ANESTHESIA FOR THR & TKR

Aftab HussainAftab Hussain

Case Scenario

• Mr. X is 83yr old retired bank manager, who had osteoarthritis of his right hip requiring total hip replacement.

• Prior to surgery he had difficulty in walking and was in constant pain, requiring chronic pain management.

• He has history of HTN and renal insufficiency.

He was operated under regional anaesthesia and was uneventful. Post op pain was controlled by epidural top up injections.

He has b/l sequential compression stockings

applied to his lower legs post operatively.

• Total knee replacement (TKR) and hip fracture coming for replacement are the two most common surgical procedures after the sixth decade of life.

Introduction

• What are the conditions requiring hip/knee replacement ?

• Most of the patients have degenerative joint disease, commonly osteoarthritis (OA).

Other conditions requiring knee or hip replacement are -

• injury to the neck of femur or knee joint, • knee deformity, • rheumatoid arthritis • Gout• Hemophilia

Joint replacement is performed to relieve -• pain and • morbidity.

• What are the challenges associated with THR/TKR patients ?

The challenge….

• Decreased organ function and reserve• Co-morbid conditions• Consequences of polypharmacy

• What are the preoperative preparation ?

Preoperative Preparation

Evaluation of the functional cardiovascular reserves

• Simple steps (e.g., auscultation, ECG, and chest x-

ray) can detect acute decompensation.

• Echocardiography if feasible at the bedside.• Evaluation of electrolytes and blood count is

required

Renal Function – may be impaired d/t age, HTN or chronic use of NSAIDS.

• What are the implication of musculoskeletal examination in these patients ?

Musculoskeletal system -• other joint involvement is common which

have implications for positioning for regional anaesthesia & surgery.

• Rheumatoid Arthritis – cervical spine involvement TMJ involvement

Atlantoaxial Subluxation

Cord compression or vertebral artery compression on excessive movement of neck

Neck stabilisation or awake intubation

TMJ involvement

Restricted mouth opening

Difficult Intubation

Regional Anaesthesia is better option

H/o Drugs – . If patient is taking warfarin, aspirin, clopidogrel

More chances of hematoma formation in regional anaesthesia

. Beta blockers – can be continued

• What are the investigations required ?

Investigations - Blood Counts Renal function test ECG Blood Grouping Coagulation Profile Chest X-ray

The choice of anaesthesia is determined by:i) surgical factorsii) Patients factorsiii) Estimates of risk associated with

anaesthesia techniques

Choice Of AnaesthesiaChoice Of Anaesthesia

• Name anaesthetic techniques for THR ?

• THR – 1. Regional Epidural Combined spinal epidural

2. General Anaesthesia

Spinal

• Name anaesthetic techniques for TKR ?

TKR – 1. GA with femoral & sciatic nerve block2. Femoral & sciatic n. block alone3. General Anaesthesia4. Spinal5. Epidural6. Combined Spinal Epidural

Anaesthesia

SPINAL

If no contraindication

Preload with IV fluid before performing spinal. In TKR Avoid excessive preload before

performing spinal

• For a single shot spinal use 2.5 – 3.0 mls of 0.5% bupivacaine depending on patient size.

• Adjuvants added to prolong effect of spinal anaesthesia ?

• Opiate may be added for more prolonged analgesia and to cover longer surgery (up to 3 hours).

Opioid Dose Duration of action

Diamorphine 250 mcg 10-20 hrs Morphine 100-200mcg 8-24 hrs Fentanyl 25mcg 1-4 hrsButorphenol 50-100 mcg 2-3 hrs

• Light sedation using increments of midazolam 0.5mg or low dose target controlled infusion of propofol may be used.

• For long cases – Epidural & combined spinal epidural

PERIPHERAL NERVE BLOCKS

• Peripheral nerve blocks employing long-acting anesthetics or catheters may provide excellent intraoperative anesthesia and superior postoperative analgesia.

• Why is peripheral nerve block technically difficult to perform in THR ?

Peripheral nerve blocks for total hip replacement

The hip joint is innervated by the femoral, gluteal

and obturator nerves with skin and superficial tissues receiving branches from the lower thoracic nerves. Consequently no single peripheral nerve block is sufficient for hip replacement.

Lumbar plexus block provides effective analgesia which extends into the postoperative period.

The femoral 3 in 1 block, technically easier

• Peripheral nerve block for TKR ?

Peripheral nerve blocks for TKR

• Femoral (3 in 1) blocks have become popular and provide good analgesia in the first 12-24 hrs.

• They avoid the need for a urinary catheter in most patients and allow mobility in bed.

• They need 30 minutes to become effective

and do not provide surgical anaesthesia.

• Femoral 3 in 1 block … ?

• Historically femoral nerve block was thought to block femoral, lateral femoral cutaneous nerve and obturator nerve.

• Most of the time obturator nerve is not blocked.

• What are the advantages of regional anaesthesia ?

Regional Anesthesia -AdvantagesRegional Anesthesia -Advantages

Stress response to surgeryStress response to surgery Intraoperative blood lossIntraoperative blood loss Post-operative hypoxiaPost-operative hypoxia PONVPONV DVT- early mobilizationDVT- early mobilization

GENERAL ANAESTHESIA

• Spontaneous ventilation via LMA

• Ventilation via endotracheal tube

• What are the advantages of general anaesthesia ?

General Anaesthesia -Advantages

• Better for patients who are unable to lie flat.

• Safer for patients with fixed cardiac output

states such as aortic stenosis.

• Patient preference.

• Less likely to require urinary catheterisation.

• Monitoring requirement ?

Perioperative…

Monitoring – NIBP ECG PULSE OXIMETER CAPNOGRAPH URINE OUTPUT

Difficulties associated with positioning in…

• THR ?

• TKR ?

Position –

• In THR position is lateral. There is a

risk of excessive lateral neck flexion and pressure in the dependent limb.

• In TKR patient is supine & airway

control can be a problem if sedation is used.

• What is the use of tourniquet in TKR and morbidity associated with it ?

• Risks associated with tourniquet deflation ?

Tourniquet - Used in TKR so perioperative blood loss is not a

problem until its release. Tourniquet pain occur after about 1 hr causing

increased HR & BP (GA) and it can occur even with

regional anaesthesia.

Tt – deepen anaesthesia opioids

Tourniquet deflation• After deflation of the tourniquet a short-lived

reperfusion event commonly occurs.

• Acidic products of metabolism are washed out

of the limb causing peripheral vasodilatation

and reduced cardiac contractility, both of

which result in a drop in blood pressure.

• End-tidal CO2 rises and a fall in oxygen saturation is often seen.

• Prevention involves fluid loading before and

during tourniquet release. Additional oxygen and vasopressors may be required.

• Fluid balance –after release of the tourniquet most blood loss occurs in the recovery area. Careful fluid balance is essential as hypovolaemia is poorly tolerated in elderly patients.

• Check haemoglobin 24 hours postoperatively and treat with iron as necessary. Blood transfusion is required only rarely.

• Antibiotic prophylaxis .. When ?

Antibiotic Prophylaxis Infection is one of the most common

complication after THR & TKR. So all patients should receive antibiotic prophylaxis.

Administered within 1 hr prior to skin incision.

If tourniquet is to be used, should be given prior to tourniquet inflation.

• Post op care ?

Immediate postoperative care to support

oxygenation,

controlling pain, and

early mobilisation

Post-operative care Post-operative care

• Effective post op analgesia is essential for early physical rehabilitation to maximize postoperative range of motion and prevent joint adhesions.

• Patients usually undertake passive exercises in the operated leg within 24 hours and are mobilized at 48 hours.

• Postoperative pain therapy is best a

multimodal approach.

• regular paracetamol and a NSAID.

• Parenteral opioid may be administered to

supplement peripheral nerve blocks as

necessary.

• Oxygen therapy for 24 hours is advisable in most patients, continued up to 72 hours in those at high risk of myocardial ischaemia.

• What are the complications associated with THR/TKR ?

COMPLICATIONS• Blood loss –

• In THR The average loss is 300-500mls (reduced by centroneuraxial techniques). A similar amount may be lost in the drain and tissues postoperatively.

• In TKR Blood loss may be brisk after deflation of the tourniquet, and if it exceeds 500 mls the surgeon may clamp the drain for a period.

Venous Thromboembolism

• More common in TKR than THR• Clinical DVT occurs in 10% of patients

without prophylaxis and fatal pulmonary embolism in 0.4% of patients.

• Strategies to prevent Venous thromboembolism ?

• Strategies to minimise risk include - .avoiding dehydration, .early mobilisation, .regional anaesthesia, .intermittent leg-compression devices, .graduated compression stockings.

• Prophylaxis for DVT ?

Prophylaxis against DVT

• Low dose heparin, low molecular weight heparin (LMWH), warfarin, or the selective factor Xa inhibitor, fondaparinux are effective in reducing DVT.

• concern about possible bleeding complications

• Recommendations allow a 12 hour interval between low molecular weight heparin and epidural/spinal injection. This also applies to removal of an epidural catheter.

• What is cement reaction (BCIS)?

Cement Rxn - BCIS• More common in THR• Use of cement to fix the prostheses in place

may lead to bone cement implantation syndrome(BCIS).

• Methylmethacrylate is an acrylic polymer. • Its use is associated with the potential for

hypoxia, hypotension and cardiovascular collapse including cardiac arrest.

• The most likely cause is fat embolization

FAT EMBOLISM

• The high incidence of fat embolism with femoral neck fracture repair and cemented endoprosthesis may contribute to pulmonary dysfunction.

• Strategies for prevention and treatment of BCIS ?

Prevention and treatment • Increased inspired oxygen concentration prior

to cementing • Measure blood pressure frequently at this

time • Ensure adequate blood volume prior to

cementing • Stop N2O • Alpha agonists (epinephrine) to treat

hypotension• In case of severe cardiac disease use of

cement should be avoided.

• High pressure pulsatile lavage of femoral canal.

• Drilling a vent hole in the femur before prosthesis insertion.

• SBTKR ?• Advantages and disadvantages?

• SBTKR -- Simulataneous B/l, TKR

• Advantages and disadvantages?

• Advantages:One anaesthetic exposurePostop pain courseReduced rehabilitationEarlier return of baseline function

• DisadvantagesIncreased perioperative complicationsMore blood transfusionsRisk of ICU admissions.

Conclusion

• Geriatric patients for joint replacement surgeries offer a great challenge to the anaesthesiologists.

• A careful preoperative examination, preoperative optimization, safe intraoperative anaesthetic techniques, good postoperative pain relief, good postoperative followup with rehabilitation would aid in decreasing the morbidity in these patients.

THANK YOU