preoperative pulmonary evaluation and management
DESCRIPTION
This slide presentation covers areas about physiology of respiratory system related to surgery and anaesthesia, definition of postoperative pulmonary complications (PPCs), risk of PPCs, screening for PPC risk and specific management for patients with increased risk.TRANSCRIPT
Preoperative Pulmonary Evaluation and Management
S a n t i S i l a i r a t a n a , M D
Related Pulmonary Physiology
Pulmonary Function System Mechanics
1
Nerve impulse from
brain
2
Respiratory muscle
contraction
3 4 5
Intrathoracic pressure change &
Inspiratory flow
Respiratory muscle
relaxation(contraction) & lung recoils
6
Gas exchange
Intrathoracic pressure change &
Expiratory flow
Lung Volume Definitions
Total lungcapacity (TLC)
Vitalcapacity
Tidalvolume
Inspiratorycapacity
Functionalresidual capacity
Inspiratoryreservevolume
ExpiratoryreservevolumeResidual
volume
Closing Volume
The volume in the lungs at which its smallest airways collapse
The air remaining in the lung = Residual volume
Beyond equal pressure point (EPP) intrapulmonary pressure > intraairway pressure
⬇ airway collapse
Changes of FRC and CC: Conditions
Decreased FRC Spine position
Obesity Pregnancy
General anesthesia Abdominal pain/splinting
Increased CC Advanced age
Smoking COPD
Pulmonary edema
Goldman DR, Brown FH, Guarnieri DM (eds) Perioperative Medicine. New York, McGraw-Hill, 1994.
Changes in Pulmonary Function with Surgery
Diaphragm function Gas exchangeLung volumes Control of
breathingLung defense mechanisms
Reduction in lung volumes
Diaphragmatic dysfunction
Impaired gas exchange
Respiratory depression
Impaired cough reflex and
mucociliary function
Lung Volume Changes
50-60% Reduction
of vital capacity
30% Reduction
of functional residual capacity
for up to1 week
Diaphragmatic Function
DECREASED sympathetic reflexes
vagal reflexes splanchnic receptor responses
Diaphragmatic: irritation
manipulation splinting
immobilization
Diaphragmaticdysfunction ⬇
Basal lung atelectasis ⬇
V/Q mismatching
Gas Exchange
Low lung volume ⬇
Decreased FRC ⬇
Decreased airway radius ⬇
Atelectasis ⬇
V/Q mismatching
Control of Breathing
Residual effects of preanesthetic or
anesthetic agents
Depression of hypercapnid/hypoxic
ventilatory drive from narcotics
Decreased tidal volume Reduced minute ventilation
Increased PaCO2 Decreased frequency of sigh breaths
Precipitation of sleep apnea
Lung Defense Mechanisms in Perioperative Period
coughing Mucociliary clearance
Damage of cilia and mucous gland
by ET tube and/or inhaled anaesthetics
Decreased clearance velocity
by ET tube
Suppression of cough
by opioids
Reduced muscle strength due to neuromuscular blocking agents
InfectionV/Q mismatchingAtelectasis
Postoperative Pulmonary Complications
Definition of Postoperative Pulmonary Complications
3 Exacerbation of underlying chronic lung disease
Infection (Acute tracheobronchitis, pneumonia)2
1 Atelectasis
5 Thromboembolic disease
4 Prolonged mechanical ventilatory support/respiratory failure
Factors Associated with PPCs
PPCs Preoperative
Post- operative
Intra- operative
Chronic lung disease (esp. COPD)
Upper respiratory tract infection
Age Smoking
General health status Nutritional status
Heart failure pulmonary hypertension
Obesity obstructive sleep apnea
Type of anaesthesia Duration of anaesthesia
Surgical site Type of surgical incision
Inadequate pain control
Immobilization
Age
Age
≥80
70-79
60-69
50-59
Odd Ratio of developing pulmonary complications0 2 4 6 8 10
1.5
2.28
3.9
5.63
Smetana GW, Lawrence VA, Cornell JE, American College of Chest Physicians. Ann Intern Med 2006; 144: 581.
Age >50 years was an important independent factor of riskPreoperative Facto
rs
Smoking
Preoperative Facto
rs
Relative Risk (RR)for postoperative complications
!
1.73 (95% CI 1.35-2.23)
American Society of Anesthesiologist: Physical Status Classification
Preoperative Facto
rs
Class Description
ASA 1 A normal healthy patient
ASA 2 A patient with mild systemic disease
ASA 3 A patient with severe systemic disease
ASA 4 A patient with severe systemic disease that is a constant threat to life
ASA 5 A moribund patient who is not expect to survive without the operation
ASA 6 A declared brain-dead patient whose organs are being removed for donor purposes
ASA class >2 confers
!
4.87X increased risk
(95% CI 3.34-7.10)
Chronic Obstructive Pulmonary Disease
Preoperative Facto
rs
Increased sputum
production
Airway inflammation
and edema
Loss of radial traction & Elastic recoil
Decreased airway radius
!
Increased closing volume
6Xmore likely to have
major postoperative pulmonary complications
Asthma
Preoperative Facto
rs
Patients with asthma who are well controlled
and have a peak flow measurement of >80% predicted
can proceed to surgery with average risk
Obesity
Chest wall recoil ~ Lung elastic recoil➡Outward ~ Inward⬅
@balance = FRC
Decreased chest wall recoil ➡Outward < Inward ⬅⬅
@new balance = decreased FRC (ERV)
Preoperative Facto
rs
Effects of Obesity on Pulmonary Function
Low lung volume ⬇
Decreased FRC ⬇
Decreased airway radius ⬇
Atelectasis ⬇
V/Q mismatching
However, obesity has NOT consistently been shown to be a risk factor for PPCs
Obesity should NOT affect patient selection for otherwise high-risk procedure
Preoperative Facto
rs
Obstructive Sleep Apnea
Preoperative Facto
rs
Odd Ratio (OR)for postoperative respiratory failure
1.95 (95% CI 1.91-1.98)
Higher incidence of: Unplanned ICU transfers
Longer length of stay Pneumonia
Respiratory failure
Heart Failure
Pulmonary congestion ⬇
Decreased compliance ⬇
Low lung volume ⬇
Decreased airway radius ⬇
Atelectasis ⬇
V/Q mismatching
⬅ Airway edema
Odd Ratio (OR)for postoperative complications
2.93 (95% CI 1.02-8.43)
Preoperative Facto
rs
Surgical Site
Intraoperativ
e Factors
Esophagectomy
Upper abdominal surgery
Lower abdominal surgery
Complication rates
18.9%
19.7%
7.7%
Type of Anesthesia
Intraoperativ
e Factors
General anesthesia leads to a !
HIGHER RISK !
of clinically important pulmonary complications
than does epidural or spinal anesthesia
Rodgers A, Walker N, Schug S, et al. BMJ 2000; 321: 1493.
Preoperative Evaluation & Risk Assessment
Assessment tools
History & PE
Chest x-ray
Lung function
tests
Risk Indices
Obesity: Body Mass Index (BMI)
Mallampati grade
Asthma: Level of control
ACT, ACQ
COPD: CAT, mMRC
Exacerbation
Spirometry
Lung Volume study, DLCO
Polysomnography
Arozullah respiratory failure
index
Canet risk index
ASA class
Gupta calculator
History & Physical Examination
COPD !
CAT score/mMRC History of exacerbation
Decreased laryngeal height increased AP diameter
Wheezing/rhonchi
Obesity/OSA !
Body mass index Mallampati class
Epworth Sleepiness Score !
Asthma !
ACT score, Level of control History of exacerbation
Wheezing/rhonchi
Chest Radiograph
Patient without risk factorPatient with risk factors
(cardiac or pulmonary diseases)
0.3% Abnormality
detected22%
Abnormality detected
Rucker L, Frye EB, Staten MA. JAMA 1983; 40: 1022.
Pulmonary Function Tests
Patients with COPD or asthma with uncertain optimal symptom/disease control
Patients with unexplained dyspnea or exercise intolerance
2006 American College of Physicians guideline:
NOT to be used as the primary factor to deny surgery NOT to be routinely ordered
Qaseem A, Snow V, Fitterman N. et al. Ann Intern Med 2006; 144: 575.
Arozullah Respiratory Failure Index
Preoparative predictor Point value
Abdominal aortic aneurysm 27
Thoracic 21
Neurosurgery, upper abdominal, peripheral vascular 14
Neck 11
Emergency surgery 11
Albumin <3.0 g/dL 9
BUN >30 mg/dL 8
Partially or fully dependent functional status 7
History of chronic obstructive pulmonary disease 6
Age >70 years 6
Age 60-69 years 4
Type of surgery
General health status
Age
Performance of the Arozullah Respiratory Failure Index
Class Point total Percent respiratory failure
1 ≤10 0.5
2 11-19 1.8
3 20-27 4.2
4 28-40 10.1
5 >40 26.6
Arozullah AM, Daley J, Handerson WG, Khuri S. Ann Surg 2000; 232: 242.
Canet Risk Index
Factor Adjusted odds ratio Risk score
Age ≤50 years 1 0
51-80 1.4 (0.6-3.3) 3
>80 5.1 (1.9-13.3) 16
Preoperative O 1 0
91-95% 2.2 (1.2-4.2) 8
≤90% 10.7 (4.1-28.1 24
Respiratory infection in the last month 5.5 (2.6-11.5) 17
Preoperative anemia (Hb ≤10 g/dL) 3.0 (1.4-6.5) 11
Canet J, Gallart L, Gomar C, et al. Anesthesiology 2010; 113: 1338.
Canet Risk Index
Factor Adjusted odds ratio Risk score
Surgical incision in upper abdomen 1 0
>80 5.1 (1.9-13.3) 16
Duration of surgery ≤2 hours 1 0
2-3 hours 2.2 (1.2-4.2) 8
>3 hours 10.7 (4.1-28.1 24
Emergency surgery 5.5 (2.6-11.5) 17
High risk (42.1%) ≥45 points
Moderate risk (13.3)%) 26-44 points
Low risk (1.6%) <26 points
Pulmonary complication rate:
Gupta Calculator for Postoperative Respiratory Failure
http://www.qxmd.com/calculate-online/respirology/postoperative-respiratory-
failure-risk-calculator
Gupta H, Gupta PK, Fang X, et al. Chest 2011; 140(5): 1207-15.
Perioperative Risk Evaluation: Obstructive Sleep Apnea
Factor PointsA. Severity of sleep apnea based on sleep study (or clinical indicator)
None 0Mild 1Moderate 2Severe 3
B. Invasiveness of surgery and anaesthesiaSuperficial surgery under local or peripheral nerve block without sedation 0Superfacial surgery with moderate sedation or general anaesthesia 1Peripheral surgery with spinal or epidural anaesthesia 1Peripheral surgery with general anaesthesia 2Airway surgery with moderate sedation 2Major surgery, general anaesthesia !
3Airway surgery, general anaesthesia 3
Perioperative Risk Evaluation: Obstructive Sleep Apnea
Factor Points
C. Requirement for postoperative opioids
None 0
Low dose oral opioids 1
High-dose oral opioids, parenteral or neuraxial opioids 3
Total score (Score in A plus the greater of the score for either B or C)
Gross JB, Bachenberg KL, Benumof JL, et al. Anesthesiology 2006; 104: 1081-93.
Significantly increased risk 5-6 points
Increased risk 4 points
Low risk <4 points
Risk Assessment: Non-resective-lung Surgery
History and physical examination Seeking known risk factors for pulmonary complications
Low risk: Proceed to surgery without
further evaluation
Positive Negative
Identify risk(s) presents in the patient
Chest x-ray* Pulmonary function test*
Moderate risk: Perioperative treatment
to reduce risk
Normal
High risk: Reconsider indication for
surgery Perioperative treatment
to reduce risk Consider shorter procedure
Consider epidural/spiral anesthesia
Abnormal
Perioperative Management
Stepwise Approach
What is/are the risk(s)?
Type of: Surgery Incision
Anesthesia
General perioperative management
Specific perioperative management
Strategies to Reduce Postoperative Pulmonary Complications
Preoperative measures Smoking cessation Bronchodilators*
Systemic corticosteroids* Antibiotics*
Inspiratory muscle training Chest physical therapy
Patient education
Intraoperative measures Spinal/Epidural anesthesia
Short-acting neuromuscular blockers
Briefer procedure Endoscopic/Laparoscopic
procedures Lung protective ventilation
Postoperative measures Deep breathing
Incentive spirometry CPAP
Pain control
Smoking Cessation
status of surgery patients and rapid referral to a smoking-cessation program could maximize the cessation period be-fore surgery, resulting in greater reductions in postoperativecomplications in the secondary care setting.
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Figure 3 Meta-regression plot, effect of time of cessation on complications.
153Mills et al Smoking Cessation Reduces Perioperative Complications
Mills E, Eyawo O, Lockhart I, et al. Am J Med 2011; 124:144.
Relative Risk (RR)for postoperative complications
!
0.81 (95% CI 0.70-0.93) in former smokers
!
0.59 (95% CI 0.41-0.85)
in patients who had ≥4 weeks smoking cessation
Even cessation of smoking for 2 days may have some benefits: less carboxyhemoglobin, less effects from nicotine,
improved mucociliary clearance
Deep Breathing & Incentive Spirometry
Equally effective (deep breathing vs incentive spirometry)
50% reduction of postoperative pulmonary complications
Incentive spirometry is recommended after upper abdominal and thoracic surgery
Continuous Positive Airway Pressure
Improved oxygenation Reduced incidence of pneumonia, intubation, and admission to an ICU
However, CPAP may cause patient discomfort gastric distension
barotrauma
Zarbock A, Mueller E, Netzer S, et al. Chest 2009; 135: 1252.
commended as a secondary intervention for refractory atelectasis
⬇
Specific Management: COPD
Continue current medications (if stable)
Give regular bronchodilator therapy (Ipratropium/Tiotropium) for 24 hr prior to surgery until 24 hr postextubation
Give systemic steroid (e.g. dexamethasone 4 mg iv) 1-2 doses 12 hr prior to surgery in severe symptomatic patient or patient with frequent exacerbation
Continue systemic steroid for 3-5 days in severe cases (but no more than 7 days)
Specific Management: Asthma
For patient with controlled asthma: Continue current asthma medications Apply inhaled rapid-acting beta agonist 2-4 puffs or nebulizer treatment within 30 minutes of intubation Give nebulizer treatment in the perioperative period (~24 h after extubation)
For patient with partly or uncontrolled asthma: Systemic glucocorticoid (e.g., dexamethasone 4 mg) 1-2 doses in 12 hour prior to surgery may be used Systemic glucocorticoid may be continued for 3-5 days in severe cases
Specific Management: Morbid Obesity
Administer induction drugs, opioids, and neuromuscular agents using ideal body weight (IBW) NOT total body weight
Positioning in “ramped” and “reversed Trendelenberg” position
Awake intubation in patient when mask oxygenation is inadequate
Application of 100% oxygen with PEEP 10 cmH2O for 5 minutes before the induction of anesthesia ± PEEP 10 cmH2O thereafter
Preoperative Evaluation for Lung Resection
General Evaluation Steps
1 2 3
4
5
Spirometry DLCO
Predicted postoperative FEV1
Predicted postoperative DLCO
Simple exercise test
Cardiopulmonary exercise test
FEV1 2 L for pneumonectomy
FEV1 1.5L
for lobectomy
>80% of Predicted normal
DLCO >80% predicted
PPO FEV1>60% predicted
!
PPO DLCO >60% predicted
>400 m shuttle walk test
!
>22 m stair climbing test
Unexplained symptoms?
>30%
<30% VO2 max >20 mL/kg/min
Averaged risk Increased risk High risk