Narcotrend index indicates age-related changes during propofol induction in children

Sinikka Muente, Jaakko Klockars, Mark van Gils, C. Quandt, M. Gross, Arja Hiller, Tomi Taivainen

Research output: Contribution to journalArticleScientificpeer-review

Abstract

BACKROUND: The Narcotrend® electr oencephalogram monitor is designed to measure hypnotic state during anesthesia. We performed this study to evaluate the effectiveness and reliability of the Narcotrend monitor in assessing hypnotic state and loss of consciousness (LOC) during propofol anesthesia induction in children. METHODS: Sixty-two children, aged 1–5 (n = 17), 6–12 (n = 23), and 13–16 (n = 21) yr, scheduled for elective surgery were studied. The patients were premedicated with oral midazolam 0.5 mg/kg. After IV access, propofol target controlled infusion (TCI) was started with 0.5 μg/mL and increased by 0.5 μg/mL increments every 2 min until the child did not respond to any verbal command or physical stimuli. A manual scheme was used for children weighing <15 kg. Hypnotic state was measured every minute from the start of the propofol infusion using the University of Michigan Sedation Scale (UMSS). LOC was defined as a transition of UMSS scale value 2 to 3. The Narcotrend index (NI) was recorded before the start of induction and during the whole study period. NI values were noted simultaneously, yet independently of the sedation measurements. Prediction probability (P K) was used to assess the correspondence between NI and UMSS. Sensitivity and specificity of NI for differentiating between consciousness and unconsciousness were calculated. NI values at specific UMSS levels were compared between the different age groups and the relationships between TCI propofol concentrations and sedation levels were assessed using correlation analysis. RESULTS: A P K-value of 0.84 (95% CI [0.80–0.88]) of NI was calculated from the data for the detection of LOC. Similarly, a P K value of 0.82 (95% CI [0.78–0.86]) indicated agreement between NI and UMSS values. The average NI values differed between successive UMSS sedation levels 0 and 1 and levels 1 and 2 (P < 0.01). In the youngest age group, the NI discriminated between UMSS levels 2 and 3, in the second age group between levels 1 and 2 and 2 and 3, and in the oldest age group between 0 and 1. Furthermore, the NI values differed significantly between age groups at UMSS levels 1–4 (P < 0.005), with the NI values being higher in younger compared with older children. The average NI value at LOC was 68. For the detection of consciousness, a sensitivity of 0.67 and specificity of 0.79 were achieved. Spearman correlation coefficients indicated higher association between TCI propofol concentrations and UMSS (0.96) than between NI and UMSS (−0.68). CONCLUSIONS: During propofol induction in children, the Narcotrend electroencephalogram monitor was capable of following changes in the sedation level of children to some extent, but also had a relatively high probability (0.18) of incorrectly predicting changes in conscious state. Therefore, the monitor should not solely be used to guide sedation and anesthesia. NI was age-dependent and younger children had higher NI-values than older children at the same level of sedation.
Original languageEnglish
Pages (from-to)53-59
JournalAnesthesia and Analgesia
Volume109
Issue number1
DOIs
Publication statusPublished - 2008
MoE publication typeNot Eligible
Event7th International Symposium Memory and Awareness in Anaesthesia, 13-15 March 2008, Munich, germany -
Duration: 1 Jan 2008 → …

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Propofol
Unconsciousness
Age Groups
Hypnotics and Sedatives
Anesthesia
Consciousness
Sensitivity and Specificity
Midazolam
Electroencephalography

Keywords

  • anaesthesia
  • children
  • hypnotic state
  • narcotrend index
  • propofol

Cite this

Muente, Sinikka ; Klockars, Jaakko ; van Gils, Mark ; Quandt, C. ; Gross, M. ; Hiller, Arja ; Taivainen, Tomi. / Narcotrend index indicates age-related changes during propofol induction in children. In: Anesthesia and Analgesia. 2008 ; Vol. 109, No. 1. pp. 53-59.
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abstract = "BACKROUND: The Narcotrend{\circledR} electr oencephalogram monitor is designed to measure hypnotic state during anesthesia. We performed this study to evaluate the effectiveness and reliability of the Narcotrend monitor in assessing hypnotic state and loss of consciousness (LOC) during propofol anesthesia induction in children. METHODS: Sixty-two children, aged 1–5 (n = 17), 6–12 (n = 23), and 13–16 (n = 21) yr, scheduled for elective surgery were studied. The patients were premedicated with oral midazolam 0.5 mg/kg. After IV access, propofol target controlled infusion (TCI) was started with 0.5 μg/mL and increased by 0.5 μg/mL increments every 2 min until the child did not respond to any verbal command or physical stimuli. A manual scheme was used for children weighing <15 kg. Hypnotic state was measured every minute from the start of the propofol infusion using the University of Michigan Sedation Scale (UMSS). LOC was defined as a transition of UMSS scale value 2 to 3. The Narcotrend index (NI) was recorded before the start of induction and during the whole study period. NI values were noted simultaneously, yet independently of the sedation measurements. Prediction probability (P K) was used to assess the correspondence between NI and UMSS. Sensitivity and specificity of NI for differentiating between consciousness and unconsciousness were calculated. NI values at specific UMSS levels were compared between the different age groups and the relationships between TCI propofol concentrations and sedation levels were assessed using correlation analysis. RESULTS: A P K-value of 0.84 (95{\%} CI [0.80–0.88]) of NI was calculated from the data for the detection of LOC. Similarly, a P K value of 0.82 (95{\%} CI [0.78–0.86]) indicated agreement between NI and UMSS values. The average NI values differed between successive UMSS sedation levels 0 and 1 and levels 1 and 2 (P < 0.01). In the youngest age group, the NI discriminated between UMSS levels 2 and 3, in the second age group between levels 1 and 2 and 2 and 3, and in the oldest age group between 0 and 1. Furthermore, the NI values differed significantly between age groups at UMSS levels 1–4 (P < 0.005), with the NI values being higher in younger compared with older children. The average NI value at LOC was 68. For the detection of consciousness, a sensitivity of 0.67 and specificity of 0.79 were achieved. Spearman correlation coefficients indicated higher association between TCI propofol concentrations and UMSS (0.96) than between NI and UMSS (−0.68). CONCLUSIONS: During propofol induction in children, the Narcotrend electroencephalogram monitor was capable of following changes in the sedation level of children to some extent, but also had a relatively high probability (0.18) of incorrectly predicting changes in conscious state. Therefore, the monitor should not solely be used to guide sedation and anesthesia. NI was age-dependent and younger children had higher NI-values than older children at the same level of sedation.",
keywords = "anaesthesia, children, hypnotic state, narcotrend index, propofol",
author = "Sinikka Muente and Jaakko Klockars and {van Gils}, Mark and C. Quandt and M. Gross and Arja Hiller and Tomi Taivainen",
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Muente, S, Klockars, J, van Gils, M, Quandt, C, Gross, M, Hiller, A & Taivainen, T 2008, 'Narcotrend index indicates age-related changes during propofol induction in children', Anesthesia and Analgesia, vol. 109, no. 1, pp. 53-59. https://doi.org/10.1213/ane.0b013e3181a49c98

Narcotrend index indicates age-related changes during propofol induction in children. / Muente, Sinikka; Klockars, Jaakko; van Gils, Mark; Quandt, C.; Gross, M.; Hiller, Arja; Taivainen, Tomi.

In: Anesthesia and Analgesia, Vol. 109, No. 1, 2008, p. 53-59.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Narcotrend index indicates age-related changes during propofol induction in children

AU - Muente, Sinikka

AU - Klockars, Jaakko

AU - van Gils, Mark

AU - Quandt, C.

AU - Gross, M.

AU - Hiller, Arja

AU - Taivainen, Tomi

N1 - HUO: online ISSN 1471-6771 print ISSN 0007-0912

PY - 2008

Y1 - 2008

N2 - BACKROUND: The Narcotrend® electr oencephalogram monitor is designed to measure hypnotic state during anesthesia. We performed this study to evaluate the effectiveness and reliability of the Narcotrend monitor in assessing hypnotic state and loss of consciousness (LOC) during propofol anesthesia induction in children. METHODS: Sixty-two children, aged 1–5 (n = 17), 6–12 (n = 23), and 13–16 (n = 21) yr, scheduled for elective surgery were studied. The patients were premedicated with oral midazolam 0.5 mg/kg. After IV access, propofol target controlled infusion (TCI) was started with 0.5 μg/mL and increased by 0.5 μg/mL increments every 2 min until the child did not respond to any verbal command or physical stimuli. A manual scheme was used for children weighing <15 kg. Hypnotic state was measured every minute from the start of the propofol infusion using the University of Michigan Sedation Scale (UMSS). LOC was defined as a transition of UMSS scale value 2 to 3. The Narcotrend index (NI) was recorded before the start of induction and during the whole study period. NI values were noted simultaneously, yet independently of the sedation measurements. Prediction probability (P K) was used to assess the correspondence between NI and UMSS. Sensitivity and specificity of NI for differentiating between consciousness and unconsciousness were calculated. NI values at specific UMSS levels were compared between the different age groups and the relationships between TCI propofol concentrations and sedation levels were assessed using correlation analysis. RESULTS: A P K-value of 0.84 (95% CI [0.80–0.88]) of NI was calculated from the data for the detection of LOC. Similarly, a P K value of 0.82 (95% CI [0.78–0.86]) indicated agreement between NI and UMSS values. The average NI values differed between successive UMSS sedation levels 0 and 1 and levels 1 and 2 (P < 0.01). In the youngest age group, the NI discriminated between UMSS levels 2 and 3, in the second age group between levels 1 and 2 and 2 and 3, and in the oldest age group between 0 and 1. Furthermore, the NI values differed significantly between age groups at UMSS levels 1–4 (P < 0.005), with the NI values being higher in younger compared with older children. The average NI value at LOC was 68. For the detection of consciousness, a sensitivity of 0.67 and specificity of 0.79 were achieved. Spearman correlation coefficients indicated higher association between TCI propofol concentrations and UMSS (0.96) than between NI and UMSS (−0.68). CONCLUSIONS: During propofol induction in children, the Narcotrend electroencephalogram monitor was capable of following changes in the sedation level of children to some extent, but also had a relatively high probability (0.18) of incorrectly predicting changes in conscious state. Therefore, the monitor should not solely be used to guide sedation and anesthesia. NI was age-dependent and younger children had higher NI-values than older children at the same level of sedation.

AB - BACKROUND: The Narcotrend® electr oencephalogram monitor is designed to measure hypnotic state during anesthesia. We performed this study to evaluate the effectiveness and reliability of the Narcotrend monitor in assessing hypnotic state and loss of consciousness (LOC) during propofol anesthesia induction in children. METHODS: Sixty-two children, aged 1–5 (n = 17), 6–12 (n = 23), and 13–16 (n = 21) yr, scheduled for elective surgery were studied. The patients were premedicated with oral midazolam 0.5 mg/kg. After IV access, propofol target controlled infusion (TCI) was started with 0.5 μg/mL and increased by 0.5 μg/mL increments every 2 min until the child did not respond to any verbal command or physical stimuli. A manual scheme was used for children weighing <15 kg. Hypnotic state was measured every minute from the start of the propofol infusion using the University of Michigan Sedation Scale (UMSS). LOC was defined as a transition of UMSS scale value 2 to 3. The Narcotrend index (NI) was recorded before the start of induction and during the whole study period. NI values were noted simultaneously, yet independently of the sedation measurements. Prediction probability (P K) was used to assess the correspondence between NI and UMSS. Sensitivity and specificity of NI for differentiating between consciousness and unconsciousness were calculated. NI values at specific UMSS levels were compared between the different age groups and the relationships between TCI propofol concentrations and sedation levels were assessed using correlation analysis. RESULTS: A P K-value of 0.84 (95% CI [0.80–0.88]) of NI was calculated from the data for the detection of LOC. Similarly, a P K value of 0.82 (95% CI [0.78–0.86]) indicated agreement between NI and UMSS values. The average NI values differed between successive UMSS sedation levels 0 and 1 and levels 1 and 2 (P < 0.01). In the youngest age group, the NI discriminated between UMSS levels 2 and 3, in the second age group between levels 1 and 2 and 2 and 3, and in the oldest age group between 0 and 1. Furthermore, the NI values differed significantly between age groups at UMSS levels 1–4 (P < 0.005), with the NI values being higher in younger compared with older children. The average NI value at LOC was 68. For the detection of consciousness, a sensitivity of 0.67 and specificity of 0.79 were achieved. Spearman correlation coefficients indicated higher association between TCI propofol concentrations and UMSS (0.96) than between NI and UMSS (−0.68). CONCLUSIONS: During propofol induction in children, the Narcotrend electroencephalogram monitor was capable of following changes in the sedation level of children to some extent, but also had a relatively high probability (0.18) of incorrectly predicting changes in conscious state. Therefore, the monitor should not solely be used to guide sedation and anesthesia. NI was age-dependent and younger children had higher NI-values than older children at the same level of sedation.

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KW - children

KW - hypnotic state

KW - narcotrend index

KW - propofol

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DO - 10.1213/ane.0b013e3181a49c98

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VL - 109

SP - 53

EP - 59

JO - Anesthesia and Analgesia

JF - Anesthesia and Analgesia

SN - 0003-2999

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