ISSN 2398-2942      

Anesthesia: in obese patients

icanis

General

  • An ideal body condition score (BCS) Body condition scores of 2.5/5 or 4/9 equals a body fat percentage (BF%) of 15-20%.
  • A patient is obese if:
    • Body weight exceeds >15% of ideal body weight.
    • BCS is 5/5 or 8-9/9.
    • BF% >35%.
  • Obesity Obesity increases morbidity and mortality in small animals, eg cats weighing >6 kg are nearly 3 times more likely to die compared to cats weighing 2-6 kg.
  • Epidemiologic studies have not shown obesity to be a risk factor for cardiopulmonary disorders in dogs and cats, but:
    • Increased body mass results in increased metabolic oxygen requirements and consequent increased circulating blood volume, increased heart rate and cardiac output.
    • Respiratory rates are often increased to compensate for relatively small tidal volumes.
    • It has been demonstrated that excessive body weight has a negative impact on oxygenation in dogs.
  • Co-morbidities may be present:
  • Lower esophageal sphincter tone is reduced, with consequent increased risk of reflux and regurgitation Regurgitation.
  • Obese patients have an increased risk of surgical site infections.
  • Obese patients present many challenges:
    • Heart and lung auscultation may be difficult.
    • Intramuscular injections may require longer needles than usual and deposition of drugs into fat instead of muscle may result in poor or delayed sedation with pre-anesthetic medication.
    • Peripheral veins may be difficult to localize for catheterization.
    • They may not cope very well with dorsal recumbency because of reduced total volume and functional residual capacity of their lungs and the additional weight compressing the diaphragm:
    • Increased airway resistance with airway hyperreactivity.
    • Anatomical landmarks may be obscured and local anesthetic techniques may therefore be more challenging.
  • There is little evidence-based information on anesthesia of obese small animal patients.

Pharmacology

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Drug dosing

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Anesthesia

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Chandler M J (2016) Impact of Obesity on Cardiopulmonary Disease. Vet Clin North Am Small Anim Pract 46 (5), 817-830 PubMed.
  • Love L & Cline M G (2015) Perioperative physiology and pharmacology in the obese small animal patient. Vet Anaesth Analg 42 (2), 119-132 PubMed.
  • Brooks D, Churchill J, Fein K et al (2014) 2014 AAHA Weight Management Guidelines for Dogs and Cats. JAAHA 50 (1), 1-11 PubMed.
  • Boveri S, Brearley J C, Dugdale A H (2013) The effect of body condition on propofol requirement in dogs. Vet Anaesth Analg 40 (5), 449-454 PubMed.
  • Mosing M, German A J, Holden S L et al (2013) Oxygenation and ventilation characteristics in obese sedated dogs before and after weight loss: a clinical trial. Vet J 198 (2), 367-371 PubMed.
  • Pelosi A, Rosenstein D, Abood S K et al (2012) Cardiac effect of short-term experimental weight gain and loss in dogs. Vet Rec 172 (6), 153 PubMed.
  • Ingrande J & Lemmens H J (2010) Dose adjustment of anaesthetics in the morbidly obese. Brit J Anaesth 105 (S1), i16–i23 PubMed.
  • Araghi A, Bander J J & Guzman J A (2006) Arterial blood pressure monitoring in overweight critically ill patients: invasive or noninvasive? Critical Care 10 (2), R64 PubMed.

Other sources of information

Can’t find what you’re looking for?

We have an ever growing content library on Vetlexicon so if you ever find we haven't covered something that you need please fill in the form below and let us know!

 
 
 
 

To show you are not a Bot please can you enter the number showing adjacent to this field

 Security code