Acute and Critical Care Medicine at a Glance

Richard M. Leach

• Publisher: Wiley-Blackwell
• Year: 2010
• Print ISBN: 9781405161398
• eBook ISBN: 9781444327229
• Edition: 2
• Topic: Medicine
• Subtopic: Internal Medicine & Diagnosis

The at a Glance series is popular among medical students and junior doctors for its concise and simple approach and excellent illustrations.

Each bite-sized chapter is covered in a double-page spread with colour summary diagrams on the left page and explanatory text on the right. Covering a wide range of topics, books in the at a Glance series are ideal as introductory subject texts or for revision purposes, and are useful throughout medical school and beyond.

Everything you need to know about Acute and Critical Care Medicine... at a Glance!

Following the familiar, easy-to-use at a Glance format, and now in full-colour, Acute and Critical Care Medicine at a Glance is an accessible introduction and revision text for medical students. Fully revised and updated to reflect changes to the content and assessment methods used by medical schools, this at a Glance provides a user-friendly overview of Acute and Critical Care Medicine to encapsulate all that the student needs to know.

This new edition of Acute and Critical Care Medicine at a Glance:

• Provides a brief and straightforward, yet rapid, introduction to care of the critically ill that can be easily assimilated prior to starting a new job or clinical attachment
• Encompasses the clinical, diagnostic and therapeutic skills required to manage acutely ill patients in a variety of settings
• Includes assessment of the acutely unwell patient, monitoring, emergency resuscitation, oxygenation, circulatory support, methods of ventilation and management of a wide variety of medical and surgical emergencies
• Includes new chapters on fluid management, oxygenation, non-invasive ventilation, recognition of the seriously ill patient and hospital-acquired infections

This book is an invaluable resource for all undergraduates in medicine, as well as clinical medical students, junior doctors, nurses caring for acutely-ill patients and paramedics.

Pre-publication reviews:

"The material forms an excellent basis for junior doctors in critical care and anaesthesia to get a good grounding in the subject, without appearing too scary."
– Senior House Officer

"The system-based approach...provides excellent reference material when studying a particular subject, allowing the reader to easily delve into the book when necessary, without having to read from cover-to-cover. It is an excellent revision aid.... Much time has gone into eliminating superfluous data so maximal essential information can be conveyed quickly."
– UCL student

1 Recognizing the unwell patient

In the acutely unwell patient, assessment of deranged physiology and immediate resuscitation precedes diagnostic considerations because incomplete history, cursory examination and limited investigation often preclude classification by primary organ dysfunction. It is this initial diagnostic uncertainty and the need for immediate physiological support that defines acute and critical care medicine.

Recognizing the Acutely Unwell Patient

Early recognition that a patient’s condition is deteriorating is essential and should initiate immediate action to correct abnormal physiology and prevent vital organ damage (e.g. brain, kidneys). Clinical severity may be obvious from the end of the bed: as in sudden, catastrophic events (e.g. pulmonary embolism); presentation with established severe illness (e.g. emergency room); or in advanced, previously unrecognized, deterioration on the ward. In these cases, organ damage may have already occurred but immediate action prevents further injury. It is failure to recognize progressive deterioration on the ward, usually manifest as worsening physiological variables, and initiate preventative action, that is a common and unacceptable cause of morbidity and mortality.

Identification of ‘at risk’ patients (e.g. sepsis, postoperative) allows complications to be anticipated and prevented. ‘At-risk’ patients must be monitored, deterioration recognized and appropriate action initiated. Simple physiological parameters including temperature, blood pressure (BP), heart rate, respiratory rate, urine output and conscious level correlate with mortality. One, two or three abnormalities correlate with 30-day mortalities of 4.4%, 9.2% and 21.3% respectively. Early warning scoring systems based on these parameters (Fig. a) promote early detection and trigger interventions aimed at preventing unnecessary cardiac arrests and critical care admissions.

Assessment of the Acutely Ill Patient

A normal response to the question ‘Are you alright?’ indicates that a patient’s airway is patent and that they are breathing, conscious and orientated. No response (e.g. coma) or difficulty responding (e.g. breathlessness) suggests serious illness. Immediate assessment and management of these acutely ill patients is summarized in Fig. (b). It aims to ensure patient safety and survival rather than establishing a diagnosis. Assessment starts with detection and simultaneous treatment of life-threatening emergencies. It uses the ABC system: A – Airway, B – Breathing, C – Circulation, in this order, as airways obstruction causes death faster than disordered breathing, which in turn causes death faster than circulatory collapse. Appropriate life-saving procedures or investigations are performed (e.g. airway clearance, tension pneumothorax decompression) during examination (i.e. before the next step). Simple monitors (e.g. saturation, BP) are used to assist assessment when safely possible.

Airway (Chapters 5, 13) Obstruction is a medical emergency and unless rapidly corrected leads to hypoxia, coma and death within minutes. Causes include aspiration (e.g. food, coins, teeth, vomit), laryngeal oedema (e.g. allergy, burns), bronchospasm and pharyngeal obstruction by the tongue when reduced tone causes it to fall backwards in obtunded patients.

• Complete obstruction is characterized by absent airflow (feel over the patient’s mouth), accessory muscle use, intercostal recession on inspiration, paradoxical abdominal movement and absent breath sounds on chest auscultation.

• Partial obstruction reduces airflow despite increased respiratory effort. Breathing is often noisy, with ‘stridor’ suggesting laryngeal and ‘snoring’ nasopharyngeal obstruction.

Simple measures correct most airways obstruction. Suction removes blood, vomit and foreign bodies. Pharyngeal obstruction by the tongue (i.e. during coma) can usually be prevented by chin lift manoeuvres or insertion of an oropharyngeal (Guedel) airway (Chapter 13). Occasionally endotracheal intubation or rarely emergency cricothyroidectomy may be required.

Breathing (Chapters 5, 13) The most useful early sign that breathing is compromised is a respiratory rate <8 or >20/minute, whereas central cyanosis is usually a late sign. Examine depth and pattern of breathing, accessory muscle use, abdominal breathing and chest wall expansion. Abnormal expansion, altered percussion note (e.g. hyper-resonance), airways noise (e.g. stridor) and breath sounds may determine the cause of underlying lung disease (Fig. c). Saturation (S_aO₂), measured by pulse oximetry, and inspired oxygen concentration (F_iO₂) should be recorded. Arterial blood gases (ABG) provide information about ventilation as well as oxygenation (i.e. S_aO₂ may be normal but P_aCO₂ high due to poor ventilation). The S_aO₂ should be >90% in all critically ill patients. Respiratory acidosis (pH < 7.3, P_aCO₂ > 6.7 kPa) or hypoxaemia despite high flow oxygen therapy (S_aO₂ < 90%, P_aO₂ < 8 kPa) requires urgent intervention. Treatment depends on cause (e.g. COPD) and is discussed in later chapters.

Circulation (Chapters 5, 13) Assessment includes central and peripheral pulses (i.e. rate, rhythm, equality), BP, peripheral perfusion (e.g. limb temperature), urine output and conscious level. Initially BP is maintained by compensatory mechanisms (e.g. increased peripheral resistance). Cardiac output (CO) has to fall by >20% (i.e. equivalent to 1 L of rapid blood loss) before BP falls. Thready, fast pulses indicate poor CO, whereas bounding pulses suggest sepsis. Capillary refill time is usually <2 seconds and prolongation suggests poor tissue perfusion. Metabolic acidosis (base excess >−4) and raised lactate (>2 mmol/L) on ABG indicate tissue hypoxia. Hypovolaemia should be considered the primary cause of shock, unless there is obvious heart failure (i.e. resuscitate hypotensive patients with cool peripheries and tachycardia with intravenous fluids (Chapters 8, 9)).

Disability Neurological status is rapidly determined by pupil examination and conscious level assessment using simple scales (Fig. a) or the Glasgow Coma Scale (Chapters 3, 53). Hypoglycaemia, ischemia and injury (e.g. unrecognized hip fracture) must be excluded in every patient.

Full Patient Assessment When stability has been achieved, and assistance summoned, a thorough history and examination is required. The patient’s notes, treatment, investigations and charts must be reviewed. Trends in physiological parameters are often more useful than isolated values. If the diagnosis has not been established arrange further investigations as appropriate. Document a clear management plan and communicate this to those involved.

Management of the acutely unwell patient frequently involves several teams (e.g. medicine, surgery, critical care) but should be a ‘seamless’ process in which co-operation, communication and patient interests are foremost. Treatment should occur in clinical areas where staffing and technical support are matched to patient needs.

2 Admission and ongoing management of
the acutely unwell patient

Organization

Acute and critical care wards provide monitoring and treatment for patients with potentially reversible, life-threatening conditions that is not available on general wards. Patients should be managed and moved between areas where staffing and technical support match their severity of illness and clinical needs. Five types of ward area are described: (a) level 3: intensive care units (ICU); (b) level 2: medical/surgical high dependency units (HDU), post-operative recovery areas, emergency resuscitation rooms; (c) level 1: acute admission wards, coronary care units; (d) general wards (e) self-care wards.

Acute and critical care medicine (ACCM) encompasses the initial resuscitation, monitoring, investigation and treatment of acutely unwell or critically ill patients in levels 1–3 wards. All these patients require a high degree of monitoring and nursing support. Level 3 patients often require mechanical ventilation or have multiorgan failure. Level 2 patients...

Table of contents

• Cover
• Dedication
• Title Page
• Copyright
• Contents
• Preface
• Acknowledgements
• Units, symbols and a bbreviations
• Part 1 - General
• Part 2 - Medical
• Part 3 - Surgical
• Part 4 - Self-assessment
• Appendices
• Index