Impact of extended monitoring-guided intensive care on outcome after severe traumatic brain injury: A prospective multicentre cohort study (PariS-TBI study)

Trending Ability of End-Tidal Capnography Monitoring During Mechanical Ventilation to Track Changes in Arterial Partial Pressure of Carbon Dioxide in Critically Ill Patients With Acute Brain Injury: A Monocenter Retrospective Study

BACKGROUND

Changes in arterial partial pressure of carbon dioxide (Pa co2 ) may alter cerebral perfusion in critically ill patients with acute brain injury. Consequently, international guidelines recommend normocapnia in mechanically ventilated patients with acute brain injury. The measurement of end-tidal capnography (Et co2 ) allows its approximation. Our objective was to report the agreement between trends in Et co2 and Pa co2 during mechanical ventilation in patients with acute brain injury.

METHODS

Retrospective monocenter study was conducted for 2 years. Critically ill patients with acute brain injury who required mechanical ventilation with continuous Et co2 monitoring and with 2 or more arterial gas were included. The agreement was evaluated according to the Bland and Altman analysis for repeated measurements with calculation of bias, and upper and lower limits of agreement. The directional concordance rate of changes between Et co2 and Pa co2 was evaluated with a 4-quadrant plot. A polar plot analysis was performed using the Critchley methods.

RESULTS

We analyzed the data of 255 patients with a total of 3923 paired ΔEt co2 and ΔPa co2 (9 values per patient in median). Mean bias by Bland and Altman analysis was -8.1 (95 CI, -7.9 to -8.3) mm Hg. The directional concordance rate between Et co2 and Pa co2 was 55.8%. The mean radial bias by polar plot analysis was -4.4° (95% CI, -5.5 to -3.3) with radial limit of agreement (LOA) of ±62.8° with radial LOA 95% CI of ±1.9°.

CONCLUSIONS

Our results question the performance of trending ability of Et co2 to track changes in Pa co2 in a population of critically ill patients with acute brain injury. Changes in Et co2 largely failed to follow changes in Pa co2 in both direction (ie, low concordance rate) and magnitude (ie, large radial LOA). These results need to be confirmed in prospective studies to minimize the risk of bias.

The ICEBERG: a score and visual representation to track the severity of traumatic brain injury: design principles and preliminary results

BACKGROUND

Establishing neurological prognoses in traumatic brain injury (TBI) patients remains challenging. To help physicians in the early management of severe TBI, we have designed a visual score (ICEBERG score) including multimodal monitoring and treatment-related criteria. We evaluated the ICEBERG scores among patients with severe TBI to predict the 28-day mortality and long-term disability (Extended Glasgow Outcome Score (GOSE) at 3 years). Additionally, we made a preliminary assessment of the nurses and doctors on the uptake and reception to the use of the ICEBERG visual tool.

METHODS

This study was part of a larger prospective cohort study of 207 patients with severe TBI in the Parisian region (PariS-TBI study). The ICEBERG score included 6 variables from multimodal monitoring and treatment-related criteria: cerebral perfusion pressure (CPP), intracranial pressure (ICP), body temperature, sedation depth, arterial partial pressure of CO2 and blood osmolarity. The primary outcome measures included the ICEBERG score and its relationship with hospital mortality and GOSE.

RESULTS

The hospital mortality was 21% (45/207). The ICEBERG score baseline value and changes during the 72nd first hours were more strongly associated with TBI prognosis than the ICEBERG parameters measured individually. Interestingly, when the clinical and CT parameters at admission were combined with the ICEBERG score at 48 h using a multimodal approach, the predictive value was significantly increased (AUC = 0.92). Furthermore, comparing the ICEBERG visual representation with the traditional numerical readout revealed that changes in patient vitals were more promptly detected using ICEBERG representation (p < 0.05).

CONCLUSIONS

The ICEBERG score could represent a simple and effective method to describe severity in TBI patients, where a high score is associated with increased mortality and disability. Additionally, ICEBERG representation could enhances the recognition of unmet therapeutic goals and dynamic evolution of the patient's condition. These preliminary results must be confirmed in a prospective manner.

STUDY TYPE

Prognostic.

LEVEL OF EVIDENCE

Level III.

Does the use of indirect calorimetry change outcome in the ICU? Yes it does

PURPOSE OF REVIEW

To review the recent findings on metabolic monitoring and possible beneficial effects of an adequate nutrition therapy, based on indirect calorimetry as the golden standard to predict energy expenditure.

RECENT FINDINGS

in the last decades, major steps are taken in the field of metabolism and nutrition, evolving from nutrition as a baseline support to a therapeutic intervention. The aspect of energy expenditure is of cardinal importance, and technical possibilities have impressively improved: from the first 'calorimetre' in 1789 to the new generation, clinical applicable indirect calorimeters and the high accuracy and easy use model reaching high technology readiness level [Oshima et al. (2017). Clin Nutr 36:651]. Several recent studies provide information on the technique of metabolic monitoring itself and the positive effects of implementation of the tool in a high-end nutritional care plan [Oshima et al. (2017). Clin Nutr 36:651]. The combination of correct energy provision and protein prescription has shown benefits, and mortality of ICU patients is related to the amount of energy provided [Zusman et al. (2016). Crit Care 20:367]. The use of a monitor per se will not change outcome. Optimal dosing of artificial nutrition can be achieved by the use of a parameter acquired by a measurement instead of by inaccurate equations. In the era of precision medicine, this approach has shown positive effects on outcome. Moreover, above all, the concept of metabolic monitoring of the critically ill is just an issue of common sense.

SUMMARY

Metabolic monitoring by indirect calorimetry is achieving a level in which it can be implemented in critical care practice. Evidence is available to prove that by guiding your nutritional therapy by measured values, it will change outcome of critically ill patients.