regional vs. general anesthesia in hip surgery
TRANSCRIPT
REGIONAL VS. GENERAL ANAESTHESIA
IN TREATMENT OF HIP FRACTURE
CONTENTS
Why this topic? Why choose this topic? General information Regional anaesthesia and its modes of usage Common anaesthetic agents used How do the anaesthetics work Comparing the side effects of the different types of
anaesthesia Differences seen and their likely explanation Comparison mortality rates Cochrane evidence Patient’s perspectives Anaesthetist’s perspectives References
WHY THIS TOPIC? Hip fracture management forms large bulk of work in
orthopaedics
Prediction to be 6.3 million cases globally by 2050, Approx 80,000 per year in UK (65,000 in over 65’s)
Anaesthesia is of prime importance in the active management
Mainly affects the elderly female population with intercurrent illnesses- importance of the appropriate anaesthesia
WHAT IS ANAESTHESIA ?
‘Anaesthesia aims to ensure hypnosis, amnesia, analgesia, relaxation of skeletal muscles with loss of control of reflexes of the autonomic nervous system’
GENERAL INFORMATION Regional anaesthesia
Applicable large parts of the body
Divided into central and peripheral
Neuraxial blocks – epidural anaesthesia and spinal anaesthesia
Peripheral - plexus blocks and single nerve blocks
Regional anaesthesia- spinal injection of LA or epidural , often used with sedatives
GA induced and maintained by a number of drugs- dependent on the anaesthetist preference with appropriate airway
REGIONAL ANAESTHESIA
Epidural Spinal
REGIONAL ANAESTHESIA FOR NOF REPAIR
Comparing psoas compartment catheter and epidural catheter
Psoas compartment catheter Epidural catheter
COMMON ANAESTHETIC AGENTS FOR HIP SURGERY
Spinal anaesthesia in hip surgery- lidocaine, mepivacaine, bupivacaine, ropivacaine,
tetravacaine
Lumbar epidural anaesthesia in hip surgery – 2- Chloprocaine, lidocaine, etidocaine, mepivacaine,
bupivacaine, ropivacaine
General anaesthetic – with inhalational, intravenous anaesthetic agents
HOW DO LOCAL ANAESTHETICS WORK?
Reversible interruption of the conduction of impulses in peripheral nerves
Blockade of Sodium channels- impairing sodium flux across the membrane, to some extent on Potassium channels also
Main effect – local decrease in rate and degree of depolarisation- threshold potential not reached and electrical impulse not propagated
No effect on the resting or threshold potential, however refractory period and repolarisation may be prolonged.
HOW DO LOCAL ANAESTHETICS WORK?
HOW DO GENERAL ANAESTHETICS WORK?
The exact mechanism is not known despite of its usage for more than 150 yrs.
Structure is related to ether, the original anaesthetic
Primary site of action is on the CNS- inhibit nerve transmission- reduction in nerve transmission at the synapses
Potentiated by 2 main receptors;
GABA-A- Potentiated by halothane, etomidate and propofol NMDA- inhibited by ketamine
Inhalation anaesthetics e.g. sevoflurane- main action on brain
SIDE EFFECTS OF ANAESTHESIA Epidural
Hypotension- commonest side effect, esp imp for cardio problems High epidural block- unintentional Local anaesthetic toxicity- another unintentional side effect Regional anaesthesia- impaired coagulation or poor patient
cooperation Rarely becomes a fully spinal anaesthetic
Spinal
Length of surgery Headache- commonest complaint amongst young patients Rarely- infection
General Anaesthesia
Usually well tolerated Rarely can lead to stroke or myocardial infarction Aspiration – prevented by endotracheal tube insertion
EVIDENCE COMPARING REGIONAL VS. GENERAL
Meta-analysis by Urwin S.C et al.
Previous meta-analysis of 11 trials showed no overall advantages in one anaesthetic over the other
In terms of risk of DVT and survival at one month- Regional better than General anaesthesia
Results not applicable to all settings due to underlying morbidity not being considered
DIFFERENCES SEEN AND LIKELY EXPLANATION
Risk of DVT
Risk of intraoperative hypotension – no significant reduction with either method
Risk of pulmonary embolism(fatal and non-fatal)- reduced incidence of fatal PE and major thromboembolism with regional
Risk of other conditions- pneumonia, urinary retention,CCF, post-operative vomiting and nausea- no significant differences seen
EXPLANATION OF DVT
Spinal group risk of DVT – 30% GA group- 47%
N.B- venography was used in the cases in which patients had DVT
Reduced sympathetic tone to the lower limbs with increased venous blood flow
Alteration in viscosity and coagulability of blood- regional anaesthesia
OTHER DIFFERENCES SEEN
GA associated with small but significant reduction in the length of the operation
Non-significant tendency for greater confusion following GA
Reduced tendency of CVA after GA is due to a more stable perioperative blood pressure
IV therapy+ vasoconstrictor agents during regional anaesthesia could reduce the adv of GA
Regional anaesthesia has marginal advantages
MORTALITY AND MORBIDITY RATES
Mortality - important post-operative concerns
Flawed methodology in studies included in Cochrane analysis
Valentin et al.- 1968 prospective study looking at the mortality of 578 patients post-op repair of NOF
30 days after surgery the mortality was 6% -spinal and 8%- general anaesthesia
6months to 2 years post-op- the mortality was identical
No differences with respect to ambulation and discharge
COMPARISON OF MORBIDITY CONTD.
Estimated blood loss was smaller (P < 0.05) in patients receiving spinal anaesthesia
high short-term mortality was related to age, male sex, and trochanteric fracture
long-term mortality was related to male sex and high ASA scores.
COCHRANE EVIDENCE Cochrane analysis done in 2009
Primary outcome was mortality
8 trials decreased mortality at one month with regional anaesthesia 6.9% vs. 10.0% with general anaesthesia
Reduced risk of DVT; Regional (30%) versus general (47%)
Regional assoc with reduced risk of acute postoperative confusion 9.4 % vs. 19.2 %
Flawed methodology- biased sample of patients
PATIENT’S PERSPECTIVE Awareness is of the main concern that patients have
Mashour et al. 2009 – no statistical difference in intraoperative awareness
Intraoperative awareness complaints in GA 0.023% vs. Regional anaesthesia 0.03%
Complete unconsciousness is often the expectation of the patient
Often the communication between anaesthetist and patient is seen to be inadequate in patient’s experience
Rehabilitation is often seen to be quicker with regional anaesthesia when compared with general anaesthesia
ANAESTHETISTS’ PERSPECTIVE‘One of the hardest anaesthetic lists to do’- CT2 Anaesthetist
The main reason being the comorbidities present in the patients
This makes monitoring of the patient challenging
The final decision is up to to the anaesthetist in terms of the route of administration
Donati et al. BJA 2004 - operative risk of 4000 patients.
The risk for ASA (American Society of Anaesthesiologists) 4 , Age>70,
Elective surgery was 3.7 %
Urgent/emergency it was as high as 16.7%
CONCLUSIONS There are various methods of
anaesthesia for the repair of hip fracture
Better trials with the unbiased sample, and better follow up is needed
Various factors determine the chosen method- patient, anaesthetist and surgeon
All aim for early patient mobilisation following operation
REFERENCES1. Melton Hip fractures; a worldwide problem today and tomorrow
Bone 1993;14 (Suppl. 1): S1-8
2. General versus regional anaesthesia for hip fracture surgery: British Journal of Anaesthesia 84 (4): 450–5 (2000).
3. Mashour GA, Wang L, Turner CR, Vandervest JC, Shanks A, Tremper KK. A retrospective study of intraoperative awareness with methodological implications. Anesth Analg 2009;108:521–6
4. N. Valentin, M.D.,B. Lomholt, M.D., J. S. Jensen, DR MED. SC., N. Hejgaard M.D. and S. Kreiner, Cand. Stat. Spinal or General Anaesthesia for surgery of the fractured hip? A Prospective Study of Mortality in 578 Patients. Br. J. Anaesth. (1986)
5. Dr K Balakrishnan ; Care of the patient with fracture neck of femur for non-emergency surgery.
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