Author Reply "Comment on Prediction of Successful Spontaneous Breathing Trial and Extubation of Trachea by Lung Ultrasound in Mechanically Ventilated Patients in Intensive Care".

How to cite this article: Rajbanshi LK. Author Reply "Comment on Prediction of Successful Spontaneous Breathing Trial and Extubation of Trachea by Lung Ultrasound in Mechanically Ventilated Patients in Intensive Care". Indian J Crit Care Med 2023;27(8):597-598.

Índice de respiración rápida superficial diafragmática como predictor weaning de la ventilación mecánica / Rate of rapid superficial diaphragmatic breathing as a weaning predictor of mechanical ventilation

El destete de la ventilación mecánica (VM) es un paso clave para los pacientes sometidos a VM invasiva en la unidad de cuidados intensivos (UCI). Entre las diversas herramientas destinadas a ayudar a predecir el fracaso sucesor del destete, encontramos el índice rápido de respiración superficial (RSBI por sus siglas en inglés), es decir, la relación entre la frecuencia respiratoria y el volumen corriente (Fr/Vt) medido durante una prueba de respiración espontánea (SBT por sus siglas en inglés). Objetivo: Describir el índice de respiración superficial diagramática como predictor Weaning de la ventilación mecánica. Materiales y métodos: Estudio de revisión, de tipo monográfico. Apoyado en artículos científicos, publicados en diferentes revistas indexzada en índices reconocidos. Resultado: Durante un SBT, el valor de RSBI parece ser paralelo a la evolución de la fatiga de los músculos respiratorios. Por lo tanto, se considera que el RSBI refleja la carga inspiratoria, siendo la disminución del volumen tidal junto con el aumento de frecuencia respiratoria indicativo de posible debilidad o fatiga de los músculos inspiratorios, u otros efectos fisiológicos. Conclusión: Entre los pacientes ventilados en la UCI, una alteración multifactorial del diafragma es común y puede resultar en falla del destete y prolongación de la VM invasiva; por lo tanto, evaluar la función del diafragma es un medio útil para evaluar la capacidad del paciente para tolerar la respiración espontánea(AU)

Weaning from mechanical ventilation (MV) is a key step for patients undergoing invasive MV in the intensive care unit (ICU). Among the various tools intended to help predict successor failure weaning, we found the rapid shallow breathing index (RSBI for its acronym in English), that is, the relationship between the respiratory rate and the volume current (Fr/Vt) measured during a spontaneous breathing test (SBT by its acronym in English). Objective: To describe the rate of shallow breathing Diagrammatic as a Weaning predictor of mechanical ventilation. Materials and methods: Review study, monographic type. supported by articles scientific, published in different magazines indexed in recognized indices. Result: During an SBT, the RSBI value appears to be parallel to the evolution of respiratory muscle fatigue. Therefore, it is considered that the RSBI reflects the inspiratory load, being the decrease in tidal volume together with the increased respiratory rate indicative of possible weakness or fatigue of the inspiratory muscles, or other physiological effects. Conclusion: Among the patients ventilated in the ICU, a multifactorial alteration of the diaphragm is common and can result in weaning failure and prolongation of invasive MV; by Therefore, assessing diaphragm function is a useful means of assessing the patient's ability to tolerate spontaneous breathing(AU)

Risk factors for difficult ventilatory weaning in intensive care patients with cervical cellulitis.

PURPOSE: Cervical cellulitis is an infrequent but serious infection. The management of the upper airways is difficult, at the actual time of intubation but also regarding the necessity of maintaining mechanical ventilation. The objective of this study is to identify risk factors on admission to the intensive care unit for difficult ventilatory weaning in patients with cervical cellulitis. METHODS: Between January 2013 and December 2018, this retrospective observational study was performed in an intensive care unit with 10 beds in a university hospital recognized as a reference center for the management of cellulitis. All intensive care patients receiving mechanical ventilation after surgery for cervical cellulitis were eligible. Difficult ventilatory weaning was defined as mechanical ventilation lasting more than 7 days or failure of extubation as established by the WIND 2017 study. RESULTS: We included 120 patients with severe cervical cellulitis. The median age was 43 years. Eighteen patients (16%) presented mediastinal extension. The risk factor for difficult ventilatory weaning (n = 49) in multivariate analysis was a high level of procalcitonin on admission (OR at 1.14[1.005-1.29]; p<0.042) and the protective factor was surgery in an expert center (OR at 0.11[0.026-0.47]; p<0.003). Eight patients required a tracheotomy in our study: 3 patients during surgery and at a later time for the other 5 of our 8 patients. CONCLUSION: No intensive care studies have investigated ventilatory weaning risk factors in patients with cervical cellulitis. Yet simple criteria seem to predict this risk. It is now necessary to confirm them by a multicenter prospective study.

Systematic review and meta-analysis of tracheostomy outcomes in COVID-19 patients.

A systematic review and meta-analysis of the entire COVID-19 Tracheostomy cohort was conducted to determine the cumulative incidence of complications, mortality, time to decannulation and ventilatory weaning. Outcomes of surgical versus percutaneous and outcomes relative to tracheostomy timing were also analysed. Studies reporting outcome data on patients with COVID-19 undergoing tracheostomy were identified and screened by 2 independent reviewers. Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed. Outcome data were analysed using a random-effects model. From 1016 unique studies, 39 articles reporting outcomes for a total of 3929 patients were included for meta-analysis. Weighted mean follow-up time was 42.03±26 days post-tracheostomy. Meta-analysis showed that 61.2% of patients were weaned from mechanical ventilation [95%CI 52.6%-69.5%], 44.2% of patients were decannulated [95%CI 33.96%-54.67%], and cumulative mortality was found to be 19.23% [95%CI 15.2%-23.6%] across the entire tracheostomy cohort. The cumulative incidence of complications was 14.24% [95%CI 9.6%-19.6%], with bleeding accounting for 52% of all complications. No difference was found in incidence of mortality (RR1.96; p=0.34), decannulation (RR1.35, p=0.27), complications (RR0.75, p=0.09) and time to decannulation (SMD 0.46, p=0.68) between percutaneous and surgical tracheostomy. Moreover, no difference was found in mortality (RR1.57, p=0.43) between early and late tracheostomy, and timing of tracheostomy did not predict time to decannulation. Ten confirmed nosocomial staff infections were reported from 1398 tracheostomies. This study provides an overview of outcomes of tracheostomy in COVID-19 patients, and contributes to our understanding of tracheostomy decisions in this patient cohort.

The Timed Inspiratory Effort Index as a Weaning Predictor: Analysis of Intra- and Interobserver Reproducibility.

BACKGROUND: Prolonged ventilatory weaning may expose patients to unnecessary discomfort, increase the risk of complications, and raise the costs of hospital treatment. In this scenario, indexes that reliably predict successful liberation can be helpful. OBJECTIVE: To evaluate the intra- and interobserver reproducibility of the timed inspiratory effort index as a weaning predictor. METHODS: This prospective observational study included subjects judged as able to start liberation from mechanical ventilation. For the intra-observer analysis, the same investigator performed 2 measurements in each selected patient with an interval of 30 min a rest. For interobserver analysis, 2 measurements were obtained in another sample of subjects, also with an interval of 30 min rest, but each of one performed by a different investigator. The Bland-Altman diagram, the coefficient concordance of kappa, and the Pearson correlation coefficient were used to compare the measurements. The performance of the timed inspiratory effort index was assessed by receiver operating characteristic curves. Values of P < .05 were considered significant. RESULTS: We selected 113 subjects (43 males; mean ± SD age, 77 ± 14 y). Fifty-six (49.6%) achieved successful liberation, and 33 (29%) died in the ICU. The mean ± SD duration of mechanical ventilation was 14.4 ± 6.7 d. The Bland-Altman diagrams that addressed intra- and interobservers agreement showed low variability between measurements. Values of the concordance coefficients of kappa were 0.82 (0.68-0.95) and 0.80 (0.65-0.94), and of the linear correlation coefficients, 0.86 (0.77-0.91) and 0.89 (0.82-0.93) for the intra- and interobservers measurements, respectively. The mean ± SD values for the area under the curve for each pair of the intra- and interobserver measurements were 0.96 ± 0.07 versus 0.94 ± 0.07 (P = .41) and 0.94 ± 0.05 versus 0.90 ± 0.07 (P = .14), respectively. CONCLUSIONS: The variability of the measurement of the timed inspiratory effort index by intra- and interobservers showed very high reproducibility, which reinforced the index as a sensible, accurate, and reliable outcome predictor of liberation from mechanical ventilation.

Tracheostomy prevalence at Skilled Nursing Facilities.

The incidence of chronically ill subjects with prolonged mechanical ventilation has significantly increased over the last decade. Many patients get discharge to Skilled Nursing Facilities with an artificial airway, which do not have the means to properly progress on weaning. In Portugal this prevalence is unknown. Our aim was to establish the prevalence of tracheostomized patients at SNF in the North of Portugal, characterizing these units and its population, in a cross-sectional study, through an online questionnaire answered on the same day. Of the 75 SNF, 30 answered: 13 long-term, 2 medium-term, 2 short-term, 12 had beds of both medium and long-term and 1 had the three typologies. 33 had tracheostomy ventilation (prevalence 3.36%), all admitted at long-term units, the majority transferred from previous hospital admission (n=27, 90%). Only one was under mechanical ventilation. The most frequent reason for tracheostomy placement was acute respiratory failure (n=10, 33.3%). The most commonly presented cannula was the fenestrated non-cuffed (n=17, 59%). Only 4 were performing occlusion training, 21 needed frequent secretion suctioning and 1 used the mechanical in-exsufflation. Regarding motor function, 16 (53.3%) were unable to achieve sitting balance and 20 (66.7%) had no orthostatic balance or walking ability. 14 (46.7%) had percutaneous endoscopic gastrostomy. Although low response rate may induce some bias, this study revealed a significant prevalence of tracheostomized patients at SNF. These facilities do not have the resources to safely and effectively progress on ventilatory weaning. It is essential to establish new referral criteria and create specialized weaning units.

A Intervenção dos enfermeiros de reabilitação no desmame ventilatório numa unidade de cuidados intensivos / The intervention of rehabilitation nurses in ventilatory weaning in an intensive care unit

A ventilação mecânica invasiva é uma técnica terapêutica, que permite a estabilização da pessoa em situação de falência respiratória. Mas, está associada a um conjunto de complicações: disfunção dos mecanismos de limpeza da via aérea; diminuição da expansibilidade torácica com alteração da relação ventilação/perfusão; lesão mecânica da via aérea; aumento do risco de infeção respiratória e descondicionamento dos músculos respiratórios. Para além destas complicações acrescem as sequelas associadas à sedação e à imobilidade prolongada. Tal facto, é motivo de preocupação. Assim, assume neste contexto um papel fulcral o desmame ventilatório bem-sucedido, traduzindo-se na redução do tempo de internamento nas UCI, na minimização das sequelas da ventilação mecânica e na qualidade de vida das pessoas. Por este motivo, é pertinente a elaboração de estudo de investigação como o objetivo: Conhecer a intervenção do Enfermeiro de Reabilitação no desmame ventilatório, numa unidade de cuidados intensivos num hospital da região norte. A metodologia de investigação qualitativa de caráter exploratório descritivo foi o método eleito. Para tal, foi utilizada na recolha de dados a entrevista semiestruturada e a observação não participante sistemática a todos os Enfermeiros Especialistas em Reabitação de uma unidade de cuidados intensivos de um Hospital da região Norte. Do processo da análise de conteúdo das entrevistas, emergiram cinco áreas temáticas: Intervenção do Enfermeiro de Reabilitação no processo de desmame ventilatório; Dificuldades do Enfermeiro de Reabilitação no processo de desmame ventilatório; Perceção do Enfermeiro de Reabilitação sobre o sucesso do desmame ventilatório; Pertinência da intervenção Enfermeiro de Reabilitação no processo de desmame ventilatório e Aquisição de conhecimentos específicos. Do cruzamento dos dados das entrevistas e da observação não participada, emergiram os seguintes resultados: a reabilitação motora e respiratória é uma intervenção dos enfermeiros de reabilitação no cuidado à pessoa em desmame ventilatório e é iniciada precocemente. No entanto, é necessário demonstrar evidência dos programas de reeducação funcional motora e respiratória na pessoa em desmame ventilatório. A avaliação da pessoa em desmame ventilatório é uma preocupação dos EEER e identificam-na como uma intervenção nos cuidados de enfermagem de reabilitação à pessoa em desmame ventilatório, embora pelos dados colhidos percebemos que não é realizada de forma sistematizada, tendo por base a avaliação da capacidade IV funcional, função respiratória, função muscular, qualidade de vida, ansiedade e depressão, tendo ainda em conta a sintomatologia e os meios complementares de diagnóstico. As dificuldades identificadas no estudo relativas à intervenção dos Enfermeiros de Reabilitação no desmame ventilatório prendem-se com a falta de material, ausência de um protocolo de desmame ventilatório, défice de interação entre a equipa e défice na continuidade de cuidados. Os Enfermeiros de Reabilitação têm a perceção correta sobre a importância do desmame ventilatório bem-sucedido. Referem ainda, que a sua intervenção na pessoa em desmame ventilatório manifesta-se em ganhos positivos. O processo de desmame ventilatório é uma área muito específica, como tal, a intervenção do EEER requer a aquisição de saberes nesta área desde a formação especializada, à formação contínua e no conhecimento de experiências em realidades semelhantes.

Invasive mechanical ventilation is a therapeutic technique, which allows the stabilization of the person in situation of respiratory failure. However, it is associated with a series of complications such as dysfunction of airway cleansing mechanisms, decreased thoracic expandability with altered ventilation / perfusion ratio, mechanical airway lesion, increased risk of respiratory infection, and deconditioning of the muscles respiratory. In addition to these complications, sequelae associated with sedation and prolonged immobilization are added. This is a cause for concern. Thus, the role of successful ventilatory weaning plays a key role in reducing ICU stay, minimizing the sequelae of mechanical ventilation and the quality of life of the people. For this reason, it is pertinent to elaborate a research study as the objective: To know the intervention of Rehabilitation Nursing in ventilatory weaning, in an intensive care unit in a hospital in north of the region. The qualitative research methodology of descriptive exploratory character was the elected method. For this purpose, the semi-structured interview and the systematic non-participant observation were used to collect data on all nurses who are specialists in re-opening a care unit of a Hospital in the North region. From the content analysis process of the interviews, five thematic areas emerged: Intervention of the rehabilitation nurse in the ventilatory weaning process; Difficulties of the rehabilitation nurse in the ventilatory weaning process; Rehabilitation Nurses' perception of the success of ventilatory weaning; Relevance of the rehabilitation nurse intervention in the ventilatory weaning process and Acquisition of specific knowledge. The following results emerged from the cross - referencing of interviews and non - participated observation: early motor and respiratory rehabilitation is an intervention of the rehabilitation nurses in the care of the person in ventilatory weaning. However, it is necessary to demonstrate evidence of respiratory and motor functional re-education programs in the person undergoing ventilatory weaning. The evaluation of the person in ventilatory weaning is an Rehabilitation Nurses' concern and identifies it as an intervention in the rehabilitation nursing care of the person in ventilatory weaning, although from the collected data we perceive that it is not performed in a systematized manner and based on an evaluation of the capacity functional function, respiratory function, muscular function, quality of life, anxiety and depression, taking into account the symptomatology and the complementary means of diagnosis. The difficulties identified in the study concerning the intervention of rehabilitation nurses in the ventilatory weaning were evidenced by the lack of material, absence of a weaning protocol, lack of interaction between the team and the deficit in the continuity of care. Rehabilitation Nurses have a correct understanding of the importance of successful ventilatory weaning. They also point out that their intervention in the person in ventilatory weaning manifests itself in positive gains. The intervention in the ventilatory weaning process is a very specific area of Rehabilitation Nurses' intervention, the acquisition of net area knowledge is made from specialized training, through continuous training and the search for experiences in similar realities.

Cardiac autonomic modulation during different modes of weaning of mechanical ventilation / Modulação autonômica cardíaca durante diferentes modos de desmame em ventilação mecânica

INTRODUCTION: Heart rate variability (HRV) is a noninvasive method to analyze variations of time intervals between heart beats. HRV is a promising method to analyze autonomic balance quantitatively. During the weaning process of mechanical ventilation, alterations occur in the autonomic activity. Methods to identify increased risk for weaning failure are needed. OBJECTIVE: To analyze the behavior of cardiac autonomic modulation in different phases of weaning mechanical ventilation. METHODS: Cardiorespiratory parameters (SBP, DBP, MAP, RR, SpO2) of 18 participants were collected and a cardio-frequency meter was placed. The subjects were kept in supine Fowler's position t, ventilating for 10 minutes in the assist-controlled (A/C) ventilation mode the synchronized intermittent mandatory ventilation (SIMV) mode, pressure support ventilation (PSV) 18 and 10, and with nebulization through a T-piece. At the end of all ventilator modes, the pre-specified variables were measured. The HRV parameters were analyzed in the domains of time, frequency and geometric indexes. RESULTS: There was an increase in the mean rMSSD of the A/C moment of 20.67 ± 19.36ms for the PSV 10 time 29.96 ± 21.26ms (p = 0.027), increase between the SIMV moments of 24.04 ± 18.31ms and PSV 10 to 29.96 ± 21.26ms (p = 0.042), but reduced between PSV 10 and T-Tube moments 21.22 ± 13.84ms (p = 0.035). There was an increase in the LF mean of the SIMV moments 158.46 ± 229.77ms2 and PSV 10 265.50 ± 359.88ms2 for T-tube 408.92 ± 392.77ms2 (p = 0.011 and p = 0.037 respectively). The mean LF showed a decrease between C/A and SIMV moments, respectively, 62.48 ± 17.99nu and 54.29 ± 15.29nu (p = 0.024), increase in SIMV moments 54.29 ± 15.29nu and PSV 10 55.05 ± 23.07nu for TUBE T 65.57 ± 17.08nu (p = 0.049 and p = 0.027 respectively). HF increased between SIMV moments 162.89 ± 231.19ms2 and PSV 10 247.83 ± 288.99ms2 (p = 0.020) and also between SIMV and T-Tube moments 248.28 ± 214.46 ms2 (p = 0.044). There was a reduction in mean HF between PSV 10 times 44.71 ± 22.95nu and T-tube 34.22 ± 17.03nu (p = 0.026 CONCLUSIONS: The present study showed that in comparison with spontaneous breathing, controlled breathing was associated with lower HRV during weaning from mechanical ventilation.

INTRODUÇÃO: A variabilidade da frequência cardíaca (VFC) é um método não invasivo para analisar variações de intervalos de tempo entre batimentos cardíacos. A VFC é um método promissor para analisar o balanço autonômico quantitativamente. Durante o processo de desmame da ventilação mecânica, ocorrem alterações na atividade autonômica. OBJETIVO: Analisar o comportamento da modulação autonômica da frequência cardíaca em diferentes modos do desmame da VM. MÉTODO: 18 pacientes foram estudados. Os parâmetros cardiorrespiratórios (PAS, PAD, PAM, FR, SpO2) iniciais e finais foram registrados em uma ficha. Um cardiofrequencimetro foi posicionado (relógio no punho e cinta no tórax). Os pacientes foram mantidos em decúbito Fowler e permaneceram 10' em cada modo ventilatório (A/C, SIMV, PSV 18 e 10 e nebulização com Tubo T). Os sinais captados pelo cardiofrequencimetro foram analisados através do software Kubios®. RESULTADOS: Os parâmetros da Variabilidade da Frequência Cardíaca foram analisados nos domínios do tempo, frequência e índices geométricos. Houve aumento na média rMSSD - modulação parassimpática, do momento A/C para o momento PSV 10 (p=0,027), aumento entre os momentos SIMV e PSV 10 (p=0,042), mas reduziu entre os momentos PSV 10 e TUBO T (p=0,035). Houve aumento na média do LF (low frequency) -modulação simpática, dos momentos SIMV e PSV 10 para TUBO T (p=0,011 e p=0,037). A média de LF apresentou queda entre os momentos A/C e SIMV (p=0,024), aumento nos momentos SIMV e PSV 10 para TUBO T (p =0,049 e p=0,027). HF (high frequency) - modulação simpática aumentou entre os momentos SIMV e PSV 10 (p=0,020) e também entre os momentos SIMV e TUBO T (p=0,044). Houve redução na média HF entre os momentos PSV e TUBO T (p=0,026). CONCLUSÃO: Modos controlados apresentaram diminuição da VFC e maior predomínio simpático em relação a modos espontâneos.

What are the perspectives for ventilated tetraplegics? A French retrospective study of 108 patients with cervical spinal cord injury.

OBJECTIVE: Tetraplegic patients are often difficult to manage in intensive care units (ICU). The aim of our study was to calculate the incidence of patients in ICU with cervical spinal cord injury with special focus on tetraplegic patients on ventilation support and their future perspectives. MATERIALS AND METHODS: This retrospective study included patients with cervical spinal cord injury in Upper Normandy, between 2002 and 2012. Data analyzed included age, sex, past medical history, date of onset of quadriplegia, level of neurological involvement, AIS grade, and ventilatory status. RESULTS: One hundred and eight patients were included (49.0 ± 21.1 years). The most common etiology was fall (50 patients [46.3%]). Incidence was calculated at 12.7 per one million inhabitants. Tracheotomy was performed in 40.7% of patients. Long-term mechanical ventilation was required for 6.5%. At the end of the study, 9 patients (9.6%) were permanently hospitalized, 61 patients (64.9%) had returned home but none of the four ventilated patients had been discharged. CONCLUSION: The conclusion of this work is that the future of highly tetraplegic patients is compromised, especially for those who remain reliant on mechanical ventilation.

Low pressure support changes the rapid shallow breathing index (RSBI) in critically ill patients on mechanical ventilation / Baixos níveis de pressão de suporte alteram o índice de respiração rápida e superficial (IRRS) em pacientes graves sob ventilação mecânica

BACKGROUND: The rapid shallow breathing index (RSBI) is the most widely used index within intensive care units as a predictor of the outcome of weaning, but differences in measurement techniques have generated doubts about its predictive value. OBJECTIVE: To investigate the influence of low levels of pressure support (PS) on the RSBI value of ill patients. METHOD: Prospective study including 30 patients on mechanical ventilation (MV) for 72 hours or more, ready for extubation. Prior to extubation, the RSBI was measured with the patient connected to the ventilator (DragerTM Evita XL) and receiving pressure support ventilation (PSV) and 5 cmH2O of positive end expiratory pressure or PEEP (RSBI_MIN) and then disconnected from the VM and connected to a Wright spirometer in which respiratory rate and exhaled tidal volume were recorded for 1 min (RSBI_ESP). Patients were divided into groups according to the outcome: successful extubation group (SG) and failed extubation group (FG). RESULTS: Of the 30 patients, 11 (37%) failed the extubation process. In the within-group comparison (RSBI_MIN versus RSBI_ESP), the values for RSBI_MIN were lower in both groups: SG (34.79±4.67 and 60.95±24.64) and FG (38.64±12.31 and 80.09±20.71; p<0.05). In the between-group comparison, there was no difference in RSBI_MIN (34.79±14.67 and 38.64±12.31), however RSBI_ESP was higher in patients with extubation failure: SG (60.95±24.64) and FG (80.09±20.71; p<0.05). CONCLUSIONS: In critically ill patients on MV for more than 72h, low levels of PS overestimate the RSBI, and the index needs to be measured with the patient breathing spontaneously without the aid of pressure support.

CONTEXTUALIZAÇÃO: O índice de respiração rápida e superficial (IRRS) tem sido o mais utilizado dentro das unidades de terapia intensiva (UTIs) como preditor do resultado do desmame, porém diferenças no método de obtenção têm gerado dúvidas quanto a seu valor preditivo. OBJETIVO: Verificar a influência de baixos níveis de pressão de suporte (PS) no valor do IRRS em pacientes graves. MÉTODO: Estudo prospectivo, incluindo 30 pacientes sob ventilação mecânica (VM) por 72 horas ou mais, prontos para extubação. Anteriormente à extubação, o IRRS foi obtido com o paciente conectado ao ventilador Evita-XL da DragerTM recebendo pressão de suporte ventilatório (PSV) e PEEP=5 cmH2O (IRRS_MIN) e, logo após, desconectado da VM e conectado a um ventilômetro de WrightTM, onde sua frequência respiratória e o volume corrente exalado eram registrados durante 1 minuto (IRRS_ESP). Os pacientes foram divididos de acordo com o desfecho em grupo sucesso extubação (GS) e grupo insucesso extubação (GI). RESULTADOS: Dos 30 pacientes, 11 (37%) falharam no processo de extubação. Na comparação intragrupos (IRRS_MIN x IRRS_ESP), os valores foram menores para o IRRS_MIN em ambos os grupos: GS (34,79±4,67 e 60,95±24,64) e GI (38,64±12,31 e 80,09±20,71) (p<0,05). Na comparação intergrupos não houve diferença entre IRRS_MIN (34,79±14,67 e 38,64±12,31), por outro lado, IRRS_ESP foi maior nos pacientes com falha na extubação: GS (60,95±24,64) e GI (80,09±20,71) (p<0,05). CONCLUSÃO: Em pacientes graves e sob VM acima de 72 horas, níveis mínimos de PS superestimam o IRRS, sendo necessária sua obtenção com o paciente respirando de forma espontânea sem o auxílio de PS.