ANAESTHESIA FOR THORACOSCOPY, VATS, BAL,MEDIASTINOSCOPY AND ESOPHAGOSCOPY

BY- DR SUCHIT KHANDUJA MODERATOR- DR AJAY SOOD

MEDICAL THORACOSCOPY

HistoryThoracoscopy was introduced together with laparoscopy in 1910 by Hans-Christian Jacobaeus.

Jacobaeus initiated the therapeutic application of thoracoscopy for lysis of pleural adhesions

With the advent of anti-tuberculosis drugs, thoracoscopy was abandoned for several decades.

Recent technologic advances such as improved optical and video technology have revitalized the use of this procedure as a diagnostic and therapeutic tool.

History Excellent results of laparoscopic surgery and the tremendous advances in endoscopic technology stimulated many thoracic surgeons to develop minimally invasive techniques, which were termed therapeutic or surgical thoracoscopy, as well as video-controlled or video-thoracoscopic surgery, or video-assisted thoracic surgery (VATS).Pleuroscopy (medical thoracoscopy) is considered as a part of the field of interventional pulmonology.

INDICATIONS OF MEDICAL THORACOSCOPYPleuroscopyPleural effusions Staging of lung cancer Staging of diffuse malignant mesothelioma Pleurodesis by talc poudrage

ContraindicationsAbsolute:Size of free pleural space

TechniquesPleuroscopy is an invasive technique that should be used only when other, simpler methods do not provide the diagnosis.The technique is actually very similar to chest tube insertion by means of a trocar.There are two different techniques of diagnostic and therapeutic pleuroscopy.

TechniquesThe first method uses a single entry site, usually with a 9-mm trocar, for a thoracoscope with a working channel for accessory instruments and optical biopsy forceps that is employed under local anesthesia.In the other technique, as used by Jacobaeus for lysis of adhesions, two entry sites are used: one with a 7-mm trocar for the examination telescope and the other with a 5-mm trocar for accessory instruments, including the biopsy forceps. General anesthesia is preferred for above

EquipmentThe single-entry-site technique is usually done with a 9-mm diameter trocar and a cannula with valve. The two-entry-site technique uses a 7-mm trocar for the first site of entry, with appropriate telescopes and forceps, and similar accessory instruments. For the second site of entry, a 5-mm trocar is used.A, Trocar and cannula with valve. B, Single-incision thoracoscope (9 mm diameter). C, Biopsy forceps with straight optical device. D, Magnified view of optical device and forceps in the thoracoscope shaft ready for biopsy.

EquipmentSemirigid pleuroscope with biopsy forcepsIt has the advantage that the skills involved in operating the instrument are already familiar to the practicing bronchoscopist.Its disadvantages compared to rigid thoracoscopic instruments are the smaller biopsy specimens. However, the flexible tip allows very homogeneous distribution of talc on all pleural surfaces.

EquipmentThe procedure suite should be equipped with monopolar and, if possible, bipolar electrocoagulation as well as equipment for resuscitation and assisted ventilation, electrocardiography, blood pressure monitoring, defibrillator and as well as oxygen and vacuum generators.

PREOPERATIVE PREPARATIONRadiologic evaluation include P-A and lateral chest radiograph. Ultrasound for localization of the pleural fluid and for diagnosis of fibrinous membranes or adhesions in the pleural space.CT scan is not mandatory, but can be helpful in certain situations such as loculated empyema and localized lesions of the chest wall or diaphragm.ABGECGClinical laboratory tests

Pleuroscopic TechniqueThe site of introduction of the pleuroscope depends in part on the location of abnormalities to access and the location of potentially hazardous areas to avoid. The region of the diaphragm is unsuitable. The trocar is generally introduced in the lateral thoracic region between the mid- and anterior axillary line in the fourth to seventh intercostal space.

Area is prepared with cleansing agent

Local anesthesia is administered and after making a small skin incision, the trocar is advanced with a fairly forceful corkscrew motion until the detectable resistance of the internal thoracic fascia has been overcome. The cannula of the trocar should lie at least 0.5 cm within the pleural space.

Pleural effusions should be removed completely by using a suction tube that does not fully occlude the cannulaAfter complete removal of the effusion, or in cases without effusion, the optical device is introduced through the cannula, and the pleural space is then inspected.Biopsies of the pleura and, if needed, of the lungs, can be carried out most easily and safely by means of the lung biopsy forceps. Although a single site of entry is generally sufficient, a second site may be useful for biopsies or to perform coagulation

Pleuroscopic Technique

Anesthesia Pleuroscopy by the single-entry-site technique is usually done under local anesthesia with premedication, using an antianxiolytic, a narcotic, or both (e.g., midazolam and hydrocodone). Additional pain medication should be given during the procedure, as required.An excellent alternative is sedation by propofol with or without premedication. General anesthesia with intubation and ventilation is not necessary for pleuroscopy

ComplicationsMortality - 0.01-0.25 %

Morbidity:Desaturation during procedure ( LA) 7d)

VATS

Video-assisted Thoracic Surgery(VATS)VATS uses small incisions to perform therapeutic interventions in the chest without spreading the ribs.VATS requires an operating room, general anesthesia with single-lung ventilation, more than two (usually three) entry sites, and complex instruments. Overall, it is a more invasive and expensive technique with a higher risk than pleuroscopyIn experienced hands and in the proper setting, VATS is less invasive, is less expensive, and has a lower risk than open procedures.

IndicationsLung biopsyLobectomyDecorticationLung volume reduction surgeryPleura proceduresPleurectomy (pneumothorax)Drainage/decortication (empyema stage III)Mediastinal proceduresResection of mediastinal massThoracic lymphadenectomyThoracic duct ligationPericardial windowSympathectomyEsophageal proceduresExcision of cyst, benign tumorsEsophagectomyAnti-reflux procedures

General ProcedureThe trocar and the camera are placed in the midaxillary line in approximately the eighth intercostal space. Most of the surgeons use a reusable 5-mm trocar and a 30-degree, 5-mm thoracoscope. A 2-cm incision is made in about the sixth intercostal space in the mid-clavicular line. An additional incision is made in the fourth intercostal space in the midaxillary line.A variety of equipment is available for VATS procedures.

Basic instrumentation for VATSThree-chip endoscopic video camera and high-definition television monitorOperating thoracoscope (with 5-mm biopsy channel)Three standard-length ringed forcepsSuction-irrigation system 10 mm diameterEndoscopic hook cautery (5 mm) with trumpeted suctionStandard electrocautery unit with extended tip for application through intercostal access siteLandreneau Masher setBulbed syringe (60 ml)Standard Metzenbaum scissors (1012 in.)Standard University of Michigan Mixner clamp (1012 in.)Standard-sized and pediatric Yankour metal suckersStandard 28-French chest tubes (straight and right angled) and closed drainage system

ANAESTHETIC IMPLICATIONSThoracoscopic surgery can be performed under local, regional, or general anesthesia with two-lung ventilation or OLV. For minor diagnostic procedures VATS can be done in the awake patient. Intercostal nerve blocks performed at the level of the incision and two interspaces above and below provide adequate analgesia. Partial collapse of the lung on the side of surgery occurs when air enters the pleural cavity. When using local anesthesia with the patient awake, it is hazardous to insufflate gases under pressure into the hemithorax in an attempt to increase visualization of the pleural space. Changes in PaO2, PaCO2, and cardiac rhythm are usually minimal during the procedure when it is performed under local anesthesia and the patient is breathing spontaneously. It is recommended that a high FIO2 is delivered via a facemask to overcome the shunt due to the loss in lung volume caused by the unavoidable pneumothorax.

For most invasive procedures VATS is performed under general anesthesia with a DLT or a bronchial blocker to achieve OLV. Lung collapse will take longer when a bronchial blocker is used; if rapid lung collapse is needed, a DLT may be the preferred choice. If the procedure is short in duration and the lung needs to be deflated for only a brief period, blood gases are not routinely monitored during the procedure. However, for patients undergoing prolonged VATS procedures such as lobectomy or for patients with marginal pulmonary status, an arterial line and measurement of arterial blood gases is required. Paravertebral and intercostal blocks have been used with a single dose of local anesthetics and have been shown to reduce pain after thoracoscopic surgery for 6 hours

Contraindications and complications same as medical thoracoscopy

BRONCHALVEOLAR LAVAGE

BRONCHOALVEOLAR LAVAGE General indications:Non-resolving pneumoniaDiffuse lung infiltrates (interstitial and/or alveolar)Suspected alveolar hemorrhageQuantitative cultures for ventilator associated pneumoniaInfiltrates in an immunocompromised hostExclusion of diagnosable conditions by BAL, usually infectionResearch

BAL can be diagnostic in the appropriate clinical setting for:Alveolar hemorrhageMalignancies Lymphangitic carcinomatosisBronchoalveolar carcinomaOther malignanciesInfections PCPMycobacterialBacterialFungalViral

EquipmentFlexible bronchoscope/DLTSterile collection trapSuction tubingSterile salineVacuum sourceSyringeOptional 3 way stop-cockLidocaine 1-2%

Preparation and Anesthetic implicationsObtain informed consent.If an outpatient procedure, the patient should be accompanied by a person designated to drive the patient.BAL should be planned to be performed prior to any other bronchoscopic procedure.Review radiographs to determine ideal site of alveolar lavage. In diffuse infiltrates, the right middle lobe (RML) or the lingula in the supine patient is preferred.

Prepare bronchoscope/DLT, collection trap, and tubing. Prepare supplemental oxygen and monitoring equipment. ECG, pulse-oximetry, NIBPPremedicate with bronchodilators and/or warm the saline solution for those at risk for bronchospasm.Position patient, preferably in supine position when approaching RML or lingula.Apply monitors and supplemental oxygen.Sedation with a benzodiazepine and a narcotic will allow patient comfort and minimize cough reflex.

Radiologic imaging, CT, and ventilation-perfusion scans help to determine the most impaired lung, which will be lavaged first. General anesthesia is induced and maintained with intravenous infusions as for lung transplantation.

Airway management is with a left-sided DLT. Precise placement of the tube is confirmed by fiberoptic bronchoscopy Air-tight isolation is determined by monitoring inspired and expired tidal volumes with side-stream spirometry. Tube dislodgment and flooding of the nonlavaged lung is a major complication of this procedure.

Specifically during lavage of the left lung, the pressure of saline in the lung will tend to push the bronchial cuff of the DLT proximally. To prevent this it is recommended that the anesthesiologist maintain his or her hand on the DLT, securing it firmly at the patient's mouth, throughout the entire procedure. The pulmonary compliance of the ventilated lung needs to be continuously monitored to diagnose any liquid spillage from the lavage lung.

The patient is kept in the supine position during the procedure. To improve the effectiveness of the lavage, ventilation with FIO2 100% for a few minutes is initiated after induction to de-nitrogenate both lungs. OLV is instituted with the nonlavage lung. A disposable irrigation and drainage system is used to instill approximately 1L of warm normal saline (37C) into the lavage lung

The irrigating liquid is suspended 30cm above the patient's mid-chest level to the lavage lung. Thereafter, the saline is rapidly drained by gravity into a container positioned 60cm below or with the assistance of a small level of suction (

Chest physiotherapyis applied during the filling and the drainage phases. The use of flannel protects the patient's chest wall from trauma due to physiotherapy during the percussion. If the cumulative total of the instilled fluid volume exceeds the drainage volume by more than 1000mL a hydrothorax should be suspected

Oxygenation increases during the filling phase and decreases during the emptyingChanges are usually transient and well tolerated. Inflation of a pulmonary artery catheter balloon in the pulmonary artery of the lavage lung while adding nitric oxide to the ventilated lung or the use of ECMO to maintain oxygenation and prevent hypoxaemia.

Usually 10 to 15L is instilled and more than 90% is recovered, leaving a deficit of less than 10%. At the end of the procedure the lavaged lung is thoroughly suctionedA dose of furosemide (10mg) is administered to increase diuresis of absorbed saline. If the plan is to proceed to a lavage of the contralateral lung there is a period of at least 1 hour of two-lung ventilation.

After the procedure, after re-intubation with a single-lumen tracheal tube, inspection with fiberoptic bronchoscopy is performed for suctioning. Conventional ventilation with PEEP is continued, usually for less than 2 hours. Alveolar infiltrates seen on the chest radiography immediately after lavage normally clear within 24 hours. Observation in the intensive care unit for 24 hours is part of the routine procedure

Complications/Adverse eventsNo complications in up to 95%CoughTransient fever (2.5%)Transient chills and myalgiasTransient infiltrates in most (resolves in 24 hours)Bronchospasm (

ESOPHAGOSCOPY

ESOPHAGOSCOPY DIAGNOSTIC INDICATIONSHistory of functional disease of esophagusRadiological evidence of disease of esopagusSuspected foreign body of esophagusAsessment of caustic ingestion

THERAPEUTIC INDICATIONSRemoval of foreign bodiesDilation of cardia and division of divericulumInjection in varices

CONTRAINDICATIONUncorrected medical disorder

For rigid esophagoscopy severe kyphoscoliotic disorder or cervical spondylitis

POSITIONINGPositioning is same as that for laryngoscopy and bronchoscopyTable must have a flexible head restOn occasion shoulder role may be heplful but pts head need to be extended during esophagoscopy

INSTRUMENTSA no. of flexible scopes are available which allow superior visualisationRigid esophagoscope may be round or oval(hollinger or jesberg) with or without telescope.

ANAESTHETIC IMPLICATIONSPreoperative sedation may be neededWith a flexible scope local anaesthesia is used with concomitant sedationFor children GA is usedFor rigid esophagoscopy GA is preferredForeign body removal is done under GAAll such pts must be considered to be full stomach

Rapid sequence anaesthesia preferred in all such pts.Once airway is secured higher degree of inhalational anaesthetic with muscle relaxation given to ensure minimal movement during procedureGreater chances of extubation because of neck extension

TechniqueCan be done under LA/GAIf GA is used intubation is first performedEsophagoscopy canbe performed without laryngoscopyThe scope is passed along the post pharangeal wall to the level of arytenoidsNarrow horizontal slit seen posterior to larynx ,leading edge of esophagoscope passed into the slit and cricoid lifted anteriorly.Scope then passed into lumen of esopagus

Once lumen of esophagus entered further head extension may be needed.The mucosa is identified for any pathological changesScope is advanced gently without excessive thrustingCare must be given to keep the telescope within esophagoscope

MEDIASTINOSCOPY

MEDIASTINOSCOPY Mediastinoscopyis really asurgical procedurewhich allowsphysiciansto viewregions ofthe mediastinum. INDICATIONSDiagnosticmethod ofchoice fordetectinglymphoma, including Hodgkin's diseaseDiagnosisof sarcoidosisand thestaging oflung cancercan also beattainedthrough mediastinoscopyAllowsphysicianto observeanddraw outa samplefrom thenodes for morestudy.Most reliable techniques for establishing histologic diagnosis in patients with superior vena cava obstruction

ContraindicationsPrevious mediastinoscopy is a relatively strong contraindication to a repeat procedure Superior vena cava (SVC) syndrome increases the risk of bleeding from distended veins and is a relative contraindication. Other relative contraindications include Severe tracheal deviation Cerebrovascular diseaseSevere cervical spine disease with limited neck extensionPrevious chest radiotherapy Thoracic aortic aneurysm

TECHNIQUEThe majority of mediastinoscopies are performed via the cervical approach, entering the mediastinum through a 3-cm incision in the suprasternal notch. A dissection is made between the left innominate vein and the sternum creating a tunnel in the fascial layers. The mediastinoscope is then inserted anterior to the aortic arch. The less commonly performed anterior approach is through the second intercostal space, lateral to the sternal border; this is used to inspect the lower mediastinum.

INVESTIGATIONSShould include chest X-ray, and CT scan aimed at evaluating the location of the tumour, its relation to adjoining structures, and the degree of tracheal compression. Pulmonary function tests are useful in detecting the severity of pre-existing lung disease and effects of mediastinal mass. Flowvolume curves should be obtained in the upright and supine position to evaluate functional impairment and ascertain the presence of obstruction. Both inspiratory and expiratory flows are usually reduced in the presence of an intrathoracic mass. A disproportionate decrease in maximal expiratory flow should raise suspicion of tracheomalacia.

Premedication with Anaesthetic managementA short-acting benzodiazepine may be prescribed to decrease anxiety; however, sedative drugs should be avoided if tracheal obstruction is suspected. Large bore intravenous cannulae should be inserted and cross-matched blood should be available If the patient is asymptomatic, preoxygenation followed by intravenous induction of anaesthesia can be performed. In the presence of respiratory obstruction, an awake intubation under local anaesthetic is the technique of choice.

This allows the entire anaesthetic and surgical team to view the exact level of obstruction and the endotracheal tube is passed distal to obstruction. In a more distal obstruction (carinal level), a rigid bronchoscope should be available for low-frequency jet ventilation. An inhalation induction may be used, followed by intubation of the trachea under deep anaesthesia. The patient is placed in a 20 head-up position to reduce venous congestion. Surgical access is improved by resting the shoulders on a sandbag and the head on a head ring.

An intravenous anaesthetic agent, inhalational anaesthetic agent, or both, together with a neuromuscular blocking agent and a bolus or continuous infusion of a short-acting opioid will allow an adequate level of anaesthesia and rapid postoperative recovery. Ventilation of both lungs through a single-lumen endotracheal tube is usually adequate A reinforced tube is preferred to minimize the risk of the tube kinking during surgery. With a long-standing mass, fibreoptic endoscopy should be performed prior to extubation to rule out tracheomalacia.

Patients should only be extubated after full recovery of reflexes and neuromuscular function;A short period of postoperative ventilation may be requiredLocal anaesthetic infiltration of the wound, superficial cervical plexus and intercostal nerve blocks aid postoperative analgesia. Postoperatively, a chest X-ray should be taken in all patients in the recovery room to exclude pneumothorax. Patients should be observed specifically for dyspnoea and stridor.

MonitoringInvasive arterial blood pressure monitoring is preferred for the early detection of reflex arrhythmias and compression of major vessels with mediastinoscope. This should preferably be sited in the right arm for detection of brachiocephalic compressionAlternatively, the pulse oximeter probe should be placed on the right hand. Neuromuscular monitoring is mandatory in patients with myasthenia gravis and EatonLambert syndrome. The ventilator pressure gauge should also be observed to note any acute increase in airway pressure, which indicates tracheal or bronchial compression by the mediastinoscope.

Risks Hemorrhage Pneumothorax Recurrent laryngeal nerve injury, causing hoarseness Infection Tumor implantationwithin thewound Phrenic nerve injury Esophageal injury Chylothorax Air embolism Transient hemiparesis

THANX!!

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