ANE 624- Thoracic Surgery- Part II - Hagerman-Audio

Thoracic Anesthesia Part II: 

ANE: 624 Advanced Principles III University of New England Thoracic Anesthesia Part II

High Risk Patients for Pulmonary Resection Surgery: 

High Risk Patients for Pulmonary Resection Surgery Respiratory complications (e.g. significant atelectasis) most common complication. Followed by cardiac complications.

Predicting Postoperative Pulmonary Function: 

Predicting Postoperative Pulmonary Function Lobes of lung do not contribute equally to gas exchange (depends upon number of subsegments ) Three test must be assessed in all pulmonary resection candidates. Number of stairs more closely associated with decreased mortality

Three Test to Assess: Postoperative Pulmonary Function: 

Three Test to Assess: Postoperative Pulmonary Function FEV1: single most valid test Patients with FEV1 < 40% at significant risk Lung parenchymal function: ABG provide data, most useful test is DLCO2 DLCO <40% increased risk for complications Cardiopulmonary Reserve : gold standard is formal exercise testing and measurement of maximal O2 consumption No perioperative mortality if VO max >15ml/Kg per min Stair climbing good alternative to exercise testing (expensive) 6 min. walk test & exercise oximetry > validation vs. stair climbing Ability to climb > 3 flights

Management: 

Management FEV1> 40% : will tolerate surgery and can be extubated in OR FEV1 30 – 40% : can be extubated if: Adequate exercise tolerance Cardiopulmonary Reserve adequate Diffusing capacity adequate FEV1 <40% : should have ventilation – perfusion scan

Mangement: 

Mangement FEVI 20-30% : can be extubated if have epidural placed and everything else favorable Those that do not meet this criteria should have staged weaning from ventilation in PACU to check work for spontaneous ventilation

Anesthesia For Lung Resection: 

Anesthesia For Lung Resection Pre-Operative: Determine if approach will be thorascopic or via thoracotomy. If thoracotomy: insert epidural for postoperative analgesia. Determine where the cancer is and what type. Want to know if lesion is primary or metastatic Hx: tobacco use, exercise tolerance, dyspnea, cough, sputum Look for signs of pulmonary HTN (loud P2 with wide split S2) Check for signs of PVD –common in heavy smokers

Anesthesia For Lung Resection: 

Anesthesia For Lung Resection Lung function and functional status important elements of preop eval. Check exercise tolerance, room air blood gas, spirometry and DLCO. Look at ECG and CXR results. You will find a relatively large proportion of abnormal results in this population

Anesthesia For Lung Resection: 

Anesthesia For Lung Resection Criteria to determine if patient has adequate reserve to undergo lung resection: If FEV1 <50% FVC < 2L RV/TLV > 50% PaCo2 >40% MBC (Maximum breathing capacity or Max. Voluntary Ventilation nl= 100 ml/min) < 50% If above factors present- lung resection contraindicated UNLESS PFT’s can document that a disproportionate amount of effective ventilation is coming from lung that is not going to be resected.

Abnormal PFT’s : 

Abnormal PFT’s Mortality is inversely related to FEV1. Patients with high FEV1 will do quite well Patients with low FEV1 will require post op ventilation time and may become impossible to extubate.

Importance Of FVC: 

Importance Of FVC A FEV1 of <800 ml is incompatible with life Low FVC or FEV1 suggests limited mechanical reserve An FVC 3x TV is necessary for an effective cough. Mortality is also inversely proportional to FVC An RV/TLC >50% suggests that the pt. has near terminal COPD with airway closing volumes that are approaching TLC. Surgery can be expected to significantly reduce their remaining reserve and may make it impossible to free from ventilator

Lung Resection: Set up: 

Lung Resection: Set up A-line- a must beforehand CVP -optional Have 8.0 or larger ETT available for the bronchoscopy (if done) DLT: only open up one beforehand- very costly Women have a 35, 37 & 39 Fr Left sided tube Men have a 37, 39 & 42 Fr Left sided tube- better to err on side of tube too large- makes FOB easier At least one large bore IV Lower body Bair Hugger Have blood available- Type & Screen (rarely used)

Lung Resection: Positioning: 

Lung Resection: Positioning Proper positioning and padding are essential. These include: Head rest- donut, pillow or rolled up blanket An axillary roll Hips at break on table Bean bag for lateral position Upper edge even with tip of shoulders Pillows or blanket rolls between the lower extremities to prevent compression necrosis of skin overlying bony structures

Lung Resection: Positioning: 

Lung Resection: Positioning Arms: may be positoned on a two-tiered support or have pillows or blankets between to maintain neutral position A strap or tape between the iliac crest and the femoral head to stabilize the lower torso (avoid strap directly over head of femur- asceptic necrosis of femoral head could result)

Lung Resection: Positioning: 

Lung Resection: Positioning Complications of Positioning : Injuries to dependent eye/ear- usually result of protracted compression Superior scapular N injury for inadequate padding of the axilla Atelectasis Asceptic necrosis of femoral head Peroneal N injury

Complications : Lateral Position: 

Complications : Lateral Position

Nerve damage during thoracic surgery: 

Nerve damage during thoracic surgery Intercostal nerve damage is most common. Branches of brachial plexus, RLN and phrenic nerve may be injured (especially the left phrenic nerve because of its anatomical course). The left RLN can be damaged during thoracic aorta surgery. This may lead to vocal cord paralysis.

Post Op Pain: Treatment: 

Post Op Pain: Treatment IV narcotics PCA Thoracic epidural with narcotics or local anesthetics Intrathecal narcotics (single dose) Paravertebral nerve blocks

Lung Resection: Post op complications: 

Lung Resection: Post op complications Postoperative Complications: after thoracotomy and lung resection CV : Dysrhythmias, RV failure, hypotension/hypertension, myocardial ischemia and infarction. Respiratory : bronchopleural fistula, infections, respiratory failure, pulmonary emboli, chest wall complications, pulmonary hemorrhage, pulmonary torsion, tracheostomy problems Pain : inadequate pain control, epidural complications, over sedation and respiratory depression

Anesthesia for Lung Volume Reduction Surgery: 

Anesthesia for Lung Volume Reduction Surgery This is a new type of surgery for patients with disabling emphysema Preoperative Considerations: Successful completion of 6-8 weeks of pulmonary rehab Room set up – includes epidural, a-line , DLT, fluid warmer, central line etc. Be careful with sedation. In preop place epidural and give test dose

Anesthesia for Lung Volume Reduction: 

Anesthesia for Lung Volume Reduction Intraoperative Considerations: Induction These pts. Have hypextended lungs and some degree of bullous disease. Overinflation of lungs or rupture of bullae leading to tension pneumothorax and impairment of venous return is an ever present danger with PPV

Anesthesia for Lung Reduction: 

Anesthesia for Lung Reduction Induction of Anesthesia: Gentle PPV. High index of suspicion for tension pneumothorax 14 g IV ready for needle thoracostomy(2 nd intercostal space;midclavicular line) Judicious fluid bolus prior to induction

Management: 

Management Thoracic epidurals superior to lumbar epidurals for pain control – It reduces respiratory complications!! Important to maintain cardiac output during thoracic epidural sympathetic blockade. On average if pt. ventilated with 100% O2 PaO2 will drop from mean of ~ 400 mmHg to 200 mm Hg without a drop in SAO2 May be indirect correlation between thoracic epidural blockade and decrease of HPV

Anesthesia for Lung Reduction: 

Anesthesia for Lung Reduction Induction : Total narcotic doses should be kept to a minimum to avoid postoperative respiratory depression Perfect positioning of DLT is necessary – anything else not tolerated by pt. N2O avoid Central line can be placed post induction and is used primarily for CVP monitoring and to aid in differential diagnosis of intraoperative hypotension Median sternotomy incision for bilateral volume reduction, unilateral thoracoscopy approach for pt. with asymmetric disease

Anesthesia for Lung Volume Reduction: 

Anesthesia for Lung Volume Reduction Maintenance : Oxygenation is usually not a problem Significant deadspace ventilation is predictable due to pathophysiology and end-tidal CO2 will grossly underestimate arterial PaCO2 Hypercapnea is likely to occur intraoperatively (especially for CO2 retainers) and is not terribly worrisome as long as arterial pH is not dangerously low Nondependent lung will deflate SLOWLY due to poor perfusion in that lung

Anesthesia for Lung Volume Reduction: 

Anesthesia for Lung Volume Reduction Maintenance : Significant obstruction of expiratory flow will be evident on the capnograph – adjust I:E ratio, TV and RR to avoid air trapping Avoidance of high airway pressures as are seen with coughing or bucking on the ETT- pressure cycle ventilator may be required to adequately ventilate pt. and to avoid air leaks (spontaneous respirations will also avoid this problem- want to extubate pt. at or near end of case) Epidural use optional during case- may want to wait until end to avoid contributing to intraoperative hypotension and deeper inhalational anesthsia will provide amnesia in absence of nitrous and versed

Anesthesia for Lung Volume Reduction: 

Anesthesia for Lung Volume Reduction Emergence: Goal is a smooth emergence and ultimate extubation of a comfortable patient! Deep extubation with assisted ventilation by mask Replacement of DLT with SLT while pt. is still anesthetized and paralyzed, (LTA and local anesthetic) Replacement of DLT with LMA and extubation from LMA

Anesthesia for Lung Volume Reduction: 

Anesthesia for Lung Volume Reduction Emergence: Emergence and extubation off DLT Excellent analgesia with local anesthetic via epidural will permit as normal respiratory mechanics as possible and avoid narcotics to hypercapnic pt. (period from surgical closure to extubation can be lengthy 30-60 mins) All patient’s will then be transferred to the surgical ICU

Anesthesia for Lung VolumeReduction : 

Anesthesia for Lung VolumeReduction Postoperative Considerations: 1. reinstitute nebulized bronchodilators and aggressive chest physiotherapy asap Narcotics either epidurally or parenterally are to be strictly avoided An epidural that ceases to function SHOULD NOT BE REFLEXIVELY REPLACED BY PCA Epidural usually stays in for 3-5 days Toradol can be used 30 mg IV or 60 mg IM q6 hours