4. Flashcards
a) List the implications for the patient of an inadvertent wrong-sided peripheral nerve block. (25%)
b) Summarise the recommendations of the ‘Stop Before You Block’ campaign and list factors that have
been identified as contributing to the performance of a wrong-sided block. (45%)
c) Define the term ‘never event’ as described by the National Patient Safety Agency and list three never
events of relevance to anaesthetic or intensive care practice. (30%
a) Which factors are most likely to
lead to an adverse airway event
when using a supraglottic airway
device (SAD)? (30%)
Patient factors:
> Obesity.
> Known/predicted difficult airway.
> Irritable airway: asthma, recent chest infection.
> Obstructive sleep apnoea.
> Aspiration risk: obesity, reflux, hiatus hernia, raised abdominal pressure,
pregnancy, drugs or conditions (recent trauma, recent pancreatitis,
pain, ileus, bowel obstruction, diabetes mellitus, chronic kidney disease)
affecting gastric emptying.
Surgical factors:
> Urgent surgery, inadequate fasting time.
> Lithotomy, prone, semi-prone or Trendelenberg positioning.
> Prolonged surgery.
> Abdominal surgery.
> Laparoscopic surgery.
> Shared airway surgery.
Anaesthetic factors:
> Junior anaesthetists, inadequate training, poor supervision, poor
attention to detail, poor patient selection, poor judgment.
> Use of SAD to avoid intubating patients with known/predicted difficult
airway.
> Difficulty siting SAD, resulting in problems during maintenance or
emergence.
> Light anaesthesia.
> First-generation SAD use.
b) How would you recognise that
a patient has regurgitated and
aspirated gastric contents during
an anaesthetic administered via a
SAD? (30%)
A:
> Gastric contents visible in the oropharynx/tube of SAD.
B:
> Desaturation.
> Cyanosis.
> Bronchospasm.
> Increased airway pressures/reduced tidal volumes in ventilated patient.
> Abnormal auscultation.
C:
> Tachycardia.
c) How would you manage this
patient? (40%
This is an anaesthetic emergency. I would alert the theatre team, call for
help and adopt an ABC approach, assessing and managing the patient
simultaneously.
A:
> Head down tilt +/− lateral tilt.
> Remove SAD.
> Oropharyngeal suction.
B:
> 100% oxygen.
> RSI (with cricoid pressure and avoidance of stomach inflation).
> Ideally, tracheal suction prior to ventilation but oxygenation is paramount.
> Positive pressure ventilation with PEEP.
> Symptomatic treatment with bronchodilators if necessary.
C:
> Ensure cardiovascular stability; manage as appropriate.
Once the patient is stable:
> Early bronchoscopy if particulate matter has been aspirated.
> Decision to continue with surgery depends on circumstances.
> Extubation or ventilation on ICU: dependent on clinical condition.
> If extubated, extended recovery stay for observation of respiratory rate,
oxygen saturations, other signs of respiratory distress.
> CXR.
> Maintain a high index of suspicion for aspiration pneumonia and treat
early (antibiotics not routinely advocated).
> Discussion with patient and/or family followed up by written information
of what symptoms should prompt the patient to seek medical help.
a) Define the types of unintentional
awareness that may occur during
general anaesthesia. (20%)
Explicit awareness:
> May have spontaneous recall, or recall prompted by questioning.
> May occur with or without pain.
> May result in psychological harm, sleep disturbance, nightmares, anxiety
or even post-traumatic stress disorder (PTSD).
Implicit awareness:
> No conscious recall but may affect behaviour and performance in the
future
b) What factors may increase
the likelihood of intraoperative
awareness? (55%)
c) What monitoring techniques
can be employed to reduce the
risk of awareness during general
anaesthesia? (25%)
Clinical monitoring:
> Presence of the anaesthetist throughout the case.
> Eye position.
> Pupillary dilatation and reactivity to light.
> Sweating.
> Lacrimation.
> Tachypnoea.
> Movement.
> Retching on tube/LMA.
General monitoring:
> Full equipment checks and ongoing monitoring during anaesthesia
(pumps, anaesthetic machine, vaporisers).
> Heart rate, respiratory rate and tidal volume (if not paralysed), blood
pressure.
> End tidal anaesthetic gas (ETAG) monitoring.
> TIVA pump effect-site or plasma-site concentration.
> Train-of-four monitoring to ensure that neuromuscular blockade is
reversible before ending anaesthesia.
Specific depth of anaesthesia monitoring:
> Processed EEG monitors convert the frontal signal into a dimensionless
number, 1–100 (100 = fully awake). BIS (target 40–60 for absence of
postoperative recall), M-Entropy and Narcotrend.
> Other specific monitors use auditory evoked potentials as a measure of
depth of anaesthesia.
a) What factors predispose to
inadvertent intra-arterial (IA) drug
injection that could lead to severe
extremity injury? (35%)
Patient factors:
> Unconscious so unable to indicate pain on cannulation/injection.
> Hypotension or hypoxia, causing failure to recognise cannula as arterial.
> Anatomically anomalous artery accidentally cannulated, thoracic outlet
syndrome with loss of radial pulse on abduction or rotation of arm.
Staff factors:
> Poor training resulting in failure to differentiate between artery and vein.
> Failure to check which line is being accessed.
> Failure to label line as arterial.
Drug factors:
> Some drugs have greater potential for harm than others, e.g. vasoactive
drugs, hyperosmolar drugs.
b) Outline the possible
intravascular mechanisms of
injury. (15%)
> Arterial spasm resulting in distal ischaemia: secondary to the drug itself
or due to mediators released in response to drug.
Chemical arteritis: direct tissue damage causing endothelial damage.
Initiation of release of harmful endogenous substances, e.g.
thromboxane, which cause endothelial damage and activation of
platelets resulting in thrombosis.
Drug precipitation and crystal formation in distal microcirculation causing
ischaemia and thrombosis.
c) What are the acute clinical
features of inadvertent IA
injection? (20%)
> Failure of drug to have intended effect.
Pain at and distal to the injection site.
Pallor, cyanosis and coolness of limb, or redness and warmth.
Paraesthesia.
d) What is the early management
of an acute IA injection injury?
(30%)
> Stop injection.
ABC assessment of patient, to include intravenous access and
administration of drug by intended route if urgent.
Keep cannula in situ for consideration of IA sympatholysis (with,
for example, iloprost or local anaesthetic) but ensure no other use > Elevation of extremity to improve venous and lymphatic drainage.
Pain control.
Consideration of anticoagulation with heparin.
Documentation.
Explanation and apology to patient/patient’s family, followed up in writing.
Incident report.
Plastics referral.
Consideration of stellate ganglion/lower limb sympathetic blocks.
a) Which human factors contribute
to intravenous drug administration
errors in theatre-based
anaesthetic practice? (30%)
Lack of knowledge:
> Unfamiliarity with a particular drug, its route of administration etc.
Human cognition:
> Human memory – cannot be relied upon to remember all infusion
mixtures, dose variations etc.
> Difficulty with complex calculations, e.g. paediatrics, infusions.
> Lack of knowledge of certain unfamiliar drugs.
Distraction:
> Needing to address other tasks whilst also drawing up drugs, prescribing
drugs, calculating doses, giving drugs.
> High noise levels.
Stress and fatigue:
> Tiredness, e.g. due to night work.
> Non-work emotional issues causing reduced work performance.
Lack of teamwork:
> Lack of double checking of drugs.
> Failure to feel able to voice lack of knowledge about a particular drug and
its administration.
> Failure to implement a ‘no blame culture,’ lack of encouragement of
reporting and learning from errors.
> Poor communication, poor handover: failure of one member of a team
to give explicit instructions to another about the administration of a
particular drug or whether a drug has already been given.
Excessive physical demands:
> Excessive workload, e.g. high turnover list.
Physical environment:
> Cluttered workspace, low light levels.
> Drugs with similar packaging, changes in packaging without notice,
unclear or too small labelling and lettering size.
b) Outline the organisational
strategies that might minimise
intravenous drug administration
errors. (70%)
Processes:
> Standardisation of cross-checking, handover etc.
> Standardisation of infusion doses, diluents etc.
> Availability of reference databases for doses, calculations, diluents.
> Regulations regarding what is drawn up and by whom and at what stage
in the care of a patient.
> Avoidance of distraction during drug preparation.
> Checklist to ensure prescription chart checked before administration
of drugs by anaesthetist to avoid double-dosing or omitted doses.
> Investigation of possibility of pre-mixed infusions.
> Flushing all lines as standard before leaving theatre and recovery.
Physical environment:
> Standardisation of lay-out and contents of anaesthetic carts.
> Ensure intrathecal/epidural drugs kept separate from intravenous drugs.
> Removal of non-essential, rarely used drugs from cart which have high
injury risk if inadvertently given.
> Ensuring label availability at all times.
> Process for dealing with unused ampoules to prevent them from
being returned to incorrect box (e.g. second-person check or discard
altogether).
> Ensure adequate lighting levels.
> Sourcing of products with clear labelling, sufficiently large lettering etc.,
where possible.
Team working:
> Simulation sessions to highlight risks to all team members.
> Unusual drugs to be dealt with in the team briefing.
> Encouragement of working environment where any team member feels
able to voice concern.
> Inclusion of pharmacist in team: notification of team members about
changes in product appearance, education about new drugs for inclusion
in anaesthetic carts etc.
Management of error:
> Open incident reporting with no-blame culture, lead clinician who will
analyse factors contributing to error and be responsible for national
reporting. Morbidity and mortality meetings for education of all team
members about pitfalls that may lead to error.
> Communication of e.g. Safe Anaesthesia Liaison Group reports to all
team members to help everyone learn from errors that have occurred
nationally
a) List the factors that may have
contributed to an increase in the
prevalence of asthma in developed
countries in the last 20 years.
(5 marks)
> Better identification of cases, influenced by targets for asthma
management in primary care.
Hygiene hypothesis: cleaner environment associated with increased rates
of allergy-associated asthma.
Obesity: increases an individual’s risk due to altered airway mechanics
and chronic inflammatory state.
Urbanisation.
Asthma development following survival from premature birth.
Increased use of drugs such as beta-blockers, NSAIDs, aspirin.
b) What are the possible causes
of acute bronchospasm during
general anaesthesia in a patient
with mild asthma? (5 marks)
> Pre-existing upper respiratory tract infection, poor asthma control,
smoking.
Airway irritation: cold inspired gases, airway secretions, airway
suctioning, laryngoscopy, intubation, extubation, aspiration, carinal
stimulation or endobronchial intubation.
Drugs causing histamine release, muscarinic block or allergy.
Vagal stimulation: peritoneal or visceral stretch etc.
c) Outline the immediate
management of acute severe
bronchospasm in an intubated
patient during general
anaesthesia. (10 marks)
> Stop surgical/drug triggers where possible.
A: Ensure ETT patent, ensure position is correct (carinal or endobronchial
placement may have triggered bronchospasm), suction if required
(avoiding stimulation of trachea), 100% inspired oxygen.
B: Auscultate chest, confirm wheeze or even absence of breath sounds;
check SpO2, manually ventilate to assess compliance and apply higher,
sustained pressure for ventilation and longer expiratory flow time; and
increase inspired anaesthetic gas concentration.
C: Check heart rate and blood pressure, increase intravenous filling as
increasing intrathoracic pressure reduces venous return, reducing cardiac
output and causing a tamponade-type effect.
Drugs:
• Salbutamol MDI via airway adaptor on breathing circuit, 10 puffs.
• Salbutamol IV 100–300 mcg bolus in extremis/5–20 mcg/min ivi.
• Magnesium 1.2–2 g/20 min IV bolus.
• Adrenaline IV 0.2–1 mg bolus in extremis/1–20 mcg/min ivi.
• Hydrocortisone 200 mg IV.
Once acute situation has resolved, monitor response with arterial blood
gas, assess whether safe to proceed with case or whether to abandon,
to keep intubated and take to ICU or whether safe to wake the patient
up.
Incident reporting.
Consideration of need for referral for optimisation of asthma control.
Full explanation to patient and/or family, including a written explanation of
what has occurred.
a) What are the factors associated
with an increased risk of
accidental awareness under
general anaesthesia (AAGA)?
(14 marks)
The following is lifted straight from the executive summary of the NAP5
report:
Drug factors: NMBD, thiopentone, TIVA.
Patient factors: female gender, young adults, obesity, previous AAGA,
possibly difficult airway.
Surgical factors: obstetric, cardiac, thoracic, neurosurgical.
Organisational: emergencies, junior anaesthetists, out of hours
operating.
More detail can be added in after reading through the individual chapters,
but the majority of the marks could have been obtained by reading the
executive summary only.
Drug factors:
> TIVA results in a full range of human and equipment error issues: tissued
cannula, pump failure, failure to switch the pump on, pump wrongly
programmed.
> Neuromuscular blocking drug (NMBD): 97% of the episodes of
awareness reported to NAP5 included use of NMBD. Failure to reverse,
failure to monitor depth of block, human error causing syringe switches,
failure to label syringes properly, mixed up ampoules.
> Increased incidence of awareness associated with thiopentone use.
> RSI.
Patient factors:
> Female gender.
> Young adults.
> Difficult airway.
> Obesity: difficulties with drug dosing and increased risk of difficult airway.
> Previous awareness: possible genetic component.
> Sick, cardiovascularly compromised patients in whom lower doses of
anaesthetic agents were given.
Surgical factors:
> Obstetrics, especially emergency LSCS: anxiety, no pre-medication,
physiological changes of pregnancy mask awareness, NMBD used,
thiopentone commonly used, may underdose due to failure to take
account of body weight, rapid sequence induction, emergency
(increased risk of error), junior anaesthetist, out of hours, short period
between intubation and commencement of surgery, not giving adequate
time for drugs to work. Failed regional is a risk factor according to the
reports submitted.
> Cardiac: not many cases in NAP5, but previously high level of awareness
reported at start of cardiopulmonary bypass. May also relate to cardiac
anaesthesia technique (low hypnotic dose, high opioid dose). May be
less likely to report as patients are warned of waking in cardiac ICU with
tube still in situ, and older patients may possibly be more tolerant.
> Thoracics: NMBD usually used. Switching tubes (single lumen to double
lumen) and failing to maintain anaesthesia by volatile technique. Rigid
bronchoscopy – episodes of intense stimulation, intermittent interruption
to anaesthesia administration if volatile used, NMBD needed.
> Neurosurgical.
Organisational:
> Out of hours.
> Junior anaesthetist.
> Emergency surgery.
b) What monitoring devices can be
used to help reduce the incidence
of AAGA? (2 marks)
On this occasion, the College has asked specifically about monitoring
devices, so it is not relevant to include information about the presence of an
anaesthetist and observance of clinical signs.
General monitoring:
> Full equipment checks and ongoing monitoring during anaesthesia
(pumps, anaesthetic machine, vaporisers).
> Heart rate, respiratory rate and tidal volume (if not paralysed), blood
pressure.
> ETAG monitoring.
> TIVA pump effect-site or plasma-site concentration.
> Train-of-four monitoring to ensure patient is reversible before ending
anaesthesia.
Specific depth of anaesthesia monitoring:
> Processed EEG monitors convert the frontal signal into a dimensionless
number, 1–100 (100 = fully awake). BIS (target 40–60), M-Entropy and
Narcotrend.
> Other specific monitors use auditory evoked potentials as a measure of
depth of anaesthesia.
c) What are the possible
consequences to the patient of an
episode of AAGA? (4 marks)
> There may be immediate, delayed or no recall.
Experiences may be auditory or tactile; may include pain and awareness
of paralysis.
Response very varied: neutral feelings about experience to extreme
distress at the time and also subsequently in the form of post-traumatic
stress disorder with flashbacks, anxiety and depression, with impact on
personal, social and work life
May cause avoidance of all medical settings or specifically anaesthesia
and loss of trust of healthcare professionals.
No recall may still cause long-term problems with e.g. unexplained
anxiety due to implicit memory.
Patients tend to benefit from explanation and cognitive behavioural
therapy
A 60-year-old man is having an elective knee arthroscopy and has just aspirated a significant amount
of gastric fluid during anaesthesia. He has a supraglottic airway device in place and is breathing
spontaneously. His inspired oxygen fraction is 1.0 and the pulse oximeter shows an oxygen saturation of
91%.
a) Describe your immediate management of this patient. (4 marks)
There are only 4 points available for this answer and it asks for ‘immediate’
management only.
This is an anaesthetic emergency. I would alert the theatre team, call for
help and adopt an ABC approach, assessing and managing the patient
simultaneously.
A:
> Head down tilt +/− lateral tilt.
> Remove SAD.
> Oropharyngeal suction.
B:
> 100% oxygen.
> RSI (with cricoid pressure and avoidance of stomach inflation).
> Ideally, tracheal suction prior to ventilation but oxygenation is paramount.
> Positive pressure ventilation with PEEP.
> Symptomatic treatment with bronchodilators if necessary.
C:
> Ensure cardiovascular stability; manage as appropriate.
b) List the respiratory
complications he could develop in
the next 48 hours. (2 marks)
> Sustained hypoxia.
Bronchospasm.
Pneumonitis.
Complications of barotrauma, including pneumothorax due to ongoing
high airway pressures.
Lobar collapse.
Pulmonary infection.
ARDS
c) What are the possible
preoperative risk factors for
regurgitation and aspiration of
gastric contents in this case?
(6 marks)
From the long list of risk factors for aspiration with an SAD, I have extracted
the ones that may relate to a 60-year-old man having an elective knee
arthroscopy.
> Obesity.
> Failure of the lower oesophageal sphincter: reflux, heartburn, hiatus hernia,
previous upper gastrointestinal surgery, gastro-oesophageal disease
> Drugs or conditions (recent opioid-based analgesia, recent pancreatitis,
diabetes mellitus, chronic kidney disease) affecting gastric emptying.
> Failure to follow starvation advice preoperatively.
