Long-term psychosocial outcomes after intraoperative awareness with recall.

BACKGROUND: Posttraumatic stress disorder, a common psychiatric disorder in the general population, may follow a traumatic experience of awareness with recall during general anesthesia. METHODS: We conducted a matched cohort design with 9 subjects after intraoperative awareness with recall during general anesthesia. A psychiatric diagnostic interview and questionnaire were performed on 9 matched controls and 9 subjects, a median of 17.2 years from their documented awareness episode. The subjects and the matched controls completed a battery of questionnaires related to psychosocial well-being, after which they participated in a diagnostic Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Axis I Disorders. RESULTS: Patients with awareness did not seem to differ from their matched controls in subsequent psychosocial outcome, psychiatric morbidity, or quality of life. CONCLUSIONS: We found no indication that intraoperative awareness with recall had any deleterious long-term effects on patients' psychosocial outcome.

Spectral entropy as a measure of hypnosis in children.

BACKGROUND: The Datex-Ohmeda S/5 Entropy Module (Datex-Ohmeda Division, Instrumentarium Corp., Helsinki, Finland), using time-frequency balanced Spectral Entropy, is a novel tool for monitoring the hypnotic state during anesthesia. The Entropy Module produces two values, State Entropy (SE) and Response Entropy (RE), and in adults, it has been shown to measure reliably the hypnotic effects of various drugs. In children, Spectral Entropy has been only preliminary studied. The authors' aim was to study Spectral Entropy as a marker of hypnotic state during general anesthesia in infants and children. METHODS: Twenty infants (aged 1 month-1 yr) and 40 children (aged 1-15 yr) were anesthetized for surgery using standardized sevoflurane-nitrous oxide-based anesthesia. The relationships between SE, RE, or Bispectral Index (BIS) and (1) a modified Observer's Assessment of Alertness/Sedation Scale, (2) non-steady state end-tidal concentration of sevoflurane, (3) steady state end-tidal concentration of sevoflurane, and (4) hemodynamic values were calculated using prediction probability, nonlinear regression, and correlation coefficients, as appropriate. The performances of SE, RE, and BIS were compared. RESULTS: The prediction probability values (+/- SEM) of SE, RE, and BIS versus the modified Observer's Assessment of Alertness/Sedation Scale in the induction phase were 0.83 +/- 0.06, 0.88 +/- 0.06, and 0.87 +/- 0.08 for children and 0.76 +/- 0.08,0.79 +/- 0.08, and 0.73 +/- 0.10 for infants; values in the emergence phase were 0.68 +/- 0.05, 0.74 +/- 0.04, and 0.64 +/- 0.05 for children and 0.64 +/- 0.07, 0.69 +/- 0.06, and 0.72 +/- 0.06 for infants, respectively. SE, RE, and BIS values were inversely proportionally related to the end-tidal concentration of sevoflurane for children, but for infants, the correlation was much less clear. No significant correlations were found between SE, RE, or BIS values and the hemodynamic values. CONCLUSIONS: Spectral Entropy may be a useful tool for measuring the level of hypnosis in anesthetized children and seems to perform as well as BIS. In infants, the clinical usefulness of both these electroencephalogram-derived methods must be evaluated in further controlled studies.

Hemodynamic effects of rescue protocol hydrocortisone in neonates with low cardiac output syndrome after cardiac surgery.

OBJECTIVE: To assess the hemodynamic effects and safety of hydrocortisone in neonates with low cardiac output syndrome requiring high levels of inotropic support and fluid resuscitation after cardiac surgery. DESIGN: Retrospective chart review. SETTING: Fifteen-bed pediatric cardiovascular intensive care unit. PATIENTS: Twelve neonates with low cardiac output syndrome after cardiac surgery to whom hydrocortisone was administered according to one of two dosing regimens (100 mg/[m.day] for 2 days, 50 mg/[m.day] for 2 days, and 25 mg/[m.day] for 1 day or 100 mg/[m.day] for 1 day, 50 mg/[m.day] for 2 days, and 25 mg/[m.day] for 2 days) were identified from the Department of Pharmacy database between September 2002 and January 2004. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The mean and systolic blood pressure increased significantly 3 hrs after hydrocortisone treatment from the values preceding hydrocortisone administration. The mean blood pressure increased from 44.0+/-3.0 to 55.4+/-2.3 mm Hg (p=.01) and the systolic blood pressure increased from 64.2+/-4.7 to 78.3+/-3.4 mm Hg (p=.04). Comparable beneficial changes were also seen in the heart rate, which decreased from 168.3+/-4.6 to 148.3+/-5.6 beats/min (p=.004) after 24 hrs of hydrocortisone administration and remained at this level during the 72 hrs of follow-up. Significant weaning of epinephrine infusions was possible, from a mean dose of 0.16 to 0.06 microg/(kg.min) (p=.008), within 24 hrs after the initiation of steroid administration, and this reduction was not offset by increases in other inotropic agents. hydrocortisone administration caused nonsignificant increases in mean blood glucose concentration (from 116.2+/-20.6 to 156.0+/-25.6 mg/dL; p=.64), mean white blood cell count (from 16.6+/-1.6 to 18.9+/-2.6 x 10 U/L; p=.35), and sodium level (from 144.7+/-1.3 to 145.3+/-1.3 mmol/L; p=.51). Ten of the 12 patients (83.3%) survived. CONCLUSION: Most of the hemodynamically compromised neonates who were unresponsive to high doses of inotropic agents and fluid resuscitation after heart surgery responded to hydrocortisone with improvement of hemodynamic parameters and a decrease in inotropic requirements.

Patients' conscious recollections from cardiac anesthesia.

OBJECTIVE: To estimate the current incidence of conscious recollections from the time of anesthesia, the contribution of anesthetic drugs to this incidence, and the patients' experience of cardiac anesthesia and surgery. DESIGN: Prospective, horizontal survey of cardiac surgery patients using structured interview method. SETTING: Tertiary care university hospital. PARTICIPANTS: All cardiac surgery patients during 1 year (n = 1,218). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 1,218 patients operated on, 929 were interviewed. The patients' memories were classified to estimate the number of patients with possible or definite intraoperative awareness and later conscious recall. The use of anesthetics was estimated from anesthetic charts for patients with awareness and recall and control patients. These charts were compared using Poisson regression. The incidence of definite awareness with recall was 0.5% (5 patients), and the incidence of possible recall was 2.3% (21 patients). A lower dose of midazolam was used for the patients with awareness and recall. Only 1 patient rated the experience of awareness as the worst perioperative memory. Benzodiazepine premedication caused amnesia for the preoperative period but not for the time of anesthesia. CONCLUSION: The incidence of awareness and recall is similar to the incidence reported during general surgery. Cardiac surgery does not carry increased risk of awareness. Benzodiazepines given during anesthesia are effective in decreasing the incidence of recalled awareness, and the experience of awareness is not often particularly traumatizing. Premedication with benzodiazepine is not effective in preventing recollection of anesthesia, however.

Application of artificial neural networks as an indicator of awareness with recall during general anaesthesia.

OBJECTIVE: Awareness with recall is a rare but serious complication of general anaesthesia with an incidence ranging from 0.1%-0.7%. In the absence of a reliable depth-of-anaesthesia monitor, attempts have been made to predict awareness from intraoperative haemodynamic monitoring data, with little success. Artificial neural networks can sometimes detect relationships between input and output variables even when conventional methods fail. Therefore, we subjected standard intraoperative monitoring data to both artificial neural models and conventional statistical methods in an attempt to predict awareness with recall. METHODS: Anaesthesia records from 33 patients with awareness and 510 patients without awareness were collected. Summary data (mean, maximum, and minimum) of end-tidal carbon dioxide concentration, arterial blood oxygen saturation, systolic and diastolic blood pressure, and heart rate were calculated for each patient. These data were subjected to an analysis by artificial neural networks and by Poisson regression. RESULTS: The two best neural models both had sensitivity and specificity of 23% and 98%, respectively. The models have high specificity, and in view of the low incidence of awareness, a high negative predictive value. The prediction probabilities P(k) (SE) for the best neural models were 0.66 (0.08) and 0.60 (0.10), respectively. In the Poisson regression, there were significant differences in systolic and diastolic blood pressures and heart rate between patients with and without awareness. CONCLUSIONS: A prediction indicating awareness by the network is very suggestive of true awareness and recall. Blood pressure and heart rate are significantly higher on average in patients with awareness than in patients without. In an individual patient, however, none of our artificial neural models can detect awareness sufficiently reliably.

Awareness and recall in outpatient anesthesia.

UNLABELLED: We studied the incidence of awareness and explicit recall during general anesthesia in outpatients versus inpatients undergoing surgery. During a 14.5-mo period, we structurally interviewed 1500 outpatients and 2343 inpatients. Among outpatients, there were five cases of awareness and recall (one with clear intraoperative recollections and four with doubtful intraoperative recollections). Of the inpatients, six reported awareness and recall (three with clear and three with doubtful intraoperative recollections). The incidence of clear intraoperative recollections was 0.07% in outpatients and 0.13% in inpatients. The difference in the incidence was not significant. Among outpatients, those with awareness and recall were given smaller doses of sevoflurane than those without awareness and recall (P < 0.05). In conclusion, awareness and recall are rare complications of general anesthesia, and outpatients are not at increased risk for this event compared with inpatients undergoing general anesthesia. IMPLICATIONS: Rapid recovery from general anesthesia is a crucial element of outpatient surgery. However, this practice may predispose a patient to receive less anesthetic, with increased risk for awareness and recall. We have shown that outpatients undergoing an operation using general anesthesia are not at increased risk for awareness compared with inpatients.