COPD & Respiratory Failure

Dr Samir SahuSr Consultant

Critical Care & PulmonologyApollo Hospitals, Bhubaneswar.

Introduction

• The average patient with COPD experiences two episodes of AECOPD per year,

• 10% of these episodes require hospitalization Sullivan SD, Ramsey SD, Lee TA.Chest 2000

COPD exacerbation

• Type 1: severe - worsening dyspnea,

- increase in sputum purulence - increase in sputum volume.

Washington manual of critical care 2008

Initial evaluation

• history,• physical examination,• basic laboratory tests, • chest X ray• ABG.

Clinical Picture

• Signs of muscle fatigue • Paradoxical breathing (an inward motion of

the upper abdominal wall with inspiration)• Respiratory alternans (a cyclic alternation

between abdominal and rib cage breathing),

• suspicion of impending respiratory failure.

COPD-Respiratory Failure

• Oxygenation Failure-V/Q mismatch• Ventilatory Failure -Excessive Respiratory Load -Hyperinflation -Inadequate Inspiratory Muscle Endurance -Length-Tension -Force-Velocity -Fatigue• PO2<50, PCO2>50

AE-COPD- Treatment

BRONCHODILATORS• Rapidly acting B2 agonist & anticholinergic by

Aerosol -Ipratropium 0.25-0.5mg(60-90m) -Salbutamol 2.5-5mg (30-60m) -Terbutaline 5-10mg (30-60m)• Theophyline(if no response) -Aminophyline-0.5mg/Kg/hr inf.

AE-COPD-Treatment

OXYGEN THERAPY• O2 inhalation by nasal cannula/face mask

• Maintain SpO2 88-93%(PO2 55-60)

• Monitor PCO2(may increase in 26%)

• Repeat ABG in 60min.• SpO2 monitoring may be satisfactory if pH &

PCO2 are normal & SpO2 does not fall

• Continue O2 during Nebulization

OXYGEN THERAPY

• OXYGEN CYLINDER -A - 700 lit (2lit/m) - 6hrs -B - 1500 lit (2lit/m) - 11hrs -C - 5000 lit (2lit/m) - 40hrs• PIPED OXYGEN• OXYGEN CONCENTRATOR (5L/m)

• - Flowmeter,

AE-COPD-Treatment

CORTICOSTEROIDS• Parenteral for first 72hrs

(methyl-prednisolone 125mg IV 6hrly)• Followed by Oral Corticosteroid• Gradually taper off over 7-14day• Inhaled steroids are not appropriate

MacIntyre NR. Respir Care 2006

AE-COPD-Treatment

ANTIBIOTICS– Increased Breathlessness– Increased Sputum Volume– Purulent Sputum– pH < 7.35– 7 day course of appropriate Antibiotic– Treating an AECOPD episode early improves the

speed of functional recovery. Saint S, et al: a meta-analysis. JAMA 1995

AE-COPD-Treatment

Clearance of Secretion• Bronchodilators, Antibiotics & Corticosteroids

decrease Secretions.• Expectorants & Mucolytics -No role, may improve symptoms.• Chest Physiotherapy -Ineffective, perhaps detrimental.

Indication of Ventilatory Support

• Deterioration in spite of Medical treatment.• Moderate to severe dyspnoea• Increasing respiratory distress

- RR>24, - accessory muscle use, - paradoxical breathing

• Respiratory Acidosis (pH < 7.37)• Hypercapnia (pCO2 >55mm of Hg)• Severe deterioration in Mental status• PaO2/FiO2 < 200

Peter et al.Ann Intern Med. (2004)

Ventilation in COPD

• Non Invasive Ventilation• Invasive Ventilation as rescue intervention• Invasive Ventilation as first choice• NPPV to speed up liberation from ventilation

AE-COPD- NPPV

SELECTION CRITERIA• Hypercapnic/Hypoxemic Respiratory Failure

unresponsive to conservative treatment • Normal Bulbar function• Ability to clear secretions• Haemodynamically stable• Ability to cooperate with treatment• No facial trauma & upper airway injury

Non Invasive Positive Pressure Ventilation in AECOPD

• The two largest studies of NPPV in AECOPD showed that NPPV reduced the need for invasive mechanical ventilatory support.

Peter et al – a meta-analysis update. Crit Care Med 2002

Lightowler JV. Cochrane sys review & meta-analysis.BMJ 2003

NPPV in COPD

• Recent studies demonstrate that outcomes of severe COPD exacerbations are no worse if treated with NPPV than with endotracheal intubation, indicating that an initial trial with NPPV is not deleterious, even in severely ill COPD patients (hypercapnic coma).

Scala R et al, Chest 2005 Gonzalez D et al, Chest 2005

Conti G et al, Intensive Care Med 2002

Possible NPPV Locations

• Pre-Hospital Setting• Emergency Department• ICU• Step-Down Unit• General Wards• Long-Term Acute-Care Hospitals

NPPV ventilator days - KHL

NPPV - Predictors of Failure• Air leaking, Lack of compliance & toleranceClinical Condition of patient – high Apache II >29• Asynchrony• Copious secretions• GCS <11• pH < 7.25• Respiratory rate >35/min, high baseline HR• Presence of Pneumonia Change in pH in first hour of NPPV

Ambrosino, Thorax 1995, Phua, Inten Care Med 2005,

Khilnani Ind J Crit Care Med 2006

NPPV - Failure

• The failure rate of NPPV in AECOPD is as high as 50%

Jolliet P et al. Crit Care Med 2003

• 20% of COPD AE experience a new episode of Respiratory Failure. Mortality is 91% with continued NPPV compared to 52.6% in those who are intubated & ventilated

Moretti et al (2000), Thorax

NPPV Failure

• The decision to discontinue NPPV and proceed to invasive mechanical ventilatory support is a clinical one usually driven by progressive respiratory acidosis and signs of patient fatigue/discomfort during NPPV.

• Mechanical Ventilation allow the patient to improve sufficiently to take advantage of NPPV which was ineffective earlier

NPPV Outcome-COPD (2000-2010)

• Success – 159/266 (60%) - mean PCO2-71(IQR 54.5-90.6), mean pH-7.295

• Failure - 107/266 (37.5%) – mean PCO2-82(IQR 56.8-107), mean pH-7.285

(Pneumonia 10, Sepsis 5, ARF 5, TBs 5)• Intubated - 53• LAMA – 21• Death – 81 (30.45%)

- DNI 36, Cardiac 8, Withdrawal 5, Refusal 1, delay in intubation 2.

Invasive Ventilation as first-line intervention

• Respiratory arrest• Unable to fix interface• Extreme Obesity• Unable to protect airway• Need for airway suction for copious &

tenacious secretions

Invasive MV – Minute Ventilation

• Reduce tidal volumes (e.g., 5–7 ml/kg) to protect the lung in AECOPD.

• A high peak pressure, even in the presence of acceptable plateau pressures, should be avoided.

• Permissive hypercapnia. Accepting pH values in the 7.0–7.1 range may have little clinical effect on the patient and may be beneficial if the reduced volumes and pressures reduce the risk of VILI

Kavanaugh BP. Am J Respir Crit Care Med 2005

Dynamic Hyperinflation & Auto-PEEP

• To avoid intrinsic PEEP build up due to patient tachypnea, moderate sedation may be required.

• Reducing PEEPi requires reductions in any or all: -reducing minute ventilation(permissive hypercapnia) -a shorter I/E that lengthens the expiratory time -reductions in airway resistance using pharmacologic agents.

• If the PEEPi is causing a significant ventilator breath–triggering load on the patient, judicious amounts of applied circuit PEEP can equilibrate expiratory pressures and thereby reduce this triggering work. Ranieri VM,et al. Intensive Care Med 1995

Intrinsic PEEP (PEEPi)

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ModeVolume Control Automode Admit

patient Nebulizer Status

Additionalvalues

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Recording60 cmH2O

70 l/min

700 ml

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Invasive MV

• Endotracheal tubes significantly reduce aerosol delivery, doses usually are increased

three- to fourfold (or aerosolized continuously) to ensure adequate drug effectiveness.

• Assessment of airway pressures (peak to

plateau gradients) or flow–volume patterns can be used to monitor bronchodilator effectiveness.

KHL Data – Mechanical Ventilation in AECOPD (2000-2008)(92cases)

• Invasive as first choice – 65• Rescue Ventilation after NPPV failure – 27• Median pH at the time of intubation: 7.176

(IQR range: 7.113-7.255)• Median PCO2 at the time of intubation: 115.6

(IQR range:83.8-138.5)• Median Duration of invasive ventilation: 6 days

(IQR range:3-10 days)• Survived – 64(70%),LAMA – 6(6%), Death – 22(24%)

Invasive MV - Weaning

• Daily spontaneous breathing trials should be performed as patients recover, and patients should be managed with comfortable forms of assisted ventilation (e.g., pressure support, pressure assist, or proportional assist) in between the spontaneous breathing trials.

• Having a well defined protocol Vitacca M et al. Am J Respir Crit Care Med 2001

Weaning from Mechanical Ventilation

• NPPV may be used to expedite weaning from invasive ventilation in uncomplicated cases of COPD who fail a trial of spontaneous breathing Nava S, et al. Ann Intern Med 1998 Girault C, et al. Am J Respir Crit Care Med 1999

• Patients failing to wean from MV should be evaluated for critical care myo-neuropathy

Amaya-Villar R et al. Intensive Care Med 2005

COPD - Wean

• Total - 60 cases• Success - 39• Failure – 18

– DNI – 6, Withdrawal - 1• Death - 10

NPPV weaning duration – KHL42/92

Category 10

2

4

6

8

10

12

14

1 day2 days3 days 4 days5 days6 days 7 days 8 days 9 days 10 days1112 days13 days

Noninvasive Ventilation Use for COPD Linked With Lower Death Rates

• The first examination of the patterns and outcomes of NPPV treatment for acute exacerbations of COPD in clinical practice nationwide.

• The authors concluded that there was a more than 4-fold increase in NPPV use accompanied by a decrease in IMV use in the 10 years examined in patients with COPD. The researchers also noted that although mortality rates decreased overall, the rates increased for patients who were transitioned from NPPV to IMV.

• Although NPPV is shown to be efficacious for the treatment of acute exacerbations of COPD, the authors cautioned that patients at high risk for conversion to IMV should be closely monitored with a plan for early intervention if there is no improvement.

Am J Respir Crit Care Med. Published online October 21, 2011

Outcomes of AECOPD

• AECOPD episodes have been shown to accelerate FEV1 decline, to increase mortality (AECOPD episodes are the most common cause of death in COPD), and to have a profound influence on the decline in quality of life scores

• One large survey found an in-hospital mortality rate of 11%

and 1-year mortality rate of 43% in patients with COPD admitted for acute exacerbations . Another recent study found a similar in-hospital mortality rate (8%) and 1-year mortality rate (23%). These mortality figures are much higher for patients requiring ICU admission Connors AF Jr, et al. Am J Respir Crit Care Med 1996

Outcome of AECOPD

• In a large, multicenter study, the need for mechanical ventilation did not influence outcome

in patients with COPD admitted to an ICU. • However, the risk for rehospitalization and

reintubation for patients with COPD is increased markedly after an episode of respiratory failure

requiring mechanical ventilation Seneff MG, et al. JAMA 1995

Disease Trajectory of a Patient with COPD

S ym ptom s

E xacerba tions

E xacerba tions

E xacerba tionsD eteriora tion

E nd o f L ife

50 yrs 55 yrs

Stable Phase

Steady decline in FEV1

Palliative Care & Do not Intubate Patients

• NPPV offers an effective, comfortable & dignified method of supporting patients with end stage disease & acute respiratory failure

• If the patient and/or family desire prolonged survival, then use should be reserved primarily for COPD and congestive heart failure patients.

• On the other hand, if the goal is to palliate, to relieve dyspnea, or to delay death so that affairs can be settled, then NPPV can be used for these as well as other diagnoses.

• However, it should be reassessed frequently and stopped if the goal of palliation is not being met.

Summary

• Respiratory failure in COPD needs proper initial clinical assessment & ABG for assessment of severity & decide modality & location of treatment.

• All patients with severe respiratory failure in COPD should be given a trial of NPPV.

• NPPV is more labour intensive & needs frequent assessment & earlier detection of failure of NPPV.

• If NPPV fails patient should be intubated & mechanically ventilated early & promptly.

Summary cont.

• All measures should be taken to prevent harm to the patient during mechanical ventilation by using lower tidal volumes, & looking for dynamic hyperinflation(autopeep).

• Weaning from Mechanical ventilation should be speeded up by using NPPV.

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