Dr majidinejad We describe basic airway skills including

Dr majidinejad

We describe basic airway skills, including opening the airway, O 2 therapy, BMV, and extraglottic airway (EGA) devices

� Upper airway obstruction most commonly occurs when patients are unconscious or sedated � In these situations, tongue moves posteriorly into the upper airway when the patient is in supine position

� but research in patients with obstructive sleep apnea using CPAP supports the concept that the airway collapses like a fexible tube

� It is widely accepted that the jaw-thrust-only (without head tilt) maneuver should be performed in patients with suspected cervical spine injury, but there is no evidence that it is safer than the headtilt/chin-lift maneuver

� Importantly, the addition of CPAP may relieve airway obstruction when simple manual positioning maneuvers fail.

� most common description of this maneuver is head tilt, jaw thrust, and mouth opening. � Other authors describe the triple maneuver differently—as a combination of upper cervical extension (head tilt), lower cervical felxion, and jaw protrusion (jaw lift)

PATIENT POSITIONING best way to position a patient’s head and neck for opening the upper airway is “sniffng position � In normal-sized supine adults, this is accomplished by elevating the head about 10 cm while tilting the head back �

� Morbidly obese patients require much more head elevation to achieve the proper sniffng position

� In young children, this position is often achieved without lifting the head because the occiput of a child is relatively large

Intervention is required when the patient is not moving air or has altered mental status. � Some patients with upper airway obstruction can be ventilated and oxygenated with aggressive high-pressure BMV, so always try this if standard BMV fails �

� Heimlich maneuver is most effective when a solid food bolus is obstructing the larynx � If a choking patient loses consciousness, use chest compressions in an attempt to expel the obstructing agent � After 30 seconds of chest compressions, remove the obstructing object if you see it, attempt 2 breaths

It is important to realize that more than one technique is often required to clear obstruction � Finger sweep of the patient’s mouth only if a solid object is seen � It is recommended that suction be performed on newborns rather than giving them back blows or abdominal thrusts �

� in cases in which obstructive foreign bodies cannot be removed under direct visualization and aggressive ppv has failed, practitioners can try to push a subglottic foreign body beyond the carina.

SUCTIONING �A large-bore dental-type suction tip is the most effective in clearing vomitus from the upper airway because it is less likely to become obstructed by particulate matter

�A large-bore dental-type tip device, such as the HI-D Big Stick suction tip, should be readily available at the bedside during all emergency airway management

� Interposition of a suction trap close to the suction device prevents clogging of the tubing with particulate debris A trap that fits directly onto a tracheal tube has been described, and use of this device allows effective suctioning during intubation

� Do not exceed 15 seconds for suctioning intervals and administer supplemental O 2 before and after suctioning � When feasible, perform suctioning under direct vision or with the aid of the laryngoscope

� Patients who are unresponsive or apneic are usually easier to ventilate with a bag-mask device when an oropharyngeal airway is in place. � In the ED, patients who tolerate an oropharyngeal airway should probably be intubated

� Some clinicians use a nasopharyngeal airway to dilate the nasal passages for 20 to 30 minutes before nasotracheal intubation � The nasal airway is better tolerated by semiconscious patients and is less likely to induce vomiting in those with an intact gag refex

OXYGEN THERAPY � Resuscitate all patients in cardiac or respiratory arrest with 100% O 2. � indication for supplemental O 2 defned as a Pa. O 2 lower than 60 mm Hg or (Sa. O 2) less than 90%. � memory loss at (Pa. O 2) of 45 mm Hg, and loss of consciousness occurs at a Pa. O 2 of 30 mm Hg. � Chronically hypoxemic patients can adapt and function with a Pa. O 2 of 50 mm Hg or lower

INDICATIONS AND CONTRAINDICATIONS � tissue hypoxia � Shock state � Respiratory distress without documented arterial hypoxemia � acute MI � Administer 100% O 2 to patients with carbon monoxide poisoning

� Use caution when administering supplemental O 2 to hypoxic patients with (Pa. CO 2) higher than 40 mm Hg, but do not withhold it

� fear of oxygen toxicity should not prevent use of O 2 when there is an indication but should encourage to use minimum concentration of O 2 necessary to an sp. O 2 ≥ 94%( therapeutic goals)

OXYGEN DELIVERY DEVICES � High-flow delivery systems provide an FIO 2 that is relatively constant despite changes in the patient’s respiratory pattern � The Venturi mask is the high-flow delivery device that is most widely available

� minimizing changes in FIO 2 as the patient’s respiratory pattern changes � The mask is continuously flushed by the high flow of gas, which prevents the accumulation of exhaled gas in the mask

inspiratory flow rate for a resting adult is about 30 L/min, a rate matched by the total gas flow provided by the Venturi mask at all settings � A patient in respiratory distress may have an inspiratory flow rate of 50 to 100 L/min. � If inspiratory flow rate exceeds the total gas flow delivered by the mask, additional air will be entrained around the mask, and FIO 2 will decrease �

� Low-flow delivery devices provide gas flow that is less than the patient’s inspiratory flow rate. The difference between the patient’s inspiratory flow and the flow delivered by the device is met by a variable amount of room air being drawn into the system

� in simple mask complex interplay between mask volume, tidal volume, respiratory rate, and O 2 flow determines the FIO 2 delivered to the patient

�A partial rebreathing mask incorporates a bag-type reservoir to increase the amount of O 2 available during inspiration thereby requiring less outside air to be entrained

� Nonrebreathing masks are similar to partial rebreathing masks but have a series of oneway valves � One valve lies between the mask and the reservoir and prevents exhaled gas from entering the reservoir � Two valves in the side of the mask permit exhalation while preventing the entry of outside air

Many clinicians have the misconception that a non-rebreathing mask can provide an FIO 2 near 100%. � In practice, a non-rebreathing mask usually delivers an FIO 2 of about 70% �

� Highflow systems should generally be used for patients who need precise control of FIO 2, such as COPD patients with chronic respiratory acidosis

� An oxygen flow rate of 1 to 3 L/min by nasal cannula will result in an FIO 2 of 23% to 35%. Patients with signifcant hypoxemia, endorgan dysfunction, or respiratory distress require a higher FIO 2 delivery system

� An initial FIO 2 of 24% to 28% delivered by Venturi mask is indicated for patients with hypoxemia and chronic respiratory acidosis � Equilibration of Sa. O 2 after changes in supplemental O 2 occurs within 5 min

� FIO 2 should be titrated to achieve therapeutic goals while minimizing the risk for complications � An Sa. O 2 of 90% to 95% (Pa. O 2 ≈ 60 to 80 mm Hg) is an appropriate target

� In patients with COPD-associated hypercapnia, an Sa. O 2 of 90% (Pa. O 2 ≈ 60 mm Hg) should be the goal of O 2 therapy

PREOXYGENATION FOR RAPIDSEQUENCE INTUBATION � Preoxygenation is usually accomplished by providing the maximal FIO 2 with a nonrebreather mask for 3 to 5 min before intubation � Alternatively, eight vital capacity breaths from a maximal FIO 2 system, such as a nonrebreather mask or a bag-valve-mask device, is acceptable when there is no time for standard preoxygenation

� The purpose of preoxygenation is not just to maximize oxygen saturation but to wash out nitrogen from the patient’s lungs and replace it with oxygen � Morbidly obese patients are best preoxygenated in a 25 -degree head-up position

� Sometimes patients who need preoxygenation the most are uncooperative � These patients may beneft from delayedsequence intubation—careful to allow oxygenation with a face mask or NPPV for 2 to 3 min before administering a paralytic agent. � Ketamine (1 to 1. 5 mg/kg by slow intravenous push) has been suggested for this technique

� Another method to delay desaturation during RSI is nasopharyngeal oxygen insuffation during apnea Using a standard nasal cannula with a nasopharyngeal airway is simpler and would probably provide the same beneft � Also, it is important to keep the upper airway open by using a jaw thrust or artifcial airway for this technique to be most benefcial �

NASAL HIGH-FLOW OXYGEN � high-flow nasal oxygen is a relatively new concept that may have some utility for optimizing oxygenation in critically ill children and adults

BAG-MASK VENTILATION � Many authors note that BMV is relatively contraindicated in patients with a full stomach, those in cardiac arrest, and those undergoing RSI

� goal is to achieve adequate gas exchange while keeping peak airway pressure low � the best method of BMV is to provide a tidal volume of about 500 m. L delivered over a period of 1 to 1. 5 seconds

Generally, wellfitting intact dentures should be left in place to help ensure a better seal with the mask � it is important to remember to use oropharyngeal or nasopharyngeal airways (or both) whenever face mask ventilation is diffcult �

� All bag-mask devices should be attached to a supplemental O 2 source (with a flow rate of 15 L/min) to avoid hypoxia � A 2500 -m. L bag reservoir and a demand valve are preferred for O 2 supplementation during BMV

� A recent study showed that most patients with diffcult BMV became easier to ventilate after paralytic agents were administered and none were more diffcult to ventilate after paralytics

� Applying Sellick’s maneuver during BMV may further decrease the risk for gastric infation and is still recommended by most airway experts. � It should be noted that the routine use of cricoid pressure during BMV of patients in cardiac arrest is not recommended in the 2010 American Heart Association Guideline

� It is recommended that cricoid pressure be released immediately if there is any diffculty ventilating with a face mask in an emergency setting

EXTRAGLOTTIC AIRWAY DEVICES � EGAs can be divided into two groups, LMAs and retroglottic devices

LMAS � intubating LMA (ILMA) or a nonintubating LMA can be inserted in less than 30 seconds and provide effective ventilation in more than 98% of patients

failure to ventilate and oxygenate with the LMA occurs in about 6% of cases � Another 6% of patients with diffcult airways suffer episodes of hypoxia during attempts to intubate through the LMA. � There is evidence that ILMA performs better in cannot-intubate/cannot-ventilate situation. � Failure to ventilate with the ILMA occurs in only about 2% of cases, and hypoxia after ILMA placement is very rare �

� almost all patients can be adequately ventilated with the ILMA and 94% to 99% can be intubated through the device � When brisk bleeding above the glottis makes ventilation and intubation difficult, ILMA can prevent aspiration of blood and facilitate blind or fiberoptic intubation

� In patients requiring urgent cricothyrotomy or percutaneous needle insertion into the trachea the ILMA can be used to counteract anterior neck pressure � In this capacity, ILMA provides temporary ventilation and stabilizes the cervical spine during the surgical airway procedure

� ILMA is relatively contraindicated in awake patients, especially those with a full stomach � some evidence shows that ILMA causes posterior pressure on midportion of cervical spine � device is generally considered safe in patients with an unstable cervical spine injury

� Incorrect ILMA size is more likely to be a problem if the device is too small � If another ILMA size is not available, external anterior neck manipulation or downward pressure may bring the glottis and ILMA cuff into proper alignment

LMA CLASSIC

� best patient position for insertion of LMA is sniffng position, with neck flexed and head extended � Sometimes adjusting the patient’s head and neck position is easier than trying to change the position of the LMA if cuff seal

� sniffng position or into the chin-to-chest position � jaw -thrust or a chin-lift maneuver � anterior neck pressure to help manipulate glottis into improved contact with LMA mask

� withdraw, � � advance, or rotate LMA cuff completely remove If unsuccessful, change the size of the LMA. A larger LMA

COMPLICATIONS � aspiration of gastric contents and hypoxia � there is evidence that it provides some protection from passive regurgitation and produces less gastric infation than BMV does

RETROGLOTTIC AIRWAY DEVICES

� King LT has only one airway lumen and a simplifed cuff system, so both cuffs can be infated from a single port � tip of the King LT is designed to be placed in esophagus only

PLACEMENT OF THE KING LT � Size 3 is yellow and designed for patients 4 to 5 feet in height, size 4 is red and designed for patients 5 to 6 feet in height, and size 5 is purple and designed for patients taller than 6 feet

� best patient position for insertion is sniffng position, but it can be placed with the head in the neutral position if necessary

Introduce tip of device into corner of mouth while rotating the tube 45 to 90 degrees so that the blue orientation line on the tube is touching corner of the mouth � As the tip passes under the base of tongue, rotate the tube back to the midline so that blue orientation line faces the ceiling � Without exerting force, advance King LT until connector is aligned with teeth �

COMBITUBE AND EASYTUBE � The Combitube not recommended in patients shorter than 4 feet � It is contraindicated in patients with suspected caustic poisoning or proximal esophageal disorders

� The � Combitube is available in two sizes smaller 37 -Fr device for patients 4 feet to 5 feet 6 inches tall and the larger 41 -Fr device for patient taller than 5 feet 6 inches

� If resistance is met in the hypopharynx, remove tube and bend it between the balloons for several seconds to facilitate insertion. � After insertion, fill the pharyngeal balloon with 100 m. L of air and the distal cuff with 10 to 15 m. L of air

� Alternatively, use a Wee-type aspirator device on the shorter (clear) lumen to confirm that the tip is in the esophagus before ventilation through the longer (blue) lumen � If there is confusion about location of Combitube tip, use capnography to ensure that correct airway tube is being ventilated

� The Combitube must also be maintained in the true midline position during insertion to avoid blind pockets in supraglottic area

� Our goal should be to avoid RSI in patients who cannot be ventilated with a bag-mask device and cannot be intubated by direct or video laryngoscopy.

� if RSI is our usual method of intubation, we must be prepared to perform a surgical airway when laryngoscopy, BMV, and backup devices fail