Emergency Care Lecture: Emergency Resuscitation

Introduction

The cardiovascular and respiratory systems are two of the body's fundamental, life sustaining systems. As you saw in the previous chapter of this module, many patients admitted to emergency care settings in the United Kingdom (UK), and particularly those requiring immediate care, will have problems with their cardiovascular and / or respiratory function, and will require emergency resuscitation to sustain life. The rapid assessment and, subsequently, the management of a patient's cardiovascular and respiratory systems using resuscitation techniques is a crucial role for nurses working in emergency care settings.

This chapter introduces the principles and processes of emergency resuscitation. It begins with a brief discussion of the purpose of resuscitation in the emergency care setting, and a review of the anatomy and physiology of the cardiovascular and respiratory systems. It goes on to consider fluid resuscitation - including vascular access, aggressive fluid therapy and the administration of blood and blood products in the emergency care setting. The chapter then explains the emergency management of a patient with a compromised airway. Finally, the chapter discusses cardiopulmonary resuscitation (CPR), a fundamental skill for nurses in the emergency care setting, which uses a simple combination of cardiovascular and respiratory management techniques to sustain life whilst corrective interventions are implemented. The aim of this chapter is to prepare you to provide emergency resuscitation techniques as a nurse working in an emergency care setting.

What is resuscitation?

The term resuscitation is used to describe the processes involved in sustaining the life of an acutely unwell patient. Resuscitation relates in particular to the management of the function of the cardiovascular and respiratory systems, as these are two of the body's fundamental, life sustaining systems. Resuscitation involves the use of emergency actions to correct, in the short term, the physiological disorder/s affecting the patient. For example, cardiopulmonary resuscitation (CPR) - which you will study in detail in a later section of this chapter - uses a simple combination of cardiovascular and respiratory management techniques to sustain (over a period of minutes to, perhaps, hours) the life of a patient in cardiac and respiratory arrest. The fundamental goals of resuscitation are to sustain life (i.e. to prevent death), and to provide time for other interventions to correct the physiological disorder/s affecting the patient to be implemented and to take effect.

Anatomy and physiology of the respiratory and cardiovascular systems

In order to make sound decisions about the need for, and approaches to, resuscitation, it is crucial that nurses working in emergency care settings have a fundamental knowledge of the anatomy and physiology of the respiratory and cardiovascular systems. This section of the chapter will provide a very brief overview of the anatomy and physiology of these systems, highlighting key points relevant to emergency resuscitation. For more detailed information, you are encouraged to consult a quality nursing textbook.

The respiratory system is responsible for taking in oxygen, a gas which is fundamental in sustaining life. The cardiovascular system is responsible for moving oxygen, as well as waste products and other substances, around the body, for use or excretion. The cardiovascular system is comprised of two primary types of vessels:

1. Arteries - these transport oxygenated blood away from the heart.
2. Veins - these transport oxygenated blood towards the heart.

Blood - and, subsequently, oxygen - are transported through the cardiovascular system by the pumping action of the heart. This pumping action maintains a dynamic balance between cardiac output (via the arteries) and venous return (via the veins). In emergency situations where respiratory and / or cardiac function is impaired (e.g. because of lack of blood volume due to haemorrhage), or where the function of these systems ceases (i.e. in a situation known as an 'arrest'), this balance is disrupted. This results in a range of problems, the most significant of which is hypoxia, or a deficiency of oxygen in the tissues. Tissue hypoxia - and, in particular, cerebral hypoxia - can result in rapid organ failure; indeed, the human brain can only survive around 4 minutes without oxygen before irreversible damage occurs.

Many of the resuscitation strategies used in emergency care settings - including fluid replacement, the transfusion of blood and blood products, airway management and CPR, which you will study throughout the remainder of this chapter - are intended to provide a rapid response to hypoxia. In particular, these strategies aim to minimise cerebral hypoxia in the short-term.  These strategies provide time for other interventions to correct the physiological disorder/s affecting the patient to be implemented and to take effect.

Rationale for vascular access and fluid replacement

In emergency care settings in the UK, it is routine for patients who require immediate or urgent care - regardless of their presenting complaint - to have vascular access established. This is achieved via the insertion of a cannula - a hollow, fine-bore, flexible and sterile plastic tube - usually into the peripheral veins, most commonly in the hands and / or the arms. Vascular access allows for fluid replacement - that is, the intravenous administration of fluid solutions and blood / blood products. Fluid replacement aims to increase the volume of fluid in the cardiovascular system, thereby promoting organ perfusion and minimising hypoxia.

Vascular access

As described in the previous section of this chapter, vascular access is established via the insertion of a cannula into the peripheral veins of, most commonly, the hands and / or the arms. However, a variety of other vascular access sites may also be used; indeed, in emergency care settings it is not uncommon to see cannulas inserted into the veins of the legs, the feet and even the head / scalp. Occasionally, specialised cannulas will also be inserted into the large central veins (e.g. the subclavian, internal jugular and cephalic veins), the low-pressure arteries, and / or into the bone marrow (referred to as 'intraosseous insertion'). Also, some patients with chronic disease may present with semi-permanent catheters or implanted ports which allow for long-term therapy without the need for repeated vascular access (however, these must be used with caution). The exact site at which a cannula is inserted will depend on a number of factors - including the acuity of the patient's condition and the urgency of the care required, the condition of the patient's veins, and the characteristics of the solution/s to be administered to the patient.

Venous cannulation is the term used to describe the procedure of inserting a cannula into a vein, to access the cardiovascular system. It is important to highlight that undergraduate nursing students in the UK are not generally permitted to undertake venous cannulation; rather, this is a skill they may learn, should they wish to do so, by completing a postgraduate cannulation qualification. However, as an undergraduate student there are a number of important tasks related to venous cannulation with which you may assist. One of the most important of these is the selection of the correct size of cannula.

It is crucial that nurses in emergency care settings select the correct size of cannula. The size of cannula selected in a particular situation depends on factors such as the type and volume of fluid or blood product to be administered, the rate at which it must be administered, and the characteristics of the vein into which the cannula is to be inserted. In the UK, there are a number of options for cannula sizes: 24 gauge (yellow cannula), 22 gauge (blue cannula), 20 gauge (pink cannula), 18 gauge (green cannula), 16 gauge (grey cannula), and 14 gauge (orange cannula). It is important to remember that as the gauge of a cannula decreases, its bore - that is, its diameter and, subsequently, the volume of fluid it can deliver in a given period of time - increases. In most cases, 16 gauge (grey cannulas) and 14 gauge (orange cannulas) are used to rapidly administer high volumes of fluids and blood products in emergency situations.

Fluid replacement

As described earlier in this chapter, fluid replacement aims to increase the volume of fluid in the cardiovascular system, thereby promoting organ perfusion and minimising hypoxia. The type of fluid solution used, the rate at which it is administered, and the amount administered are determined by a number of factors. Most importantly, the emergency care team must take into account the patient's condition (particularly in terms of the functioning of their respiratory and cardiovascular systems), any current underlying pathophysiological conditions, and the extent of their fluid imbalance.

There are two main approaches to fluid replacement used in an emergency care setting:

1. Maintenance fluid replacement involves solution/s administered in low volumes over a long period of time (e.g. hours to days). This approach is used for patients who are physiologically stable but have little to no oral intake of fluid.
2. Aggressive fluid replacement involves solution/s administered in high volumes over a comparatively short period of time (e.g. minutes). This approach is used for patients who have significant volume depletion and may be very physiologically unstable.

It is aggressive fluid replacement that is used most often in emergency care settings. Algorithms for the administration of aggressive fluid therapy can be found in the National Institute of Health and Clinical Excellence's (NICE, 2013) Intravenous Fluid Therapy in Adults in Hospital (CG174) guideline, or the current equivalent. Nurses working in emergency care settings must also ensure they are familiar with their organisation's policies and procedures for the administration aggressive of fluid therapy, including local protocols, and that they work in a manner consistent with these at all times.

Generally, a patient requires aggressive fluid replacement when: they have a systolic blood pressure of <100mmHg, their heart rate is >90 beats per minute, their capillary refill time is >2 seconds or they have peripheral hypothermia, their respiratory rate is >20 breaths per minute, and / or their National Early Warning System (NEWS) score is ≥5. All these are objective signs of volume depletion and physiological instability. If any of these signs are evident, the Intravenous Fluid Therapy in Adults in Hospital (CG174) guideline recommends that nurses begin by identifying, and responding to, the cause of the fluid deficit (NICE, 2013). Concurrently, aggressive fluid replacement should be administered; ideally, a patient should be given a fluid bolus of 500 millilitres of a crystalloid substance, containing sodium in the range of 130-154mMol/L, over a period of fifteen minutes (NICE, 2013). Once this is done, the patient's clinical condition and, subsequently, their fluid needs are re-assessed; further fluid therapy, either aggressive or maintenance, may then be prescribed (NICE, 2013).

There are a variety of different types of intravenous fluids available for use in emergency care settings in the UK. These are organised into three categories:

1. Isotonic fluids are similar in composition to the body's own fluids. They act to directly increase the intravascular volume. 0.9% normal saline (NS) is an example of an isotonic solution used commonly in the emergency care setting.
2. Hypotonic fluids act to shift fluid into the intracellular space (i.e. from the vessels into the cells). They act to prevent cellular dehydration; however, in doing so they deplete circulatory volume. These are not often used in emergency care settings.
3. Hypertonic fluids act to shift fluid into the extravascular space (i.e. from the cells into the vessels). They are particularly useful for replacing serum electrolytes (discussed later in this chapter). 0. 5% dextrose in NS and 10% dextrose in NS are examples of hypertonic solution used commonly in the emergency care setting.

In addition, fluids may be categorised as:

• Crystalloid solutions, which act to increase the intravascular volume directly, through the actual volume of fluid administered. 0.9% NS, 5% dextrose and lactated Ringer's solution are all examples of crystalloid solutions used commonly in the emergency care setting. As highlighted above, it is crystalloid solutions which are most often used in aggressive fluid therapy in emergency care settings in the UK.
• Colloid solutions, which act to increase the intravascular volume indirectly, by moving fluid into the vascular space (via osmosis). Colloid solutions may be synthetic or natural. Fresh frozen plasma, albumin and packed red blood cells are examples of colloid solutions used commonly in the emergency care setting.

NOTE: Although the Intravenous Fluid Therapy in Adults in Hospital (CG174) guideline recommends the use of crystalloid solutions for aggressive fluid therapy in emergency care settings in the UK (NICE, 2013), many healthcare organisations use colloid solutions. Research evidence for the benefits and effectiveness of crystalloid versus colloid solutions is still unclear; indeed, their effects are largely comparable. It is essential that you are familiar with, and that you work within, your organisation's policies and procedures for the administration aggressive of fluid therapy, including in terms of the solutions administered.

As noted in an earlier section of this chapter, the fundamental aim of fluid therapy is to increase intravascular volume, promote organ perfusion and minimise hypoxia. However, aggressive fluid therapy may also be administered for other reasons - including to promote balance in the concentration of electrolytes in the body. Electrolytes are charged particles which are vital for the functioning of the organ systems at the cellular level; in particular, potassium electrolytes (K+) are fundamentally important for cardiac contractility. The administration of electrolyte-containing substances during aggressive fluid therapy is often used in emergency care settings to support the functioning of the organ systems.

As stated in the National Institute of Health and Clinical Excellence's (NICE, 2013: p. 5) Intravenous Fluid Therapy in Adults in Hospital (CG174) guideline, "errors in prescribing intravenous fluids and electrolytes are particularly likely in emergency departments". The mismanagement of fluid therapy can have significant negative effects on a patient, resulting in one or more of hypo- or hypervolaemia (related to intravascular volume), hypo- or hypernatraemia (related to serum sodium), hypo- or hyperkalaemia (related to serum potassium), and / or pulmonary or severe peripheral oedema. Disability or even death may result from such errors. Prior to administering any intravenous therapy, it is essential that nurses understand the fluid needs of the individual patient, the composition of the intravenous fluids being administered, and the rationale for this.

Administration of blood and blood products

In the emergency care setting, blood and blood products may be administered to patients with a variety of disease processes - including haemtologic disorders, the acute complications of cancer and haemorrhage. In emergency care settings in the UK, nurses will most often administer blood and blood products to respond to haemorrhage. Read the following about haemorrhage:

Guideline

Major haemorrhage can be defined as any of the following:

• Loss of more than the total blood volume within 24 hours (approximately 70mL/kg).
• Loss of ≥50% of the total blood volume in ≤3 hours.
• Bleeding in excess of 150mL per minute in adults.
• Blood loss which results in a systolic blood pressure of <90mmHg.
• Blood loss which results in a heart rate of >110 beats per minute in adults.

(NICE, 2015: p. 15).

When thinking about haemorrhage, it is important to not only consider external haemorrhages but also internal ones. Consider the following case study:

As with fluid therapy, described earlier in this chapter, the fundamental aim of the administration of blood in emergency care settings is to promote organ perfusion and minimise hypoxia. However, whilst fluids act to do this by increasing the intravascular volume, transfused blood does so by providing a greater number of binding sites for oxygen molecules entering the body via the respiratory system. Like blood, blood products may be administered to minimise hypoxia, however the administration of blood products is also done for a variety of other reasons - including to provide additional clotting factors, crucial in particular for patients experiencing severe haemorrhage.

There are many different types of blood products which may be administered to a patient in an emergency care setting, either alone or in combination. These blood products are often administered concurrently with the fluid therapies described earlier. Read the following:

• Red blood cells: these are often administered to patients with a frank haemorrhage. Prior to a transfusion of red blood cells, a cross-match will be performed to ensure that the patient's blood type is compatible with the donor type. Type O blood - a 'universal' type which is compatible with all other types - may be administered to patients where there is no time for a cross-match to be obtained.
• Platelets: these are cells which have a crucial role in blood clotting. A platelet transfusion may be given to patients with thrombocytopaenia and clinically-significant or severe bleeding, including bleeding within the central nervous system (NICE, 2015).
• Plasma: this is a nutrient-rich fluid which contains the blood cells in the cardiovascular system. A transfusion of fresh frozen plasma may be considered for patients with clinically-significant bleeding if they have abnormal coagulation test results (NICE, 2015)
• Cryoprecipitate: this is a substance within the blood that plays a key role in blood clotting. A transfusion of cryoprecipitate may be considered for patients with clinically-significant bleeding who have low levels of fibrinogen (NICE, 2015).
• Prothrombin complex concentrate: this is an artificial combination of blood clotting factors - including factors II, VII, IC, and X, as well as proteins C and S - prepared from fresh frozen plasma. A transfusion of prothrombin complex concentrate may be considered for patients with severe bleeding, and / or a head injury with a suspected intracerebral haemorrhage (NICE, 2015).

In situations of frank blood loss, such as haemorrhage, the body is depleted of all the blood components - blood cells, clotting factors, and other key substances. In these situations, whole blood replacement would be ideal - however, this is an expensive option, and due to chronic shortages of donated blood stocks in the UK whole blood is not often readily available. For this reason, blood components most suitable for a patient's particular needs are selected and administered.

Protocols for the administration of blood and blood products can be found in the National Institute of Health and Clinical Excellence's (NICE, 2013) Blood Transfusion (NG24) guideline, or the current equivalent. Nurses working in emergency care settings must also ensure they are familiar with their organisation's policies and procedures for the administration aggressive of fluid therapy, and that they work in a manner consistent with these at all times.

Airway management

So far, this chapter has considered strategies which may be used to manage the function of the cardiovascular system in emergency care settings. However, as described earlier in this chapter, the cardiovascular system works in tandem with the respiratory system to maintain life. For this reason, the management of the patient's respiratory system - specifically, by taking steps to ensure the patency of the airway - should be a priority for nurses in emergency care settings, including during resuscitation. 

Processes involved in the assessment of airway patency were described in the previous chapter of this module; you should revise this chapter now, if required. Where the airway of a patient in an emergency care setting is not patent, there are a number of ways the medical team may respond. Consider the following examples:

• The airway may be opened using a jaw-thrust manoeuver. This involves placing fingers and thumb on the patient's jaw, and tilting their head backwards. This has the effect of pulling the patient's soft tissues away from the back of their throat. However, this manoeuvre must be used cautiously if a patient has suspected spinal injuries, as it may result in spinal cord damage.
• The airway may be mechanically suctioned. This is a particularly important technique to remove secretions or a foreign body present in the airway. If the patient is conscious, they may be encouraged to cough deeply to achieve a similar effect.
• The airway may be opened via the insertion of an artificial airway and use of artificial ventilation. This is only appropriate if the patient is unconscious and medically sedated. There are a range of artificial airways which may be used; however, the most common in emergency care settings in the UK is an oropharyngeal airway (e.g. a Guedel airway). This is a rigid plastic tube which lies along the roof of the mouth and extends into the upper airway. An oxygen mask or other ventilation equipment can be attached to the external face of an oropharyngeal airway.

Cardiopulmonary resuscitation (CPR)

As described earlier in this section of the unit, cardiopulmonary resuscitation (CPR) is a fundamental skill for nurses in the emergency care setting. It involves the use of a simple combination of cardiovascular and respiratory management techniques to sustain life. You will receive CPR training as part of your undergraduate nursing degree, and you will be required to regularly update it throughout the time you practice as a registered nurse.

Remember: CPR progresses through a clearly-defined series of steps. Consider the following case study, which describes how each of these steps may be applied in nursing practice in an emergency care setting:

Conclusion

The cardiovascular and respiratory systems are two of the body's fundamental, life sustaining systems. Many patients in emergency care settings in the UK will present with problems with their cardiovascular and / or respiratory function. It is imperative that nurses are able to manage a patient's cardiovascular and respiratory function using emergency resuscitation techniques - and, so, to sustain their life whilst corrective interventions take place. This chapter has introduced the principles and processes of emergency resuscitation. It began with a brief discussion of the purpose of resuscitation in the emergency care setting, and a brief review of the anatomy and physiology of the cardiovascular and respiratory systems. It went on to consider fluid resuscitation - including vascular access, aggressive fluid therapy and the administration of blood and blood products in the emergency care setting. The chapter then provided an overview of the management of a patient with a compromised airway. Finally, it discussed cardiopulmonary resuscitation (CPR), a fundamental skill for nurses in the emergency care setting which uses a simple combination of cardiovascular and airway management techniques to sustain life. This chapter has prepared you to provide basic emergency resuscitation in your nursing role.

Reference list

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Kaufman, J.S. (2007). Nursing Assessment: Respiratory System. In S. Lewis, M.M. Heitkemper, S.R. Dirksen, P.G. O'Brien & L. Bucher (Eds.). Medical-Surgical Nursing: Assessment and Management of Clinical Problems - International Edition. (7th edn.): St Louis: Mosby-Elsevier.

NICE. (2013). Intravenous Fluid Therapy in Adults in Hospital. Retrieved from: https://www.nice.org.uk/Guidance/cg174

NICE. (2015). Blood Transfusion. Retrieved from: https://www.nice.org.uk/guidance/ng24

Resuscitation Council (UK). (2015a). Adult Advanced Life Support. Retrieved from: https://www.resus.org.uk/resuscitation-guidelines/adult-advanced-life-support/

Resuscitation Council (UK). (2015b). In-Hospital Resuscitation. Retrieved from: https://www.resus.org.uk/resuscitation-guidelines/in-hospital-resuscitation/

Resuscitation Council (UK). (2015b). Education and Implementation of Resuscitation. Retrieved from: https://www.resus.org.uk/resuscitation-guidelines/education-and-implementation-of-resuscitation/