Blood pressure, pulse rate, respiratory rate, temperature, and level of consciousness

• The modified early warning system (MEWS), recommended by the British Thoracic Society (BTS), assesses and classifies the seriousness of the condition of an acutely unwell person (based on their blood pressure, pulse, temperature, breathing rate, and level of consciousness) to determine their need for urgent medical care [British Thoracic Society, 2008].
• MEWS is based on evidence (from a prospective cohort study of 673 medical admissions) of the association between vital signs and level of consciousness, and the risk of death, risk of cardiac arrest, and need for treatment in a high dependency or intensive care unit [Subbe et al, 2001].
• The CRB-65 scoring system, recommended by BTS, assesses the risk of harm for people with community-acquired pneumonia based on the presence of: confusion (recent); respiratory rate of 30 breaths/min or greater; blood pressure (systolic 90 mmHg or less, or diastolic 60 mmHg or less); and age (65 years of age or older) [Lim et al, 2009].
• The CRB-65 assessment is based on evidence of the risk of death from a cohort study, that prospectively followed 1000 people who had been admitted to hospital with a primary diagnosis of community-acquired pneumonia [Lim et al, 2003].
• The SIGN and BTS guideline The management of asthma recommends assessing the risk of harm for people with acute asthma based on respiratory rate, blood pressure, pulse rate, and level of consciousness (as well as their peak expiratory flow rate, oxygen saturation, presence of central cyanosis and signs of exhaustion) [SIGN and BTS, 2009].
• This assessment is based on evidence from confidential enquires into over two hundred asthma deaths in the UK of the association between these clinical features and the risk of death in people presenting with acute severe asthma.
• CKS takes the view that the similarity of the recommended methods of assessing risk in widely differing conditions can be taken as evidence that these methods of assessment can reasonably be extrapolated to all people who are acutely ill, whatever the cause, and to people with breathlessness where the cause is unknown.

Oxygen saturation less than 92%

• The BTS guidelines for the management of community acquired pneumonia in adults: update 2009 recommend that pulse oximetry should be available to general practitioners to assess severity and oxygen requirement in people with community-acquired pneumonia and other acute respiratory illnesses [British Thoracic Society, 2009].
• The Scottish Intercollegiate Guidelines Network (SIGN) and BTS guideline on the management of asthma recommends that people with asthma and oxygen saturation of less than 92% should be admitted to hospital as they are at high risk of death [SIGN and BTS, 2009].

Central cyanosis

• Central cyanosis is reported to be present when the concentration of deoxygenated haemoglobin is more than 50 g/L. This corresponds to an arterial oxygen saturation of less than 90% in people who are not anaemic [Douglas and Bevan, 2009].
• The SIGN and BTS guideline The management of asthma recommends that people with asthma and oxygen saturation of less than 92% should be admitted to hospital as they are at high risk of death [SIGN and BTS, 2009].

Stridor

• Stridor is a sign of upper airway obstruction. It carries a high risk of death or serious morbidity. Experts recommend immediate admission [Zoorob and Campbell, 2003].

Peak expiratory flow rate (PEFR)

• The SIGN and BTS guideline The management of asthma recommend that people with asthma and PEFR less than 30% of predicted, have life-threatening asthma; and recommends emergency admission [SIGN and BTS, 2009].
• The guidelines also recommend that, for people with known asthma and PEFR less than 50% of predicted, the decision to admit should be based on their response to treatment and the risk of subsequent deterioration (based on their previous history).
• These recommendations are based on evidence from confidential enquires into over two hundred asthma deaths in the UK that identified clinical features associated with an increased risk of death.

Other indications for admission

• Suspected pulmonary embolism, pneumothorax, sudden-onset cardiac arrhythmia, or silent myocardial infarction are known to be associated with a high risk of death or serious morbidity. Experts recommend immediate admission [Zoorob and Campbell, 2003; Arrhythmia & Sudden Cardiac Death Subgroup, 2007].