Metabolic Response to Trauma

Dr Manjula Peiris MBBS MD MRCS

Lecturer, Department of Surgery

23/11/2012

Systemic Effects of Surgery

• Activation of the sympathetic nervous system• Endocrine ‘stress response’– Pituitary hormone secretion– Insulin resistance

• Immunological and haematological changes– Cytokine production– Acute phase reaction– Neutrophil leucocytoisis– Lymphocyte proliferation

Fluid, Electrolyte, Acid base..

• Cuthbertson 1932– ‘Ebb’– ‘Flow’

• Sodium retention• Chloride, Calcium, magnesium• Potassium

• Acidosis

Endocrine ResponsePituitary

ACTH, GH increase, TSH and FSH/LH variable responseADH (Vasopressin) increases

Adrenal cortexcortisol, aldosterone increase

PancreasInsulin decreasesGlucagon increases

Thyroxine, T3decrease

HORMONAL ‘AXIS’

• Sympatho adrenal

• Hypothalamo pititary adrenal

• Corticotrophin

• Insulin, glucagon

INDIVIDUAL HORMONES(HOME WORK)

• Adrenaline, noradrenaline, dopamine, dobutamine, vasopressin, somatostatin, prolactin, Growth hormone, TSH, GnRH, FSH, LH, Thyroxin, triiodothyronine, ACTH, renin, angiotensin1, angiotensin2, aldosterone, cortisol, endorphin, insulin, glucagon…

• Trigger Factors for release• Inhibitory factors• Effects on individual receptors..– Alpha 1,2 beta 1, 2, 3 etc…

HOW IS IT ALL TIED UP?

?

Effects of trauma

• Bleeding• Pain• Loss of function• ….

Fright Fight or Fight

• ‘Superman’– Eyes – Pupils dilate to see better– Brain perfuses– Muscles perfuse – to run/fight

– No need to eat– No need to pee– No need to poo

ADRENALINE

Somehow escape..

• Maintain Blood pressure– Perfuse the brain– Perfuse the heart

• No need to run/fight/pee/poo• No need to perfuse the muscle or splanchnics!

NORADRENALINE

How to save water?

• ADH/Vasopressin– ‘Volume’ and osmoreceptors– Acts on the distal convoluted tubule and collecting

duct– Antidiuretic effect AVPR2• Also releases clotting factors from the liver

– Pressor effect AVPR1

Renin

• Possibly– Hypovolaemia?

– Hyponatraemia?

– Pain/stress?

Renin is secreted…

• A decrease in arterial blood pressure (that could be related to a decrease in blood volume) as detected by baroreceptors (pressure-sensitive cells). This is the most direct causal link between blood pressure and renin secretion (the other two methods operate via longer pathways).

• A decrease in sodium chloride levels in the ultra-filtrate of the nephron. This flow is measured by the macula densa of the juxtaglomerular apparatus.

• Sympathetic nervous system activity, which also controls blood pressure, acting through the beta1 adrenergic receptors.

Angiotensin

Aldosterone

• Angiotensin III• Angiotensin II• ACTH• Potassium• Acidosis• Atrial stretch receptors

Cortisol• Stress, pain, hypovolaemia

• Acts on the muscle– Produces amino acids

• Acts on the liver– Produces glucose • (the brain does not need insulin to take up glucose!)

• Acts on the adipose tissue– Produces ketone bodies that can fuel the heart

Observe:

• Urine volume becomes less – ebb• Sodium less and potassium and acid increased• Nitrogen content increases

– Muscle breakdown– Amino acids converted to fuels– Nitrogen excreted

Ambiguous roles

• Growth Hormone– Inhibits protein breakdown– Promotes lipolysis and gluconeogenesis– ‘saves the glucose’ for the brain

• Glucagon– Increases gluconeogenesis– Increases glycogenolysis

THYROXIN

• TSH, T4, T3 decrease following surgery• Thyroxine increases oxygen consumption by

cells (except brain, spleen and anterior pituitary)

• Is it an oxygen sparing effect?

Recovery (Flow phase)

• Reversal of everything..• Insulin starts replenishing ‘stocks’• Dual role of GH• ‘Anabolic’ steroids

Adverse effects

• Prolonged catabolism– Akin to starvation

• Patient remains ill• Wasting• Immunocompromise• Poor healing• Essential amino acid and fatty acid deficiencies

DO WE NEED IT?

• Cannot be abolished• Can be attenuated– Opioids, benzodiazepines (?)– Minimal access– Regional anaesthesia– Fast track recovery– Caloric supplementation (?)– (?)….

Take Home

• Try and form associations between the actions of hormones

• Learn to recognize and look for reasons where there is a prolonged stress response

• Explore the avenues of expediting recovery…