Care of the intubated patient in the PACU: the 'ABCDE' approach.
This paper discusses airway management in the post anaesthetic care
unit (PACU). Many patients will be extubated on arrival to the PACU,
however a small number will need further support with tracheal
intubation. Patient assessment is a key role for the PACU staff and
using the ABCDE approach will provide a systematic method for assessing
the patient and determining suitability for extubation. Care of the
patient following extubation is also described.
KEYWORDS Airway management / Extubation / Post anaesthetic care unit / Recovery room / Tracheal tube
Airway obstruction (Medicine)
(Care and treatment)
Airway obstruction (Medicine) (Research)
Anesthesia (Health aspects)
Patients (Care and treatment)
Patients (Health aspects)
|Publication:||Name: Journal of Perioperative Practice Publisher: Association for Perioperative Practice Audience: Academic Format: Magazine/Journal Subject: Health; Health care industry Copyright: COPYRIGHT 2008 Association for Perioperative Practice ISSN: 1750-4589|
|Issue:||Date: March, 2008 Source Volume: 18 Source Issue: 3|
|Topic:||Event Code: 310 Science & research|
|Geographic:||Geographic Scope: United Kingdom Geographic Code: 4EUUK United Kingdom|
Most patients will spend time in the PACU following surgery until they are stable enough to return to a ward. Monitoring is an essential part of PACU care. This paper has adopted the systematic 'ABCDE' approach to assessment specifically to patients recovering from surgery. Criteria for extubation are also discussed along with a description of care of the extubated patient.
Airway management in the PACU
Recovery from anaesthesia begins at the end of surgery and continues until the patient has recovered sufficiently from their surgery and anaesthesia to return to normal function. The time taken for patient recovery depends on the patient's condition, the type of surgery and the anaesthetic technique used. During the initial period after surgery, most patients are monitored in the PACU until they meet discharge criteria to return to a ward.
Current practice in the UK is to remove the tracheal tube (extubation) with the patient deeply anaesthetised or awake in the operating theatre before transfer to the PACU. Patients who have a laryngeal mask airway (LMA) will usually have it in place when they arrive in the PACU. There may be a small number of patients who require further support from tracheal intubation with a tracheal tube in the PACU. There may also be a small number of patients who are critically ill and require an extended period of intubation and mechanical ventilation in the PACU with appropriately trained staff or in an intensive care unit (ICU) or high dependency unit (HDU).
The Association of Anaesthetists of Great Britain & Ireland states that these patients should be closely monitored and extubated when they have a clear airway, cardiovascular stability and the ability to communicate. The anaesthetist is responsible for the removal of tracheal tubes (AAGBI 2002).
Monitoring and care of the intubated patient
The 'ABCDE' system of assessment and treatment of the critically ill patient has been described in the ALERT course and is widely used in immediate and advanced life support training (Smith et al 2002). It is appropriate to use this system when assessing the patient in PACU and determining suitability for extubation.
Airway obstruction leads to hypoxia and if untreated can cause damage to the brain, heart and kidneys and lead to cardiac arrest (Nolan et al 2005). The main reason for airway obstruction in the PACU is central nervous system depression from drugs (opioids, general anaesthetic agents). Bleeding (for example, after tonsillectomy) can also put patients at risk from airway obstruction. Patients at high risk of partial or complete obstruction should not have their tracheal tube or LMA removed until they are able to maintain an open airway. These patients will also require supplementary oxygen to maintain sufficient arterial oxygen saturation.
Patient assessment should include level of consciousness, arterial oxygen saturation and respiratory rate along with other observations that will be discussed later. The patient must be judged to be able to maintain an open airway and breathe without assistance prior to extubation. The awake patient will have return of respiratory and laryngeal reflexes and this will help to protect the airway.
Breathing problems cause insufficient oxygenation of the blood and may eventually lead to cardiac arrest if untreated. Breathing inadequacy may occur as a result of problems with respiratory drive, respiratory effort or lung disorders. Common breathing problems postoperatively include central nervous system depression (opioids, general anaesthetic agents) and inadequate reversal of neuromuscular blockade. Patients may also have underlying pulmonary disease that impairs breathing and prolongs the post anaesthesia recovery period. The primary treatment for breathing problems is oxygen therapy. Patients may also require further support with mechanical ventilation (Nolan et al 2005, Carbery 2008).
Patient assessment should include level of consciousness, pulse oximetry and respiratory rate. A fast respiratory rate (>30 [min.sup.-1]) is an early indication of breathing problems (McBride et al 2005). Pulse oximetry gives an indication of arterial oxygen saturation, but an arterial blood gas will provide further information about ventilation including pH and partial pressure of carbon dioxide (pC[O.sub.2]). Breathing inadequacy leads to rising pC[O.sub.2] (hypercapnia) and decreasing pH (respiratory acidosis). The patient's level of consciousness may be altered by hypoxia or hypercapnia. It is important to provide ventilatory support until the arterial blood gases are normal and the patient is able to breathe spontaneously. Table 1 gives normal arterial blood gas values.
Circulation problems may be caused by primary heart disease such as myocardial infarction, heart block and some drugs. The most common cause of cardiac arrest is an arrhythmia caused by myocardial ischaemia or infarction. Circulation problems may also be the result of heart abnormalities secondary to other problems such as airway obstruction or apnoea, tension pneumothorax or severe blood loss. Cardiac function will also be impaired in hypothermia, severe septic shock, hypoxia and anaemia. The most common circulation problem in the surgical setting is hypovolaemia caused by bleeding and should be considered the primary cause of shock until proven otherwise (Nolan et al 2005).
Routine patient assessment should always include heart rate and blood pressure. A rapid or rising heart rate (>100 [min.sup.-1]) and low or falling blood pressure (<90mmHg systolic) are indicators of hypovolaemia or shock (Buist et al 2004). Further cardiovascular assessment will help to establish cardiovascular stability and suitability for extubation. Measurement of capillary refill time (CRT) gives an indication of peripheral perfusion. A CRT of greater than two seconds suggests poor peripheral perfusion. The extremities may also be cool, pale or mottled when perfusion is decreased. Other signs of poor cardiac output include reduced level of consciousness and oliguria (urine volume <0.5[ml.sup.-1] [hour.sup.-1]). It is also crucial to assess the patient for any signs of external or internal bleeding depending on the type of surgery. Bleeding into the thorax, abdomen or pelvis may be significant even if drains appear to be empty. Impaired circulation due to hypovolaemia should be treated immediately with fluid administration. Colloids (for example, gelofusine) or crystalloids (for example, Hartmann's solution; Sodium hydrochloride 0.9%) may be used (Perel & Roberts 1997). Local guidelines for fluid administration should be followed. Patients with ongoing bleeding will not respond or only transiently respond to a fluid bolus. The patient may need to return to the theatre to correct bleeding problems.
The patient should also be assessed and treated appropriately for hypertension and arrhythmias. Postoperative pain and bladder distension may be causes of hypertension and should be considered. Removal of the artificial airway should only be considered once cardiovascular stability has been achieved.
Changes in level of consciousness can be caused by hypoxia, hypercapnia or cerebral hypoperfusion (i.e. airway, breathing and circulation problems). While all of these may potentially make the patient in the PACU unconscious, the most common cause is the residual effects of sedatives, analgesics and general anaesthetic agents.
Patients are often extubated before fully regaining consciousness, but they must be able to maintain an open airway and breathe spontaneously. It may be beneficial to place the patient in the lateral recovery position (see Figure 1) to encourage a clear airway and drainage of secretions, blood or vomitus (Yentis et al 2004).
A rapid method of assessing the patient's conscious level is 'AVPU':
A--The patient is awake and alert
V--The patient responds to vocal stimuli
P--The patient responds to painful stimuli
U--Unresponsive to all stimuli.
The Glasgow Coma Scale is also a useful tool in assessing level of consciousness.
Other factors to consider when assessing the patient include temperature, control of nausea and vomiting, adequate postoperative analgesia and movement of extremities. It may be necessary to warm the patient, control shivering, offer analgesia or reverse paralysis before the patient can be considered for extubation (Yentis et al 2004).
Criteria for extubation
Tracheal extubation is generally performed by an anaesthetist in the PACU. The Association of Anaesthetists of Great Britain & Ireland recommends continuous one-to-one observation by appropriately trained staff until the patient is able to maintain their own airway (AAGBI 2005). Assessing the patient for extubation suitability requires ongoing 'ABCDE' assessment until the patient meets the criteria for extubation. At a basic level, extubation criteria includes an awake, responsive patient able to maintain adequate spontaneous ventilation and gas exchange who has cardiovascular stability and reversal of paralysis. Cardiovascular stability includes adequate circulation and respiratory gas transport systemically and through the lungs as well as sufficient haemoglobin levels for carrying oxygen (Miller et al 1995). There are other variables that will determine patient readiness for removal of a tracheal tube or laryngeal mask airway. The type and length of surgery will impact readiness for extubation. For example, straightforward orthopaedic procedures may have short operation times and patients will be extubated before coming to the PACU, while longer and more complicated operations (for example, coronary artery bypass grafting, liver transplantation, major abdominal surgery) will require haemodynamic stabilisation and therefore a prolonged period of intubation. Some operations (for example, ear, nose, throat) put the airway at risk and it is important to leave the tube in place to protect the patient's airway. The patient's age, general level of health and preoperative condition will impact recovery from an anaesthetic and length of time required for ongoing airway and ventilation support after an operation.
[FIGURE 1 OMITTED]
There are no specific extubation criteria used nationally for patients in the PACU. However, hospitals may have local guidelines or criteria and these should be followed where available. If no local guidelines for extubation are available, the decision to extubate should be based on thorough patient assessment, good communication with the anaesthesia team, proper documentation and sound clinical judgement.
Care of the patient following extubation
Extubation is the goal for all patients who have been intubated and ventilated for any length of time. Care of the patient following extubation will be the same whether the patient is extubated immediately following surgery or after a prolonged period of intubation in the PACU or ICU. The Association of Anaesthetists of Great Britain & Ireland guidelines state that an appropriately trained PACU nurse may remove the LMA. The tracheal tube should be removed by an anaesthetist (AAGBI 2002). Several problems can occur during extubation, therefore it is important patients are closely monitored until ready for discharge.
Any form of airway dysfunction following extubation may be life-threatening and requires immediate intervention. Laryngospasm is most commonly caused by a reaction to a foreign body such as blood or saliva near the glottis and will result in the patient having difficulty with breathing and maintaining adequate oxygenation (Miller et al 1995). Reintubation may be necessary and airway equipment for tracheal intubation should be readily available before extubation. Laryngospasm in the waking patient usually resolves with simple airway manoeuvres without the need for reintubation. If the patient is not fully awake and not responding to simple airway manoeuvres, high flow oxygen and continuous positive airway pressure (CPAP) may be used (Visvanthan et al 2005). It may be necessary to sedate and paralyze the patient in preparation for reintubation.
Coughing frequently happens during extubation. While coughing generally resolves without further intervention, it is important to be aware of the potential associated problems (for example, raised intrathoracic, intraocular, intra-abdominal or intracranial pressure) (Miller et al 1995).
Other possible causes of airway obstruction following extubation include airway muscle relaxation, soft tissue oedema and foreign body aspiration. The key is to recognise signs of airway obstruction. Partial airway obstruction may present as difficulty breathing, choking, patient distress, noisy breathing (stridor or wheezing). Complete airway obstruction will be silent with no air movement at the patient's mouth. The patient's attempts at breathing will be strenuous with use of accessory muscles and a 'see-saw' pattern where the chest and abdomen are moving asynchronously with each attempted breath.
A few interventions prior to and during extubation may help prevent airway problems (Miller et al 1995). Suctioning the patient's pharynx and larynx prior to removing the tube will help to clear secretions that might otherwise be inhaled. Placing the patient in a lateral or sitting up position will help maintain an open airway. The lungs should be inflated with oxygen immediately before and during extubation to help clear secretions from the larynx and provide an oxygen reserve in the event of laryngospasm.
Immediate action with any airway problem includes providing high concentration oxygen using a mask and opening the airway with a good jaw thrust manoeuvre which lifts the soft palate away from the posterior pharyngeal wall. A correctly sized oropharyngeal airway (Guedel airway) may be used in the deeply sedated patient to help maintain an open airway. This will need to be removed when the patient is awake. In the event of larygnospasm, continuous positive airway pressure (CPAP) may be used to support the airway until the laryngospasm resolves.
Extubation can cause small and transient rises in blood pressure and heart rate that last 5-15 minutes (Miller et al 2005). For most patients this will not be a problem and in some cases may be helpful if blood pressure is low following administration of certain medicines. However, a small number of patients with heart disease or other cardiac problems may be affected by these changes. Heart rate and blood pressure should be monitored frequently during and after extubation with appropriate intervention as required.
Aspiration of gastric content
Aspiration of gastric content is potentially a risk in patients who are anaesthetised due to a decrease in the tone of the lower oesophageal sphincter and depressed laryngeal reflexes (Ng & Smith 2001). Measures to prevent aspiration include an empty stomach, administration of medicines to increase lower oesophageal sphincter tone and induction of anaesthesia with the patient in the lateral or sitting position (Ng & Smith 2001). In the event of aspiration, the patient should initially be positioned laterally with the head down to prevent gastric contents entering the lungs. Oxygen should be given and the pharynx and larynx suctioned to remove debris. The patient may need to be reintubated to protect the airway and provide a route for tracheobronchial suctioning.
Patient monitoring following extubation should continue until the patient is ready for discharge to a ward or other clinical area. Table 2 provides information that should be collected and recorded.
Preparing for discharge
All PACUs should have clearly defined discharge criteria for the patient to the general ward or other clinical areas (AAGBI 2002). PACU staff may make the decision to discharge the patient from the unit once all the criteria have been met. Discharge criteria should include full consciousness with minimal stimulation, ability to maintain a clear airway, adequate breathing and circulation, acceptable postoperative control of pain and emesis, stable temperature and oxygen and intravenous therapy prescribed where appropriate (AAGBI 2002) (Table 3). Any patient who does not fully meet the criteria must stay in the unit and the anaesthetist should be informed. Some patients may need further support and monitoring in the ICU or HDU if they do not meet the criteria. The PACU nurse is responsible for an accurate and thorough handover to ward staff. Any problems with the anaesthetic, operation or recovery period should be described along with any medications and infusion device settings. Good communication with the anaesthesia team and ward staff will facilitate a quality recovery for the patient.
Airway management is an important part of successful recovery in the PACU. The 'ABCDE' approach to assessment provides a systematic method for assessing patients to determine suitability for tracheal extubation as well as care following removal of the tracheal tube.
Provenance and Peer review: Commissioned by the Editor; Peer reviewed.
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Correspondence address: Jackie Younker, Senior Lecturer in Nursing, University of the West of England, 7 Grove Park, Redland, Bristol, BS6 6PP.
Senior Lecturer in Nursing, University of the West of England
Table 1 Arterial blood gas normal values pH 7.35-7.45 P[O.sub.2] 10-13.3 kPa (75-100mmHg) PC[O.sub.2] 4.8-6.1 kPa (35-45mmHg) Base Deficit [+ or -] 2.5 Plasma HC[O.sub.2] 22-26mmol/L [O.sub.2] saturation 95-100% Adapted from: Kumar P, Clark M 2005 Clinical Medicine (6th Edition) London, Elsevier Saunders Table 2 Required information for recording in PACU * Level of consciousness * Oxygen administration * Oxygen saturation (pulse oximetry) * Blood pressure * Heart rate and rhythm * Respiratory rate * Level of pain * IV infusions * Medicines given * Also consider recording temperature, urinary output, central venous pressure, end-tidal C[O.sub.2] and surgical drainage as necessary Adapted from: The Association of Anaesthetists of Great Britain & Ireland 2002 Immediate Postanaesthetic Recovery London, The Association of Anaesthetists of Great Britain & Ireland Table 3 Discharge Criteria for PACU * Fully conscious without excessive stimulation * Able to maintain a clear airway * Respiratory and oxygenation satisfactory * Cardiovascular stability with no unexplained cardiac irregularity or persistent bleeding * Pulse and blood pressure should be close to normal pre-operative values * Adequate peripheral perfusion * Pain and emesis controlled with analgesic and anti-emetic regimens prescribed * Temperature within normal limits * Oxygen and IV therapy prescriptions as appropriate Adapted from: The Association of Anaesthetists of Great Britain & Ireland 2002 Immediate Postanaesthetic Recovery London, The Association of Anaesthetists of Great Britain & Ireland
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