RER, resting energy expenditure.
Many critical patients have an altered fluid balance. Depending on the individual case, they often receive large volumes of crystalloids, colloids or blood products. It is vital to measure fluids in and out over a period of time and the veterinary nurse should understand the period of time that these products are likely to be present in the patient’s circulation before moving into the interstitium, or before being broken down in the kidneys and passed out in the urine (see Chapter 2 for more details). Fluid ‘ins’ can include water consumption, nutrition and parenteral fluids; fluid ‘outs’ include urine, faeces, vomit, wound drainage, third space losses. Patients should be weighed twice daily as an assessment of fluid loss and gain, and this information can be used in combination with clinical examination and PCV/TP to estimate fluid balance. See Chapter 2 for more information on fluid therapy and fluid balance.
The nutritional status of the patient is a major consideration that should be addressed on a daily basis. Body weight, body condition score and disease processes should all be taken into consideration when assessing the patient’s nutritional requirements. The patient’s daily RER should be calculated and an estimate made as to whether the patient is voluntarily consuming the requirement. If not, then techniques to achieve this should be considered, including appetite stimulants or assisted feeding techniques such as feeding tube placement.
Ensuring adequate nutrition is vital in the critical patient and should be initiated as early as possible in the hospitalised patient. See Chapter 16 for more details.
Care of Indwelling Catheters and Tubes
Commonly, the critical patient will have numerous indwelling tubes and drains, and it is vital that these devices are correctly managed and cared for. Patients hospitalised within the ICU are at highest risk of developing hospital-acquired infections, because of the presence of indwelling devices and decreased immune systems so correct protocols for their care are vital. When handing devices, asepsis should always be maintained, patency must be maintained to ensure catheters, drains, feeding tubes, etc. can function correctly, and complications must be kept to a minimum. Additionally, bandages should be changed twice daily as a minimum and the insertion or stoma sites checked for signs of redness, swelling, infection, etc. It is also advisable to label these bandages so incorrect medications are not administered into tubes or catheters. Aseptic technique should be strictly adhered to whenever dealing with indwelling devices. Ideally, sterile gloves, but certainly examination gloves should be worn throughout catheter and drain care procedures.
Intravenous catheters (both peripheral and central) should be placed aseptically, flushed every 4–6 hours, the dressing removed, the insertion site checked for extravasation of fluid and infection, and dressing replaced once or twice daily. Once the catheter is no longer required it should be removed. If venous access is required at a later time, another catheter can be placed. The date of catheter insertion should be noted on the patient’s records and/or hospital sheet, and administration sets should be replaced every time a new catheter is placed. Connectors and injection ports should be swabbed with alcohol and allowed to dry before being used. Infections can be minimised by keeping intravenous fluid lines as closed systems and keeping disconnections to a minimum. See Chapter 2 for more information on vascular access including catheter care. See website documents: Hospitalisation sheets.
Chest drains should be aspirated every 2–4 hours. Aseptic technique should be used whenever tubes are handled, particularly for aspiration, and when handling connection points, e.g. three-way taps. If a dressing was applied it should be removed ideally twice, but certainly once daily, and stoma sites inspected for signs of infection. The area around the stoma should be gently cleaned using a dilute chlorhexidine or povidone–iodine solution. Previously it was recommended that antibiotic cream should be used around the stoma site, but this is no longer recommended because of the incidence of multi-drug resistance becoming increasingly common, including resistance to topically applied antibiotics, e.g. mupirocin. Instead, topical anti-microbial dressings, e.g. honey, silver, polyhexamethylene biguanide (PHMB) are recommended.
Twenty-four hour care is essential in patients with tracheostomy tubes in place as potentially fatal occlusion of the tube by exudate, mucus, bedding or skin folds may occur, as well as tube dislodgement (see Figure 19.1). If present, the inner cannula of the tube should be removed for cleaning whenever an increased noise or effort in respiration is detected, or initially every 2 hours post-placement. The cannula should be cleaned thoroughly using warm water, allowed to air dry and then replaced. For tracheostomy tubes without an inner cannula, the entire tube should be removed for cleaning. Ideally, a spare sterile tracheostomy tube should be available for immediate replacement into the trachea following the removal of the dirty tube. The stay sutures above and below the tracheal incision should be used to gently bring the trachea to the level of the skin and to open the trachea.
If the inner cannula or lumen of the tracheostomy tube is repeatedly full of exudate or mucous, then either nebulised air should be used for periods for the animal to inhale (see Figure 19.2), or 0.1 mg/kg sterile saline should be instilled into the tube every 2 hours (the instillation of the tube may initiate transient coughing).
Suction of the tracheostomy tube should be performed only as required. It is required more frequently in smaller dogs and cats (see Figure 19.3). The patient should be pre-oxygenated for 30–60 seconds before suction is performed. A sterile suction catheter should be introduced aseptically into the tracheostomy tube and suction applied for no more than 10 seconds, whilst gently rotating the suction tube. The suction catheter should remain within the tube during suctioning and only inserted into the delicate trachea if absolutely necessary to clear an obstruction distal to the tracheostomy tube.
The tracheostomy stoma should be inspected at least once, preferably twice, daily. The area should be gently cleaned using sterile saline-soaked swabs. If the above measures do not relieve breathing difficulties then the entire tube should be changed. It is important that a veterinary surgeon is on-hand and the ability to perform endotracheal intubation and oxygen administration are readily available. The patient should be pre-oxygenated and the trachea stabilised using the stay sutures around the tracheal rings, above and below the tracheostomy site. The existing tube should be removed and a new tube rapidly inserted.
For naso-oesophageal and nasogastric tubes, the patient’s nares should be cleaned using damp cotton wool twice daily. Oesophagostomy and gastrotomy tubes should be inspected and have the stoma site cleaned using chlorhexidine or povidone–iodine solution at least once, preferably twice daily. As with intravenous catheters, antibiotic cream should no longer be applied around the stoma site and a topical antimicrobial dressing applied instead (see Figure 19.4). All tubes should be flushed before feeding using 5–10 ml lukewarm water. Gastrostomy tubes should have the contents of the stomach aspirated before feeding. If there is a delay in gastric emptying, and there is more than half the previous feed in the stomach, then the veterinary surgeon should be informed and the meal reduced. In this situation motility modifiers may be considered. The tube should be flushed again post-feeding using 5–10 ml lukewarm water, to maintain a column of water within the tube between feeds to minimise blockages. If tubes do become blocked they may be unblocked by using carbonated drinks, pineapple or cranberry juice to clear the blockage.