An Overview of Cough Cough Assessment Sally Cozens

An Overview of Cough & Cough Assessment Sally Cozens Respiratory Specialist Physiotherapy

Objectives • Revision of normal cough function • Why assess cough? • How to assess cough the components of cough • When to introduce airway clearance methods • Understanding Airway Clearance Techniques • An introduction to MI-E Specialists in Ventilation & Airway Clearance

Normal Physiological Cough Specialists in Ventilation & Airway Clearance

Normal Cough ‘‘Cough is a forced expulsive manoeuvre, usually against a closed glottis and which is associated with a characteristic sound. ’’ (BTS 2006) Coughing and support from the mucocilliary escalator protects the respiratory system by clearing it of irritants and secretions Specialists in Ventilation & Airway Clearance

Stages in a Normal Physiological Cough Irritation or Initiation Post Cough Inspiration / Recovery Expiratory Phase Inspiratory Phase Compressive Phase Specialists in Ventilation & Airway Clearance (Yanagihara et al. 1966)

Requirements For A Normal Cough Specialists in Ventilation & Airway Clearance

Glottis Arytenoid Cartilage Glottis Trachea Vocal Folds/ Cords Epiglottis Specialists in Ventilation & Airway Clearance

An Effective Cough Inspiratory Phase Glottis open, rapid Inhalation, 85 -95 % of TLC Compressive Phase Expiratory Phase Glottic closure, expiratory muscles contract, increase in intrthoracic pressure Rapid glottis opening, expiratory muscles contract, PEF up to 12 l/s, dynamic compression of airways Specialists in Ventilation & Airway Clearance (Leith 1985)

Normal Cough Specialists in Ventilation & Airway Clearance

Why Assess Cough? Specialists in Ventilation & Airway Clearance

General muscle weakness Decreased chest wall compliance Shortening of respiratory muscles & Chest wall deformity Decreased tidal volumes Respiratory muscle weakness Ineffective cough REM related nocturnal hypoventilation Recurrent chest infections NREM and REM related hypoventilation Daytime hypercapnic respiratory failure Disease Progression

Impact Of Impaired Cough Effective cough is a protective mechanism against respiratory tract infections, which are the commonest cause of hospital admission in patients with respiratory muscle weakness due to neuromuscular disease. (Chatwin et al 2003) Specialists in Ventilation & Airway Clearance

Impact Of Impaired Cough 90% of episodes of respiratory failure develop because of inability to clear the airways in NMD (Gomez-Merino et al 2002) Specialists in Ventilation & Airway Clearance

What Numbers Are Significant? If PCF does not exceed 270 -300 L/min, Patients when they are unwell are at risk of a decline in their PCF < 160 L/min (Bach et al, 1997, Chest) Specialists in Ventilation & Airway Clearance

Impaired Cough Specialists in Ventilation & Airway Clearance

NMD Patient – The Reality Specialists in Ventilation & Airway Clearance

Cough Assessment Specialists in Ventilation & Airway Clearance

How Do We Assess The 3 Cough Phases? Inspiratory Compressive Expiratory • MIP, SNIP, VC • Staccato Expiration from MIC • MEP, FVC, PCF Specialists in Ventilation & Airway Clearance

Normal Values PIMax SNIP PEMax PCF Men > 80 cm. H 2 O Men >70 cm. H 2 O > 360 L/min Women >70 cm. H 2 O Women > 60 cm. H 2 O Men and Women >100 cm. H 2 O (Koulouris et al 1988) (Miller et al 1985) (Koulouris et al 1988) Specialists in Ventilation & Airway Clearance

Stacatto Expiration Specialists in Ventilation & Airway Clearance

Cough Assessment – How ? • Assessing PCF is a quick and easy way of measuring expiratory muscle function • The greater the PCF, the less risk of respiratory complications (Kang & Bach 2000 Specialists in Ventilation & Airway Clearance

Implications of Reduced PCF 1. Recurrent chest infections 2. Risk of aspiration 3. Hospital Admissions 4. Reduced Qo. L 5. Respiratory Failure & Mortality Specialists in Ventilation & Airway Clearance

Which Patients May Be At Risk? At risk patients not currently on HMV Patients ventilated via a trache (Canadian HMV Guidelines 2011) Specialists in Ventilation & Airway Clearance

Introducing Airway Clearance Techniques Specialists in Ventilation & Airway Clearance

When To Introduce Methods PCF <270 l min Select MAC or MIC techniques PCF < 245 l min Combine MAC and MIC PCF < 160 l min MI- E Consider MI-E with MAC Specialists in Ventilation & Airway Clearance Chatwin 2009

Maximum Insufflation Capacity The Maximum Insufflation Capacity (MIC) is a measurement in litres, and is the maximum volume of air stacked within the patient’s lungs beyond spontaneous vital capacity. MIC is attained when the patient takes a deep breath, holds their breath, followed by breath stacking applied using a LVR resuscitation bag, a volume ventilator or glossopharyngeal breathing (GPB). (Le. Blanc & Mc. Kim 2007) Specialists in Ventilation & Airway Clearance

Manual Assisted Cough A manually Assisted Cough Manoeuvre involves the application of an abdominal thrust or costal lateral compression using various hand placements after an adequate spontaneous inspiration or maximal insufflation. (Le. Blanc & Mc. Kim 2007) Specialists in Ventilation & Airway Clearance

An introduction to MI-E Specialists in Ventilation & Airway Clearance

The History of Mechanical Insufflation-Exsufflation MI-E is not a new therapy, it was developed in 1948 by Alvan Barach as a result of the polio epidemic Specialists in Ventilation & Airway Clearance

The History of Mechanical Insufflation-Exsufflation • It was in 1953 that various portable devices were manufactured to deliver MI -E • First publication of the use of MI-E was in 1954. The Beck & Barach reported successful and immediate elimination of large amounts of purulent secretions in a patient with poliomyelitis. Specialists in Ventilation & Airway Clearance

The History of Mechanical Insufflation-Exsufflation • Emerson launched the “Cofflator” in 1950’s which weighed 9 kg Specialists in Ventilation & Airway Clearance

How Does MI-E Work? • MI-E devices clear secretions by applying a positive pressure to the airway – Insufflation • Followed by a rapid shift to negative pressure – Exsufflation • It is the rapid shift in pressure which results in a high expiratory flow (PEF) stimulating a cough • Flows produced need to be sufficient to produce an effective PCF with no effort Specialists in Ventilation & Airway Clearance

Outcomes of MI-E • Assisting secretion mobilisation • Lung volume recruitment • Increasing inspiratory and expiratory force • Cough augmentation Reduced Chest Infections… Reduced Admissions Reduced Cost of Care … Improved Qo. L Specialists in Ventilation & Airway Clearance

Thank You Any Questions ? Specialists in Ventilation & Airway Clearance