FOR OTOLARYNGOLOGY (ENT) AND OPHTHALMOLOGY



CSF Leak Repair


Often performed via endoscopic sinus approach for spontaneous leak with rhinorrhea


•  Usually requires intrathecal injection of fluorescein (aids in localization under FESS)


•  May place lumbar drain for 48- to 72-hr postop CSF drainage


•  CSF opening pressure may be of prognostic utility


•  Surgeon may request periop meningococcal meningitis prophylaxis (e.g., ceftriaxone)


Microdirect/Suspension Laryngoscopy


•  Performed by otolaryngologist for a range of indications


•  Employs specialized laryngoscopes for exposure of anatomy/pathology


•  May use robot-assisted techniques & laser devices


•  Procedure is highly stimulating for relatively brief periods


•  Pts often have difficult airways & significant comorbidities


Indications


•  Tumors of larynx, oral cavity, pharynx, hypopharynx


• Biopsy, laser ablation, robot-assisted micro-resection


•  Vocal cord surgery


• Resection of vocal cord polyp


• Vocal cord injection for cord paralysis


• Insertion of mechanical larynx (artificial voice box)


•  Tracheal stenosis—dilation/ablation of lesions


•  Laser ablation/direct chemotherapy of papilloma


Special Considerations


•  Preop discussion with surgeon regarding airway management


•  Potentially difficult airway


• Prior surgery with scarring or postradiation changes (immobile larynx)


• Supraglottic/laryngeal masses or tracheal abnormalities


• Friable tissue → bleeding


•  Positive-pressure mask ventilation may be challenging/impossible


•  Airway = operative field & bed = rotated away


•  Anesthetic gases may leak to environment/surgeon (open system)


•  Intermittent apnea may be required for surgical access


•  ETT may distort surgical anatomy & impede surgical access


•  Laser ablation may be used (requires ↓ FiO2)


• Use jet ventilation, apneic technique or laser tube


• Fill laser tube balloons with methylene blue saline


• Use airway fire protocol


•  Surgeon may desire spontaneous ventilation (assess vocal cord movement)


•  Intense but fleeting/intermittent stimulus


• Requires constant communication between surgeon & anesthesiologist


Anesthetic Management


•  GA usually indicated (owing to intense procedure stimulus)


•  Sedation & spontaneous ventilation in selected cases (with cooperative pts)


• Requires anxiolysis & extensive topicalization with local anesthetic


•  Anesthesiologist often induces GA & shares airway management with surgeon


• Surgeon should be present prior to induction of anesthesia


•  Airway management includes a variety of options


• ETT (e.g., 5.0–6.0 mm ID) placed under laryngoscopy


• Catheter for subglottic jet ventilation placed under direct visualization (see text box, page 21–5) or jet via specialized laryngoscope


• Intermittent apnea with mask ventilation


• Airway device (if used) may be periodically removed for surgical access


•  TIVA technique preferable to inhaled agent


• ↓ OR contamination with inhalation gas


• More consistent depth of anesthesia


• Propofol & titratable, short-acting narcotic often used


•  Muscle relaxation must be individualized for each case


• Consider airway management, operating conditions, need for spontaneous ventilation


• Inhalational induction may be considered


Medialization Thyroplasty (Vocal Cord Medialization)


•  Procedure performed to treat vocal cord paralysis/bowing


•  Partial resection of thyroid cartilage & prosthesis placement


Special Considerations


•  Pt cooperation = important component


•  Anesthesia best provided with sedation & local injection


• Pt able to phonate on command during surgery


• Vocal cord movement observed under nasopharyngeal laryngoscopy


• Surgical incision similar to partial thyroidectomy


• Dexmedetomidine infusion is an excellent option for cooperative sedation


PROCEDURES ON THE INNER EAR AND MASTOID



Stapedectomy


•  Usually light sedation with local anesthesia (GA for selected pts)


•  Sedation allows for intraop testing of hearing acuity


•  Titrate meds (fentanyl, midazolam, propofol, dexmedetomidine) to allow pt cooperation


•  Excessive sedation may lead to disinhibition & movement (precludes safe operating under the microscope)


•  Some centers are investigating use of pt-controlled sedation


Myringotomy Tube Placement (Placement of Ear Tubes)


•  Very short procedure, usually performed in pediatric pts under mask GA


•  IV access not necessary; can use IM analgesics (ketorolac & fentanyl)


TONSILLECTOMY/PAROTIDECTOMY/UVULOPALATOPHARYNGOPLASTY


Tonsillectomy and Adenoidectomy


Indications


•  Recurrent infection


•  Obstructive sleep apnea due to hypertrophic tonsillar/adenoid tissue


Special Considerations


•  Potential for difficult mask/airway—particularly in adults


•  Consider oral RAE tube, secure in midline


•  Procedure usually indicated owing to recurrent infection


• May be semiurgent even in the setting of active infection


•  Short procedure necessitates careful use/titration of muscle relaxants


•  Surgeon removal of mouth gag may result in extubation—monitor closely


•  “Bring back” tonsil for bleeding common


• Aggressive preinduction volume resuscitation (esp pediatric patients)


• RSI or plan for potentially difficult airway (blood in airway & edema)


• Pediatric patients with sleep study evidence of recurrent hypoxemic episodes may demonstrate increased sensitivity to opiate therapy


• Exogenous opiate requirements to provide effective postop analgesia may be reduced by up to ½ normal per kilogram dosing


• Consider scheduled titration of opioids and extended cardiopulmonary monitoring (including possible overnight admission to monitored, inpatient unit) to increase effective surveillance of postop respiratory events


Parotidectomy


•  GA with ETT; consider nasal RAE if deep lobe is to be resected


• Nasal tube precautions (oxymetazoline to nares, gentle dilation, tube sizing)


• Always a risk of significant bleeding with nasal tube placement (afrin & lubricant)


•  Facial nerve monitoring; avoid additional muscle relaxation after induction


Uvulopalatopharyngoplasty (UVA)


•  Performed for treatment of obstructive sleep apnea


•  Airway management: Mask ventilation/intubation may be difficult


•  Review sleep study results—apnea/hypopnea index for severity


•  Consider RAMP positioning for obese patients


•  Pts may require noninvasive ventilation in PACU/floor postop


TRACHEOSTOMY


Indications


•  Ventilator-dependent resp failure


•  Chronic aspiration


•  Airway tumor/injury with airway compromise


•  Acute stridor/bilateral vocal cord paralysis


Special Considerations


•  If already intubated: Vent settings, O2 & PEEP required, intubation method & difficulty


•  If not intubated: Consider awake vs. asleep tracheostomy


•  If in resp failure/ARDS: May require special ventilator settings


• Conventional OR ventilator limited (consider ICU vent)


• Pt may not tolerate vent, disconnect (loss of PEEP)


•  May not tolerate lowered FiO2 during electrocautery


•  Considerable bleeding is rare but possible (aberrant vasculature)


Anesthetic Management


•  Awake tracheostomy (see box, page 21–5)


•  GA: Inhalational or TIVA; muscle relaxation may optimize surgical conditions


•  Potential for ETT balloon puncture upon tracheal incision


• Deflate ETT balloon prior to tracheal incision


• Consider advancing ETT (balloon) prior to tracheal incision


• Withdrawal to just above tracheotomy site under direct surgical visualization


•  Do not fully extubate until tracheostomy is in place & secured


• If tracheostomy lost, ETT can be quickly readvanced distal to tracheotomy


•  Lower FiO2 (<30%) if monopolar cautery to be used after tracheotomy


Management of Existing Tracheostomy


•  Does tracheostomy have a balloon/cuff?


•  Will positive-pressure vent be required? (Limited with uncuffed tracheostomy)


•  Will unusual positioning be required?


•  Is tracheostomy <7 d old?


Management of Mature Tracheostomy (>7 d)


•  Suction existing cannula


•  Denitrogenate with 100% O2 via tracheostomy


•  Controlled inhaled induction with potent agent (e.g., sevoflurane) or IV induction


•  Exchange tracheal tube with a lubricated, wire-reinforced ETT that has the same inner diameter or one size smaller than tracheostomy tube


•  Advance tube such that black markings are positioned at stoma & check for bilateral breath sounds


•  Replace tube with clean tracheostomy tube at case completion after resumption of spontaneous ventilation if uncuffed trach


Management of Fresh Tracheostomy


•  Fresh tracheostomy (<7–10 d) requires interdisciplinary management


•  Should generally not be removed outside OR (no tract)


•  Fresh tracheostomy dislodgement = surgical emergency


• Call for surgical support & fiberoptic bronchoscope


• Put sterile gloves on & plug tracheostomy site with finger


• Do not attempt blind replacement of tracheostomy


• Risk of subcutaneous placement, bleeding, & trauma


• Attempt mask ventilation


• Place LMA if failed/difficult mask ventilation


• Attempt intubation across tracheostomy site by laryngoscopy


• Consider fiberoptic intubation if unsuccessful


• Advance ETT balloon past tracheotomy


• If intubation fails & ventilation is adequate, proceed to OR


• Tracheostomy replacement via trans-LMA fiberoptic or videolaryngoscopic guidance may be considered in stable clinical circumstances with experienced personnel


• If above efforts fail, surgical reexploration at bedside






PROCEDURES IN OPHTHALMOLOGY


Special Considerations


•  Extremes of age (pediatrics—strabismus repair) (geriatrics—cataract surgery)


•  Many ophthalmologists perform regional blocks themselves


•  Complications from movement may result in blindness


•  Appropriate precautions (see above) for laser surgery


•  Access to airway is limited during surgery


Special Medications in Ophthalmologic Population


•  Echothiophate for glaucoma


• Acetylcholinesterase inhibitor → prolongs action of succinylcholine


• Systemic effects include bronchospasm, bradycardia, hypertension


•  Sulfur hexafluoride gas for retinal detachment


• Pt may have intravitreal gas bubble up to 21 d postop


• Avoid N2O due to potential for catastrophic air expansion


•  Consider avoidance of succinylcholine in selected circumstances


• Globe injury → increased intraocular pressure with fasciculation (succinylcholine is not absolutely contraindicated)


• Prolonged contracture of ocular musculature after dosing may interfere with forced duction test (FDT) in strabismus surgery


•  Pilocarpine & carbachol


• Drugs that promote efflux of aqueous humor by producing miosis


• Parasympathomimetics (cholinergic agonist)


• Systemic effects = parasympathetic effects (bradycardia)


•  Epinephrine


• Systemic effects may lead to tachycardia/angina


•  Acetazolamide


• Carbonic anhydrase inhibitor


• Systemic effects include metabolic acidosis, hypokalemia, ↓ ICP


•  Timolol


• β-blocker


• Systemic effects include bradycardia, hypotension, bronchospasm


•  Oral glycerol side effects: Nausea, vomiting, hyperglycemia


•  Mannitol side effects: Volume overload, renal failure


Cataract Surgery: Clear Corneal Phacoemulsification


•  Pts often elderly with multiple comorbidities


•  Procedures usually <1 hr


•  Anesthetic goals


• Akinesia of the eye & eyelid; adequate analgesia & pt cooperation avoidance of oculocardiac reflex


•  Sedation with regional block or topicalization = preferred method


• Local infiltration with sedation


• Regional block with local infiltration & sedation (see table below)


• Provided by surgeon or anesthesiologist


• Brief deepening of anesthesia facilitates block placement


• Options include retrobulbar block; peribulbar block, subtenon’s block


• Block complications: Retrobulbar hemorrhage, globe perforation, optic nerve damage, brainstem anesthesia


• GA for selected pts (complex procedures/unable to cooperate or stay supine)


Strabismus Surgery


•  Indication: Reposition muscles to treat ocular malalignment


•  Surgery almost exclusively performed in pediatric pts


•  ↑ Incidence of postop nausea & vomiting


•  ↑ Risk of intraop oculocardiac reflex (see box below)


•  Usually performed under GA with ETT


•  Nondepolarizing muscle relaxation may aid diagnostic utility of FDT & surgical operating conditions


Other Procedures


•  Repair of ruptured globe


• Frequently emergent procedure with aspiration risk concerns (full stomach, head & associated injuries)


• Commonly requires GA with ETT


• Consider LMA in select circumstances (pts often have full stomach)


• Emphasis on control of intraocular pressure (succinylcholine may ↑ IOP)


• Avoid coughing or bucking during induction & intubation


•  Intraocular surgery: Enucleation, vitrectomy, corneal transplantation, glaucoma decompression, repair retinal detachments


• Control of eye movement & intraocular pressure critical


• GA preferred


• Intraocular epinephrine may be used to aid papillary dilatation


• Monitor for systemic effects


•  Detachment repair injects intraocular air or sulfur hexafluoride gas


• Avoid N2O or discontinue well before injection


• Avoid N2O for subsequent surgery within 3 wks





Peribulbar Block (25–27 gauge, 25 mm needle)


•  Safer (needle inserted outside of extraocular muscle cone), but slower onset


•  Primary gaze position → 2 injections above & below globe


Inject ≈5 mL local into superonasal orbit & ≈5 mL inferotemporally between lateral 1⁄³ & medial ²⁄³ of lower orbital margin


Retrobulbar Block (25–27 gauge, 3 cm needle)


•  Faster onset; must anesthetize conjunctiva before needle introduction


•  Insert needle halfway between lateral canthus & lateral limbus in lower conjunctiva


•  Direct needle straight back until the tip is beyond globe, → then direct needle toward apex of orbit to enter space behind globe between inferior & lateral rectus muscles


•  Insert to depth of 25–35 cm; inject 4 mL local


Subtenon’s Block (25 gauge needle)


•  Injection of local anesthetic directly into posterior aspect of subtenon’s space


•  Insert needle to contact conjunctiva between eyeball & semilunaris fold (depth <1 mm)


Advance needle anteroposteriorly with globe directly slightly medially by needle until “click” is felt, at a depth of 15–20 mm (episcleral location)


•  Return globe to primary position; aspirate → inject local


•  Stop at sign of chemosis (conjunctival edema) & apply ocular compression


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Aug 28, 2016 | Posted by in ANESTHESIA | Comments Off on FOR OTOLARYNGOLOGY (ENT) AND OPHTHALMOLOGY

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