Transcript ch09 anaesthetics

By Justine Barry 3rd year student (October 2008)
For many children and young people having surgery, this may be their first and only experience of a hospital
environment. Admissions must be carefully planned to avoid any distress to the child and family, so care
needs to be provided by staff who are educated in the needs of the child/young person and their carers
(RCN 2004).
Recommendations by the Royal College of Nursing suggest:
 Specialist knowledge is needed to assess, plan, evaluate and implement the care required to meet the
needs of the child/young person and family.
 Information must be pitched at a correct level to patient and parent so they can make an informed choice
about the procedures.
 The nurse must ensure the parent understands what to expect at the time of induction, offer support
during and after this procedure, and keep them fully informed of progress.
The aim of this presentation is to provide a basic introduction to anaesthetics so you can relate
this to your practice on the ward. This will help you understand the need for
Pre and post operative observations, to gain a better understanding
of drugs used in theatres and become familiar with the MDT’s involved.
Justine Barry 2008
•
The word anaesthesia means the
loss of the sensations of touch,
pressure, pain and temperature in
any part of the body, or in the whole
of it.
•
Anaesthesia can be given in various
ways and does not always make
you unconscious; it can just be used
to stop pain in an area of the body,
this is called a local anaesthetic.
•
A general anaesthetic is used
when you need to be in a state of
controlled unconsciousness and
free of pain during a test or
operation. A combination of drugs
given either as gas to breathe into
the lungs, or as an injection (NHS
2008).
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“The Triad of Anaesthesia was developed to describe the three basic requirements of an
anaesthetic that must be achieved to ensure a successful outcome”. (Davey 1999, pg 143)
Hypnosis –
Refers to the alterations in the patient’s conscious
-ness. General anaesthetics are given to render the
patient unconscious, whereas with local
anaesthetics a sedative may be given to produce a
state of drowsiness.
Hypnosis
AnalgesiaRefers to the use of drugs and other techniques
used to ensure the patient recovers with as little pain
as possible and to also suppress the physiological
reflexes, that occur following surgical stimulation.
Relaxation –
refers to the need for reduction or elimination of
muscle tone, which can be retained even when the
patient is unconscious. Muscle relaxants are
necessary for certain types of surgery or procedures
i.e. intra-abdominal surgery and intubation.
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Analgesia
Relaxatio
n
(Davey 1999)
ANAESTHETICS: HOW THEY WORK
Type
Names
Administered
Affect
General
Halothane,
Sevoflurane,
Isoflurane,
Ketamine, Nitrous
Oxide, Thiopental
Intravenously,
Inhalation
Produces total unconsciousness affecting the entire
body
Regional
Bupivacaine
Chloroprocaine,
Lidocaine
Injection
Temporarily interrupts transmission of nerve impulses
(temperature, touch, pain) and motor functions in a
large area to be treated; does not produce
unconsciousness
Local
Procaine,
Lidocaine,
Bupivacaine
Injection
Temporarily blocks transmission of nerve impulses and
motor functions in a specific area; does not produce
unconsciousness
Topical
Benzocaine,
Lidocaine Dibucaine,
Pramoxine,
Butamben, Tetracaine
Dermal (Sprays,
Drops,
Ointments,
Creams, Gels)
Temporarily blocks nerve endings in skin and mucous
membranes; does not produce unconsciousness
KRAPP (2002)
Justine Barry 2008
Information is moved around the brain,
from nerve cell to nerve cell, by means
of chemical substances, called
neurotransmitters
1
A message travels along the nerve and when it approaches
the nerve ending a neurotransmitter is released.
2
The neurotransmitter is received by the next cell
3
some of the neurotransmitter gets reabsorbed
4
When enough neurotransmitter is received by the next
nerve cell the message moves forward
The activation of a nerve impulse is an electrical phenomena in which
a series of connected nerve fibres are sequentially polarised and
depolarised. A nerve impulse is passed from one nerve cell to the other
across the cleft by a "neurotransmitter".
message
Next nerve cell
neurotransmitter
This voltage comes about due to the differences between the ionic
composition of inside the cell (where potassium ions, K+, are in higher
concentration) and outside the cell (where sodium ions, Na+, are in
higher concentration). When stimulus is applied to these cells, Na+
ions flow into the cell, voltage increases, thereby causing K+ to flow
out of the cell. This change in voltage is referred to as depolarization.
Local anaesthetics - act by preventing the normal depolarisation/re-polarisation of nerve cells. Local anaesthetic
drugs do this by blocking conduction of the electrolytes and therefore block the normal action of the nerve.
After absorption of the drugs into the systemic circulation, metabolism occurs either in the liver or in the plasma
and the drug is then excreted by the kidneys (O’Neil 2006).
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(Grant 2006) (http://www.cdhb.govt.nz/totara/brain.htm)
Topical anaesthetic preparations reduce the pain of a venepuncture and facilitates IV induction,
whilst reducing the necessity for sedative pre-medication. (Allman 2006)
The Royal College of Nursing (2004) recommends the use of Emla and Ametop as fear of
needles is always a concern for children and young people
Emla is a mixture of Lidocaine and Prilocaine and is applied over the site under an occlusive
dressing for at least an hour (no more than 5 hours) before the planned procedure. It is usually
applied to at least two sites in case the first attempt fails. (BNFC 2008 and Aitkenhead et al 2003).
Emla is a vasoconstrictor and works by numbing the skin, preventing pain signals passing from the
area of application to the brain.
Side effects include: paleness, redness and swelling of the site. Mild burning, tingling or itching
sensation and methaemoglobinaemia. Should not be used in children under 1 year of age.
Ametop is a local anaesthetic gel which is applied in the same way as Emla,
but is left on the skin for 30 minutes for venepuncture and 45 minutes for
venous cannulation, and lasts for 4-6 hours ( BNF 2008).
Ametop is a vasodilator and works by blocking the message from the pain
receptors to the brain and hence blocks the sensation of pain.
Ametop should only be applied to intact healthy skin and should not be
used on broken skin or open wounds.
Side effects include: flushing of the skin, due to widening of the small blood
vessels (erythema). oedema, pruritis, sensitisation, and blistering of the
skin at the site of application.
Justine Barry 2008
BNFC 2008)
Local anaesthetic drugs are injected near to the set of nerves which carry
signals from that area of the body to the brain (NHS 2008). They reversibly
block nerve initiation and transmission when applied locally to nerve tissue
(O’Neil 2006), blocking nerve fibres with the smallest diameter first (Wood
1998). They are also used to infiltrate surgical wounds at the end of an
operation.
Lidocaine/Lignocaine
Is a quick and short acting local anaesthetic used for surface infiltration, intravenous
blocks and spinal/ epidural anaesthesia. It’s length of action is 1-2 hours.
Side effects include: slurred speech, psychosis, tremors, agitation and difficulty
swallowing.
Bupivacaine/Levobupivcaine
Is a slow and long acting local anaesthetic used for infiltration, intravenous blocks and
spinal/epidural anaesthesia. It’s length of action is 4-8 hours.
Side effects include: Nausea, vomiting, nervousness, disorientation, dizziness and
blurred vision.
www.littonbio.com
Justine Barry 2008
Regional anaesthesia is used for operations on larger or deeper parts of the body. Local
anaesthetic drugs are injected near to the set of nerves which carry signals from that
area of the body to the brain.
“Epidural anaesthesia requires
a fine tube catheter to be left in the epidural
space, through which further injections or an
infusion of anaesthetic drugs can be given. Drugs
can also be given down the epidural catheter
after the operation to provide continuing pain
relief in the postoperative period”
(NHS 2003, pg 16).
Spinal Block Spinal anaesthesia is a major form of regional
anaesthesia, performed by injecting an anaesthetic drug between two
of the vertebrae of the lower back into the fluid between the discs. This
blocks the nearby spinal nerves, causing a complete loss of feeling
from that point down the body (NHS 2008).
Biers Block- Local Anaesthetic is injected into the limb, where the
blood flow is impeded by the application of a tourniquet, the drug is
then rapidly taken up from the venous system by the peripheral nerves
(Anaesthesia UK 2008).
http://surgerycenter.spinalmedicine.com https://healthlibrary.epnet.com.
Justine Barry 2008
General anaesthesia is the induction of a balanced state of unconsciousness,
accompanied by the absence of pain sensation and the paralysis of skeletal muscle over
the entire body. It is induced through the administration of anaesthetic drugs and is used
during major and other invasive surgical procedures (Krapp, K. Cengage, G. (2002).
There are two major types of anaesthetics used for general anaesthesia, inhalation and
intravenous anaesthetics.
Inhalation anaesthetics, which are sometimes called volatile anaesthetics, are compounds that enter the
body through the lungs and are carried by the blood to body tissues (NDA 1998).
The most commonly used anaesthetic vapours used in paediatrics are Sevoflurane, Halothane and
Isoflurane. Inhalation anaesthetics act either by amplifying inhibitory function or decreasing excitatory
transmission at the nerve endings in the brain.
Volatile anaesthetics are seldom used alone, a combination of inhalation anaesthetics and intravenous
drugs is called balanced anaesthesia. Ideally, inhalation agents should provide a quick induction and
emergence from anaesthesia, good analgesia, muscle relaxation, quick changes and easy maintenance
of anaesthesia (Wenker 1999).
Intravenous anaesthetics may be used to either induce anaesthesia or for the maintenance of anaesthesia
throughout a surgical procedure. TIVA is a total intra-venous anaesthesia, a technique where all drugs are
given IV (BNFC 2008).
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Oxygen
Nitrous Oxide
(laughing gas)
is used as a carrier gas
to supplement inhalation agents.
Produces light anaesthesia,
And some analgesia
Sevoflurane
• Most commonly used vapour
• Rapid acting anaesthetic
• Rapid emergence and recovery
• Non irritant
• Pleasant smell
• Produces low levels of respiratory depression.
• Little or no nephrotoxicity.
Justine Barry 2008
inhalation anaesthetics
must be given with
concentrations of oxygen
greater than 21%,
to prevent hypoxia.
Halothane
• Causes unconsciousness,
but provides little pain relief
• Induction is smooth and
vapour is usually non-irritant,
rarely induces coughing or
breath-holding.
Isoflurane
• rarely used vapour as
Sevoflurane has replaced the
use of Isoflurane.
• causes muscle relaxation
• Used to maintain a state of
general anaesthesia.
• Is not widely used as it is
associated with severe
hepatotoxicity.
• can induce irregular heart
rhythms
• Depresses cardiac muscle
fibres, causing bradycardia.
• Systemic arterial pressure
can fall and cardiac output can
decrease.
(BNFC 2008, Krapp 2002, O’Neil 2006)
Justine Barry 2008
Ketamine
Propofol
Most commonly used
induction agent – painful
on injection- rapid recoverycauses significant decreases
in blood pressure
and heart rate,
it also contains anti-emetic
properties
has good analgesic
properties at sub-anaesthetic
dosage and it causes less
hypotension than
Thiopental and Propofol
during induction.
Can cause hallucinations,
Nightmares and
Psychotics effects
Thiopentone
Etomidate
Why not look In
the
British National
Formulary (BNF)
To see more side
effects and the
dosages
Of these drugs.
Rapid recovery- Less
Incidence of hypotension
-no hang Over effects-May Cause muscle spasm on
induction
-Should not be used for
The maintenance of
anaesthesia
Enables smooth, rapid
induction- slow recoveryno analgesic propertiesCardio-respiratory
depression
Can occur
(BNFC 2008)
Guedal’s classification of General Anaesthesia
STAGE 1
begins with the induction of anaesthesia and ends
with the patient's loss of consciousness. The patient still feels
pain this stage.
STAGE 2
Excitement- reflexes remain and coughing, vomiting and
Struggling may occur. Respiration can be irregular with
Breath holding.
STAGE 3 ( divided into four planes)
Plane 1- Eyelid reflex lost, swallowing reflex disappears
Plane 2- eyeball movement ceases, laryngeal reflex lost,
Corneal reflex disappears, secretion of tears increases
Plane 3- diaphragmatic respiration. Pupils dilated
Plane 4 – complete intercostal paralysis
STAGE 4
Medullary paralysis with respiratory arrest and vasomotor
Collapse as a result of anaesthetic overdose. Death may
result if the patient cannot be revived quickly.
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(www.tpub.com, Dougherty 2004)
Drugs are sometimes, given to reduce fear and anxiety in the pre-operative patient,
to relieve pain and discomfort when present, and to increase the action of
anaesthetic agents. Sedative pre-medication is rarely used in day-case patients as
the effects can be unpredictable and can cause excessive drowsiness postoperatively (RCN 2004).
A number of the drugs used also provide some degree of pre-operative amnesia.
The choice will vary with the individual child, the nature of the operative procedure
and the anaesthetic to be used. The choice also varies between elective and
emergency operations. Oral administration is preferred where possible but it is not
altogether satisfactory; the rectal route should only be used in exceptional
circumstances. (BNFC 2008)
“Anticipation of the need for analgesia and pre-emptive treatment should be the
norm” (Doyle 2007, pg 146). The following are common drugs used for paediatric
premedication.
Midazolam
Brufen
Paracetamol
Justine Barry 2008
- (Benzodiazepines) is a oral premedicant commonly used to sedate children and given 30-60 minutes
before the procedure. This sedative relieves anxiety and causes amnesia, useful for reducing the
likelihood of unpleasant memories of the procedure.
- used to treat mild-moderate pain, do not depress respiration or impair gastro-intestinal motility and
don’t cause dependence. They are a useful alternative to opioids (side effects of which include
respiratory and cardiovascular depression) for the relief of post-operative pain. Onset of action
is approx 30 minutes.
- Has anti-pyretic and analgesic properties, do not cause respiratory depression (unlike
opioid analgesics), are less irritant to the stomach than NSAID’s. Given orally, rectally
and intravenously. Onset of action is approx 30 minutes.
(BNFC 2008)
http://labs.ansci.uiuc.edu
Motor end plate
Axon of motor nerve
Muscle fibres
Drugs in this group induce
muscle paralysis by affecting Acetylcholine
(a neurotransmitter) metabolism. Normally, stimulation of a motor
nerve causes the nerve endings to release Acetylcholine, which binds
to the motor-end plate. Depolarisation than occurs and the muscle
contracts. Acetylcholinesterase then metabolises the
Acetylcholine, allowing the muscle to repolarise and relax,
ready for the next contraction (O’Neil 2006, Grant 2006)
Artificial ventilation is required when using muscle
relaxants as they affect the muscles
used for respiration.
Suxamethonium is a depolarising muscle relaxant
Atracuriam is a non-depolarising muscle relaxant which
which means it acts directly on the motor end plate
of voluntary muscles. While this drug remains
attached to the motor end plate, muscle fibres
remain inhibited, so therefore cannot respond to
nerve stimulation. This action causes paralysis in
around 90 seconds and lasts for 2-5 minutes until
the drug Is metabolised by the body. Repolarisation
then occurs, which reactivates the muscle (Wickers
2006). This process Cannot be reversed and
recovery is spontaneous.
Side effects include: flushing of the skin, excessive
salivation, bradycardia, tachycardia, post-operative
muscle pain and prolonged respiratory depression.
acts as a barrier to Acetylcholine, preventing it reaching the
receptors on the motor end plate and causing
depolarisation. The muscle remains paralysed and
unresponsive since the drug nor Acetylcholine can
depolarise the fibres. This action lasts for 15-35 minutes
until the amount of Acetylcholine increases and overcomes
this barrier restoring muscle contractibility. (Wood 1998).
Neostigmine is the specific drug for reversal of nondepolarising blockade. It acts within one minute of
intravenous injection and its effects last for 20-30 minutes a
second dose may then be necessary. Atropine is given
with neostigmine to prevent bradycardia, excessive
salivation, and other effects of neostigmine.
Justine Barry 2008
(BNFC 2008)
Opiates such as Morphine and
Fentanyl, are potent analgesics
which play a major role in the
management of moderate and
severe pain in children. They are
used for reducing pain, anaesthetic
and surgical distress and they are
often used pre, Intra and postoperatively. Opiates can be given via
intramuscular, intravenous,oral
topical and intrathecal routes.
“Analgesics are a complex group
of drugs….they act by either reducing
capacity of the nerve fibres to sense
pain or by reducing pain recognition
by the higher Centres of the brain.”
(O’Neil 2006, pg 109)
The side effects of opiates include:
euphoria, respiratory depression,
depression of the coughing reflex,
nausea and vomiting, reduction of
smooth muscle contraction and
cardiovascular depression.
Paracetamol and Non-Steroidal Anti Inflammatory Drugs (NSAID’s) are
commonly used non-opioids used for managing pain following minor
surgical procedures or when the pain following major surgery begins to
subside.
NSAID’s such as Diclonfenac and Ibuprofen, provide better pain
relief than paracetamol and can be used alone or in combination with
paracetamol and opioids. Side effects of NSAID’s include coagulation
problems,Renal impairment, diarrhoea, nausea and gastrointestinal
disturbances limit their use.
Opiate Antagonists, such as
Naloxone and Nalorphine, support
the patient’s respiratory and
cardiovascular system during
reversal of anaesthesia and postoperative care.
“Paracetamol remains the most popular and widely used prescribed
analgesic and antipyretic and forms the mainstay of almost all analgesic
regimens” (Doyle 2007, pg 156).
Paracetamol has a very good safety record and can be given orally, IV
and rectally. Side effects are rare, but can include: rashes, blood
disorders and hypotension reported on infusion.
(BNFC 2008, Dougherty 2004, Doyle 2007 and O’Neil 2006)
Justine Barry 2008
An Anaesthetist is “A medically qualified doctor who cares for a patient during a surgical
procedure and administers either a general or regional anaesthetic. Anaesthetists also
assess the state of a patient’s health before a planned surgical procedure, and are often
involved in caring for the patient post-surgery. Most specialists in intensive care and pain
management are anaesthetists” (NHS 2003, pg 50).
Anaesthetists are supported in their work by other members of the healthcare team. The following are
just four of the many professionals involved.
Operating Department Practitioners (ODPS) and Anaesthetic Nurse“ are integral to operating
practice and safe, effective care”. (Wicker and O’Neil 2006, pg 243). Their duties include: assisting the
anaesthetist in maintaining anaesthesia, recording fluid balance, transfusions and recording the
patient’s vital signs. (Moss 2007)
Recovery Nurse – is post-operatively responsible for maintaining a safe patient airway, monitoring of
vital signs, checking wound sites, assessing the patients pain level and if necessary, administering
analgesia. After complete recovery, completion of documentation and a concise handover is delivered
to ward staff. (Moss 2007)
Pain Team- are staffed by consultant anaesthetists and registered specialist
nurses offering guidance on pain control for patients with: surgical, medical,
trauma and acute post-operative pain. All patients with epidural analgesia
and morphine infusions are followed up by the pain team. The acute pain
service also provides continuing education and support for the other ward
-based staff who may be involved in the monitoring and provision of
pain relief. (AAGBI 2001)
Justine Barry 2008
“All patients should have had a basic physical examination of the cardiovascular and
respiratory systems conducted by a medical practitioner. The anaesthetic room is not the
appropriate place for an anaesthetist to see an un-assessed patient for the first time prior to
surgery. The hospital system must allow time for patients to be seen pre-operatively by the
anaesthetist. If this is not the case, elective operations may have to be cancelled.
The pre-operative visit also provides an ideal opportunity for teaching trainees and other
healthcare staff about pre-anaesthetic assessment” (AAGBI 2001 pg 4).
The Objectives of Pre-Operative assessment
The aim in assessing patients before anaesthesia and
Surgery is to improve outcome. This is achieved by:
• identifying potential anaesthetic difficulties
• identifying existing medical conditions
• improving safety by assessing and quantifying risk
• allowing planning of peri-operative care
• providing the opportunity for explanation and discussion
• allaying fear and anxiety
Good pre-operative assessment will help to:
• reduce costs
• increase efficiency of operating theatre time
Such action should:
• reduce the number of patients who fail to attend on the day
of surgery
• reduce cancellation of surgery for clinical reasons
Patients should have access to easily understood information.
Such information may be conferred through patient advocates
or via information sheets in an appropriate language.
(AAGBI 2001, pg 6)
“Ward staff, the collecting/receiving staff
from theatres, the Anaesthetist and the
surgeon/surgical team have linked, but
separate responsibilities. The potential
for human error is such that patient
checking must be a shared responsibility
that can never be delegated to a single
person” (Digger 2005, pg 5).
Pre-operative checklist
 the Patient Agreement to Investigation/Treatment form
is completed and signed.
 side and site of the operation is marked and this is
documented.
 the patient should be starved as per the trust preoperative guidelines and the times of the last food/fluids
noted on the checklist.
 any jewellery needs to be removed to prevent possible
burns from the diathermy or loss into an open wound.
(Digger 2005)
The ward staff must take all the patients medical records
and documents to the anaesthetic room in order for
theatre staff to correctly check the patient’s details.
Justine Barry 2008
The immediate postoperative care is as critical as the intra-operative care
and the child should be taken to a recovery area with trained staff (NDA 1998)
•
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The recovery nurse will obtain a full account of:
the operation that has been performed
instructions from the anaesthetist with regards to positioning of the patient, O2 therapy, IV fluids and pain
management.
Instructions from the surgeon about drains, packs, catheters and recommencement of oral feeding.
Children are observed on a 1:1 nurse to patient ratio and are continuously monitored for oxygen
saturation (Sa02), temperature, blood pressure (BP), colour, respirations, and consciousness . All vital
signs are recorded at five minute intervals to detect any signs of deterioration, distress or pain. Children
are nursed on a tilting trolley to protect the child’s airways should they vomit.
Oxygen is given initially to post-operative patients on reversal of anaesthesia to
encourage the transport of anaesthetic gases across the alveolar/capillary membrane
in the lungs and out of the body. Supplemental oxygen is often required in higher
concentrations because of the increase in the metabolic rate caused by surgery, since
it results in physiological stress and trauma (Hughes 2004).
This is essential in order to gain and relay accurate
information to ward staff, which will facilitate
smooth and on going transition of care. (CMMC
2004)
Justine Barry 2008
Why not look at effects
Of post-operative
Complications PONV
And Hyperthermia?
D
H ISC
ER
E
By Justine Barry 3rd year student (October 2008)
Please return this CD for the next person to
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Thank you.
Justine Barry 2008
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London.
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https://healthlibrary.epnet.com Spinal and Epidural Anaesthesia by Rosalyn Carson-DeWitt, MD
http://www.nwfsc.noaa.gov
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