Anesthetic management of maxillofacial surgery By: Alaa Samir El Kateb Lecturer of anesthesia and intensive care Ain Shams university

Objectives: - Preoperative airway assessment. - Learn how to perform awake intubation. - How to draw a fluid chart. - What is massive blood transfusion and its complications. - Know complications and prevention of hypothermia.

Le fort classification Transverse crossing floor of nose, separating of the palate from the maxilla. Fracture of maxilla, where body of the maxilla is separated from the facial skeleton (pyramidal in shape) The entire maxilla and one or more facial bones are completely separated from the craniofacial skelton

Anesthetic consideration Airway management (intubation & extubation) Blood loss Hypothermia Eye protection

Airway management !

Airway Anatomy

Airway assessment 1- HISTORY: *Rheumatoid - *Morbid obese *Submandibular abscess *Retropharyngeal abscess *Neoplasm, Radiation, *Scleroderma *Previous tracheostomy *Prolonged intubation *Bleeding lesions *Syndroms e.g. Down *Mandibular, maxillary &/or cervical spine fractures *History of difficult intubation

Cont. Preoperative airway evaluation 2- PHYSICAL EXAMINATION: Thick, short & muscular neck Receding or hypoplastic mandible Edentulous, prominent incisors High arched palate, large tongue Presence of ear or hand deformities

Cont. Preoperative airway evaluation Hyomental distance: 2 fingers Thyromental distance: 6.5 cm Mouth opening: (TMJ) 3-4 cm Neck Movement: 35 degree flexion at lower cervical and 80 degree extension at atlanto-occipital

Cont. Preoperative airway evaluation Mallampati’s : sitting, vocalizing, tongue protruded

- Cormack and Lehane scale The vocal cords visible The vocal cords partially visible (posterior commissure) Only epiglottis Epiglottis Not seen

El-Ganzouri risk index Mouth opening cm≥4<4 Thyromental distance cm> <6 Mallampati classIIIIII-IV Neck movement>90°80°-90°<80° Ability to prognathYesno Body weight Kg< >110 History of difficult intubation none??yes

Awake intubation preparation

Innervation of nasal, oropharyngeal & laryngeal cavities Nasal/Nasopharyngeal Cavity – Trigeminal Nerve (CN V) Oropharynx- Glossopharyngeal Nerve (CN IX) Larynx & Trachea – Branches of the Vagus Nerve (CN X)

I. Anesthesia of the Nasal Mucosa and Nasopharynx ( Sphenopalatine ganglion and ethmoid nerve) - Lidocaine + epinephrine or lidocaine + phenylephrine - Long cotton-tipped applicators: 1 st : 45 degree to the hard palate 2 nd : parallel to the dorsal surface of the nose - Left in place for 5 minutes - Should be done bilaterally

II. Anesthesia of the mouth, oropharynx and base of tongue (Glossopharyngeal & superior laryngeal nerves ) - Lidocaine gel on tongue blade and patient "sucks“. Peak on set 15 min. OR Lidocaine can be placed in a nebulizer for 5-7 min OR The tongue and posterior pharynx are sprayed with the atomizer.

Glossopharyngeal nerve block

Superior laryngeal nerve block

III. Anesthesia of the hypopharynx, larynx and trachea Transtracheal block (RLN)

After anesthetizing the airway you may use: Direct laryngoscopy Blind intubation Retrograde intubation Fiberoptic intubation PLEASE Maintain spontaneous breathing

ctrachcombitube ILMA COPA

LMA_supreme2 AIRtraq glidescope video assessted

TruView

Nasal intubation - Vasoconstrictor minutes earlier. - Insert ETT parallel to hard palate. - Bevel is medial (turbinates are lateral) - During blind nasal: _ Introduce the ETT during inspiration _ You may use capnography

Fiberoptic bronchoscopy - May turn to be an emergency situation. - If to be used, use it as the first choice. - Pull the tongue forward, jaw thrust. - Put the patient in sitting position. - Keep the midline against hard palate. - You may dim room light and use it as illuminating stylet.

Retrograde intubation

- For nasal intubation!!

Submental intubation

Safe extubation “air leak test” is done to evaluate whether or not the patient is capable of breathing spontaneously You may use a hollow introducer or a tube- exchanger, bronchoscope or NGT

Blood loss

- Wide pore canula / central venous access Fluid therapy Deficit Hourly maintenance * fasting hours Maintenance - 4 cc/Kg for 1 st 10 weight - 2 cc/Kg for 2 nd 10 weight - 1 cc/Kg for remaining weight Losses - Ryle - UOP - Bleeding - 3 rd space loss

Gross ’ s simplified formula Allowable blood loss = [(Starting Hct – target Hct) / Starting Hct] X Estimated blood volume. Estimated blood volume Adults: cc/kg Infants: 80 cc/kg Neonates: 85 cc/kg Newborn: cc/Kg Amount to be transfuse (ml)= [Target haemaglobin – Current haemaglobin] X 4 X weight (kg)

Massive blood transfusion American Association of Blood Banks definition: 10 units of blood in 24 hrs or 5 units of blood in 4 hrs

Complications of massive blood transfusion 1- Coagulopathy: At least 1.5 times blood volume to become a clinical problem. 2- Hypothermia. 3- Citrate toxicity: > unit/5 min 4- Hyperkalemia

Hypothermia

Complications of hypothermia: 1- Arrhythmia: PVC (<30°C) – VF (<28°C) 2- ↓ O 2 delivery to tissues: O 2 dissociation curve, VC, ↑ blood viscosity. 3- ↓ GFR and UOP stops at 20°C 4- ↑ blood viscosity, ↑ rouleaux formation, coagulopathy (depressed clotting mechanism and platelets function). 5- Metabolic acidosis. 6- Post-operative shivering.

How to prevent? - ↑ ambient air temperature. - Humidify inspired air - Warm mattress - Plastic or cotton wraps - Warm fluids

Eye protection