Non-invasive ventilation

Clinical review of high-flow nasal oxygen therapy in human and veterinary patients

Oxygen therapy is the first-line treatment for hypoxemic acute respiratory failure. In veterinary medicine this has traditionally been provided via mask, low-flow nasal oxygen cannulas, oxygen cages and invasive positive pressure ventilation. Traditional non-invasive modalities are limited by the maximum flow rate and fraction of inspired oxygen (FiO₂) that can be delivered, variability in oxygen delivery and patient compliance. The invasive techniques are able to provide higher FiO₂ in a more predictable manner but are limited by sedation/anesthesia requirements, potential complications and cost. High-flow nasal oxygen therapy (HFNOT) represents an alternative to conventional oxygen therapy. This modality delivers heated and humidified medical gas at adjustable flow rates, up to 60 L/min, and FiO₂, up to 100%, via nasal cannulas. It has been proposed that HFNOT improves pulmonary mechanics and reduces respiratory fatigue via reduction of anatomical dead space, provision of low-level positive end-expiratory pressure (PEEP), provision of constant FiO₂ at rates corresponding to patient requirements and through improved patient tolerance. Investigations into the use of HFNOT in veterinary patients have increased in frequency since its clinical use was first reported in dogs with acute respiratory failure in 2016. Current indications in dogs include acute respiratory failure associated with pulmonary parenchymal disease, upper airway obstruction and carbon monoxide intoxication. The use of HFNOT has also been advocated in certain conditions in cats and foals. HFNOT is also being used with increasing frequency in the treatment of a widening range of conditions in humans. Although there remains conflict regarding its use and efficacy in some patient groups, overall these reports indicate that HFNOT decreases breathing frequency and work of breathing and reduces the need for escalation of respiratory support. In addition, they provide insight into potential future veterinary applications. Complications of HFNOT have been rarely reported in humans and animals. These are usually self-limiting and typically result in lower morbidity and mortality than those associated with invasive ventilation techniques.

Effect of bilevel continuous positive airway pressure for patients with type II respiratory failure due to acute exacerbation of COPD: A protocol for systematic review and meta-analysis

BACKGROUND

The purpose of this study is to determine the therapeutic efficacy of bi-level continuous positive airway pressure (BIPAP) intervention in patients with type II respiratory failure due to acute exacerbation of chronic obstructive pulmonary disease (COPD).

METHODS

This review will only include randomized controlled trials (RCTs). The search strategy will be applied to 4 Chinese databases: China National Knowledge Infrastructure (CNKI), Wanfang Database, Chinese Science and Technology Journal Database (VIP), and Chinese Biomedical Literature Database (SinoMed); and 5 foreign literature databases: PubMed, Cochrane Library, Springer, EBSCO, and Web of Science. RCTs published from inception to October 2020 will be included. The 2 researchers will independently screen and extract the data and assess quality. The main results obtained through blood gas analysis and equipment observation, heterogeneity assessment, sensitivity analysis, funnel chart synthesis, data synthesis, and grouping analysis will be carried out using Review Manager 5.4 software. The trial sequential analysis will be completed using TSA v0.9 developed by the CTU at the Copenhagen Clinical Trial Center.

RESULTS

In the current meta-analysis, we will provide more practical and targeted results for the therapeutic efficacy of BIPAP in patients with type II respiratory failure due to acute exacerbation of COPD.

CONCLUSION

This study will provide new evidence for the therapeutic efficacy of BIPAP in patients with type II respiratory failure due to acute exacerbation of COPD.

REGISTRATION NUMBER

INPLASY2020110003 (DOI:10.37766/inplasy2020.11.0003).

Recovery from hypoxemia and Hypercapnia following noninvasive pressure support ventilation in a patient with statin-associated necrotizing myopathy: a case report

Background

Statin-associated necrotizing myopathy (SANM) is a rare autoimmune disorder caused by administration of statins. SANM is characterized by weakness due to necrosis and regeneration of myofibers. Here we report the first case of SANM with acute respiratory failure treated with noninvasive pressure support ventilation in addition to immunosuppressants.

Case presentation

A 59-year-old woman who had been treated with 2.5 mg/day of rosuvastatin calcium for 5 years stopped taking the drug 4 months before admission to our hospital due to elevation of creatine kinase (CK). Withdrawal of rosuvastatin for 1 month did not decrease the level of CK, and she was admitted to our hospital due to the development of muscle weakness of her neck and bilateral upper extremities. Anti-3-hydroxy-3-methylglutaryl coenzyme A reductase antibodies were positive. Magnetic resonance imaging showed myositis, and muscle biopsy from the right biceps brachii muscle showed muscle fiber necrosis and regeneration without inflammatory cell infiltration, suggesting SANM. After the diagnosis, she received methylprednisolone pulse therapy (mPSL, 1 g/day × 3 days, twice) and subsequent oral prednisolone therapy (PSL, 30 mg/day for 1 month, 25 mg/day for 1 month and 22.5 mg/day for 1 month), leading to improvement of her muscle weakness. One month after the PSL tapering to 20 mg/day, her muscle weakness deteriorated with oxygen desaturation (SpO2: 93% at room air) due to hypoventilation caused by weakness of respiratory muscles. BIPAP was used for the management of acute respiratory failure in combination with IVIG (20 g/day × 5 days) followed by mPSL pulse therapy (1 g/day × 3 days), oral PSL (30 mg/day × 3 weeks, then tapered to 25 mg/day) and tacrolimus (3 mg/day). Twenty-seven days after the start of BIPAP, she was weaned from BIPAP with improvement of muscle weakness, hypoxemia and hypercapnia. After she achieved remission with improvement of muscle weakness and reduction of serum CK level to a normal level, the dose of oral prednisolone was gradually tapered to 12.5 mg/day without relapse for 3 months.

Conclusions

Our report provides new insights into the role of immunosuppressants and biphasic positive airway pressure for induction of remission in patients with SANM.

Respiratory physiotherapy in intensive care unit: Bibliographic review

INTRODUCTION AND AIMS

Patients in intensive care unit are susceptible to complications due to different causes (underlying disease, immobilisation, infection risk…) The current main intervention in order to prevent these complications is respiratory physiotherapy, a common practice for nurses on a daily basis. Therefore, we decided to carry out this bibliographic review to describe the most efficient respiratory physiotherapy methods for the prevention and treatment of lung complications in patients in intensive care, taking into account the differences between intubated and non-intubated patients.

METHODOLOGY

The bibliographic narrative review was carried out on literature available in Pubmed, Cinahl and Cochrane Library. The established limits were language, evidence over the last 15 years and age.

RESULTS

Techniques involving lung expansion, cough, vibration, percussion, postural drainage, incentive inspirometry and oscillatory and non-oscillatory systems are controversial regarding their efficacy as respiratory physiotherapy methods. However, non-invasive mechanical ventilation shows clear benefits. In the case of intubated patients, manual hyperinflation and secretion aspirations are highly efficient methods for the prevention of the potential complications mentioned above. In this case, other RP methods showed no clear efficiency when used individually.

DISCUSSION AND CONCLUSIONS

Non-invasive mechanical ventilation (for non-intubated patients) and manual hyperinflation (for intubated patients) proved to be the respiratory physiotherapy methods with the best results. The other techniques are more controversial and the results are not so clear. In both types of patients this literature review suggests that combined therapy is the most efficient.

Effect of portable non-invasive ventilation & environmental conditions on everyday activities

The current study examined the effect of non-invasive ventilation (NIV) within environments of differing temperature and humidity on several physiological and perceptual responses while performing six activities of daily living (i.e. putting on shirt/shoes/trousers, vacuuming, hanging towels, and walking on a treadmill). Sixteen healthy participants completed the activities of varying difficulty within four experimental conditions: with and without NIV; and in temperate (22°C, 40% relative humidity) and hot-humid environments (32°C, 70% relative humidity). Comparisons of physiological responses between conditions were examined via repeated measures ANOVAs. Overall, NIV resulted in similar physiological and perceptual responses within all environmental conditions for healthy participants. Further, NIV use increased heart rate during the most strenuous task (29.5±12.7 vs. 22.8±12.0bpm, p=0.008) indicating NIV use may stress cardiovascular functioning during moderate-high intensity activities. Tropical conditions did not alter physiological or perceptual responses during everyday tasks with NIV use by healthy adults. Future investigations examining the independent and combined impacts of task intensity, extreme environments and NIV use will clarify the benefits of NIV for healthy and clinical populations.

Factors influencing compliance with non-invasive ventilation at long-term in patients with myotonic dystrophy type 1: A prospective cohort

This study evaluated compliance with non-invasive ventilation in patients with myotonic dystrophy type 1 and identified predictors of cessation at 5 years in a cohort of patients followed in a specialist center for Neuromuscular Diseases in France. Mechanical ventilation in these patients poses a very strong challenge to caregivers. Factors predicting relative compliance were identified using multivariate linear regressions. Cox proportional-hazards regression was used to estimate hazard ratios associated with risk of cessation. One hundred and twenty-eight patients were included. Compliance during the first year was higher when symptoms of respiratory failure were initially present (+25%, p < 0.003) and lower in the case of acute respiratory failure (-29%, p < 0.003). Long-term compliance was associated with symptoms of respiratory failure (+52%, p < 0.0001) and nocturnal arterial oxygen desaturation (+23%, p < 0.007). Cessation was more frequent in the cases of excessive leaks (HR = 7.81, IC [1.47-41.88], p < 0.01), ventilator dysfunction requiring emergency technical intervention (HR = 12.58, IC [1.22-129.69], p < 0.03) or high body mass index (p < 0.02). Cessation was less frequent for patients with a professional occupation or undergoing professional training (HR = 0.11, IC [0.02-0.77], p < 0.02). Compliance with non-invasive ventilation is poor in patients with no subjective symptoms of respiratory failure. It may be improved with appropriate education and follow-up.

Effects of noninvasive positive pressure ventilation on oxygenation status and prognosis in patients with acute paraquat-induced lung injury

PURPOSE

The aim of this study was to evaluate the effects of noninvasive positive pressure ventilation (NIPPV) on oxygenation status and prognosis in patients with acute lung injury induced by paraquat (PQ) poisoning.

METHODS

Patients with acute PQ-induced lung injury treated with NIPPV were admitted to an emergency intensive care unit. Changes in oxygenation status (respiratory rate and the partial pressure of alveolar O2 and CO2 [PaO2 and PaCO2, respectively]) after initial NIPPV were observed. Differences in inspiratory pressure (PI) between nonsurvivors and survivors were compared. The relationship between PI and the prognosis of patients with acute PQ-induced lung injury was evaluated.

FINDINGS

A total of 86 patients (47 women, 39 men; mean age, 33.5 [24.5] years [range, 22-61 years]) were included. There were significant differences in respiratory rate, PaO2, and PaCO2 from before to after initial NIPPV (respiratory rate, 35 [14] vs 26 [16] min(-1) [P = 0.037]; PaO2, 61.8 [19.6] vs 73.5 [26.8] mm Hg [P = 0.046]; and PaCO2, 27.7 [16.4] vs 34.6 [19.2] mm Hg [P = 0.039]). The overall mortality rate was 75.6% (65/86) during a 28-day follow-up period. We observed a significant difference in initial PI (PIinit) between nonsurvivors and survivors (8.2 [4.3] vs 6.6 [3.8] cm H2O; P = 0.043). Furthermore, nonsurvivors had a greater maximal PI (PImax) than did survivors (21.6 [9.8] vs 15.4 [8.5] cm H2O; P = 0.022). Correlation analysis revealed that both PIinit and PImax were associated with a poor prognosis in patients with acute PQ-induced lung injury (PIinit, r = -0.29 [P = 0.038]; PImax, r = -0.31 [P = 0.042]).

IMPLICATIONS

NIPPV may effectively improve oxygenation status in patients with acute PQ-induced lung injury, thereby relieving dyspnea and promoting the recovery of pulmonary function. PIinit and PImax may be important determinants of prognosis in acute PQ-induced lung injury. These findings need further verification in a large-scale, multicenter, randomized controlled study that combines other factors with a relatively long-term follow-up.

Noninvasive ventilation in acute cardiogenic pulmonary edema

PURPOSE OF REVIEW

Patients with acute pulmonary edema are often treated with noninvasive ventilation (NIV). There are essentially two modalities used in this setting: continuous positive airway pressure and bilevel pressure support ventilation. The clinical impact of these techniques and the subset of patients who can benefit from their application have not been definitely established.

RECENT FINDINGS

The main advantage of the use of NIV in patients with severe acute pulmonary edema is to avoid intubation by more effectively decreasing respiratory distress with respect to conventional oxygen therapy. These beneficial effects were demonstrated in three meta-analyses including nearly 900 patients. Although neither technique was superior to the other in the comparative analysis, a tendency to reduce hospital mortality was observed, which was statistically significant for continuous positive airway pressure. However, unpublished data from a large multicenter trial comparing both modalities of NIV to conventional treatment in emergency departments did not confirm these results. Recent research has pointed out a clear advantage when the treatment is initiated early in the prehospital setting.

SUMMARY

Although in acute pulmonary edema NIV is more effective in improving respiratory distress than conventional oxygen therapy and reduces the necessity of intubation, the subset of patients who can best benefit from these techniques in terms of mortality still warrant further investigation.