Validation of Uncalibrated Cardiac Output Measurement With LiDCOrapid in the Resuscitation of Critically Ill Patients With Septic Shock: A Prospective Cross-sectional Study.

Transthoracic echocardiography (TTE) has been used as a reference technique for CO measurement and its accuracy has been adequate for many clinical uses. TTE is painless, safe and non-invasive. Some drawbacks of TTE are being expensive, bulky and needs advanced training.

Currently, due to increased interest in minimally invasive hemodynamic monitoring, multiple new methods have become commercially available to assess CO: the arterial pulse aortic flow, bioreactance, and bioimpedance.

One of these new devices is LiDCOrapid (LiDCO Ltd, Cambridge, UK). It is a new, minimally invasive monitor which estimates beat-by-beat CO and fluid responsiveness from the arterial waveform.

It has been validated after vascular, urological and thoracic surgery and shows good agreement with the PA catheter in swine, in patients with normal left ventricular systolic function and in patients with vasodilatation. However, LiDCO has not yet been validated in patients with septic shock. Therefore, the aim of this study is to validate LiDCOrapid parameters in septic shock patients using TTE derived parameters as the non-invasive reference.

Obtaining a patient's cardiac output (CO) could contribute to optimized, safe hemodynamic control. Accurate CO measurements can serve as a guide for resuscitation therapy, catecholamine use, differential diagnosis, and intervention during a circulatory failure. Although the thermodilution technique via a pulmonary artery catheter (PAC) has an invasive and intermittent, it remains the gold standard for CO measurements.

Previously monitoring of CO required invasive and costly devices limiting their use to intensive care setting. More recently ultrasound is increasingly being used and offers a range of non-invasive tools to estimate CO.

Transthoracic echocardiography (TTE) has been used as a reference technique for CO measurement and its accuracy has been adequate for many clinical uses. TTE is painless, safe and non-invasive. Some drawbacks of TTE are being expensive, bulky and needs advanced training.

Currently, due to increased interest in minimally invasive hemodynamic monitoring, multiple new methods have become commercially available to assess CO: the arterial pulse aortic flow, bioreactance, and bioimpedance.

One of these new devices is LiDCOrapid (LiDCO Ltd, Cambridge, UK). It is a new, minimally invasive monitor which estimates beat-by-beat CO and fluid responsiveness from the arterial waveform.

It has been validated after vascular, urological and thoracic surgery and shows good agreement with the PA catheter in swine, in patients with normal left ventricular systolic function and in patients with vasodilatation. However, LiDCO has not yet been validated in patients with septic shock. Therefore, the aim of this study is to validate LiDCOrapid parameters in septic shock patients using TTE derived parameters as the non-invasive reference.

Eligibility Criteria:
Inclusion Criteria:

1. Age \> 18 years.
2. Patients admitted to ICU with septic shock

Exclusion Criteria:

1. Patients with poor Echo window.
2. If they presented with a history of heart failure, valvular disease or arrhythmias.