Page 51 - Basic Monitoring in Canine and Feline Emergency Patients

days, and, if the patient’s hypertension is not satis- Case study 2: Hypotension
factorily controlled, the dose of medication may be
VetBooks.ir increased or a third medication may be considered. A 5-year old spayed female Golden Retriever is pre-
sented for evaluation after three days of vomiting
If the starting regimen is an ACEi combined with a
CCB, then an ARB may be a reasonable third
argy over the last 12 hours. Abnormal vital signs
option. Alternatively, hydralazine (direct vasodila- and anorexia with progressive weakness and leth-
tor) may be a more potent third option at a starting include pyrexia (40.2°C) and tachycardia (180
dose of 0.5 mg/kg twice daily. beats/min). Physical examination abnormalities
In addition to the management of the dog’s include pale pink mucous membranes, delayed capil-
hypertension, further diagnostics are indicated to lary refill time (2 seconds), bilaterally weak but
look for an underlying cause of the hypertension synchronous femoral pulses, and diffuse abdominal
(Table 2.2). Considered diagnostics should include discomfort noted during palpation. Blood pressure
a minimum database (complete blood count, chem- readings are consistent and hypotensive using both
istry with electrolytes, and a urinalysis, potentially the Doppler ultrasonic method (78 mmHg) and
with the urine protein-to-creatinine (UPC) ratio oscillometric machine (systolic pressure 75 mmHg,
also calculated). Imaging is frequently necessary MAP 50 mmHg, diastolic pressure 40 mmHg). The
and thoracic radiographs along with abdominal dog’s blood pressure readings are consistent with
radiographs or abdominal ultrasound are options. moderate hypotension and the physical examination
CNS imaging (either through computed tomogra- findings are consistent with a patient who may be
phy or magnetic resonance imaging) may be indi- hypotensive (evidence of decompensatory shock
cated in patients with evidence of CNS TOD, but with weak pulses, tachycardia, pallor and lethargy).
neither appear indicated as this patient was not Treatment of hypotension typically addresses
noted to have other neurologic deficits. fluid deficits prior to pharmacologic intervention. A
In this dog’s case, significant proteinuria was peripheral intravenous catheter was placed expedi-
documented with a UPC ratio of 20.0 (reference: tiously and blood was collected from the catheter to
<0.5). The albumin was slightly low (2.2 g/dL); perform a complete blood count, chemistry profile,
however, the renal values were normal. Thoracic and possibly a lactate measurement. Once the intra-
radiographs were normal and an abdominal ultra- venous catheter was placed, replacement crystalloid
sound was normal outside of diffusely hyperechoic fluids (Normosol-R) was administered as a bolus.
renal cortices. Additional testing was performed This dog was given a quarter of her 90 mL/kg shock
after proteinuria was documented but a heart- fluid bolus (~22 mL/kg) over 10–15 minutes. Due
worm test, rickettsial polymerase chain reaction to only a partial improvement in the monitored
and antibody titer testing, aerobic urine culture, parameters (heart rate reduced to 160 beats/min
and a low-dose dexamethasone suppression test and Doppler blood pressure increased to only 85
were all negative. The dog was presumed to have mmHg), the same ~22 mL/kg bolus was repeated.
primary glomerular proteinuria and secondary After another only marginal improvement (heart
hypertension. The dog was initially treated with rate reduced to 150 beats/min and Doppler blood
benazepril at a 0.5 mg/kg dose adm inistered twice pressure increased to only 90 mmHg), a 5 mL/kg
daily and amlodipine at a 0.1 mg/kg dose adminis- colloid bolus (e.g. hydroxyethyl starch) was admin-
tered once daily. In addition, the dog was switched istered over 10–15 minutes. A more substantial
to a commercial diet aimed at improved renal improvement was noted after the colloid bolus
health. The systolic blood pressure remained ele- (heart rate reduced to 130 beats/min, capillary refill
vated at 175 mmHg when checked after 7 days of time improved to 1–2 seconds, and Doppler blood
therapy. At that time the amlodipine dose was pressure increased to 110 mmHg).
increased to 0.2 mg/kg dose administered once While performing the necessary fluid boluses, a
daily. The blood pressure had decreased to a pre- rapid abdominal ultrasound scan revealed free
hypertensive level with a systolic pressured meas- fluid. Sampling of the fluid revealed a marked
ured at 150 mmHg after 7 days of the increased inflammatory response with both degenerate and
amlodipine dose. At that point, the UPC ratio had non-degenerate neutrophils. Many of the neutro-
decreased to 11.2. A renal biopsy was recom- phils contained rod bacteria, and the diagnosis of
mended but declined by the owner and therapy septic peritonitis was confirmed in this patient.
continued unchanged. A full abdominal ultrasound was later performed

Blood Pressure Monitoring 43