Uso da tomografia de impedância elétrica associado a dados clínicos e ventilatórios para avaliação do processo de desmame da ventilação mecânica de pacientes com SARA

Base teórica: A síndrome da angustia respiratória aguda (SARA) é caracterizada por intensa resposta inflamatória e a ventilação mecânica (VM) protetora é fundamental. A presença da ventilação espontânea tem efeitos benéficos, porém em casos mais graves pode ser deletéria. A repercussão da ventilação espontânea durante o desmame da VM dos pacientes com SARA ainda é pouco entendida e estudada. Objetivo: Avaliar o desmame da VM em pacientes com SARA através da tomografia de impedância elétrica (TIE) associado a parâmetros clínicos e ventilatórios. Métodos: Estudo de coorte prospectivo de pacientes com SARA que tiveram critérios de melhora e foram definidos pela equipe assistente aptos para suspender o uso de bloqueador neuromuscular (BNM) e sedativos e iniciar o desmame da VM. Os dados da TIE e da mecânica pulmonar foram coletados em quatro momentos: basal (Tpre) e após 30 minutos (T30min), 2 horas (T2h) e 24 horas (T24h) após a troca do modo ventilatório controlado (VCV ou PCV) para modo ventilatório espontâneo (PSV). Resultados: o estudo incluiu 25 pacientes entre julho/2017 e fevereiro/2019. Os pacientes foram divididos conforme o tipo de desmame: 09 simples, 08 difícil e 08 prolongado. A duração da VM, delirium, agitação, fraqueza adquirida na UTI, traqueostomia, tempo de internação na UTI foram significantemente maiores no grupo de desmame difícil e prolongado. O volume corrente (VC) e a driving pressure (ΔP) aumentaram significantemente durante mudança do modo ventilatório controlado para espontâneo no grupo de desmame quando 8 comparado com o desmame simples (p tempo=0,0001). Os pacientes com desmame prolongado apresentaram maiores volumes pulmonares após o início da ventilação espontânea(p=0,02). Os pacientes com desmame prolongado tiveram uma tendência de maior de ventilação em regiões posteriores e redução da relação ventral/dorsal (V/D) visualizados pela TIE. Conclusão: O desmame da VM de pacientes com SARA tem elevada proporção de desmame difícil e prolongado associados com piores desfechos clínicos. As alterações pulmonares visualizada através da TIE e da avaliação da mecânica pulmonar mostraram ser relevantes no grupo de desmame prolongado da VM e poderiam ser monitorizadas rotineiramente. Mais estudos poderiam ser realizados para avaliar a ventilação espontânea e o desmame da VM em pacientes com SARA para continuar a proteger os pulmões.Background: The acute respiratory distress syndrome (ARDS) is characterized by an intense inflammatory response and protective mechanical ventilation (MV) is essential. The presence of spontaneous breathing has beneficial effects, however, it can be harmful in more severe cases. The repercussion of spontaneous breathing and its repercussion during weaning from MV in patients with ARDS is still poorly understood and studied. Objective: Evaluate weaning from MV in patients with ARDS using electrical impedance tomography (EIT) with clinical and ventilatory parameters. Methods: Prospective cohort study of patients with ARDS who presented improvement criteria and were judged by the attending team to be able to suspend the use of neuromuscular blocker (NMB) and sedatives, and start weaning from MV. The EIT and pulmonary mechanics data were collected at baseline (Tpre) and after 30 minutes (T30min), 2 hours (T2h) and 24 hours (T24h) after changed from controlled mode (VCV or PCV) to spontaneous mode (PSV). Results: The study included 25 patients between July,2017 and February,2019. The patients were 09 simple, 08 difficult and 08 prolonged weaning. The duration of MV, delirium, agitation, intensive care unit–acquired weakness (ICU-AW), tracheostomy, length of stay (LOS) and mortality of the ICU were higher difficult and prolonged weaning group. The tidal volume (TV) and driving pressure(ΔP) increased when changing from controlled to spontaneous mode, mainly in the prolonged weaning group when compared with simple weaning group (p time=0.0001). The patients with prolonged weaning presented larger total volumes after begin of the spontaneous ventilation (p=0.02). The prolonged 10 weaning group had a tendency more posterior region ventilation and reduction of the ventral/dorsal(V/D) ratio visualized by EIT. Conclusion: The weaning from MV of patients with ARDS has a high proportion of difficult and prolonged weaning associated with worse clinical outcomes. The pulmonary changes seen by EIT and assessment of pulmonary mechanics showed to be relevant in the prolonged and difficult weaning group and could be monitored routinely. Further studies should be realized to evaluate the spontaneous breathing and weaning from MV in ARDS to continue to protect the lung

Weaning from mechanical ventilation in ARDS : aspects to think about for better understanding, evaluation, and management

Acute respiratory distress syndrome (ARDS) is characterized by severe inflammatory response and hypoxemia. The use of mechanical ventilation (MV) for correction of gas exchange can cause worsening of this inflammatory response, called “ventilatorinduced lung injury” (VILI). The process of withdrawing mechanical ventilation, referred to as weaning from MV, may cause worsening of lung injury by spontaneous ventilation. Currently, there are few specific studies in patients with ARDS. Herein, we reviewed the main aspects of spontaneous ventilation and also discussed potential methods to predict the failure of weaning in this patient category. We also reviewed new treatments (modes of mechanical ventilation, neuromuscular blocker use, and extracorporeal membrane oxygenation) that could be considered in weaning ARDS patients from MV

How Medical Conditions Affect the Weaning of Mechanical Ventilation

Weaning from mechanical ventilation is a common process in critically ill patients and its failure is related to worsening outcomes. A better understanding of the subject is necessary to change these unfavorable results. This chapter will review the approach to weaning from mechanical ventilation in special groups of critically ill patients. The chapter will also review the causes of failure to wean from MV along with strategies for improving evaluation and approach of the patient with difficult and prolonged weaning from mechanical ventilation. Therefore, the presence of this topic in a book on mechanical ventilation is fundamental and relevant

Mechanical ventilation in patients in the intensive care unit of a general university hospital in southern Brazil: an epidemiological study

OBJECTIVES: To determine the characteristics, the frequency and the mortality rates of patients needing mechanical ventilation and to identify the risk factors associated with mortality in the intensive care unit (ICU) of a general university hospital in southern Brazil. METHOD: Prospective cohort study in patients admitted to the ICU who needed mechanical ventilation for at least 24 hours between March 2004 and April 2007. RESULTS: A total of 1,115 patients admitted to the ICU needed mechanical ventilation. The mortality rate was 51%. The mean age (± standard deviation) was 57±18 years, and the mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 22.6±8.3. The variables independently associated with mortality were (i) conditions present at the beginning of mechanical ventilation, age (hazard ratio: 1.01;

Leucoencefalite hemorrágica aguda associada à COVID-19

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Vitamin D deficiency is independently associated with mortality among critically ill patients

OBJECTIVE: Studies suggest an association between vitamin D deficiency and morbidity/mortality in critically ill patients. Several issues remain unexplained, including which vitamin D levels are related to morbidity and mortality and the relevance of vitamin D kinetics to clinical outcomes. We conducted this study to address the association of baseline vitamin D levels and vitamin D kinetics with morbidity and mortality in critically ill patients. METHOD: In 135 intensive care unit (ICU) patients, vitamin D was prospectively measured on admission and weekly until discharge from the ICU. The following outcomes of interest were analyzed: 28-day mortality, mechanical ventilation, length of stay, infection rate, and culture positivity. RESULTS: Mortality rates were higher among patients with vitamin D levels ;12 ng/mL) (32.2% vs. 13.2%), with an adjusted relative risk of 2.2 (95% CI 1.07-4.54; p< 0.05). There were no differences in the length of stay, ventilation requirements, infection rate, or culture positivity. CONCLUSIONS: This study suggests that low vitamin D levels on ICU admission are an independent risk factor for mortality in critically ill patients. Low vitamin D levels at ICU admission may have a causal relationship with mortality and may serve as an indicator for vitamin D replacement among critically ill patients

Acetazolamide intoxication in an elderly patient with diabetes and chronic renal failure after cataract surgery

Carbonic anhydrase inhibitors, such as acetazolamide, are widely used in the treatment of open-angle glaucoma. Severe metabolic acidosis is a rare complication of acetazolamide use, and life-threatening acidosis occurs most commonly in elderly patients, in patients with advanced renal failure, and in patients with diabetes. We describe an unusual case of an elderly patient with diabetic nephropathy and chronic renal failure who presented to the emergency department with severe metabolic acidosis and coma after exposure to high doses of acetazolamide in the postoperative period of ophthalmic surgery. As symptoms of acetazolamide intoxication and uremia are similar, high suspicion is required to detect excessive plasma drug concentrations and intoxication in patients presenting with concomitant uremia. Clinical symptoms are potentially reversible with prompt diagnosis and treatment, including supportive treatment, bicarbonate therapy, and renal replacement therapy. Hemodialysis is particularly helpful in the management of acetazolamide overdose as the medication is dialyzable