In October 2003, following two years of planning, the acute NIV service, led by Professor Wedzicha, Professor of Respiratory medicine was introduced on Currie Ward at The Royal London. Non-invasive ventilation involves the delivery of pressurised gas flow through a tight-fitting mask, which helps patients breathe without the need for invasive intubation. Patients tend to recover more easily and more quickly than after full ventilation, which can further weaken patients who are already weak due to ill health. This method is also less emotionally invasive for both the patient and their friends and family, who are often distressed by full ventilation methods in an intensive care environment.

Respiratory failure is defined as a failure to maintain adequate gas exchange and is characterised by abnormalities in arterial blood gas tensions:

The use of NIV techniques in patients with type two respiratory failure has been found to reduce complications posed by invasive intubation and increased the treatment options for patients who may have otherwise been unsuitable or inappropriate for invasive techniques. Possible complications resulting from invasive intubation:

• Exposure to increase risk of infection;
• Laryngeal and tracheal injury;
• Decreased cardiac output;
• Aspiration;
• Tension pneumothorax;
• Bronchospasm;
• Sinusitis;
• Pneumonia.

Aims and methods of the NIV audit

The audit to evaluate the implementation and effectiveness of NIV on Currie Ward was devised by Dr Lloyd-Owen, Consultant in Respiratory medicine, based on the British Thoracic Society guidelines for management of NIV (2002) - see audit criteria.

The audit forms were available on Currie Ward between October 2003 and March 2004. It was the responsibility of both medical and nursing staff to complete the form. This was then taken out of the patients' notes and left in a central folder.

Patients were referred to the designated senior registrar or respiratory consultant and assessed for suitability for treatment.

During the audit period, 15 patients with COPD with first presentation, type two failure were referred for review. One patient with obesity-related hypoventilation was omitted from the figures, and a total of 14 patients were reviewed. The average age of patients was 73 years, within a range of 63 to 91 years. The majority of patients were male: nine men and six women.

Data collection

Complete data was available for ten patients, and incomplete data was available for a further three patients. Blood gas analysis information was available on all 14 patients. The data was incomplete due to the death of one of the patients and the transfer of a further two patients less than four hours after initiation of NIV. No data was available on two patients, one of whom was unable to tolerate NIV, the other person's set of notes was unavailable. However the data that was analysed revealed the following results.

Analysis of data

Dr Katherine Spinks, an SPR working with the respiratory consultants on the ward, examined the data.

Results

There was an overall improvement for most of the patients commenced on NIV:

In examining the six patients who died, it is noted that their Ph on commencing NIV was relatively lower and their PCO2 higher than those patients who tolerated and were successful on NIV.

Average CO2 changes  between those with good and poor outcomes

This indicates that these patients were given NIV where all other treatments have failed and the possibility of a poor outcome with NIV was high. The demographics of the patients who died were as follows:

• Older (mean age 73 years compared to 71)
• Five out of the six patients were not suitable for invasive ventilation.
• Four out of the six patients were drowsy and/or confused.
• One patient was not suitable for invasive ventilation, had hypotension, severe hypoxia and suffered a cardiac arrest six hours post initiation, despite initial improvement.
• One patient continued on NIV for more than one week, without significant improvement and then died.

The majority of referrals were made from Currie Ward: five in total. A further three referrals were made from Accident and Emergency. One patient was from a cardiac ward, and the other one was referred from a care of the elderly ward. Due to poor data collection, we were unable to identify the origin of referral for the other three patients.

The busiest time was December when six patients were ventilated. Two patients admitted into the service in October, November and January, with three in February. There were no patients in March and February, this may be because referrals were made out of hours and the patients involved were transferred to ITU or the London Chest Hospital, rather than being sent to Currie Ward.

Difficulty with data collection was one of the key problems to the accuracy of this audit and consequently not all of the audit criteria were met. This issue has been addressed and it highlighted to the nursing and medical staff involved with NIV the importance of completing the audit data to enable an accurate evaluation of the service. As a result, the audit forms have now been reviewed and have been copied onto a distinctive coloured paper to ensure that they are kept centrally and not filed in the patients care records folder. This change ensures that the forms are reviewed quickly, and any data omitted can be completed in a timely manner. We are aware that data was also not captured for referrals made to the respiratory registrar outside of the service hours. We are looking at ways to ensure that data is collected for all patients, including those who were sent to ITU or The London Chest Hospital due to lack of beds or referrals out of hours.

Lack of senior medical staff experienced in NIV can also pose problems out of hours. However, the respiratory SPR is contactable by phone to provide advice and ongoing management. The SPR will also review the patients at the weekend to assess patients on NIV.

Junior medical staff can take blood gases, but they are often unavailable or busy on other wards. Blood gases are key to the continuation of the treatment. We are currently reviewing where funding can be obtained for a C02 monitor which will ensure the patient is monitored closely and may reduce need for blood gas samples.

Nursing staff skills and confidence are building, and during the day they are supported by access to respiratory specialist nurses and physiotherapists, as well as experienced respiratory doctors.

In the initial stages of the implementation of NIV some patients experienced facial pressure sores due to ill-fitting masks. Following identification of the problem, a different model of mask has been found for use by NIV patients.

Currie Ward staff have completed training and competencies.

• Increase nurses competence and knowledge to enable the NIV service to be nurse led.
• Train nursing staff on how to take arterial blood gases.
• Establish a link with Accident and Emergency so that patients who meet the criteria for NIV following review by the respiratory team in A&E are referred to Currie Ward. A bed can then be prepared and a delegated nurse from the ward can attend A&E to commence NIV. This nurse can then ensure the speedy and safe transfer of the patient to the ward.
• Expand the service to four beds equipped to provide NIV on Currie Ward.

Thank you to Dr Simon Lloyd-Owen and Dr Katherine Spinks for examining the audit data.

References

2. Barts and The London NHS Trust. Ward based nasal ventilation at The Royal London Hospital: service description. Intranet.

5. Barr 2003.

6. Preston R. Introducing non-invasive positive pressure ventilation. Nursing Standard, 2001; 141(5) 26:42-5.

7. British Thoracic Society Standards of Care Committee. Non-invasive ventilation in acute respiratory failure. Thorax, 2002; 57:192-211.

Bibliography

Babu K, Chauhan A. non-invasive ventilation in chronic obstructive pulmonary disease. British Medical Journal, 2003;326: 177-8.

Gibbons D. Non-invasive positive ventilation for COPD patients. Professional Nurse, 2002;17.7: 405-8.