preoperative assessment for cardio thoracic surgery
TRANSCRIPT
PREOPERATIVE ASSESSMENT FOR
CARDIOTHORACIC SURGERY
Group 4
Muhammad Arsalan Khan
Said Khitab Shah
Liaqat Ali
Gauhar Rahman
KMU, IPMS, 3rd batch
Department of Anesthesiology.
Key Points
• Patients for pulmonary resection
• Three pulmonary areas observed
• Lung mechanical function
• Pulmonary parenchymal function
• Cardio pulmonary reserve
• Pulmonary resection surgery
• Patient extubated provided AWaC (alert warm and
comfortable)
• Geriatric patient are at high risk for cardiac complications
i.e. arrhythmias etc.
• Assessment for malignancy done by 4 M’s i.e. mass
effect, metabolic effect, metastases and medication.
Introduction
• Thoracic anesthesia
• Wide variety of diagnostic and therapeutic procedures.
• Involves lungs and other thoracic structures.
• Anesthetic technique have changed as the population of
patient presenting for cardiothoracic surgery have
changed.
• Major causes of morbidity and mortality of thoracic
surgeries are
• Respiratory complications 15-20% i.e. atelectasis, pneumonia etc.
• Cardiac complications 10 -15% morbidity i.e. Ischemia etc.
Initial Preoperative Assessment
• Respiratory complication are the major cause of morbidity
and mortality.
• Following are the initial preoperative assessment for
thoracic surgeries:
Pulmonary Assessment
• Best assessment for respiratory function is done by
• Detailed history of patient quality of life.
• Simple baseline spirometery preoperatively to measure FEV1 and FVC.
• Three legged assessment of lungs• Respiratory mechanics
• Pulmonary parenchymal function
• Cardio respiratory interaction
• Basic functional units for extracellular respiration which get atmospheric O2.
• Into alveoli
• Into the blood
• To the tissue ( reserved for CO2 removal).
Lung mechanical Function
•Spirometery:• Test for respiratory mechanics and volume.• FEV1, FVC, mechanical voluntary ventilation (MVV),
RV/TLC.
• Most valid single test for post thoracotomy respiratory complication is ppoFEV1%.• ppoFEV1%= preop. FEV1x (1- % functional lung tissue
removal /100)
• ppoFEV1% > 40% no or minor complications.
• ppoFEV1% <40% have complication but not in all.
• ppoFEV1% <40% are operated with acceptable morbidity and mortality.
Pulmonary Parenchymal Function• Arterial blood gas data
• PaO2 < 60mmHg
• PaCO2 > 45mmHg
• Pulmonary resection contraindicated.
• Cancer resection can successfully performed under the
above situation.
• Most useful test for gas exchange capacity of lungs is the
diffusing capacity of carbon mono oxide i.e. DLCO
• DLCO is non invasive.
• ppoDLCO% same as ppoFEV1% (<40%) have both
respiratory and cardiac complications.
• DLCO% < 20% unacceptable because of preoperative
mortality rate.
Cardiopulmonary Interactions
• Laboratory exercise testing is gold standard.
• Max. oxygen consumption (VO2) is best predictor of post
thoracotomy outcomes.
• Resting measurement is for 3 to 5 minutes.
• Max. working capacity is reached normally at 8 to 15 min.
• After that limitations are initiated i.e. severe dyspnea,
significant ECG abnormalities.
• Estimation of VO2 is based on age, sex and height.
• Predicted VO2 max (mL/min)= [(height – age)X20] whole divided by weight.
• If VO2 is <15 mL/kg/min , the morbidity and mortality is highly unacceptable.
• Few patients having VO2 max. >20 mL/kg/min have respiratory complications.
• Poor exercise tolerance test is due to pulmonary versus cardiac etiologies.
• Anaerobic threshold 55% of VO2 max. observed in untrained person while it exceeds >80% in trained athletes.
• Repeated blood lactate analysis documents the increase in threshold of CO2production above the initial respiratory quotient (ratio of CO2 production/O2 consumption).
Regional Lung Function
• Assessment of preoperative contribution of lung or lobe to
be resected by imaging of regional lung function.
• For any potential pneumonectomy who has ppo <40%
predicted for 80% of FEV1 and/or DLCO.
• Three techniques done.
• Radionuclide ventilation/perfusion V/Q lung scanning.
• Pulmonary quantitative CT-scanning
• MRI
Combination Of Tests
Final Assessment
• Assessment just prior to the admission of the patient to
the operating room.
Difficult Endobronchial Intubation
• Factors leading to suspicion of difficult endobronchial
intubation are:
Previous radiotherapy
Infections
Pulmonary or airway surgery
• Assessment are made:
Bronchoscopy report
X –Ray, CT- Scan preoperatively
Preoperative chest X-ray of a patient with a
history of
previous tuberculosis, right upper
lobectomy, and recent hemoptysis
presenting for right thoracotomy possible
completion pneumonectomy.
The potential problems positioning a left-
sided double-lumen
tube in this patient are easily appreciated
by viewing the X-ray but
are not mentioned in the Radiologist’s
report. The Anesthesiologist
must examine the chest imaging
him/herself preoperatively to anticipate
problems in lung isolation.
Prediction of Desaturation During
One-Lung Ventilation• Most patients suffer desaturation during OLV.
• Factors correlating are:
• High percentage of ventilation or perfusion to the
operative lung on preoperative
• V/Q scan
• Poor PaO2 during two-lung ventilation, particularly in the
lateral position intraoperatively
• Right-sided thoracotomy
• Normal preoperative spirometery (FEV1 or FVC) or
restrictive lung disease
• Supine position during one-lung ventilation
References
• Preanesthetic Assessment for Thoracic Surgery by Peter Slinger and Gail
Darling (pdf)
• Slinger P, Suissa S, Triolet W. Predicting arterial oxygenation during one-lung
anaesthesia. Can J Anaesth. 1992;39:1030–5.
• Kempainen RR, Benditt JO. Evaluation and management of patients with
pulmonary disease before thoracic and cardiovascular surgery. Semin Thorac
Cardiovasc Surg. 2001;13:105–15.
• Liu SS, Mulroy MF. Neuraxial anesthesia and analgesia in the presence of
standard heparin. Reg Anesth Pain Med. 1998;23(6 Suppl 2):157–63.
• Licker M, Widikker I, Robert J, et al. Operative mortality and respiratory
complications after lung resection for cancer: impact of chronic obstructive
pulmonary disease and time trends. Ann Thorac Surg. 2006;81:1830–8.
• British Thoracic Society. Guidelines on the selection of patients with lung
cancer for surgery. Thorax. 2001;56:89–108.
• Patterson AG. Pearson’s thoracic and esophageal surgery. 3rd ed.
Philadelphia, PA: Elsevier; 2008. p. 1168.