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 Specialists in Ventilation & Airway Clearance ‘‘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

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

Requirements For A Normal Cough Specialists in Ventilation & Airway Clearance

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

An Effective Cough Specialists in Ventilation & Airway Clearance (Leith 1985) Glottis open, rapid Inhalation, % of TLC 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 Inspiratory Phase Compressive Phase Expiratory Phase

Normal Cough Specialists in Ventilation & Airway Clearance

Why Assess Cough? Specialists in Ventilation & Airway Clearance

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

Impact Of Impaired Cough Specialists in Ventilation & Airway Clearance 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)

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

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

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? Specialists in Ventilation & Airway Clearance MIP, SNIP, VC Inspiratory Staccato Expiration from MIC Compressive MEP, FVC, PCF Expiratory

Normal Values Specialists in Ventilation & Airway Clearance PIMaxSNIPPEMaxPCF Normal Values Men > 80 cmH2O Women >70 cmH2O (Koulouris et al 1988) Men >70 cmH2O Women > 60cmH2O (Miller et al 1985) Men and Women >100 cmH2O (Koulouris et al 1988) > 360 L/min

Stacatto Expiration Specialists in Ventilation & Airway Clearance

Cough Assessment – How ? Specialists in Ventilation & Airway Clearance 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

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

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

Introducing Airway Clearance Techniques Specialists in Ventilation & Airway Clearance

When To Introduce Methods Specialists in Ventilation & Airway Clearance 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 Chatwin 2009

Maximum Insufflation Capacity Specialists in Ventilation & Airway Clearance 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). (LeBlanc & McKim 2007)

Manual Assisted Cough Specialists in Ventilation & Airway Clearance 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. (LeBlanc & McKim 2007)

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 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 9kg 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 QoL Specialists in Ventilation & Airway Clearance

Thank You Any Questions ? Specialists in Ventilation & Airway Clearance