Perioperative Care

1. Perioperative Care • Dr Robin Correa FRCA • Consultant Anaesthetist • 23 March 2011

2. Perioperative Care Preoperative Care Fluid optimisation and nutrition Assessment Intraoperative Care Antibiotic and thromboprophylaxis Sterilisation, disinfection and antisepsis - Transport, positioning, scrubbing up, instruments, incisions, closures, drains, stomas and sutures Postoperative Care Drain, fluid and acid – base management, pain, surgical complications and critical care

3. Fluid Management • Introduction • Fluid compartments • Stress response and fluid • GIFTASUP recommendations

4. Introduction • Fluid and electrolyte balance consists of : - external balance between the body and its environment - internal balance intravascular, interstitial and intracellular compartments • Twenty four hour requirements in normal adult are 25 – 35 mL/kg or 1.5 – 2.5 L of water with 70 mmol of sodium and 40 - 80 mmol of potassium • Fluid requirements sometimes classified as that for replacement, maintenance and resuscitation

5. Introduction • Fluid and electrolyte balance consists of : - external balance between the body and its environment - internal balance intravascular, interstitial and intracellular compartments • Twenty four hour requirements in normal adult are 25 – 35 mL/kg or 1.5 – 2.5 L of water with 70 mmol of sodium and 40 - 80 mmol of potassium • Fluid requirements sometimes classified as that for replacement, maintenance and resuscitation

6. Introduction • Crystalloid solutions contain low molecular weight salts or sugars which dissolve completely in water and pass freely between intravascular and interstitial compartments • Colloid solutions contain larger molecular weight substances that do not dissolve completely and remain for a longer period in the intravascular compartment

7. Fluid compartments

8. Fluids

9. Fluids

10. Stress response and fluid • Along with other hormones, stress response to surgery releases vasopressin and triggers the RAAS (renin – angiotensin – aldosterone system) • Net effect is an increase in body water with the retention of sodium and excretion of potassium. Oliguria is common which is accompanied by a reduced capacity of kidney to dilute or concentrate urine • A catabolic state from surgery results in an increased production of urea and other metabolites which compete with electrolytes (mainly Na+ and Cl-) for excretion by the kidney • Recovery phase is characterised by a diuresis with loss of both sodium and water

11. GIFTASUP • GIFTASUP (October 2008) - British Consensus Guidelines on Intravenous Fluid Therapy for Adult Surgical Patients • A 1997 UK study showed that postoperative patients were frequently in positive fluid balances of 7 litres or more with a sodium load of 700 mmol • In the US, excessive fluid administration causing pulmonary oedema has been blamed for 8315 patient deaths a year • A postal survey of 710 consultant surgeons revealed that PRHO’s were most commonly responsible for fluid prescription

12. GIFTASUP Recommendation 1 Normal Saline is Abnormal Recommendation 2 Dextrose can be dangerous Recommendation 3 Equal electrolytes by any route NB – words in red are an aide memoire and do not form part of the GIFTASUP document

13. GIFTASUP Recommendation 1 (Normal Saline is Abnormal) Evidence level 1b Because of the risk of inducing hyperchloraemic acidosis in routine practice, when crystalloid resuscitation or replacement is indicated, balanced salt solutions e.g. Ringer’s lactate/acetate or Hartmann’s solution should replace 0.9% saline, except in cases of hypochloraemia e.g. from vomiting or gastric drain

14. GIFTASUP Normal Saline is Abnormal • 0.9% saline contains supranormal amounts of Na+ and Cl- (154 mmol/L each ) compared to physiological concentrations (140 and 95 mmol/L respectively) • A sodium load can be difficult to excrete especially in the oliguric phase of the stress response • Hyperchloraemia causes renal vasoconstriction and a reduced glomerular filtration rate • Excess serum sodium can aggravate interstitial oedema caused by capillary endothelial leaks

15. GIFTASUP Recommendation 2 (Dextrose can be dangerous) Evidence level 1b • Solutions such as 4% /0.18% dextrose/saline and 5% dextrose are important sources of free water for maintenance, but should be used with caution as excessive amounts may cause dangerous hyponatraemia, especially in children and the elderly • These solutions are not appropriate for resuscitation or replacement therapy except in conditions of significant free water deficit e.g diabetes insipidus

16. GIFTASUP Recommendation 3 (Equal electrolytes by any route) Evidence level 5 • To meet maintenance requirements, adult patients should receive sodium 50-100 mmol/day, potassium 40-80 mmol/day in 1.5 - 2.5 litres of water by the oral, enteral or parenteral route (or a combination of routes) • Additional amounts should only be given to correct deficit or continuing losses. Careful monitoring should be undertaken using clinical examination, fluid balance charts, and regular weighing when possible

17. Curve A represents the hypothesized line of risk. Broken line B represents a division between patient groups in a ‘wet vs dry’ study. Broken line C represents a division between patient and groups in an ‘optimized vs non-optimized’" study M. C. Bellamy Wet, dry or something else? Br. J. Anaesthesia 2006 97: 755-757

18. Oesophageal Doppler

19. LiDCO Rapid

20. GIFTASUP Postoperative fluid management • Details of fluids administered must be clearly recorded and easily accessible • When patients leave theatre for the ward, HDU or ICU their volume status should be assessed • In patients who are euvolaemic and haemodynamically stable a return to oral fluid administration should be achieved as soon as possible • In patients requiring IV maintenance fluids, these should be sodium poor and of low enough volume until the patient has returned their sodium and fluid balance over the peri operative period to zero

21. Scenario 1 80 yr old female for elective total hip arthroplasty Scheduled last on PM list but starved from 1800 hrs previous day Start Hartmann’s 1 litre to run over 6 hours

22. Scenario 2 • yr old male on ward after elective hemi colectomy 6 hrs prior Urine output 50 mls in the last 3 hours Check vitals Look for overt signs of bleeding Fluid challenge 250 mls crystalloid or colloid

23. Scenario 3 27 yr old postoperative lap appendicectomy. No overt losses and patient looking well Oral intake planned as sips of water next day Maintenance fluid – aim for 1.5 – 2.5 L of water with 70 mmol of sodium and 40 - 80 mmol of potassium. Hartmann’s / Dextrose saline with potassium chloride

24. Scenario 4 60 yr old male AP resection 4 days ago. Hypotensive but feels warm to touch, anuric for last 5 hours Check vitals and temperature Judicious fluid challenge Seek senior help early

25. Resources • Association of Surgeons of Great Britain and Ireland http://www.asgbi.org.uk • Intensive Care Society http://www.ics.ac.uk • NICE guideline (nutritional support) http://www.nice.org.uk/Guidance/CG32 • Surgical Tutor http://www.surgical-tutor.org.uk/default-home.htm?principles/postoperative/fluid_balance.htm~right

26. Summary • Fluids are distributed into various body compartments according to their solute molecular weight and content • Normal saline is abnormal • Fluid type and volume must always be tailored to clinical condition

27. ‘Every time I learn something new, it pushes some old stuff out of my brain’

28. Perioperative Care Preoperative Care • Assessment • Fluid optimisation and nutrition Intraoperative Care • Antibiotic and thromboprophylaxis • Sterilisation, disinfection and antisepsis - Transport, positioning, scrubbing up, instruments, incisions, closures, drains, stomas and sutures Postoperative Care • Drain, fluid and acid – base management, pain, surgical complications and critical care

29. Assessment • Objectives of preoperative assessment • Preoperative assessment clinics Infrastructure Personnel Process Pathways and basic investigations • Special investigations CPX testing

30. CPX

31. CPX

32. CPX Cardio- Pulmonary Exercise Testing (CPET or CPX) • The anaerobic threshold (AT) is the uptake of oxygen (ml/kg/min) at the point when there is a surge in CO2 production during increasing workload • This reflects maximum ability of patient to increase oxygen delivery / consumption and cardiopulmonary fitness • AT > 11 ml/kg/min can be used to categorise patients ‘fit’ for major abdominal surgery • Postoperative mortality can be predicted from AT values and presence of test ECG ischaemia

33. CPX Older, P et al Chest 1999;116:355-362

34. Perioperative Care Preoperative Care • Assessment • Fluid optimisation and nutrition Intraoperative Care • Antibiotic and thromboprophylaxis • Sterilisation, disinfection and antisepsis - Transport, positioning, scrubbing up, instruments, incisions, closures, drains, stomas and sutures Postoperative Care • Drain, fluid and acid – base management, pain, surgical complications and critical care

35. Antibiotic prophylaxis • Principles • NICE guidelines • Department of Health (DH) guidelines

36. Antibiotic prophylaxis Principles • High circulating serum levels of antibiotics at the time of tissue contamination • Usually of limited duration e.g. 24 hours post op • Extended duration (3 days or more) Immunosuppressed patients Malnourished patients Patients with prosthetic implants e.g. heart valves Established postoperative surgical infections

37. NICE guidelines Surgical Site Infection http://www.nice.org.uk/Guidance/CG74 October 2008 Antibiotic prophylaxis • Give antibiotic prophylaxis to patients before: – clean surgery involving placing a prosthesis or implant – clean-contaminated surgery – contaminated surgery • Do not give antibiotic prophylaxis routinely for clean non-prosthetic uncomplicated surgery • Use the local antibiotic formulary and consider potential adverse effects when choosing antibiotics

38. Antibiotic prophylaxis

39. DH guidelines Clostridium Difficile Infection (CDI) : How to deal with the problem http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/ PublicationsPolicyAndGuidance/DH_093220January 2009 Restrictive antibiotic guidelines should be developed by trusts stressing the following recommendations: • Use narrow-spectrum agents for empirical treatment where appropriate • Avoid use of clindamycin and second- and third-generation cephalosporins, especially in the elderly • Minimise use of fluoroquinolones, carbapenems and prolonged courses of aminopenicillins

40. Thromboprophylaxis • Definitions • Aetiology • Methods • NICE / DH guidelines

41. Thromboprophylaxis • Definitions Venous thromboembolism (VTE) is the formation of a blood clot (thrombus) in a vein which may dislodge from its site of origin to cause an embolism Most thrombi occur in the deep veins of the legs; this is called deep vein thrombosis (DVT) Dislodged thrombi may travel to the lungs; this is called a pulmonary embolism (PE) • Aetiology Series of contributing factors called Virchow's triad - alterations in blood flow (stasis) - injury to the vascular endothelium - alterations in the constitution of blood (hypercoagulability)

42. Thromboprophylaxis Methods • Mechanical devices Graduated compression stockings, pneumatic compression devices • Drugs acting on the clotting cascade Heparin unfractionated or low molecular weight (LMWH) - activates antithrombin III Dabigatran etexilate – direct inhibitor of thrombin • Antiplatelet drugs Aspirin, Dipyridamole, Clopidogrel • Drugs indirectly affecting clot formation Dextran 70 • General measures Early mobilisation, foot elevation, hydration

43. Mechanical devices

44. NICE guidelines Venous thromboembolism : reducing the risk http://www.nice.org.uk/Guidance/CG92 January 2010

45. NICE guidelines Care pathwayPatient admitted to hospital Assess VTE risk Assess bleeding risk Balance risks of VTE and bleeding. Offer VTE prophylaxis if appropriate. Do not offer pharmacological VTE prophylaxis if patient has any risk factor for bleeding and risk of bleeding outweighs risk of VTE Reassess risks of VTE and bleeding within 24 hours of admission and whenever clinical situation changes.

46. DH guidelines Venous thromboembolism (VTE) risk assessment http://www.dh.gov.uk/en/Publicationsandstatistics/ Publications/PublicationsPolicyAndGuidance/DH_088215 March 2010 • All patients should be risk assessed on admission to hospital • Any tick for thrombosis risk should prompt thromboprophylaxis according to NICE guidance. • Patients should be reassessed within 24 hours of admission and whenever the clinical situation changes • From 1st June 2010 all NHS Trusts are required to be able to demonstrate that more than 90% of their inpatients receive a Venous Thromboembolism Risk Assessment (VTE RA) on admission to hospital

47. Questions ?