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Arterial Blood gas interpretation pH pH PaCO2 PO2 on FIO2 =…. then PCO2 for acid-base balance – for an acute change in PCO2 of 10, the pH goes 0.08 units in the other direction. PCO2 and PO2 and FIO2 for gas exchange Examples of AcidBase Imbalance: Bicarbonate is never measured, it is calculated from the HendersonHesselbach equation using measured pH and paCO2 Describe the Acid-Base Imbalance (1): pH=7.42, PaCO2 PCO2=48 is slightly high pH is on the alkaline side of normal This is most probably a compensated metabolic alkalosis Describe the Acid-Base Imbalance (2): pH=7.36, PCO2=52 PaCO2 is high pH is normal, but on the acid side of 7.40 This is most probably a compensated respiratory acidosis Describe the Acid-Base Imbalance (3): pH=7.20, pH PCO2=52 is quite acid PaCO2 is less high than you expect for a pure respiratory acidosis, (PCO2 up by 12, pH should go down by ~ .10 units) this is a mixed acidosis Assessment of Gas Exchange: Question: While breathing room air, a comatose hyperpneic youth arrives in the ER. He is pink. An ABG shows: – pH=7.15; PCO2=20, PO2=95 Acid-base status? Acute Metabolic Acidosis Are his lungs normal? NO as A-a DO2 is The Flow-Volume loop 1 2 A. Normal – Identify » 1 Peak flow rate » 2 RV » 3 TLC What is B? 3 The Flow-Volume loop A. Normal B. Restrictive C. Large airway fixed obstruction D. Small airways variable obstruction E. Extra-thoracic variable obstruction Exercise Testing: Stage I Screening Quantitate exercise capacity c.f. predicted Assess oxygen saturation on exertion Factors limiting Exercise – Pulmonary Mechanics – Pulmonary Vascular – Cardiac or peripheral (including unfitness) – Anxiety Inhaler Devices: Dry powder inhalers (DPI) - (Diskus or Turbuhaler or Handihaler) Pressurized Metered Dose Inhalers(Freon-free) (HFA MDIs) eg Advair 250, Qvar,Salbutamol, Mometasone – pulmonary deposition may be improved – side-effects decreased Patients still need careful instruction in the use of any inhaler device Inhaled Steroids: (IS) Fluticasone (Flovent) , Budisonide (Pulmicort), Ciclesonide (Alvesco) all have similar local side effects sore throat, thrush, dysphonia ( try a spacer and do a swish, gargle and spit) (Ciclesonide may be exception) Enough absorption to cause bruising Inhaled Steroids (IS): Potential sideeffects if long-term, high dose therapy: Cataracts, Osteoporosis – osteoporosis prevention may be important with children on high dose IS, but not adults. – Inactivity due to uncontrolled asthma promotes osteoporosis also Delayed growth Adrenal insufficiency Long-lasting B2 Agonists (LABAs): Examples: – Salmeterol (Serevent) 25 ug p ii bid – Formoterol (Oxeze) 12 ug p i bid Second-line drug for ongoing acute bronchospasm despite optimal inhaled steroids Decreases nocturnal exacerbations Does not eliminate the need for short-acting B2-agonists Not a rescue medication Combination IS/LABA: Examples: – Advair discus(fluticasone + salmeterol – Symbicort turbuhaler (budisonide + formoterol Indication in Asthma: – When IS in doses of 500-1000 ug/day are insufficient to eliminate frequent rescue with SABAs Indication in COPD: – May increase interval between AECB . Leukotriene Antagonists Montelukast (Singulair) 10 mgm qhs Block leukotriene-derived mediators (SRS-ALTC4 and LTD4, but not prostaglandins Montelukast is accepted for children down to age 6 years (5 mgm strength) It is helpful in a minority of asthmatics Leukotriene Antagonists Role: – a second line drug – If inhaled steroids are insufficient to control symptoms or are contra-indicated – May help: » ASA-sensitive individuals » restore sense of smell (Systemic distribution) » may be useful to prevent progressive asthma Side effects - None IgE Antagonists: Omalizumab (Xolair) Monoclonal antibodies block action of IgE on mast cell Effective if IgE levels are only slightly elevated (500-1200) Monthly injection Extremely expensive ?$45,000/year Use if frequent need for oral steroids despite optimum conventional Rx and patient has drug plan or $$$ Acute asthma, ER management Mild: B2 agonist; start IS Moderate: add O2, oral steroids Severe: add continuous B2 aersols, Ipatropium, 100% O2 Near death: add intubation, ventilation, kitchen sink (Theophylline, MgSO4, Halogenated anesthetic) Discharge criteria: track record, response to B2 agonists, prior steroids, compliance Chronic asthma management Minimal: B2 agonist prn. Mild: add inhaled steroids Moderate : – Leucotriene antagonist – long lasting B2 agonist – Short course oral prednisone Severe: – add oral steroids dose large enough, duration long enough to return patient to “personal best” – “Bronchial barbecue”- bronchial thermoplasty Asthma Consensus Guidelines Next edition Treatment Continuum ?2009 ** µg Additional Therapy * 0 250 500 10001500 Short-acting ß2-agonist on demand Environmental Control and Education Very Mild Mild Moderate Moderately Severe Severe Preclinical Intermittent Persistent * ß2 agonist need < 3 times/week (excluding 1 dose/day before exercise) ** ICS dose required > 400-500 mcg/day (as beclomethasone equivalent) LABAs, LTRAs ?Pred. Dose Lower COPD 4% of Canadians 4th leading cause of death Over 40 years of age Mortality rate rising, especially for females Occasionally occupation causes COPD COPD Guidelines Do not screen asymptomatic smokers Assess with spirometry if symptomatic – – – – Cough SOBOE wheeze persisting colds FEV1/ Do FVC< .7 ABG if FEV1 <40% predicted COPD-Assesment: (FEV1/ FVC< .7) Mild– SOBOE if hurrying >80% 50%<80% Severe – SOB on ADL – Resp failure – R CHF FEV1% predicted Moderate – Stops after walk of few minutes Very Severe – SOB at rest 30%<50% <30% Continuum of COPD Management CTS guidelines, Canadian Respiratory J 2008;SuppA 15:1-8 COPD- Management Education Smoking cessation Pharmacotherapy Regular exercise is part of therapyEducation! Inhaled steroids only for repeated AECB responding to prednisone Smoking Cessation Counseling If patient is motivated to quit : +/- Nicotine replacement (patch, gum, etc) -(doubles success) +/- Bupropion (Zyban) start 1week prior to quit day (doubles success) +/- Combination =4x as successful(40%non smokers after 1 year, c.f. 10%) Champix (varenicline tartrate) –a pseudonicotine new kid on the block Champix (varenicline tartrate) Pseudonicotine ..more effective than Bupropion initially Side efect nausea 15-30% Dose: (half in renal disease) – .5 mgm qd x 3d – .5mgm bid x 4 d then D/C cigarettes – 1 mgm bid x 12 weeks Cost: $3.37/day (~ to “patch”; c.f. $1.84/day for Zyban) Inhaled Anti-Cholinergics: Tiotropium (Spireva) Useful in COPD – significant increase in Vital Capacity – may help FEV1 Supplants Ipatropium (Atrovent) as DPI No side effects (?glaucoma exacerbation) Dose: 18 ug tablet DPI inhaled qAM via Handihaler Not a limited use drug COPD long-term management - continued Bronchodilators – B2 (SABA-> LABA) – and/or Ipatropium/Tiotropium Steroids: only 10% respond - document response! Combination IS/LABA may increase time between exacerbations Theophyllines: popularity fluctuates Annual Influenza vaccination ? Pneumovax q 5-10 years COPD long-term management - continued Long-term O2 prolongs life: – if PaO2= or<55 mmHg – if SpO2= or<88% – if pulmonary hypertension, polycythemia, nocturnal desaturation PaO2<60, SpO2<90 – Palliative grounds allowed Antibiotics for purulent bronchitis – Trimethoprim, Tetracycline, Clavulin, Cefuroxime, Clarithromycin, respiratory quinolone COPD long-term management - continued Rehabilitationcomplex) Breathing exercise! (GOYA to exercises (? unproven) Surgery: – Lung Volume reduction » extra 2 years survival – Lung transplantation » No longer smokes » Even if alpha 1 pt. » Patient not on a ventilator » Median survival 2-4years AECB= Acute exacerbation of Chronic Bronchitis Over 50% associated with infections Average of 2 AECBs/year Diagnose if patient has 2 or 3 of the following symptoms: – Increase in Dyspnea – Increase in sputum volume – Purulent sputum Management of AECB Usual bronchodilator Rx Prednisone 25-50 mgm x 7-14 days Antibiotics will attenuate the AECB – Faster resolution of clinical criteria and Peak Flow Rates, reduced LOS* – Choice based on antibiotic hx and local factors *Anthonisen NR, et al.: Ann Intern Med 1987; 106(2):196-204. Microbiology of AECB: Most Common Pathogens by Class Mild COPD – H. influenzae, other Haemophilus species, S. pneumoniae, M. catarrhalis Moderate COPD with risk factors – Class I pathogens – Klebsiella sp. – Increased likelihood of beta-lactam-resistance Severe COPD, – needs hospitalization – Class I and II pathogens – Increased risk of P. aeruginosa AECB: Antibiotic Therapy Simple – COPD mild-moderate; FEV1 >50% pred – RX: Tetra, Amoxi, Cephalosporin GI or GII, Macrolide GII or GIII (clarithromycin or telithromycin) Complicated – COPD severe; FEV1 <50% pred – Any of » <4 AECB/year, Chronic O2 rx, Recent antibiotics, CAD, other chronic illness – RX: Respiratory quinolone, (Gemflox, Levoflox, Moxiflox) Acute on chronic respiratory failure Determine cause – ?Pneumonia – ?AECB – ?CHF – ?Sedatives Assess with spirometry and ABG Oxygenate temperately: avoid greed Drugs: as per asthma, plus Ipatropium (Atrovent) –Pathogens in CAP Outpatients Inpatients Nursing Home S. Pneumoniae H. Influenzae Atypicals (2)* S. pneumoniae H. Influenzae Atypicals (3)** GNR S. pneumoniae H. Influenzae Atypicals (3) ** GNR** * Atypicals (2) = M. pneumoniae, C. pneumoniae ** Atypicals (3) = M. pneumoniae, C. pneumoniae, Legionella spp. GNR = Gram negative rods ** Negated in EU guidelines CAP: Selecting Treatment Type of pneumonia Modifying factors and/or pathogens First-choice therapy Second-choice therapy Outpatient w/out modifying factors — Macrolide Doxycycline Outpatient w/ modifying factors – COPD (no recent anti-biotics or oral steroids within past 3 months) – COPD (recent antibiotics or oral steroids within past 3 months)—H. influenzae & enteric Gram-negative rods – Suspected macroaspiration— oral anaerobes Macrolides Doxycycline Respiratory fluoroquinolone Amox/clav + macrolide or 2nd-gen. cephalosporin + macrolide Amox/clav +/- macrolide, or 4th-gen. cephalosporin 3rd-gen cephalosporin + clindamycin or metronidazole S. pneumoniae, enteric Gramnegative rods (?), H. influenzae Respiratory fluoroquinolone alone or amox/clav + macrolide 2nd-gen. cephalosporin + macrolide Nursing-home residents in nursing home Mandell LA, et al.: Can J Inf Dis 2000; 11(5):237-47. Adopted by the CIDS and the CTS CAP: Selecting Treatment (cont’d) Type of pneumonia Modifying factors and/or pathogens First-choice therapy Inpatient ward — Resp quinolone ICU – Pseudomonas negative Resp. quinolone plus B-lactam/B-l inhibitor or cefotaxime Pseudomoonas positive Cipro plus antipseudomonal Blactam Mandell LA, et al.: Can J Inf Dis 2000; 11(5):237-47. Alternative –Cephalosporin + Macrolide –Macrolide plus –ceftriaxone or Blactam/B-l inhibitor –Antipseudomonal B-lactam plus –aminoglycoside plus –macrolide Pulmonary Arterial Hypertension - Classification Ideopathic -includes Collagen vascular disease, portal hypertension, HIV, anorexogens Secondary to Pulmonary venous hypertension - esp CHF Hypoxemic related PAH Thrombo-embolic PAH Pulmonary Arterial Hypertension: Diagnosis Unexplained exertional dyspnea Isolated impairment of DCO Exercise test Echocardiogram Specialized tests (one or more of): – Spiral CT – V/Q scan – Pulmonary angiogram Pulmonary Arterial Hypertension: Therapy of Primary PHtn Refer to specialty clinic Oxygen if indicated Medications – …Calcium channel blockers – Epoprostenol (prostacycline analog) – Bosentan (endothelin antagonist) – Sildenofil (PDE5 inhibitor) Lung transplantation Dyspnea management in palliation: Reverse what can be reversed Oxygen for hypoxemia or preemptive Opiates – Morphine oral »15-120 mgm q12h »s/c route 5-10 mgm q1-6h. – Dilaudid s/c .5-1.0 mgm q1-6h Obstructive Sleep Apnea Syndrome Heavy snoring Daytime hypersomnolence Obesity Other manifestations: – Hypertension – Unexplained Cor Pulmonale – Nightmares – Impotence – Depression Obstructive Sleep Apnea Syndrome Diagnosis: Sleep – – – – – – study or Polysomnography EEG to stage sleep Electro-oculography EKG Oronasal airflow Respiratory effort SpO2 Obstructive Sleep Apnea Syndrome RDI= Respiratory disturbance index = # of apneas or hypopneas/hr Mild OSARDI 5-15 Moderate OSA RDI 16-30 Severe OSA RDI >30 Therapy: – Weight reduction – CPAP / BiPAP – Mandibular Prosthesis, Tracheostomy LMCC topics understressed Hemoptysis: – Refer if major (>200 ml / 24 hours) – Treat the cause – Antibiotics Pleural – – – – effusion Treat the cause Drain if pus Pleurex indwelling catheter if chronic Pleurodesis if cancer prognosis>3 months and pleurex support not available