Anaesthetics II Flashcards
A 70-year-old male is four hours post transurethral resection of the prostate (TURP) performed under a spinal anaesthetic.
After three hours on the ward he has become increasingly short of breath and is now tachycardic and hypotensive. His urinary catheter bag, last emptied in recovery, contains 200 ml of ‘mildly’ blood stained urine.
Which of the following statements is the most likely to be correct?
(Please select 1 option)
He has TURP syndrome and should be given furosemide
He is probably having a myocardial infarct so senior help is required
He should be fluid resuscitated with group specific blood
His catheter may be blocked with blood clot CorrectCorrect
The spinal anaesthetic is high and he needs fluid resuscitation
The initial management of this patient involves giving him high flow oxygen, attaching monitoring equipment (pulse oximeter, ECG and blood pressure), taking a brief history and examining the patient.
TURP syndrome is caused by the absorption of irrigation fluid (usually 1.5% glycine) through open prostatic vessels.
Symptoms are caused by:
Intravascular volume overload
Dilutional hyponatraemia, and
Intracellular oedema.
Features may occur during surgery or post-operatively and include:
Bradycardia Hypertension (or hypotension - heart failure) Angina Dyspnoea Visual and mental changes Convulsions, and Coma. If on clinical examination he is fluid overloaded and has a low serum sodium then TURP syndrome is likely, which will allow prompt treatment with a diuretic.
On the basis of the information provided one cannot jump to the conclusion that he has TURP syndrome and give fruosemide without reason as this could make the hypotension worse. Hyponatraemia (
Regarding postoperative complications, which of the following is correct?
A sore throat following major surgery is normally due to gastrointestinal reflux Atelectasis is unusual in the post-operative period Oxygen therapy should be limited due to the risk of free radial damage Respiratory depression post-operatively may be due to intraoperative opioids Swinging pyrexia and bradycardia should alert the possibility ofpulmonary embolus (PE)
It is not correct that a sore throat following major surgery is normally due to gastrointestinal reflux. It is normally due to tracheal intubation intra-operatively.
Atelectasis is not unusual, due to both surgical factors (i.e. abdominal pain) and anaesthetic factors (i.e. intubation and ventilation).
It is not true that oxygen therapy should be limited due to the risk of free radial damage. Whilst there are theoretical concerns about free radial damage, ensuring adequate patient oxygenation is the main aim.
It is true that respiratory depression post-operatively may be due to intraoperative opioids. Morphine can take up to 40 minutes to have its maximal effect.
PE can often be confused with a chest infection as both can feature pyrexia.
Regarding peri-operative management which of the following is correct?
Following abdominal surgery, regular deep breathing and a sufficient cough does not affect the incidence of chest infections Low molecular weight heparin post-operatively excludes pulmonary emboli (PE) as a cause of chest pain Nil by mouth includes oral medications Patients should generally be encouraged to mobilise early in the post-operative period Post-operative opiates reduce physiological stress and improve outcomes
Post-operative atelectasis is common and can be improved by physiotherapy and breathing exercises.
Low molecular weight heparin (LMWH) will reduce the incidence of PE and deep vein thrombosis (DVT) but not remove all risk.
Except when a patient is vomiting, has an ileus, or has a nasogastric tube, oral medications can usually be continued.
Early mobilisation reduces the risk of DVT and PE.
Opiates cause respiratory depression and may delay mobilisation.
postop thrombocytopaenia
Post-operative bleeding may be surgical or coagulation related.
Liaise closely with cardiology; drug-eluting stents can re-stenose if clopidogrel is not continued.
Liaise closely with cardiology, metallic valves often need continuous heparin infusions to prevent thrombotic events and valve damage.
The risk of gastrointestinal haemorrhage increases when these are combined.
Heparin induced thrombocytopenia (HIT) is well described in the literature.
Which one of the following features is characteristic of septic shock?
(Please select 1 option)
Decreased blood pressure, increased systemic vascular resistance
Decreased peripheral vascular resistance
Fall in blood pressure, rise in JVP and pulsus paradoxus
Increased blood pressure and increased peripheral vascular resistance
Increased pulmonary vascular resistance
Decreased peripheral vascular resistance
Septic shock is associated with sepsis or septicaemia, usually by Gram negative (endotoxic shock) bacteria, but also Gram positive bacteria, or rarely fungi.
It is frequently associated with abdominal and pelvic infection complicating trauma or surgery.
In early septic shock, the pre-load and after-load are decreased, and the myocardial contractility is increased. In late septic shock, the pre-load and after-load are increased and the myocardial contractility is decreased.
Due to endotoxin production in septic shock there is a reduction in peripheral vascular resistance which leads to vasodilatation.
Regarding burns in children
Burnt children lose heat rapidly and should be covered unless being examined.
Assessment of the depth and surface area are important components of the secondary survey and additional fluid replacement is calculated according to the following formula:
Additional fluid = % burn x weight (kg) x 4.
Partial thickness burn may extend to the dermis and full thickness beyond the dermis into deeper structures.
Smoke inhalation is the usual early cause of death and inhalational injury should be suspected if carbonaceous sputum is present or if there are deposits around the mouth and nose.
Which of the following does the diagnosis of brain stem death require?
Brain stem death (BSD) is confirmed by demonstrating the absence of brain stem reflexes, and is characterised by profound coma. An independent existence is impossible after BSD.
Before the tests can be performed, several preconditions must be met unequivocally:
the presence of apnoeic coma
a defined cause of severe and irreversible brain damage and
the exclusion of potentially reversible conditions which can mimic BSD (hypothermia can mimic BSD, so the core temperature must be above 35°C).
The tests must be performed by two doctors and then repeated following an interval determined by the clinical condition of the patient (not 24 hours apart).
The confirmatory tests include:
fixed unresponsive pupils with absence of both the direct and consensual light reflexes (the pupils do not have to be dilated and pupil size is not a factor)
absent corneal reflexes
absent oculocephalic reflexes, with no doll’s eye movements (i.e. the eyes do not move on rotating the head from side to side)
absent vestibulo-ocular reflexes
absent motor activity after painful stimulation
absent gag reflex
absence of spontaneous respiration.
Spinal reflexes are often retained in BSD, and this is due to intact neural arcs acting independently of central control. Therefore, the absence of spinal reflexes is not required to diagnose BSD.
Hospital acquired infection
Person to person contact is a very common cause of infection spread in hospitals, which explains why scrupulous hygiene when moving between patients on an ITU is essential.
If an item of equipment is contaminated with bacteria, the number of bacteria will usually remain constant, or decline, if the item is dry. If the item is wet, some bacteria, e.g. Pseudomonas, may multiply.
Aerosols caused by air-conditioning units are notorious for spreading Gram-negative bacteria, e.g. coliforms and Legionella.
Sterilisation renders an article sterile and infection free and the process includes the destruction of bacterial spores.
Theatre air systems generate a positive pressure compared to the surroundings (not subatmospheric). The positive pressure air is moved away from the patient and filtered, so that airborne infections are prevented from reaching the patient. The laminar flow used in orthopaedic theatre is the logical progression of this concept.
Which of the following is true regarding paediatric abdominal trauma?
A double contrast CT scan of the abdomen (using intravenous and intragastric contrast) is the radiological investigation of choice in children (not a plain CT), but should only be performed if the patients are cardiovascularly stable.
Rectal examinations should only be performed on children by the operating surgeon and even then it should only be done if the results of the examination will alter the management.
A diagnostic peritoneal lavage (DPL) should rarely be used in children, as the presence of intraperitoneal blood per se is not necessarily an indication for laparotomy. A DPL is considered positive if
the red cell count is over 100,000/mm3
the white cell count over 500/mm3, or
enteric contents or bacteria are seen.
Fluid resuscitation is based on boluses of 20 ml/kg of crystalloid, not 4.5% albumin.
Which of the following is true regarding preoperative starvation?
Nil by mouth (NBM) policies may vary slightly between clinicians and hospitals. However, safe practice is no solid food for six hours prior to a general anaesthetic or procedures involving sedation (not four hours).
Chewing bubble gum or eating any type of confectionery should be avoided as this promotes gastric acid secretion and increases the gastric volume.
All types of milk are classed as solid food and so the same six hour rule should be applied (not two hours), although three hours is acceptable for breast milk.
Water or clear fluids can be consumed up to two hours pre-operatively (not one hour).
Patients having regional or local anaesthetic procedures should follow the same NBM policy as those scheduled for a general anaesthetic.
Which of the following is true regarding intra-arterial blood pressure monitoring?
(Please select 1 option)
Air bubbles cause a hyper-resonant trace
Fluid-filled tubing conducts the intravascular pressure wave from the catheter tip to the transducer
Non-pressurised fluid is infused through the catheter
Shortening the lengths of tubing has a dampening effect
The transducer should be at the same height as the catheter insertion point
Invasive arterial pressure monitoring provides beat-to-beat information with sustained accuracy.
The intravascular pressure wave is conducted from the catheter tip, situated in the arterial lumen, to the transducer along fluid-filled tubing. Pressurised fluid is infused through the catheter continuously.
The transducer is usually a strain gauge variable resistor which is connected to an amplifier and oscilloscope. The transducer should be placed at the height of the left atrium at all times.
Air bubbles and long catheter tubing have the effect of dampening the trace (waveform appears rounded). Increased damping usually lowers the systolic pressure and elevates the diastolic pressure.
Which of the following is true regarding hypothermia?
(Please select 1 option)
Alcohol is a cause
Defined as a temperature of less than 32°C
Intramuscular morphine should be given if analgesia is required
May cause delta waves on the electrocardiogram
Warm air blankets are an example of active internal re-warming
Hypothermia is defined as a temperature of less than 35°C and, when severe, may cause J waves on the electrocardiogram (delta waves are seen in Wolff-Parkinson-White syndrome).
Alcohol intoxication is a common cause, due to vasodilatation.
Drugs should not be administered via the intra-muscular route because vasoconstriction produces variable absorption and effect.
Warm air blankets are an example of active external re-warming.
Which one of the following is a suitable antidote in the management of drug overdose or poisoning?
In the management of overdosage and poisoning specific antidotes exist for particular drugs.
N-acetylcysteine may be indicated in a paracetamol overdose, glucagon is given for an overdose of beta-blockers, and ethanol is given for methanol poisoning.
The antidote for iron poisoning is deferoxamine, which chelates iron.
Flumazenil is the antidote for benzodiazepine toxicity, whereas naloxone is the antidote for opiate toxicity.
Which of the following is true regarding the management of a pulmonary embolus?
An inferior vena cava filter is required in every case
Anticoagulation should initially be with warfarin
Low molecular weight heparins should be monitored using the activated partial thromboplastin time (APTT) IncorrectIncorrect answer selected
Subarachnoid haemorrhage is a contraindication to anticoagulation This is the correct answerThis is the correct answer
The aim of warfarin therapy is an International Normalised Ratio (INR) of 3 to 4
The most appropriate method of monitoring the anticoagulant effect of low molecular weight heparins is to measure anti-factor 10 activity.
Warfarin may be started on day one, but it often takes several days to achieve adequate anticoagulation levels (INR 2.0-3.0).
The insertion of inferior vena cava filters (for example, Greenfield filter), thrombolysis and surgical embolectomy may be necessary.
Contraindications to systemic anticoagulation for a pulmonary embolus include
Recent major haemorrhagic trauma
Recent central nervous system haemorrhage or infarct
An active gastrointestinal haemorrhage.
Which of the following is a clinical manifestation of a pulmonary embolus (PE) in childhood?
Bradycardia Chest pain CorrectCorrect Haematemesis Hypothermia Reduced central venous pressure
Chest pain
The clinical manifestations of a PE include:
Dyspnoea Tachypnoea Tachycardia (not bradycardia) Chest pain Cough Haemoptysis, and Fever. The central venous pressure is usually elevated.
Back pressure from raised right-sided pressures causes elevated JVP.
