Uptime as a measure of recovery in children postappendectomy

Purpose: The aim of this study was to objectively measure recovery time after open and laparoscopic appendectomy using an activity monitor (PAL 1).Methods: The PAL 1 records the amount of time that the subject is upright (uptime). Children wore the PAL 1 for 10 days continuously, beginning within the first 48 hours postoperatively.Results: Uptime data were collected for 5 or more days for 42 children (open, n = 16; laparoscopic, n = 26). All children had low levels of uptime in the initial postoperative period. There was weak evidence of a quicker recovery rate for children in the laparoscopic group (P = .09). The difference in mean uptime between groups was of statistical significance by day 7 postoperatively with children in the laparoscopic group having a higher mean uptime than those in the open group (difference of 0.7 hours; 95% confidence intervals 0.0 to 1.4 hours in a 24-hour period).Conclusions: The results of this study show that recovery postappendectomy can be quantified by the measurement of uptime and that children undergoing a laparoscopic procedure may recover marginally more quickly than those undergoing an open procedure.     

Spectral entropy as an electroencephalographic measure of anesthetic drug effect: a comparison with bispectral index and processed midlatency auditory evoked response

BACKGROUND: The authors compared the behavior of two calculations of electroencephalographic spectral entropy, state entropy (SE) and response entropy (RE), with the A-Line ARX Index (AAI) and the Bispectral Index (BIS) and as measures of anesthetic drug effect. They compared the measures for baseline variability, burst suppression, and prediction probability. They also developed pharmacodynamic models relating SE, RE, AAI, and BIS to the calculated propofol effect-site concentration (Ceprop). METHODS: With institutional review board approval, the authors studied 10 patients. All patients received 50 mg/min propofol until either burst suppression greater than 80% or mean arterial pressure less than 50 mmHg was observed. SE, RE, AAI, and BIS were continuously recorded. Ceprop was calculated from the propofol infusion profile. Baseline variability, prediction of burst suppression, prediction probability, and Spearman rank correlation were calculated for SE, RE, AAI, and BIS. The relations between Ceprop and the electroencephalographic measures of drug effect were estimated using nonlinear mixed effect modeling. RESULTS: Baseline variability was lowest when using SE and RE. Burst suppression was most accurately detected by spectral entropy. Prediction probability and individualized Spearman rank correlation were highest for BIS and lowest for SE. Nonlinear mixed effect modeling generated reasonable models relating all four measures to Ceprop. CONCLUSIONS: Compared with BIS and AAI, both SE and RE seem to be useful electroencephalographic measures of anesthetic drug effect, with low baseline variability and accurate burst suppression prediction. The ability of the measures to predict Ceprop was best for BIS.     

Spectral entropy monitoring allowed lower sevoflurane concentration and faster recovery in children

Background: Anesthetic titration using spectral entropy monitoring reduces anesthetic requirements and shortens recovery in adult surgical patients. This study was performed to evaluate the effect of entropy monitoring on end‐tidal sevoflurane concentration and recovery characteristics in pediatric patients undergoing sevoflurane anesthesia. Methods: Seventy‐eight children (aged 3–12 years) scheduled for a tonsillectomy and/or an adenoidectomy were randomly divided into one of two groups: standard practice (Standard) or entropy‐guided (Entropy). In the Standard group, sevoflurane was adjusted to maintain the heart rate and systolic blood pressure (BP) within 20% of the baseline values. In the Entropy group, sevoflurane was adjusted to achieve a state entropy of 40–50. We compared the entropy values, end‐tidal sevoflurane concentration and recovery times between groups. Results: During maintenance of anesthesia, the entropy and BP values were higher in the Entropy group (P<0.05). The end‐tidal sevoflurane concentration during maintenance was lower in the Entropy group (2.2 (0.3) vol%) compared with the Standard group (2.6 (0.4) vol%) (P<0.05). Recovery times were faster in the Entropy group (P<0.05). Conclusions: Compared with standard practice, we found that entropy‐guided anesthetic administration was associated with a reduced sevoflurane concentration and a slightly faster emergence and recovery in 3–12‐year‐old children.     

Can state or response entropy be used as a measure of sleep depth?

Summary In this prospective observational study we examined the potential of the spectral entropy measures ‘state’ and ‘response’ entropy (Entropy? monitor), as measures of sleep depth in 12 healthy adult subjects. Both median state and response entropy values varied significantly with sleep stage (p = 0.017 and p = 0.014 respectively; ANOVA). Median state or response entropy did not decrease significantly during the transition from awake to stage I sleep (p > 0.017). State entropy values decreased significantly between sleep stages I and II (p < 0.001). Both state and response entropy values were significantly less (40 and 45 arbitrary units respectively) in stage III (slow wave sleep) vs stage II sleep (p = 0.008). We conclude that state and response entropy values, when expressed as a function of time, may be a useful means of quantifying aspects of sleep.     

Spectral entropy and bispectral index as measures of the electroencephalographic effects of sevoflurane

BACKGROUND: Recently, entropy algorithms have been proposed as electroencephalographic measures of anesthetic drug effects. Datex-Ohmeda (Helsinki, Finland) introduced the Entropy Module, a new electroencephalographic monitor designed for measuring depth of anesthesia. The monitor calculates a state entropy (SE) computed over the frequency range of 0.8-32 Hz and a response entropy (RE) computed over the frequency range of 0.8-47 Hz. The authors investigated the dose-response relation of SE and RE during sevoflurane anesthesia in comparison with the Bispectral Index (BIS). METHODS: Sixteen patients were studied without surgical stimulus. Anesthesia was induced by sevoflurane inhalation with a tight-fitting facemask. Sevoflurane concentrations were increased and subsequently decreased and increased two to four times until the measurement was stopped and patients were intubated for surgery. The performances of SE, RE, and BIS to predict the estimated sevoflurane effect site concentration, obtained by simultaneous pharmacokinetic and pharmacodynamic modeling, were compared by calculating the correlation coefficients and the prediction probability. RESULTS: State entropy, RE, and BIS values decreased continuously over the observed concentration range of sevoflurane. Correlation coefficients were slightly but not significantly better for entropy parameters (0.87 +/- 0.09 and 0.86 +/- 0.10 for SE and RE, respectively) than for BIS (0.85 +/- 0.12). Calculating the prediction probability confirmed these results with a prediction probability of 0.84 +/- 0.05 and 0.82 +/- 0.06 for SE and RE, respectively, and 0.80 +/- 0.06 for BIS. CONCLUSION: State entropy and RE seem to be useful electroencephalographic measures of sevoflurane drug effect.     

Spectral entropy and bispectral index as measures of the electroencephalographic effects of propofol

Recently, Datex-Ohmeda introduced the Entropy Moduletrade mark for measuring depth of anesthesia. Based on the Shannon entropy of the electroencephalogram, state entropy (SE) and response entropy (RE) are computed. We investigated the dose-response relationship of SE and RE during propofol anesthesia in comparison with the Bispectral Indextrade mark (BIS). Twenty patients were studied without surgical stimulus. Anesthesia was induced by a constant propofol infusion of 2000 mg/h (451 +/- 77 microg x min(-1) x kg(-1)) via a large forearm vein. Propofol was infused until substantial burst suppression occurred (more than 50%) or mean arterial blood pressure decreased to <60 mm Hg. Hereafter, infusions were stopped until recovery of BIS values up to 60 was reached. Subsequently, the constant propofol infusion of 2000 mg/h was restarted to increase depth of anesthesia and again decreased (infusion was stopped) within the BIS value range of 40-60. The coefficient of determination (R2) and the prediction probability (P(K)) were calculated to evaluate the performance of SE, RE, and BIS to predict changing propofol effect-site concentrations. R2 values for SE, RE, and BIS of 0.88 +/- 0.08, 0.89 +/- 0.07, and 0.92 +/- 0.06, respectively, were similar. The calculated P(K) values, however, revealed a significant difference between SE and RE compared with BIS, with P(K) = 0.77 +/- 0.09, 0.76 +/- 0.10, and 0.84 +/- 0.06, respectively. BIS seems to show slight advantages in predicting propofol effect-site concentrations compared with SE and RE, as measured by P(K) but not as measured by R2.     

Premedication in children: hypnosis versus midazolam

BACKGROUND: The main objectives of premedication in children are to facilitate the separation from the parents, to reduce preoperative anxiety, to smooth the induction of anesthesia and to lower the risk of postoperative behavioral disorders. The most common technique is sedative premedication with midazolam. Hypnosis enables a state of relaxation to be achieved and has never been evaluated as a premedication technique. The aim of the present study was to evaluate the efficacy of hypnosis on anxiety and perioperative behavioral disorders versus midazolam. METHODS: Fifty children from 2 to 11 years of age were randomized into two groups: group H received hypnosis as premedication; group M were given 0.5 mg x kg(-1) midazolam orally, 30 min before surgery. Preoperative anxiety was evaluated using the Modified Yale Preoperative Anxiety Scale (mYPAS) score when arriving in the department (T1), when entering the operating room (T2), and when fitting the facemask (T3). Postoperative behavioral disorders were evaluated using the Posthospitalization Behavioral Questionnaire (PHBQ) at days 1, 7 and 14. RESULTS: The two groups showed no significant difference preoperatively with the PHBQ: (M) 21 (17-25) vs (H) 20 (8-25) and mYPAS score: (M) 28 (23-75) vs (H) 23 (23-78). The number of anxious children was less during induction of anesthesia in the hypnosis group (T3: 39% vs 68%) (P < 0.05). Postoperatively, hypnosis reduced the frequency of behavior disorders approximately by half on day 1 (30% vs 62%) and day 7 (26% vs 59%). CONCLUSIONS: Hypnosis seems effective as premedication in children scheduled for surgery. It alleviates preoperative anxiety, especially during induction of anesthesia and reduces behavioral disorders during the first postoperative week.     

异丙酚靶控输注期间熵指数对不同年龄患者麻醉深度的预测效果

目的评价异丙酚靶控输注(TCI)期间熵指数对意识状态变化的预测效果及年龄因素对其的影响。方法 ASA Ⅰ或Ⅱ级腹部手患者29例,分为成年组和老年组,采用异丙酚效应室(Ce) 靶浓度分阶段实施TCI,清醒镇静(OAA/S)评分评价意识状态变化,当Ce达到6．0μg·ml-1后气管插管,记录给药前即刻(基础值)达到各靶浓度阶段,气管插管前、插管后即刻和气管插管后1、2、3、4、5、 10min反应熵(RE)、状态熵(SE)、血压、心率、脉搏血氧饱和度。通过预测概率评价熵指数对意识状态的预测效果。结果随着异丙酚Ce增加,RE和SE逐渐降低,RE和SE数值间差距缩小。与基础值比较,成年组Ce 2．0μg·ml-1时,RE和SE降低(P<0．01),老年组Ce 1．5μg·ml-1时,RE降低(P< 0．01),Ce 2．0μg·ml-1时SE降低(P<0．01)。患者意识消失时Ce:成年组(2．0±0．5)μg·ml-1,老年组 (1．4±0．4)μg·ml-1。RE和SE对于意识消失的预测概率分别是成年组:0．774和0．779,老年组:0．735 和0．725。当Ce达到3．0μg·ml-1以上,老年组RE和SE高于成年组(P<0．01),TCI期间两组心率和脉搏血氧饱和度无明显改变。与基础值比较,老年组Ce 2．5μg·ml-1和成年组Ce 3．0μg·ml-1时,血压降低(P<0．01)。气管插管即刻两组RE均轻度升高。结论异丙酚TCI期间,熵指数能预测意识状态的变化,且对成年患者和老年患者的预测效果相当。RE对于意识状态变化的反应更为敏感。     

Approximate entropy as an electroencephalographic measure of anesthetic drug effect during desflurane anesthesia

BACKGROUND: The authors hypothesized that the electroencephalogram (EEG) during higher anesthetic concentrations would show more "order" and less "randomness" than at lower anesthetic concentrations. "Approximate entropy" is a new statistical parameter derived from the Kolmogorov-Sinai entropy formula which quantifies the amount of regularity in data. The approximate entropy quantifies the predictability of subsequent amplitude values of the EEG based on the knowledge of the previous amplitude values. The authors investigated the dose-response relation of the EEG approximate entropy during desflurane anesthesia in comparison with spectral edge frequency 95, median frequency, and bispectral index. METHODS: Twelve female patients were studied during gynecologic laparotomies. Between opening and closure of the peritoneum, end-tidal desflurane concentrations were varied between 0.5 and 1.6 minimum alveolar concentration (MAC). The EEG approximate entropy, median EEG frequency, spectral edge frequency 95, and bispectral index were determined and the performance of each to predict the desflurane effect compartment concentration, obtained by simultaneous pharmacokinetic-pharmacodynamic modeling, was compared. RESULTS: Electroencephalogram approximate entropy decreased continuously over the observed concentration range of desflurane. The performance of the approximate entropy (prediction probability PK = 0.86 +/- 0.06) as an indicator for desflurane concentrations is similar to spectral edge frequency 95 (PK = 0.86 +/- 0.06) and bispectral index (PK = 0.82 +/- 0.06) and is statistically significantly better than median frequency (PK = 0.78 +/- 0.06). CONCLUSIONS: The amount of regularity in the EEG increases with increasing desflurane concentrations. The approximate entropy could be a useful EEG measure of anesthetic drug effect.     

熵指数监测全麻患者镇静水平的准确性

目的 评价反应熵和状态熵监测全麻患者镇静水平的准确性.方法 择期行腹部手术患者20例,ASAⅠ或Ⅱ级,入室后监测反应熵(RE)、状态熵(SE)及脑电双频谱指数(BIS),静脉注射异丙酚、维库溴铵和芬太尼麻醉诱导,气管插管后机械通气,吸入七氟烷、间断静脉注射维库溴铵和芬太尼维持麻醉.分别于入室时、意识消失前10min、意识消失即刻、气管插管时、手术1 h、意识恢复前10 min、意识恢复即刻、拔管后10 min时记录RE、SE和BIS.结果 RE、SE和BIS在意识改变前后差异均有统计学意义(P＜0.05),RE、SE和BIS判断意识消失的临界值分别为76、73和68,灵敏度分别为94%、95%和92%,特异度分别为92%、94%和9l%,临界值判断意识消失的准确度分别为93%、95%、94%;判断意识恢复的临界值分别为82、75和70,灵敏度分别为95%、95%和91%,特异度分别为93%、96%和93%,临界值判断意识恢复的准确度分别为98%、96%和97%.结论 熵指数能够准确地监测全麻患者镇静水平.     

Multiple breath inert gas washout as a measure of ventilation distribution in children with cystic fibrosis

BACKGROUND: Multiple breath inert gas washout (MBW) has been suggested as a tool for detecting early cystic fibrosis (CF) lung disease. A study was undertaken to compare the relative sensitivity of MBW and spirometry for detecting abnormal lung function in school age children with CF and to compare MBW results obtained from healthy children in the UK with those recently reported from Sweden. METHODS: Forced expiratory volume in 1 second (FEV1) and maximal expiratory flow when 25% of forced vital capacity remains to be expired (MEF25) were compared with the lung clearance index (LCI) derived from sulphur hexafluoride MBW in 22 children with CF aged 6-16 years and in 33 healthy controls. RESULTS: LCI was higher in children with CF than in healthy controls (mean difference 5.1 (95% CI of difference 4.1 to 6.1) and FEV1 and MEF25 z-scores were lower (mean difference -2.3 (95% CI -2.9 to -1.7) and -1.8 (95% CI -2.4 to -1.3), respectively; p<0.001 for all). There was a significant negative correlation between LCI and FEV1 (r2 = 0.62) and MEF25 (r2 = 0.46). However, while normal (> or =-1.96 z-scores) FEV1 and MEF25 results were seen in 11 (50%) and 12 (53%) children with CF, respectively, all but one of these children had an abnormally increased LCI. LCI was repeatable in both groups (within subject CV for three measurements 6% for CF and 5% for healthy children). In healthy subjects LCI was independent of age and virtually identical in the British and Swedish children (mean difference 0.1 (95% CI -0.1 to 0.4), p = 0.38) CONCLUSIONS: MBW is reproducible between laboratories, generates normal ranges which are constant over childhood, and is more frequently abnormal than spirometry in children with CF.     

Novel intravenous C-methionine breath test as a measure of liver function in children with short bowel syndrome

Monitoring hepatic function in children with short bowel syndrome (SBS) and parenteral nutrition-associated liver disease (PNALD) is currently limited to conventional blood testing or liver biopsy. Metabolism of the stable isotope L[1-¹³C]methionine occurs exclusively in liver mitochondria and can be noninvasively quantified in expired breath samples. We hypothesized that the ¹³C-methionine breath test (¹³C-MBT) could be a safe, noninvasive, and valid measure of hepatic mitochondrial function in children with SBS and PNALD.

Methods

Baseline breath samples were collected in 8 children with SBS before intravenous administration of 2 mg/kg of L[1-¹³C]methionine. Six paired breath samples were obtained at 20-minute intervals. The ¹³CO₂ enrichment was analyzed using isotope ratio mass spectrometry.

Results

All 8 patients (5 males; mean age, 8.9 months) tolerated the ¹³C-MBT without adverse events. Two patients underwent serial testing. One patient, tested before and after resolution of cholestasis, demonstrated increased cumulative percentage dose (4.7% to 6.6%) and area under the curve (AUC) (270-303). A second patient with progressive PNALD demonstrated decreased cumulative percentage dose (from 7.8% to 5.9%) and AUC (from 335 to 288).

Conclusion

The ¹³C-MBT is a feasible, safe, and potentially clinically relevant measure of hepatic mitochondrial function in children with SBS and PNALD.     

Time-frequency balanced spectral entropy as a measure of anesthetic drug effect in central nervous system during sevoflurane, propofol, and thiopental anesthesia

BACKGROUND: Time-frequency balanced spectral entropy of electroencephalogram (EEG) and frontal electromyogram (FEMG) is a novel measure of hypnosis during anesthesia. Two Entropy parameters are described: Response entropy (RE) is calculated from EEG and FEMG; and State Entropy (SE) is calculated mainly from EEG. This study was performed to validate their performance during transition from consciousness to unconsciousness under different anesthetic agents. METHODS: Response entropy, SE [S/5 Entropy Module, M-ENTROPY (later in text: Entropy), Datex-Ohmeda Division, Instrumentarium Corp., Helsinki, Finland] and BIS (BIS XP, A-2000, Aspect Medical Systems, Newton, MA) data were collected from 70 patients; 30 anesthetized with propofol 2 mg kg-1, 20 with sevoflurane inhalation, and 20 with thiopental 5 mg kg-1. Loss and regaining of consciousness (LOC, ROC) was tested every 10 s, and sensitivity, specificity, and prediction probability (Pk) were calculated. Behavior of the indices was studied. RESULTS: Sensitivity, specificity, and Pk values for consciousness were high and similar for all indices. During regaining of consciousness after propofol bolus, RE, SE, and BIS values recovered by 81 +/- 22%, 75 +/- 26%, and 59 +/- 18% (mean +/- SD), respectively, from the minimum relative to their baseline. After thiopental bolus, RE, SE, and BIS values recovered by 86+/-21%, 88 +/- 13%, and 63 +/- 14%, respectively. The relative rise was higher in RE and SE compared with BIS (P < 0.01). During deep levels of hypnosis, RE and SE decreased monotonously as a function of burst suppression ratio, while BIS showed biphasic behavior. On average, RE indicated emergence from anesthesia 11 s earlier than SE, and 12.4 s earlier than BIS. CONCLUSIONS: All indices, RE, SE, and BIS, distinguished excellently between conscious and unconscious states during propofol, sevoflurane, and thiopental anesthesia. During burst suppression, Entropy parameters RE and SE, but not BIS, behave monotonously. During regaining of consciousness after a thiopental or propofol bolus, RE and SE values recovered significantly closer to their baseline values than did BIS. Response entropy indicates emergence from anesthesia earlier than SE or BIS.