3).
Table 3. Shock fluid rates for the cat and dog. Adapted from Boag and Marshall( 2020) [ 7 ].
Species
Moderate to severe shock
Severe shock
Cat 5 – 10 ml / kg 40 – 60 ml / kg
Dog 10 – 40 ml / kg 60 – 90 ml / kg
Fluid therapy administration routes
Fluids can be administered to a patient by a variety of routes, depending on how quickly they are required to be absorbed into the circulatory system. A full assessment of the patient should be carried out before deciding which route of administration to use [ 6 ].
Intravenous
The majority of patients that have been prescribed fluid therapy will receive it via the intravenous( IV) route. Fluid therapy will be delivered through an IV catheter, which is usually placed into the cephalic vein in the forelimb.
The IV route allows a large volume of fluid to be given at a chosen rate, which can be controlled through the use of an infusion pump. IVFT can be tailored to each individual patient, with the fluid type and rate of administration being able to be changed as required. IV fluids are often given through a T-connector, which is attached to the IV catheter. The site should be routinely monitored to ensure that the IV catheter is still patent. A T-connector provides a convenient access point for managing repeated / ongoing fluid and medication needs of patients, while preserving the integrity of the primary IV catheter placement and the comfort of the patient.
Bolus fluid rates can also be given, where a larger volume of fluid is delivered via the IV route over a shorter amount of time. This can help in emergency situations, such as severe dehydration and shock.
Subcutaneous
It is important to communicate with both the VS and the wider nursing team when administering shock-rate fluids, so that patients can be monitored and the rate changed as required.
Shock bolus volume can be calculated as follows:
Weight( kg) × shock rate( ml / kg) = shock bolus volume( ml)
Box 4 shows an example of a 8 kg Jack Russell terrier that presents with shock. The VS instructs that a 40 ml / kg bolus be given over 30 minutes.
Box 4. Example shock-rate bolus volume calculation for a dog weighing 8 kg.
8 kg × 40 ml / kg = 320 ml bolus required over 30 minutes
The subcutaneous( SC) route can be used to administer fluids to patients in non-critical scenarios. The advantages of SC administration include it being low cost to the client, relatively well accepted by patients and reducing the need for hospitalisation [ 6 ].
There are some limitations associated with SC fluid administration. It is recommended that the volume of fluid administered at each SC site does not exceed 10 ml / kg, making it difficult to use the SC route if an animal requires a large volume of fluid. Multiple sites can be used, but the patient may not tolerate this approach. Also, it is impossible to control the absorption rate of SC fluids, making it difficult to give a controlled dose over a set period of time [ 6 ].
Isotonic fluids, including saline and lactated Ringer ' s solution, are commonly used for SC administration [ 6 ]. There are two main ways to administer fluids via the SC route. The first is by using a needle and syringe, similar to an SC injection. While this is a quick and easy way to administer SC fluids, they are often delivered under high pressure, making it less tolerable for the patient.
56 Veterinary Nursing Journal