Emergency medicine








After reading this chapter you should be able to assess diagnose and manage:




  • cardiac arrest



  • shock



  • anaphylaxis and acute upper airways obstruction



  • acute seizures



  • acute neurological emergencies


Children and young people frequently present to emergency departments with overwhelming and life-threatening acute conditions. Prompt assessment and management is crucial and requires the coordinated effort of skilled paediatric practitioners.


Basic life support


When any vulnerable children (premature infants or children with life threatening chronic illness) are discharged home; the parents should be taught about basic life support (BLS) techniques. The majority of paediatric cardiac arrests out of hospital or even within the hospital are due to respiratory failure, and therefore, early recognition and management of the airway and breathing are extremely important. The provision of basic life support, even by a single rescuer, can support the vital respiratory and circulatory systems until definitive help and expertise arrive.


Initial assessment of a collapsed or unconscious child


The steps in BLS have been designed to help teach the parents and carers about the early recognition of an unresponsive child and describe the sequence as:


Safe environment —ensuring that it is safe to approach the child and that there is no risk to the rescuer is crucial in the first instance. The child should be moved to a nearest place of safety such as being removed from a bath or leaving a building where there is fire.


Stimulate —stimulating the child or infant and looking for a response and, if there is no response, help should be summoned. Stimulation can be by shouting or tapping the shoulders. Tapping the feet of infants is appropriate but shaking the baby must not be undertaken.


Check airway and breathing —ensuring that the airway is open and patent and whether there is any breathing effort over a period of 10 seconds should next be undertaken. The airway can be opened by gently tilting the head backwards and the chin lifted to check the mouth for any apparent obstruction. Any obvious foreign bodies should be removed but the fingers should not be pushed deep in the mouth.


Circulation —the initial response includes five rescue breaths followed by 30 chest compressions. After the first cycle, the airway should be rechecked and two more breaths given before continuing the 2:30 cycle, although if there are two rescuers, the cycle should be 2:15. This should be continued until help arrives or child shows signs of life ,and once the child is breathing, they can then be placed in the recovery position to facilitate any fluids or vomitus draining easily out of the mouth and airway. The recovery position should be maintained and the child should not be allowed to accidentally roll back to their back.


Choking child —supporting a choking child with simple techniques could save them from going into cardiorespiratory arrest, although the technique used depends on whether there is breathing effort or the child is unresponsive.


When a cough and breathing effort are present, the child should be supported and encouraged to cough up and bring out the foreign object blocking the airway. If the cough or the breathing effort is poor or absent, an urgent response is required to help push out or cough up the foreign object. Depending upon the age of the child, different techniques could be used.


In the child who is less than 1 year old, chest thrusts are advisable as abdominal thrusts can cause damage to abdominal organs. The infant is held on the knee with the head down and five back blows are given to the thoracic area. The child is then turned to face the rescuer and, still on the knee with head down, five thrusts are given to the sternum. The cycle of five blows and five thrusts is continued until the foreign object is dislodged, but if the child is not responding then CPR should be commenced.


In the child above 1 year, it is safe and more useful to apply abdominal thrusts. The child is held in standing position and five firm back blows to the middle of their back are given followed by five abdominal thrusts which are sharp and aimed upwards towards diaphragm. As long as the child is responsive, this cycle can be continued until the foreign object is expelled. If the child becomes unresponsive, then CPR should be started and help sought.


Paediatric cardiac arrest


Primary respiratory failure is the most common cause of cardiac arrest in the paediatric population, whereas in adults cardiac causes are more common. However, the terminal event seen in children is mainly due to arrhythmias including ventricular fibrillation or pulseless ventricular tachycardia. The cardiorespiratory arrest in children has poor prognosis


Treatment and management


The APLS guidelines are taught to all trainees and can be summarised in the algorithm produced by the Resuscitation Council UK ( Figure 8.1 ).




Fig. 8.1


Paediatric Advanced Life Support algorithm

Reproduced with permission from the Resuscitation Council UK 2021


The key to management of cardiac arrest is its early recognition and call for help followed by systematic assessment (ABCDE). The immediate evaluation should be focused on identification and treatment of reversible causes along with assessment of cardiac rate and rhythm ( Table 8.1 ).



Table 8.1

Reversible causes of cardiac arrest










4 Hs 4 Ts
Hypoxia
Hypovolaemia
Hypothermia
Hyperkalaemia
Tension pneumothorax
Tamponade (cardiac)
Toxins
Thromboembolic phenomenon


The interventions are undertaken at every step of the ABCDE assessment, and each step of the management is not started until the preceding abnormality has been addressed, although there are some exceptions such as massive haemorrhage. In this situation, management of the circulatory problem is undertaken alongside assessment and management of airway and breathing.


Parental presence during cardiac resuscitation is known to be important and a dedicated member of the team should be allocated to support them and explain events taking place. The decision to stop resuscitation is made by the lead clinician when there is no spontaneous return of circulation after 30 minutes of effective resuscitation although children with primary hypothermia or those with poison ingestion may require longer periods of support.


Shock


Shock is an acute process in which the body is unable to deliver adequate oxygen to the vital organs and tissues to meet up their normal metabolic demands. As a result, the normal aerobic metabolism at cellular level is switched to anaerobic metabolism which is less effective. The poor tissue oxygenation will trigger multiple compensatory mechanisms in the body to preserve oxygenation to vital organs and this is manifested by poor capillary refill time seen especially in neonates and young children.


These compensatory mechanisms are initially very effective, hence the name compensated shock, during which time the blood pressure is maintained. The mortality rates in paediatric and neonatal shock, especially septic shock, are about 3% in healthy children and up to 9% in children with underlying chronic medical problems.


If the shock is not recognised and managed promptly, vital organs are further deprived of oxygen leading to metabolic and lactic acidosis. Early recognition and management of shock on presentation is vital to prevent the potentially rapid and irreversible or uncompensated shock that leads to multiorgan failure and death. Hypotension is a late sign of shock especially in the paediatric population.


Shock can be generally classified into five major types:




  • hypovolemic shock is the most common type of shock seen in the paediatric population globally and is frequently caused by fluid losses through diarrhoea, vomiting or haemorrhage



  • cardiogenic shock could be due to congenital or acquired heart diseases including myocarditis, cardiomyopathies and structural cardiac defects (pre- or postoperative)



  • distributive shock occurs due to loss of vasomotor tone as seen in anaphylaxis, burns, acute spinal cord or brainstem injuries and ingestion of certain drugs



  • obstructive shock occurs due to obstruction to normal cardiac output as seen with tension pneumothorax, cardiac tamponade or pulmonary embolism



  • septic shock is usually due to a combination of multiple types of shocks especially hypovolemic, distributive and cardiogenic. It could be caused by viral, bacterial or fungal infections and immunocompromised patients are at a particular risk of fulminant sepsis



Clinical manifestations


The clinical manifestations of any type of shock depend partly on the underlying aetiology, but if not treated then all types of shock follow the common pathway of multiorgan failure and death. Tachycardia is usually the early sign of all types of shock, followed by tachypnoea. Hypovolemia is a late sign especially in paediatric population and usually manifests during the advanced phase of uncompensated sepsis ( Table 8.2 ).



Table 8.2

Important signs of different types of shock.






















type of shock Signs
Hypovolaemic dry mucous membranes, poor skin turgor, cool peripheries, delayed capillary refill time, poor volume pulses
Cardiogenic tachypnoea, poor peripheral perfusion, gallop rhythm, hepatomegaly, reduced urine output, altering mental status
Distributive increased cardiac output but ineffective due to vascular dilatation
Obstructive poor peripheral pulses, low BP, tachypnoea, cool peripheries
Septic tachypnoea, bradypnea, pyrexia, hypothermia, low BP, poor peripheral pulses


Investigations


The laboratory investigations, imaging and other studies depend on the suspected underlying cause and type of shock.


The common investigations to be considered in a child presenting with shock include:




  • full blood count: may show leucocytosis or leucopenia, anaemia, thrombocytopenia



  • serum electrolytes and renal function



  • glucose



  • blood gas including lactate level



  • liver function tests and coagulation profile



  • C-reactive protein



  • blood and other tissue cultures



  • chest x-ray



  • ECG



Treatment and management


The key in management of any type of shock is its early recognition followed by stabilisation of airway, breathing and circulation and provision of specific therapy as indicated by the underlying aetiology. The guidelines and algorithms devised by the Advanced Paediatric and Neonatal Life Support groups should be followed.


Administration of IV sodium chloride 0.9% is usually required for volume expansion in the early phase of shock management, and a 20 ml/kg bolus is given and could be repeated up to 60–80 ml/kg. More cautious fluid resuscitation at 10 mls/kg per bolus may be more appropriate in some situations. Careful use in cardiogenic shock is required to avoid worsening of cardiac function. Refractory shock after 40–60 ml/kg fluid therapy will require the commencement of inotropes.


Relevant pharmacological agents used


Adrenaline increases cardiac contractility and heart rate although at high doses its vasoconstrictor effect may cause poor renal perfusion and arrhythmia.


Dopamine increases cardiac contractility and peripheral vasoconstriction may cause arrhythmias at higher doses.


Dobutamine is a cardio-selective inotrope that increases cardiac contractility and produces a peripheral vasodilator.


Antimicrobial therapy . Specific role in septic shock if the diagnosis of sepsis or septic shock is made then administration must occur within 1 hour of presentation.


Anaphylaxis


Anaphylaxis is a severe, life-threatening, generalised or systemic hypersensitivity. There is a range of symptoms and signs but anaphylaxis is likely when all of the following three criteria are met:




  • sudden onset and rapid progression of symptoms



  • life-threatening problems of the airway, breathing or circulation



  • skin or mucosal changes including flushing, urticaria and angioedema



Exposure to a known allergen for the patient helps support the diagnosis but it is important to remember that




  • skin or mucosal changes alone are not a sign of anaphylactic reaction



  • skin and mucosal changes can be subtle or absent in up to 20% of reactions



  • GI symptoms such as vomiting, abdominal pain and incontinence can also occur



Patients at risk of severe anaphylaxis include those with:




  • food allergy



  • history of asthma or current asthma exacerbation



  • delayed administration of adrenaline



  • previous biphasic or severe anaphylactic reactions



Biphasic anaphylaxis describes recurrence of symptoms that develop following the apparent resolution of the initial anaphylactic episode with no additional exposure to the trigger. They typically occur within 8 to 10 hours after resolution of the initial symptoms, although recurrences up to 72 hours later have been reported.


The child may feel and look unwell and occasionally describe a sense of ‘impending doom’. Other symptoms and signs will include:




  • airway swelling leading to difficulty in breathing and swallowing and a feeling that the throat is closing, hoarse voice, stridor



  • breathing problems include increased respiratory rate, wheeze, hypoxia leading to confusion



  • circulation compromise includes pale, clammy skin, tachycardia, low blood pressure leading to dizziness and collapse, decreased level of consciousness



  • skin and mucosal signs are often the first feature and present in about 80% of children. Patchy or generalised erythema, urticarial rash—often itchy, angioedema of eyelids, lips, mouth and throat



Investigations


Anaphylaxis is essentially a clinical diagnosis and laboratory tests are not commonly required. Mast cell tryptase will help confirm a diagnosis of anaphylactic reaction but measurement should not delay initial treatment of anaphylaxis.


Management of acute episode


The ABCDE approach as described in the APLS guidelines ( Figure 8.2 ) should be followed for all age groups




  • early call for help



  • follow Resus UK anaphylaxis algorithm



  • IM adrenaline—if indicated, administered as soon as anaphylaxis identified



  • investigation and follow up by an allergy specialist


Jun 18, 2022 | Posted by in PEDIATRICS | Comments Off on Emergency medicine
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