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10 February 2012 No. 5 Anaesthesia for Paediatric Adenotonsillectomy NH Gokul Commentator: T Ramsamy Moderator: S Ramcharan Department of Anaesthetics CONTENTS INTRODUCTION ................................................................................................... 3 WHAT IS A TONSILLECTOMY? .......................................................................... 3 ANAESTHETIC CONSIDERATIONS FOR PAEDIATRIC TONSILLECTOMIES .. 6 Obstructive Sleep Apnoea Syndrome (OSAS) ............................................... 6 Airway Management – LMA vs ETT ............................................................... 11 Analgesia ........................................................................................................ 12 Post-Operative Nausea and Vomiting ........................................................... 14 Post Operative Haemorrhage ........................................................................ 15 DAY CASE SURGERY ....................................................................................... 16 CONCLUSION .................................................................................................... 19 REFERENCES.................................................................................................... 20 Page 2 of 21 INTRODUCTION Tonsillectomies are among the commonest surgical procedures children undergo around the world. The procedure was first described in 1000BC in India (2), obviously before the description of anaesthesia. In the 1950’s up to 200 000 tonsillectomies occurred per year in the UK and nearly 1.4 million occurred in the USA in the same time period. During this period there were many indications for the operations and many were performed as prophylactic treatment. Over the last 60 years there has been a marked decline in the number of procedures performed. This is mostly due to the refinement in the indications for tonsillectomies. WHAT IS A TONSILLECTOMY? Anatomy The tonsils are formed by a ring of lymphoid tissue that surrounds the pharynx. They are part of the mucosa-associated lymphoid tissues (MALT) found throughout the GIT. Collectively they form what is known as Waldeyer’s ring. This is made up of 4 groups of lymphoid tissue, namely: Pharyngeal tonsil – a.k.a. Adenoids – found in the nasopharynx Tubal tonsil – posterior to the Eustachian tube Palatine tonsil – found on either side of the back of the mouth; commonly referred to as the “tonsils” especially when inflamed Lingual tonsil – on the posterior region of the tongue Page 3 of 21 WebMD Jan 2012 Page 4 of 21 The surfaces of the tonsils are covered with crypts which allow for antigens from the air and food to enter. Tonsils contain T and B lymphocytes and play a significant role in the immune system. The main blood supply to the tonsils is via tonsillar branch of the facial artery which enters the tonsil near its lower pole. It is also supplied by the lingual artery through its dorsal lingual branches, ascending palatine branch of facial artery, and ascending pharyngeal vessels. Nerve supply to the tonsil is from the lesser palatine nerve and the lingual never which branch from the facial nerve and from the glossopharyngeal nerve via the pharyngeal plexus. Indications for Tonsillectomy The indications for surgery can be broadly separated into infective and enlargement indications. Most ENT societies have guidelines on when tonsillectomy is indicated(3). Most include the following: Recurrent attacks of tonsillitis (typically Streptococcal). - sore throats due to tonsillitis - five or more episodes of sore throat per year - symptoms for at least a year - episodes of sore throat are disabling and prevent normal functioning - very frequent infection (>8 per annum) - those who are hospitalised with extremely severe tonsillitis or peritonsillar abscess (quinsy) Enlarged tonsils causing obstruction of the airway, which may be the cause of Obstructive Sleep Apnoea – recurrent airway obstruction at night – and this has serious effects on health and wellbeing. Possible malignant disease in the tonsils – typically squamous carcinoma or lymphoma. (Indications for Tonsillectomy: Position Paper ENT UK 2009) The American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS) include enlargement causing feeding problems and halitosis as indications. Page 5 of 21 Contraindications Contraindications for tonsillectomy include the following: Bleeding diathesis Poor anesthetic risk or uncontrolled medical illness Anemia Acute infection Surgical Technique Positioning – surgeon at head end, no access to patient after draping - Extension of neck to facilitate access – Rose position - Use of mouth gag to keep mouth open - B. G. Fennessy et al(4), small single institute study, showed 96% of ETTs moved during positioning with Boyle-Davis gag(4) - Other complications include damage to teeth, fissures in lips, and dislocating jaws Cutting technique – many different ways to remove tonsils - Sharp dissection with knife, scissors - Using electrocautery, harmonic scalpel, radiofrequency ablation, carbon dioxide laser - Electrocautery - Leinbach RF, et al(3), showed that electrocautery associated with more post op pain, minimal difference in post op bleeding especially in adults. ANAESTHETIC CONSIDERATIONS FOR PAEDIATRIC TONSILLECTOMIES Obstructive Sleep Apnoea Syndrome (OSAS) OSAS is a common indication for paediatric tonsillectomies where it is commonly curative. It is thought to affect between 1 and 3% of children(5). Children with severe OSA have a higher incidence of perioperative complications and may need postoperative High care or ICU admission(5). OSA is a sleep disorder characterised by disordered breathing with intermittent upper airway obstruction which results in abnormal sleep patterns. Upper airway obstruction may result in apnoeic events, or hypopnoea. Work of breathing is also increased due to increased resistance in narrowed or obstructed airways. All of these fall under the syndrome of Sleep Related Breathing Disorders (SRBD). SRBD refers to a spectrum of conditions that includes snoring, upper airway resistance syndrome, obstructive hypopnoea syndrome and OSA. In children the mildest form of OSA in Upper Airway Resistance Syndrome. Page 6 of 21 Presentation OSA presents differently in children and adults. Deborah A. Schwengel, et al; 2009 International Anesthesia Research Society In children younger than five years, snoring is the most common presenting complaint(5). Other sleep symptoms include: - mouth breathing - sweating - paradoxic rib-cage movement - restlessness - frequent awakenings - apnoeic episodes Children five years and older, in addition to snoring (5), commonly exhibit: - enuresis - behaviour problems - deficient attention span - failure to thrive Children with OSA don’t often present with daytime somnolence in contrast to adult patients. Obese children, however, may have somnolence as a presenting symptom. In extreme cases of OSA in children, chronic hypoxia, hypercarbia and acidosis can present with pulmonary hypertension and cor pulmonale(5). Page 7 of 21 Diagnosis(5) Overnight polysomnography is the gold standard test for SRBD. In this test multiple parameters are measured while the patient sleeps. These include - Respiratory effort—assessed by abdominal and chest wall movement - Airflow at nose and or the mouth - Arterial oxygen saturation - End-tidal CO2 or transcutaneous CO2 in children - Electrocardiograph - Electromyography to monitor arousals - Electroencephalography, electrooculography and electromyography for sleep staging Using this data the severity of the condition can be graded and managed accordingly. Obstructive apnoeas and hypopneas identified during a sleep study are combined to provide the Apnoea–Hypopnoea index (AHI). The AHI is defined as the number of obstructive events that occur every hour. Extent of desaturation during these events is also used for grading. Deborah A. Schwengel, et al; 2009 International Anesthesia Research Society(5) Page 8 of 21 Pre Op Assessment and Management Airway – features of dysmorphism – association with cerebral palsy, Trisomy 21 - Assess degree of obstruction by tonsils - Handling of secretions and muscle tone - Malampati score Management – preoperative CPAP/BiPAP therapy may improve pulmonary hypertension and reduce the patient’s surgical risks. The pressures required to treat the patient’s OSA are determined during polysomnography. - The child’s preoperative CPAP/BiPAP regimen can also be used in postoperative care - The patient’s response to adenotonsillectomy and need for long-term CPAP may need to be reviewed weeks after the operation(5). Cardiovascular - childhood OSA is associated with hypertension and arterial blood pressure - Cardiac evaluation is recommended for any child with signs of right ventricular dysfunction, systemic hypertension or multiple episodes of desaturation below 70% - Electrocardiogram and chest xray are not sensitive enough and Echocardiography is recommended - Routine blood gas analysis is not necessary, but a urea and electrolytes can help to identify a patient with compensatory metabolic alkalosis and a raised haemoglobin level may identify the patient with severe chronic hypoxemia(5). Premedication - Sedative and anaesthetic medications alter the CO2 response curve. Patients with OSA rescue themselves during obstructive episodes by arousal from sleep, but sedatives or residual anaesthetics may make it impossible for these patients to wake themselves up from an obstructive episode. - Use of sedation preop can be done, but only under strict observation(5). Intraoperative Management (5) Induction – No consensus on ideal technique - Non-obese children with simple adenotonsillar hypertrophy and without maxillofacial malformations are often easily mask-ventilated once an oral airway is placed, and endotracheal intubation is also usually straightforward(5). - OSA patients are obviously at higher risk of airway obstruction once anaesthesia is induced and upper airway muscles relax - Positioning in an upright or lateral position, use of a jaw thrust manoeuvre, delivery of positive pressure by face mask and placement of an oral airway may aid in relieving the obstruction(5). Page 9 of 21 - Airway obstruction in spontaneously breathing patients can result in negative pressure pulmonary oedema - IV induction can be used to rapidly induce anaesthesia ready for airway instrumentation, especially in OSA patients Emergence – Deep extubation is not recommended in patients with severe OSA and those at risk of post-op OSA - Extubation should be done when patient is awake in controlled environment - Position child in lateral decubitus or prone position - CPAP can be used to assist ventilation and relieve airway collapse - nasal airway before extubation might be considered in more severe cases - Reintubation may be required in some patients Postoperative Care(5) Analgesia – OSA patients used to chronic hypoxemia causes them to be more susceptible to the respiratory depressant effects of opioids - OSA patients may also be more sensitive to the analgesic effects of opioids. Children with oxygen saturation of <85% on polysomnography required half the morphine dose as those with less desaturation to achieve the same level of analgesia(5,6) Post-op respiratory complications – paediatric patients with OSA are at increased risk for postoperative respiratory complications. Rates of complications range from 6.4% to 27% but depend on age, severity of OSA and comorbidities(5) - Children <3 years of age have twice the risk of children who are 3–6 years old - complications included oxygen desaturation <90%, increased work of breathing, oedema, atelectasis, infiltrate, pneumothorax, pneumomediastinum, or pleural effusion - Other complications associated with severe OSA include laryngospasm, apnoea, pulmonary oedema, pulmonary hypertensive crisis, pneumonia and perioperative death - Although adenotonsillectomy improves most patients, children with disorders of pharyngeal tone or craniofacial abnormalities may have residual airway obstruction during the postoperative period - polysomnography can be repeated post to determine the risk of continued OSA symptoms - Very severe OSA, very young children and those with co-morbidities may need post-op ICU care Page 10 of 21 Airway Management – LMA vs ETT(23) With ENT surgery the airway needs to be well secured. Due to surgical positioning access to the patient is limited and surgical work can result in disconnections and dislodging of the device. Below is a table comparing the endotracheal tube to the Laryngeal mask airway. The LMA used is often the flexible, re-enforced type which allows for easier positioning out of the surgical field. R. Ravi; Continuing Education in Anaesthesia, Critical Care & Pain; Volume 7 Number 2 2007 ETT - Most effective at securing airway - Limited airway soiling when throat pack used - Disadvantages of main concern are - extubation – awake vs. deep; airway complications like laryngospasm, bronchspasm, aspiration - association with increased PONV - local trauma and pain caused by tube LMA/FLMA Page 11 of 21 - The biggest limitation in LMA use is experience of both surgeon and anaesthetist - Application of mouth gags also carry similar risk in dislodging the LMA as it does an ETT Analgesia Tonsillectomies are very painful. In children without Obstructive disease opioids and sedative analgesia need to be used with extreme caution. Other options for analgesia are discussed below. Opioids - Opioids are often necessary to treat tonsillectomy pain. - All opioids drugs have been used in tonsillectomies - The common side effects of nausea and vomiting and respiratory depression are limiting factors - Tramadol – found to be a good alternative to morphine. Has similar analgesic profile but much less emetic effect; (T. Engelhardt, et al; Pediatric Anesthesia; March 2003) Paracetamol - Recommended for most patients PR route is less frequently used IV, PO routes work PR route shows increased duration of action compared to IV, Capici F, et al 2008. NSAID - Most NSAIDs have been used to treat tonsillectomy pain. Most common diclofenac, ibuprofen, ketoprofen - The biggest concern with NSAIDs is their anti-platelet effect and associated haemorrhage. - NSAIDs significantly decrease the amount of opioids needed to manage pain. This also reduces nausea and vomiting induced by opioids - Ideal in day patient surgery - Pre-operative NSAIDs are associated with increased bleeding risk intraop and have also been shown to be less effective analgesia - 2003 M. Cardwell, et al, reviewed clinical trials from MEDLINE, EMBASE and Cochrane. His team concluded that NSAIDs did not increase post op bleeding risk and significantly decreased nausea and vomiting - Ketorolac uses increases bleeding risk by 4 -18%, and should be avoided - The use of aspirin, however, is not recommended for post tonsillectomy analgesia(8) Page 12 of 21 - Overall most authors recommend NSAIDs Local Anaesthetic - Infiltration before and after dissection of the tonsils has been attempted with mixed results - The glossopharyngeal nerve, Internal carotid and the lingual artery are all in close proximity to the tonsils - In adult patients tonsillectomies can be performed with only local infiltration(10,11) - Use of bupivicaine for infiltration has been shown to be as effective as PR paracetamol but due to risk of injection, it is not recommended(12) - Use of topical lignocaine at the end of surgery is also effective(13) - Glossopharyngeal nerve blocks can also be attempted but post operative breathing and swallowing abilities might be affected - The risk benefit issues with local infiltration favour avoiding its use and using alternative analgesia Others - Ketamine – useful analgesic. Reduced opioid requirement post op - peritonsillar infiltration with ketamine can be effective as well(18), - Steroid – dexamethasone – single intra-op bolus of 0.1-0.15 mg has been shown to reduce post-op pain and PONV - Surgical technique – excessive use of diathermy increases tissue trauma and pain; “cold” techniques are associated with less pain; partial dissection of the tonsils, leaving the base in-situ can also reduce post op pain - Preoperative counselling and Fasting – A Finnish study in 2009 attempted to use preoperative counselling and patient education to reduce post-op pain and PONV. They found that the counselling about active preoperative nutrition significantly reduces the child's pain during the first post tonsillectomy hours and might prepare the child to better tolerate the stress of potential postoperative nausea and vomiting. - Maintaining good fluid intake post-op also decreases pain and discomfort - Time-dependent dosing of analgesia was more effective than PRN dosing. In this way the child will always have analgesia on board Page 13 of 21 Post-Operative Nausea and Vomiting Tonsillectomy is associated with PONV(5). Factors that increase nausea and vomiting in the tonsillectomy patient include: - Surgical - Trigeminal nerve stimulation – the posterior oropharynx and faucial mucosa supply stimulus directly to the vomiting centre in the medulla - Swallowed blood – B-D gag can open the hypopharynx and allow blood to enter the oesophagus, use of muscle relaxants increases this - Anaesthetic - uses of opiates - volatile anaesthetics - endotracheal tubes - Patients - incidence of postoperative vomiting is low at birth and increases to a peak in late childhood (between 6–16 years) before decreasing in adulthood(17). Management - Managing the causes - excessive electrocautery - Avoiding too much opioids - Suctioning blood in pharynx and stomach - TIVA in susceptible patients - Drugs - Dexamethasone – anti-inflammatory effect reduces pain and vomiting stimulus; 2011 meta analysis of RCTs using dexamethasone in tonsillectomies, showed it effectively reduced PONV, pain(16) - Meta Analysis done in 2006(17) using Cochrane Controlled Trials Register, MEDLINE and EMBASE, showed Dexamethasone and anti-serotinergic agents to be the most effective in reducing PONV - It also found metoclopramide to have some effect. There is not sufficient evidence to suggest that perphenazine or droperidol, in the doses studied, are efficacious, nor were gastric aspiration or acupuncture - Combination therapy works best using dexamethasone and an anti-serotinergic together Page 14 of 21 Post Operative Haemorrhage - Primary haemorrhage is defined as bleeding that occurs within the first 24 hours after the procedure and is generally attributed to surgical technique and the reopening of a blood vessel. Rates of primary haemorrhage range from 0.2% to 2.2% of patients(19). - Secondary haemorrhage occurs more than 24 hours following the procedure, often between 5 and 10 days, and is usually caused by sloughing of the primary eschar as the tonsil bed heals by secondary intention. Rates of secondary haemorrhage range from 0.1% to 3%(19). - Other risk factors for bleeding include(19): - increasing patient age - male gender - history of recurrent acute tonsillitis (3.7%) - previous peritonsillar abscess - rate is highest in quinsy patients (5.4%) - pharyngeal obstruction and OSA (1.4%) - Coagulopathies – post operative bleeding due to coagulopathies can occur, but are very rare. Full screening of all patients can be expensive and delaying. “Coagulation tests results are irrelevant for the course of tonsillectomy and postoperative bleeding event. Personal medical history is important in predicting post tonsillectomy haemorrhage(20) Management(19) - If need for surgical intervention, anaesthetist involved again - Review of record of original surgery - Difficult airway, medical disease, intraop blood loss and fluid replacement - Ask about duration of bleeding attack & amount of blood vomited - Quick history & examination – child’s volume status, hypotension - Before induction – fluid resuscitation crystalloids/colloids - Hct , Hb & coagulation profile - cross-matching & preparation of packed RBCs - For Induction – child now has full stomach (blood) and blood in mouth, pharynx – difficult intubation - Left lateral position with head down to drain blood out of mouth – can intubate in this position or turn supine and RSI. - Could keep child breathing – aim for bubbles in pharynx full of blood - Continue resuscitation during operation - Maintenance – maintain cardio-stability - Extubate awake in lateral position Page 15 of 21 Surgical management - Pressure applied to a bleeding tonsil fossa by using a sponge and a long clamp, electrocautery of the tonsil bed, use of further topical hemostatics, or ligation of the ipsilateral carotid artery as the last resort. Diathermy is thought to be superior to ligation because of the risk of perforating large vessels with the needle(19). Another last resort is ligation of other large vessels, such as the external carotid artery(19). DAY CASE SURGERY With most paediatric tonsillectomies patients are eligible for admission as a day case, i.e. arriving at the hospital in the morning and not spending the night in the hospital. Patients need to be fit and healthy, either ASA 1 or 2. For paediatric tonsillectomies, certain exclusion criteria should be assessed UK multidisciplinary working party on SRBD and tonsillectomy 2008 Page 16 of 21 Social factors as well need to be considered – access to transport, distance to hospital, number of able care-givers at home. Most centres have a protocol treatment plan for day case surgery. P J Robb; The Journal of Laryngology & Otology October 2011 The principles include: safety, short acting drugs, surgical technique, prevention of common post-op complications (pain, PONV, haemorrhage). Readmission Sometimes post op admission or re-admission occurs. This is due to the occurrence of complications. Page 17 of 21 The chart below shows the most common complications. P J Robb; The Journal of Laryngology & Otology October 2011 Page 18 of 21 CONCLUSION Adenotonsillectomy is a common operation performed worldwide. At a glance it seems like a simple straight forward operation, but it is associated with many complications. Common complications can be anticipated and pre-emptively treated. Airway issues from obstruction, difficult intubation, as well as airway device and access should be planned preoperatively. Analgesia and PONV should both be prevented rather than treated when they occur. Most centres can perform adenotonsillectomies as day procedures. In South Africa, especially in the public sector, social factors play a bigger role in deciding on day case operations. Page 19 of 21 REFERENCES 1. http://www.drtbalu.co.in/tonsil.html; January 2012 2 Amelia F Drake, MD “Tonsillectomy “; Chief Editor: Arlen D Meyers, MD, MBA; Medscape; January 2012 3. Indications for Tonsillectomy: Position Paper ENT UK 2009 4. B. G. Fennessy “Safety implications of the Boyle–Davis mouth gag and tracheal tube position in tonsillectomy”; Br. J. Anaesth. (2010) 105 (6): 863-866 5. A. Schwengel”Perioperative Management of Children with Obstructive Sleep Apnea”; Deborah; (Anesth Analg 2009; 109:60–75) 6 Brown KA, Laferriere A, Lakheeram I, Moss IR “Recurrent hypoxemia in children is associated with increased analgesic sensitivity to opiates. “;; Anesthesiology 2006;105:665–9 7. Thomas Engelhardt MD, FRCA, Elizabeth Steel FRCA, Graham Johnston FRCA “Tramadol for pain relief in children undergoing tonsillectomy: a comparison with morphine”; Peadriatric Anaesthesia; Volume 13; Issue 3; March 2003 8. S. Kumar, et al”Non-steroidal anti-inflammatory drugs and postoperative bleeding following adenotonsillectomy in paediatric patients”; Arch Otolaryngol Head Neck surg; Jan 2008 9. Cardwell M, Siviter G, Smith A “Nonsteroidal Antiinflammatory Drugs and Perioperative Bleeding in PediatricTonsillectomy”; Anesth Analg 2005;101:1558 10. M. Usman, et al “Tonsillectomy under local anaesthetic. A safe cost effective alternative in Pakistan”;; Pakisatn journal of Otolaryngology; 2005; 21; 56-58 11. Bredenkamp JK, Abemayor E, Wackym PA, Ward PH “Tonsillectomy under local anesthesia: a safe and effective alternative.” ; Am J Otolaryngol. 1990 JanFeb;11(1):18-22. 12. Dahi-Taleghani M, Mousavifard S, Tahmoureszade S, Dabbagh A. “Rectal acetaminophen versus peritonsillar infiltration of bupivacaine for postoperative analgesia after adenotonsillectomy in children.” ; Eur Arch Otorhinolaryngol. 2011 Apr;268(4):581-4. 13. Rhendra Hardy MZ, Zayuah MS, Baharudin A, Wan Aasim WA, Shamsul KH, Hashimah I, Suan YA. “The effects of topical viscous lignocaine 2% versus perrectal diclofenac in early post-tonsillectomy pain in children.” ; Int J Pediatr Otorhinolaryngol. 2010 Apr;74(4):374-7 Page 20 of 21 14. Emmanuel Marret, M.D., Antoine Flahault, M.D., Ph.D.,Charles-Marc Samama, M.D., Ph.D., Francis Bonnet “effects of Postoperative, Nonsteroidal, Antiinflammatory Drugs on Bleeding Risk after Tonsillectomy” Meta-analysis of Randomized, Controlled Trials ; Anesthesiology 2003; 98:1497–502 15. AMD Bennett and PJ Emery “A Significant Reduction in Paediatric PostTonsillectomy Vomiting through Audit”;; Ann R Coll Surg Engl. 2008 April; 90(3): 226–230. 16. Mokhtar Elhakim MD, Naglaa M. Ali MD, Inas Rashed MD, Mostafa K. Riad MD, Mona Refat MD”Dexamethasone reduces postoperative vomiting and pain after pediatric tonsillectomy”; OBSTETRICAL AND PEDIATRIC ANESTHESIA CAN J ANESTH 2003 / 50: 4 / pp392–397 17. C. M. Bolton, P. S. Myles, T. Nolan and J. A. Sterne “Prophylaxis of postoperative vomiting in children undergoing tonsillectomy: a systematic review and metaanalysis”;; British Journal of Anaesthesia 97 (5): 593–604 (2006) 18. El Sonbaty MI, Abo el Dahab H, Mostafa A, Abo Shanab O “Preemptive peritonsillar ketamine infiltration: postoperative analgesic efficacy versus meperidine.”;; Middle East J Anesthesiol. 2011 Feb;21(1):43-51 19. Ravie Abdelwahab “Anesthesia For Adeno-tonsillectomy” Presented by 20. Zagólski O “Post-tonsillectomy haemorrhage--do coagulation tests and coagulopathy history have predictive value?”; Acta Otorrinolaringol Esp. 2010 JulAug;61(4):287-92. 21. S. Dennis, M. Georgallou, L. Elcock, D M. Brockbank “Day case tonsillectomy – theSalisbury experience”; The Journal of One-Day Surgery 22. Leinbach RF, et al “Hot versus cold tonsillectomy: a systematic review of the literature”; Otolaryngol Head Neck Surg. 2003 Oct;129(4):360-4. 23. R. Ravi; “Anaesthesia for paediatric ear, nose, and throat surgery” Continuing Education in Anaesthesia, Critical Care & Pain; Volume 7 Number 2 2007 Page 21 of 21