Page 686 - ACCCN's Critical Care Nursing

Resuscitation 663

Advanced Airway Management used with either the face mask or other adjunct airway
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A person with signs of acute respiratory distress should devices such as LMA, Combitube or ETT. Having noted
be administered oxygen at the highest possible concen- this, there is currently no evidence to suggest that the use
tration. Initially during CPR, whenever possible, admin- of automated ventilators during cardiac arrest are more
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ister the highest possible oxygen concentration. Oxygen beneficial than bag–valve–mask devices.
should never be withheld for fear of adverse effects, as Rhythm
rescue breaths provide an inspired oxygen concentration There is an association between the initial cardiac arrhyth-
of only 15–18%. The administration of oxygen alone mias and survival to discharge after SCA. Cardiac arrest
does not result in adequate ventilation, and as such the rhythms can be divided into two subsets:
establishment of an effective airway is paramount. Airway
management is essential in the performance of CPR, and 1. ventricular fibrillation (VF) and pulseless ventricu-
may be administered using a variety of techniques. The lar tachycardia (VT)
choice of advanced airway adjunct is determined by the 2. non-VF/VT incorporating asystole and pulseless
availability of equipment and experienced personnel (see electrical activity (PEA).
Table 24.6 and Chapter 15): The most common arrhythmias observed in SCA are
l oropharyngeal (Guedel’s) airway pulseless VT and VF, with 60–85% of all patients initially
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l nasopharyngeal airway presenting with these lethal arrhythmias. PEA occurs as
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l laryngeal mask airway the initial rhythm in approximately 13–22% of cases;
l oesophageal–tracheal Combitube when witnessed by emergency personnel in the prehos-
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l endotracheal intubation pital setting, it has been documented as high as 50%.
l tracheostomy. Asystole is the most common arrest arrhythmia in chil-
dren, because their hearts respond to prolonged severe
While endotracheal tube (ETT) is considered the ‘gold hypoxia and acidosis by progressive bradycardia leading
standard’ for airway management in a cardiac arrest, as it to asystole. 53
protects the airway, assists effective ventilation, ensures
delivery of high concentrations of oxygen and eases suc- Ventricular fibrillation and pulseless
tioning, no studies have found that ETT use during a cardiac ventricular tachycardia
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arrest increases survival. It is vital that CPR not be inter- As previously noted, the only intervention shown to
rupted for more than 10 seconds during attempts at endo- unequivocally improve long-term survival after a VF or
tracheal intubation. Waveform capnography should be pulseless VT arrest is prompt and effective BLS, uninter-
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applied to confirm the ETT placement. The ETCO 2 may rupted chest compressions and early defibrillation. VT
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also be used to monitor the quality of the CPR. Given the and VF rhythms are displayed in Figures 24.5 and 24.6.
limitations noted in Table 24.6, a variety of adjunct airway/ Energy levels and subsequent shocks are equivalent for
ventilation management devices, such as bag–mask ven- both VF and pulseless VT.
tilation (BMV) and supraglottic airway devices (SADs)
such as laryngeal mask airway (LMA), the classic laryngeal Non-VF/VT
mask airway (cLMA), the oesophageal–tracheal Combi- Non-VF/VT arrhythmias include pulseless electrical activ-
tube (ETC) and the I-gel are available. When an LMA- ity and asystole. Pulseless electrical activity (PEA) or elec-
Fasttrach is in place, it can be used to guide the passage of tromechanical dissociation (EMD) reflects a dissociation
bougies, introducers, a bronchoscope or an ETT into the between the heart’s electrical and mechanical activities,
trachea. The benefit of the SADs is that they are easily and the two terms are used interchangeably. It is impor-
inserted without interruption to chest compressions. tant to note that PEA/EMD may present as any rhythm
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Currently, there is no evidence to support the routine use normally compatible with a pulse (e.g. sinus rhythm,
of any particular advanced adjunct airway devices. Health- sinus tachycardia/bradycardia). PEA is characterised by a
care professionals trained to use supraglottic airway stroke volume insufficient to produce a palpable pulse,
devices (e.g. LMA) may consider their use for airway man- despite adequate electrical activity. PEA often follows
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agement during cardiac arrest and as a backup or rescue defibrillation of VF and has a survival rate of 0–6%.
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airway in a difficult or failed tracheal intubation. Management of PEA includes identifying and correcting
Once an airway has been established, continue chest com- reversible causes, summarised as the 4 Hs and 4 Ts in
pressions without interruption for ventilation. Ventilate the Table 24.7.
lungs at a rate of approximately 10 breaths a minute and an Careful confirmation of asystole (see Figure 24.7) on two
inspiratory time of 1 sec with sufficient volume to produce leads and the absence of a palpable pulse are essential
a normal chest rise. Ventilation adjuncts may include: when making the decision to manage asystole. When an
l a simple face mask with filter and oxygen connector out-of-hospital arrest has an initial rhythm of asystole,
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(preintubation) survival to discharge is as low as 2%.
l bag–valve–mask systems Medications Administered During
l ventilators. Cardiac Arrest
If available, automated ventilators can be used. These Resuscitation drugs can be administered during a cardiac
may be set to deliver a tidal volume of 6–7 mL/kg at a arrest using a variety of routes including peripheral and
rate of 10 breaths/min. The automated ventilator may be central veins, or intraosseous (IO). Administration by the