Perioperative Assessment of Asthma PatientsPresented by Ri 胡殿詮 冉景儀

Instructed by CR 劉治民Date: 2006/03/28

Introduction: Peri-OP Assessment of Asthma Patients

• PPC (postoperative pulmonary complications) of asthmaAtelectasisPneumonia or bronchitisBronchospasm (reflex bronchoconstriction during airway instrumentation)HypoxemiaRespiratory failureProlonged mechanical ventilationIntrapulmonary shuntingPneumothoraxRetained secretions

• Difficulty in PPC research & epidemiologic studyLack of consensus in PPC definition

Objects

• Correlation between anesthesia & PPC• Correlation between surgery & PPC• Preoperative assessment of asthmatic patients• Suggestion for surgical asthmatic patients

Correlation BetweenAnesthesia & PPC

Correlation Between Anesthesia & PPC: GA

• Reflex bronchoconstriction during airway instrumentationASA: severe bronchospasm → 90% death or irreversible brain damage

• Mechanical & functional changes of pulmonary system during GAAlteration in diaphragm movement (more ventilation in upper lung & less ventilation in lower lungs)→ V/Q mismatch→ Shunt & dead-space ventilation, increased AaO2 gradient→ Reduction in FRC→ Atelectatic plaques in dependent portion of lungs

• Airway hyper-responsitivity during GA↓Number & activity of alveolar macrophages↓Mucociliary clearance↓Surfactant release↑Alveolar-capillary permeability↑Activity of pulmonary NOS↑Sensitivity of pulmonary vasculature to neorohumoral mediators

Correlation Between Anesthesia & PPC: GA

• Neuro-muscular blockers↓ Hypoxic drive to ventilateMore common in Pancuronium use

• Neuro-chemical changes during GA↓ Peripheral chemoreceptor response to hypoxemia↓ CNS response to hypercapnia

(both IV & inhaled agent at subanesthetic concentration as 0.1 MAC)

Prolonged postoperative hypoxemia

GA → Increased PPC rate!

Correlation Between Anesthesia & PPC

Strategy• Regional anesthesia

No requirement of airway manipulationLess impact on ventilatory controlNo ”unopposed parasympathetic hyperactivity”No neuromuscular blockade

• Post-OP epidural analgesiaHowever….• No evidence of lower PPC rate in regional anesthesia or post-OP epidur

al analgesia• Warner’s study of > 1500 asthma patients: PPC rates for regional & regi

onal anesthesia were similarWarner DO et al., Perioperative respiratory complications in patients with asthma. Anesthesiology 85 (1996), pp. 460–7

Correlation Between Anesthesia & PPC: GA

• Bronchospasm prevention: Pretreatment with lidocaine & salbutamol

→ significantly attenuate FEV1 decrease

Salbutamol → Lidocaine

Saline → LidocaineSaline → Dyclonine

H. Groeben, M. Schlicht, S. Stieglitz et al., Both local anesthetics and albutamol pretreatment affect reflex bronchoconstriction in volunteers with asthma undergoing awake fiberoptic intubation. Anesthesiology 97 (2002), pp. 1445–1450

Salbutamol → Dyclonine

Correlation BetweenSurgery & PPC

Correlation Between Surgery & PPC

Risk group: thoracic and upper abdominal surgery• Diaphragm dysfunction (due to reflex inhibition of phrenic nerve output)

→ Decreased vital capacity & FRC (~50% of baseline after laparotomy, returning toward normal over 1-2 weeks)

→ V/Q mismatch→ Atelectasis, hypoxemia, etc.

• Surgical trauma → Increased airway tone & reactivity→ Exposure of airway irritants → bronchospasm!

Correlation Between Surgery & PPC

Strategy• Laparoscopic procedures: better or not?

Improved FEV1, FRC, arterial oxygenation, ventilation

However….• Still associated with diaphragm dysfunction• No evidence of PPC rate reduction

Preoperative Assessment of Asthmatic Patients

Preoperative Assessment of Asthmatic Patients

• History taking & Identification of risk group• Pulmonary function test• ABG or other laboratory study

Preoperative Assessment of Asthmatic Patients: Risk

Risk group for PPC • General

Age > 70y/oCigarette smokingRenal failurePoor nutrition

• Asthma relatedRecent asthma attackRecent use of anti-asthma therapy for symptomatic controlPast history of endotracheal intubation for asthma management

• Surgery & anesthesia relatedEmergent surgeryThoracic, vascular, or upper abdominal surgeryBlood loss > 4U PRBC (2000mL)Anesthetic time > 180 minutesGeneral anesthesia with endotracheal intubation

Preoperative physical status of patients according to the American Society of

Anesthesiologists Class Definition

1 A normal healthy patient 2 A patient with mild systemic disease and no functional

limitations 3 A patient with moderate to severe systemic disease that results

in some function limitation 4 A patient with severe systemic disease that is a constant threat

to life and functionally incapacitating 5 A moribund patient who is not expected to survive 24 hrs with

or without surgery 6 A brain-dead patient whose organs are being harvested E If the procedure is an emergency, the physical status is

followed by an E (i.e., 2E)

Preoperative Assessment of Asthmatic Patients: Risk

Kroenke et al.: ASA classification of asthma patients vs. PPC • Class 4: ~46%• Class 3: ~28%• Class 2: ~10%

Preoperative Assessment of Asthmatic Patients

• History taking & Identification of risk group• Pulmonary function test• ABG or other laboratory study

Preoperative Assessment of Asthmatic Patients: PFT

Pulmonary function test: Controversial!• Significance of Pre-OP PFT:

Identification of asymptomatic patients with chronic lung disease, rather than risk stratification of clinically-diagnosed asthmatic patients

• Application in Pre-OP assessmentAssess bronchospasm induced by provocation testResponse to bronchodilators

Preoperative Assessment of Asthmatic Patients: PFT

• H.R. Smith et al.(1992) FEV1 < 80% of predicted values or airway resistance > 0.35kpascal/l/s→ Repeat test 15-20 minutes after beta-2 agonist inhalation→ If improvement >15% → Pre-OP beta-2 agonist

• GINA Workshop Report (updated 2004)If FEV1 < 80% of personal best → brief course of steroidDose: prednisolone 40~60 mg/dayStart time: 1-2 days prior to surgeryEnd time: within 24 hours after surgery

1. H.R. Smith, C.G. Irvin and R.M. Cherniack, The utility of spirometry in the diagnosis of reversible airway obstruction. Chest 101 (1992), pp. 1577–1581

2. GINA Workship Report (updated 2004). Global Strategy for the Asthma Management and Prevention.

Preoperative Assessment of Asthmatic Patients

• History taking & Identification of risk group• Pulmonary function test• ABG or other laboratory study

Preoperative Assessment of Asthmatic Patients: ABG

• Baseline ABG: not necessaryNo help in risk assessment or stratification

• Other laboratory test: no evidence of any improvement in pre-OP assessment for PPC

• Pulse oximetry: non-invasive, cost-effective, supplements the history & PE findings

Suggestions for Surgical Asthmatic Patients

Suggestion: Pre-OP Assessment & Preparation

History taking & risk identification• Age > 70y/o• Cigarette smoking• Renal failure• Poor nutrition• Use of systemic steroid within the past 6 months• Asthma severity• Recent Asthma attack• Past history of endotracheal intubation for asthma management• Emergent surgery• Thoracic, vascular, or upper abdominal surgery• Blood loss > 4U PRBC (2000mL)• Anesthetic time > 180 minutes• General anesthesia with endotracheal intubation• PFT: FEV1 < 80% of personal best

Suggested Protocol: Pre-OP Assessment & Preparation

• Use of systemic steroid within the past 6 months →Regimen: Hydrocortisone 100mg q8h ivStart time: 1-2 days prior to surgeryEnd time: within 24 hours after surgery

• PFT: FEV1 < 80% of personal best →Regimen: Prednisolone 40-60 mg/day poStart time: 1-2 days prior to surgeryEnd time: within 24 hours after surgery

• No need of tapering dose• Prolong post-OP steroid use: increased infection rate, poor

wound healing

GINA Workship Report (updated 2004). Global Strategy for the Asthma Management and Prevention.

Suggested Protocol: Pre-OP Assessment & Preparation

• Wheezing before OPInhaled beta-2 adrenergic agents & corticosteroid→ If no improvement, defer the elective surgery

• Reversible airway obstruction or severe bronchial hyperreactivityRegimen: Methylprednisolone 0.5-1.0 mg/kg po &

Salbutamol 3x2 puffsStart time: 48 hours prior to surgery

1. M.T. Silvanus, H. Groeben and J. Peters, Corticosteroids and inhaled salbutamol in patients with reversible airway obstruction markedly decrease the incidence of bronchospasm after tracheal intubation. Anesthesiology 100 (2004), pp. 1052–1057.

2. International Asthma Report, National Institute of Health, International consensus report on diagnosis and treatment of asthma. European Respiratory Journal 5 (1992), pp. 601–641

Suggested Protocol: Pre-OP Assessment & Preparation

• Pretreatment of combined inhaled beta-2 agonist & systemic corticosteroid

M.T. Silvanus, H. Groeben and J. Peters, Corticosteroids and inhaled salbutamol in patients with reversible airway obstruction markedly decrease the incidence of bronchospasm after tracheal intubation. Anesthesiology 100 (2004), pp. 1052–1057.

Suggested Protocol: Post-OP Care & Management

• Serial ABG & CxR follow up• Peri-OP oxygen supplementation• Incentive spirometry• Adequate pain relief (avoid NSAID in patients with past history of aspiri

n-induced asthma)• Consider theophylline administration (bronchodilator, respiratory stimula

nt, diaphragm inotrope)• Consider post-OP epidural analgesia

Thank you for your attention!

Reference

1. Rock P, Passannante A. Preoperative assessment: pulmonary. Anesthesiology Clinics of North America 2004; 22:77-91.

2. GINA Workship Report (updated 2004). Global Strategy for the Asthma Management and Prevention.

3. Paul C. Tamul, William T. Peruzzi. Assessment and management of patients with pulmonary disease. Critical Care Medicine 2004; 32(4): S137-45.

4. H. Groeben. Strategies in the patient with compromised respiratory function. Best Practice & Research Clinical Anaesthesiology 2004; 18(4): 579-594 .

5. H. Groeben, M. Schlicht, S. Stieglitz et al., Both local anesthetics and albutamol pretreatment affect reflex bronchoconstriction in volunteers with asthma undergoing awake fiberoptic intubation. Anesthesiology 97 (2002), pp. 1445–1450

6. Warner DO et al., Perioperative respiratory complications in patients with asthma. Anesthesiology 85 (1996), pp. 460–7

7. H.R. Smith, C.G. Irvin and R.M. Cherniack, The utility of spirometry in the diagnosis of reversible airway obstruction. Chest 101 (1992), pp. 1577–1581

8. M.T. Silvanus, H. Groeben and J. Peters, Corticosteroids and inhaled salbutamol in patients with reversible airway obstruction markedly decrease the incidence of bronchospasm after tracheal intubation. Anesthesiology 100 (2004), pp. 1052–1057.

9. International Asthma Report, National Institute of Health, International consensus report on diagnosis and treatment of asthma. European Respiratory Journal 5 (1992), pp. 601–641