Quick fluid rate chart: maintenance, shock, drops/min for dogs and cats

A 4kg cat presents with 8% dehydration — how many ml over 12 hours, how many drops per minute? A chart next to your fluid pump answers in 5 seconds.

This article distills the AAHA 2024 Fluid Therapy Guidelines into weight-based lookup tables, with dog vs cat rates separated, plus drops/min for gravity drip.

Sources: AAHA 2024, AAHA/AAFP 2013, Merck Vet Manual.

Decision flow before looking up the table

graph LR
    A[Patient needs fluids] --> B{Shock?}
    B -->|Yes| C[Bolus 15-20 ml/kg dog<br/>5-10 ml/kg cat<br/>→ reassess 15 min]
    B -->|No| D{Dehydrated?}
    D -->|Yes| E[BW × % × 10 = ml deficit<br/>Replace over 12-24h]
    D -->|No| F[Maintenance<br/>Dog 2.5 ml/kg/hr<br/>Cat 1.67 ml/kg/hr]
    C --> G[Stabilized → switch to<br/>dehydration/maintenance]

Weight-based lookup table (2-40 kg)

kg	Dog maint ml/hr	Cat maint ml/hr	5% deficit ml	8% deficit ml	Dog shock bolus	Cat shock bolus
2	5	3.3	100	160	30-40	10-20
4	10	6.7	200	320	60-80	20-40
5	12.5	8.3	250	400	75-100	25-50
10	25	16.7	500	800	150-200	50-100
15	37.5	25	750	1,200	225-300	75-150
20	50	33.3	1,000	1,600	300-400	100-200
30	75	—	1,500	2,400	450-600	—
40	100	—	2,000	3,200	600-800	—

⚠️ Cats are always lower than dogs — smaller blood volume, occult cardiac disease common, overload risk higher.

Drops/min — gravity drip

20 gtt/ml (macrodrip): drops/min = ml/hr ÷ 3 60 gtt/ml (microdrip): drops/min = ml/hr

kg	Dog 20gtt	Cat 20gtt	Dog 60gtt	Cat 60gtt
2	2	1	5	3
5	4	3	13	8
10	8	6	25	17
20	17	11	50	33
30	25	—	75	—

Cats: use a syringe pump or microdrip 60gtt — macrodrip is not precise enough at low rates.

Dehydration correction

Formula: BW (kg) × % dehydration × 10 = ml deficit

Replace over 12-24 hours + add ongoing losses (vomiting, diarrhea, drains).

Shock — bolus + reassess

	Dog	Cat
Bolus	15-20 ml/kg	5-10 ml/kg
Duration	Over 15 min	Over 15 min
Then	Reassess → repeat if needed	Reassess → repeat

Full single shock bolus is no longer recommended (AAHA 2024). Give aliquots → reassess perfusion → continue.

Overhydration signs — stop or reduce rate

Sign	Check
Tachypnea, increased respiratory effort	☐
Pulmonary crackles	☐
Serous nasal discharge	☐
Chemosis	☐
Acute weight gain	☐
Jugular distention	☐

Monitoring targets: urine output 1-2 ml/kg/hr, weight q4-8h, RR q1-2h.

CRI drugs — 4 common infusions

Drug	Dose	Loading	Species
Metoclopramide	1-2 mg/kg/day	Not required	Dog/Cat
Lidocaine	20-50 mcg/kg/min	2 mg/kg IV	🔴 DOG ONLY
Fentanyl	1-5 mcg/kg/hr	1-4 mcg/kg IV	Dog/Cat
Dopamine	5-20 mcg/kg/min	Titrate	Dog/Cat

🔴 Lidocaine CRI in cats = cardiotoxicity — do not use.

4 rules to remember

1. Dog ≠ Cat — maintenance dog 60, cat 40 ml/kg/day; shock dog 15-20, cat 5-10
2. Bolus → reassess → continue — never full shock dose at once
3. Monitor for overload — RR, crackles, nasal discharge, weight
4. Lidocaine CRI = dogs only — cats will develop cardiac toxicity

Practice management software like VetGo can integrate a fluid calculator — enter kg + species → auto-calculate maintenance, deficit, bolus, drops/min.

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Sources: AAHA 2024 Fluid Therapy Guidelines, AAHA/AAFP 2013, Merck Veterinary Manual.