Caveats of Bispectral Index Monitoring in the Pediatric Population

Nurse perception of Bispectral Index monitoring as an adjunct to sedation scale assessment in the critically ill paediatric patient

BACKGROUND

Reliability of clinical scales and haemodynamic variables for assessing sedation depth in critically children is limited, particularly for those receiving neuromuscular blocking agents (NMBAs).

OBJECTIVE

To introduce and integrate the use of Bispectral Index (BIS) monitoring as adjunct to sedation scale assessment in intubated mechanically ventilated Paediatric Intensive Care Unit (PICU) patients.

METHODS

Quality improvement intervention including: BIS education for all PICU nurses; 8-week implementation of BIS monitoring guided by Paediatric BIS Sedation Protocol; evaluation by convenience sample of nurses (n=17).

MEASUREMENTS

15-Item survey assessing perceptions of BIS attributes was given to nurses after first 4 BIS encounters; nurse comments and project coordinator observations were recorded.

FINDINGS

Survey data (intermediate reliability and nurse attitude ratings and low ratings on other attributes; little change over time) revealed nurses' reservations about the usefulness of BIS as an adjunct to sedation scales, but qualitative data indicated that they valued BIS for assessing sedation depth in children receiving NMBAs.

CONCLUSIONS

Post-intervention, BIS monitoring was adopted in PICU for children receiving NMBAs. One year later, this practice is sustained, and the percentage of BIS-monitored patients has increased. Guidelines addressing the use of BIS in patients not receiving paralytics are needed.

An observational study exploring amplitude-integrated electroencephalogram and spectral edge frequency during paediatric anaesthesia

Processed electroencephalography is used in adults to guide anaesthesia, but the algorithms used may not apply to infants. Knowledge of infants' electroencephalogram (EEG) responses to anaesthetics is fragmentary. An earlier pilot study suggested amplitude-integrated EEG (aEEG) may be a useful measure of anaesthetic effect. The aim of this study was to determine how aEEG changes between awake and anaesthetised children of varying ages and to compare the response to that seen with Spectral Edge Frequency 90% (SEF90). A prospective observational study of children receiving a general anaesthetic was conducted. Anaesthetic regimen remained at the discretion of the treating anaesthetist. EEG data were collected using the BrainZ ReBrim(TM) monitor using forehead and biparietal montages. SEF90 and aEEG were compared across age groups, EEG montage and between awake and anaesthetised states. A total of 178 children (aged 24 days to 14 years) were recruited. All aEEGs were greater during anaesthesia compared to when awake and this difference varied with age. Only children older than two years showed lower SEF90 while anaesthetised compared to when awake. SEF90 from children younger than six months was higher during anaesthesia compared to when awake. Analysis of parietal and forehead EEG montages revealed age-related differences. These findings suggest that SEF90 and aEEG can discriminate between awake and anaesthetised states in older children. In younger children aEEG changes are less pronounced and SEF90 either cannot discriminate between states or responds paradoxically. The aEEG may be marginally better than other EEG parameters in measuring anaesthetic depth in children.

Index of consciousness and bispectral index values are interchangeable during normotension and hypotension but not during non pulsatile flow state during cardiac surgical procedures: a prospective study

OBJECTIVES

Awareness under anesthesia is an avoidable complication during general anesthesia. Anesthetic depth monitors assist anesthesiologists in providing appropriate levels of anesthesia. Index of consciousness monitoring is a recently introduced monitor in the array of anesthesia depth monitors. The objective of this study was to assess the interchangeability of bispectral index, which is already in clinical use and the recently introduced index of consciousness techniques. The other objective was to assess this interchangeability during normotension, hypotension and during pulseless state in patients undergoing coronary artery bypass graft surgery. This study is a prospective observational study, conducted in a tertiary referral hospital.

MEASUREMENTS AND MAIN RESULTS

Fifteen cardiac surgical patients undergoing off pump and conventional coronary artery bypass under cardiopulmonary bypass participated in the study. Bispectral index and index of consciousness monitoring were carried out simultaneously during various stages of consciousness, and assessed for interchangeability. Bland Altman plotting and 'mountain plot' were used to assess the interchangeability. Eleven in the cohort underwent off pump and the rest (n = 4) conventional coronary artery bypass surgery under cardiopulmonary bypass. A set of 887 data were obtained during the study period. The data were classified as those obtained during normotension, hypotension and pulseless state during cardiopulmonary bypass.

RESULTS

732 sets of data were obtained during normotension, 84 during hypotension and 71 during cardiopulmonary bypass. Overall interchangeability was good, suggested by low bias (0.96), high precision (0.54), r value of 0.7 and P value of <0.0001. It was found that the data obtained during normotension was also interchangeable, suggested by low bias (0.8), high precision (0.54) and r value of 0.7. The data obtained during hypotension was not as highly interchangeable as during normotension-bias 0.4, precision 1.66 and r value of 0.7. The analysis of value during cardiopulmonary bypass suggested non interchangeability (bias 3.87, precision 3.05, r value 0.3 and P value = 0.0067.

CONCLUSIONS

The bispectral index and index of consciousness values may be interchangeable. The interchangeability is better appreciated during normotension and hypotension but not during non pulsatile state of cardiopulmonary bypass.