Anesthesia for orthopaedic replacement surgeries Prof.Dr.K.BALAKRISHNAN, Chennai.
Introduction • Some of the common joint replacement surgeries are 1. Hip replacement 2. Knee replacement 3. Shoulder replacement 4. Elbow replacement
Total knee replacement (TKR) and hip fracture coming for replacement are the two most common surgical procedures after the sixth decade of life.
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 and gout.
The challenge…. • Decreased organ function and reserve • Co-morbid conditions • Consequences of polypharmacy
Challenges have been converted into good outcomes… • Better understanding on pathophysiology of aging • Better pharmacotherapy • Safer anaesthetic techniques • Improvements in monitoring • Multimodal analgesia and site specific analgesia • Physiotherapy and early ambulation
Pain is the first enemy to mankind…. And anaesthesiologists are mankind’s guardian angels.
The straw that breaks the camel’s back may be a very small one when the camel is nearing the end of it’s journey !
Pre-operative concerns • Associated injuries • Cause for the fall • Difficulty in assessing cardio respiratory reserve • Osteoarthritis- Medications-NSAIDs
Pre-operative concerns…. • Pre-renal azotaemia • DVT prophylaxis • Diabetes Mellitus • The emotional significance of fracture to the geriatric patient must also be considered.
Preoperative Preparation • Evaluation of the functional cardiovascular reserves may be difficult due to the bedridden state, the confusion encountered, and the fracture. Simple steps (e.g., auscultation, ECG, and chest x-ray) can detect acute decompensation.
Echocardiography if feasible at the bedside and can give useful information about left ventricular and valvular function. • Evaluation of electrolytes and blood count is required; anemia or electrolyte disturbances should be addressed prior to anesthesia induction.
Prophylaxis against DVT • Prophylaxis against deep vein thrombosis after lowerlimb joint surgery is done with low molecular weight heparin starting either post operatively or 12 hours preoperatively .
Intra-operative concerns Regional General anesthesia
The choice of anaesthesia is determined by: i) surgical factors ii) Patients factors iii) Estimates of risk associated with anaesthesia techniques
Regional Anesthesia -Advantages • Stress response to surgery • Intraoperative blood loss • Post-operative hypoxia • PONV • DVT- early mobilization
Regional Anesthesia -Advantages • Preemptive analgesia • Post-operative analgesia Hypostatic pneumonia Pressure sores
Centri Neuraxis Block - Concerns • Coagulopathy • Conscious sedation • Shivering • Technical difficulty • Autonomic dysfunction • -Hypotension • I.V. fluids, • vasopressors, • Diastolic pressure 60 mm Hg
Regional anesthesia techniques - Spinal - Epidural anesthesia - Combined spinal epidural anaesthesia - Femoral and Sciatic nerve blocks (especially in patients with fixed cardiac output in whom a neuraxial block is not preferred due to possible haemodynamic changes specifically profound hypotension).
The alternative option in fixed cardiac output states include segmental epidural, here the titrated doses of local anaesthetic administration and just blocking the segments involved offers the benefits of regional anaesthesia in critically ill patients and at the same time provides stable haemodynamics.
General anesthesia -Pre-operative beta blockade • CAD • Hypertension • Diabetes mellitus • Hypercholesterolemia • Renal dysfunction • Goal: Heart rate between 60-70.
General anesthesia -Pre-Oxygenation • 100% Oxygen • 8 deep breaths • Oxygen flow 10 L per min
General anesthesia -Choice of Anesthetic agent Short acting and less lipid soluble drugs • Propofol • Fentanyl • Rocuronium • Atracurium • Sevoflurane • Isoflurane
Intra-operative monitoring Pulse Oximetry 5 lead ECG-ST analysis Capnography NIBP- IBP Temperature Neuromuscular monitoring Urine output
Blood Transfusion Progressive reaming of femur and resection of the condyles is associated with steady blood loss
Bone Cement- Hypotension The placement of the prosthesis involve the use of methylmethacrylate ( bone cement )
The cementing can cause hemodynamic fluctuations These fluctuations are related to the vasodilatory and mast-cell degranulating properties of the monomeric form of methylmethacrylate
Bone Cement implantation syndrome Bonecementimplantation syndrome (BCIS) is poorly understood. It is an important cause of intraoperative mortality and morbidity in patients undergoing cemented hip arthroplasty and may also be seen in the postoperative period in a milder form causing hypoxia and confusion.
Bone Cement implantation syndrome - Treatment BCIS may be reversible with prompt basic life support and treatment to maintain both coronary perfusion pressure and right heart function. Administer fluid volumes to augment right ventricular preload. Direct acting vasopressors, such as phenylephrine and norepinephrine can be titrated to restore adequate aortic perfusion To improve ventricular contractility and function administer inotropes such as dobutamine.
Fat embolism The high incidence of fat embolism with femoral neck fracture repair and cemented endoprosthesis may contribute to pulmonary dysfunction
Tourniquet in knee replacement Tourniquet inflation: may precipitate heart failure may cause hypotension after release of tourniquet due to: Release of acid products Affected limb getting filled with blood Blood loss
Immediate postoperative care should be directed to supporting oxygenation, controlling pain, and facilitating the patient's return to the baseline mental status by emphasizing orientation. Post-operative care
Pain Pain Pain Pain Pain Post-operative concerns
Postoperative pain therapy is best a multimodal approach. - local anaesthetic infusions through perineural catheters supplemented with analgesics including a combination of paracetamol, tramadol, NSAID(when there is no contraindication) and opioids.
PRINCIPLES No.1: Start with low dose Avoid long acting drugs No.2: Use standing dose regimens No.3: Repeated reassessment of pain relief No.4: Repeated reassessment of side effects No.5: Educate/inspire the care giver
Post-operative concerns • Post operative delirium • Post operative hypoxemia • Hyponatremia • Hypoglycemia
Early Mobilisation Psychological support Peri-operative Sepsis Peri- operative Antibiotics
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.