Brazilian recommendations of mechanical ventilation 2013. Part 2

Inspiratory Muscle Training Strategies in Tracheostomized Critically Ill Individuals

BACKGROUND

Inspiratory muscle training (IMT) strategies can reduce ICU length of stay and optimize recovery in critically ill patients. Our objective was to compare IMT combined with spontaneous breathing with T-piece in tracheostomized subjects.

METHODS

Tracheostomized critically ill subjects who were ready to wean were selected and randomly allocated to one of 2 groups: electronically-assisted IMT (EIMT) or spontaneous breathing with T-piece. Electronically assisted IMT was delivered using 30% of maximal inspiratory pressure (manual EIMT or automatically adjusted loads). The following variables were analyzed: ICU length of stay, weaning time, maximal inspiratory pressure, rapid shallow breathing index, pressure (cm H₂O), power (W), flow (L/s), volume (L), and energy (J).

RESULTS

A total of 132 patients were assessed; 104 subjects were enrolled with EIMT, n = 51 (automatic EIMT, n = 25 and manual EIMT n = 26), or spontaneous breathing with T-piece group, n = 53. The Acute Physiology and Chronic Health Evaluation II score was significantly higher (P = .02) in subjects in the manual EIMT group. Weaning time did not differ significantly between groups (8.55 ± 6.48 d and 10.86 ± 6.48 d, EIMT and spontaneous breathing with T-piece group, respectively; P = .23). Weaning success rates (75%) were lower in the manual EIMT group. Invasive mechanical ventilation time was longer but not significantly different (P = .21) in the spontaneous breathing with T-piece group. Maximal inspiratory pressure was significantly higher in the spontaneous breathing with T-piece and the automatic EIMT groups (P < .001 and P = .007, respectively). Pressure, power, and energy values were significantly higher in the manual EIMT group (P < .001, P = .003, and P = .003, respectively).

CONCLUSIONS

IMT modalities in this trial had no significant impacts on weaning time or successful weaning rates.

Association of Functional Characteristics and Physiotherapy with COVID-19 Mortality in Intensive Care Unit in Inpatients with Cardiovascular Diseases

Background and Objectives: To estimate the association between admission functional outcomes and exposure to physiotherapy interventions with mortality rate in intensive care unit (ICU) inpatients with cardiovascular diseases and new coronavirus disease (COVID-19). Materials and Methods: Retrospective cohort including 100 ICU inpatients (mean (standard deviation), age 75 (16) years) split into COVID-19+ or COVID-19−. The association of in-ICU death with admission functional outcomes and physiotherapy interventions was investigated using univariable and multivariable regression models. Results: In total, 42 (42%) patients tested positive for COVID-19. In-ICU mortality rate was 37%, being higher for the COVID-19+ group (odds ratio, OR (95% CI): 3.15 (1.37−7.47), p = 0.008). In-ICU death was associated with lower admission ICU Mobility Scale score (0.81 (0.71−0.91), p = 0.001). Restricted mobility (24.90 (6.77−161.94), p < 0.001) and passive kinesiotherapy (30.67 (9.49−139.52), p < 0.001) were associated with in-ICU death, whereas active kinesiotherapy (0.13 (0.05−0.32), p < 0.001), standing (0.12 (0.05−0.30), p < 0.001), or walking (0.10 (0.03−0.27), p < 0.001) were associated with in-ICU discharge. Conclusions: In-ICU mortality was higher for inpatients with cardiovascular diseases who had COVID-19+, were exposed to invasive mechanical ventilation, or presented with low admission mobility scores. Restricted mobility or passive kinesiotherapy were associated with in-ICU death, whereas active mobilizations (kinesiotherapy, standing, or walking) were associated with in-ICU discharge in this population.

Transcutaneous electrical diaphragmatic stimulation reduces the duration of invasive mechanical ventilation in patients with cervical spinal cord injury: retrospective case series

Study design

Retrospective case series.

Objectives

To compare individuals with cervical spinal cord injury (SCI) submitted to transcutaneous electrical diaphragmatic stimulation (TEDS) or a standard weaning protocol (SWP) according to the following variables: invasive mechanical ventilation (IMV) time, ventilator weaning time, intensive care unit (ICU) length of stay, and overall hospital length of stay.

Settings

Tertiary university hospital. Clinical Hospital of Campinas State University—UNICAMP—Campinas (SP), Brazil.

Methods

Retrospective case study investigating ICU patients submitted to tracheostomy due to cervical SCI at a tertiary university hospital (Clinical Hospital of Campinas State University, Brazil). Data were extracted from medical records of patients seen between January 2007 and December 2016. According to medical records, four patients were submitted to TEDS and six to a SWP. Provision of training to patients in the TEDS group was based on consensus medical decision, preference of the physical therapy team and availability of electrostimulation equipment in the ICU.

Results

Total IMV time in the TEDS and the SWP group was 33 ± 15 and 60 ± 22 days, respectively. Length of stay in ICU in the TEDS and the SWP group was 31 ± 18 and 63 ± 45 days, respectively.

Conclusion

TEDS appears to influence the duration of IMV as well as the length of stay in ICU. This physiotherapeutic intervention may be a potentially promising tool for treatment of patients with SCI. However, randomized clinical trials are warranted to support this assumption.

The Effect of Reconnection to Mechanical Ventilation for 1 Hour After Spontaneous Breathing Trial on Reintubation Among Patients Ventilated for More Than 12 Hours: A Randomized Clinical Trial

BACKGROUND

The resting of the respiratory musculature after undergoing the spontaneous breathing trial (SBT) to prevent extubation failures in critically ill patients needs to be studied further.

RESEARCH QUESTION

Is the reconnection to mechanical ventilation (MV) for 1 h after a successful SBT able to reduce the risk of reintubation?

STUDY DESIGN AND METHODS

Randomized clinical trial conducted in four ICUs between August 2018 and July 2019. Candidates for tracheal extubation who met all screening criteria for weaning were included. After achieving success in the SBT using a T-tube, the patients were randomized to the following groups: direct extubation (DE) or extubation after reconnection to MV for 1 h (R1h). The primary outcome was reintubation within 48 h.

RESULTS

Among the 336 patients studied (women, 41.1%; median age, 59 years [interquartile range, 45-70 years]), 12.9% (22/171) in the R1h group required reintubation within 48 h vs 18.2% (30/165) in the DE group (risk difference, 5.3 [95% CI, -2.49 to 13.12]; P = .18). No differences were found in mortality, length of ICU or hospital stay, causes of reintubation, or signs of extubation failure. A prespecified exploratory analysis showed that among the 233 patients (69.3%) who were ventilated for more than 72 h, the incidence of reintubation was 12.7% (15/118) in the R1h group compared with 22.6% (26/115) observed in the DE group (P = .04).

INTERPRETATION

Reconnection to MV after a successful SBT, compared with DE, did not result in a statistically significant reduction in the risk of reintubation in mechanically ventilated patients. Subgroup exploratory findings suggest that the strategy may benefit patients who were ventilated for more than 72 h, which should be confirmed in further studies.

TRIAL REGISTRY

Brazilian Clinical Trials Registry; No.: RBR-3x8nxn; URL: www.ensaiosclinicos.gov.br.

Challenges for the development of alternative low-cost ventilators during COVID-19 pandemic in Brazil

The COVID-19 pandemic has brought concerns to managers, healthcare professionals, and the general population related to the potential mechanical ventilators’ shortage for severely ill patients. In Brazil, there are several initiatives aimed at producing alternative ventilators to cover this gap. To assist the teams that work in these initiatives, we provide a discussion of some basic concepts on physiology and respiratory mechanics, commonly used mechanical ventilation terms, the differences between triggering and cycling, the basic ventilation modes and other relevant aspects, such as mechanisms of ventilator-induced lung injury, respiratory drive, airway heating and humidification, cross-contamination risks, and aerosol dissemination. After the prototype development phase, preclinical bench-tests and animal model trials are needed to determine the safety and performance of the ventilator, following the minimum technical requirements. Next, it is mandatory going through the regulatory procedures as required by the Brazilian Health Regulatory Agency (Agência Nacional de Vigilância Sanitária - ANVISA). The manufacturing company should be appropriately registered by ANVISA, which also must be notified about the conduction of clinical trials, following the research protocol approval by the Research Ethics Committee. The registration requisition of the ventilator with ANVISA should include a dossier containing the information described in this paper, which is not intended to cover all related matters but to provide guidance on the required procedures.

Factors associated with non-invasive mechanical ventilation failure in patients with hematological neoplasia and their association with outcomes

BACKGROUND

The usefulness of non-invasive mechanical ventilation (NIMV) in oncohematological patients is still a matter of debate.

AIM

To analyze the rate of noninvasive ventilation failure and the main characteristics associated with this endpoint in oncohematological patients with acute respiratory failure (ARF).

METHODS

A ventilatory support protocol was developed and implemented before the onset of the study. According to the PaO2/FiO2 (P/F) ratio and clinical judgment, patients received supplementary oxygen therapy, NIMV, or invasive mechanical ventilation (IMV).

RESULTS

Eighty-two patients were included, average age between 52.1 ± 16 years old; 44 (53.6%) were male. The tested protocol was followed in 95.1% of cases. Six patients (7.3%) received IMV, 59 (89.7%) received NIMV, and 17 (20.7%) received oxygen therapy. ICU mortality rates were significantly higher in the IMV (83.3%) than in the NIMV (49.2%) and oxygen therapy (5.9%) groups (P < 0.001). Among the 59 patients who initially received NIMV, 30 (50.8%) had to eventually be intubated. Higher SOFA score at baseline (1.35 [95% CI = 1.12-2.10], P = 0.007), higher respiratory rate (RR) (1.10 [95% CI = 1.00-1.22], P = 0.048), and sepsis on admission (16.9 [95% CI = 1.93-149.26], P = 0.011) were independently associated with the need of orotracheal intubation among patients initially treated with NIMV. Moreover, NIMV failure was independently associated with ICU (P < 0.001) and hospital mortality (P = 0.049), and mortality between 6 months and 1 year (P < 0.001).

CONCLUSION

The implementation of a NIMV protocol is feasible in patients with hematological neoplasia admitted to the ICU, even though its benefits still remain to be demonstrated. NIMV failure was associated with higher SOFA and RR and more frequent sepsis, and it was also related to poor prognosis.

Clinical study of Dysfunctional Ventilatory Weaning Response in critically ill patients

Objective:

to clinically validate the nursing diagnosis of Dysfunctional Ventilatory Weaning Response in adult patients admitted to Intensive Care Units.

Method:

a concurrent cohort performed with 93 patients admitted to Intensive Care Units. The incidence and incidence density of the diagnosis were estimated, its related factors were identified based on bivariate analysis and clinical indicators for determining its occurrence, according to the global and temporal presentation.

Results:

the overall incidence of the diagnosis was 44.09% and the incidence density was 14.49 occurrences for every 100 extubations/day. The factors related to the diagnosis were the following: age, clinical severity, fluid balance, oliguria, hemodialysis, edema in upper/lower limbs, anasarca, number of antibiotics, hypothermia, hyperthermia, amount of secretion, muscle retraction, anxiety score, heart rate, use of vasopressors and non-invasive ventilation after extubation. The clinical indicators most frequently identified for determining the diagnosis were the following: tachypnea, drop of saturation and tachycardia. Temporal progression in the severity of these manifestations was found.

Conclusion:

the Dysfunctional Ventilatory Weaning Response is a common finding in critically ill patients. Some components of the diagnosis of the NANDA-International (2018) version could be clinically validated. It is noteworthy that there are variables not yet described in the taxonomy, demonstrating the need to review this nursing diagnosis.

Characteristics and predictors of chronic critical illness in the intensive care unit

Objective

To characterize patients with chronic critical illness and identify predictors of development of chronic critical illness.

Methods

Prospective data was collected for 1 year in the intensive care unit of a general hospital in Southern Brazil. Three logistic regression models were constructed to identify factors associated with chronic critical illness.

Results

Among the 574 subjects admitted to the intensive care unit, 200 were submitted to mechanical ventilation. Of these patients, 85 (43.5%) developed chronic critical illness, composing 14.8% of all the patients admitted to the intensive care unit. The regression model that evaluated the association of chronic critical illness with conditions present prior to intensive care unit admission identified chronic renal failure in patients undergoing hemodialysis (OR 3.57; p = 0.04) and a neurological diagnosis at hospital admission (OR 2.25; p = 0.008) as independent factors. In the model that evaluated the association of chronic critical illness with situations that occurred during intensive care unit stay, muscle weakness (OR 2.86; p = 0.01) and pressure ulcers (OR 9.54; p < 0.001) had the strongest associations. In the global multivariate analysis (that assessed previous factors and situations that occurred in the intensive care unit), hospital admission due to neurological diseases (OR 2.61; p = 0.03) and the development of pressure ulcers (OR 9.08; p < 0.001) had the strongest associations.

Conclusion

The incidence of chronic critical illness in this study was similar to that observed in other studies and had a strong association with the diagnosis of neurological diseases at hospital admission and chronic renal failure in patients undergoing hemodialysis, as well as complications developed during hospitalization, such as pressure ulcers and muscle weakness.

Reduction of ventilatory time using the multidisciplinary disconnection protocol. Pilot study

Objective:

compare ventilatory time between patients with the application of a disconnection protocol, managed in a coordinated way between doctor and nurse, with patients managed exclusively by the doctor.

Method:

experimental pilot study before and after. Twenty-five patients requiring invasive mechanical ventilation for 24 hours or more were included, and the protocol-guided group was compared with the protocol-free group managed according to usual practice.

Results:

by means of the multidisciplinary protocol, the time of invasive mechanical ventilation was reduced (141.94 ± 114.50 vs 113.18 ± 55.14; overall decrease of almost 29 hours), the time spent on weaning (24 hours vs 7.40 hours) and the numbers of reintubation (13% vs 0%) in comparison with the group in which the nurse did not participate. The time to weaning was shorter in the retrospective cohort (2 days vs. 5 days), as was the hospital stay (7 days vs. 9 days).

Conclusion:

the use of a multidisciplinary protocol reduces the duration of weaning, the total time of invasive mechanical ventilation and reintubations. The more active role of the nurse is a fundamental tool to obtain better results.

Patient-ventilator asynchrony

Patient-v entilator asynchrony (PVA) is a mismatch between the patient, regarding time, flow, volume, or pressure demands of the patient respiratory system, and the ventilator, which supplies such demands, during mechanical ventilation (MV). It is a common phenomenon, with incidence rates ranging from 10% to 85%. PVA might be due to factors related to the patient, to the ventilator, or both. The most common PVA types are those related to triggering, such as ineffective effort, auto-triggering, and double triggering; those related to premature or delayed cycling; and those related to insufficient or excessive flow. Each of these types can be detected by visual inspection of volume, flow, and pressure waveforms on the mechanical ventilator display. Specific ventilatory strategies can be used in combination with clinical management, such as controlling patient pain, anxiety, fever, etc. Deep sedation should be avoided whenever possible. PVA has been associated with unwanted outcomes, such as discomfort, dyspnea, worsening of pulmonary gas exchange, increased work of breathing, diaphragmatic injury, sleep impairment, and increased use of sedation or neuromuscular blockade, as well as increases in the duration of MV, weaning time, and mortality. Proportional assist ventilation and neurally adjusted ventilatory assist are modalities of partial ventilatory support that reduce PVA and have shown promise. This article reviews the literature on the types and causes of PVA, as well as the methods used in its evaluation, its potential implications in the recovery process of critically ill patients, and strategies for its resolution.

Patient-ventilator asynchrony

Patient-v entilator asynchrony (PVA) is a mismatch between the patient, regarding time, flow, volume, or pressure demands of the patient respiratory system, and the ventilator, which supplies such demands, during mechanical ventilation (MV). It is a common phenomenon, with incidence rates ranging from 10% to 85%. PVA might be due to factors related to the patient, to the ventilator, or both. The most common PVA types are those related to triggering, such as ineffective effort, auto-triggering, and double triggering; those related to premature or delayed cycling; and those related to insufficient or excessive flow. Each of these types can be detected by visual inspection of volume, flow, and pressure waveforms on the mechanical ventilator display. Specific ventilatory strategies can be used in combination with clinical management, such as controlling patient pain, anxiety, fever, etc. Deep sedation should be avoided whenever possible. PVA has been associated with unwanted outcomes, such as discomfort, dyspnea, worsening of pulmonary gas exchange, increased work of breathing, diaphragmatic injury, sleep impairment, and increased use of sedation or neuromuscular blockade, as well as increases in the duration of MV, weaning time, and mortality. Proportional assist ventilation and neurally adjusted ventilatory assist are modalities of partial ventilatory support that reduce PVA and have shown promise. This article reviews the literature on the types and causes of PVA, as well as the methods used in its evaluation, its potential implications in the recovery process of critically ill patients, and strategies for its resolution.

Use of thoracic electrical impedance tomography as an auxiliary tool for alveolar recruitment maneuvers in acute respiratory distress syndrome: case report and brief literature review

Thoracic electrical impedance tomography is a real-time, noninvasive monitoring tool of the regional pulmonary ventilation distribution. Its bedside use in patients with acute respiratory distress syndrome has the potential to aid in alveolar recruitment maneuvers, which are often necessary in cases of refractory hypoxemia. In this case report, we describe the monitoring results and interpretation of thoracic electrical impedance tomography used during alveolar recruitment maneuvers in a patient with acute respiratory distress syndrome, with transient application of high alveolar pressures and optimal positive end-expiratory pressure titration. Furthermore, we provide a brief literature review regarding the use of alveolar recruitment maneuvers and monitoring using thoracic electrical impedance tomography in patients with acute respiratory distress syndrome.

Acute respiratory distress syndrome

Acute respiratory distress syndrome presents as hypoxia and bilateral pulmonary infiltrates on chest imaging in the absence of heart failure sufficient to account for this clinical state. Management is largely supportive, and is focused on protective mechanical ventilation and the avoidance of fluid overload. Patients with severe hypoxaemia can be managed with early short-term use of neuromuscular blockade, prone position ventilation, or extracorporeal membrane oxygenation. The use of inhaled nitric oxide is rarely indicated and both β2 agonists and late corticosteroids should be avoided. Mortality remains at approximately 30%.

The rapid shallow breathing index as a predictor of successful mechanical ventilation weaning: clinical utility when calculated from ventilator data

OBJECTIVE:

The use of the rapid shallow breathing index (RSBI) is recommended in ICUs, where it is used as a predictor of mechanical ventilation (MV) weaning success. The aim of this study was to compare the performance of the RSBI calculated by the traditional method (described in 1991) with that of the RSBI calculated directly from MV parameters.

METHODS:

This was a prospective observational study involving patients who had been on MV for more than 24 h and were candidates for weaning. The RSBI was obtained by the same examiner using the two different methods (employing a spirometer and the parameters from the ventilator display) at random. In comparing the values obtained with the two methods, we used the Mann-Whitney test, Pearson's linear correlation test, and Bland-Altman plots. The performance of the methods was compared by evaluation of the areas under the ROC curves.

RESULTS:

Of the 109 selected patients (60 males; mean age, 62 ± 20 years), 65 were successfully weaned, and 36 died. There were statistically significant differences between the two methods for respiratory rate, tidal volume, and RSBI (p < 0.001 for all). However, when the two methods were compared, the concordance and the intra-observer variation coefficient were 0.94 (0.92-0.96) and 11.16%, respectively. The area under the ROC curve was similar for both methods (0.81 ± 0.04 vs. 0.82 ± 0.04; p = 0.935), which is relevant in the context of this study.

CONCLUSIONS:

The satisfactory performance of the RSBI as a predictor of weaning success, regardless of the method employed, demonstrates the utility of the method using the mechanical ventilator.

Influence of inspiratory muscle training on weaning patients from mechanical ventilation: a systematic review

Abstract Introduction: The inability of respiratory muscles to generate force and endurance is recognized as an important cause of failure in weaning patients from invasive mechanical ventilation (IMV). Thus, inspiratory muscle training (IMT) might be an interesting treatment option for patients with prolonged IMV weaning. Objective: The aim of this systematic literature review was to evaluate the effectiveness of inspiratory muscle training in weaning patients from mechanical ventilation and to identify the most effective type of training for this particular purpose. Methods: We searched PubMed, LILACS, PEDro and Web of Science for randomized clinical trials published in English or Portuguese from January 1990 until March 2015. Results: Eighty-nine studies were identified of which five were selected. A total of 267 patients participated in the five randomized clinical trials analyzed here. IMV duration before onset of training varied greatly among subjects. Three studies performed IMT using a threshold device and two studies used adjustments of ventilator pressure sensitivity. Four studies have shown that IMT resulted in a significant increase in inspiratory maximal pressure. Only two studies, however, have reported that IMT resulted in higher success rates in weaning patients from IMV. One study has found that patients showed a shorter ventilator weaning duration after IMT. Conclusion: IMT using pressure threshold devices results in increased inspiratory muscle strength and can therefore be considered a more effective treatment option and with the potential to optimize ventilator weaning success in patients at risk of prolonged IMV.