GA and surgery Flashcards
local anaesthetics
used to treat or prevent pain during or after procedure, simple and quick with fast recovery, pressure and movement still felt, injects/ creams/ gel, epidural or spinal, peripheral nerve block
how does local anaesthetic work
they work by entering the cell binding to the Na+ channel, preventing Na+ transport and thus stopping the conductance through the nerve and preventing the transmission of pain signal to the brain
GA
purpose is to create a loss of awareness and temporary block in gross response to stimuli. It inhibits skeletal muscle contraction and autonomic responses, components= coma and muscle relaxations and analgesia
stages of GA- 1 and 2
1- premedication- provides decreased anxiety, helps with pain relief/ sedation and amnesia, less common
2- induction- IV propofol, +/- sevoflurane and +/- intubation
stages of GA- 3 and 4
3- maintenance- when surgery starts, continuation of anaesthetic, IV analgesics and muscle relaxants
4- reversal- begins before the surgery has finished with the reduction in the anaesthetic drugs and reversal of paralysis with neostigmine
effect of GA on respiratory system
GA has a detrimental effect on respiratory function, FRC lowered which encroaches on CV and reduces lung compliance, increases airway resistance and leads to atelectasis, dependent lung collapse within 15 mins of induction, risk of absorption atelectasis, inhalation of dry/cold gas increase mucous viscosity and affects surfactant production, impaired CNS regulation of breathing leading to hypoventilation+supine position= atelectasis, handling pleura has negative effect on diaphragm function
other GA complications
decreased CO, nausea and vomiting, urine retention and constipation, anaphylaxis, MI and CVA, awareness during anaesthesia
common surgery seen in cardiorespiratory physio
general, thoracic, cardiac, vascular, head and neck, breast
cardiorespiratory complications of surgery- atelectasis
pain, position (effects FRC), drowsiness- immobile- reduced depth of breathing and FRC, disruption of diaphragm, pleural effusion, higher effect on upper abdominal and thoracic surgery, atelectasis leads to more atelectasis
cardiorespiratory complications of surgery- hypoxaemia and chest infection
hypoxaemia- decreased hypoxic vasoconstriction because of anaesthetic gases, atelectasis, oxygen hungry= REM stage of sleep affect- oxygen saturation drops especially at night
chest infection- normal to have increased temp post op for 38 hours, anything more= infection
other complications of surgery
pain, anxiety/stress/depression, fatigue, nausea, urine retention/constipation, wound infection- needs to be quickly identified and treated quickly, cognitive dysfunction, haemorrhage, DVT/PE, nerve injuries, fluid imbalance, hypothermia, hypertension
aim of PT in surgical patient- increased lung volume and clear secretions
lung- mobilize/exercise, positioning, breathing exercise, adjuncts
clear secretions- mobilise/exercise, positioning, breathing exercises, adjuncts
aim of PT in surgical patient- to rehabilitate and promote independence
mobilise/exercise, ADL, home visits, post-op rehab
pre-rehabilitation of prehab
a proactive approach designed to enhance functional capacity of an individual to enable them to withstand the stresses of surgery, associated with lower post-op complications and earlier restoration of functional state, MDT approach= nutrition/ psychological and behavioural, programme= personalised
post-op complications of surgery of GA
chest- atelectasis and infections, wound complications, pulmonary oedema, cardiovascular problems and MI, shock, DVT, acute renal failure, reduced gut motility, nausea/vomiting, psychosis, nerve damage, pressure sores, tooth loss or chipping
vascular surgery
aneurysm or atherosclerosis, common ones are abdominal aortic aneurysm (AAA), aortic bifemoral and thoracic aortic aneurysm (TAA)
what is an aneurysm and atherosclerosis
they are a result in the degeneration of the media and elastic lamina of an artery wall- bulges and weaknesses at risk of rupturing, atherosclerosis leads to blocking of the artery which can lead to tissue death
AAA
major occur below the renal arteries, open or trans femoral/endovascular procedures, open=horizontal or vertical incision, cross clamping above and below the affected area and inserting Dacron tubing, carries an 80% mortality rate, monitoring of size in electives consider operation if >5cm
Transfemoral or endovascular- AAA
transfemoral or endovascular (EVAR)= avoids extensive abdominal incision, minimises clamp time and reduced risks of GA as done under local
thoracic aortic aneurysm
less common, some patients with an AAA will have a thoracic extension, often need an aortic valve replacement as well, open surgery or thoracic endovascular aortic repair (TEVAR)
thoracic aortic aneurysm- 4 types
type 1- affects descending thoracic and proximal abdominal aorta, type 2- affects all descending and abdominal aorta, type 3- affects distal thoracic and all of the abdominal aorta, type 4- affects upper aorta from which the visceral arteries arise
aortobifemoral bypass- aortobifemoral
performed in patients with atheroscleoric disease of the infrarenal aorta and iliac arteries. patients have symptoms of claudication, impotence and poorly healing ulcers, examination usually reveal absent or very weak femoral pulses
head and neck
commonly cancer related (squamous cell carcinomas), tumours may involve- oral cavity/ oropharynx/ larynx and hypopharynx, partial and radical neck dissections, laryngectomy
head and neck- procedures may include
split skin grafting, musculocutaneous flaps (pec minor), radial forearm flaps, fibula free flaps, rectus abdominius flaps, organ transposition
head and neck- common post op chest complications
nature of surgery, at risk of aspiration, tracheostomy (temporary or permanent), long surgery, previous health state (smokers, excess alcohol, nutritionally poor)
intercostal drains (ICD)-
used to restore normal sub-atmospheric pressure in pleural space by allowing air and fluid to escape, this allows underlying lung to expand
intercostal drains (ICD)- used for
treating pneumothorax and haemothorax, placed at end of thoracic surgery
how do ICD works
as pressure change surface level of fluid in collection tube swings, air bubbles out but can’t pass under the water to get back into pleura, if air bubbles through drain it indicates a leak in the visceral pleura and the drain is still required, as lung fully re-expands bubbles gradually stops
ICD- handling
when handling patient keep drain below level of chest, avoid-disconnecting kinking stretching tube, observe changes- drainages and air leaks, normally not clamped but look out for this especially if considering positive pressure based treatment
ICD placement- apical and basal
apical- more anterior drain is apical. It drains air
basal- more posterior is baal and drains fluid
the drains are placed on gravity taking the blood lowermost and air rising. ICD’s must never be placed above chest level or liquid contents will siphon into the pleural space
