Approach to Acute Respiratory Problems

1
Approach to Acute Respiratory Problems

• Royal Victoria Hospital
• Stéphane Beaudoin
• Respirology Resident
• PGY5

2
Objectives

• To help residents develop an effective approach
  to the evaluation of dyspnea and hypoxia
• To help residents become more familiar with the
  management of common acute respiratory
  emergencies
• Acute severe asthma
• Massive hemoptysis
• Pneumothorax

3
Approach to Dyspnea some Pearls

• Dyspnea is a complex subjective sensation
• Dyspnea ? tachypnea
• Dyspnea ? hypoxemia
• Dyspnea must be differentiated from
• Pain
• Fatigue
• Weakness, deconditioning
• Hence, a complaint of dyspnea must be qualified
  and quantified
• Departure from baseline and progression in time
• Specific impairments
• Use of a standardized scale MRC, NYHA

4
MRC Dyspnea Scale
5
Combined Approach to Dyspnea

• Respiratory
• Upper airways
• Anaphylaxis / Foreign body / tumor
• Vocal cord dysfunction
• Lower airways
• Anaphylaxis / Foreign body / tumor
• Bronchospasm / exacerbation of obtructive lung
  disease / toxic inhalation / infection
• Chest wall / Pleura
• Effusion / tumor / PTx
• Parenchyma
• Infectious, inflammatory, neoplastic disorder /
  CHF
• Vasculature
• PE, chronic pulmonary HTN
• Cardiovascular
• CHF, arrhythmia, effusion/tamponade, valvvular
  dysfunction
• Shock

6
The 6 Causes of Hypoxemia

• Low O2 content of inspired gas
• High altitude
• V/Q mismatch
• Alveolar filling or airway obstruction or
  vascular anomalies
• Shunt
• Pulmonary (AVM, lobar / lung collapse) or
  extra-pulmonary (PFO)
• Hypoventilation
• Central, neuromuscular, myopathic, obesity,
  chronic lung disease
• Low DLCO
• Interstitial lung disease, Pulm HTN
• Low Mixed Venous O2 sat
• Shock / low output state

7
V/Q mismatch and hypoxemia
8
The A-a Gradient

• The efficiency of gas exchange can be assessed by
  comparing the measured arterial oxygen pressure
  (PaO2, via ABG) to the hypothesized ideal or
  maximal alveolar oxygen pressure
• A-a gradient PAO2- PaO2
• PAO2 FiO2 x (Patm- PH20) (PACO2 / RQ)
• Under conditions of normal gas exchange (no V/Q
  anomalies / minimal shunt and normal DLCO), the
  difference between those is small
• A normal A-a gradient in the face of hypoxemia
  narrows the differential to
• Low inspired O2 content
• Hypoventilation
• Limitations
• Normal or expected A-a gradient varies with age
  
• A-a gradient 2.5 (0.21 x age)
• FiO2, RQ, PH2O are imprecise in most clinical
  situations and the full equation is actually more
  complex

9
Approach to Hypoxemia

• ABCs, iv access, O2, monitoring
• Airway difficulty assessment
• Clinical assessment
• Relevant history
• Meticulous physical exam
• CXR
• ABG for pCO2 and A-a gradient

10
Acute Severe Asthma
11
Acute Severe Asthma

• Predictors of a life-threatening attack
• Prior ICU stay or intubation / 2
  hospitalizations or gt 3 ER visits in past year
• Poor perception of symptoms by pt
• Frequent use of relief bronchodilators
• Low SES / Psychiatric illness, drug use
• Cardiovascular or respiratory comorbidities
• All that wheezes is not asthma!
• DDx
• CHF / bronchiolitis / toxic inhalation
• Foreign body aspiration / tumor / anaphylaxis
• PE, pneumonia, PTx
• Vocal cord dysfunction
• Hyperventilation
• Flow rates are absolutely required for diagnosis
  and are the best method to follow the evolution
  of an attack

12
Acute Asthma

• ABCs, iv, O2, monitoring
• Airway difficulty assessment
• Clinical Assessment
• Markers of severity
• Silent chest
• Pulsus paradoxus
• Hypoxemia / hypercapnia (beware of normocapnea)
• RR gt 25-30 / HR gt110 / inability to speak
• FEV1 lt 30 predicted
• CXR is of low yield (done to exclude
  complications or alternative diagnoses)
• Flow rates are absolutely required for diagnosis
  and are the best method to follow the evolution
  of an attack
• ABG should be done if hypoxemia is present, in
  cases of severe distress, or if admission is
  contemplated

13
Acute Asthma Management

• Criteria for admission
• Presence of risk factors for life-threatening
  attack
• Pre-therapy FEV1 lt 25
• Post-therapy FEV1 lt 40
• Hypoxemia / persistent markers of severe attack
• Bronchodilator use more frequent than q 4hr
• The GBS indicator
• A mild attack is defined by
• Mild symptoms
• the absence of markers of severity
• the normalization of flow rates post initial
  therapy
• salbutamol use less than q 4h
• A mild exacerbation can be treated with a
  four-fold increase in ICS dose or a course of
  oral steroids ( as part of a written action plan)

14
Acute Asthma Management

• Bronchodilators MDI with spacer as effective as
  nebulized
• Salbutamol
• MDI 4-8 puffs q 20 min then q 1h
• Neb 2.5-5 mg q 20 min then q 1h
• Ipratropium provides an added bronchodilator
  effect acutely
• MDI 4-8 puffs q 20 min then q 1h
• Neb 500 mcg q 20 min then q1 h
• Corticosteroids dosing is controversial, but
  40-60 mg likely sufficient
• Route po is equivalent to iv and is preferred
  unless pt is vomiting
• Duration 7-14 days, no taper
• Need for higher iv doses in ICU pts is not clear
• Magnesium sulfate
• May provide a modest additional bronchodilation,
  but its impact on outcome is not clear
• Most effective in severe airflow limitation, if
  response to bronchodilators is poor
• Methylxanthines have no role in acute setting

15
Acute Asthma Management

• NIPPV
• Very limited data a cautious and supervised
  trial is reasonable
• Intubation
• no clear decision rule global clinical picture
  and progression should be used as guide
• Can induce laryngospasm or worsened bronchospasm
• Can cause marked hypotension
• Ketamine is a good induction agent due to its
  bronchodilator effects
• Ventilation strategies
• Ensure adequate sedation (and paralysis if
  necessary)
• The goal is normalization of gas exchange and
  reduction of the barotrauma risk
• Low RR 6-10/ min / IE ratio gt2 / high
  inspiratory flow rates
• Low Vt max 8cc / kg
• Cautious use of PEEPe 50-80 of PEEPi (esp if
  spontaneous mode used)

16
The 5 Commandments of Asthma

• Identify and address potential triggering factors
• URTI, non-compliance, smoking, irritant exposure,
  allergies, NSAIDS, beta-blockers
• Review and optimize puffer technique
• Prescribe ICS to all pts
• Educate pt about his illness
• Vaccinate for Influenza at least

17
Massive Hemoptysis
18
A case

• 62 F known for some chronic lung disease
• Presented with 180 cc of fresh hemoptysis over
  1.5 day, in context of purulent secretions and
  worsened dyspnea (MRC 2?3)

19
Massive Hemoptysis
20
Massive Hemoptysis
21
Massive Hemoptysis

• Definition is controversial 100 cc/24h to 1,000
  cc/24h
• Rate of bleeding should also be considered
• Consequences such as hypoxemia, need for
  admission / intubation should also be considered
• Only 5-15 of all hemoptysis cases are considered
  massive
• Mortality is significant
• Up to 38 in recent studies
• Significant epistaxis and UGI bleed must first be
  excluded
• The importance of the little cup

22
Massive Hemoptysis

• Etiology relative frequencies vary considerably
  based on center/population
• Most common causes
• Bronchiectasis
• TB
• Mycetoma
• Lung Malignancy
• Diffuse alveolar hemorrhage (hemoptysis can be
  minimal)
• Idiopathic
• Others
• Anatomic origin
• Bronchial arteries ? 90
• Non-bronchial arteries ? 5
• Pulmonary vessels ? 5

23
Massive Hemoptysis

• Management Goals
• Stabilize the respiratory and hemodynamic status
• Identify the site of bleeding
• Identify the cause of bleeding
• Treat the underlying cause and / or perform
  active procedures to abort bleeding
• In palliative situations
• Relieve anxiety, dyspnea, psychological distress
• Green surgical towels and morphine iv

24
Massive Hemoptysis

• ABCs, iv access, O2, monitoring
• ICU admission
• Correct coagulopathy and hemodynamics
• X-match and keep units in reserve
• Focused Hx and physical exam
• CXR / CT with angio protocol (aortogram)
• Bronchoscopy goal is localization of bleeding
• Timing is controversial
• Bronchoscopic interventions are temporizing at
  best

25
Massive Hemoptysis Management

• Supportive care is crucial
• Bleeding side down (lateral decubitus)
• Intubation required if resp failure is present or
  if very large amount of blood expectorated
• Largest ETT possible
• Seek help for selective intubation with either
  single or double-lumen tube (if bleeding side
  known)
• Otherwise immediate bronchoscopy for localization
  and airway clearance
• First line definitive procedure is Bronchial
  Artery Embolization
• Surgery now reserved for refractory cases despite
  multiple embolizations, trauma, PA rupture,
  mycetoma

26
Bronchial Artery Embolization
27
Massive Hemoptysis Special Case

• 83 M 3 hrs post CABG x 3, MAZE, redo MVR, TV ring
  annuloplasty
• Called for large amount of fresh blood coming
  from ETT
• What is the cause?
• What should be done?

28
Pneumothorax
29
18 M with chest pain and mild dyspnea for 1 week
30
Review of Physiology

• Under normal conditions, the tendancy of the lung
  to collapse and the tendancy of the chest wall to
  expand produce a negative pressure in the pleural
  space
• This acts as a vacuum (or recoil pressure) that
  keeps the lung and the chest wall in close
  proximity and prevents lung collapse (due to
  principle of transmural pressure)
• When the pleural space is disrupted and the
  pressure is allowed to equilibrate with
  atmospheric pressure, this recoil pressure is
  altered (or even eliminated)
• The lung and the chest wall tend to return to
  their resting positions

31
Classification

• Spontaneous Primary PTx in a patient without
  apparent underlying pulmonary disease
• Thought to be caused by the rupture of an
  air-containing space within or in vicinity to the
  visceral pleura, usually at the apex
• Although patients have no apparent underlying
  lung disease, up to 80 have blebs or bullae on
  CT examination
• Male sex, smoking, tall stature, and genetics are
  risk factors
• Recurrence rate of 39 in ipsilateral lung and
  15 in contralateral lung
• Spontaneous Secondary PTx in a patient with
  underlying pulmonary disease
• Almost any lung condition can be associated with
  the development of a PTx
• COPD is by far the most common etiology nowadays
• Although the exact mechanism varies, the
  principles underlying the development of primary
  PTx are likely also playing a role (exacerbated
  by airway/parenchymal inflammation and
  architecture disruption)
• Recurrence rates are usually higher and depend on
  the underlying etiology
• Traumatic Pneumothorax
• (including iatrogenic)

32
Pneumothorax Clinical Features

• History
• Acute onset of pleuritic chest pain, usually at
  rest, /- dyspnea
• Symptoms can be out of proportion to the extent
  of lung collapse, especially in secondary
  pneumothorax where the reserve is limited
• Trauma (even blunt) to exclude
• Physical Exam
• Hypoxemia
• Severe hypoxemia due to shunting rare in primary
  PTx 25
• Major alterations in vitals usually only seen in
  tension PTx
• Hyperexpanded hemithorax with ?resonance, yet
  ?excursion, ? vesicular sounds and fremitus
• Contralateral tracheal deviation s/c emphysema
• Hamman sign clicking/crunching sounds with heart
  beats influenced by position and respiration

33
Tension Pneumothorax

• Tension PTx is a clinical diagnosis
• Evidence of sudden deterioration in a patient
  known to have a PTx or highly suspected of having
  one should prompt initiation of therapy
• severe hypoxemia, tachycardia, contralateral
  tracheal shift, ? JVP, shock
• Radiologic signs are not specific
• Caused by a one-way valve phenomenon producing a
  positive pleural pressure during most of the resp
  cycle
• Main consequence is reduction of venous return/
  cardiac output
• Treatment consists of oxygen administration and
  immediate needle aspiration in 2nd ICS at
  mid-clavicular line and insertion of a chest tube

34
Radiological Diagnosis

• A standard erect PA CXR is sufficient
• Expiratory views are only marginally more
  sensitive and are not recommended for routine use
• A sharply demarcated white pleural line without
  lung markings lateral to it is diagnostic
• Mimickers skin fold, tubings, ribs
• Use of expiratory views /lateral decubitus views
  if unclear
• A pleural effusion is present in up to15-25 of
  cases (usually an eosinophilic pleuritis in
  reaction to the presence of air rarely
  hemorrhagic)
• Supine patients
• Deep sulcus sign / upper quadrant lucency /
  ?sharpness of cardiac border or hemidiaphragm
• CT scan recommended only if
• Diagnosis suspected despite normal CXR
• To better define underlying disorder

35
Pneumothorax in a supine patient
36
Pneumothorax Size Estimation

• Several quantification/measurement methods exist,
  and none is perfect
• Most show good correlation, but poor agreement
• Standard is measurement by CT volumetrics
• Size estimation methods
• Light Index
• PTX 1 (lung diamater3/hemithorax diameter3)
• Rhea Method
• PTx determined by plotting the average of 3
  interpleural distances on a nomogram
• Collins Method
• PTX 4.2 4.7 x ( sum of interpleural
  distances)

37
Pneumothorax Size Estimation

• Measurement methods proposed by the BTS and ACCP
  to classify PTx as small/ large
• ACCP large defined as 3cm apex to cupola
• BTS large defined as gt 2cm lung to chest wall at
  hilar level
• From MacDuff et al.Management of spontaneous
  pneumothorax BritishThoracic Society pleural
  disease guideline 2010. Thorax 201065(Suppl
  2)ii18eii31. figure 1

38
Management

• Good quality evidence to guide clinical decision
  making is lacking
• Data from available evidence difficult to compare
  due to the use of
• Different measurement methods
• Different definitions/ decision thresholds
• Guidelines produced by the BTS and the ACCP as
  well as recommendations from major textbooks
  differ in many apsects and are largely based on
  expert consensus
• Nevertheless, there has been a shift towards more
  conservative initial treatment and reliance on
  patients status rather than PTx size
• In general, treatment is more aggressive in
  secondary PTx cases

39
Management Initial Therapy

• All sources agree that asymptomatic patients with
  small PTx (primary or secondary) should be
  managed conservatively and observed
• The exact observation period and the follow up
  schedule is not well-established ( the ACCP
  recommends 3-6hrs of observation and f/u CXR the
  next day)
• Unless contraindicated, all patients should
  receive high concentration oxygen therapy
• Can lead to a 4-fold increase in the reabsorption
  rate
• Smoking cessation is of crucial importance

40
Question

• How long does it take for a 25 PTx to resolve?
• The reabsorption rate varies from 1.25-2.2 of a
  hemithorax volume per day
• Hence it would take 12-13 d to resolve completely!

41
Management of Primary PTx

• For large primary spontaneous PTx, opinions
  differ
• ACCP Drainage via pigtail or chest tube
• Connected to either a water-seal system or a
  Heimlich valve
• Reliable patients with good re-expansion can be
  discharged
• BTS Drainage only if symptomatic
• Via needle aspiration (effective in 60)
• Pigtail if aspiration fails or gt 2.5L aspirated

42
Management of Secondary PTx

• For asymptomatic patients with large PTX or
  symptomatic patients with PTx of any size,
  opinions again differ
• ACCP Drainage with chest tube (pigtail
  acceptable)
• BTS Drainage with pigtail (aspiration less
  effective)
• For asymptomatic patients with small PTx, initial
  observation is recommended

43
55 M post TTNA
44
65 F with DAH, post IJ line
45
Post-resolution Management

• Return to normal activities allowed when free of
  symptoms
• Return to contact sports/ heavy exercise upon
  complete resolution of PTx
• Air travel recommendations (BTS guidelines)
• No evidence that air travel precipitates
  recurrence
• If no surgery is performed, patients may wish to
  wait one year given that most recurrences occur
  1yr
• If surgery is performed, travel is safe upon
  recovery
• Waiting at least one week after CXR resolution is
  recommended (2 weeks if traumatic)
• Diving recommendations (BTS guidelines)
• Presence of blebs/bullae are a contra-indication
• Previous spontaneous PTx is a contra-indication
  unless a bilateral surgical pleurectomy performed
  with normal lung Fx and CT post op

46
Summary

• An affective approach to dyspnea / hypoxemia is
  the key to an accurate diagnosis
• The management of asthma starts by the exclusion
  of alternative diagnoses, risk stratification,
  and early bronchodilator and corticosteroid
  therapy
• The management of massive hemoptysis consists of
  patient stabilization, localization of the
  bleeding and identification of its cause, all
  leading to definitive interventions
• The management of a pneumothorax depends on its
  type, its size and its clinical consequences
• A tension PTx is a clinical diagnosis and
  required prompt intervention

47
Useful References

• 2010 CTS Asthma Guidelines
• 2010 GINA Asthma Guidelines
• Analytic review management of life-threatening
  asthma in adults. Mannam P, MD Siegel. Journal of
  intensive Care Medicine 2010.
• Massive Hemoptysis An update on the role of
  bronchoscopy in diagnosis and management. Sakr
  L, Dutau H. Respiration 2010.
• 2010 BTS guidelines for Pneumothorax Evaluation
  Management