Non-invasive ventilation - BiPAP

NON-INVASIVE VENTILATION

- BIPAP

WHAT WE WILL COVER... Definition Why do we use NIV? Indications for BiPAP use Contraindications to use Patient selection Set up Monitoring Escalation Duration of treatment Weaning Palliation Clinical scenarios

AIM To gain a more in depth knowledge of

BiPAP and it’s clinical indications

OBJECTIVES To state the definition of NIV To list 3 clinical indications to commence

BiPAP To list 3 contraindications for its use To discuss patient selection considerations To be able to correctly describe set up To be able to give clear instructions on

monitoring To be able to relay that an escalation plan

should be documented at commencement

DEFINITION Non invasive ventilation – ‘the provision

of ventilatory support through the patient’s upper airway using a mask or similar device’.

CPAP – continuous positive airway pressure

BiPAP – bilevel positive airway pressure.

WHY USE? NIV in T2RF in COPD - reduction in

mortality ~50%

Reduces intubation rates in COPD pts with decompensated respiratory acidosis

Reduction in need for ICU admission and reduced hospital costs compared to standard medical therapy

CLINICAL INDICATIONS Acute exacerbation of COPD

Persistent respiratory acidosis : PaCO2 > 6kPa, 7.26 < pH <7.35

- despite immediate maximal standard medical treatment on controlled oxygen therapy for no more than one hour

CLINICAL INDICATIONSStandard medical therapy:

Controlled oxygen to maintain SaO2 88-92%

Nebulised salbutamol 2.5 – 5mg Nebulised ipratropium 0.5 mg Prednisolone 30 mg Antibiotics (when indicated)

CLINICAL INDICATIONS Acute / acute on chronic hypercapnic

respiratory failure - chest wall deformity / neuromuscular disease.

Decompensated OSA (esp if respiratory acidosis)

?Acute exacerbation of bronchiectasis ARDS / postoperative, post-

transplantation respiratory failure Weaning from invasive ventilation ?Heart failure / pneumonia

CONTRAINDICATIONS Facial burns / trauma / recent facial or upper airway

surgery Vomiting Fixed upper airway obstruction Undrained pneumothorax Upper gastrointestinal surgery Inability to protect the airway Copious respiratory secretions Life threatening hypoxaemia Haemodynamically unstable requiring inotropes / pressors

(unless in a critical care unit) Severe co-morbidity Confusion / agitation Bowel obstruction Patient declines treatment

SELECTING PATIENT Place in one of 5 groups:

Immediate intubation and ventilationSuitable for NIV and escalation to ICU /

intubation if requiredSuitable for NIV but not suitable for

escalationNot suitable for NIV but for full active

managementPalliative care most appropriate

SELECTING PATIENT Premorbid state Severity of physiological disturbance Reversibility of acute illness Presence of relative contraindications Patients wishes (if possible)

SELECTING PATIENT Inclusion criteria

Sick but not moribundAble to protect airwayConscious and cooperativeNo excessive respiratory secretionsPotential for recovery to quality of life

acceptable to the patientPatient’s wishes considered

SET UP Decision to start – CT2 or above Patient consent Trained staff Initial settings

IPAP – 10 cms H2O 2-5cms increments 5cms every 10 mins target 20 cms or until therapeutic response

achieved / pt tolerability reached EPAP – 4-5 cms H20.

Oxygen (when required) – sats 88 – 92 %

MONITORING Continuous sats, cardiac monitoring

(first 12 hours) RR, HR, BP and GCS ABGs – minimum 1, 4 and 12 hours (1

hour after further changes) Management plan – within first 4 hours

of NIV – ?intubation Compliance with NIV, patient-ventilator

synchrony and mask comfort – KEY FACTORS IN DETERMINING OUTCOME!

Appropriately trained staff

ESCALATION Management plan in event of NIV

failure should be made at outset!

Uncertainty / not for escalation - discuss with a consultant

Escalation appropriate – discuss with ICU team early (ideally intubate first 4 hours)

In late NIV failure (>48 hours) intubation is mx of choice

TREATMENT DURATION Benefit during first hours - NIV for as

long as possible during first 24 hours Tx should last until the acute cause has

resolved, commonly 2 – 3 days If NIV successful (pH> 7.35, resolution

of underlying cause and sx, RR normalized) – appropriate to start weaning

WEANING Tx reduction – daytime periods first After withdrawal in the day, a further

night of NIV is recommended Documentation of weaning strategy in

nursing and medical records

PALLIATION When NIV failed, not for escalation –

need proactive approach to palliation

KEY POINTS NIV works! – evidence based Indicated in AECOPD – respiratory

acidosis (PaCO2>6kPa, pH<7.35 , >7.26) despite 1 hour medical therapy

Select your patients with thought! Ensure no contraindications Think of long term plan when starting

CLINICAL SCENARIOS...

CASE 1 67 yo man with known moderate to severe

COPD Multiple admissions with IECOPD, no ITU

admissions 3/7 hx of productive cough, increasing SOB

& wheeze ABG (on non rebreathe mask put on by

ambulance):pH 7.28, pCO2 9.1, pO2 58HCO3 29.2, BE -2, lactate 1.9

MANAGEMENT?

MANAGEMENT Salbutamol neb 2.5–5 mg Ipratroprium neb 500μg Prednisolone 30mg PO or hydrocortisone

200mg IV (for minimum of 5 days) Antibiotic (if evidence of infection) CXR Consider IV aminophylline Most importantly controlled oxygen

ABG AFTER 1 HOURInitial ABG (100% non re-breathe mask)

ABG at 1 hour (28% venturi mask)

pH 7.28 7.37pO2 58 26.5pCO2 9.1 8.1HCO3 29.2 32BE -2 -1.5Sats 98 88

CASE 1 67 yo man with known moderate to severe

COPD Multiple admissions with IECOPD, no ITU

admissions 3/7 hx of productive cough, increasing SOB

& wheeze ABG (on non rebreathe mask put on by

ambulance):pH 7.28, pCO2 9.1, pO2 58HCO3 29.2, BE -2, lactate 1.9

Initial management as before

ABG AFTER 1 HOURInitial ABG (100% non rebreathe)

ABG at 1 hour (28% venturi)

pH 7.28 7.21pO2 58 26.2pCO2 9.1 11.3HCO3 29.2 28BE -2Sats 98 86

• What now?

NIV NIV should be considered in all patients

with an acute exacerbation of COPD in whom a: respiratory acidosis (pH <7.35, PaCO2 >

6kPa) persists despite immediate maximum standard medical treatment on controlled oxygen therapy for no more than 1 hour

STARTING NIV NIV started at

EPAP 4cm H20 (improves O2) IPAP 10cm H20 (reduces PCO2)O2 level to maintain 88-92% sats

Titrate up to therapeutic setting over 1 hour

IPAP by 2–5cm increments at ~ 5cm H20/10 mins, with usual target of 20 cm H20 or until therapeutic response achieved or patient tolerability reached

Within 1 hour, IPAP target of 18-22cm H20

ABG 2 HOURS POST STARTING NIV

Initial ABG (100% non rebreathe)

ABG at 1 hour (28% venturi)

ABG 2 hrs post starting NIV

pH 7.28 7.21 7.36pO2 58 26.2 18.1pCO2 9.1 11.3 7.2HCO3 29.2 28 24BE -2Sats 98 86 90

• What now?

MARKERS OF IMPROVEMENT ABG at 2 hours showing improved pH &

decreasing pCO2 What next?

If no longer acidotic and pCO2 normalising then don’t stop immediately!

Remain on present settings, repeat ABG in 4-6hrs

Need to wean down the BiPAP over several days – e.g. D1 24hr, D2 16hr, D3 8hr then stop

ALTERNATIVELY…ABG 2 HOURS POST STARTING NIV…

Initial ABG (100% non rebreathe)

ABG at 1 hour (28% venturi)

ABG 2 hrs post starting NIV

pH 7.28 7.21 7.15pO2 58 26.2 23.1pCO2 9.1 11.3 13.5HCO3 29.2 28 27BE -2Sats 98 86 82

• What now?

FAILURE TO IMPROVE Still acidotic & pCO2 not improving

despite therapeutic settings Is this person an ITU candidate?

Consider if development of complicationE.g. pneumothorax, mucus plugging,

aspiration pneumoniaPoor fitting mask, tubing disconnection

CASE 3 57 yo lady with IHD and severe LV

dysfunction Acute onset SOB 2 hours previously Brought to resus – wheezy ++,

accessory muscle use ++, RR 40 ABG:

pH 7.23, pCO2 7.9, pO2 7.1, lactate 3.8, HCO3 18 on 15L non-rebreathe mask

Likely diagnosis? Management?

CARDIOGENIC PULMONARY OEDEMA Management:

O2, morphine, furosemide, GTNCPAP

Reduces preload and afterload through positive intrathoracic pressure, increases SV, decreases HR

Standard is not BiPAP Studies show does improve pH/pCO2/HR/RR/SOB

and intubation rate BUT possible increased MI rate (Mehta S et al,

Crit Care Med 1997; 25:620-628)

SUMMARY Acute exacerbation of COPD

Firstly 1 hour of maximum standard medical treatment

ABG at 1 hour If NIV started then ABG at 1-2 hoursSlow wean down of NIV if improvementConsider complications/ITU if deterioration

BiPAP not standard for pulmonary oedema

REFERENCES Mehta S, Jay GD, Woolard RH, Hipona RA, Connolly EM, Cimini DM, Drinkwine JH, Hill

NS. “Randomized, prospective trial of bilevel versus continuous positive airway pressure in acute pulmonary edema” Critical Care Medicine 1997; 25:620–628

http://www.brit-thoracic.org.uk “Non-invasive ventilation in chronic obstructive pulmonary disorder: management

of acute type 2 respiratory failure” RCP/BTS Concise guideline, October 2008 “NIPPV Non-Invasive Ventilation in Acute Respiratory Failure” British Thoracic

Society Standards of Care Committee; Thorax 2002; 57:192-211 “The Use of Non-Invasive Ventilation in the management of patients with chronic

obstructive pulmonary disease admitted to hospital with acute type II respiratory failure (with particular reference to Bilevel positive pressure ventilation)” British Thoracic Society/Royal College of Physicians London/Intensive Care Society guideline, October 2008

Lightowler JV, Wedzicha JA, Elliott MW et al; “Non-invasive positive pressure ventilation to treat respiratory failure resulting from exacerbations of chronic obstructive pulmonary disease: Cochrane systematic review and meta-analysis.” BMJ 2003; 326:185–7.

Ram FSF, Picot J, Lighthowler J et al. “Non-invasive positive pressure ventilation for treatment of respiratory failure due to exacerbations of chronic obstructive pulmonary disease.” Cochrane Database Syst Rev 2004; 3.