Optimal propofol induction dose in morbidly obese patients: A randomized controlled trial comparing the bispectral index and lean body weight scalar

  • Yamini Subramani
  • Waleed Riad
  • Frances Chung
  • Jean Wong
Reports of Original Investigations

Abstract

Purpose

Propofol dosing based on total body weight (TBW) can lead to overdosing in morbidly obese (MO) patients. Our aim was to determine whether an induction dose of propofol based on a bispectral index (BIS) target is better for achieving loss of consciousness in MO patients than dosing based on lean body weight (LBW).

Methods

Sixty MO patients with a body mass index (BMI) of ≥ 40 kg·m−2 were randomized to either BIS- or LBW-based propofol dosing groups. Anesthesia was induced with a propofol infusion of 100 mg·kg−1·hr−1 to an initial target endpoint of a BIS of 50 (BIS group) or until a precalculated dose of 2.6 mg·kg−1 LBW based on the Janmahasatian equation was administered (LBW group). Induction was assessed using the observer’s assessment alertness/sedation scale (OAA/S). If an OAA/S score of 0 was not achieved, infusions continued until it reached 0. The groups were compared for the primary outcome which was the difference in the propofol doses at the initial target endpoint.

Results

The median [interquartile range] OAA/S score at the initial target endpoint was lower in the BIS group than in the LBW group (0 [0-0] vs 1 [0-3], respectively; median difference 1, 95% confidence interval [CI] 0 to 3; P = 0.001). The number of patients requiring additional propofol doses was also higher for the LBW group [1 vs 18 patients, respectively; relative risk of requiring additional propofol 18; 95% CI 3 to 126; P = 0.001]. The mean (SD) propofol dose at the target endpoint was significantly lower in the LBW group than in the BIS group [164 (36) mg vs 225 (44) mg, respectively; mean difference 61 mg; 95% CI 41 to 83 mg; P = 0.002]. There was no difference between the two groups, however, regarding the total induction dose of propofol needed for the OAA/S to reach 0 (P = 0.07).

Conclusion

The induction dose of propofol based on the BIS index was different from the induction dose based on LBW in MO patients. Patients in the LBW group required additional propofol to achieve an OAA/S of 0.

Posologie optimale de propofol pour l’induction des patients obèses morbides: une étude randomisée contrôlée comparant l’indice bispectral et une échelle de poids idéal

Résumé

Objectif

Le dosage du propofol en fonction du poids corporel total (PCT) peut entraîner un surdosage chez les patients obèses morbides. Notre objectif était de déterminer si une dose d’induction de propofol fondée sur une cible d’indice bispectral (BIS) était plus adaptée pour obtenir une perte de conscience chez les patients obèses morbides qu’une posologie fondée sur le poids idéal.

Méthode

Soixante patients obèses morbides avec un indice de masse corporel (IMC) ≥ 40 kg·m−2 ont été randomisés en groupes posologiques de propofol fondés sur le BIS ou le poids idéal. L’anesthésie a été induite à l’aide d’une perfusion de propofol de 100 mg·kg−1·h−1 jusqu’à une cible initiale de BIS de 50 (groupe BIS) ou jusqu’à ce qu’une dose pré-calculée de 2,6 mg·kg−1 de poids idéal, fondée sur la formule de Janmahasatian, soit administrée (groupe poids idéal). L’induction a été évaluée selon l’échelle de sédation OAA/S (Observer’s Assessment Alertness/Sedation Scale). Si un score de 0 sur l’échelle OAA/S n’était pas obtenu, les perfusions étaient poursuivies jusqu’à l’obtention de cette valeur. Les groupes ont été comparés par rapport au critère d’évaluation principal, soit la différence entre les doses de propofol au critère d’évaluation initial.

Résultats

Le score OAA/S médian [écart interquartile] au critère d’évaluation initial était plus bas dans le groupe BIS que dans le groupe poids idéal (0 [0-0] vs 1 [0-3], respectivement; différence médiane 1, intervalle de confiance [IC] 95 % 0 à 3; P = 0,001). Le nombre de patients nécessitant des doses supplémentaires de propofol était également plus élevé dans le groupe poids idéal [1 vs 18 patients, respectivement; risque relatif d’avoir besoin de propofol supplémentaire 18; IC 95 % 3 à 126; P = 0,001]. La dose moyenne (ÉT) de propofol au critère d’évaluation initial était significativement plus basse dans le groupe poids idéal que dans le groupe BIS [164 (36) mg vs 225 (44) mg, respectivement; différence moyenne 61 mg; IC 95 % 41 à 83 mg; P = 0,002]. Aucune différence n’a toutefois été observée entre les deux groupes quant à la dose d’induction totale de propofol nécessaire pour que l’échelle OAA/S atteigne 0 (P = 0,07).

Conclusion

La dose d’induction de propofol fondée sur l’indice BIS était différente de celle fondée sur le poids idéal chez les patients obèses morbides. Les patients du groupe poids idéal ont eu besoin de plus de propofol pour atteindre un score de 0 sur l’échelle OAA/S.

References

  1. 1.
    Jarolimova J, Tagoni J, Stern TA. Obesity: its epidemiology, comorbidities, and management. Prim care companion CNS Disord 2013. DOI:10.4088/PCC.12f01475.PubMedPubMedCentralGoogle Scholar
  2. 2.
    Anonymous. Obesity: preventing and managing the global epidemic. Report of a WHO consultation. World Health Organ Tech Rep Ser 2000; 894: i-xii, 1-253.Google Scholar
  3. 3.
    Neligan PJ. Metabolic syndrome: anesthesia for morbid obesity. Curr Opin Anaesthesiol 2010; 23: 375-83.CrossRefPubMedGoogle Scholar
  4. 4.
    Adams TD, Davidson LE, Litwin SE, et al. Health benefits of gastric bypass surgery after 6 years. JAMA 2012; 308: 1122-31.CrossRefPubMedPubMedCentralGoogle Scholar
  5. 5.
    Janmahasatian S, Duffull SB, Ash S, Ward LC, Byrne NM, Green B. Quantification of lean bodyweight. Clin Pharmacokinet 2005; 44: 1051-65.CrossRefPubMedGoogle Scholar
  6. 6.
    Green B, Duffull SB. What is the best size descriptor to use for pharmacokinetic studies in the obese? Br J Clin Pharmacol 2004; 58: 119-33.CrossRefPubMedPubMedCentralGoogle Scholar
  7. 7.
    Morgan DJ, Bray KM. Lean body mass as a predictor of drug dosage. Implications for drug therapy. Clin Pharmacokinet 1994; 26: 292-307.PubMedGoogle Scholar
  8. 8.
    Ingrande J, Brodsky JB, Lemmens HJ. Lean body weight scalar for the anesthetic induction dose of propofol in morbidly obese subjects. Anesth Analg 2011; 113: 57-62.CrossRefPubMedGoogle Scholar
  9. 9.
    Ingrande J, Lemmens HJ. Dose adjustment of anaesthetics in the morbidly obese. Br J Anaesth 2010; 105(Suppl 1): i16-23.CrossRefPubMedGoogle Scholar
  10. 10.
    Salome CM, King GG, Berend N. Physiology of obesity and effects on lung function. J Appl Physiol 1985; 2010(108): 206-11.Google Scholar
  11. 11.
    Duflou J, Virmani R, Rabin I, Burke A, Farb A, Smialek J. Sudden death as a result of heart disease in morbid obesity. Am Heart J 1995; 130: 306-13.CrossRefPubMedGoogle Scholar
  12. 12.
    Drenick EJ, Fisler JS. Sudden cardiac arrest in morbidly obese surgical patients unexplained after autopsy. Am J Surg 1988; 155: 720-6.CrossRefPubMedGoogle Scholar
  13. 13.
    Reeder BA, Senthilselvan A, Despres JP, et al. The association of cardiovascular disease risk factors with abdominal obesity in Canada. Canadian Heart Health Surveys Research Group. CMAJ 1997; 157(Suppl 1): S39-45.PubMedGoogle Scholar
  14. 14.
    Schneider H, Schaub CD, Chen CA, et al. Neural and local effects of hypoxia on cardiovascular responses to obstructive apnea. J Appl Physiol 1985; 2000(88): 1093-102.Google Scholar
  15. 15.
    Meyhoff CS, Henneberg SW, Jorgensen BG, Gatke MR, Rasmussen LS. Depth of anaesthesia monitoring in obese patients: a randomized study of propofol-remifentanil. Acta Anaesthesiol Scand 2009; 53: 369-75.CrossRefPubMedGoogle Scholar
  16. 16.
    Han PY, Duffull SB, Kirkpatrick CM, Green B. Dosing in obesity: a simple solution to a big problem. Clin Pharmacol Ther 2007; 82: 505-8.CrossRefPubMedGoogle Scholar
  17. 17.
    Bonhomme V, Hans P. Monitoring depth of anaesthesia: is it worth the effort? Eur J Anaesthesiol 2004; 21: 423-8.CrossRefPubMedGoogle Scholar
  18. 18.
    Gurses E, Sungurtekin H, Tomatir E, Dogan H. Assessing propofol induction of anesthesia dose using bispectral index analysis. Anesth Analg 2004; 98: 128-31.CrossRefPubMedGoogle Scholar
  19. 19.
    Leykin Y, Miotto L, Pellis T. Pharmacokinetic considerations in the obese. Best Pract Res Clin Anaesthesiol 2011; 25: 27-36.CrossRefPubMedGoogle Scholar
  20. 20.
    Merchant R, Chartrand D, Dain S, et al. Guidelines to the practice of anesthesia - revised edition 2016. Can J Anesth 2016; 63: 86-112.Google Scholar
  21. 21.
    Arya S, Asthana V, Sharma JP. Clinical vs. bispectral index-guided propofol induction of anesthesia: a comparative study. Saudi J Anaesth 2013; 7: 75-9.Google Scholar
  22. 22.
    Chernik DA, Gillings D, Laine H, et al. Validity and reliability of the Observer’s Assessment of Alertness/Sedation Scale: study with intravenous midazolam. J Clin Psychopharmacol 1990; 10: 244-51.CrossRefPubMedGoogle Scholar
  23. 23.
    Gardner MJ, Altman DG. Statisitics with confidence. BMJ publications, 1994.Google Scholar
  24. 24.
    Adams JP, Murphy PG. Obesity in anaesthesia and intensive care. Br J Anaesth 2000; 85: 91-108.CrossRefPubMedGoogle Scholar
  25. 25.
    Cheymol G. Effects of obesity on pharmacokinetics implications for drug therapy. Clin Pharmacokinet 2000; 39: 215-31.CrossRefPubMedGoogle Scholar
  26. 26.
    Avram MJ, Krejcie TC. Using front-end kinetics to optimize target-controlled drug infusions. Anesthesiology 2003; 99: 1078-86.CrossRefPubMedGoogle Scholar
  27. 27.
    La Colla L, Albertin A, La Colla G, et al. No adjustment vs. adjustment formula as input weight for propofol target-controlled infusion in morbidly obese patients. Eur J Anaesthesiol 2009; 26: 362-9.CrossRefPubMedGoogle Scholar
  28. 28.
    van Kralingen S, Diepstraten J, van de Garde EM, et al. Comparative evaluation of propofol 350 and 200 mg for induction of anaesthesia in morbidly obese patients: a randomized double-blind pilot study. Eur J Anaesthesiol 2010; 27: 572-4.PubMedGoogle Scholar
  29. 29.
    Collis T, Devereux RB, Roman MJ, et al. Relations of stroke volume and cardiac output to body composition: the strong heart study. Circulation 2001; 103: 820-5.CrossRefPubMedGoogle Scholar
  30. 30.
    Servin F, Farinotti R, Haberer JP, Desmonts JM. Propofol infusion for maintenance of anesthesia in morbidly obese patients receiving nitrous oxide. A clinical and pharmacokinetic study. Anesthesiology 1993; 78: 657-65.PubMedGoogle Scholar
  31. 31.
    Mitchell SJ, Kirkpatrick CM, Le Couteur DG, et al. Estimation of lean body weight in older community-dwelling men. Br J Clin Pharmacol 2010; 69: 118-27.CrossRefPubMedPubMedCentralGoogle Scholar
  32. 32.
    Friesen JH. Lean-scaled weight: a proposed weight scalar to calculate drug doses for obese patients. Can J Anesth 2013; 60: 214-5.CrossRefPubMedGoogle Scholar
  33. 33.
    Friesen JH. Lean body weight is not a weight scalar for estimating drug doses in morbid obesity. Obes Surg 2015; 25: 1496-7.CrossRefPubMedGoogle Scholar
  34. 34.
    Schneider JH, Küper M, Königsrainer A, Brücher B. Transient lower esophageal sphincter relaxation in morbid obesity. Obes Surg 2009; 19: 595-600.CrossRefPubMedGoogle Scholar
  35. 35.
    Avidan MS, Zhang L, Burnside BA, et al. Anesthesia awareness and the bispectral index. N Engl J Med 2008; 358: 1097-108.CrossRefPubMedGoogle Scholar
  36. 36.
    Nightingale CE, Cousins JM, Fox WT, Kennedy NJ, Margarson MP, Shearer E. Response to NAP5 from the society for obesity and bariatric anaesthesia SOBA. Br J Anaesth 2015; 115: 140-1.CrossRefPubMedGoogle Scholar
  37. 37.
    Ellerkmann RK, Kreuer S, Wilhelm W, Ropcke H, Hoeft A, Bruhn J. Reduction in anaesthetic drug consumption is correlated with mean titrated intra-operative bispectral index values. Acta Anaesthesiol Scand 2006; 50: 1244-9.CrossRefPubMedGoogle Scholar
  38. 38.
    Liu SS. Effects of bispectral index monitoring on ambulatory anesthesia: a meta-analysis of randomized controlled trials and a cost analysis. Anesthesiology 2004; 101: 311-5.CrossRefPubMedGoogle Scholar
  39. 39.
    Punjasawadwong Y, Boonjeungmonkol N, Phongchiewboon A. Bispectral index for improving anaesthetic delivery and postoperative recovery. Cochrane database Syst Rev 2007; 17: CD003843.Google Scholar
  40. 40.
    Pandazi A, Bourlioti A, Kostopanagiotou G. Bispectral index (BIS) monitoring in morbidly obese patients undergoing gastric bypass surgery: experience in 23 patients. Obes Surg 2005; 15: 58-62.CrossRefPubMedGoogle Scholar
  41. 41.
    Glass PS, Bloom M, Kearse L, Rosow C, Sebel P, Manberg P. Bispectral analysis measures sedation and memory effects of propofol, midazolam, isoflurane, and alfentanil in healthy volunteers. Anesthesiology 1997; 86: 836-47.CrossRefPubMedGoogle Scholar
  42. 42.
    Sprung J, Ogletree-Hughes ML, McConnell BK, Zakhary DR, Smolsky SM, Moravec CS. The effects of propofol on the contractility of failing and nonfailing human heart muscles. Anesth Analg 2001; 93: 550-9.CrossRefPubMedGoogle Scholar
  43. 43.
    Iselin-Chaves IA, El Moalem HE, Gan TJ, Ginsberg B, Glass PS. Changes in the auditory evoked potentials and the bispectral index following propofol or propofol and alfentanil. Anesthesiology 2000; 92: 1300-10.CrossRefPubMedGoogle Scholar
  44. 44.
    Morse Z, Kaizu M, Sano K, Kanri T. BIS monitoring during midazolam and midazolam-ketamine conscious intravenous sedation for oral surgery. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002; 94: 420-4.CrossRefPubMedGoogle Scholar
  45. 45.
    Zanner R, Pilge S, Kochs EF, Kreuzer M, Schneider G. Time delay of electroencephalogram index calculation: analysis of cerebral state, bispectral, and Narcotrend indices using perioperatively recorded electroencephalographic signals. Br J Anaesth 2009; 103: 394-9.CrossRefPubMedGoogle Scholar
  46. 46.
    Donaldson M, Goodchild JH. Use of bispectral index system (BIS) to monitor enteral conscious (moderate) sedation during general dental procedures. J Can Dent Assoc 2009; 75: 709.PubMedGoogle Scholar

Copyright information

© Canadian Anesthesiologists' Society 2017

Authors and Affiliations

  • Yamini Subramani
    • 1
  • Waleed Riad
    • 2
  • Frances Chung
    • 1
  • Jean Wong
    • 1
  1. 1.Department of Anesthesia, Toronto Western HospitalUniversity Health NetworkTorontoCanada
  2. 2.Department of AnesthesiaCorniche HospitalAbu DhabiUnited Arab Emirates

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