Day 1: Overview Flashcards
what is an anaesthetist
Anaesthetists are perioperative physicians who care for patients before, during, and after their journey through surgery
what does peri mean
around
division of perioperative care
preoperative care
intraoperative care
postoperative care
anaesthesiology
also extends to pain managment (both acute and chronic)
requires meticulous applied knowledge of both basic and clinical science
types of anaesthesia
general anaesthesia
regional/ local anaesthesia
general anaesthesia
-unconscious patient induced, reversible coma
-may be achieved with intravenous or inhalational drugs
-depending on the surgery and/or drugs used, patients may breathe spontaneously or be ventilated artificially
-analgesia usually need to be administered separately
local or regional anesthesia
- a part of the body is rendered insensitive to pain, sensation (and possibly movement) by blocking nerves with a local anaesthetic
- patient is still fully conscious (although sedation may be given)
-specific nerves may be blocked, or whole sections
-includes the neuraxial blocks (spinal and epidural) which block the spinal cord
the triad of general anaesthesia
hypnosis
analgesia
immobility
what does hypnosis mean
loss of consciousness
how is hypnosis achieved
it is achieved with general anaesthetic agents (intravenous and/or inhalations)
typically anaesthesia is induced with IV agents and maintained with inhalations
most of these agents ONLY CAUSE HYPNOSIS and are not analgesic
Anaesthesia
what does anaesthesia mean
without sensation
are general anesthetic agents primarily analgesic
Most general anaesthetic agents primarily induce hypnosis and do not provide analgesia.
How is anaesthesia typically induced?
Anaesthesia is usually induced with intravenous agents.
In what situations is hypnosis increasingly used in anesthesia?
-Siting of invasive lines, particularly central lines.
-Siting of regional nerve blocks, especially brachial plexus blocks.
-Transthoracic echocardiography (TTE) can be conducted as a side room test to evaluate cardiac function.
-Invasive transoesophageal echocardiography (TOE) can be used intraoperatively to monitor cardiac function.
Why is analgesia essential during general anesthesia?
-The body still experiences pain under general anesthesia as most agents only interrupt consciousness.
-Pain activates the sympathetic nervous system, leading to deleterious effects.
-Additional analgesic agents are administered intravenously to ensure patient comfort.
-Strong opioids such as fentanyl and morphine are typically used.
-Regional anesthesia techniques like nerve blocks may also be employed for enhanced pain relief.
What is meant by “immobility” in anesthesia?
“Muscle relaxation” is often synonymous with “immobility.”
Why is immobility crucial for surgical procedures?
Immobility ensures an optimal surgical field for surgical access.
What are paralytic agents, and when are they used in anesthesia?
Paralytic agents, or neuromuscular blockers, are used for surgery in large body cavities like the chest and abdomen.
How do patients receiving paralytic agents typically manage their airways?
Patients receiving paralytic agents are typically intubated and require assisted ventilation.
In what types of surgeries might immobility be particularly important?
Immobility may also be necessary for delicate microsurgery, such as on the retina or brain.
Does deep general anesthesia alone guarantee immobility?
Deep general anesthesia induces muscle relaxation but may not completely halt respiration.
What happens to pain perception under general anesthesia?
Pain perception persists under general anesthesia due to interruption of consciousness only.
Why is adequate analgesia crucial during surgery?
Adequate analgesia is vital for patient comfort and to prevent sympathetic nervous system activation.
How does pain affect the sympathetic nervous system?
Pain activates the sympathetic nervous system, leading to detrimental effects like increased heart rate and blood pressure.
What additional measures are taken to provide analgesia during anesthesia?
Additional analgesic agents, typically strong opioids such as fentanyl and morphine, are administered intravenously.
Which types of analgesic agents are commonly administered intravenously?
Intravenous opioids, such as fentanyl and morphine, are commonly administered for systemic analgesia during anesthesia.
Besides systemic analgesia, what other technique can be used to enhance pain control?
Regional anesthesia techniques, such as nerve blocks, can be used in addition to systemic analgesia to enhance pain control.
What does hypnosis refer to in the context of anesthesia?
In anesthesia, hypnosis refers to the loss of consciousness induced by anesthetic agents.
How is loss of consciousness achieved during anesthesia?
Loss of consciousness is achieved with a combination of intravenous and/or inhalational anesthetic agents.
What is the typical approach to induce and maintain anesthesia?
Anesthesia is typically induced with intravenous agents and maintained with inhalational agents.
Are most anesthetic agents also analgesic?
Most anesthetic agents primarily cause hypnosis and do not inherently provide analgesia.
Can patients be fully awake under regional anesthesia?
Under pure regional anesthesia, such as spinal anesthesia, patients can be fully awake, but sedative medication may be administered if necessary.
What does the term “anesthesia” specifically mean?
The term “anesthesia” specifically means “without sensation,” emphasizing the absence of awareness or perception during the procedure.
the perioperative journey
induction
maintenance
emergency
What steps are taken prior to anesthesia induction?
Prior to induction, the patient is assessed, consent is checked, the theatre is prepared, and equipment is checked.
What is the standard practice regarding intravenous access in adult patients?
Intravenous access is always established in adult patients before anesthesia.
Are pre-induction drugs commonly administered? If so, for what purpose?
Pre-induction drugs, such as sedatives, may be given to provide anxiolysis (A level of sedation in which a person is very relaxed and may be awake)
What is the purpose of pre-oxygenation before induction?
Pre-oxygenation is performed to optimize oxygenation levels before induction.
Which medication is typically administered pre-induction to establish analgesia?
Typically, an opioid such as fentanyl is administered pre-induction to pre-emptively establish analgesia.
What are the methods used for anesthesia induction?
Anesthesia induction can proceed with intravenous or inhalational agents.
How is the loss of consciousness confirmed during induction?
Loss of consciousness is confirmed.
What responsibility does the anaesthetist take on after loss of consciousness?
The anaesthetist assumes responsibility for maintaining the patient’s airway.
Describe the implementation of a definitive airway strategy during induction.
A definitive airway strategy, such as mask ventilation, supraglottic airway, or endotracheal tube, is implemented.
What is the procedure if intubation is required during induction?
If intubation is required, a neuromuscular blocking agent is administered first, with an onset time of 1-5 minutes depending on the drug used. The airway is then secured and checked.
What are the primary methods used for maintaining anesthesia?
Maintenance of anesthesia is typically achieved using inhalational agents.
How can propofol be administered for maintenance?
Propofol can be administered via infusion as an alternative to inhalational agents.
What adjustments may be made to ventilator settings during maintenance?
Ventilator settings may be adjusted if mechanical ventilation is used.
What additional monitoring or techniques may be employed during maintenance?
Additional monitoring or techniques, such as regional anesthesia for analgesia augmentation, may be employed.
What steps are taken before surgery proceeds during maintenance?
Before surgery proceeds, the surgical area is cleaned and prepared, and the WHO Surgical Safety Checklist is implemented.
What is crucial before emergence from anesthesia?
Returning control of respiration to the patient is crucial before emergence.
What steps are taken to return control of respiration to the patient?
Any muscle relaxant is checked for reversal, especially non-depolarizing agents.
How are muscle relaxants handled during emergence?
Respiration and oxygenation are assessed for adequacy, including spontaneous, regular breathing and normal vital signs.
How is the anaesthetic agent managed during emergence?
The anaesthetic agent is discontinued.
What is the procedure for removing airway devices during emergence?
Airway devices, such as endotracheal tubes, are removed either deep or upon awakening.
What are the consequences of too light a plane of anesthesia?
Too light anesthesia can lead to patient awareness or emergence from anesthesia.
What problems can arise from too deep a plane of anesthesia?
Too deep anesthesia can exacerbate side effects of anaesthetic agents.
How did Guedel describe the stages of general anesthesia?
Guedel described 4 stages of general anaesthesia:
Stage 1: “Analgesia” from induction to loss of consciousness
Stage 2: Excitatory phase paradoxical disinhibition (excitement, hiccupping, swallowing, writhing about)
Stage 3: Surgical anaesthesia eyeballs become fixed, diaphragmatic respiration
Stage 4: Overdose: diaphragmatic paralysis, loss of all reflexes death
Are the Guedel stages commonly observed with rapid-acting intravenous agents?
The Guedel stages are not typically seen with rapid-acting intravenous agents.
progressive loss of reflexes
These occur as anaesthesia deepens:
-Voluntary control of eye movement
-Eyelash reflex
-Lid reflex
-Swallowing, retching and vomiting
-Conjuctival reflex
-Muscular tone
-Corneal reflex
-Glottic reflexes and control of respiration
-Pupillary light reflex
How do patients regain consciousness during recovery from anesthesia?
Patients regain consciousness when the anaesthetic agents are discontinued and dissociate from their binding sites in the brain.
Is there a specific antidote for inhalational or intravenous anesthetic agents?
There is no specific antidote for either inhalational or intravenous anaesthetic agents.
What should be checked if muscle relaxation is still present during recovery?
If muscle relaxation is still present, the patient may be fully awake but unable to move; some neuromuscular blocking agents require reversal.
Do opioid analgesics contribute to the depth of anesthesia during recovery?
Opioid analgesics cause sedation and contribute to the depth of anesthesia during recovery.
What effect do opioid analgesics have on respiration during recovery?
Opioid analgesics also suppress respiration during recovery.
postoperative placement
- majority: recovery area before they are transferred to the wards
-day cases: may be discharged home
-special care required: high care or intensive unit or if require monitoring post anaesthetic high care unit (PAHCU)
aims of the preoperative visit
-To formulate an ANAESTHETIC PLAN appropriate for both the patient and the planned procedure
-To understand the patient’s BASELINE PHYSIOLOGIC STATE
-To identify any RISK FACTORS
-To identify any conditions which can be OPTIMISED prior to surgery
-To prepare the patient psychologically
last oral intake: solids and formula milk
6 hours
last oral intake: breast milk
4 hours
last oral intake: clear fluid
2 hours
risk factors for aspiration
- full stomach
- pregnancy
- increased abdominal pressure
*obesity
*ascites
*bowel masses
*bowel obstruction - gastric pathology
*peptic ulcer disease, GORD, hiatus hernia
-renal failure
-autonomic neuropathy in diabetes
systems examined
respiratory
airway
cardiovascular
other relevant systems
specials investigations
Should be guided by patients age, comorbidity and planned procedure
Typical examples
-FBC
-U&E (e.g. hypertension / renal disease / elderly / acutely ill)
-Group and Save / Crossmatch (e.g. major blood loss)
-ECG (e.g. elderly / cardiac pathology / hypertension / ischaemic heart disease)
-CXR (e.g. respiratory and cardiovascular disease, elderly)
-Echocardiography (e.g. valve lesions / cardiac disease_
the ASA classification
I: A normal healthy patient
II: A patient with mild systemic disease and no functional limitations
III: A patient with moderate to severe systemic disease that results in some functional limitation, but not incapacitating
IV: A patient with severe systemic disease that is a constant threat to life and incapacitating
V: A moribund patient that is not expected to live for more than 24 hours with or without surgery
VI: A brain dead patient whose organs are being harvested
E: If the procedure is an EMERGENCY, the physical status is followed by an “E’
