Pulmonary Testing.pptx

Pulmonary Auscultation and Testing Health Assessment Risk Factors for Post-Op Pulmonary Complications 5-10% of all patients have post-operative pulmonary complications 22% of high-risk patients Our job is to determine Who has risk factors What can we do to mitigate those factors Risk Factors History...

Pulmonary Auscultation and Testing Health Assessment Risk Factors for Post-Op Pulmonary Complications 5-10% of all patients have post-operative pulmonary complications 22% of high-risk patients Our job is to determine Who has risk factors What can we do to mitigate those factors Risk Factors History of cigarette use (>40 pack years) ASA 2 or more Age 70 or more COPD Neck, thoracic, upper abdominal, aortic, neuro Long procedures (>2 hours) Planned general anesthesia Inability to walk 2 blocks BMI >30 Heart failure Weight loss Delerium Alcohol use Abnormal chest exam findings BUN >21 mg/dL Albumin < 35g/dL Risk Factors PFTs Good for determining: “Can dyspnea or wheezing be improved further?” “Is dyspnea cause by lung disease of heart failure?” Not useful for determining absolute postoperative risk Should not be used as a risk assessment tool but rather a test for diagnostic reasoning support Pulmonary Function Testing Some take away points: Removal of CO2 is determined by alveolar ventilation, NOT minute ventilation Almost all anesthetics reduce skeletal muscle tone which decreases FRC to levels close to awake RV General anesthesia causes ventilation-perfusion (V/Q) mismatch (airway closure) and shunts (atelectasis) Respiratory physiology is very closely linked to the practice of anesthesia The most serious adverse respiratory outcomes are related to hypoxemia Lung Volumes FRC Amount of air in the lungs after ordinary expiration 3-4L Importance 1. inflating an already opened/inflated lung is easier 2. if lung completely deflates between breaths, blood flowing from closed alveoli would have very low SO2 (same as mixed venous blood) that would mi with overall blood flow and cause major O2 desaturation after every exhalation Spirometry TLC: gas volume in the lung after a maximum inspiration (6-8L) Obstructive disease: increased (up to 10-12L) Restrictive disease: decreased (down to 3-4L) RV: volume left after maximum expiratory effort (2L) VC: maximum volume that can be inhaled and then exhaled (4-6L) VC = TLC-RV Spirometry VC is reduced in both obstructive AND restrictive disease Vt: normal breathing volume Obstructive Lung Disease Upper respiratory infections Asthma COPD Spirometry for Obstructive Disease FEV1: forced expiratory volume in 1 second Volume of air that can be forcefully exhaled in 1 second FEV1 versus predicted 80-120% of predicted is normal FVC: forced vital capacity Volume of air that can be exhaled with maximum effort 3.7-4.7L FEF25-75%: airflow through mid-point of exhalation Spirometry FEV1, Forced expiratory flow, Peek expiratory flow rate FEF25-75% All direct measures of airflow obstruction FEV1