Caring for the critical patient
Basic nursing care
Critical patients should minimally have a full physical exam performed every four hours. In some instances a patient may require a nurse to stay with them continuously and vitals checked every 5-15 minutes. A full physical exam should include monitoring for heart rate, respiratory rate and effort, mucous membrane colour, capillary refill time, rectal temperature, and neurological status.
Critical patients are often at risk for disseminated intravascular coagulopathy (DIC). It is important to look for signs, which include excessive bleeding after venipuncture sticks and/or petechiae on the gums, pinna, or abdomen of the pet. When performing a mucous membrane check it is important to look at the gums for petechiae.
Rapid changes in body weight are usually a result of fluid gains or losses. Critical patients can often experience large fluctuations in weight due to fluid shifting, and/or retention or loss of fluids through vomiting and/or diarrhea. A 0.5 kg weight gain is equivalent to a 0.5 litre fluid gain.
Urine output should be monitored and recorded. Quantifying urine output is key in monitoring fluid therapy and also to look for signs of renal injury in critical patients. Since critical patients may experience multiple organ dysfunctions, kidney failure may occur in these patients. The total volume of fluid administered to the patient should ideally be equal to urine output.
Advanced nursing care
Since critical patients often require frequent blood draws, a central line should be placed. This will allow for faster and pain-free blood collection, and help prevent veins from being overused. A central line may not be possible if the patient is in DIC, experiencing a coagulation disorder, or suffering from head trauma.
An arterial line should be considered in patients experiencing respiratory problems or blood pressure issues. This will allow for measurement of partial pressure of oxygen in arterial blood (PaO2), which is the gold standard when measuring overall oxygenation ability. It also allows for the gold standard of measuring blood pressure through invasive blood pressure monitoring. Arterial lines should always be labelled properly, and drugs and certain types of fluids should never be administered into an artery. Arterial lines should have all lines leading up to them with luer lock adaptors; if a patient disconnects a line leading into an arterial line they can suffer massive blood loss.
Blood pressure can be monitored either directly or indirectly. Direct (invasive) arterial pressure monitoring is the gold standard. It requires the placement of an arterial catheter, which can also be used to obtain arterial blood gas samples and to monitor PaO2. An electronic transducer is placed at the end of the arterial catheter and monitored continuously. If an electronic transducer is not available the blood pressure can be measured using a central venous pressure manometer. Indirect methods include oscillometric devices or doppler ultrasound flow detectors. Indirect readings are less accurate, but require less skill and are noninvasive.
Central venous pressure (CVP) is generally used when a patient is prone to changes in blood pressure or when aggressive fluid therapy is being utilized. CVP is considered a measurement of cardiac pumping ability, circulating blood flow, vascular tone, and intrathoracic pressures. Depending on the literature, normal CVP values may vary, but most will agree it is somewhere between 1-10 cm H2O. Certain multi-parameter machines have the ability to perform digital CVP readings, which eliminates subjectivity. The most accurate machines pass a transducer into the central line and allow for electronic CVP readings to be taken directly from the heart.
Lactate accumulates in the tissues and blood as a result of inadequate oxygen availability, which is generally caused by tissue hypoperfusion. In some cases increases in lactate may be the only indication that hypoperfusion exists. Increases in lactate are commonly seen in critical patients that are not perfusing well; a value of less than 2.5 mmol/L is considered normal.
Urinary catheters should be placed in any recumbent critical patient, ensuring that bags and lines do not touch or drag on the ground. Anyone handling lines should wear gloves and, more importantly, wash their hands immediately before handling. The use of prophylactic antibiotics is not generally recommended in patients with urinary tract infections.
Critical patients may have chest tubes, drains, feeding tubes, and/or nasal lines. Gloves should be worn when handling critical patients with drains and chest tubes since both drains and chest tubes require the removal of air or fluid from the patient, which may be contaminated with bacteria. It is good practice to protect yourself as well as the patient. Patients with chest tubes should be monitored closely as disconnection from a suction machine may result in a fatal open pneumothorax. Chest tubes should always have a three-way stopcock in the off position as added security
Nutritional support
Nutritional support must be considered in critical patients that are hospitalized for more than 48 hours. Disease and injuries cause an increase in resting energy expenditure and increased protein consumption. In both human and veterinary patients, a better outcome is seen in those that receive early nutritional support.
Pain management
Most critical patients are in some level of pain. This is particularly true for post-operative patients. As the patient’s nurse it is imperative that you watch for signs of pain. In dogs this may include vocalizing, shaking, aggression, and panting. Cats more commonly will become aggressive or hide. Opioids are the choice of drugs for critical patients because they offer excellent analgesia with limited effects on the hemodynamic system. Multimodal and continuous rate infusion analgesia should be considered in these patients.
Ventilator/down patient
In some cases, critical patients may be put on a ventilator if they are experiencing severe respiratory distress. As a veterinary nurse you will be responsible for the maintenance of the ventilator machine. Since each machine is a little different, reading the manual is strongly recommended. Patients on ventilation often require a dedicated around-the-clock nurse.
It is important that the ventilated air entering the patient be humidified. Oral mucous membranes and eyes should be moistened and lubricated to avoid drying out. The mouth itself should be cleaned and rinsed every four hours.
The endotracheal or tracheostomy tube should be suctioned every four hours and endotracheal tubes should be replaced every 24 hours. In addition, the cuff on the tubes should be deflated, repositioned, and reinflated every four to six hours. Tracheostomy tube care should be focused on preventing secretion build-up, providing aseptic wound care, and humidifying inspired air.
Since critical patients are recumbent, passive range of motion must be performed every four to six hours and patients should be repositioned at that time as well. A urinary catheter should be placed as well, to keep them as clean and dry as possible. Adequate soft bedding should be used and bedding should be cleaned and replaced daily.
Amy is currently employed at BluePearl Massachusetts in Waltham, MA as the Emergency Head Technician. In 2003 she became boarded as a Veterinary Technician Specialist in Emergency and Critical Care. She currently sits on the Academy of Veterinary Emergency & Critical Care Technicians board as the President-Elect. Amy is well published in over 15 subjects, is an international speaker, has received numerous awards and highly involved in her community. Most recently Amy was awarded the Speaker of the Year at the 2014 NAVC Conference. She lives in Massachusetts with her husband and wonderful furry kids.
This article is based on Ms. Breton’s presentation at the Veterinary Emergency and Critical Care Society Conference in Indianapolis, IN.CVT
