Preoperative assessment for surgery

Chapter 1

Preoperative assessment for surgery

Pre-operative assessment of the patient provides a solid foundation for a safe and successful surgical procedure. The assessment relies heavily on information obtained from a thorough history and physical examination. It establishes the baseline physiologic data for the individual, facilitates assessment of intercurrent disease and its potential relevance, identifies current medications that may need adjustment in the perioperative period and directs appropriate preoperative testing.

Arrival and history taking

Evaluation of the patient begins at reception. Sick cats often present for lethargy and inappetence regardless of their underlying disease. Cats should be observed in their carriers by staff on arrival to identify injured or dyspneic patients that require immediate stabilization.

History taking

Regardless of the surgical procedure planned, the clinician should familiarize themselves fully with the medical history. The history can be considered in two parts; the general history and the specific history. The general history involves collection of background epidemiological information for the patient (Box 1-1). Signalment should be confirmed. Owners may, unwittingly, provide inaccurate information on their cat’s age, breed or sex. It should be ascertained whether the cat was acquired as a kitten or as an adult of unknown background. A reasonable estimate of age can be made in cats that are still growing (up to 18–24 months) and in geriatric cats if there is iris discoloration or age-associated disease, e.g., most cats with hyperthyroidism are over 10 years old. Information regarding the cats’ living circumstances is important. Owners of cats living in apartments can usually provide detailed information on toileting, appetite and activity levels that owners of cats that roam will be unable to provide. Owners should be questioned about current medications with the drug, dose, frequency and time of last dosing being recorded. In presurgical patients, special attention should be given to medications that may affect coagulation (e.g., heparins, warfarin, aspirin, and clopidogrel) and wound healing (e.g., prednisolone).

The specific history relates to the presenting complaint (Box 1-2). This establishes what abnormalities the owner has noticed, their duration and the pattern of disease. It is the responsibility of the clinician to find a way of communicating with each owner that best facilitates information flow. Although the problem might not be exactly what the owner perceives it to be, if a problem is reported, there almost certainly is one.

Physical examination

A complete preoperative physical examination is essential to identify factors that may affect surgical outcome. Most cats will allow a thorough examination and respond best to minimal restraint. Special care should be taken with cats that are particularly timid or aggressive. Maintaining a quiet environment and avoiding sudden movement is helpful. Doors and windows should be closed. Further information on providing an appropriate environment for examining cats and the most cat friendly consulting room is provided in Chapter 9.

Handling and acclimatization

The demeanor of the cat and its resting respiratory rate and effort should be observed while it is in its carrier. If the cat appears relaxed, it should be stroked and talked to before lifting it onto the floor or table. If the cat appears aggressive (e.g., ears back and flattened) it is prudent to remove the cat from the top of its carrier swiftly by scruffing the back of the neck with one hand and supporting the cat’s body under its chest with the other hand (Fig. 1-1). Some cats feel threatened when approached to be removed from their cage. Hesitating to remove these cats can precipitate aggressive swiping or biting. A non-aggressive cat can be removed from its carry cage at the start of the consultation and given time to acclimatize while the history is taken. The cat can sit on the consulting table while being gently held or stroked by the owner, or if the cat is not injured or dyspneic, it can explore the room. This can reduce anxiety in an unfamiliar environment before the physical examination begins and permits observation of the cat’s mentation and gait. The ‘window of opportunity’ for examination of the cat can be small and the examination should proceed from least invasive to most invasive procedures, with abdominal palpation, rectal temperature and manipulation of an area suspected to be painful generally performed last.

Blood pressure measurement

Measurement of systolic blood pressure (SBP) is indicated in any cat with evidence of target organ damage, including cats with chronic kidney disease (CKD), retinopathy or choriodopathy, intracranial signs, cardiovascular signs (murmur, gallop, arrhythmia) or epistaxis. SBP pressure should also be measured in obese cats and where thyroid or adrenal disease is suspected. Given that CKD and hyperthyroidism are the most common causes of hypertension in cats, it is prudent to measure blood pressure routinely in any cat that is 10 years of age or older.1 Measurement of SBP should be carried out at the beginning of the physical examination, after acclimatization. This avoids artefactual, anxiety-induced increases or decreases in blood pressure, known as the ‘white-coat’ effect (Fig. 1-2, Box 1-3). Doppler techniques are preferred over oscillometric techniques for measurement of SBP in conscious cats as they are more accurate and faster to measure.2,3

Box 1-3   Systolic blood pressure measurement using Doppler sphygmomanometry

1. To minimize the ‘white-coat’ effect bring the cat, with the owner, into a quiet consultation room away from extraneous noises such as barking dogs. Allow five to ten minutes for the cat to acclimatize to these conditions.

2. With the cat in sternal recumbency or sitting, use an alcohol soaked swab to wet the hair on the palmar aspect of one forelimb adjacent to the metacarpal pad and just proximal to the first phalanx (Fig. 1.2A). Clipping the hair is NOT necessary in most cats. A hindlimb or the tail can also be used.

3. Measure the circumference of the forelimb mid-way between the carpus and the elbow, where the cuff will be placed. The cuff width should be >30% and closest to 40% of the circumference. An undersized cuff overestimates, and an oversized cuff underestimates blood pressure. Place the cuff.

4. Apply coupling gel to the Doppler probe and place the probe on the area prepared, level with the first phalanx and directly over the median artery to obtain a pulse signal. The cuff should be positioned level with the heart. Inflate the cuff to 20–30 mmHg beyond where the pulse is no longer audible. Slowly deflate the cuff. The point at which the pulse is again first audible is the systolic blood pressure (Figs 1.2B, 1.2C).

5. Leaving 30 to 60 seconds between each reading, take five consecutive readings, discard the first, and then calculate the mean systolic blood pressure. Record the cuff size used.

6. Perform fundoscopy to look for evidence of hypertensive choriodopathy or retinopathy (Fig. 1.2D).

Head-to-tail examination

The physical examination can be completed by starting at the head and working caudally. The cat should first be weighed using accurate scales and its body condition score assessed using established 5-point or 9-point scoring systems (see Chapter 6):




Mouth and hydration status

Examine lips/commissures

Elevate upper lip to assess mucous membrane color, moistness, capillary refill time (CRT) (Fig. 1-5). In comparison to the dog, the normal mucous membrane color for cats is paler. Assess the cat’s hydration status (Table 1-1). Signs of dehydration include dry or tacky mucous membranes, a loss of skin turgor (skin tenting between the shoulder blades), prolonged CRT and enophthalmos. Skin tenting as a measure of hydration can be unreliable in geriatric or emaciated cats and the moistness of mucous membranes is more difficult to assess in cats than in dogs

Assess teeth and gingiva

The mouth should be opened (Fig. 1-6). The fauces, tongue and soft palate can be inspected. Subtle jaundice can sometimes be detected first on the soft palate

The underside of the tongue is examined for masses or string foreign bodies by pressing the thumb of the second hand into the intermandibular space to elevate the tongue


Thyroid gland, larynx trachea, jugular vein

Peripheral lymph nodes


Cardiovascular System

Palpate the cardiac apex beat noting intensity and presence of any thrills

Place the diaphragm of the stethoscope over the sternum with the cat standing or sitting and auscultate the heart in sternal and parasternal locations. In a veterinary hospital environment the normal feline heart rate ranges from 140 to 200 beats per minute

Take the heart rate and palpate the femoral pulses simultaneously, noting the pulse amplitude, pulse symmetry and any pulse deficits. Evaluation of femoral pulses is more difficult in the cat than the dog as they are more easily occluded during firm palpation, but their presence should be ascertained

Listen for murmurs, grade them from I to VI and find the point of maximum intensity (PMI). Murmurs can be induced if the stethoscope is pressed too firmly against the chest

Listen for gallop (extra, abnormal) heart sounds. S4 is the gallop sound most often heard in cats. It arises from atrial contraction against a diastolically compromised ventricle, e.g., in hypertrophic cardiomyopathy. The S3 gallop is rare in cats. It is caused by sudden cessation of rapid ventricular filling with vibration of the walls and muscles

Assess the rhythm of the heart as regular, regular–irregular (e.g., sinus arrhythmia, rare in cats compared with dogs) or irregular–irregular (e.g., atrial fibrillation)

Sep 6, 2016 | Posted by in SUGERY, ORTHOPEDICS & ANESTHESIA | Comments Off on Preoperative assessment for surgery
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