Type 2 Respiratory Failure Research Articles

P117 Changes in prescription of home non-invasive ventilation (NIV) in Southern Adelaide Local Health Network (SALHN) from 2016 – 2020

Abstract Background Long term NIV is established therapy for patients with chronic type 2 respiratory failure (T2RF) due to neuromuscular disorders and obesity hypoventilation syndrome (OHS) without significant OSA. There is emerging evidence that COPD patients with T2RF also benefit from NIV. In our centre, there appears to be an increase in the prescription of long term NIV to patients over time, with 60% of all active long term NIV patients commencing therapy from 2017 onwards. In this study we will determine if (i) there has been increased provision of long term NIV to ward patients recovering from acute T2RF, (ii) there has been an increase in patients with COPD and T2RF commenced on long term NIV, (iii) there are patients with OHS and comorbid OSA who can be changed from NIV to CPAP and (iv) there is adequate follow up for patients who initiated NIV in the ward acutely. Methods Retrospective, observational study using a pre-existing database of all current and previous patients commenced on NIV from July 2016 to July 2020. Progress to date All active long term NIV patients have been identified and a database (n= 220) created containing all relevant information including date and place of NIV initiation and indication. Intended outcome and impact This audit will objectively assess the growth of our NIV service to facilitate better allocation of resources. It will also determine if our commencement and management of those on long term NIV is aligned with current evidence and best practice guidelines.

Predictors of success and failure of non-invasive ventilation use in type-2 respiratory failure

BackgroundNon-invasive ventilation is widely used now a days in patients with hypercapnic respiratory failure. Non-invasive ventilation can be used in Intensive Care Unit setting and wards provided trained staff is there to monitor. MethodsThis was a prospective observational study of 100 adult patients who were admitted with hypercapnic respiratory failure. Demographic information such as Age, Sex were recorded. Clinical parameters like Respiratory Rate, Heart Rate, Oxygen saturation and Arterial Blood Gas variables like pH, PaCO2, HCO3 were measured at the time of admission and at 1st hour, 4 hours and 24 hours after start of non-invasive ventilation. Outcome was recorded as success and failure with Non invasive ventilation. ResultsOut of 100 patients, 76 (76%) managed successfully with non-invasive ventilation and 24 patients (24%) needed intubation and invasive mechanical ventilation in this study. Majority of patients (76%) were with clinical diagnosis of Chronic Obstructive Pulmonary Disease. Respiratory Rate and Heart Rate were significantly lower and showed significant improvement at 1st hour, 4 hours and 24 hours in patients who successfully improved with Non invasive ventilation. Oxygen saturation was found to be significantly higher among patients successfully managed with Non invasive ventilation (84.35 ± 8.55 vs 76.87 ± 7.33) as compared to patients who required intubation. pH was found to be significantly higher (7.28 ± 0.06 vs 7.23 ± 0.05) in patients showing good response to Non invasive ventilation and improvement in pH at 1st hour, 4 hours and 24 hours was observed in patients successfully managed with Non invasive ventilation. PaCO2 level was found to be significantly lower and significant improvement in PaCO2 at 1st hour, 4 hours and 24 hours was seen in patients with Non invasive ventilation success. ConclusionImprovement in clinical parameters like respiratory rate, heart rate, Oxygen saturation and improvement in ABG variables like pH, PaCO2 after 1st and 4 hours of start of Non invasive ventilation and maintaining the improvement at 24 hours are predictors of success of non-invasive ventilation in hypercapnic patients.

Comparison of Simultaneous Capillary Blood Gases and End-Tidal Carbon Dioxide in Mechanically Ventilated Pediatric Patients with Acute Respiratory Failure.

In the follow-up of ventilation, invasive blood gas analysis and noninvasive monitoring of end-tidal carbon dioxide (ETCO 2 ) are used. We aimed to investigate the relationship between capillary partial pressure of carbon dioxide (PcCO 2 ) levels and ETCO 2 and also to investigate ETCO 2 's predictive feature of PcCO 2 levels. This study included 28 female and 30 male pediatric patients; 28 patients were type-1 respiratory failure (RF), 16 patients were acute respiratory distress syndrome, and 14 patients were type-2 RF. Our results showed a significant correlation between ETCO 2 and PcCO 2 . Although the strength of the correlation was weak throughout the measurements, the strength of this correlation increased significantly in type-2 RF.

Role of venous blood gases in hypercapnic respiratory failure chronic obstructive pulmonary disease patients presenting to the emergency department.

Many patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have type 2 respiratory failure (T2RF). Often arterial blood gases are not performed and correlation with venous blood gases (VBG) is controversial. The venous pH and bicarbonate (HCO3 ) are useful, but VBG pCO2 (PvCO2 ) is considered too unpredictable. To examine the utility of VBG in this cohort of patients. A prospective study of AECOPD patients with T2RF presenting to the emergency department was performed. Patients being considered for non-invasive ventilation and who required an arterial blood gas were invited to participate. A subsequent VBG was also taken, and Bland-Altman plots were used for analysis. Sixty-three patients were included in this study. The limits of agreement for pH and HCO3 were narrow. Wider limits of agreement with a systematic bias of 7.7 mmHg were noted with pCO2 . The utility of VBG pH and HCO3 was again demonstrated. VBG pCO2 in this cohort of patients may have a role in the assessment of patients with AECOPD. Further study is needed on the possible role of VBG in the management of such patients with T2RF particularly those using non-invasive ventilation.

Prise en charge non invasive de l’insuffisance respiratoire aiguë de l’obèse morbide

Acute respiratory failure is common but nevertheless a challenging situation in morbidly obese patients. Extreme obesity can lead to numerous respiratory disorders including reduced functional residual capacity and limited expiratory flow especially in the supine position, increased work of breathing, abnormal upper airway collapsibility, gravitational atelectasis, and blunted central ventilatory response to hypercapnia and hypoxaemia. Good understanding of the physiological mechanisms involved in obesity-associated respiratory failure is mandatory to early identify and to improve management of morbidly obese patients with acute respiratory failure. Sitting position and noninvasive ventilation (NIV) are the two cornerstones of the initial therapeutic management of those patients. In the setting of type-2 respiratory failure, early noninvasive management is almost constantly successful and prevents escalation to intubation. Conversely, type-1 respiratory failure is the leading cause of NIV failure and death especially when caused by a pneumonia. In that case, given the multiple organ disorders associated with extreme obesity, invasive procedures and aggressive management in the intensive care unit are usually doomed to failure in the frail morbidly obese patients.

M29 National Early Warning Score (NEWS): Is it bad news for our patients?

Background Titrated oxygen has been shown to significantly reduce mortality in patients presenting with acute exacerbations of chronic obstructive pulmonary disease (COPD) 1 . All patients at risk of type 2 respiratory failure (T2RF) should be administered oxygen in accordance with British Thoracic Society Guidelines. However, the NEWS system proposed by the Royal College of Physicians makes no allowance for patients at risk of T2RF and may lead to potential over oxygenation in this group of patients 2 . Objective To assess the use of the NEWS in patients with T2RF in our district general hospital and to assess the safety of a modified system. Methods Patients were selected from the Medical Admissions Unit. Inclusion criteria were oxygen prescription or oxygen in situ . Data were collected over 5 consecutive days. Conventional NEWS for these patients were compared with a system currently being piloted at Salford Royal Foundation Trust with modified oxygen saturation levels (SpO2) for patients at risk of T2RF (Table 1) Results 69 patients were assessed. 32% (22/69) had risk factors for T2RF. 21 had COPD and one had sleep apnoea. 55% (12/22) had oxygen saturations in their target range or were above target saturations but on air. 32% (7/22) were on oxygen and had saturations above 92%. 14% (3/22) had saturations below 88%. 73% (16/22) of at risk patients had their scores altered when using the Salford EWS system. 69% (11/16) of these patients had their scores reduced. 4 patient’s scores were reduced by 3, 4 were reduced by 2 and 3 were reduced by 1. 31% (5/16) of patient’s scores were increased. 4 scores were increased by 2 and 1 increased by 1. The score differences were due to over oxygenation. Conclusions The current NEWS system appears to increase the risk of over oxygenation in patients at risk of T2RF. Using a modified score for patients at risk of T2RF will reduces this risk. With thanks Ronan O’Driscoll, Salford Foundation Trust for use of the modified Salford NEWS chart

A reply

We thank Drs Patil and Maloney for their comment that supplementary oxygen may be beneficial for up to ten minutes after nitrous oxide anaesthesia and we would hope that continuous monitoring of oxygen saturation postoperatively will ensure that the oxygen dose is titrated to the patient's needs in these particular circumstances. Dr Gwinnutt suggests that our article 1 over-emphasised the risks of hyperoxaemia and type-2 respiratory failure but under-estimated the risks of hypoxaemia amongst patients cared for by anaesthetic colleagues. We agree that the best known example of oxygen sensitivity is the patient with acute exacerbation of chronic obstructive pulmonary disease (COPD), a condition much less common in anaesthetic and surgical practice than on medical wards. However, anaesthetists need to be aware that approximately 9% of UK adults aged > 65 have evidence of severe or very severe COPD on routine spirometry and about 2% of UK adults have morbid obesity, another condition where supplementary oxygen may cause hypercapnic respiratory failure 2-4. Patients with severe skeletal deformity or neuromuscular conditions causing hypercapnic respiratory failure may also present for surgery. In addition to these at-risk groups, even healthy adults can develop hypercapnic respiratory failure due to hypoventilation if given opioids. Audits at our institution found that 13% of blood gas specimens from surgical wards were hypercapnic (PCO2 > 6.0 kPa) compared with 29% of specimens from patients on medical wards, confirming that type-2 respiratory failure is less common (but not rare) on surgical wards. Type-2 respiratory failure was twice as common as type-1 (PO2 < 8.0 kPa with normal or low PCO2) on a hospital-wide basis 5, 6. We have analysed this audit database further and the results are shown in Table 1: type-2 respiratory failure is actually more common than pure hypoxaemia (type-1 respiratory failure) in blood gas samples from surgical wards, surgical HDU, theatres and ICU. Type-2 respiratory failure complicated by respiratory acidosis was commoner than type-1 failure on surgical HDU and in theatre and ICU and many additional patients had a mixed metabolic and respiratory acidosis. Our data also demonstrated that many patients in surgical and anaesthetic areas were hyperoxaemic including a high proportion with type-2 respiratory failiure. A random sample of casenotes identified risk factors for type-2 respiratory failure in 18% of the patients who required blood gas analysis on surgical wards and 23% from theatre samples. Education of medical students and junior doctors will need to reflect that type-2 respiratory failure is commoner than type-1, and that many patients with type-2 respiratory failure are hyperoxaemic due to oxygen therapy. Gwinnutt has not presented any evidence of benefit from the routine use of supplementary oxygen in postoperative care as distinct from our proposal to monitor patients carefully and give this drug to those who need it. The lack of likely benefit of routine supplemental postoperative oxygen, together with the potential hazards, were reviewed in detail by Downs and Rothen, who are both trained in anaesthesia 7, 8. We agree strongly with Gwinnutt that pulse oximetry and the administration of supplemental oxygen is only a small part of the assessment and resuscitation of at-risk patients, as discussed in the second paragraph of our editorial. We would guide readers to section 7 of the British Thoracic Society Emergency Oxygen Guideline which is devoted to the detailed clinical and laboratory assessment of seriously ill patients, and to Box 4 in our recent review of emergency oxygen use where we discuss several ways to increase tissue oxygen delivery, including the importance of airway management and blood transfusion when appropriate 9, 10.

Noninvasive Positive Pressure Ventilation Improved Refractory Behavioral and Psychological Symptoms of Dementia in an Elderly Adult with Type 2 Respiratory Failure

Noninvasive Positive Pressure Ventilation Improved Refractory Behavioral and Psychological Symptoms of Dementia in an Elderly Adult with Type 2 Respiratory Failure

Hazards of tube thoracostomy in patients on a ventilator

A patient with post-pneumonia empyema complicated by type-2 respiratory failure required mechanical ventilation as part of his therapy. A pneumothorax was noted on his chest radiograph. This was treated with an intercostal chest drain (ICD). Unfortunately, he was still hypoxic, his subcutaneous emphysema was worsening and the ICD was bubbling. A computed tomography (CT) scan of chest demonstrated that the ICD has penetrated the right upper lobe parenchyma. A new ICD was inserted and the previous one was removed. Although both hypoxia and subcutaneous emphysema improved, the patient chronically remained on mechanical ventilation.