Chapter 12: Respiratory care, CPR and blood transfusion
Skip chapter table of contents and go to main content
Pre‐procedural considerations
Equipment
Non‐invasive ventilation devices
Non‐invasive devices provide a specific level of positive pressure during the respiratory cycle to prevent alveolar collapse and increase lung volume (Vargas et al. [278]). Devices that generate NIV support can broadly be divided into two categories:
- continuous flow with a continuous level of pressure (e.g. CPAP)
- variable flow with two levels of pressure (e.g. BiPAP).
It is recommended that settings are started at low pressures and titrated to physiological parameters, patient comfort and device synchronicity (Vadde and Pastores [277]).
Continuous positive airway pressure (CPAP)
In this mode, pressure is delivered at a constant level throughout the respiratory cycle through the use of a fixed or adjustable exhalation valve (known as a ‘PEEP valve’) (Figure 12.14). PEEP (positive end‐expiratory pressure) prevents alveoli from collapsing and thus increases lung diffusion area and gas exchange, and reduces the work of breathing (Roth et al. [238]).
Figure 12.14 Positive end‐expiratory pressure (PEEP) valves.
Bilevel positive airway pressure (BiPAP)
BiPAP devices provide two levels of support during the respiratory cycle. An inspiratory pressure (higher pressure) is delivered on inhalation (IPAP), while an expiratory pressure (lower pressure) is provided on exhalation (EPAP).
This mode of ventilation is a common choice for patients with hypercapnic respiratory failure, patients with COPD and patients with sleep disorders such as obstructive sleep apnoea (OSA). The upper airways are splinted and the respiratory muscles are assisted during inspiration, thereby reducing the work of breathing and dyspnoea (Demoule et al. [60], Stickle [264]).
Patients who use NIV in the long term for chronic conditions such as COPD and OSA will often have their own devices at home, which they can bring in with them if a stay in the acute setting is necessitated, for example in the presence of acute exacerbations of COPD (Davies et al. [56]). When NIV is used in conjunction with usual care, such as bronchodilators, there is an overall reduction in the likelihood of these patients requiring intubation by up to 50% (Stickle [264]).
Within the hospital setting, in the presence of an acute clinical presentation of respiratory compromise, BiPAP modes of ventilation are often delivered using mechanical ventilator devices that have the option of supporting invasive and non‐invasive modes, often within a critical care unit or high‐dependency unit.
NIV interface options
There are a variety of interfaces available for delivering NIV therapy, including nasal masks, face‐masks, full face‐masks (Figure 12.15) and helmets (Figure 12.16). The ideal interface should ensure a good seal to optimize effectiveness while maintaining patient comfort and compliance.
Figure 12.15 Non‐invasive ventilation (NIV) patient interfaces.
The first few hours of NIV are extremely important and continuous application is crucial in increasing the likelihood of success of NIV. Some of the issues that patients may experience include (Patel et al. [214]):
- discomfort
- pressure intolerance with difficulty exhaling
- air leaks
- claustrophobia
- skin breakdown (particularly over the bridge of the nose when using masks)
- upper airway dryness
- eye irritation.
Interface‐related problems are common reasons for poor adaptation and NIV intolerance. This can cause an increase in respiratory rate and minute volume, which can lead to poor synchronicity with the device (Spoletini and Hill [263]). Good nursing and multidisciplinary care are essential to improving interface tolerance.
Non‐invasive masks
Non‐invasive masks are made from a combination of a soft material (polyvinyl chloride, polypropylene, silicone, silicone elastomer or hydrogel) that forms the seal against the patient's face and a transparent mask made of polyvinyl chloride, polycarbonate or thermoplastic.
Unintentional leaks around the interface can interfere with the effectiveness of the therapy and cause irritation to the eyes. Most interfaces come with a fitting gauge to ensure correct sizing and minimize this issue. Other strategies include tightening the straps, adjusting the position of the mask, adjusting the volume of air in the mask and optimizing the patient's head position.
A certain amount of pressure is required when fitting the mask to keep it in place and form a seal (Brill [30]). Too much pressure can lead to discomfort, intolerance and skin integrity issues, particularly on the nasal bridge and ears. This can be minimized by ensuring the patient's skin is clean and dry, applying pressure‐relieving dressings and relieving the pressure of the mask, where possible.
Non‐invasive helmets
Non‐invasive helmets or hoods are transparent devices made from latex‐free polyvinyl chloride with a soft collar neck seal; they do not come in contact with the patient's face (Figure 12.16). Helmets have the advantage of avoiding skin integrity issues and improving patient comfort independent of face morphology (Liu et al. [136]). Patients are also able to drink freely, communicate and expectorate.
Figure 12.16 Non‐invasive ventilation (NIV) helmet.
CPAP
The set‐up and use of CPAP is described in Procedure guideline 12.3: Continuous positive airway pressure (CPAP). Its use should be considered only with a co‐operative patient who can maintain their airway and control secretions with an adequate cough reflex. The patient should be able to co‐ordinate their breathing with the ventilator and breathe unaided for several minutes if CPAP is delivered via a ventilator (Stickle [264]).
CPAP requires the following equipment:
- A ventilation device that can generate a flow of pressurized breathable gas and oxygen at variable rates – for example, Dräger's CPAP bellows (Figure 12.17), Breas Medical Ltd's NIPPY or Philips’ Respironics.
- A bacterial–viral filter (not a heat and moisture exchanger) (Figure 12.18). This filter provides protection against various particles including bacteria, viruses and water droplets. It also helps to protect the patient, the equipment and the breathing circuit from contamination.
- Ventilation device tubing. Consider active humidification if delivering NIV or CPAP through a face‐mask or nasal mask, to optimize mucocillary clearance.
- A CPAP mask (face‐mask or nasal mask) or CPAP helmet with securing straps (see Figures 12.15 and 12.16).
- A positive end‐expiratory pressure (PEEP) valve of the prescribed level. Available fixed PEEP valves range from 5 cmH2O to 20 cmH2O (see Figure 12.14).
Figure 12.17 Continuous positive airway pressure (CPAP) bellows.
Figure 12.18 Bacterial–viral filter.
Figure 12.19 Nasopharyngeal airway and safety pin.
Assessment and recording tools
While a patient is on CPAP, it is essential to monitor their respiratory rate, cardiovascular status (blood pressure and heart rate), pulse oximetry (SpO2) and fluid balance at least hourly. It is also vital to carry out regular arterial blood gas (ABG) sampling.
Clinical features that should be assessed are:
- chest wall movement
- co‐ordination of respiratory effort with the ventilator
- accessory muscle recruitment
- general assessment – whether the patient is sweating, clammy or dyspnoeic
- auscultation of the chest for air entry and additional breath sounds
- patient comfort
- neurological status – signs of confusion or tiredness.
Although patients may need a few hours of therapy to achieve the full benefit, there should be a noticeable improvement in the above physiological parameters within 2 hours if the NIV (in this case CPAP) is likely to be effective (Cortegiani et al. [51], Davison et al. [57]). If there is no improvement within 2–4 hours, NIV should be discontinued and invasive ventilation considered.
Pharmacological support
Depending on the clinical presentation necessitating the use of NIV or CPAP, and also the patient's ability to tolerate the chosen interface, pharmacological support may increase the success rate of NIV management:
- Diuretics may be given if pulmonary oedema is present (Schnell et al. [245]).
- Bronchodialators may be given in patients with COPD or asthma, or in the presence of acute respiratory distress (Masa et al. [148]).
- Antimicrobials may be given if patients have suspected or confirmed clinical indicators of a respiratory infection (Masa et al. [148]).
- Steroids may be given in patients with acute or chronic exacerbations of COPD (Olivieri et al. [210]).
- In some cases, small doses of sedatives or anxiolytics may be a valuable option if patients are overly distressed, tachypnoeic, uncomfortable or experiencing claustrophobia that may lead them to refuse ongoing NIV or CPAP despite adequate explanation and reassurance (Hilbert et al. [109]). This must be done with caution as it may lead to loss of airway protection and/or depression of respiratory drive. Therefore, this will require increased levels of monitoring to ensure patient safety and may warrant transferring the patient to a critical care or high‐dependency area (Liu et al. [136]).
Non‐pharmacological support
There are a number of measures that can be initiated to help support patients during the use of NIV, such as:
- For some patients, the presence of a relative, a nurse or another healthcare professional may help to relieve the distress caused by NIV or CPAP.
- Optimizing patient positioning in bed by sitting the patient upright or in a semi‐recumbent position to at least 30° can relieve the symptoms of breathlessness (Corrêa et al. [50]).
- It is important to ensure the most favourable type, size and fit of the chosen interface (Hilbert et al. [109]).
- If appropriate and clinically feasible, patients can be offered a break from the chosen interface by switching them to an alternative level of respiratory support, such as high‐flow oxygen therapy (Brill [30]).
- Ensuring the trigger sensitivity, pressurization level and compatibility of the device tubing are appropriate will optimize synchronicity (Brill [30]).
Specific patient preparation
Education
CPAP can cause distress to patients, especially due to the tight‐fitting mask, while the hood can seem claustrophobic. If possible, a clear and concise description of how the therapy works should be provided either verbally or via an information leaflet. Time spent fitting the interface and building the patient's confidence is well invested (Brill [30]). As with any procedure, consent needs to be gained before treatment can commence. Allow time for the patient to express any concerns or fears they have regarding treatment. Acutely hypoxic patients may not comprehend the relevance of the therapy and so it should be explained to their relatives or carers so they can reassure the patient.
Procedure guideline 12.3
Continuous positive airway pressure (CPAP)
Table 12.9 Prevention and resolution (Procedure guideline 12.3)
| Problem | Cause | Prevention | Action |
|---|---|---|---|
| Airway is not maintained | Deteriorating respiratory or neurological function and/or the patient is tiring |
Use NEWS scoring to identify deterioration early.
Insert a nasopharyngeal airway (Figure 12.19). | Regular monitoring of respiratory function including skin colour, breathing pattern, respiratory rate, oxygen saturation and blood gases. Discuss changes with medical or anaesthetic staff. |
| Aspiration | Inability to maintain own airway | Request speech and language therapy (SLT) assessment. | Observe and assess the patient closely. After discussion with medical staff, a nasogastric tube may be inserted to reduce gastric distension. |
| Continuous pressure from the CPAP system can lead to insufflation of air into the stomach, causing aspiration |
Keep the patient nil by mouth and insert a nasogastric tube. | As above. | |
| Mask or helmet incorrectly sealed | Incorrect size of mask or helmet | Use appropriate size of mask or helmet. |
Alter mask or helmet position to correct the issue and ensure comfort.
Ensure the mask or helmet is the correct size.
Alter the position to ensure a correct seal. |
| Helmet not inflating or patient finding it difficult to breathe with mask |
Disconnection of tubing
Not connected to piped oxygen |
Switch on all audible alarms on equipment.
Clarify alarm parameters with medical or senior nursing staff.
Keep bed space tidy and free from clutter.
If possible, ensure bed space is close to or visible from the nurse station. |
Ensure a nurse is present with the patient at all times.
Observe the patient and CPAP system closely to ensure the equipment is working optimally and that there is no failure of the system. |
| Eyes are dry or sore, or patient develops conjunctival oedema (all three issues only apply to face‐mask CPAP) |
Air leak from mask
High‐flow oxygen causing the eyes to dry out
Facial pressure from mask causing oedema | Protect eyes from drying out. Use correct size of mask or helmet for patient. |
Ensure the mask or helmet is well sealed with no leaks.
Apply pressure‐relieving padding around the mask.
Carry out regular eye care (see Chapter c09: Patient comfort and supporting personal hygiene).
Adjust the mask to the patient's facial contours.
Alter and position the mask as comfortably as possible.
Position padding around the head strap to relieve pressure. |
| Dry mouth | CPAP system uses a very high oxygen flow, which has a drying effect | Provide adequate oral hydration. |
Carry out regular mouth care.
Give the patient regular sips of water, ice to suck or drinks (as much as the patient is able to take).
Humidify the oxygen if using a face‐mask. |
| Non‐compliance with CPAP equipment | Anxiety | Calm, informative communication. |
Inform the patient of any changes taking place.
Communicate with the patient's family, keep them informed and involve them in care and communication with the patient.
Inform the doctor of the patient's anxiety level.
Administer prescribed anxiolytic agent if required. |
| Inability to eat |
Gastric distension due to CPAP
Loss of appetite
Distress caused by respiratory status and CPAP
Nausea and vomiting | Provide small but regular easily managed (soft) oral diet or supplement drinks. |
Encourage dietary intake and oral supplementary fluids. If patient is unable to take these orally, refer to dietician as an alternative method of feeding may be considered, for example enteral feeding via nasogastric or jejunal tube or intravenous feeding (parenteral nutrition).
Administer an antiemetic.
Encourage and reassure the patient. |
| Inability to communicate effectively | Mask or helmet restriction. | Provide means of non‐verbal communication. | Reassure the patient and ensure they are comfortable. |
| Feelings of isolation | Ask a relative, carer or healthcare assistant to stay with the patient. |
Encourage the patient to communicate, and explain how they can use non‐verbal means of communicating (e.g. letter board, tablets).
Reassure the patient. |
