Presentation on theme: "Dr. Rajesh Kumar University College of Medical Sciences & GTB Hospital, Delhi."— Presentation transcript:
Dr. Rajesh Kumar University College of Medical Sciences & GTB Hospital, Delhi
Indication/contraindication of OLV Physiological changes of OLV Lung separation techniques and equipments
One-lung ventilation, OLV, means separation of the two lungs and each lung functioning independently. OLV provides: Protection of healthy lung from infected/bleeding one Diversion of ventilation from damaged airway or lung Improved exposure of surgical field OLV causes: More manipulation of airway, more damage Significant physiologic change and easily development of hypoxemia
Absolute Isolation of one lung from the other to avoid spillage or contamination Infection Massive hemorrhage Control of the distribution of ventilation Bronchopleural fistula Bronchopleural cutaneous fistula Surgical opening of a major conducting airway giant unilateral lung cyst or bulla Tracheobronchial tree disruption Life-threatening hypoxemia due to unilateral lung disease Unilateral bronchopulmonary lavage
Relative Surgical exposure ( high priority) Thoracic aortic aneurysm Pneumonectomy Upper lobectomy Mediastinal exposure Thoracoscopy Surgical exposure (low priority) Middle and lower lobectomies and subsegmental resections Esophageal surgery Thoracic spine procedure Minimal invasive cardiac surgery (MID-CABG, TMR) Postcardiopulmonary bypass status after removal of totally occluding chronic unilateral pulmonary emboli Severe hypoxemia due to unilateral lung disease
Upright position LDP, lateral decubitus position
Distribution of ventilation
Physiological (postpulmonary) shunt About 2-5% CO, Accounting for normal A-aD02, 10-15 mmHg Including drainages from Thebesian veins of the heart The pulmonary bronchial veins Mediastinal and pleural veins Transpulmonary shunt increased due to continued perfusion of the atelectatic lung and A-aD02 may increase
Protective influences in response to the obligatory pulmonary shunt includes the hypoxic pulmonary vasoconstriction, HPV. HPV, a local response of pulmonary artery smooth muscle, decreases blood flow to the area of lung where a low alveolar oxygen pressure is sensed.
The mechanism of HPV is not completely understood. Vasoactive substances released by hypoxia or hypoxia itself (K+ channel) cause pulmonary artery smooth muscle contraction HPV is graded and limited, of greatest benefit when 30% to 70% of the lung is made hypoxic. But effective only when there are normoxic areas of the lung available to receive the diverted blood flow
HPV is inhibited by: volatile anesthetics (not N 2 0), vasodilators (NTG, SNP, dobutamine, many ß 2 -agonist), increased PVR and hypocapnia PEEP, vasoconstrictor drugs (preferentially constrict normoxic lung vessels)
Double-lumen endotracheal tube (DLT) Single-lumen ET with a built-in bronchial blocker, Univent Tube Single-lumen ET with an isolated bronchial blocker Arndt (wire-guided) endobronchial blocker set Balloon-tipped luminal catheters Endobronchial intubation with a single-lumen ET
Type: Carlens, a left-sided + a carinal hook White, a right-sided Carlens tube Bryce-Smith, no hook but a slotted cuff/Rt Robertshaw, most widely used All have two lumina/cuffs, one terminating in the trachea and the other in the mainstem bronchus Right-sided or left-sided available Available size: 41,39, 37, 35,32, 28,26 French (ID=,10.0,9.5,9.0, 8.5, 8.0, 7.0 and 6.5 mm respectively)
Schematic diagram depicting passage of the left-sided double-lumen endotracheal tube in a supine patient. A, The tube is held with the distal curvature concave anteriorly and the proximal curve concave to the right and in a plane parallel to the floor. The tube is then inserted through the vocal cords until the bronchial cuff passes the vocal cords. The stylet is then removed. B, The tube is rotated 90 degrees counterclockwise so that the distal curvature is concave anteriorly and the proximal curvature is concave to the left and in a plane parallel to the floor. C, The tube is inserted until either mild resistance to further passage is encountered or the end of the common molding of the two lumens is at the teeth. Both cuffs are then inflated, and both lungs are ventilated. Finally, one side is clamped while the other side is ventilated and vice versa
1. Blind technique Caution: DLT should pass without any resistance Optimal depth of insertion for a left sided DLT is ~ patients height ~ 12 +(patients height/10) cm Direct vision technique: uses fiberoptic bronchoscope, however both methods results in successful placement in approx equal number of patients
Alternately blocking the tracheal and bronchial lumen and checking for the air entry. With the help of fiberoptic bronchoscopy Chest –x ray
Margin of safety is low : 1. Rt. Upper lobe bronchus is short 2. Rt. u/l bronchus originates at a distance of 1.5-2 cm from the carina Fewer indications Doughnut shaped cuff Additional opening for the ventilation of right upper lobe.
Distorted anatomy of the entrance of a left main stem bronchus External or intraluminal tumaour compression Descending thoracic artery aneurysm Site of surgery involving the left main stem bronchus Left lung transplantation Left sided tracheobronchial disruption Left sided pneumonectomy Left sided sleeve resection
Most commonly used The bronchial lumen is longer, and a simple round opening and symmetric cuff. Better margin of safety than Rt DLT Can be used Left lung isolation: clamp bronchial + ventilate/ tracheal lumen Right lung isolation: clamp tracheal + ventilate/bronchial lumen
Developed by Dr. Inoue Movable blocker shaft in external lumen of a single- lumen ET tube Easier to insert and properly position than DLT (diff airway, C-s injury, pedi or critical pts) No need to change the tube for postop ventilation Selective blockade of some lobes of the lung Suction and delivery CPAP to the blocked lung
Invented by Dr. Arndt, an anesthesiologist Ideal for diff intubation, pre-existing ETT and postop ventilation needed Requires ETT > or = 8.0 mm Similar problems as Univent Inability to suction or ventilate the blocked lung
Single-lumen ETT with a balloon-tipped catheter Including Fogarty embolectomy catheter, Magill or Foley, and Swan-Ganz catheter (children < 10 kg) Not reliable and may be more time-consuming Inability to suction or ventilate the blocked lung Endobronchial intubation of single-lumen ETT The easiest and quickest way of separating one lung from the other bleeding one, esp. from left lung More often used for pedi patients More likely to cause serious hypoxemia or severe bronchial damage
OPTIONSADVANTAGESDISADVANTAGES Double lumen tube 1.Direct laryngoscopy 2.Via tube exchanger 3.Fibre optically Quickest to place successfully Reposition rarely required Bronchoscopy to isolated lung Suction to isolated lung CPAP easily added Can alternate OLV to either lung easily Placement possible without bronchoscopy Size selection more difficult Difficult to place in difficult or in abnormal trachea Not optimal for postop ventilation Potential laryngeal trauma Potential bronchial trauma Bonchial blocker Arndt Cohen fugi Size selection rarely an issue Easily added to regular ETT Allows ventilation during placement Easier placement in DA and children Postoperative two-lung ventilation easy Selective lobar lung isolation possible CPAP to isolated lung possible More time needed Repositioning needed more often Bronchoscope essential nonoptimal Rt lung isolation Bronchoscopy to isolated lung impossible Minimal suction to isolated lung Difficult to alternate OLV to either lung
OptionsAdvantagesDisadvantages Univent tubeSame as BBs Less repositioning compared with BBs Same as BBs ETT portion has higher airflow resistance than regular ETT ETT portion has larger diameter than regular ETT Endobronchial tubeLike regular ETTs, easier placement in patients with DA Longer than regular ETT Short cuff designed for lung isolation Bronchoscopy neseccary or placement Does nat allow for bronchoscopy, suctioning or CPAP to isolated lung Difficult right lung OLV Endotracheal tube (ETT) advanced into bronchus Easier placement in patients with difficult airways Does not allow for bronchoscopy, suctioning or CPAP to isolated lung Cuff not designed for isolated lung Extremely difficult right OLV
5%-8% of patients with primary lung carcinoma have a carcinoma of the pharynx as well Many of these patients have previous radiation exposure or previous surgery done. They might have distorted anatomy at or beyond carina. eg…descending thoracic aortic aneurysm, intraluminal or extraluminal tumour Can be detected by chest-x ray and CT scan
A flexible fiberoptic bronchoscopy is essential Primary goal is to establish an airway with the help of a SLT (awake or anesthetised) f/b the insertion of bronchial blockers. An alternative is to insert a SLT and then insert DLT with the help of a tube exchanger
1. Insertion of a SLT f/b an independent bronchial blocker 2. Use of a disposable cuffed tracheostomy cannula with an independent bb passed coaxially 3. Replacement of the tracheostomy canula with a short DLT such as NARUKE DLT 4. Placement of a small DLT through tracheostomy stoma 5. Oral access to the airway for standard placement of a DLT or blocker
HistoryDetailed history regarding the quality of life preoperatively Respiratory mechanics All patients should have a baseline spirometry: FEV 1, FVC, MVV, RV/TLC FEV 1 % ( % of predicted volume corrected for age,gender and height). ppo FEV 1 % ( predicted post operative FEV 1 ) Calculated as ppoFEV1 % = preop FEV1 % (1-% functional lung tissue removed/100) ppo FEV1 % > 40% low risk ppoFEV1 % <40% major complication ppo FEV1 % <30% high risk
Lung parenchymal tests ABG parameter : PaO 2 < 60mm Hg PaCO 2 >45 mmHg ( warning indicator of increased risk, however resections are done with these figures nowadays) Most useful test : DL CO ppo DLco can be calculated like ppo FEV1 ppo DLco < 40 % increases respiratory and cardiac complications PREOP. FEV1 OR DLco < 20% Is UNACCEPTABLE and is the absolute MINIMAL value required. ( national emphysema treatment trial )
Laboratory exercise testing Gold standard Vo 2 max (maximum oxygen consumption) is the most useful predictor of post operative outcome. Vo 2 max < 15 ml/kg/min is unacceptable Vo 2 max >20 ml/kg/min has fewer complication EXPENSIVE Stair climbing tests 5 flights of stairs ~ V02 max >20 ml/kg/min 2 fight of stairs ~ Vo2 max ~ 12 ml/kg/min -- very high risk (climbing should be at patients own pace without stopping, 1 flight of stairs = 20 steps withs each step of 6 inches )
Six minute walk test(6MWT) < 610 m/ 2000 ft ------ Vo2 max< 15 ml/kg/min ~fall in SpO2 > 4% during exercise ( increased morbidity and mortality) ppo V02 max< 10 ml/kg/min is an absolute contraindication mortality rate is approximately 100% V-P scintigraphy Should be considerd for any patient of pneumonenctomy having a preop FEV1 &/or Dlco <80% performed at rest while FEV1 is a forced maneuver
Split lung function test These tests have not shown sufficient predictive value or validity for universal adoption and are hence not recommended any longer Replaced by spirometry/ DLco/ exercise tolerance & V/Q scaning.
Time CourseBeneficial Effects 12–24 hrDecreased CO and nicotine levels 48–72 hrCOHb levels normalized, ciliary function improves 1–2 wkDecreased sputum production 4–6 wkPFTs improve 6–8 wkImmune function and metabolism normalizes 8–12 wkDecreased overall postoperative morbidity and mortality
Mass effectsObstructive pneumonia,lung abscess, superior vena cava syndrome, tracheobronchial distortion, pancoast syndrome, recurrent laryngeal nerve or phrenic nerve palsy, chest wall or mediastinal extension Metabolic effect Lambert – Eaton syndrome, hypercalcemia, hyponatremia, cushing syndrome MetastasesParticularly to brain, bone, liver and adrenal MedicationsChemotherapy agents, pulmonary toxicity ( bleomycin,mitomycin C), cardiac toxicity(doxorubicin), renal toxicity ( cisplatin )
Initial assessmentFinal assessment 1. COPD patients : ABG, physiotherapy, bronchodilators 2. Assess exercise tolerance,estimate ppo FEV1, discuss post op. analgesia, discontinue smoking 3. Patients with ppo FEV1<40%:Dlco,V/Q scan,Vo2 max 4. Cancer patient: consider 4Ms 5. Increased renal risk : measure creatinine and BUN 1. Review initial assessment and test results. 2. Assess difficulty of lung isolation: chest Xray and CT scan. 3. Assess risk of hypoxemia during one lung ventilation
avoid inadvertent withdrawal of those drugs that are taken for concurrent medical conditions For surgeries like oesophageal reflux surgeries aspiration prophylaxis are routinely ordered preoperatively do not routinely order preoperative sedation or analgesia for pulmonary resection patients Mild sedation short-acting benzodiazepine is often given immediately before placement of invasive monitoring lines and catheters. an antisialagogue (e.g., glycopyrrolate) is useful to facilitate fiberoptic bronchoscopy It is a common practice to use short-term intravenous antibacterial prophylaxis
Oxygenation : significant desaturation( SpO2<90%) occurs in 1-10% of patients inspite of high FiO2 (1.0). PaO2 offers a better margin of safety then SpO2 Decreased initial PaO2 and rapid fall in PaO2 after initiation of OLV is a good indicator of subsequent desaturation. Useful to measure PaO2 before and 20 minutes after OLV Capnometry Less reliable then PaCO2 PaCO2-EtCO2 gradient increased Other components of minimum mandatory monitoring : BP,ECG,temperature
Conditions during thoracotomy in the lateral decubitus position when pulmonary artery (PA) catheter data may be inaccurate.
The majority of thoracic procedures are performed with the patient in the lateral position monitors will be placed and anesthesia will usually be induced with the patient in the supine position hypotension on turning the patient to or from the lateral position All lines and monitors will have to be secured during position change and their function reassessed after repositioning anesthesiologist should take responsibility for the head, neck, and airway during position change Endobronchial tube/blocker position and the adequacy of ventilation must be rechecked by auscultation and fiberoptic bronchoscopy after patient repositioning.
1. Dependent eye 2. Dependent ear pinna 3. Cervical spine in line with thoracic spine 4. Dependent arm: a. Brachial plexus b. Circulation 5. Nondependent arm : a. Brachial plexus b. Circulation
Dependent Arm (Compression Injuries) Arm directly under thorax Pressure on clavicle into retroclavicular space Cervical rib Caudal migration of thorax padding into the axilla Nondependent Arm (Stretch Injuries) Lateral flexion of cervical spine Excessive abduction of arm (>90%) Semiprone or semisupine repositioning after arm fixed to a support
Fluid Management for Pulmonary Resection Surgery 1. Total positive fluid balance in the first 24-hour perioperative period should not exceed 20 mL/kg. 2. For an average adult patient, crystalloid administration should be limited to < 3 L in the first 24 hours. 3. There should be no fluid administration for third space fluid losses during pulmonary resection. 4. Urine output > 0.5 mL/kg/hr is unnecessary. 5. If increased tissue perfusion is needed postoperatively, it is preferable to use invasive monitoring and inotropes rather than to cause fluid overload.
anesthetic technique should optimize the myocardial oxygen supply/demand Thoracic epidural anesthesia/analgesia is recommended high incidence of coexisting reactive airway disease, added airway manipulation by the DLT or bronchial blocker Thus, need anesthetic technique that decreases bronchial irritability, causes bronchodilation, and avoids release of histamine For intravenous induction of anesthesia either propofol or ketamine, & for maintenance of anesthesia, propofol and/or any of the volatile anesthetics are recommended
All of the volatile anesthetics inhibit HPV in a dose-dependent fashion : halothane > enflurane > isoflurane In doses less than or equal to 1 MAC, the modern volatile anesthetics depress HPV minimally Hence TIVA has no proven benefit against 1 MAC inhalational anesthesia
ParameterSuggestedGuidelines/ Exceptions Tidal volume5-6 mL/kg Maintain: Peak airway pressure < 35 cm H 2 O Plateau airway pressure < 25 cm H 2 O Positive end-expiratory pressure 5 cm H 2 O Patients with COPD: no added PEEP Respiratory rate12 breaths/min Maintain normal Paco 2 ; Pa-ETco 2 will usually increase 1-3 mm Hg during OLV Mode Volume or pressure controlled Pressure control for patients at risk of lung injury (e.g., bullae, pneumonectomy, post lung transplantation) Suggested ventilatory parameters for OLV
Therapies for Desaturation during One-Lung Ventilation Severe or precipitous desaturation: Resume two-lung ventilation (if possible). Gradual desaturation: 1. Ensure that delivered Fio 2 is 1.0. 2. Check position of double-lumen tube or blocker with fiberoptic bronchoscopy. 3. Ensure that cardiac output is optimal; decrease volatile anesthetics to < 1 MAC. 4. Apply a recruitment maneuver to the ventilated lung (this will transiently make the hypoxemia worse). 5. Apply PEEP 5 cm H 2 O to the ventilated lung (except in patients with emphysema). 6. Apply CPAP 1-2 cm H 2 O to the nonventilated lung (apply a recruitment maneuver to this lung immediately before CPAP). 7. Intermittent reinflation of the nonventilated lung 8. Partial ventilation techniques of the nonventilated lung: a. Oxygen insufflation b. High-frequency ventilation c. Lobar collapse (using a bronchial blocker) 9. Mechanical restriction of the blood flow to the nonventilated lung
leading cause of postoperative morbidity and mortality Acute respiratory failure after lung resection is defined as: acute onset of hypoxemia (Pa O 2 45 mm Hg use of postoperative mechanical ventilation for more than 24 hours reintubation for controlled ventilation after extubation incidence of respiratory failure after lung resection is between 2% and 18%