Acute Medical Emergencies

The Practical Approach

• Publisher: BMJ Books
• Year: 2011
• ISBN:
  9781444320220
• Edition: 2
• Topic: Medicine
• Subtopic: Emergency Medicine & Critical Care

Acute Medical Emergencies is based on the popular Advanced Life Support Group course MedicALS (Medical Advanced Life Support) and is an invaluable resource for all doctors dealing with medical emergencies.

This comprehensive guide deals with the medical aspects of diagnosis and treatment of acute emergencies. Its structured approach teaches the novice how to assess and recognise a patient in an acute condition, and how to interpret vital symptoms such as breathlessness and chest or abdominal pain.

There are separate sections on interpretation of investigations, and procedures for managing the emergency. It covers procedures for acute emergencies occurring anywhere - on hospital wards or beyond. The clarity of the text, including simple line illustrations, ensure its tried and tested procedures provide clear, concise advice on recognition and management of medical emergencies.

PART I

INTRODUCTION

CHAPTER 1

INTRODUCTION

INTRODUCTION

After reading this chapter you will understand:

• the current problems in the assessment of acute medical emergencies
• the need for a structured approach to the medical patient.

THE PROBLEM

A medical emergency can arise in any patient, under a variety of circumstances, e.g.:

• previously fit
• acute on chronic illness
• post-surgical
• precipitating or modifying the response to trauma.

The acute problem can be directly or indirectly related to the presenting condition, an associated complication, any treatment and/or the result of inappropriate action.

Key point

Inappropriate action costs lives

Furthermore, with the increase in the elderly population there is a corresponding increase in the number and complexity of medical problems. The management of such patients is compromised by conflicting demands such as financial constraints, limited bed availability, workforce availability and increased medical specialisation.

For the last few years there has been an annual increase of emergency admissions in excess of 5%. These account for over 40% of all acute National Health Service beds. In the UK the mean hospital bed complement is 641, but only 186 are allocated for medical patients, with an average of 95% of these housing patients admitted as emergencies.

The common acute conditions can be broadly classified according to the body system affected (Table 1.1).

Table 1.1 Classification of medical emergencies

Type	%
Cardiac	29
Respiratory	26
Neurological	21
Gastrointestinal	13

This information may be broken down further to reveal the common reasons for admission:

• myocardial infarction
• Stroke
• cardiac failure
• acute exacerbation of asthma
• acute exacerbation of chronic obstructive pulmonary disease
• deliberate self-harm.

Despite the fact that these are common conditions, frequent management errors and inappropriate action result in preventable morbidity and mortality.

A recent risk management study examined the care of medical emergencies. One or more avoidable serious adverse clinical incidents were reported. Common mistakes are listed in the box below.

Common mistakes

Failure to recognise and treat serious infection

Error in investigating – acute headache

– acute breathlessness

– epilepsy

Misinterpretation of investigations

Inadequate assessment of abdominal symptoms

This was only a small study but of the 29 patients who died, 20 would have had a good chance of long-term survival with appropriate management. In addition, out of the 11 patients who survived, 3 were left with serious neurological defects, 3 had avoidable intestinal resection and 4 patients suffered unnecessarily prolonged hospital admission.

The overall problems were identified as follows:

• Medical emergencies were not assessed by sufficiently experienced staff.
• A second opinion was not obtained.
• Assessment was inadequately performed before discharge.
• X-rays were not discussed with radiologists.
• Protocols were not used for standard conditions.

Diagnostic errors were made in 80% of patients because of inadequate interpretation of the clinical picture and initial investigations. Errors in patient assessment are listed in the box below.

Errors in patient assessment

Available clinical evidence incorrectly interpreted

Failure to identify and focus on very sick patients

Investigations misread or ignored

Radiological evidence missed

Standard procedures not followed

Inadequate assessment and/or treatment

Discharge from hospital without proper assessment

Furthermore, the assessment of medical patients requiring intensive care was either incomplete, inappropriate or too late to prevent increased morbidity and mortality.

Therefore, there are problems in the fundamental areas of medical patient care, i.e. clinical examination, requesting and interpreting appropriate investigations and communication. However, probably most important of all is knowing when and who to ask for help. One answer to this important problem is to provide a structured approach to patient assessment that will facilitate problem identification and prioritise management.

All that is required to manage medical emergencies is the application of focused knowledge and basic skills. These will ensure prompt accurate assessment and improve patient outcome. Avoidable deaths are due to inappropriate management, indecision or delays in assessment and/or treatment. In the study the average time for initial review after admission is 30 minutes, with a further 130 minutes passing before definitive management occurs.

In the UK, numerous studies have shown that specialist care is better than that provided by a generalist; e.g. prompt review by a respiratory physician has been shown to reduce both morbidity and mortality from asthma. The mortality from gastrointestinal haemorrhage falls from 40% to approximately 5% if the management is provided by a specialist in gastroenterology. Further, supportive evidence has been provided by studies in the US, where mortality from myocardial infarction or unstable angina was greater in patients managed by generalists.

However there are insufficient numbers of ‘specialists’ to manage all of these conditions. Besides, patients with sudden deterioration in their condition often present as ‘undifferentiated medical emergencies’, without a clear ‘label’ identifying which particular specialist is required. Some will require review by a general physician, whilst others will be managed at least initially by colleagues in the rapidly expanding, exciting discipline of acute medicine.

Thus, physicians need to know how to manage medical emergencies. This course will teach a structured approach for assessment that will enable you to deliver safe, effective and appropriate care.

Traditional medical teaching dictates that a history should always be taken from the patient before the clinical examination. This will subsequently allow a diagnosis or differential diagnosis to be postulated and dictate the investigations required. Unfortunately this approach is not always possible; e.g. trying to obtain a history from a patient who presents with breathlessness may not only exacerbate the condition but also delay crucial therapy.

This course has been developed by observing how experienced physicians manage medical emergencies. The results have shown quite an interesting cultural shift. Most of us, as we approach the patient, quickly scan for any obvious physical signs, e.g. breathlessness, and then focus our attention on the symptoms until the diagnosis is identified. Only when the patient’s symptoms have been improved can a history be taken and the remainder of the examination performed. This process has been refined and formalised to produce a structured approach to patient assessment so that the most immediately life-threatening problems are identified early and treated promptly. Thus, this structured approach considers the conditions that are most likely to kill the patient.

All other problems will be identified subsequently as part of the overall classical approach to the medical patient, i.e. taking a comprehensive history and examining the patient fully. Being aware at all time that should the patient deteriorate a reassessment should start at the beginning.

The key principles of MedicALS are shown in the box.

Key principles of MedicALS

Do no further harm

Focused knowledge and basic skills are essential for doctors dealing with acute emergencies

A structured approach will identify key problems and prioritise management

Prompt accurate assessment and treatment improves patient outcome

SUMMARY

The number and complexity of acute medical emergencies are increasing along with the potential for medical mishaps. Typically these result from a failure to assess acutely ill patients, interpret relevant investigations and provide appropriate management. This manual, and the associated course, will equip you with a structured approach to deal with these patients.

CHAPTER 2

RECOGNITION OF THE MEDICAL EMERGENCY

OBJECTIVES

After reading this chapter you will be able to:

• understand the clinical features of potential respiratory, cardiac and neurological failure
• describe these clinical features and use them to form the basis of the primary assessment.

Irrespective of the underlying pathology, the acutely ill medical patient who dies does so from failures of the respiratory, circulatory or central neurological systems separately or in combination. It is of paramount importance that the physician can recognise potential failure of these systems, as early intervention will reduce morbidity and mortality. The ultimate failure, a cardiorespiratory arrest, can often be predicted in the hospital setting as it is generally preceded by a period of physiological deterioration.

This chapter will provide an overview of the clinical assessment of patients with potential respiratory, circulatory and neurological failure. The chapters in Part II will then use this format to develop an in-depth assessment that produces a structured approach to the patient with a medical emergency. An underlying principle of the assessment system described below is that it is physiologically based rather than using the more classical format of history taking, examination and investigation.

Time Out 2.1

Think about a patient you have treated recently who was critically ill, and reflect on the good and/or bad aspects of their treatment. List the staff involved and assessments that took place during the management of this patient.

Draw a timeline and place the information from your lists on the line. At the end of the line, write down the outcome of the episode.

RECOGNITION OF POTENTIAL RESPIRATORY FAILURE

This can be assessed by examining the respiratory rate, effort of respiration and effectiveness of ventilation, as well as the effects of respiratory inadequacy.

Respiratory rate

The normal adult respiratory rate is 14–20 breaths/min. Variation outside this range is an indication of potential respiratory failure. Tachypnoea (greater than 30 breaths/min at rest) generally indicates that increased ventilation is needed because of hypoxaemia associated with disease affecting the airway, breathing or circulation. It can also indicate compensatory hyperventilation due to a metabolic acidosis associated with a non-respiratory problem. Similarly, a respiratory rate of less than 10 breaths/min is an indication of respiratory fatigue or loss of central respiratory drive, both potentially requiring ventilatory support.

Effort of respiration

Assessment of effort gives an indication of how hard a patient is working to breathe. If the patient can count to 10 in one breath, there is usually no significant underlying respiratory problem. Features which suggest increased respiratory effort are tachypnoea, intercostal and subcostal recession and accessory muscle use.

Effectiveness of ventilation

Effectiveness of ventilation is assessed by measurement of chest expansion, percussion and auscultation. Chest expansion indicates the volume of air being moved during the respiratory cycle.

The presence or absence of breath sounds allows assessment of airflow to specific areas of both lung fields. Any asymmetry should be noted. Pathology is generally on the side of abnormal signs.

Any added sounds should be noted. Stridor is a loud inspiratory noise and is indicative of laryngeal/tracheal narrowing or obstruction. During auscultation you may hear wheezing and/or a prolonged expiratory phase due to lower airway narrowing.

Key point

A silent chest is an extremely worrying sign

Oxygen saturation

Pulse oximetry is used to measure the arterial oxygen saturation (SpO₂). It is inaccurate in the following circumstances:

• SpO₂ < 70%
• poor peripheral perfusion
• in the presence of methaemoglobin or carboxyhaemoglobin.

Effects of respiratory inadequacy on other organs

Heart rate

Hypoxaemia initially produces a tachycardia. These changes are non-specific as other causes such as anxiety, fever or shock may coexist. However, severe or prolonged hypoxaemia will eventually lead to a bradycardia – a preterminal sign.

Skin colour

Hypoxaemia, via catecholamine release, produces vasoconstriction and hence skin pallor. Decreased oxygen concentration will lead to cyanosis as haemoglobin becomes deoxygenated. Central cyanosis in acute respiratory disease is indicative of imminent respiratory arrest. In the anaemic patient, cyanosis may be difficult to detect despite profound hypoxaemia, because the reduced total amount of haemoglobin may mean there is not enough deoxygenated haemoglobin to produce the cyanotic colour.

Mental status

The hypoxaemic patient will initially appear agitated and eventually will become drowsy. Similar features will also occur with hypercapnoea; in this situation the patient will be vasodilated and have a flapping tremor (asterixis).

RECOGNITION OF POTENTIAL CIRCULATORY FAILURE

Acute circulatory failure can also be defined as shock. Although this has multiple causes, during the initial assessment the overriding priority is to identify shock, rather than find a specific cause.

Circulatory failure is assessed by examining the heart rate, effectiveness of circulation and the effects of shock on other organs.

Heart rate

This increases in the shocked patient due to catecholamine release, generally secondary to a decreased circulatory volume in an effort to increase cardiac output. There are many reasons why a normal adult may experience a tachycardia (pulse rate > 100/minute) and other signs should be sought to confirm the clinical suspicion of circulatory failure.

Be aware that certain drugs (e.g β blockers) can prevent a compensatory tachycardia and very fit patients, in whom a pulse rate of 100/minute may be twice their resting pulse rate.

Effectiveness of circulation

Blood pressure

Compensatory mechanisms will try to maintain blood pressure. Consequently, during the early stages of shock it may be normal or even elevated. For this reason, blood pressure should not be used as the sole indicator of circulatory status. Hypotension in circulatory failure...