NIV in emergency department
Dr.Venugopalan.P.PDA,DNB,MNAMS,MEM[GWU]
Director ,Emergency Medicine, Aster –DM health care Site Director ,MEM program –GWUDeputy Director –MIMS Academy
Founder and Executive Director -ANGELS
Emcon2014 Mumbai November 6 to 9
What is it?
• Respiratory support given without an ETT
• Spontaneously breathing patients
Emcon2014 Mumbai November 6 to 9
Normal breathing
• Negative pressure• Air drawn when the
Diaphragm descends
Lung capacities
Types • IPPB –intermittent Positive pressure breathing
• CPAP- Continues positive airway pressure
• BiPAP- Bi-level positive airway pressure
CPAP
• High flow oxygen plus PEEP• Raises FRC away from Residual volume • Splints alveoli open -Reduce work of breathing -Increase PaO2 Re-expands atlectasis • Resolution of pulmonary edema
BiPAP
• IPAP +EPAP• EPAP =PEEP• Inspirtory pressure increases Tidal volume Decreases PaCO2 Increases PaO2 Decreases WOB
Terminology
0
4
8
12
16
EPAP
IPAP
Pressure Support
- IPAP: assists in improving tidal volume, thus decreasing CO2- EPAP : improve FRC, helps recruit more alveoli, thus increasing O2. may reduce work of
breathing associated with autopeep
20
10
0
IPAP = 12
EPAP = 4PS = 8
BiPAP
NIV - Changes in EPAP Pressure
5 cm
Delta P 10 cm
10 cm
15 cm
Delta pressure 5 cm
EPAP increased to 10 cm
IPAP increased to 20 cm
Delta P returned to 10 cm
PRESSURE
Decreasing delta pressure will usually result in lower Vt
• Differential in pressure between inspiration and expiration allows for better patient-ventilator synchrony and thus more comfort
• EPAP CPAP PEEP• IPAP PS–Augments TV –Reduces Atelectasis–Reduces WOB
PAV
• New Assist Mode of Ventilation– Fundamentally different concept
• Ventilator Generates Pressure in Proportion to Patient Effort– Follows and adjusts to patient changes
PatientEffort
Pressure
PSV PAV
From Pressure Support to PAV
Non-invasive PAV for Acute Respiratory Insufficiency
• Peter Gay and coll, Am J Respir Crit Care• General ICU• COPD patients with acute exacerbation• 44 patients were randomized to receive NPPV with PAV or Pressure Support (PS)
Mortality and intubation rate were similar but refusal rate was lower with PAV
Reduction in respiratory rate was more rapid with PAV and there were fewer complications in the PAV group
Respiratory Failure • Type 1 –Low PaO2, All else Normal • Type 2 –Low PaO2,High
PaCO2
CPAP or BiPAP
ABG Normal Value
• PH- 7.35 -7.45• PaO2 -10.7 to 13.3 kPa• PaCO2- 5.6 to 6.7 kPa• HCO3 – 22 to 26 mmol• BE- -2 - +2
• Type 1 respiratory failure
• Type 2 Respiratory failure
Hypoxia
CPAP
Hypoxia Hypercapnea
BiPAP
Clinical Benefits
• Type 1 respiratory failure• Type 2 respiratory failure• Pulmonary Edema
Acute
Clinical Benefits
• Weaning • Post intubation
Sub acute
Clinical Benefits• Sleep apnea • Type 2 respiratory failure COPD CF Neuromuscular Disease
Chro
nic
Precautions • Impaired conscious level• Agitation ,Confusion• Consolidation• Copious secretions • Inability to protect airway• Hemodynamic instability • Bowel obstruction• Recent GI surgery
Contra Indications • Need for immediate
intubation• Facial Trauma and Burns • Frequent vomiting • Recent facial /Upper airway
surgery • Undrained pneumothorax
Avoid intubation • No paralysis or sedation• Ability to move –pressure
relief • Able to communicate • Able to eat and drink• Self care • Less need of invasive
monitoring • Less risk of infection
Advantages
No intubation
• Less infection risk • No tracheal Damage • Able to communicate
Decreased need of ICU admin
• Cost • Patient and Care givers
experience• Less debilitating
Implications of Physiotherapy
• Mask fitting • Deoxygenation • Expectoration• Familiarity with Machine
and Alarms
Skills needed • Patient handling
&communication• Knowledge of respiratory
physiology• Familiarity with interfaces • Knowledge of pressure
area care• Time to spend with patient• Patience
NIPPV in COPD
Meta-analysis of fourteen RCT • Decreased mortality (Relative Risk 0.52; 95%CI 0.35 to 0.76) • Decreased need for intubation (RR 0.41; 95%CI 0.33 to 0.53) • Reduction in treatment failure (RR 0.48; 95%CI 0.37 to 0.63)• Less complications associated with treatment (RR 0.38; 95%CI 0.24
to 0.60) • Shorter hospital stay ( -3.24 days; 95%CI -4.42 to -2.06) • “Data from good quality randomised controlled trials
show benefit of NPPV as first line intervention as an adjunct therapy to usual medical care in all suitable patients for the management of respiratory failure secondary to an acute exacerbation of COPD.”
Cochrane Database Syst Rev. 2004
NIPPV &COPD
• Noninvasive ventilation is most effective in patients with moderate-to-severe disease
• Hypercapnic respiratory acidosis may define the best responders (pH 7.20-7.30). – Noninvasive ventilation is also effective in patients with a
pH of 7.35-7.30, but no added benefit is appreciated if the pH is greater than 7.35.
– The lowest threshold of effectiveness is unknown, but success has been achieved with pH values as low as 7.10.
Respir Care. 2005 May• NIV in pts with milder COPD exacerbations: RCT.• Patients with mild COPD + pH of >7.30 were eligible .• MEASUREMENTS: Borg dyspnea index at baseline, 1 hour, and
daily, Length of hospital stay, endotracheal intubation, hospital survival
• RESULTS : NPPV was poorly tolerated, sig. decrease in dyspnea at 1 hour and 2 days, No differences were seen for any measured variable.
• CONCLUSIONS: The effectiveness and cost-effectiveness of the addition of NPPV to standard therapy in milder COPD exacerbations remains unclear.
NIPPV & Cardiogenic pulmonary edema• There are clear benefits in meta-analysis of
randomized trials for CPAP– risk of mortality 0.59 • 95%CI 0.38-0.90
– risk of intubation 0.44 • 95%CI 0.29-0.66
Peter JV, Moran JL, Phillips-Hughes J, Graham P, Bersten AD. Effect of non-invasive positive pressure ventilation (NIPPV) on mortality in patients with acute cardiogenic pulmonary oedema: a meta-analysis. Lancet 2006; 367: 1155–1163.
Rasanen 1985
Finland
40 patients CPAP (20)
V Control (20)
Intubation
Mortality
6/20 v 12/20 17/20 v 14/20
NS
NS
Bersten 1991
Australia
39 patients CPAP (19)
V Control (20)
Intubation
Mortality
0/19 v 7/20
2/19 v 4/20
<0.005
NS
Lin 1991
Taiwan
55 patients CPAP (25)
V Control (30)
Intubation
Mortality
7/25 v 17/30
2/25 v 4/30
<0.05
NS
Lin 1995
Taiwan
100 patients CPAP (50)
V Control (50)
Intubation
Mortality
8/50 v 18/50
4/50 v 6/50
<0.01
NS
Takeda 1998 Japan
22 patients CPAP (11)
V Control (11)
Intubation
Mortality
2/11 v 8/11
1/11 v 7/11
<0.03
0.02
• In CPAP group all studies showed a significant improvement in :
Respiratory statusCardiovascular parametersBlood gas analysis
• No reported complications in any study
Asthma &NIPPV
• Number of studies investigating the use of NPPV in acute asthma exacerbations is limited
• Available data suggests that it is safe .• There are some studies to support the use of BiPAP
for acute asthma exacerbations in the pediatric population .
• Lot of papers that address the question there are • Only 3 completed RCTs and all these have relatively
small numbers. Addition of NIV in treating status asthmaticus is safe
and well tolerated. NIV shows promise as a beneficial adjunct to
conventional medical treatment. further prospective investigation is warranted
NIPPV & Pneumonia
– Noninvasive ventilation not established to be beneficial
– Secretions may be limiting factor– Improvement with noninvasive ventilation best
achieved in patients also with COPD– Hypercapnic respiratory acidosis may define group
likely to respond– Decrease in intubation rate and mortality may be
limited to those also with COPD
Conclusion
• Judicious use of NIV is a useful tool to manage respiratory emergencies
• Close observation and timely interference is absolutely essentials.
• EP and EMS should familiar with equipment , usages and guidelines
…
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