Plus-Hex CLINICAL
Background
The patient was a neutered male domestic shorthair cat , which was 4 years and 8 months old and weighed 3.4 kg . Before presenting to the PCP , the patient had been lethargic , inappetent and straining to pass urine for 24 hours . On physical examination at the PCP , a large , firm bladder was palpated , indicative of UO . Laboratory findings indicated severe hyperkalaemia , azotaemia and hyperphosphataemia .
The PCP attempted to stabilise the patient ' s potassium ( K + ) levels before general anaesthesia , achieving only mild improvement . The patient was anaesthetised , the UO was relieved and an indwelling urinary catheter was placed with a closed collection system attached . The patient was transferred to the OOH service for continued care .
Learning outcomes
1 . Understand the importance of close monitoring of patients with UO post catheterisation , including ensuring that urine flow is occurring .
2 . Understand that monitoring trends in acid – base can determine whether a patient is deteriorating and help ensure that interventions are provided quickly .
3 . Understand that veterinary nurses ( VNs ), as well as veterinary surgeons ( VSs ), are responsible for caring for patients , and know how to raise a concern .
4 . Understand the significance of fluid choice in relation to metabolic acidosis .
Presentation
The patient presented to the OOH service in a stuporous condition . On physical examination , it was found to be bradycardic ( 100 bpm ) with moderate , synchronous peripheral pulses and pale pink mucous membranes ( MMs ), with a capillary refill time of 1.5 seconds .
The patient was pain scored using the Glasgow acute pain scale for cats ( a validated scoring system ) and assigned a score of 13 / 20 ; it exhibited severe pain on abdominal palpation despite having being given a partial µ -agonist opioid . It was also mildly hypothermic ( 37.0 ° C ) and had a respiratory rate ( RR ) of 20 breaths / min , with no abnormalities on auscultation .
A closed urine collection system had been connected to the patient before transfer to the OOH service . This was clamped , preventing the flow of urine . The transfer notes suggested that the system had been placed several hours earlier but there was no evidence of urine in the system . The patient was also transferred on intravenous fluid therapy ( IVFT ) of 0.9 % sodium chloride ( saline ).
Veterinary interventions
An initial blood sample was taken to determine a baseline for blood gas analysis . This indicated a critical metabolic acidosis with a pH of 6.957 . The analysis also revealed a severe electrolyte imbalance , with hyponatraemia , hyperkalaemia and ionised hypocalcaemia . A significant azotaemia was also identified by the analysis . The results are shown in Table 1 .
Table 1 . Patient ' s blood test results and the normal parameter range for cats . |
Parameter |
Patient ' s results |
Normal range for cats |
pH |
6.957 |
7.227 – 7.409 |
|
Bicarbonate ( HCO –
3
)
|
9.0 mmol / l |
18.0 – 23.0 mmol / l |
Base excess ( BE ) |
– 23.0 mmol / l |
– 5.0 – 4.2 mmol / l |
Partial pressure of carbon dioxide ( PCO 2 ) |
40.3 mmHg |
32.7 – 44.7 mmHg |
Sodium ( Na + ) |
142 mmol / l |
147 – 162 mmol / l |
Potassium ( K + ) |
7.8 mmol / l |
2.9 – 4.2 mmol / l |
Ionised calcium ( iCa 2 + ) |
0.76 mmol / l |
1.20 – 1.32 mmol / l |
Chloride ( Cl – ) |
127 mmol / l |
112 – 129 mmol / l |
Anion gap |
15 mmol / l |
10 – 27 mmol / l |
Haematocrit |
29 % |
24 – 40 % |
Glucose |
3.4 mmol / l |
3.3 – 7.2 mmol / l |
Lactate |
1.24 mmol / l |
0.5 – 2.7 mmol / l |
Urea |
> 42.8 mmol / l |
5.4 – 12.1 mmol / l |
Creatinine |
1134 µ mol / l |
88 – 195 µ mol / l |
Volume 39 ( 3 ) • June 2024
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