| 1. |
- Lindholm, Maj-Lis, et al.
(author)
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Cumulated Time With Low Bispectral Index Values Is Not Related to the Risk of New Cancer or Death Within 5 Years After Surgery in Patients With Previous or Prevailing Malignancy
- 2014
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In: Anesthesia and Analgesia. - : Lippincott Williams & Wilkins. - 0003-2999 .- 1526-7598. ; 118:4, s. 782-787
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Journal article (peer-reviewed)abstract
- BACKGROUND: Preclinical data indicate that anesthesia and surgery may promote cancer growth. We previously found no increased risk of malignant disease within 5 years regarding duration of general anesthesia (T-ANESTH) and time with Bispectral Index (BIS) under 45 (T-BIS less than 45) in patients without any diagnosis or history of malignancy before or within 1 month after surgery. Because immunocompetence may be different in patients with previous malignant disease, we investigated the corresponding risk in patients with earlier or existing malignant disease at the time of surgery. METHODS: In a prospective cohort of 766 BIS-monitored patients anesthetized with sevoflurane, new malignant diagnoses and death within 5 years after surgery were retrieved. Cox regression was used to assess the risk of new cancer and all-cause death during follow-up in relation to (T-ANESTH) and (T-BIS less than45). RESULT: Fifty-one patients (6.7%) were assigned 54 new malignant diagnoses within 5 years after surgery. Cancer surgery comprised 387 (51%) of the index operations. Two hundred ninety-three (38 %) of the patients died during follow-up. No relation between T-ANESTH or T-BIS less than45 and new malignant disease (hazard ratio [HR] 0.64-1.11 and 0.76-1.30, respectively) or death was found (HR 0.85-1.05 and 0.94-1.16, respectively). Nor were any corresponding significant relations obtained when other thresholds for BIS (i.e., less than 30, 40, and 50, respectively) were investigated. CONCLUSION: In patients with previous or existing malignant disease, neither duration of anesthesia nor increased cumulative time with profound sevoflurane anesthesia was associated with an increased risk for new cancer or death within 5 years after surgery. Monitoring depth of anesthesia is not expected to alter the risk of cancer proliferation after surgery.
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| 2. |
- Lindholm, Maj-Lis, et al.
(author)
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Mortality Within 2 Years After Surgery in Relation to Low Intraoperative Bispectral Index Values and Preexisting Malignant Disease
- 2009
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In: ANESTHESIA AND ANALGESIA. - : Ovid Technologies (Wolters Kluwer Health). - 0003-2999 .- 1526-7598. ; 108:2, s. 508-512
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Journal article (peer-reviewed)abstract
- BACKGROUND: A correlation between deep anesthesia (defined as time with Bispectral Index (BIS) <45; T-BIS <45 and death within 1. yr after surgery has previously been reported. In order to confirm or refute these findings, we evaluated T-BIS (<45) as an independent risk factor for death within I and 2 yr after surgery and also the impact of malignancy, the predominant cause of death in the previous report. METHODS: Mortality within 2 yr after surgery, causes of death and the occurrence of malignant disease at the time of surgery were identified in a cohort of 4087 BIS-monitored patients. Statistically significant univariate predictors of mortality were identified. In order to allow for comparison with previous data, the following multivariate analysis was first done without, and thereafter with, preexisting malignancy status, the predominant cause of death. RESULTS: One-hundred-seventy-four (4.3%) patients died within I yr and another 92 during the second year (totaling 6.5% in 2 yr). T-BIS <45 was a significant predictor of 1- and 2-yr mortality when preexisting malignant disease was not among the co-variates (hazard ratio [HR] 113 [1.01-1.27] and 1.18 [1.08-1.29], respectively). Further exploration confined the significant relation between postoperative mortality and T-BIS <45 to Patients with preexisting malignant diagnoses associated with extensive Surgery and less favorable prognosis. The most powerful predictors of 2-yr mortality in the model, including preexisting malignancy, were ASA physical score class IV (HR 19.3 [7.31-51.1]), age >80 yr (HR 2.93 [1.79-4.79]), and preexisting malignancy associated with less favorable prognosis (HR 9.30 [6.60-13.1]). When the initial multivariate regression was repeated using preexisting malignancy status among the co-variates in the model, the previously significant relation between 1, and 2-yr mortality and T-BIS <45 did not reach statistical significance. CONCLUSION: Using a similar set of co-variates as in previous work, we confirmed the statistical relation between 1-yr mortality and T-BIS <45, and we extended this observation to 2-yr mortality. However, this relation is sensitive to the selection of co-variates in the statistical model, and a randomized study is required to demonstrate that there really is a causal impact from and T-BIS (<45) on postoperative mortality and, if it does, the effect is probably very weak in comparison with co-morbidity as assessed by ASA physical score, the preexisting malignancy status at surgery and age.
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| 3. |
- Samuelsson, Peter, 1961-, et al.
(author)
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BIS does not predict dreams reported after anaesthesia
- 2008
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In: Acta Anaesthesiologica Scandinavica. - Malden, MA, USA : Wiley-Blackwell. - 0001-5172 .- 1399-6576. ; 52:6, s. 810-814
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Journal article (peer-reviewed)abstract
- Background: In earlier studies, between 1% and 57% of patients have been reported to dream during anaesthesia. Thus, dreaming is much more common than definite memories of real events. We wanted to examine whether dreaming during anaesthesia is related to insufficient hypnotic action, as indicated by BIS levels and, thus, may constitute a risk for awareness.Methods: After IRB approval, 2653 consecutive surgical patients were included. BIS registrations were recorded continuously during the anaesthetic procedure. The patients were interviewed on three occasions after anaesthesia. Standard questions, according to Brice, to evaluate awareness and dreaming during anaesthesia were asked. The dreams were categorized as either pleasant/neutral or unpleasant without any further evaluation of the dream content. Episodes with a mean BIS below 40, above 60 and above 70 were identified and subdivided according to duration (1, 2, 4 and 6 min, respectively). The total time as well as number and duration of episodes for the three BIS-levels were used to analyze any relation to reported dreaming. The mean BIS was also analyzed.Results: Dreaming during anaesthesia was reported by 211 of patients (8.0%) on at least one of the post-operative interviews. BIS data did not show any significant correlation with dreaming, and neither did any of the tested case-specific parameters (gender, age, ASA group, BMI, use of relaxants, induction agent, maintenance agent, length of procedure, omitting N2O and concomitant regional anaesthesia).Conclusion: Dreaming during anaesthesia seems to be a separate phenomenon, not in general related to insufficient anaesthesia as indicated by high BIS levels.
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| 4. |
- Samuelsson, Peter, 1961-, et al.
(author)
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Intraoperative dreams reported after general anaesthesia are not early interpretations of delayed awareness
- 2008
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In: Acta Anaesthesiologica Scandinavica. - Malden, MA United States : Wiley-Blackwell. - 0001-5172 .- 1399-6576. ; 52:6, s. 805-809
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Journal article (peer-reviewed)abstract
- Background: Dreams are more frequently reported than awareness after surgery. We define awareness as explicit recall of real intraoperative events during anaesthesia. The importance of intraoperative dreaming is poorly understood. This study was performed to evaluate whether intraoperative dreams can be associated with, or precede, awareness. We also studied whether dreams can be related to case-specific parameters.Methods: A cohort of 6991 prospectively included patients given inhalational anaesthesia were interviewed for dreams and awareness at three occasions; before they left the post-anaesthesia care unit, days 1–3 and days 7–14 after the operation. Uni- and multivariate statistical relations between dreams, awareness and case-specific parameters were assessed.Results: Two hundred and thirty-two of 6991 patients (3.3%) reported a dream. Four of those also reported awareness and remembered real events that were distinguishable from their dream. Awareness was 19 times more common among patients who after surgery reported a dream [1.7% vs. 0.09%; odds ratio (OR) 18.7; P=0.000007], but memories of dreams did not precede memories of awareness in any of the 232 patients reporting a dream. Unpleasant dreams were significantly more common when thiopentone was used compared with propofol (OR 2.22; P=0.005). Neutral or pleasant dreams were related to lower body mass index, female gender and shorter duration of anaesthesia.Conclusions: We found a statistically significant association between dreams reported after general anaesthesia and awareness, although intraoperative dreams were not an early interpretation of delayed awareness in any case. A typical dreamer in this study is a lean female having a short procedure.
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| 5. |
- Samuelsson, Peter, 1961-, et al.
(author)
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Late Psychological Symptoms after Awareness among Consecutively Included Surgical Patients
- 2007
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In: Anesthesiology. - : Ovid Technologies (Wolters Kluwer Health). - 0003-3022 .- 1528-1175. ; 106:1, s. 26-32
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Journal article (peer-reviewed)abstract
- Background: Awareness during general anesthesia can cause late psychological symptoms. Selection bias may have affected the results in previous retrospective studies. The authors used prospective consecutive collection to recruit patients with previous awareness.Methods: In a cohort of 2,681 consecutive patients scheduled to undergo general anesthesia, 98 considered themselves to have been aware during previous surgery. Six patients died before inclusion, and another 13 were excluded (4 cases of stoke or dementia, 7 declined to participate, and 2 could not be located). Seventy-nine patients were interviewed by telephone, and medical records were checked in uncertain cases. The interview followed a structured protocol, including seven late symptoms (anxiety, chronic fear, nightmares, flashbacks, indifference, loneliness, and lack of confidence in future life). Three persons independently assessed the interviews for classification, to determine whether awareness had occurred.Results: Four cases were performed using regional anesthesia, and another 29 were not considered as awareness by the assessors. Therefore, the final analyses included 46 patients. Twenty (43%) had experienced pain, and 30 (65%) described acute emotional reactions during the awareness episode. Fifteen (33%) patients had experienced late psychological symptoms afterward. In 6 of those cases, the symptoms lasted for more than 2 months, and 1 patient had a diagnosis of post-traumatic stress disorder. Acute emotional reactions were significantly related to late psychological symptoms (P < 0.05).Conclusion: The method for recruiting awareness cases in studies on late psychological symptoms may affect the result. The authors found fewer and milder problems, despite a similar degree of initial problems as in previous studies.
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| 6. |
- Sandin, Rolf H, et al.
(author)
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Awareness during anaesthesia : a prospective case study
- 2000
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In: The Lancet. - : Lancet. - 0140-6736 .- 1474-547X. ; 355:9205, s. 707-711
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Journal article (peer-reviewed)abstract
- BackgroundPatients who are given general anaesthesia are not guaranteed to remain unconscious during surgery. Knowledge about the effectiveness of current protective measures is scarce, as is our understanding of patients' responses to this complication. We did a prospective case study to assess conscious awareness during anaesthesia.Methods11 785 patients who had undergone general anaesthesia were interviewed for awareness on three occasions: before they left the post-anaesthesia care unit, and 1–3 days and 7–14 days after the operation.FindingsWe identified 18 cases of awareness and one case of inadvertent muscle blockade that had occurred before unconsciousness. Incidence of awareness was 0·18% in cases in which neuromuscular blocking drugs were used, and 0·10% in the absence of such drugs. 17 cases of awareness were identified at the final interview, but no more than 11 would have been detected if an interview had been done only when the patients left the post-anaesthesia care unit. Four non-paralysed patients recalled intraoperative events, but none had anxiety during wakefulness or had delayed neurotic symptoms. This finding contrasts with anaesthesia with muscle relaxants, during which 11 of 14 patients had pain, anxiety, or delayed neurotic symptoms. After repeated discussion and information, the delayed neurotic symptoms resolved within 3 weeks in all patients. Analysis of individual cases suggests that a reduced incidence of recall of intraoperative events would not be achieved by monitoring of end-tidal anaesthetic gas concentration or by more frequent use of benzodiazepines.InterpretationThe inability to prevent awareness by conventional measures may advocate monitoring of cerebral activity by neurophysiological techniques. However, the sensitivity of such techniques is not known, and in the light of our findings, at least 861 patients would need to be monitored to avoid one patient from suffering due to awareness during relaxant anaesthesia.
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