Abstract
Objective
To investigate the relationship between memory and intensive care sedation.
Design and setting
Prospective cohort study over 18 months in two general intensive care units (ICUs) in district university hospitals.
Patients
313 intubated mechanically ventilated adults admitted for more than 24 h, 250 of whom completed the study.
Measurements
Patients (n = 250) were interviewed in the ward 5 days after discharge from the ICU using the ICU Memory Tool. Patient characteristics, doses of sedative and analgesic agents, and sedation scores as measured by the Motor Activity Assessment Scale (MAAS) were collected from hospital records after the interview.
Results
Patients with no recall (18%) were significantly older, had higher baseline severity of illness, and experienced fewer periods of wakefulness (median proportion of MAAS score 3; 0.37 vs. 0.70) than those who had memories of the ICU (82%). Multivariate analyses showed that increasing proportion of MAAS 0–2 and older age were significantly associated with having no recall. Patients with delusional memories (34%) had significantly longer ICU stay (median 6.6 vs. 2.2 days), higher baseline severity of illness, higher proportions of MAAS scores 4–6, and more administration of midazolam than those with recall of the ICU without delusional memories.
Conclusions
Heavy sedation increases the risk of having no recall, and longer ICU stay increases the risk of delusional memories. The depth of sedation during total ICU stay as recorded with the MAAS may predict the probability of having memories of the ICU.
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References
Capuzzo M, Valpondi V, Cingolani E, De Luca S, Gianstefani G, Grassi L, Alvisi R (2004) Application of the Italian version of the intensive care unit Memory tool in the clinical setting. Crit Care 8:R48–R55
Leur JP van de, van der Schans CP, Loef BG, Deelman BG, Geertzen JH, Zwaveling JH (2004) Discomfort and factual recollection in intensive care unit patients. Crit Care 8:R467–R473
Griffiths RD, Jones C (2001) Filling the intensive care memory gap? Intensive Care Med 27:344–346
Jones C (2002) Acute psychological problems. In: Griffiths RD, Jones C (ed) Intensive care aftercare. Butterworth-Heinemann, Oxford, pp 19–26
Skirrow P (2002) Delusional memories of ICU. In: Griffiths RD, Jones C (ed) Intensive care aftercare. Butterworth-Heinemann, Oxford, pp 28–35
Hupcey JE, Zimmerman HE (2000) The need to know: experiences of critically ill patients. Am J Crit Care 9:192–198
Jones C, Griffiths RD, Humphris G, Skirrow PM (2001) Memory, delusions, and the development of acute posttraumatic stress disorder-related symptoms after intensive care. Crit Care Med 29:573–580
Rattray J, Johnston M, Wildsmith JA (2005) Predictors of emotional outcomes of intensive care. Anaesthesia 60:1085–1092
Schelling G, Stoll C, Haller M, Briegel J, Manert W, Hummel T, Lenhart A, Heyduck M, Polasek J, Meier M, Preuss U, Bullinger M, Schuffel W, Peter K (1998) Health-related quality of life and posttraumatic stress disorder in survivors of the acute respiratory distress syndrome. Crit Care Med 26:651–659
Granja C, Lopes A, Moreira S, Dias C, Costa-Pereira A, Carneiro A (2005) Patients' recollections of experiences in the intensive care unit may affect their quality of life. Crit Care 9:R96–R109
Hough CL, Curtis JR (2005) Long-term sequelae of critical illness: memories and health-related quality of life. Crit Care 9:145–146
Rotondi AJ, Chelluri L, Sirio C, Mendelsohn A, Schulz R, Belle S, Im K, Donahoe M, Pinsky MR (2002) Patients' recollections of stressful experiences while receiving prolonged mechanical ventilation in an intensive care unit. Crit Care Med 30:746–752
Burchardi H (2004) Aims of sedation/analgesia. Minerva Anestesiol 70:137–143
Walder B, Tramer MR (2004) Analgesia and sedation in critically ill patients. Swiss Med Wkly 134:333–346
Jones C, Griffiths RD, Humphris G (2000) Disturbed memory and amnesia related to intensive care. Memory 8:79–94
McGaugh JL, Cahill L (1997) Interaction of neuromodulatory systems in modulating memory storage. Behav Brain Res 83:31–38
Kolk BA van der (1996) Trauma and memory. In: McFarlane AC, van der Kolk BA, Weisaeth L (ed) Traumatic stress: the effects of overwhelming experience on mind, body, and society. Guilford, New York, pp 279–302
Wagner BK, O'Hara DA, Hammond JS (1997) Drugs for amnesia in the ICU. Am J Crit Care 6:192–201
Clifford JO, Buchman TG (2002) Sedation modulates recognition of novel stimuli and adaptation to regular stimuli in critically ill adults. Crit Care Med 30:609–616
Veselis RA, Reinsel RA, Feshchenko VA, Johnson R (2004) Information loss over time defines the memory defect of propofol: a comparative response with thiopental and dexmedetomidine. Anesthesiology 101:831–841
Capuzzo M, Pinamonti A, Cingolani E, Grassi L, Bianconi M, Contu P, Gritti G, Alvisi R (2001) Analgesia, sedation, and memory of intensive care. J Crit Care 16:83–89
Rundshagen I, Schnabel K, Wegner C, Schulte am Esch S (2002) Incidence of recall, nightmares, and hallucinations during analgosedation in intensive care. Intensive Care Med 28:38–43
Young C, Knudsen N, Hilton A, Reves JG (2000) Sedation in the intensive care unit. Crit Care Med 28:854–866
Samuelson KA, Lundberg D, Fridlund B (2005) Memory in relation to intensive care sedation. Intensive Care Med 31 [Suppl 1]:S12
Brook AD, Ahrens TS, Schaiff R, Prentice D, Sherman G, Shannon W, Kollef MH (1999) Effect of a nursing-implemented sedation protocol on the duration of mechanical ventilation. Crit Care Med 27:2609–2615
Kress JP, Pohlman AS, O'Connor MF, Hall JB (2000) Daily interruption of sedative infusions in critically ill patients undergoing mechanical ventilation. N Engl J Med 342:1471–1477
Knaus WA, Draper EA, Wagner DP, Zimmerman JE (1985) APACHE II: a severity of disease classification system. Crit Care Med 13:818–829
Devlin JW, Boleski G, Mlynarek M, Nerenz DR, Peterson E, Jankowski M, Horst HM, Zarowitz BJ (1999) Motor Activity Assessment Scale: a valid and reliable sedation scale for use with mechanically ventilated patients in an adult surgical intensive care unit. Crit Care Med 27:1271–1275
Jones C, Humphris G, Griffiths R (2000) Preliminary validation of the ICUM tool: a tool for assessing memory of the intensive care experience. Clin Intensive Care 11:251–255
Ely EW, Inouye SK, Bernard GR, Gordon S, Francis J, May L, Truman B, Speroff T, Gautam S, Margolin R, Hart RP, Dittus R (2001) Delirium in mechanically ventilated patients: validity and reliability of the Confusion Assessment Method for the intensive care unit (CAM-ICU). JAMA 286:2703–2710
Altman DG (1991) Practical statistics for medical research. Chapman and Hall, London
Hosmer DW, Lemeshow S (2000) Applied logistic regression. Wiley, New York
Russell S (1999) An exploratory study of patients' perceptions, memories and experiences of an intensive care unit. J Adv Nurs 29:783–791
Bion JF, Logan BK, Newman PM, Brodie MJ, Oliver JS, Aitchison TC, Ledingham IM (1986) Sedation in intensive care: morphine and renal function. Intensive Care Med 12:359–365
Devlin JW, Fraser GL, Kanji S, Riker RR (2001) Sedation assessment in critically ill adults. Ann Pharmacother 35:1624–1632
Jacobi J, Fraser GL, Coursin DB, Riker RR, Fontaine D, Wittbrodt ET, Chalfin DB, Masica MF, Bjerke HS, Coplin WM, Crippen DW, Fuchs BD, Kelleher RM, Marik PE, Nasraway SA, Murray MJ, Peruzzi WT, Lumb PD (2002) Clinical practice guidelines for the sustained use of sedatives and analgesics in the critically ill adult. Crit Care Med 30:119–141
Watson BD, Kane-Gill SL (2004) Sedation assessment in critically ill adults: 2001–2004 update. Ann Pharmacother 38:1898–1906
Roberts B, Chaboyer W (2004) Patients' dreams and unreal experiences following intensive care unit admission. Nurs Crit Care 9:173–180
Kollef MH, Levy NT, Ahrens TS, Schaiff R, Prentice D, Sherman G (1998) The use of continuous i.v. sedation is associated with prolongation of mechanical ventilation. Chest 114:541–548
Cammarano WB, Pittet JF, Weitz S, Schlobohm RM, Marks JD (1998) Acute withdrawal syndrome related to the administration of analgesic and sedative medications in adult intensive care unit patients. Crit Care Med 26:676–684
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Samuelson, K., Lundberg, D. & Fridlund, B. Memory in relation to depth of sedation in adult mechanically ventilated intensive care patients. Intensive Care Med 32, 660–667 (2006). https://doi.org/10.1007/s00134-006-0105-x
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DOI: https://doi.org/10.1007/s00134-006-0105-x