Clinical review: Noninvasive ventilation in the clinical setting--experience from the past 10 years

Effects of ventilator settings, nebulizer and exhalation port position on albuterol delivery during non-invasive ventilation: an in-vitro study

Background

Few studies have investigated the factors affecting aerosol delivery during non-invasive ventilation (NIV). Our aim was to investigate, using a bench-top model, the effect of different ventilator settings and positions of the exhalation port and nebulizer on the amount of albuterol delivered to a lung simulator.

Methods

A lung model simulating spontaneous breathing was connected to a single-limb NIV ventilator, set in bi-level positive airway pressure (BIPAP) with inspiratory/expiratory pressures of 10/5, 15/10, 15/5, and 20/10 cmH₂O, or continuous positive airway pressure (CPAP) of 5 and 10 cmH₂O. Three delivery circuits were tested: a vented mask with the nebulizer directly connected to the mask, and an unvented mask with a leak port placed before and after the nebulizer. Albuterol was collected on a filter placed after the mask and then the delivered amount was measured with infrared spectrophotometry.

Results

Albuterol delivery during NIV varied between 6.7 ± 0.4% to 37.0 ± 4.3% of the nominal dose. The amount delivered in CPAP and BIPAP modes was similar (22.1 ± 10.1 vs. 24.0 ± 10.0%, p = 0.070). CPAP level did not affect delivery (p = 0.056); in BIPAP with 15/5 cmH₂O pressure the delivery was higher compared to 10/5 cmH₂O (p = 0.033) and 20/10 cmH₂O (p = 0.014). Leak port position had a major effect on delivery in both CPAP and BIPAP, the best performances were obtained with the unvented mask, and the nebulizer placed between the leak port and the mask (p < 0.001).

Conclusions

In this model, albuterol delivery was marginally affected by ventilatory settings in NIV, while position of the leak port had a major effect. Nebulizers should be placed between an unvented mask and the leak port in order to maximize aerosol delivery.

Noninvasive Ventilation in Patients With Hematologic Malignancy

INTRODUCTION

Noninvasive ventilation (NIV) is commonly used as first-line therapy for immunocompromised patients with acute respiratory failure. However, it may not be appropriate for all patients, as failure of NIV and delayed endotracheal intubation (ETI) may increase mortality. We report our center's experience and outcomes for patients with active hematologic malignancy (HM) treated with NIV.

METHODS

We conducted a retrospective study of consecutive patients with HM who were admitted to the intensive care unit (ICU) of Mount Sinai Hospital for acute respiratory failure between January 1, 2010, and May 31, 2015, and were initially treated with NIV. We compared the characteristics of patients who were successfully treated with NIV and avoided intubation and those who failed NIV.

RESULTS

Seventy-nine patients (mean age 56 ± 14 years, mean Acute Physiology and Chronic Health Evaluation II score 27 ± 5) with HM were treated with NIV for acute respiratory failure. The etiology of respiratory failure was multifactorial in 31 (39%) patients, with features of pneumonia in 61 (77%) patients, severe sepsis or septic shock in 33 (42%) patients, and pulmonary edema in 24 (30%) patients. The majority of patients were admitted with acute leukemia (n = 60, 76%), 8 (10%) with lymphoma, and 11 (14%) with chronic leukemia, multiple myeloma, or myelodysplastic syndrome. Of the 79 patients treated with NIV, 44 (56%) failed NIV and required ETI, 7 (9%) had a do-not-intubate (DNI) order and died, and 28 (35%) avoided ETI. Compared with patients who avoided ETI, those who failed NIV or had a DNI order and died were more likely to have acute leukemia (84% vs 61%; P = .02) and at baseline had higher Paco2 (39 vs 30; P = .038), higher fraction of inspired oxygen (Fio2) requirements (0.6 vs 0.4; P = .002), and more vasopressor use (31% vs 11%; P = .059). The ICU mortality was 42%; 3-month mortality was 57% overall and was significantly lower in the NIV success patients compared with the NIV failure group (21% vs 74%; P < .001).

CONCLUSION

Two-thirds of patients with HM and respiratory failure failed NIV and required ETI, and had high subsequent mortality. Patients who failed NIV had higher Paco2, higher Fio2, and a trend toward more vasopressor use.

Early warning and prevention of pneumonia in acute leukemia by patient education, spirometry, and positive expiratory pressure: A randomized controlled trial

Long‐lasting neutropenia associated with acute myeloid leukemia (AML) and its treatment gives rise to a high risk of pneumonia. The use of broad‐spectrum antibiotic prophylaxis during outpatient management has not completely protected patients against admission due to infections and neutropenic fever, emphasizing the need to approach infection protection with complementary efforts. In a randomized controlled design, we examined the applicability of patient‐performed daily spirometry [forced expiratory volume in one second (FEV1)] as an early warning tool and explored the effectiveness of positive expiratory pressure (PEP) in preventing pneumonia among 80 AML patients. Twenty‐five incidences of pneumonia were detected among 23 patients (6 interventions, 17 controls), giving a prevalence of 28.75% during 5420 days of observation. We found a significant difference in incidence between intervention versus control group (2.17 per 1000 days vs. 6.52 per 1000 days, P = 0.021, respectively). A cross point at 80‐76% of the personal FEV1 reference value showed high sensitivity and specificity on pneumonia development. Our data demonstrate the feasibility of educating AML patients in their continuous daily measurement of FEV1 and use of PEP. Daily measures of FEV1 may be an important early warning tool for assessment of pulmonary deterioration during critical phases of neutropenia. We suggest that strategic patient education in the use of spirometry and PEP should be part of standard of care for AML patients undergoing induction chemotherapy. Am. J. Hematol. 91:271–276, 2016. © 2015 The Authors. American Journal of Hematology Published by Wiley Periodicals, Inc.

Brazilian recommendations of mechanical ventilation 2013. Part I

Perspectives on invasive and noninvasive ventilatory support for critically ill patients are evolving, as much evidence indicates that ventilation may have positive effects on patient survival and the quality of the care provided in intensive care units in Brazil. For those reasons, the Brazilian Association of Intensive Care Medicine (Associação de Medicina Intensiva Brasileira - AMIB) and the Brazilian Thoracic Society (Sociedade Brasileira de Pneumonia e Tisiologia - SBPT), represented by the Mechanical Ventilation Committee and the Commission of Intensive Therapy, respectively, decided to review the literature and draft recommendations for mechanical ventilation with the goal of creating a document for bedside guidance as to the best practices on mechanical ventilation available to their members. The document was based on the available evidence regarding 29 subtopics selected as the most relevant for the subject of interest. The project was developed in several stages, during which the selected topics were distributed among experts recommended by both societies with recent publications on the subject of interest and/or significant teaching and research activity in the field of mechanical ventilation in Brazil. The experts were divided into pairs that were charged with performing a thorough review of the international literature on each topic. All the experts met at the Forum on Mechanical Ventilation, which was held at the headquarters of AMIB in São Paulo on August 3 and 4, 2013, to collaboratively draft the final text corresponding to each sub-topic, which was presented to, appraised, discussed and approved in a plenary session that included all 58 participants and aimed to create the final document.

Brazilian recommendations of mechanical ventilation 2013. Part I

Perspectives on invasive and noninvasive ventilatory support for critically ill patients are evolving, as much evidence indicates that ventilation may have positive effects on patient survival and the quality of the care provided in intensive care units in Brazil. For those reasons, the Brazilian Association of Intensive Care Medicine (Associação de Medicina Intensiva Brasileira - AMIB) and the Brazilian Thoracic Society (Sociedade Brasileira de Pneumologia e Tisiologia - SBPT), represented by the Mechanical Ventilation Committee and the Commission of Intensive Therapy, respectively, decided to review the literature and draft recommendations for mechanical ventilation with the goal of creating a document for bedside guidance as to the best practices on mechanical ventilation available to their members. The document was based on the available evidence regarding 29 subtopics selected as the most relevant for the subject of interest. The project was developed in several stages, during which the selected topics were distributed among experts recommended by both societies with recent publications on the subject of interest and/or significant teaching and research activity in the field of mechanical ventilation in Brazil. The experts were divided into pairs that were charged with performing a thorough review of the international literature on each topic. All the experts met at the Forum on Mechanical Ventilation, which was held at the headquarters of AMIB in São Paulo on August 3 and 4, 2013, to collaboratively draft the final text corresponding to each sub-topic, which was presented to, appraised, discussed and approved in a plenary session that included all 58 participants and aimed to create the final document.

Adaptation to different noninvasive ventilation masks in critically ill patients

OBJECTIVE:

To identify which noninvasive ventilation (NIV) masks are most commonly used and the problems related to the adaptation to such masks in critically ill patients admitted to a hospital in the city of São Paulo, Brazil.

METHODS:

An observational study involving patients ≥ 18 years of age admitted to intensive care units and submitted to NIV. The reason for NIV use, type of mask, NIV regimen, adaptation to the mask, and reasons for non-adaptation to the mask were investigated.

RESULTS:

We evaluated 245 patients, with a median age of 82 years. Acute respiratory failure was the most common reason for NIV use (in 71.3%). Total face masks were the most commonly used (in 74.7%), followed by full face masks and near-total face masks (in 24.5% and 0.8%, respectively). Intermittent NIV was used in 82.4% of the patients. Adequate adaptation to the mask was found in 76% of the patients. Masks had to be replaced by another type of mask in 24% of the patients. Adequate adaptation to total face masks and full face masks was found in 75.5% and 80.0% of the patients, respectively. Non-adaptation occurred in the 2 patients using near-total facial masks. The most common reason for non-adaptation was the shape of the face, in 30.5% of the patients.

CONCLUSIONS:

In our sample, acute respiratory failure was the most common reason for NIV use, and total face masks were the most commonly used. The most common reason for non-adaptation to the mask was the shape of the face, which was resolved by changing the type of mask employed.

Performance of different continuous positive airway pressure helmets equipped with safety valves during failure of fresh gas supply

PURPOSE

We assessed the performance of different continuous positive airway pressure (CPAP) helmets equipped with a safety valve during discontinuation of fresh gas flow.

METHODS

This was a physiological study of five healthy volunteers. We delivered CPAP (fresh gas flow 60 l/min, FiO(2) 60%, PEEP 5 cmH(2)O) with three different helmets in a random sequence: 4Vent (Rüsch), HelmHAR-cp (Harol) and CaStar CP210 (StarMed). For each helmet we randomly applied, for up to 4 min, three disconnections of fresh gas flow: helmet inlet (D(inlet)), flowmeter (D(flowmeter)) and gas source (D(source)). We continuously recorded from a nostril: end-tidal CO(2) (PetCO(2)), inspiratory CO(2) (PiCO(2)), fraction of inspired oxygen (FiO(2)) and respiratory rate (RR).

RESULTS

During every disconnection we observed an increase in PiCO(2) and PetCO(2) with a drop in FiO(2), while RR did not change. FiO(2) decreased more quickly in the CaStar, equipped with the largest safety valve, during D(source) and D(flowmeter), while FiO(2) decreased more quickly during D(inlet) in CaStar and in 4Vent. PiCO(2) resulted in a lower increase in CaStar during D(source) and D(flowmeter) compared to 4Vent. PetCO(2) in CaStar increases more slowly compared to 4Vent during D(source) and more slowly compared to the other two helmets during D(flowmeter). During D(inlet) similar degrees of CO(2) rebreathing and PetCO(2) were recorded among all the helmets.

CONCLUSIONS

To minimize CO(2) rebreathing during disconnection of the fresh gas supply while performing helmet CPAP, it is desirable to utilize large helmets with a large anti-suffocation valve. Monitoring and alarm systems should be employed for safe application of helmet CPAP.

Predicting the success of noninvasive positive pressure ventilation in emergency room for patients with acute heart failure

BACKGROUND

Non-invasive positive pressure ventilation (NPPV) for acute heart failure (AHF) is increasingly used to avoid endotracheal intubation (ETI). We therefore reviewed our experience using respirator management in the emergency room for AHF, and evaluated the predictive factors in the success of NPPV in the emergency room.

METHODS AND RESULTS

Three-hundred forty-three patients with AHF were analyzed. The AHF patients were assigned to either BiPAP-Synchrony (B-S; Respironics, Merrysville, PA, USA) period (2005-2007, n = 176) or BiPAP-Vision (B-V; Respironics) period (2008-2010, n = 167). The rate of carperitide use was significantly increased and dopamine use was significantly decreased in the B-V period. The total length of hospital stay was significantly shorter in the B-V period. AHF patients were also assigned to a failed trial of NPPV followed by ETI (NPPV failure group) or an NPPV success group in the emergency room for each period. NPPV was successfully used in 48 cases in the B-S period, and in 111 cases in the B-V period. Fifty-seven ETI patients included 45 direct ETI and 11 NPPV failure cases in the B-S period, and 16 ETI patients included 10 direct ETI and 6 NPPV failure cases in the B-V period. The pH values were significantly lower in the NPPV failure than in the NPPV success for both periods (7.19 ± 0.10 vs. 7.28 ± 0.11, B-S period, p < 0.05; 7.05 ± 0.08 vs. 7.27 ± 0.14, B-V period, p < 0.001). A pH value of 7.20 produced the optimal balance in the B-S period, while that of 7.03 produced the optimal balance in B-V periods by the ROC curve analysis. The cutoff value of pH was lower in the B-V period than in the B-S period.

CONCLUSIONS

This predictive value provides successful estimates of NPPV with a high sensitivity and specificity, and the aortic blood gas level was above 7.03 pH when using the B-V system.

Weaning failure of cardiac origin: recent advances

This article is one of ten reviews selected from the Yearbook of Intensive Care and Emergency Medicine 2010 (Springer Verlag) and co-published as a series in Critical Care. Other articles in the series can be found online at http://ccforum.com/series/yearbook. Further information about the Yearbook of Intensive Care and Emergency Medicine is available from http://www.springer.com/series/2855.

[Non-invasive ventilation]

Non-invasive ventilation (NIV) is a technique that delivers mechanical ventilation avoiding side effects and complications associated with endotracheal intubation and invasive mechanical ventilation. This technique has proved to be effective in different types of respiratory failure. In this article, the authors revise the advantages and limitations of NIV, interfaces used and indications in acute and acute-on-chronic respiratory failure.

[Advanced life support under special circumstances: part 1]

Based on the 2005 International Consensus Conference on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations of the International Liaison Committee on Resuscitation (ILCOR), guidelines were published for managing basic and advanced life-saving procedures in the event of cardiac arrest. The fact that special circumstances sometimes must be considered in patient treatment resulted in a separate chapter. This first part of a two-part article reviews essential information as well as necessary modifications of the standard advanced life support algorithm in cases of life-threatening drowning, asthma, anaphylaxis, and poisoning. The second part will deal with electrolyte disorders, hypothermia, electrical emergencies, trauma, cardiac arrest during pregnancy, and cardiac surgery.

Closed-loop ventilation: an emerging standard of care?

The rational for using closed loop ventilation is becoming strong and stronger. Studies are now available supporting the hypothesis that patient outcome is improved by using closed loop ventilation. In the highly sophisticated ICU world driven by the triumvirate of cost-efficiency, quality, and safety, closed loop ventilation will become definitely unavoidable. The challenge is how to make that change effortless, "friendly" and as fast as possible. Introducing novel graphical user interfaces and providing data displays that are pertinent, integrative and dynamic will reduce cognitive resources of the clinician and have the potential to make ventilation safer. They may be the key to adopt closed loop ventilation in everyday practice.

Efficacy and safety of non-invasive ventilation in the treatment of acute cardiogenic pulmonary edema--a systematic review and meta-analysis

INTRODUCTION

Continuous positive airway pressure ventilation (CPAP) and non-invasive positive pressure ventilation (NPPV) are accepted treatments in acute cardiogenic pulmonary edema (ACPE). However, it remains unclear whether NPPV is better than CPAP in reducing the need for endotracheal intubation (NETI) rates, mortality and other adverse events. Our aim was to review the evidence about the efficacy and safety of these two methods in ACPE management.

METHODS

We conducted a systematic review and meta-analysis of randomized controlled trials on the effect of CPAP and/or NIPV in the treatment of ACPE, considering the outcomes NETI, mortality and incidence of acute myocardial infarction (AMI). We searched six electronic databases up to May 2005 without language restrictions, reviewed references of relevant articles, hand searched conference proceedings and contacted experts.

RESULTS

Of 790 articles identified, 17 were included. In a pooled analysis, 10 studies of CPAP compared to standard medical therapy (SMT) showed a significant 22% absolute risk reduction (ARR) in NETI (95% confidence interval (CI), -34% to -10%) and 13% in mortality (95%CI, -22% to -5%). Six studies of NPPV compared to SMT showed an 18% ARR in NETI (95%CI, -32% to -4%) and 7% in mortality (95%CI, -14% to 0%). Seven studies of NPPV compared to CPAP showed a non-significant 3% ARR in NETI (95%CI, -4% to 9%) and 2% in mortality (95%CI, -6% to 10%). None of these methods increased AMI risk. In a subgroup analysis, NPPV did not lead to better outcomes than CPAP in studies including more hypercapnic patients.

CONCLUSION

Robust evidence now supports the use of CPAP and NPPV in ACPE. Both techniques decrease NETI and mortality compared to SMT and none shows increased AMI risk. CPAP should be considered a first line intervention as NPPV did not show a better efficacy, even in patients with more severe conditions, and CPAP is cheaper and easier to implement in clinical practice.