A Prospective Multicenter Comparison of Trauma and Injury Severity Score, American Society of Anesthesiologists Physical Status, and National Surgical Quality Improvement Program Calculator's Ability to Predict Operative Trauma Outcomes

BACKGROUND

Trauma outcome prediction models have traditionally relied upon patient injury and physiologic data (eg, Trauma and Injury Severity Score [TRISS]) without accounting for comorbidities. We sought to prospectively evaluate the role of the American Society of Anesthesiologists physical status (ASA-PS) score and the National Surgical Quality Improvement Program Surgical Risk-Calculator (NSQIP-SRC), which are measurements of comorbidities, in the prediction of trauma outcomes, hypothesizing that they will improve the predictive ability for mortality, hospital length of stay (LOS), and complications compared to TRISS alone in trauma patients undergoing surgery within 24 hours.

METHODS

A prospective, observational multicenter study (9/2018-2/2020) of trauma patients ≥18 years undergoing operation within 24 hours of admission was performed. Multiple logistic regression was used to create models predicting mortality utilizing the variables within TRISS, ASA-PS, and NSQIP-SRC, respectively. Linear regression was used to create models predicting LOS and negative binomial regression to create models predicting complications.

RESULTS

From 4 level I trauma centers, 1213 patients were included. The Brier Score for each model predicting mortality was found to improve accuracy in the following order: 0.0370 for ASA-PS, 0.0355 for NSQIP-SRC, 0.0301 for TRISS, 0.0291 for TRISS+ASA-PS, and 0.0234 for TRISS+NSQIP-SRC. However, when comparing TRISS alone to TRISS+ASA-PS ( P = .082) and TRISS+NSQIP-SRC ( P = .394), there was no significant improvement in mortality prediction. NSQIP-SRC more accurately predicted both LOS and complications compared to TRISS and ASA-PS.

CONCLUSIONS

TRISS predicts mortality better than ASA-PS and NSQIP-SRC in trauma patients undergoing surgery within 24 hours. The TRISS mortality predictive ability is not improved when combined with ASA-PS or NSQIP-SRC. However, NSQIP-SRC was the most accurate predictor of LOS and complications.

Comparison of National Surgical Quality Improvement Program Surgical Risk Calculator and Trauma and Injury Severity Score Risk Assessment Tools in Predicting Outcomes in High-Risk Operative Trauma Patients

BACKGROUND

The Trauma and Injury Severity Score (TRISS) uses anatomic/physiologic variables to predict outcomes. The National Surgical Quality Improvement Program Surgical Risk Calculator (NSQIP-SRC) includes functional status and comorbidities. It is unclear which of these tools is superior for high-risk trauma patients (American Society of Anesthesiologists Physical Status (ASA-PS) class IV or V). This study compares risk prediction of TRISS and NSQIP-SRC for mortality, length of stay (LOS), and complications for high-risk operative trauma patients.

METHODS

This is a prospective study of high-risk (ASA-PS IV or V) trauma patients (≥18 years-old) undergoing surgery at 4 trauma centers. We compared TRISS vs NSQIP-SRC vs NSQIP-SRC + TRISS for ability to predict mortality, LOS, and complications using linear, logistic, and negative binomial regression.

RESULTS

Of 284 patients, 48 (16.9%) died. The median LOS was 16 days and number of complications was 1. TRISS + NSQIP-SRC best predicted mortality (AUROC: .877 vs .723 vs .843, P = .0018) and number of complications (pseudo-R2/median error (ME) 5.26%/1.15 vs 3.39%/1.33 vs 2.07%/1.41, P < .001) compared to NSQIP-SRC or TRISS, but there was no difference between TRISS + NSQIP-SRC and NSQIP-SRC with LOS prediction (P = .43).

DISCUSSION

For high-risk operative trauma patients, TRISS + NSQIP-SRC performed better at predicting mortality and number of complications compared to NSQIP-SRC or TRISS alone but similar to NSQIP-SRC alone for LOS. Thus, future risk prediction and comparisons across trauma centers for high-risk operative trauma patients should include a combination of anatomic/physiologic data, comorbidities, and functional status.

Comparison of National Surgical Quality Improvement Program Surgical Risk Calculator, Trauma and Injury Severity Score, and American Society of Anesthesiologists Physical Status to predict operative trauma mortality in elderly patients

BACKGROUND

The Trauma and Injury Severity Score (TRISS) uses anatomical and physiologic variables to predict mortality. Elderly (65 years or older) trauma patients have increased mortality and morbidity for a given TRISS, in part because of functional status and comorbidities. These factors are incorporated into the American Society of Anesthesiologists Physical Status (ASA-PS) and National Surgical Quality Improvement Program Surgical Risk Calculator (NSQIP-SRC). We hypothesized scoring tools using comorbidities and functional status to be superior at predicting mortality, hospital length of stay (LOS), and complications in elderly trauma patients undergoing operation.

METHODS

Four level I trauma centers prospectively collected data on elderly trauma patients undergoing surgery within 24 hours of admission. Using logistic regression, five scoring models were compared: ASA-PS, NSQIP-SRC, TRISS, TRISS-ASA-PS, and TRISS-NSQIP-SRC.Brier scores and area under the receiver operator characteristics curve were calculated to compare mortality prediction. Adjusted R2 and root mean squared error were used to compare LOS and predictive ability for number of complications.

RESULTS

From 122 subjects, 9 (7.4%) died, and the average LOS was 12.9 days (range, 1-110 days). National Surgical Quality Improvement Program Surgical Risk Calculator was superior to ASA-PS and TRISS at predicting mortality (area under the receiver operator characteristics curve, 0.978 vs. 0.768 vs. 0.903; p = 0.007). Furthermore, NSQIP-SRC was more accurate predicting LOS (R2, 25.9% vs. 13.3% vs. 20.5%) and complications (R2, 34.0% vs. 22.6% vs. 29.4%) compared with TRISS and ASA-PS. Adding TRISS to NSQIP-SRC improved predictive ability compared with NSQIP-SRC alone for complications (R2, 35.5% vs. 34.0%; p = 0.046). However, adding ASA-PS or TRISS to NSQIP-SRC did not improve the predictive ability for mortality or LOS.

CONCLUSION

The NSQIP-SRC, which includes comorbidities and functional status, had superior ability to predict mortality, LOS, and complications compared with TRISS alone in elderly trauma patients undergoing surgery.

LEVEL OF EVIDENCE

Prognostic and Epidemiologic; Level III.

Blood preservation techniques in complex spine surgery: Illustrative case and review of therapeutic options

Background:

Complex spine surgery predisposes patients to substantial levels of blood loss, which can increase the risk of surgical morbidity and mortality.

Case Description:

A 29-year-old achondroplastic male required thoracolumbar deformity correction. However, he refused potential allogeneic blood transfusions for religious reasons. He, therefore, underwent pre-operative autologous blood donation and consented to the use of the intraoperative cell salvage device. Immediately prior to the incision, he underwent acute normovolemic hemodilution. Throughout the case, we additionally utilized meticulous hemostasis. Postoperatively, he was supplemented with iron and erythropoietin and recovered well. When he required a revision procedure 3 months later, similar strategies were successfully employed.

Conclusion:

Numerous strategies exist pre-operatively, intraoperatively, and post-operatively to optimize blood loss management for patients who refuse blood transfusions but warrant major spinal deformity surgery.

A Positive Cocaine Urine Toxicology Test and the Effect on Intraoperative Hemodynamics Under General Anesthesia

BACKGROUND

Cocaine has a short biological half-life, but inactive urine metabolites may be detectable for a week following use. It is unclear if patients who test positive for cocaine but have a normal electrocardiogram and vital signs have a greater percentage of hemodynamic events intraoperatively.

METHODS

A total of 328 patients with a history of cocaine use who were scheduled for elective noncardiac surgery under general anesthesia were enrolled. Patients were categorized into cocaine-positive versus cocaine-negative groups based on the results of their urine cocaine toxicology test. The primary aim of this study was to evaluate whether asymptomatic cocaine-positive patients had similar percentages of intraoperative hemodynamic events, defined as (1) a mean arterial blood pressure (MAP) of <65 or >105 mm Hg and (2) a heart rate (HR) of <50 or >100 beats per minute (bpm) compared to cocaine-negative patients. The study was powered to assess if the 2 groups had an equivalent mean percent of intraoperative hemodynamic events within specific limits using an equivalence test of means consisting of 2 one-sided tests.

RESULTS

The cocaine-positive group had a blood pressure (BP) that was outside the set limits 19.4% (standard deviation [SD] 17.7%) of the time versus 23.1% (SD 17.7%) in the cocaine-negative group (95% confidence interval [CI], 0.5-7.0). The cocaine-positive group had a HR outside the set limits 9.6% (SD 16.2%) of the time versus 8.2% (SD 14.9%) in the cocaine-negative group (95% CI, 4.3-1.5). Adjusted for age, sex, body mass index (BMI), smoking status, and the presence of comorbid hypertension, renal disease, and psychiatric illness, the cocaine-positive and cocaine-negative patients were similar within a 7.5% margin of equivalence for MAP data (β coefficient = 2%, P = .003, CI, 2-6) and within a 5% margin of equivalence for HR data (β coefficient = 0.2%, P < .001, CI, 4-3).

CONCLUSIONS

Asymptomatic cocaine-positive patients undergoing elective noncardiac surgery under general anesthesia have similar percentages of intraoperative hemodynamic events compared to cocaine-negative patients.

Media supplementation for targeted manipulation of monoclonal antibody galactosylation and fucosylation

Monoclonal antibodies are critically important biologics as the largest class of molecules used to treat cancers, rheumatoid arthritis, and other chronic diseases. Antibody glycosylation is a critical quality attribute that has ramifications for patient safety and physiological efficacy-one that can be modified by such factors as media formulation and process conditions during production. Using a design-of-experiments approach, we examined the effect of 2-F-peracetyl fucose (2FP), uridine, and galactose on cell growth and metabolism, titer, and gene expression of key glycosylation-related proteins, and report how the glycoform distribution changed from Days 4 to 7 in a batch process used for IgG1 production from Chinese hamster ovary cells. We observed major glycosylation changes upon supplement addition, where the addition of 2FP decreased antibody fucosylation by up to 48%, galactose addition increased galactosylation by up to 21%, and uridine addition decreased fucosylation and increased galactosylation by 6% and 2%, respectively. Despite having major effects on glycosylation, neither galactose nor 2FP significantly affected cell culture growth, metabolism, or titer. Uridine improved peak cell densities by 23% but also reduced titer by ∼30%. The supplements caused significant changes in gene expression by Day 4 of the cultures where 2FP addition significantly reduced fucosyltransferase 8 and nucleotide sugar transporter gene expression (by ∼2-fold), and uridine addition significantly increased expression of UDP-GlcNAcT (SLC35A3) and B4GALT1-6 genes (by 1.5-3-fold). These gene expression data alongside glycosylation, metabolic, and growth data improve our understanding of the cellular mechanisms affected by media supplementation and suggest approaches for modifying antibody glycosylation in antibody production processes.

Investigating the Effects of Brainstem Neuronal Adaptation on Cardiovascular Homeostasis

Central coordination of cardiovascular function is accomplished, in part, by the baroreceptor reflex, a multi-input multi-output physiological control system that regulates the activity of the parasympathetic and sympathetic nervous systems via interactions among multiple brainstem nuclei. Recent single-cell analyses within the brain revealed that individual neurons within and across brain nuclei exhibit distinct transcriptional states contributing to neuronal function. Such transcriptional heterogeneity complicates the task of understanding how neurons within and across brain nuclei organize and function to process multiple inputs and coordinate cardiovascular functions within the larger context of the baroreceptor reflex. However, prior analysis of brainstem neurons revealed that single-neuron transcriptional heterogeneity reflects an adaptive response to synaptic inputs and that neurons organize into distinct subtypes with respect to synaptic inputs received. Based on these results, we hypothesize that adaptation of neuronal subtypes support robust biological function through graded cellular responses. We test this hypothesis by examining the functional impact of neuronal adaptation on parasympathetic activity within the context of short-term baroreceptor reflex regulation. In this work, we extend existing quantitative closed-loop models of the baroreceptor reflex by incorporating into the model distinct input-driven neuronal subtypes and neuroanatomical groups that modulate parasympathetic activity. We then use this extended model to investigate, via simulation, the functional role of neuronal adaptation under conditions of health and systolic heart failure. Simulation results suggest that parasympathetic activity can be modulated appropriately by the coordination of distinct neuronal subtypes to maintain normal cardiovascular functions under systolic heart failure conditions. Moreover, differing degrees of adaptation of these neuronal subtypes contribute to cardiovascular behaviors corresponding to distinct clinical phenotypes of heart failure, such as exercise intolerance. Further, our results suggest that an imbalance between sympathetic and parasympathetic activity regulating ventricular contractility contributes to exercise intolerance in systolic heart failure patients, and restoring this balance can improve the short-term cardiovascular performance of these patients.

Sugammadex versus neostigmine for reversal of rocuronium-induced neuromuscular blockade: A randomized, double-blinded study of thoracic surgical patients evaluating hypoxic episodes in the early postoperative period

STUDY OBJECTIVE

This objective of this study was to determine if reversal of rocuronium-induced neuromuscular blockade with sugammadex versus neostigmine results in a decreased number of hypoxic episodes in the early postoperative period in patients undergoing thoracic surgery with single lung ventilation.

DESIGN

Single-center, randomized, double-blind, two-arm clinical trial.

SETTING

Operating room and postanesthesia care unit.

PATIENTS

92 subjects aged ≥18, American Society of Anesthesiologists physical status II-IV, and undergoing a thoracic operation necessitating single lung ventilation.

INTERVENTIONS

Subjects received either 2 mg/kg sugammadex or 50 μg/kg neostigmine with 8 μg/kg glycopyrrolate for reversal of moderate neuromuscular blockade.

MEASUREMENTS

For the first 90 min postoperatively, all episodes of hypoxia were recorded. Neuromuscular monitoring was performed with acceleromyography (TOF-Watch® SX) and the train of four (TOF) was recorded at 2, 5, 10, and 15 min after administration of the neuromuscular reversal agent.

MAIN RESULTS

Subjects who received neostigmine had a median of 1 episode (interquartile range IQR: 0-2.2) of hypoxia versus subjects who received sugammadex who had a median of 0 episodes (IQR: 0-1) (p = 0.009). The mean time to recovery of TOF ≥ 0.9 was significantly faster with sugammadex at 10 min (95% confidence interval CI: 5-15) compared with neostigmine at 40 min (95% CI: 15-53) (p < 0.001).

CONCLUSIONS

In thoracic surgical patients necessitating single lung ventilation, sugammadex provides faster reversal of moderate neuromuscular blockade and results in a decreased number of postoperative hypoxic episodes compared with neostigmine.

Clonidine, but not Dexamethasone, Prolongs Ropivacaine-Induced Supraclavicular Brachial Plexus Nerve Block Duration

BACKGROUND

Ultrasound-guided supraclavicular brachial plexus block (USSB) provides excellent postoperative analgesia after upper extremity surgery. Dexamethasone and clonidine have been added to local anesthetics to enhance and prolong the duration of analgesia.

OBJECTIVE

The objective of this randomized prospective study is to evaluate the efficacy of dexamethasone, clonidine, or combination of both as adjuvants to ropivacaine on the duration of USSB for postoperative analgesia.

METHODS

Patients receiving USSB for postoperative pain control for upper extremity surgery were randomized to one of four groups; ropivacaine 0.5%, ropivacaine 0.5% with 4 mg dexamethasone, ropivacaine 0.5% with 100 mcg clonidine , or ropivacaine 0.5% with 4 mg dexamethasone and 100 mcg clonidine. Pain scores, sensory and motor function were evaluated at post anesthesia care unit (PACU), discharge and at 24 h postoperatively.

RESULTS

The duration of sensory and motor blocks was significantly longer in clonidine groups when compared to ropivacaine alone [Sensorial analgesia: ropivacaine alone 13.4±6, Ropivacaine- Clonidine 17.4±6; Ropivacaine-Dexamethasone-Clonidine 18.8±6.2; Motor blocks: Ropivacaine 12±5, Ropivacaine-Clonidine 16.8±5.2, Ropivacaine-Dexamethasone-Clonidine 18.2±5.7]. In clonidine groups, there was significant prolongation of motor and sensory block when compared to ropivacaine group alone.

CONCLUSION

The results demonstrated that clonidine significantly prolongs the duration of ropivacaine effects for the postoperative analgesia in patient underwent upper arm surgeries.

Adiponectin fine-tuning of liver regeneration dynamics revealed through cellular network modelling

Following partial hepatectomy, the liver initiates a regenerative programme involving hepatocyte priming and replication driven by the coordinated actions of cytokine and growth factors. We investigated the mechanisms underlying adiponectin's (Adn) regulation of liver regeneration through modulation of these mediators. Adn(-/-) mice showed delayed onset of hepatocyte replication, but accelerated cell cycle progression relative to wild-type mice, suggesting Adn has multiple effects fine-tuning the kinetics of liver regeneration. We developed a computational model describing the molecular and physiological kinetics of liver regeneration in Adn(-/-) mice. We employed this computational model to evaluate the underlying regulatory mechanisms. Our analysis predicted that Adn is required for an efficient early cytokine response to partial hepatectomy, but is inhibitory to later growth factor actions. Consistent with this prediction, Adn knockout reduced hepatocyte responses to interleukin-6 during the priming phase, but enhanced growth factor levels through peak hepatocyte replication. By contrast, supraphysiological concentrations of Adn resulting from rosiglitazone treatment suppressed regeneration by reducing growth factor levels during S phase, consistent with computational predictions. Together, these results revealed that Adn fine-tunes the progression of liver regeneration through dynamically modulating molecular mediator networks and cellular interactions within the liver.

Identifying functional gene regulatory network phenotypes underlying single cell transcriptional variability

Recent analysis of single-cell transcriptomic data has revealed a surprising organization of the transcriptional variability pervasive across individual neurons. In response to distinct combinations of synaptic input-type, a new organization of neuronal subtypes emerged based on transcriptional states that were aligned along a gradient of correlated gene expression. Individual neurons traverse across these transcriptional states in response to cellular inputs. However, the regulatory network interactions driving these changes remain unclear. Here we present a novel fuzzy logic-based approach to infer quantitative gene regulatory network models from highly variable single-cell gene expression data. Our approach involves developing an a priori regulatory network that is then trained against in vivo single-cell gene expression data in order to identify causal gene interactions and corresponding quantitative model parameters. Simulations of the inferred gene regulatory network response to experimentally observed stimuli levels mirrored the pattern and quantitative range of gene expression across individual neurons remarkably well. In addition, the network identification results revealed that distinct regulatory interactions, coupled with differences in the regulatory network stimuli, drive the variable gene expression patterns observed across the neuronal subtypes. We also identified a key difference between the neuronal subtype-specific networks with respect to negative feedback regulation, with the catecholaminergic subtype network lacking such interactions. Furthermore, by varying regulatory network stimuli over a wide range, we identified several cases in which divergent neuronal subtypes could be driven towards similar transcriptional states by distinct stimuli operating on subtype-specific regulatory networks. Based on these results, we conclude that heterogenous single-cell gene expression profiles should be interpreted through a regulatory network modeling perspective in order to separate the contributions of network interactions from those of cellular inputs.

Inputs drive cell phenotype variability

What is the significance of the extensive variability observed in individual members of a single-cell phenotype? This question is particularly relevant to the highly differentiated organization of the brain. In this study, for the first time, we analyze the in vivo variability within a neuronal phenotype in terms of input type. We developed a large-scale gene-expression data set from several hundred single brainstem neurons selected on the basis of their specific synaptic input types. The results show a surprising organizational structure in which neuronal variability aligned with input type along a continuum of sub-phenotypes and corresponding gene regulatory modules. Correlations between these regulatory modules and specific cellular states were stratified by synaptic input type. Moreover, we found that the phenotype gradient and correlated regulatory modules were maintained across subjects. As these specific cellular states are a function of the inputs received, the stability of these states represents “attractor”-like states along a dynamic landscape that is influenced and shaped by inputs, enabling distinct state-dependent functional responses. We interpret the phenotype gradient as arising from analog tuning of underlying regulatory networks driven by distinct inputs to individual cells. Our results change the way we understand how a phenotypic population supports robust biological function by integrating the environmental experience of individual cells. Our results provide an explanation of the functional significance of the pervasive variability observed within a cell type and are broadly applicable to understanding the relationship between cellular input history and cell phenotype within all tissues.

Protein local conformations arise from a mixture of Gaussian distributions

The classical approaches for protein structure prediction rely either on homology of the protein sequence with a template structure or on ab initio calculations for energy minimization. These methods suffer from disadvantages such as the lack of availability of homologous template structures or intractably large conformational search space, respectively. The recently proposed fragment library based approaches first predict the local structures,which can be used in conjunction with the classical approaches of protein structure prediction. The accuracy of the predictions is dependent on the quality of the fragment library. In this work, we have constructed a library of local conformation classes purely based on geometric similarity. The local conformations are represented using Geometric Invariants, properties that remain unchanged under transformations such as translation and rotation, followed by dimension reduction via principal component analysis. The local conformations are then modeled as a mixture of Gaussian probability distribution functions (PDF). Each one of the Gaussian PDF's corresponds to a conformational class with the centroid representing the average structure of that class. We find 46 classes when we use an octapeptide as a unit of local conformation. The protein 3-D structure can now be described as a sequence of local conformational classes. Further, it was of interest to see whether the local conformations can be predicted from the amino acid sequences. To that end,we have analyzed the correlation between sequence features and the conformational classes.

Effect of short-term postoperative celecoxib administration on patient outcome after outpatient laparoscopic surgery

PURPOSE

Non-opioid analgesics are increasingly used as part of a multimodal regimen for pain management. This prospective, randomized, double-blinded, placebo-controlled study was designed to evaluate the effect of short-term postoperative administration of celecoxib on pain management and recovery outcomes following laparoscopic surgery.

METHODS

Eighty consenting ASA I-III outpatients undergoing laparoscopic surgery were randomly assigned to one of two treatment groups: Control (placebo) or Celecoxib (celecoxib, 400 mg x day(-1)). The initial dose (celecoxib 400 mg or placebo po) was administered in the recovery room, and celecoxib 200 mg (or a placebo) po bid was continued for three additional days after surgery. Postoperative pain scores and the need for opioid- containing analgesics were recorded at specific intervals in the recovery room. Follow-up evaluations were performed at 24 hr, 48 hr, 72 hr and seven days and one month after surgery to assess post-discharge pain, analgesic requirements, complications, quality of recovery, and resumption of normal activities, as well as patient satisfaction with their pain management.

RESULTS

Celecoxib reduced mean pain scores and the need for analgesics at 24 hr and 48 hr postoperatively. Patient satisfaction with their postoperative pain management was also higher in the Celecoxib group (94 +/- 8 vs 80 +/- 25, P<0.05). Quality of recovery scores were significantly higher in the Celecoxib group on the first and second postoperative days (17 +/- 1 vs 15 +/- 2, and 18 +/- 1 vs 16 +/- 2, respectively). Finally, bowel function recovered an average of one day earlier and patients resumed activities of daily living two days earlier in the Celecoxib group (P<0.05).

CONCLUSION

Short-term administration of celecoxib, 400 mg x day(-1) po, decreased postoperative pain and the need for opioid-containing analgesic medication, leading to an improved quality of recovery after outpatient laparoscopic surgery.

Transdermal Scopolamine: An Alternative to Ondansetron and Droperidol for the Prevention of Postoperative and Postdischarge Emetic Symptoms

BACKGROUND

Given the controversy regarding the use of droperidol and the high cost of the 5-HT3 antagonists, a cost-effective alternative for routine use as a prophylactic antiemetic would be desirable. We designed two parallel, randomized, double-blind sham and placebo-controlled studies to compare the early and late antiemetic efficacy and adverse event profile of transdermal scopolamine (TDS) 1.5 mg, to ondansetron 4 mg IV, and droperidol 1.25 mg IV for antiemetic prophylaxis as part of a multimodal regimen in "at risk" surgical populations.

METHODS

A total of 150 patients undergoing major laparoscopic (n = 80) or plastic (n = 70) surgery procedures received either an active TDS patch (containing scopolamine 1.5 mg) or a similar appearing sham patch 60 min before entering the operating room. All patients received a standardized general anesthetic technique. A second study medication was administered in a 2-mL numbered syringe containing either saline (for the two active TDS groups), droperidol, 1.25 mg, or ondansetron, 4 mg (for the sham patch groups), and was administered IV near the end of the procedure. The occurrence of postoperative nausea and vomiting/retching, need for rescue antiemetics, and the complete response rates (i.e., absence of protracted nausea or repeated episodes of emesis requiring antiemetic rescue medication) was reported. In addition, complaints of visual disturbances, dry mouth, drowsiness, and restlessness were noted up to 72 h after surgery.

RESULTS

There were no significant differences in any of the emetic outcomes or need for rescue antiemetics among the TDS, droperidol, and ondansetron groups in the first 72 h after surgery. The complete response rates varied from 41% to 51%, and did not significantly differ among the treatment groups. The overall incidence of dry mouth was significantly more frequent in the TDS groups than in the droperidol and ondansetron groups (21% vs 3%).

CONCLUSIONS

Premedication with TDS was as effective as droperidol (1.25 mg) or ondansetron (4 mg) in preventing nausea and vomiting in the early and late postoperative periods. However, the use of a TDS patch is more likely to produce a dry mouth.

The Use of Oral Granisetron Versus Intravenous Ondansetron for Antiemetic Prophylaxis in Patients Undergoing Laparoscopic Surgery: The Effect on Emetic Symptoms and Quality of Recovery

Based on comparative studies in patients receiving emetogenic chemotherapy, it has been suggested that granisetron would be more effective than ondansetron for the prevention of postdischarge nausea and vomiting (PDNV). However, there have been no direct comparisons of these two popular 5-HT3 antagonists with respect to PDNV and quality of recovery. We designed this randomized, double-blind study to compare the antiemetic efficacy of oral granisetron (1 mg) to a standard IV dose of ondansetron (4 mg) when administered for antiemetic prophylaxis as part of a multimodal regimen in a laparoscopic surgical population. A total of 220 patients undergoing laparoscopic surgery with a standardized general anesthetic technique were enrolled in this prospective study at two major medical centers. Patients were randomly assigned to one of two prophylactic treatment groups: the control (ondansetron) group received an oral placebo 1 h before surgery and ondansetron, 4 mg IV, at the end of the surgery, and the granisetron group received granisetron, 1 mg per os, 1 h before surgery, and normal saline, 2 mL IV, at the end of the surgery. The early recovery profiles, requirement for rescue antiemetics, incidence of PDNV, and the side effects were recorded over the 48 h study period. In addition, nausea scores were assessed using an 11-point verbal rating scale at specific intervals in the postoperative period. The quality of recovery and patient satisfaction scores were recorded at 48 h after surgery. The demographic characteristics were similar in the two prophylaxis treatment groups, as well as the recovery times to patient orientation, oral intake, and hospital discharge. The incidences of PDNV, requirements for rescue antiemetics, and quality of recovery did not differ between the two study groups. The antiemetic drug acquisition costs to achieve comparable patient satisfaction with ondansetron and granisetron were US 25.65 dollars and 47.05 dollars, respectively. Therefore, ondansetron (4 mg IV) was more cost-effective than granisetron (1 mg per os) for routine antiemetic prophylaxis as part of a multimodal regimen in patients undergoing either outpatient or inpatient laparoscopic surgery.

Gaussian mixture modeling of alpha-helix subclasses: structure and sequence variations

Classification of helical structures and identification of class specific sequence features is of interest for protein structure modeling. We use geometric invariant based method to first select helix-like local conformations. These conformations are mapped in a principal component space and subjected to Gaussian mixture modeling. The largest Gaussian corresponds to the regular alpha-helix. Kinked helix and curved helix appear as a separate gaussians. Class conditional, position specific amino acid propensity analysis reveals striking difference among the three classes. In regular helix, proline propensity is significant only in the beginning and low in the rest of the region regardless of length of the helix. In kinked helix, the proline propensity has a sharp peak at the helix center, while in the curved helix, the proline propensity has a broad peak in the middle region.

A geometric invariant-based framework for the analysis of protein conformational space

MOTIVATION

Characterization of the restricted nature of the protein local conformational space has remained a challenge, thereby necessitating a computationally expensive conformational search in protein modeling. Moreover, owing to the lack of unilateral structural descriptors, conventional data mining techniques, such as clustering and classification, have not been applied in protein structure analysis.

RESULTS

We first map the local conformations in a fixed dimensional space by using a carefully selected suite of geometric invariants (GIs) and then reduce the number of dimensions via principal component analysis (PCA). Distribution of the conformations in the space spanned by the first four PCs is visualized as a set of conditional bivariate probability distribution plots, where the peaks correspond to the preferred conformations. The locations of the different canonical structures in the PC-space have been interpreted in the context of the weights of the GIs to the first four PCs. Clustering of the available conformations reveals that the number of preferred local conformations is several orders of magnitude smaller than that suggested previously.

SUPPLEMENTARY INFORMATION

www.it.iitb.ac.in/~ashish/bioinfo2005/.

Heated and humidified insufflation during laparoscopic gastric bypass surgery: effect on temperature, postoperative pain, and recovery outcomes

BACKGROUND

Controversy exists regarding the efficacy of heated and humidified intraperitoneal gases in maintaining core body temperature. We performed a sham-controlled study to test the hypothesis that active warming and humidification of the insufflation gas reduces intraoperative heat loss and improves recovery outcomes.

PATIENTS AND METHODS

Fifty morbidly obese patients undergoing laparoscopic Roux-en-Y gastric bypass procedures using a standardized anesthetic technique were randomly assigned to either a control (sham) group receiving room temperature insufflation gases with an inactive Insuflow (Lexion Medical, St. Paul, MN) device, or an active (Insuflow) group receiving warmed and humidified intraperitoneal gases. Esophageal and/or tympanic membrane temperature was measured perioperatively. Postoperative pain was assessed at 15 minute intervals using an 11-point verbal rating scale, with 0 = none to 10 = maximal. In addition, postoperative opioid requirements, incidence of nausea and vomiting, as well as the quality of recovery, were recorded.

RESULTS

Use of the active Insuflow device was associated with significantly higher mean +/- standard deviation (SD) intraoperative core body temperatures (35.5 +/- 0.5 vs. 35.0 +/- 0.4 degrees C). Postoperative shivering (0 vs. 19%) and the requirement for morphine in the postanesthesia care unit (5 +/- 4 vs. 10 +/- 5 mg) were both significantly lower in the Insuflow vs. control groups. Patients in the Insuflow group also reported a higher quality of recovery 48 hours after surgery (15 vs. 13, P < 0.05).

CONCLUSION

The Insuflow device modestly reduced shivering and heat loss, as well as the need for opioid analgesics in the early postoperative period. However, it failed to improve laparoscopic visualization due to fogging, and provided improvement in the quality of recovery only on postoperative day 2.

Digital quantitative measurements of gene expression

One of the primary goals of functional genomics is to provide a quantitative understanding of gene function. However, the success of this enterprise is dependent on the accuracy and precision of the functional genomic data. A novel approach, digital analysis of gene expression (DAGE) described herein, is an accurate and precise technology for measuring digital gene expression on a relative or absolute scale by simply counting the number of transcripts of a gene being expressed at a given time. The result is a greatly improved technology sensitive enough for identifying and quantifying small (but biologically important and statistically relevant) changes in gene expression. Fourteen genes involved in galactose metabolism in Saccharomyces cerevisiae were analyzed for their expression levels in glucose and galactose minimal media. The quantitative expression results were characterized in terms of distributional and accuracy attributes; they were also in general agreement (in terms of direction of change) with corresponding results obtained using microarray technology. DAGE is likely to have profound implications in the field of functional genomics because the gene expression measurements are digital in nature and therefore more accurate than any other technologies.

The effect of cerebral monitoring on recovery after general anesthesia: a comparison of the auditory evoked potential and bispectral index devices with standard clinical practice

The use of cerebral monitoring may improve the ability of anesthesiologists to titrate anesthetic drugs. However, there is controversy regarding the impact of the alleged anesthetic-sparing effects of cerebral monitoring on the recovery process and patient outcome. We designed this prospective double-blinded, sham-controlled study to evaluate the impact of intraoperative monitoring with the electroencephalogram bispectral index (BIS) or auditory evoked potential (AEP) device on the usage of desflurane and the time to discharge from the recovery room, as well as on patient satisfaction with their anesthetic experience and recovery. Ninety healthy patients undergoing laparoscopic general surgery procedures using a standardized anesthetic technique were randomly assigned to one of three monitoring groups: standard clinical practice (control), BIS-guided, or AEP-guided. Both the BIS and AEP monitors were connected to all patients before induction of general anesthesia. In the control group, the anesthesiologists were not permitted to observe the BIS or AEP index values during the intraoperative period. In the BIS-guided group, the volatile anesthetic was titrated to maintain a BIS value in the range of 45-55. In the AEP-guided group, the targeted AEP index range was 15-20. The BIS and AEP indices, as well as end-tidal desflurane concentration, were recorded at 3-5 min intervals. Recovery times to awakening, tracheal extubation, fast-track score >or=12, and postanesthesia care unit (PACU) discharge criteria were recorded at 1-10 min intervals. In addition, patient satisfaction with anesthesia and quality of recovery were evaluated on 100- and 18-point scales, respectively, at 24 h after surgery. The AEP- and BIS-guided groups were administered significantly smaller average end-tidal desflurane concentrations than the control group (3.8 +/- 0.9 and 3.9 +/- 0.6 versus 4.7 +/- 1.7, respectively) (P < 0.01). Although the emergence times to eye opening, tracheal extubation, and obeying commands were consistently shorter in the AEP and BIS groups (6 +/- 4 and 6 +/- 5 versus 8 +/- 8 min; 6 +/- 5 and 6 +/- 4 versus 11 +/- 10 min; and 8 +/- 4 and 7 +/- 4 versus 12 +/- 9 min, respectively), only the extubation times were significantly different from the control group (P < 0.05). More importantly, the length of the PACU stay was significantly shorter in both the AEP- and BIS-guided groups (79 +/- 43 and 80 +/- 47 versus 108 +/- 58 min, respectively) (P < 0.05). The patients' quality of recovery was also significantly higher in the two monitored groups (15 +/- 2 versus 13 +/- 3 in the control group, P < 0.05). We concluded that cerebral monitoring with either the BIS or AEP devices reduced the maintenance anesthetic (desflurane) requirement, resulting in a shorter length of stay in the PACU and improved quality of recovery after laparoscopic surgery. However, there were no significant outcome differences between the two cerebral monitored groups.

IMPLICATIONS

Compared with standard monitoring practices, use of an auditory evoked potential or bispectral index monitor to titrate the volatile anesthetic led to a significant reduction in the anesthetic requirement. The anesthetic-sparing effect of cerebral monitoring resulted in a shorter postanesthesia care unit stay and improved quality of recovery from the patient's perspective.