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Example Fluid Prescription Calculation
Оглавление25 kg mixed breed dog (lean body condition)
Estimated to be 8% dehydrated based on physical exam findings (tacky mucous membranes, prolonged skin tent, slightly sunken globes, hyperviscous saliva in the corner of the mouth).
No conditions that would make the patient fluid intolerant; plan to correct over 24 hours.
The dog is losing approximately 60 ml in vomit every hour, no excessive gastrointestinal or urinary losses.
Deficit = 0.08 × 25
Deficit = 2000 ml
Rate of deficit correction = 2000/24 = 83 ml/hour
Fluid prescription (per hour) = 83 ml (deficit) + 60 ml (losses) + 50 ml (maintenance)
Fluid prescription = 193 ml/hour
Electrolyte monitoring should be performed routinely (Table 1.2) in patients with dehydration and shock. This is particularly true in anorexic patients or those with renal dysfunction, which may require supplementation with potassium and/or phosphorus. Additionally, as many fluids used in veterinary medicine are designed as “replacement” and not “maintenance” fluids, sodium values may increase in patients receiving prolonged intravenous fluid therapy, particularly in patients with continued free water loss, such as renal, gastrointestinal, skin, and respiratory loss. Fluids with lower sodium concentrations such as Normosol‐M, 0.45% NaCl, and dextrose 5% in water (D5W) may be necessary to prevent or manage hypernatremia associated with prolonged fluid therapy and/or concurrent hypotonic fluid losses.
Table 1.2 Monitoring parameter guidelines and frequencies for dehydrated patients and those in hypovolemic, distributive, and hypoxemic shock.
| Physical assessmenta | Blood pressure | SpO2 | Urine output/specific gravity | PCV/TS/BG/Azo Stick® | VBG/ABG/electrolytes | |
|---|---|---|---|---|---|---|
| Dehydrationb | 8–12 hours | 8–12 hours | 12–24 hours | 8–12 hours | 12–24 hours | 12–24 hours |
| Hypovolemic shock | 1–2 hours initially, then 4–6 hours once stabilized | 1–2 hours initially, then 4–6 hours | 4–6 hours | 4–6 hours | 4–6 hours initially, then 6–8 hours | 4–6 hours initially, then 6–8 hours |
| Distributive shock | 1–2 hours initially, then 4–6 hours once stabilized | 1–2 hours initially, then 4–6 hours | 4–6 hours | 4–6 hours | 6–8 hours | 6–8 hours |
| Hypoxemic shock | 1–2 hours initially, then 4–6 hours once stabilizedc | 2–6 hoursc | 1–4 hoursc | 4–6 hoursc | 12–24 hours and after pRBC transfusionc | 12–24 hoursc |
a Physical assessment parameters include hydration evaluation, mucous membranes, capillary refill time, respiratory rate and effort, cardiac and thoracic auscultation, pulse quality, and temperature.
b Dehydrated patients should also be weighed every 8–12 hours.
c Frequency of diagnostics will depend on patient stability and amount of stress caused to the patient with handling, evaluation, and blood sampling.
ABG, arterial blood gases; BG, blood glucose; PCV, packed cell volume; SpO2, peripheral capillary oxygen saturation; TS, total solids; VBG, venous blood gases.
Table 1.3 Analgesics, sedatives, and anxiolytics used in small animal medicine.
Source: Adapted from Quant and Lee JA [105] and Perkowski [106].
| Generic drug | Brand (manufacturer) | Dose | Comment |
|---|---|---|---|
| Opioids: | |||
| Buprenorphine | Buprenex® (Reckitt & Colman) | 5–20 μg/kg IM, IV q 6–8 hours Cats: 10–20 μg/kg PO q 6–8 hours | μ‐partial agonist Excellent oral absorption (cats) Difficult to reverse |
| Butorphanol | Torbutrol®, Torbugesic‐SA® (Zoetis) | 0.1–0.4 mg/kg IM, IV q 1‐4hours Partial μ reversal: 0.05–0.1 mg/kg IV CRI loading dose: 0.1 mg/kg IV CRI: 0.1–0.4 mg/kg/hours IV | κ‐agonists μ‐antagonist Variable analgesia Sedative and anti‐tussive |
| Fentanyl | Abstral® (Abbott Laboratories) | Dog loading dose: 1–2 μg/kg Dog CRI: 2–5 μg/kg/hours Cat loading dose: 1 μg/kg/hours Cat CRI: 1–4 μg/kg/hours | Can cause SIADH with prolonged use |
| Fentanyl transdermal patch | Duragesic® (Janssen Pharmaceuticals) | Cat or dog < 5 kg: 25 μg patch Dog 5–10 kg: 25 μg patch Dog 10–20 kg: 50 μg patch Dog 20–30 kg: 75 μg patch Dog >30 kg: 100 μg patch | Topical heat can increase absorption Caution for abuse potential/ingestion by children |
| Hydromorphone HCl | Dog: 0.05–0.2 mg/kg IM, SQ, 0.05–0.1 mg/kg IV every q 4–6 hours Cat: 0.05–0.1 mg/kg IM, S, 0.03–0.05 mg/kg IV every q 3–4 hours | IV administration can cause vomiting | |
| Methadone HCl | Dog: 0.1–0.4 mg/kg IV every q 4–6 hours Dog: 0.2–2 mg/kg SQ, IM every q 4–6 hours Cat: 0.05–0.2 mg/kg IV every q 4–6 hours Cat: 0.1–1 mg/kg SQ, IM every q 4–6 hours | Tends to cause less sedation and vomiting than morphine | |
| Morphine (preservative free) | Dog: 0.25–1 mg/kg IM, SQ every q 4–6 hours Cat: 0.05–0.5 mg/kg IM, SQ every q 4–6 hours Loading dose: 0.15–0.5 mg/kg IV CRI: 0.1–1 mg/kg/hour | IV administration must be done slowly to avoid histamine release, IV administration can cause vomiting | |
| Morphine sulfate (with preservative) | Dog: 0.5–2 mg/kg IM, SQ every q 4 hours Cat: 0.05–0.4 mg/kg IM, SQ every q 3–6 hours | ||
| Naloxone | Narcan® (DuPont Pharma) | Opioid reversal: 0.002–0.2 mg/kg IM, IV, SQ | May need to be repeated after 20–30 minutes as required |
| Oxymorphone | Numorphan® (Endo Labs) | Dog: 0.02–0.2 mg/kg IV every q 1–4 hours Dog: 0.05–0.2 mg/kg IM, SQ every q 2–6 hours Cat: 0.01–0.05 mg/kg IV every q 2–4 hours | |
| Lidocaine: | |||
| Lidocaine 1% preservative free | Dog loading dose: 1–2 mg/kg IV Dog CRI: 20–80 μg/kg/minute | Controversial for IV use in cats | |
| NMDA antagonists: | |||
| Ketamine | KetaFlo® (Abbott Laboratories) Ketaset® (Fort Dodge Animal Health) Vetamine® (Schering‐Plough) | Sedation: 2–10 mg/kg IV, IM Loading dose: 0.5–1 mg/kg IV CRI: 0.1–0.6 mg/kg/hour | Caution with hypertension, heart disease Controversial in head trauma, increased ICP/IOP, renal disease (cats) |
| Alpha‐2 Adrenergics | |||
| Dexmedetomidine HCl | Dexdomitor® (Pfizer) | Sedation: 1–10 μg/kg IV, IM Loading dose: 0.5–1 μg/kg IV CRI: 0.25–3 μg/kg/hour | Caution with cardiovascular disease or instability |
| Atipamezole | Antisedan® (Pfizer) | Alpha‐2 Adrenergic reversal: 0.05–0.2 mg/kg IV, IM | Same volume as dexmedetomidine given IM |
| Benzodiazepines: | |||
| Midazolam | 0.1–0.5 mg/kg IM, IV CRI: 0.1–0.5 mg/kg/hour | ||
| Diazepam | 0.1–0.5 mg/kg IV CRI: 0.1–0.5 mg/kg/hour | Propylene glycol vehicle; avoid prolonged IV use or IM injection | |
| Flumazenil | Benzodiazepine reversal: 0.01–0.02 mg/kg IV | May need to be repeated after 20–30 minutes as required | |
| Phenothiazines: | |||
| Acepromazine | Aceproject® (Fort Dodge Animal Health) | 0.005–0.01 mg/kg IV every 4–6 hours 0.01–0.05 mg/kg IM, SQ every 4–6 hours | Caution in hypovolemia Do not exceed 2 mg/kg in large dogs |
| Non‐steroidal anti‐inflammatory drugs: | |||
| Carprofen | Rimadyl® (Pfizer) | Dogs: 2–4 mg/kg IV, SQ (single dose) Dogs: 2 mg/kg PO 12 or 4 mg/kg PO once daily24 hours | IV or SQ should only be given when normothermic/normotensive |
| Deracoxib | Deramaxx® (Novartis) | Dogs: 1–2 mg/kg/day | |
| Meloxicam | Metacam® (Boerhringer Ingelheim) OroCAM® (Abbott Laboratories) | Dogs: 0.1–0.2 mg/kg IV, SQ (single dose) Dogs: 0.1 mg/kg PO or transmucosal once daily | Black box warning for cats Transmucosal oral spray for dogs > 2.5 kg |
| Piroxicam | Feldene® (Pfizer) | Dogs: 0.3 mg/kg PO once daily | |
| Robenacoxib | Onsior® (Novartis) | Dogs: 2 mg/kg SQ 30 minutes before start of surgery then every q 24 hours for a maximum of 3 days Dogs: 1–2 mg/kg PO once daily Cats: 2 mg/kg SQ 30 minutes before start of surgery then every q 24 hours for a maximum of 3 days Cats: 1 mg/kg PO once daily for a maximum of 3 days | Do not divide/break/crush feline tablets, therefore, dose range in cats of 1–2.4 mg/kg Do not use in dogs or cats less 4 months of age Do not use tablets in cats < 2.5 kg |
CRI, constant rate infusion; ICP, intracranial pressure; IM, intramuscularly; IOP, intraocular pressure; IV, intravenously; NMDA, N‐methyl‐d‐aspartate; PO, per os (orally); SIADH, syndrome of inappropriate anti‐diuretic hormone.
Fluid therapy in the burned veterinary patient requires special consideration, especially with respect to percentage of total body surface area affected. For information on fluid therapy for the burned patient, see Chapter 53.
Regardless of fluid type and rate used to treat shock and or dehydration, frequent patient reassessment is critical. General recommendations for patient re‐evaluation are listed in Table 1.2.
