Desvendando a técnica de compressão torácica em pacientes em ventilação mecânica: uma revisão narrativa / A deep look into the rib cage compression technique in mechanically ventilated patients: a narrative review

RESUMO O manejo deficiente das secreções é uma das complicações mais frequentes em pacientes em ventilação mecânica invasiva. A depuração das secreções por meio da fisioterapia respiratória é um aspecto crítico do tratamento desses pacientes. A compressão torácica manual é uma das técnicas de fisioterapia respiratória mais praticadas em pacientes ventilados, mas seu impacto nos desfechos clínicos permanece controverso devido a questões metodológicas e ao pouco conhecimento sobre sua ação. Nesta revisão, apresenta-se uma análise detalhada dos princípios físicos envolvidos na execução da técnica de compressão torácica. Também investigam-se os efeitos fisiológicos observados em estudos experimentais e clínicos, que mostram que o uso de compressão torácica curta e vigorosa, baseada no aumento de fluxos expiratórios (diferença de fluxo aéreo inspiratório-expiratório > 33L/minuto), pode melhorar o movimento do muco em direção à glote. Por outro lado, o uso de compressão torácica suave e gradual ao longo de toda a fase expiratória não afeta os fluxos expiratórios, resultando em efeitos ineficazes ou indesejados em alguns casos. Mais estudos fisiológicos são necessários para entender os princípios da técnica de compressão torácica em pacientes ventilados. No entanto, de acordo com as evidências, a compressão torácica tem mais benefícios potenciais do que riscos, o que incentiva sua implementação.

ABSTRACT Defective management of secretions is one of the most frequent complications in invasive mechanically ventilated patients. Clearance of secretions through chest physiotherapy is a critical aspect of the treatment of these patients. Manual rib cage compression is one of the most practiced chest physiotherapy techniques in ventilated patients; however, its impact on clinical outcomes remains controversial due to methodological issues and poor understanding of its action. In this review, we present a detailed analysis of the physical principles involved in rib cage compression technique performance, as well as the physiological effects observed in experimental and clinical studies, which show that the use of brief and vigorous rib cage compression, based on increased expiratory flows (expiratory-inspiratory airflow difference of > 33L/minute), can improve mucus movement toward the glottis. On the other hand, the use of soft and gradual rib cage compression throughout the whole expiratory phase does not impact the expiratory flows, resulting in ineffective or undesired effects in some cases. More physiological studies are needed to understand the principles of the rib cage compression technique in ventilated humans. However, according to the evidence, rib cage compression has more potential benefits than risks, so its implementation should be promoted.

Effectiveness of neuromuscular electrostimulation in COPD subjects on mechanical ventilation. A systematic review and meta-analysis

Abstract Objective: To estimate the effectiveness of Neuromuscular Electrostimulation (NMES) in adults with COPD undergoing MV. Method: A sensitive search was performed in MEDLINE, Embase, CENTRAL, CINAHL and other resources. Randomized Controlled Clinical Trials (RCTs) or non-RCTs that enrolled adults with COPD on MV due to an exacerbation of their disease were included. Two independent reviewers screened, extracted information, and assessed the risk of bias (RoB 2 tool) and the certainty of evidence (GRADE approach) from the included studies. Results: Four RCTs (144 participants) were included. Subjects who underwent NMES were able to move from bed to chair independently in less time (MD = 4.98 days less; 95% CI -8.55 to -1.47; 2 RCTs; low certainty of the evidence) and they were fewer days on MV (MD = 2.89 days less; 95% CI -4.58 to -1.21); 3 RCTs; low certainty of the evidence) than the control group. However, the effect of NMES on muscle strength is unclear (very low certainty of the evidence). Conclusions: NMES may improve functional independence and decrease MV time in adults with COPD; however, its effectiveness on muscle strength is uncertain. More and better RCTs are needed to determine with greater certainty the effectiveness of NMES in this population.

Disfunción Diafragmática en Ventilación Mecánica: Evaluación e Implicancias Clínicas / Diaphragmatic Dysfunction in Mechanical Ventilation: Evaluation and Clinical Implications

La debilidad diafragmática es un problema relevante en pacientes admitidos a la unidad de cuidados intensivos (UCI). Su presencia ha sido asociada a mayor tiempo en ventilación mecánica, weaning dificultoso, mayor riesgo de readmisión hospitalaria y mayor mortalidad. Las causas de esta debilidad son múltiples incluyendo factores relacionados a la severidad de la enfermedad, las intervenciones en la UCI y el uso de ventilación mecánica, termino conocido como miotrauma. Se han propuesto cuatro diferentes mecanismos de miotrauma relacionados a la sobre asistencia ventilatoria, baja asistencia ventilatoria, ocurrencia de contracciones diafragmáticas excéntricas y efecto de la presión espiratoria al final de espiración. Una adecuada evaluación y monitoreo de la función diafragmática es, por lo tanto, un aspecto clave que debe ser realizado al lado de la cama del paciente. La prueba de referencia para medir la función del diafragma es la presión transdiafragmática calculada como la diferencia entre la presión gástrica y presión esofágica. Adicionalmente, otras técnicas disponibles para la evaluación de la función del diafragma corresponden a la ecografía y la medición de la actividad eléctrica. Desde un punto de vista clínico, basado en la evidencia sobre disfunción diafragmática en los pacientes ventilados mecánicamente, uno de los principales desafíos actuales es poder buscar estrategias ventilatorias que incorporen protección diafragmática mientras se mantiene una ventilación protectora pulmonar. En este sentido, favorecer un nivel de esfuerzo inspiratorio adecuado junto con optimizar la interacción entre el paciente y el ventilador constituyen los principales objetivos de una ventilación diafragmática protectora.

Diaphragm weakness is a relevant problem in patients admitted to the intensive care unit (ICU). Its presence has been associated with prolonged mechanical ventilation, difficult weaning, higher risk of hospital readmission, and higher mortality. The causes of this weakness are multiple, including factors related to the severity of the disease, ICU interventions and the use of mechanical ventilation, a term known as myotrauma. Four different mechanisms of myotrauma have been proposed: 1. Ventilator over-assistance; 2. Ventilator under-assistance: 3. Eccentric diaphragm contractions: and 4. Excessive end-expiratory shortening by high PEEP. An adequate evaluation and monitoring of diaphragmatic function is, therefore, a key aspect that must be performed at the patient's bedside. The gold standard for measuring diaphragm function is transdiaphragmatic pressure calculated as the difference between gastric pressure and esophageal pressure. Furthermore, other techniques available for the evaluation of diaphragm function correspond to ultrasound and the measurement of its electrical activity. From a clinical point of view, based on diaphragmatic dysfunction evidence in mechanically ventilated patients, the main current challenge consists in applying ventilatory strategies that incorporate diaphragmatic protection while maintaining lung protective ventilation. In this sense, favoring an adequate level of inspiratory effort together with optimizing the interaction between the patient and the ventilator are the main objectives of diaphragm protective ventilation.

Efectos fisiológicos de las terapias de soporte respiratorio no invasivo y su potencial rol postextubación / Physiological effects of non-invasive respiratory support therapies and their potential post-extubation role

Posterior a una extubación programada existe un porcentaje de pacientes que fracasa y requiere reintubación (~20%), este evento es conocido como fracaso de extubación, el cual se asocia con mayor morbimortalidad. Para prevenir el fracaso de extubación se han propuesto terapias como la ventilación no invasiva (VNI) y la cánula nasal de alto flujo (CNAF). Estas terapias son capaces de entregar soporte respiratorio postextubación y justifican su uso en los efectos fisiológicos que son capaces de inducir, en dónde el impacto sobre el esfuerzo respiratorio e intercambio de gases sería fundamental. Con esta racionalidad fisiológica se han desarrollado diversos estudios en diferentes contextos clínicos, esto con el fin de dilucidar cuál terapia es la mejor alternativa. En esta revisión narrativa pretendemos describir y analizar los diversos efectos fisiológicos que induce la VNI y la CNAF

Comportamiento hemodinámico y respiratorio durante la movilización temprana de pacientes sometidos a cirugía cardíaca: Experiencia en un Hospital Público / Hemodynamic and respiratory changes during early mobilization of patients undergoing cardiac surgery: experience in a public hospital

Abstract: Objective: To describe the hemodynamic and respiratory changes during early mobilization (EM) after cardiac surgery. Methods: An analytical observational retrospective cohort study was performed in a Coronary Care Unit of a tertiary hospital. 75 patients submitted to cardiac surgery (From March 2017 up to July 2017) were included. Inclusion criteria were hemodynamic and respiratory stability before starting EM. Hemodynamic and respiratory behavior during EM were evaluated. EM was performed in 3 steps: supine, seated at the edge of the bed (SEB) and biped (BIP). Heart rate (HR), breathing rate (BR), mean arterial pressure (MAP), oxygen saturation (O2Sat) and Borg and Pain scales were evaluated. Results: Six patients, (8%) could not complete the mobilization satisfactorily, which was significantly associated to greater extracorporeal circulation time (ECC T) (p= 0.02). HR, BR, MAP Borg and Pain scales, that were significantly changed during EM, returned fully after the procedure. O2Sat was significantly increased at the end of EM (p=0.000). Prolonged ECC time predicted a 4.6 fold risk for inability to perform EM for 48 hours. Conclusion: EM of patients undergoing cardiac surgery is a safe and feasible intervention. In addition, the prolonged ECC T was observed to be a risk factor for delayed mobilization in this type of patients.