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University College of Medical Sciences

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1 University College of Medical Sciences
Principle of thoracic anesthesia with determinants of operability for resection, One lung anesthesia Dr. Rajesh Kumar University College of Medical Sciences & GTB Hospital, Delhi

2 Objectives Indication/contraindication of OLV
Physiological changes of OLV Lung separation techniques and equipments

3 Introduction 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

4 Indication 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

5 Indication (continued)
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

6 Physiology of the LDP Upright position LDP, lateral decubitus position

7 Physiology of LDP Distribution of ventilation

8 Shunt and OLV Physiological (postpulmonary) shunt
About 2-5% CO, Accounting for normal A-aD02, 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

9 Two-lung Ventilation and OLV

10 OLV and shunt fraction with and without anesthesia

11 Physiology of OLV 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.

12 HPV 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

13 Factors Affecting Regional HPV
HPV is inhibited by: volatile anesthetics (not N20), vasodilators (NTG, SNP, dobutamine, many ß2-agonist), increased PVR and hypocapnia PEEP, vasoconstrictor drugs (preferentially constrict normoxic lung vessels)

14 Methods of OLV 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

15 DLT 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)


17 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

18 Method of insertion 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

19 Confirming position of DLT
Alternately blocking the tracheal and bronchial lumen and checking for the air entry. With the help of fiberoptic bronchoscopy Chest –x ray

20 Confirming Position of DLT………

21 Selection of DLT based on adult patient sex and height
Height(cm) Size(Fr) Female <160 (63 inches) 35 >160 37 Male <170 (67 inches) 39 >170 41

22 Right sided DLT Margin of safety is low :
1. Rt. Upper lobe bronchus is short 2. Rt. u/l bronchus originates at a distance of cm from the carina Fewer indications Doughnut shaped cuff Additional opening for the ventilation of right upper lobe.

23 Indications for a right sided DLT
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

24 Left DLT 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

25 Univent Tube... 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

26 Arndt Endobronchial Blocker set
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

27 Other Methods of OLV 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

28 Comparision of lung isolationtechniques
OPTIONS ADVANTAGES DISADVANTAGES Double lumen tube Direct laryngoscopy Via tube exchanger 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

29 Options Advantages Disadvantages Univent tube Same as BBs Less repositioning compared with BBs ETT portion has higher airflow resistance than regular ETT ETT portion has larger diameter than regular ETT Endobronchial tube Like 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

30 Difficult airway and 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

31 Approach to difficult airway
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

32 In a tracheostomised patient
Insertion of a SLT f/b an independent bronchial blocker Use of a disposable cuffed tracheostomy cannula with an independent bb passed coaxially Replacement of the tracheostomy canula with a short DLT such as NARUKE DLT Placement of a small DLT through tracheostomy stoma Oral access to the airway for standard placement of a DLT or blocker

33 objectives Preanesthetic assessment Anesthetic management
Postoperative management

34 Fundamentals to anesthetic management of thoracic procedures
Lung isolation to facilitate surgical access Management of one lung anesthesia

35 Preoperative evaluation done in two disjoint phases:
The initial clinical assessment The final assessment on the day of admission

36 Primary function of PAC
To identify patients at elevated risk, To stratify perioperative management and focus resources Feasibility of lung resection in a high risk patient

37 Perioperative complications (overall mortality 3-4%)
incidence Respiratory (atelectasis, pneumonia,respiratory failure) 15-20 % Cardiovascular (arrhythmia and ischemia) 10-15%

38 Assessment of respiratory functions
History Detailed history regarding the quality of life preoperatively Respiratory mechanics All patients should have a baseline spirometry: FEV1, FVC, MVV, RV/TLC FEV1% ( % of predicted volume corrected for age,gender and height). ppo FEV1 % ( predicted post operative FEV1 ) 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


40 Assessment of respiratory functions continued……………
Lung parenchymal tests ABG parameter : PaO2 < 60mm Hg PaCO2 >45 mmHg ( warning indicator of increased risk, however resections are done with these figures nowadays) Most useful test : DLCO 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 )

41 Assessment of respiratory functions continues……… cardiopulmonary interactions (most important assessment of respiratory function) Laboratory exercise testing Gold standard Vo2 max (maximum oxygen consumption) is the most useful predictor of post operative outcome. Vo2 max < 15 ml/kg/min is unacceptable Vo2 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 )

42 Assessment of repiratory functions continues……………
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

43 Assessment of repiratory functions continued……………
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.

44 The three legged stool of pre thoracotomy respiratory assessment
Respiratory mechanics FEV1(ppo>40%) MVV, RV/TLC, FVC Cardiopulmonary reserve Vo2 max >15ml/kg/min Stair climbing>2 flight 6MWT>610m/2000ft Exercise SpO2 < 4 % Lung parenchymal function Dlco (ppo >40%) PaO2 >60 PaCO2 <45

45 Concomitant medical conditions
cardiovascular Ischemia : intermediate risk surgery 5% incidence post thoracotomy peaks on 2 and 3rd post op day ACC/AHA guidelines to be followed Arrhythmias Right ventricular dysfunction Renal dysfunction Perioperative mortality is 19% in pt. developing deranged KFT in periop. Period as against 0% in those having normal KFT Increased risk in pt. having h/o renal impairment use of diuretic use of NSAIDS Hence I/op fluid management and intensive perioperative fluid management is essential Age Rate of respiratory complication doubles(40%) and cardiac complications (40%) triples in elderly

46 Concomitant medical conditions continues…….
Problems in a COPD patient Respiratory drive, CO2 retainers, Increased role of HPV Nocturnal hpoxemia because of rapid shallow breathing in a REM sleep Right ventricular dysfunction Bullae Flow limitation : stage I :FEV!>50% no significant dyspnoea ,hypoxemia or hypercapnia Stage III :FEV1 <35% --life expectancy <3 years post thoracotomy

47 Beneficial effects of smoking cessation and time course
12–24 hr Decreased CO and nicotine levels 48–72 hr COHb levels normalized, ciliary function improves 1–2 wk Decreased sputum production 4–6 wk PFTs improve 6–8 wk Immune function and metabolism normalizes 8–12 wk Decreased overall postoperative morbidity and mortality

48 Anesthetic considerations in lung cancer patients (“the 4 Ms” )
Mass effects Obstructive 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 Metastases Particularly to brain, bone , liver and adrenal Medications Chemotherapy agents , pulmonary toxicity ( bleomycin,mitomycin C), cardiac toxicity(doxorubicin), renal toxicity ( cisplatin )

49 Preoperative therapy for COPD

50 To discuss post op analgesia
the risks and benefits of the various forms of post-thoracotomy analgesia should be explained to the patient Potential contraindications such as coagulation problems, sepsis, or neurologic disorders should be determined American Society of Regional Anesthesia (ASRA) an interval of 2 to 4 hours before or 1 hour after catheter placement for prophylactic heparin administration. an interval of 12 to 24 hours before and 24 hours after catheter placement is recommended for LMWH

51 Think about post thoracotomy anesthetic management (based on ppo FEV1%)
>40% Extubate in the OR Patient AWaC (alert ,warm and comfortable) 30-40% Extubation on the basis of Exercise tolerance,Dlco,V/Q scan, associated diseases <30% Staged weaning Consider extubation if >20% + thoracic epidural analgesia

52 Summarise preoperative assesment
Initial assessment Final assessment COPD patients : ABG, physiotherapy , bronchodilators Assess exercise tolerance,estimate ppo FEV1, discuss post op. analgesia, discontinue smoking Patients with ppo FEV1<40%:Dlco,V/Q scan,Vo2 max Cancer patient: consider 4Ms Increased renal risk : measure creatinine and BUN Review initial assessment and test results. Assess difficulty of lung isolation: chest Xray and CT scan. Assess risk of hypoxemia during one lung ventilation

53 Increased risk of hypoxemia
High percentage of ventilation or perfusion to the operative lung preoperatively Poor PaO2 during two-lung ventilation particularly in the lateral position intraoperatively Right sided thoracotomy Normal preoperative spirometry or restrictive lung disease Supine position during OLV

54 Premedication 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

55 Intraoperative monitoring
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

56 Invasive monitoring Arterial line:Surgical compression of heart & great vessels l/t hypotension CVP : non reliable , useful postoperatively Pulmonary artery catheters: less reliable for OLV unsurety about the location of the tip signficant u/l differences in lung perfusion. complications Continuous spirometry monitoring of inspired and expired volume  auto-PEEP aids in assessing and managing pulmonary air leak during pulmonary resection Transesophageal echocardiography :continuous real time monitoring ofmyocardial function and preload Potential indication: hemodynamic instability,pericardial effusion,cardiac involvement by tumour,air emboli,pulmonary thromboendarterectomy, thoracic trauma,lung transplantation. Difficult in pt. having esophageal pathology,

57 Conditions during thoracotomy in the lateral decubitus position when pulmonary artery (PA) catheter data may be inaccurate.

58 Positioning 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.

59 “Head-to-toe” survey for neurovascular injury after position change
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

60 Factors Contributing to Brachial Plexus Injury in the Lateral Position
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

61 Anesthetic management
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.

62 Use of nitrous oxide use of N2O/O2 mixtures is associated with a higher incidence of post-thoracotomy radiographic atelectasis (51%) in the dependent lung than when air/oxygen mixtures are used (24%). also tends to increase pulmonary artery pressures in patients who have pulmonary hypertension N2O inhibits HPV N2O is contraindicated in patients with blebs or bullae N2O is usually avoided during thoracic anesthesia

63 Temperature heat loss from the open hemithorax Most of the body's physiologic functions, including HPV, are inhibited during hypothermia particularly a problem at the extremes of the age spectrum. Increasing the ambient room temperature, fluid warmers, and the use of lower- or upper-body forced-air patient warmers (or both)

64 Cardiovascular and Respiratory goals
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

65 Choice of Anesthetic 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

66 Suggested ventilatory parameters for OLV
Guidelines/ Exceptions Tidal volume 5-6 mL/kg Maintain:    Peak airway pressure < 35 cm H2O Plateau airway pressure < 25 cm H2O Positive end-expiratory pressure 5 cm H2O Patients with COPD: no added PEEP Respiratory rate 12 breaths/min Maintain normal Paco2; Pa-ETco2 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)

67 Therapies for Desaturation during One-Lung Ventilation
Severe or precipitous desaturation: Resume two-lung ventilation (if possible). Gradual desaturation:    1.    Ensure that delivered Fio2 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 H2O to the ventilated lung (except in patients with emphysema).    6.    Apply CPAP 1-2 cm H2O 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

68 Post operative complications Early major
Respiratory failure cardiac herniation torsion of a remaining lobe after lobectomy dehiscence of a bronchial stump hemorrhage from a major vessel Where

69 Post operative respiratory failure
leading cause of postoperative morbidity and mortality Acute respiratory failure after lung resection is defined as: acute onset of hypoxemia (Pao2 < 60 mm Hg) or hypercapnia (Paco2 > 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%

70 To minimise pulmonary complications postoperatively
thoracic epidural analgesia : prevention of atelectasis and secondary infections better preservation of the functional residual volume efficient mucociliary clearance alleviation of the inhibiting reflexes acting on the diaphragm Chest physiotherapy, incentive spirometry, and early ambulation are crucial provide better oxygenation, treat infection, and provide vital organ support without further damaging the lungs.

71 multiple sensory afferents :
Post operative analgesia multiple sensory afferents : incision (intercostal nerves T4-T6), chest drains (intercostal nerves T7-T8), mediastinal pleura (vagus nerve, CN X), central diaphragmatic pleura (phrenic nerve, C3-C5), ipsilateral shoulder (brachial plexus). Hence there is no one analgesic technique that can block all these various pain afferents, so analgesia should be multimodal. The ideal post-thoracotomy analgesic technique will include three classes of drugs: opioids, anti-inflammatory agents, and local anesthetics.

72 Post op analgesia continues…
Systemic Analgesia: Opioids:effective in controlling background pain but the acute pain component associated with cough or movement requires plasma levels that produce sedation and hypoventilation NSAIDS :reduce opioid consumption more than 30%.particularly useful treating the ipsilateral shoulder pain Ketamine: less respiratory deppression Dexmedetomidine: described as an useful adjunct Local Anesthetics/Nerve Blocks: Intercostal nerve blocks Interpleural blocks Epidural analgesia

73 Thank you

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