Elective spine surgeries

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Elective spine surgeries

  1. 1. By: Siti Mohaini Anora bt IsmailModerator: Dr. Laila Mukmin
  2. 2.  Anaesthesia for major spinal surgery, such as spinal stabilization following trauma or neoplastic disease, or for correction of scoliosis, presents a number of challenges Commonly have preop. co-morbid conditions eg serious CVS & resp. impairment Airway management may be difficult
  3. 3. Mainly present with one of 5 pathologies: Trauma (eg unstable vertebral fracture) Infection (vertebral abscess) Malignancy (metastatic/primary dz with spinal instability, pain & neurological compromise) Congenital/idiopathic (example scoliosis) or Degenerative disease
  4. 4.  Neurological dysfunction (compression) Structural instability (abnormal displacement) Pathologic lesions (tumor / infection) Deformity (abnormal alignment) Pain (spinal column/discogenic/facetogenic)
  5. 5.  Patient‟smedical condition Surgical procedures – duration & surgical approachAirway Evaluation Mallampati Classification & various radiological predictors of difficult intubation & range of motion of the neckpain or other neurological symptoms during manipulation
  6. 6. Pulmonary Evaluation patient at risk of pulmonary dysfunction corrective surgeries (scoliosis) old age (degenerative spine diseases) acute fracture of cervical spine require special anaesthetic technique like one lung ventilation
  7. 7. Cardiac Evaluation Cardiac function m/be compromised by underlying medical conditions, neuromuscular disorder , rheumatoid arthritis , high cervical cord injuryNeurologic Evaluation Careful documentation of preexisting neurological deficit is essential Extent of neurological dysfunction may dictate intubation technique & choice of anesthetic agents
  8. 8. Haematological evaluation Many pts with spine pathology will have been taking some NSAIDs for analgesia Proper coagulation profile has to be ordered 1 author suggest to stop NSAIDs at least 10 days before elective surgeries (Samantaray 2006)Premedication Depends on haemodynamic stability and neurological status of patient
  9. 9. Minimum Ix Optional IxAirway •Cervical spine lateral x-rays with •CT scan flexion/extension views (for pts with rheumatoid arthritis) •Plain CXRResp. system •Arterial blood gas analysis •Pulmonary function tests •Pulmonary diffusion capacity (bronchodilator •Spirometry (FEV1, FVC) •reversibility) •Pulmonary diffusion capacityCVS •ECG •Dobutamine-stress •Echocardiography echocardiograph •Dypiridamole/thallium scintigraphyBlood tests •Full blood count •LFT •Clotting profile •Blood cross match •Urea, electrolytes •Albumin, calcium (neoplastic disease)
  10. 10.  Standard monitoring :  ECG  NIBP  Pulse oximetry  Capnograph  Temperature
  11. 11.  Special monitoring  for long procedure with potential for large volume shift, risk of venous air embolism & pts who have complicated medical hx, haemodynamic instability (spinal shock) or in procedures where special anesthetic techniques are planned like deliberate hypotension, endoscopic surgeries  Invasive BP, CVP, urine output  Swan Ganz cathetersevere cardiac or resp dz
  12. 12.  Specific monitoring  Neurologic monitoring procedures that may compromise the integrity of the spinal cord (SC): direct SC/ nerve damage during instrumentation, distraction injury or reduced SC perfusion resulting in ischemia  Spinal fusion, removal of SC tumors & vascular lesion are at more risk  Somatosensory Evoked Potential (SSEP)  Motor Evoked Potential (MEP)  Wake up test ~ adjunct (reliable)  Electromyographic monitoring (EMG)
  13. 13. MEP SSEPDorsal /Posterior SSEP MEP Ventral / Anterior
  14. 14.  To detect neurological injury and prevent devastating, irreversible damage For most, loss of motor worse than loss of sensory
  15. 15.  Spinal instrumentation Scoliosis correction Spinal cord operations Aortic surgery
  16. 16.  Stimulate a peripheral nerve often post tibial nerve Detect a response with epidural or scalp electrodes The evoked potentials are averaged more than 2 to 3 mins to eliminate background noise then displayed as voltage against time Nerve injury m/be indicated by decreased amplitude or increased latency
  17. 17.  Transcranial electrical impulses stimulate the motor cortex Resulting signal detected with epidural electrodes or as compound muscle action potentials (CMAPs) Complement with MEP when risk of spinal artery injury – anterior approach – ascending tract will be intact
  18. 18.  Provides snapshot of SC motor function Surgery is stopped Volatile/anesthetic agent switched off & emergence allowed Pt is asked to move their feet If can move, anaesthesia recommenced Assistance is needed to prevent pt movement which may cause accidental extubation or loss of vascular cannulae In the event of new paraplegia, all implants should be removed, hypotension & anaemia corrected & a course of high dose methylprednisolone commenced
  19. 19.  Incidenceof motor deficit or paraplegia after surgery to correct scoliosis:  Absence of SC monitoring : 3.7 – 6.9%  With intraop. monitoring : 0.5%  American Academy of Neurology: “considerable evidence favours the use of monitoring as a safe & efficacious tool in clinical situations where there is a significant nervous syst risk, provided its limitations are appreciated”  It is now considered mandatory to monitor SC function for these types of procedures  Raw et al, BJA 2003; 91: 886-904
  20. 20.  Major prob: maintenance of basic CVS monitoring techniques during positioning of pt Represent a stress to circulatory integrity & it is very difficult to prevent an almost total monitoring “blackout” as anesthetized pts are turned from the supine to prone position (most frequently used position) Particular attention on neck, arms, eyes to protect pressure-sensitive areas
  21. 21.  Regardless of how well positioned at start of procedure, on-going vigilance with regard to position is essential because pt situation may change after movement during wakeup test or manipulation of the operating table
  22. 22. Prone Positioner C-Shaped Face PieceHorseshoe Head Rest Mayfield Tongs
  23. 23.  Restriction of  Obstruction of Inf diaphragm Vena Cava  by abdominal contents  Decreases preload  and weight of pt against  Increases perivertebral thorax venous pressure Create restrictive  (pronemay improve defect oxygenation when Increased peak abdomen hangs free- inspiratory pressure (barotrauma) chest roll or frame)
  24. 24. Complication StrategyETT •Reinforced tubeobstruction/malpositionDirect pressure injury •Mayfield head frame •Ensure eyes, chin, nose are free from contact with any surface; check vigilantly •Pad all pressure points •Place breasts neutrally or medially •Keep male genitalia free of compression from bolsters or thighsIncreased •Allow for chest excursion and free abdominal movement by usingthoracic/abdominal chest & thigh rolls and/or special mattress for OR tablepressurePeripheral nerve injury •Avoid positions known to cause pain or paresthesia when pt is awake •Pad axillary and ulnar neurovascular bundles •Arms at sides when turning supine to prone •Consider use of SSEP and MEP to monitor for brachial plexus ischemia •Shoulder abduction < 90° and elbows placed in flexion
  25. 25. Complication StrategySwelling/dependent •Judicious use of crystalloids for fluid replacementedema of the tongue and •Check for ETT cuff leak prior to extubationoropharynxVascular occlusion •Avoid extremes of cervical range of motion •Watch for signs of jugular venous outflow obstruction
  26. 26.  Frame based table Allows abdomen and chest to hang freely May allow 180 degree rotation
  27. 27.  Maintains flexed position for spinal surgery Intrabdominal pressure may be increased if supporting pads are not properly placed
  28. 28.  Brachial plexus may be stretched Ulnar nerve not properly padded Eye damage from pressure Nose pressure Excessive compression to inferior vena cava (minimized by padding under inf iliac spine & chest rolls)
  29. 29.  Aim: to maintain a stable anaesthetic depth allowing for intraoperative neurophysiological monitoring Can be achieved with various techniques Anaesthetic technique impacts upon SC monitoring Volatile agents, propofol & nitrous oxide all depress SSEP and MEP Opioids have little effect NMB agents may reduce background noise when using SSEP but a profound block will prevent CMAP (Compound ms action potentials) Decrease in BP & Temp may also depress signals
  30. 30.  Any standard technique is acceptable Consider wire reinforced tube to avoid kinking and occlusion for prone, allows maximal banding to remove it from surgical field and prevent compression from retractor during cervical surgical procedures
  31. 31.  Cervical spine surgery require special consideration for airway management High incidence of difficult airway 20% grade 3-4 glottic visualization Rheumatoid dz: 48% difficult intubation Cervical fracture: 23% Cervical tumor: 24% Other predictor of difficult intubation include:  Upper vs lower C-spine dz  Presence of external or internal fixation devices
  32. 32.  Risk of neurologic injury is more when endotracheal intubation is attempted in patients suffering from C-spine dz Various studies have been made for evaluating optimal techniques for intubating patients at risk for cervical spine injury No single technique has been proved to be superior than the other Aware that there is risk of SC injury with laryngoscopy Recognize the increased probability of encountering a difficult a/way Attention to minimizing motion of the C-spine
  33. 33.  The adult cervical spine below C2 is unstable or on the brink of instability when one of the following conditions are met:  (i) all the anterior or all the posterior elements are destroyed;  (ii) there is >3.5 mm horizontal displacement of one vertebra in relation to an adjacent one on a lateral x- ray; or  (iii) there is more than 11° of rotation of one vertebra to an adjacent one Above level C2, eg of unstable injuries include:  disruption of the transverse lig. of atlas (distance >3 mm in adults betw. post. corpus ant. arch of C1 & ant. border of odontoid process  Jefferson burst fracture of the atlas following axial loading (causes atlantoaxial instability
  34. 34.  StandardN2O-opioid-based technique with NMB agent and low dose inhalational agent supplementation (Samantaray) Maintenance dose of anesthetics is altered – may have altered pharmacokinetics due to:  Muscle wasting  Decreased serum albumin  Eg. Suxamethonium contraindicated in muscular dystrophy – risk of rhabdomyolysis, hyperK, cardiac arrest
  35. 35.  Pt at high risk for neurologic injury intraop m/be managed with either  Induced hypertension  Maintenance of systemic BP within 10-20% of preop values Some centers utilize neurologic monitoring during placements of patients in the operative position to prevent position related injury Type, duration and extent of surgery may guide the approach to fluid administration & replacement  Avoid dextrose containing solution risk of worsening neurosurgical outcome in the presence of hyperglycemia during SC ischemia
  36. 36.  Surgical procedures involving significant bone work at multiple levels may be a/w large intraop bld loss & higher requirement for transfusion of bld and bld products Strategies to reduce @ remove risk of allogeneic transfusion:  Preop autologous donation  Acute normovolemic hemodilution  Perioperative cell salvage techniques  Deliberate hypotension  Pharmacologic interventions; tranexamic acid
  37. 37.  Complexity & extent of surgery, operative time, pt‟s co-existing dzs Bld loss/ transfusions Complications that occurred during or immediately after surgery Some may need post-op care in ICU Adequacy of a/way after ETT removal Leave ETT in place until fully awake, respond to command & able to manage own a/way Some leave ETT in place and spray lidocaine down trachea to prevent or minimize coughing or bucking on ETT for about 15-30 mins Consider inserting an a/way exchange catheter through ETT before removal in case need of immediate reinsertion of ETT if a/way obstruction from early/delayed swelling, bleeding or haematoma Cuff-leak test, if any uncertainty to perform flexible fibreoptic Spirometer on modern anesthesia machines can also be used to quantify leakage; expired-inspired vol
  38. 38. Defer extubation Consider extubationInability to open eyes & not obeying Awake & obey commandcommandsAgitated or combative Regular spontaneous breathingPoor resp. effortsO2 sat <94% O2 sat >94%Hypercarbic (PaCO2 >50) Normocapnic (30<PaCO2<50mmHg)Hemodynamic unstable Hemodynamic stableHypothermic (<36°) Normothermic Neuromuscular blockade completely reversed (TOF>90%, sustained head lift & strong hand grip)Operating time >10 hrs Operating time <10hrsBlood transfusion >4 units Blood transfusion <4 unitsEvidence of facial edema & macroglossia-ve cuff-leak test +ve cuff-leak testEvidence of pharyngeal & laryngeal edema No evidence of pharyngeal & laryngealon flexible fibreoptic bronchoscopy edema on flexible bronchoscopy Table 50.1 Criteria for extubation following complex spine surgery in prone position, Case Studies in Neuroanesthesia and Neurocritical Care, George A. Mashour & Ehab Farag, page 162
  39. 39.  Individualized for each patient To consider preop status, surgical procedures, intraop cx & pain tolerance Good post-op analgesia LA, opioid in epidural space before closing PCA Oral/ rectal analgesics
  40. 40. Early Fluid volume deficit Neurologic injury or deficit Dural tear with cerebral spinal fluid leakage Anemia Urinary retention Ileus Atelectasis/ pneumonia Venous thrombosis Specific to anterior cervical proedures: dysphagia, hoarseness, a/way obstruction from oedema
  41. 41. Late Skin breakdown Wound infection Spinal instability (after wide lumbar decompressive procedures not accompanied by fusion) Hardware failure Pseudoarthrosis Epidural fibrosis Transitional syndrome Arachnoiditis
  42. 42.  Perioperative vision loss (72% of perioperative vision loss reported are d/t spine surgery in prone position) perioperative ischemic optic neuropathy rare (3/10 000) Central retinal artery or vein occlusion Occipital lobe infarct Corneal abrasion most common eye injury after spine surgery (rarely leads to permanent vision problems)
  43. 43. Ischaemic Optic Central Retinal Artery Neuropathy (ION) Occlusion (CRAO)Etiology Intraop ↓ BP Direct external pressure Prolonged surgery Emboli ↑ Blood loss ↑ Crystalloid infusionMechanism Ischaemia ↓ Ocular perfusion pressure Orbital edema → stretch and compression of ONClinical Painless PainlessFeatures Bilateral Unilateral ↓ Light perception Periorbital swelling or ↓ Visual fields echymosis
  44. 44.  Lat. curvature & rotation of the thoraco- lumbar vertebrae with a resulting rib cage deformity Idiopathic @ secondary to neuromuscular dz, infection, tumor or injury Cobb Angle > 10° considered abnormal Surgery indicated when >40° Restrictive lung defect & dyspnoea on Cobb Angle exercise: > 65° Resp. failure, pulm. HPT, Rt heart failure: >100°
  45. 45.  Lat. curvature & rotational deformity of the thoraco- lumbar vertebrae with a resulting rib cage deformity occurs in up to 4% of the population Most cases idiopathic (70%) with male:female ratio of 1:4 Idiopathic/secondary to neuromusc. dz, infection, tumor or injury Cobb Angle > 10° considered abnormal Surgery: Cobb angle >50° in the thoracic, or >40° in the lumbar spine Restrictive lung defect & dyspnoea on exercise: > 65° Resp. failure, pulm. HPT, Rt heart failure: >100°
  46. 46. Classification of scoliosis aetiology – taken from BJA CEACCP 2006;6:1;13-16Idiopathic (70%) Early onset (infantile) Late onset (juvenile)Neuromuscular (15%) Crebral palsy Myopathies Poliomyelitis Syringomyelia Friedreich‟s ataxiaCongenital Vertebral anomalies Rib anomalies Spinal dyraphismTraumatic Vertebral fractures Radiation SurgerySyndromes Marfan‟s Rheumatoid arthritis Osteogenesis imperfecta Mucopolysaccharide disorders NeurofibromatosisNeoplastic Primary tumours Secondary tumoursInfection Tuberculosis Osteomyelitis
  47. 47.  Surgery may slow the decline in resp. fx & improve QOL by improving posture & helping nursing care Pts should be offered stabilization before the cardio-resp. dysfx prevents surgery Surgery aim to correct curve & fuse the spine, improving posture & halting the progression of pulm. dysfx Approach: posterior, anterior or combined, recent – thoracoscopy Left untreated, idiopathic scoliosis rapidly progresses & is often fatal by the 4th/5th decade of liferesult of pulm. HPT, right vent. failure, or resp. failure
  48. 48.  Most commonly used Skin & supraspinous lig. are incised & paraspinal ms reflected The vertebral laminae are then decorticated, facet joints destroyed & spinous processes removed Bone graft is packed over the raw decorticated surfaces & stainless steel rods are used to correct the deformity & provide stability for bony fusion (secured with pedicle screws or laminar hooks)
  49. 49.  Large thoraco-abdominal incision Exposure of vertebral bodies & removal of intervertebral discs to allow for greater movement One lung ventilation is rarely necessary to improve surgical access, except in high thoracic curves Combined ant & post in single operation results in more rapid recovery & less time in hospital
  50. 50.  Take note aetiology, location & degree of scoliosis All pts require full hx, physical examination & appropriate investigations focusing on CVS & resp. systemRoutine investigations Routine (blood tests ) Additional investigationsPlain CXR FBC ABG – if spirometry notPulm fx tests Coagulation screen possibleFEV1 and FVC Urea & electrolytes ECG & ECHO (non- Ca & phosphate idiopathic scoliosis) Blood cross-match
  51. 51.  Good exercise tolerance & absence of resp. sx indicates acceptable cardio-resp. reserve Pts with more severe degrees of scoliosis > 100°, right ventricular hypertrophy on ECG, or evidence of right HF on examination require ECHO Scoliosis surgery can be well tolerated despite severe restrictive lung dz (FVC <32%) Approx. 25% pts with idiopathic scoliosis have mitral valve prolapse rarely of clinical significance & antibiotic cover is given
  52. 52.  Preop assessment of pt with neuromuscular ds or immobility is more difficult Unable to give a hx of exercise tolerance or perform spirometry adequately Muscular dystrophies m/be complicated by subclinical cardiomyopathy Duchenne muscular dystrophy: >50% have some degree of dilated cardiomyopathy & EF <45% by 15 yo Need ECHO to assess left ventricular fx Normal study does not exclude significant pathology
  53. 53.  Use of invasive monitoring lines & catheters along with postop analgesia plan should be explained fully to pt & family Sedative premed. with oral midazolam (0.5mg/kg) can be offered Pts with Duchenne muscular dystrophy m/be on corticosteroid therapy – require perioperative supplementation
  54. 54.  Aim to maintain stable anaesthetic depth allowing intraop. neurophysiological monitoring Induction by IV propofol Non-depo NMB drug Tracheal intubation with an armoured tracheal tube Anaesthesia maintained by sevoflurane at 0.6 MAC in air & oxygen Infusion of remifentanil Bolus of IV morphine toward the end of surgery Suxamethoniumcontraindicated in muscular dystrophy dt risk of rhabdomyolysis, hyperkalemia, cardiac arrest
  55. 55.  Bld loss & heat loss, potential for haemodynamic instability Addition to standard paediatric GA monitoring :  Invasive arterial pressure monitoring  Urinary catheter 2 large peripheral iv cannulae Central venous cannula if significant comorbidity or inadequate iv access CVP may be misleading as a guide of ventricular filling in prone position Cardiac ouput monitoring with oesophageal Doppler Temp monitoring + IV fluid warmers, warm air blankets at induction and throughout procedure
  56. 56.  Monitor volume status & bld loss carefully in all pts Regular Hb, platelet & coagulation estimations Children with neuromuscular dz are at increased risk of excessive bld loss: they have more osteopenic bone & it has been suggested that the absence of dystrophin causes vascular pathophysiological changes
  57. 57.  Careful positioning to avoid IVC compression Prevent hypothermia Correction of caogulopathy Good surgical technique Compression stockings, pneumatic boots as thromboprophylaxis Avoid anticoagulants Controlled hypotension MAP 50-60 mmHg remifentanil infusion & volatile agent w/out need for vasodilators Hypotension & surgical manipulation may reduce SC perfusion & so risk neurological injury Important to maintain continuous neurological monitoring & adequate haematocrit to ensure oxygen delivery
  58. 58.  Predonation of blood Intraoperative acute normovolaemic haemodilution Intraoperative cell salvage
  59. 59.  SSEP ± MEP Intraoperative wake up test
  60. 60.  Good post-op analgesia essential to allow frequent physiotherapy & early mobilization Reduce risk of resp. complications Multimodal approach Combined simple analgesics, systemic opioids & regional anaesthesia Epidural catheter or paravertebral catheter during an anterior correction can be placed intraop. by the surgeon After initial neurological assessment, a loading dose of LA is given followed by a continuous infusion
  61. 61.  Additional analgesia is needed d/t the size of the wound & the surgical disruption of the epidural space Opioids can be administered intravenously, intrathecally or via the epidural space Epidural infusion + CMI + regular Paracetamol ± NSAIDS
  62. 62.  Good post-op analgesia essential to allow frequent physiotherapy & early mobilization Reduce risk of resp. complications Multimodal approach Combined simple analgesics, systemic opioids & regional anaesthesia Epidural catheter or paravertebral catheter during an anterior correction can be placed intraop. by the surgeon After initial neurological assessment, a loading dose of LA is given followed by a continuous infusion
  63. 63.  Airway assessment & management Anticipate difficult a/way Limited mouth opening & limited neck movement Establish the range of symptom-free neck movement Elicit sn & sx of possible nerve impingement or SC compression Pain on mastication – TMJ involvement Increasing hoarse voice – suggest arytenoid cartilages involvement Atlantoaxial instability Radiograph of cervical flexion & extension for all pts with neurologic sx & those taking regular steroids or dz-modifying antirheumatic drugs
  64. 64.  Neutral position – to prevent damage to neurologic structures This m/be different for each pt & care should be taken to enlist the pt‟s cooperation in finding the most comfortable neck position Extubation – gross assessment of neurologic fx had been completed before extubating as worsening of fx may precipitate need for urgent imaging or re- operation During preop need to warn pt that they may awake with a breathing tube in place & ask to perform simple tasks on command Check for leak before extubation Head-up position & use of corticosteroids may accelerate resolution of edema
  65. 65.  Autosomal dominant d/o Melanogenic abnormalities café-au-lait macules, freckling, hyperpigmentation Tumor formation usually manifests in puberty May present for surgical procedures involving peripheral nervous syst. tumors (neurofibromas), CNS tumors(benign optic gliomas, astrocytomas), scoliosis or other skeletal abnormalities Association with phaeochromocytoma Thorough & systematic approach to pt is essential
  66. 66.  Particular concern airway Difficulties presented by cervical spine immobilization Neurofibromas may develop in the trachea & resp. tree Tracheobronchial tumors m/be asymptomatic for many years & may present with normal chest radiographs Recent history of dyspnea, cough, dysphagia, dysarthria, stridor or change in voice Awake fibreoptic intubation May use dexmedetomidine as sedation preservation of resp. drive (+ fentanyl)
  67. 67.  Infection Preopassessment lung function & CXR Complete treatment Document neurologic deficit pre-op
  68. 68.  Aims to reduce ts trauma, prevent iatrogenic prob. & preserve spinal segmental motion & stability The most compelling advantages of endoscopic procedures over open surgery are:  Smaller incisions & less ts trauma  Minimal bld loss  Earlier return to activities & work  Easier operative approach in obese pts  Local/regional anesthesia combined with conscious sedation can be used  In most cases, less postop. pain medication is required  As a consequence, outpt procedures are possible
  69. 69. ENDOSCOPIC SPINE SURGERYIndications: Contraindications:  Clinically relevant instabilities Lumbar, thoracic & cervical  Central spinal canal stenosis disc herniations with radicular symptoms Relative contraindications: Lateral spinal canal (recess) & foraminal stenoses with  Large disc herniations with radicular symptoms cauda equina synd. or a fresh motor deficit Degenerative facet joint cysts with radicular symptoms  With the exception of cases with large interlaminar windows & good  Interlaminar endoscopic access, adequate decompression may not be possible
  70. 70.  Many surgeons prefer GA for the traditional techniques, but LA with or w/out conscious sedation is an option for most endoscopic approaches However, one consideration should be that in a pt in the prone position, a conversion from local to GA would require complete abandoning of the procedure, endotracheal intubation, repositioning and renewed preparation of the operative field Especially with cervical procedures, unconscious head& neck movement are difficult to control & may incur additional risks
  71. 71.  Interlaminarapproach Posterolateral approach Far or Extreme lateral approach
  72. 72.  Anteriorapproach Posterior approach
  73. 73.  GA Adult & children >45kg double lumen tube Children <45kg may require selective intubation of the ventilated lung Position checked by fibreoptic Pt position in lateral decubitus then check tube position by auscultation & fibreoptic
  74. 74. Univent Cohen Arndt
  75. 75.  Manoeuvres are directed at minimising atelectasis in the ventilated lung & shunt in the non-ventilated lung Set initial VT at 10 ml/kg & adjust resp. rate to maintain normocapnia Use FIO2 0.5 initially & increase to 1.0 if required Ensure proper tube position (auscultate, bronchoscopy) & suction at regular intervals Apply continuous positive a/way pressure to the non- ventilated lung to expand it just enough so as not to interfere with the surgery, thus reduce shunt
  76. 76.  Application of PEEP to the ventilated lung may reduce atelectasis but oxygenation may deteriorate d/t increase in shunt through the other lung Oxygenation can be insufflated into the non- ventilated lung via a suction catheter Alternatively, the non-ventilated lung can be inflated briefly with 100% O2 at intervals Persistent hypoxia that does not respond to the above manoeuvres must be treated with resumption of two-lung ventilation with 100% O2 Failing this, clamping of the pulmonary artery (of the surgical lung) should improve oxygenation
  77. 77.  Spinal anaesthesia in adults, D. A. Raw et. al, BJA 2003; 91: 886-904 Anesthesia for spine surgery, A. Samantaray, Indian Anaesthetists„ Forum 2006 Scoliosis surgery in children, M.A. Entwistle and D. Patel, Continuing Education in Anaesthesia, Critical Care & Pain, BJA , 2006; 6: 1: 13-16 Anaesthesia for scoliosis surgery in children, Euroanaesthesia, Glascow, Woloszczuk – Gebicka 2003
  78. 78.  Clinical Anaesthesiology by G. Edward Morgan Oxford handbook of anaesthesia by Keith G. Allman Yao & Artusios‟s Anaesthesiology Intraabdominal pressure, blood loss and spinal surgery, Anesthesia-Analgesia 2000;91:552–7 Ames et al, Local anaesthesia for laminectomy surgery, British Journal of Neurosurgery, 1999, Vol. 13, No. 6 , Pages 598-600 Case Studies in Neuroanesthesia and Neurocritical Care by George A. Mashour and Ehab Farag

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