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As anaesthetists, we are trained to lead and guide resuscitation attempts and to become experts at dealing with the unexpected. Thankfully emergencies are not encountered regularly, so to manage them effectively we need to regularly refresh our knowledge. This chapter covers the recognition and management of the most commonly occurring emergency conditions and problems in anaesthesia, from anaphylaxis to paediatric resuscitation. It also includes some useful further reading options, with links to essential guidelines to help you prepare for when you need to act quickly.
Anaphylaxis
You are asked to anaesthetize a 56-year-old woman for a laparoscopic cholecystectomy. She is hypertensive, taking ramipril, and has mild asthma. There is no history of drug allergy, and she has undergone general anaesthesia previously without problems.
You pre-oxygenate, and then induce anaesthesia with fentanyl 100 mcg, propofol 180 mg, and atracurium 40 mg. Shortly after securing her airway with an oral endotracheal tube you administer co-amoxiclav 1.2 g.
Two minutes later the patient becomes blotchy and pale, and the NIBP machine does not read. The radial pulse is impalpable, and the ECG demonstrates a sinus tachycardia of 155 bpm. Simultaneously, the ventilator alarm signals high airway pressures, and you find she is difficult to hand ventilate. The pulse oximeter is no longer reading. The chest is quiet, with no obvious wheeze.
You suspect anaphylaxis, and in an attempt to immediately improve venous return to the heart, you raise her legs in the air. You administer 50 mcg aliquots of adrenaline to a total of 800 mcg, and a litre of crystalloid through a peripheral cannula.
Consider the following questions before turning to the discussion below:
1. What is the differential diagnosis?
2. What further clinical management does she require?
3. Would you continue with the case?
4. What blood tests and follow-up will she require? Whose responsibility is this to organize?
1. Differential diagnoses include:
2. A standard ABC approach is needed.
The early use of adrenaline is critical. Adrenaline stabilizes mast cells, in addition to its positive inotropy, vasopressor, and bronchodilator effects. An infusion may be required for ongoing maintenance of blood pressure.
Hydrocortisone 200 mg and chlorphenamine 10 mg are required, to help reduce the severity and duration of the reaction.
3. Would you continue with the case?
An elective case such as this should be postponed. For emergency work, the risks of postponing surgery must be weighed against the risk of continuing in the face of suspected anaphylaxis to an unknown agent.
4. What blood tests and follow-up will she require?
Serial mast cell tryptase measurements are required, looking for a peak rise. It is the anaesthetist’s responsibility to arrange follow-up.
The term ‘anaphylaxis’ describes the signs and symptoms resulting from widespread mast cell degranulation and histamine release. Degranulation can occur due to cross linking of specific IgE antibodies, or to non-specific, direct degranulation. The former is known as allergic anaphylaxis, the latter as non-allergic anaphylaxis (previously called ‘anaphylactoid’). The two cannot reliably be distinguished on clinical grounds alone. However, it is imperative for patient safety to establish the exact cause, in case a specific drug needs to be avoided in future by the patient.
Signs and symptoms of anaphylaxis include:
Major, unexplained hypotension
Tachycardia or bradycardia (the latter a more worrying feature associated with severe cases)
Major, unexplained respiratory compromise
Angioedema
Urticaria
Widespread rash
Severe itch.
Patients suffering any of these require referral to a specialist clinic for follow-up investigation. The referral paperwork is on the Association of Anaesthetists of Great Britain and Ireland (AAGBI) website. Serial mast cell tryptase levels should be taken immediately, at 1–2 hours, and at 24 hours. ‘Peak’ levels are at 1–2 hours, but may still be high at up to 6 hours from the event so can be taken up to this point. The 24-hour sample confirms a normal baseline tryptase; persistently raised levels may indicate the presence of a mastocytosis.
Neuromuscular blocking agents remain the most frequent cause of anaphylaxis, followed by antibiotics. However chlorhexidine, ubiquitous both in and out of theatres, has recently emerged as a frequent cause of anaphylaxis and often causes delayed and severe reactions.
Quoted incidence of proven anaphylaxis ranges from 1:1300 to 1:10 000, but incidence of adverse events meeting the AAGBI criteria for referral may be significantly higher. Under-reporting may reflect uncertainty about the referral pathway and blood tests required. To aid the anaesthetist, many hospitals have now developed ‘Suspected Anaesthetic Allergy Follow-Up Packs’, containing referral paperwork, blood bottles and template letters for the GP and patient. In areas where such packs have been introduced, the number and quality of referrals has increased, improving the likelihood of making a conclusive diagnosis at clinic.
Further reading
Management of can’t intubate can’t ventilate
A 20-year-old female is being anaesthetized for an appendicectomy. She is known to suffer from suxamethonium apnoea and so rapid sequence induction was performed using rocuronium 1.2 mg/kg. Her airway had not been predicted to be difficult; however, you are unable to intubate or ventilate her. You have tried an alternative blade, bougie and external laryngeal manipulation. The patient is becoming increasingly hypoxaemic.
What would be the next most appropriate step in managing this patient?
a) Perform an emergency needle cricothyroidotomy
b) Administer sugammadex in a dose of 16 mg/kg
c) Attempt intubation using a fibre-optic laryngoscope
d) Insert an oral airway and attempt facemask ventilation with 100% oxygen
e) Reduce cricoid pressure and reattempt intubation
Answer: d)
In this scenario the urgency of surgery is not immediate and the patient should be woken up.
This is an airway emergency as the patient is becoming increasingly hypoxaemic. The priority is to oxygenate the patient. This has already failed using facemask ventilation alone and so the next most appropriate step is to use an oral airway and attempt ventilation with 100% oxygen. If this fails the next step is to attempt insertion of a laryngeal mask airway and ventilate with 100% oxygen. If this fails a surgical cricothyroidotomy will be necessary to allow oxygenation of the patient. Fibre-optic intubation does not have a role in the scenario where a patient is becoming rapidly hypoxaemic.
Sugammadex is a selective relaxant binding agent which is given in a dose of 16 mg/kg to reverse the effects of a 1.2 mg/kg dose of rocuronium. A median time of 1.5 minutes to recovery of the T4/T1 ratio to 0.9 is expected. Sugammadex can be administered; however, the priority here is to oxygenate the patient first.
For further details regarding the management of the difficult airway, see Section 3, Chapter 33.
Further reading
Adaptation to basic life support in special circumstances
1. You receive a cardiac arrest call for the antenatal ward in the maternity unit. As you make your way there, you consider the following questions:
a) What are the adaptations to standard basic life support needed in a pregnant patient?
b) What are the possible causes of cardiac arrest specific to pregnancy?
The basic principles of basic and advanced life support are the same in a pregnant as a non-pregnant patient. Some additional points to remember:
Summon expert help immediately – senior obstetrician and, if fetus viable, neonatologist. Also request the anaesthetic consultant on call attends.
Aortocaval compression. If more than 20 weeks’ gestation then the pregnant uterus presses on the aorta and inferior vena cava, which can impede venous return to the heart, reducing cardiac output and, ultimately, uterine perfusion. It is essential to displace the uterus to the left to reduce aortocaval compression. If the patient is not on an operating table (i.e. a tilting table,) then the most effective way to do this is to manually displace the uterus.
Effective chest compressions are key to successful resuscitation; therefore, it is important that the patient is supported on a firm surface, e.g. a spinal board or operating table. Using soft pillows to tilt the patient is no longer acceptable (see point above regarding manual displacement of the uterus).
Increased risk of aspiration; consider early intubation.
If there is no return of spontaneous circulation within 4 minutes then the obstetrician should perform a perimortem section to deliver the baby by 5 minutes. This can take place anywhere and requires only a scalpel. The patient should be transferred to theatre following return of spontaneous circulation for completion of surgery.
Causes of cardiac arrest to consider in a pregnant patient include:
Pulmonary embolism
Sepsis
Hypertensive disorders of pregnancy
Haemorrhage
Placental abruption
Amniotic fluid embolism
Cardiac disease
How would you initially assess and manage this situation?
Shout for help. Try and get a quick history from the nursing staff/relatives.
Confirm cardiac arrest. Check for breathing, pulse and signs of life. Pulse palpation can be difficult in children, so if there is no breathing/signs of life after 10 seconds begin resuscitation. Ask a nurse to put out a cardiac arrest call.
Open the airway with head tilt, chin lift and give five rescue breaths. In children the cause of cardiac arrest is more commonly respiratory in origin rather than cardiac, so effective breaths are vital.
Begin cardiac compressions and use a rate of 15 compressions to 2 breaths. Cardiac compressions should be given at a rate of 100–120 compressions a minute. Compress the lower half of the sternum one finger breadth above the xiphisternum using 1–2 hands depending on the size of the child and the size of your hands. Aim to depress the chest by one-third.
If no one responds to your initial shout for help, perform one minute of CPR before leaving the patient to get help. However, if the arrest is sudden and witnessed the cause may be cardiac and help should be summoned before any resuscitation.
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