AIMS AND OBJECTIVES

The purpose of this study is to assess serial changes in diaphragm function of GBS patients measured by ultrasonography during their course in the ICU and assess its usefulness in predicting the weaning success.

PRIMARY OBJECTIVES

• To estimate the diaphragm thickness, DTF, excursion, and velocity of contraction measured by ultrasound at ICU admission in patients with GBS requiring tracheal intubation and MV

SECONDARY OBJECTIVES

• To determine the effect of changes in diaphragm measurements by ultrasound on the weaning success.
• To determine the effect of baseline diaphragm parameters by ultrasound on the duration of MV and ICU stay.

METHODOLOGY

Study design: A prospective, observational cohort study 

Study site: Neuro ICUs of National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru 

Duration of study: 24 months 

Expected sample size:  All consequent patients meeting inclusion criteria will be recruited during the study period. We expect an annual admission of 30 to 40 patients with GBS to ICU during the study period.

 Inclusion Criteria

·      Patients aged 18 to 70 years, fulfilling the National Institute of Neurological Disorders and Stroke (NINDS) criteria for GBS and Brighton level of certainty of diagnosis of one or two.

·      Patients requiring ICU admission

Exclusion Criteria

• Refusal of consent
• Patients with cardiac failure, renal or liver failure 
• Preexisting uni- or bilateral diaphragmatic paralysis
• Severe sepsis with inotropic support 

STUDY PROTOCOL

This study will be a prospective observational study done in patients with GBS admitted to Neuro ICUs at NIMHANS. The institutional ethical committee approval and informed consent from the patient’s guardian will be obtained before recruiting patients. All patients will be managed using standard practice guidelines with plasmapheresis or intravenous immunoglobulins based on the feasibility with a multidisciplinary team involving a neurologist and intensivist on admission to the ICU. Demographic details such as gender, age on admission, underlying co-morbidities, reasons for tracheal intubation, and duration of MV will be recorded. The right hemidiaphragm will be assessed ultrasonographically, and the following parameters: DTF, diaphragm thickness (DT), diaphragmatic excursion (DE), and peak velocity of the diaphragm during cough expiration will be recorded. Ultrasonographic assessment of the diaphragm will be done on day-1 of ICU admission. If the patient needs MV, then another set of diaphragm assessments will be carried out after the initiation of MV. A subsequent assessment will be done once a week until the patient is successfully weaned off the ventilator. In mechanically ventilated patients, all measurements will be performed in the semirecumbent position and connected to the ventilator in pressure support mode with a pressure support setting of 8-10 cmH₂O and physiological (0-5 cmH₂O) positive end-expiratory pressure. Diaphragmatic assessment will also be done during the first spontaneous breathing trial (SBT) of 30 minutes. Patients will be disconnected from the ventilator. The first diaphragmatic assessment will be done 5 minutes after disconnection and later at the end of the 30 minutes before connecting back to the ventilator. Successful weaning will be defined as the ability to maintain spontaneous breathing without ventilatory support for > 24 hours. The time taken for successful weaning from initiation of 1^st SBT of 30 minutes will be noted. We will monitor the diaphragmatic parameters till a mximum period of 8 weeks from the ICU admission. In our ICU the duration of stay of GBS patients range from 9-45 days in the last six months. Patinets who require very prolonged ICU stay (beyond 8 weeks) will be excluded from the analysis due to deficient follow up ultrasonographic scans for the diaphragmatic function.