Article Text

Download PDFPDF
Critical care in the emergency department: monitoring the critically ill patient
  1. F J Andrews1,
  2. J P Nolan2
  1. 1Departments of Intensive Care and Emergency Medicine, Prescot, Merseyside, L35 5DR, UK
  2. 2Department of Anaesthesia and Intensive Care Medicine, Royal United Hospital, Combe Park, Bath, BA1 3NG, UK
  1. Correspondence to:
 F J Andrews
 Departments of Intensive Care and Emergency Medicine, Whiston Hospital, Prescot, Merseyside, L35 5DR, UK;francis.andrews{at}


The aim of monitoring patients is to detect organ dysfunction and guide the restoration and maintenance of tissue oxygen delivery. Monitoring is a crucial part of the care of the critically ill patient in the emergency department as the physiological response to critical illness is linked strongly to outcome. As it is important to appreciate the limitations of monitoring systems and monitored data, and to understand that invasive monitoring may be hazardous, this review concentrates on the techniques used to monitor critically ill patients in the emergency department. End tidal carbon dioxide monitoring, pulse oximetry, arterial blood pressure monitoring, central venous pressure monitoring, continuous central venous oxygenation saturation monitoring, temperature monitoring, and urine output are discussed. Practitioners should be familiar with the physiology and technology underlying these monitoring techniques and be aware of the pitfalls in interpretation of monitored data.

  • CVP, central venous pressure
  • ETCO2, end tidal carbon dioxide
  • MAP, mean arterial pressure
  • NICE, National Institute of Clinical Excellence
  • PAC, pulmonary artery catheter
  • PaO2, arterial oxygen partial pressure
  • PaCO2, arterial carbon dioxide partial pressure
  • PEEP, positive end-expiratory pressure
  • SaO2, arterial oxygen saturation
  • ScvO2, central venous oxygen saturation
  • SpO2, oxygen saturation at the peak of blood pulsation
  • SvO2, mixed venous oxygen saturation
  • SVR, systemic vascular resistance
  • monitoring
  • emergency medicine
  • critical illness

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Funding: none

  • Competing interests: none declared