bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nasotracheal Intubation
Authors: Elwood Tom , Stillions Duane M. , Woo Dawn W. , Bradford Heidi M. , Ramamoorthy Chandra 
Published: November 2003

Background
Several techniques have been suggested to reduce the trauma of nasotracheal intubation, although no comparative studies exist. The authors evaluated red-rubber catheters as a guide to nasotracheal intubation.

Methods
Children presenting for elective surgery were randomized to undergo red-rubber catheter-guided nasotracheal intubation or to have the nasotracheal tube alone inserted. After general anesthesia and paralysis with vecuronium, the nares were prepared with topical vasoconstrictor. The nasotracheal tube was softened with warm water. In the catheter-guided group, the nasotracheal tube tip was fitted to the trailing end of the red-rubber catheter, and the two were advanced together. The red-rubber catheter was retrieved from the nasopharynx, disconnected, and removed. In the other group, the nasotracheal tube was advanced blindly into the nasopharynx. In both groups, intubation was then completed during direct laryngoscopy using Magill forceps. A blinded observer swabbed the pharynx and rated the severity of bleeding based on reference photographs.

Results
Age, weight, snoring history, and difficulty of intubation were not different between groups. Obvious bleeding was lower using the red-rubber catheter technique (10 vs. 29%, P = 0.013), which took longer to perform (74 vs. 56 s, P = 0.02).

Conclusions
Although the incidence of bleeding in both groups was similar, severity of bleeding was reduced in the catheter-guided group during nasotracheal intubation. Use of a red-rubber catheter may reduce the trauma associated with nasotracheal intubation.
Intracarotid Nitroprusside Does Not Augment Cerebral Blood Flow in Human Subjects
Authors: Joshi Shailendra , Young William L. , Duong Huang , Aagaard Beverly A. , Ostapkovich Noeleen D. , Connolly E. Sander , Pile-Spellman John 
Published: November 2003

Background
The recent resurgence of interest in the cerebrovascular effects of nitroprusside can be attributed to the possibility of using nitric oxide donors in treating cerebrovascular insufficiency. However, limited human data suggest that intracarotid nitroprusside does not directly affect cerebrovascular resistance. In previous studies, physiologic or pharmacologic reactivity of the preparation was not tested at the time of nitroprusside challenge. The authors hypothesized that if nitric oxide is a potent modulator of human cerebral blood flow (CBF), then intracarotid infusion of nitroprusside will augment CBF.

Methods
Cerebral blood flow was measured (intraarterial (133)Xe technique) in sedated human subjects undergoing cerebral angiography during sequential infusions of (1) intracarotid saline, (2) intravenous phenylephrine to induce systemic hypertension, (3) intravenous phenylephrine with intracarotid nitroprusside (0.5 microg x kg(-1) x min(-1)), and (4) intracarotid verapamil (0.013 mg x kg(-1) x min(-1)). Data (mean +/- SD) were analyzed by repeated-measures analysis of variance and post hoc Bonferroni-Dunn test.

Results
Intravenous phenylephrine increased systemic mean arterial pressure (from 83 +/- 12 to 98 +/- 6 mmHg; n = 8; P < 0.001), and concurrent infusion of intravenous phenylephrine and intracarotid nitroprusside reversed this effect. However, compared with baseline, CBF did not change with intravenous phenylephrine or with concurrent infusions of intravenous phenylephrine and intracarotid nitroprusside. Intracarotid verapamil increased CBF (43 +/- 9 to 65 +/- 11 ml x 100 g(-1) x min(-1); P < 0.05).

Conclusions
The authors conclude that, in humans, intracarotid nitroprusside sufficient to decrease mean arterial pressure during recirculation, does not augment CBF. Failure of intracarotid nitroprusside to augment CBF despite demonstrable autoregulatory vasoconstriction and pharmacologic vasodilation questions the significance of nitric oxide-mediated vasodilation in human cerebral circulation.
Continuous Positive Airway Pressure in New-generation Mechanical Ventilators
Authors: Takeuchi Muneyuki , Williams Purris , Hess Dean , Kacmarek Robert M. 
Published: November 2003

Background
A number of new microprocessor-controlled mechanical ventilators have become available over the last few years. However, the ability of these ventilators to provide continuous positive airway pressure without imposing or performing work has never been evaluated.

Methods
In a spontaneously breathing lung model, the authors evaluated the Bear 1000, Drager Evita 4, Hamilton Galileo, Nellcor-Puritan-Bennett 740 and 840, Siemens Servo 300A, and Bird Products Tbird AVS at 10 cm H(2)O continuous positive airway pressure. Lung model compliance was 50 ml/cm H(2)O with a resistance of 8.2 cm H(2)O x l(-1) x s(-1), and inspiratory time was set at 1.0 s with peak inspiratory flows of 40, 60, and 80 l/min. In ventilators with both pressure and flow triggering, the response of each was evaluated.

Results
With all ventilators, peak inspiratory flow, lung model tidal volume, and range of pressure change (below baseline to above baseline) increased as peak flow increased. Inspiratory trigger delay time, inspiratory cycle delay time, expiratory pressure time product, and total area of pressure change were not affected by peak flow, whereas pressure change to trigger inspiration, inspiratory pressure time product, and trigger pressure time product were affected by peak flow on some ventilators. There were significant differences among ventilators on all variables evaluated, but there was little difference between pressure and flow triggering in most variables on individual ventilators except for pressure to trigger. Pressure to trigger was 3.74 +/- 1.89 cm H(2)O (mean +/- SD) in flow triggering and 4.48 +/- 1.67 cm H(2)O in pressure triggering (P < 0.01) across all ventilators.

Conclusions
Most ventilators evaluated only imposed a small effort to trigger, but most also provided low-level pressure support and imposed an expiratory workload. Pressure triggering during continuous positive airway pressure does require a slightly greater pressure than flow triggering.
Economic Evaluation of Propofol for Sedation of Patients Admitted to Intensive Care Units
Authors: Anis Aslam H. , Wang Xiao-hua , Leon Hector , Hall Richard 
Published: November 2003

Background
The goal of the current study was to evaluate the economic impact of propofol as compared with midazolam for sedating patients in the intensive care unit (ICU).

Methods
A randomized, unblinded, multicenter pharmacoeconomic trial captured health resource utilization and outcome measurements associated with sedation and treatment of patients in four ICUs across Canada. Statistical analysis was performed to investigate the difference in sedation quality, ICU length of stay, and other health resources used. The authors compared the costs (1997 Canadian dollars) associated with the two treatments. Two types of sensitivity analyses were performed.

Results
Although overall sedation duration was similar, propofol patients spent more time at adequately sedated status (60.2% vs. 44%; P = 0.01) and were extubated faster (median extubation time, 2.5 vs. 7.1 h; P = 0.001). The ICU length of stay and health resource utilization did not differ. The total cost per patient, including drug cost and ICU stay cost, did not differ between groups (median, $5,718 for propofol vs. $5,950 for midazolam; P = 0.94). The first sensitivity analysis suggested that the incremental cost (per patient) of propofol varies from an extra cost of $114 to a savings of $2,709. Based on a hypothetical model, the second sensitivity analysis showed a potential saving of $479 per patient as a result of improved discharge planning.

Conclusion
The analysis demonstrated that using propofol resulted in a reduction of time to extubation and higher sedative regimen costs. There was no difference in intensity of resource use or ICU length of stay and hence in costs. Issues regarding discharge delay among propofol-treated patients remain to be explored.
Absence of Beneficial Effect of Acute Normovolemic Hemodilution Combined with Aprotinin on Allogeneic Blood Transfusion Requirements in Cardiac Surgery
Authors: Höhn Laurent , Schweizer Alexandre , Licker Marc , Morel Denis R. 
Published: November 2003

Background
The efficacy of acute normovolemic hemodilution (ANH) in decreasing allogeneic blood requirements remains controversial during cardiac surgery.

Methods
In a prospective, randomized study, 80 adult cardiac surgical patients with normal cardiac function and no high risk of ischemic complications were subjected either to ANH, from a mean hematocrit of 43% to 28%, or to a control group. Aprotinin and intraoperative blood cell salvage were used in both groups. Blood (autologous or allogeneic) was transfused when the hematocrit was less than 17% during cardiopulmonary bypass, less than 25% after cardiopulmonary bypass, or whenever clinically indicated.

Results
The amount of whole blood collected during ANH ranged from 10 to 40% of the patients' estimated blood volume. Intraoperative and postoperative blood losses were not different between control and ANH patients (total blood loss, control: 1,411 +/- 570 ml, n = 41; ANH: 1,326 +/- 509 ml, n = 36). Allogeneic blood was given in 29% of control patients (median, 2; range, 1-3 units of packed erythrocytes) and in 33% of ANH patients (median, 2; range, 1-5 units of packed erythrocytes; P = 0.219). Preoperative and postoperative platelet count, prothrombin time, and partial thromboplastin time were similar between groups. Perioperative morbidity and mortality were not different in both groups, and similar hematocrit values were observed at hospital discharge (33.7 +/- 3.9% in the control group and 32.6 +/- 3.7% in the ANH group; nonsignificant)

Conclusions
Hemodilution is not an effective means to lower the risk of allogeneic blood transfusion in elective cardiac surgical patients with normal cardiac function and in the absence of high risk for coronary ischemia, provided standard intraoperative cell saving and high-dose aprotinin are used.
Electroacupuncture Prophylaxis of Postoperative Nausea and Vomiting following Pediatric Tonsillectomy with or without Adenoidectomy
Authors: Rusy Lynn M. , Hoffman George M. , Weisman Steven J. 
Published: November 2003

Background
Electrical stimulation of acupuncture point P6 reduces the incidence of postoperative nausea or vomiting (PONV) in adult patients. However, acupressure, laser stimulation of P6, and acupuncture during anesthesia have not been effective for reducing PONV in the pediatric population. The authors studied the effect of electrical P6 acupuncture in awake pediatric patients who had undergone surgery associated with a high incidence of PONV.

Methods
Patients aged 4-18 yr undergoing tonsillectomy with or without adenoidectomy were randomly assigned to acupuncture, sham acupuncture, or control groups. Acupuncture needles at P6 and a neutral point were placed while patients were anesthetized, and low-frequency electrical stimulation was applied to these points for 20 min in the recovery room while the patients were awake (P6 Acu group). This treatment was compared with sham needles along the arm at acupuncture points not associated with antiemesis (sham group) and a no-needle control group. The arms were wrapped to prevent identification of treatment group, and anesthetic, analgesic, and surgical technique were standardized. Assessed outcomes were occurrence of nausea, occurrence and number of episodes of vomiting, time to vomiting, and use of antiemetic rescue medication.

Results
One hundred twenty patients were enrolled in the study, 40 per group. There were no differences in age, weight, sex, or opioid administration between groups. The PONV incidence was significantly lower with P6 acupuncture (25 of 40 or 63%; odds ratio, 0.135; number needed to treat, 3.3; P < 0.001) compared with controls (37 of 40 or 93%). Sham puncture had no effect on PONV (35 of 40 or 88%; P = not significant). Occurrence of nausea was significantly less in P6 Acu (24 of 40 or 60%; odds ratio, 0.121; P < 0.01), but not in the sham group (34 of 40 or 85%) compared with the control group (37 of 40 or 93%). Vomiting occurred in 25 of 40 or 63% in P6 Acu; 35 of 40 or 88% in the sham group, and 31 in 40 or 78% in the control group (P = not significant). Patients receiving sham puncture vomited significantly earlier (P < 0.02) and needed more rescue treatment (33 of 40 or 83%; odds ratio, 3.48; P < 0.02) compared with P6 Acu (23 of 40 or 58%) and the control group (24 of 40 or 60%).

Conclusions
Perioperative P6 electroacupuncture in awake patients significantly reduced the occurrence of nausea compared with the sham and control groups, but it did not significantly reduce the incidence or number of episodes of emesis or the use of rescue antiemetics. Sham acupuncture may exacerbate the severity but not the incidence of emesis. The efficacy of P6 acupuncture for PONV prevention is similar to commonly used pharmacotherapies. Its appropriate role in prevention and treatment of PONV requires further study.
Can Assessment for Obstructive Sleep Apnea Help Predict Postadenotonsillectomy Respiratory Complications?
Authors: Wilson Kerryn , Lakheeram Indrani , Morielli Angie , Brouillette Robert , Brown Karen 
Published: November 2003

Background
The aim of this study was to determine the frequency and type of respiratory complications after adenotonsillectomy in children. A second aim was to assess the ability of preoperative sleep studies to identify children at risk for respiratory complications.

Methods
Children referred for sleep studies between 1992 and 1998, who underwent adenotonsillectomy within 6 months of the preoperative study, were reviewed. The study focused on two variables: the obstructive apnea and hypopnea index and the oxygen saturation nadir. Medical charts were reviewed for postoperative respiratory complications.

Results
Three hundred forty-nine children were referred for sleep studies, and 163 met the inclusion criteria. Thirty-four children (21%) had postoperative respiratory complications requiring a medical intervention. Children experiencing respiratory complications were younger (aged < 2 yr; adjusted odds ratio, 4.3; 95% confidence interval, 1.7-11) and had an associated medical condition (odds ratio, 3; 95% confidence interval, 1.4-6.5). A preoperative obstructive apnea and hypopnea index of 5 or more events per hour increased the chance of postoperative respiratory complications (odds ratio, 7.2; 95% confidence interval, 2.7-19.3), as did a preoperative oxygen saturation nadir of 80% or less (odds ratio, 6.4; 95% confidence interval, 2.8-14.5). A preoperative oxygen saturation nadir of 80% or less had a likelihood ratio of 3.1, increasing the probability of postoperative respiratory complications from 20 to 50%.

Conclusions
The data suggest, but do not prove, that preoperative nocturnal oximetry could be a useful preoperative test to identify children who are at increased risk for postoperative respiratory complications.
Effect of the α2-Agonist Dexmedetomidine on Cerebral Neurotransmitter Concentrations during Cerebral Ischemia in Rats
Authors: Engelhard Kristin , Werner Christian , Kaspar Susanne , Möllenberg Oliver , Blobner Manfred , Bachl Monika , Kochs Eberhard 
Published: November 2003

Background
This study investigates whether neuroprotection seen with dexmedetomidine is associated with suppression of peripheral or central sympathetic tone.

Methods
Thirty fasted male Sprague-Dawley rats were intubated and ventilated with isoflurane and N2O/O2 (fraction of inspired oxygen = 0.33). Catheters were inserted into the right femoral artery and vein and into the right jugular vein. Cerebral blood flow was measured using laser Doppler flowmetry. Bilateral microdialysis probes were placed into the cortex and the dorsal hippocampus. At the end of preparation, the administration of isoflurane was replaced by fentanyl (bolus: 10 microg/kg; infusion: 25 microg x kg(-1) x h(-1)). Animals were randomly assigned to one of the following groups: group 1 (n = 10): control animals; group 2 (n = 10): 100 microg/kg dexmedetomidine administered intraperitoneally 30 min before ischemia; group 3 (n = 10): sham-operated rats. Ischemia (30 min) was produced by unilateral carotid artery occlusion plus hemorrhagic hypotension to a mean arterial blood pressure of 30-35 mmHg to reduce ipsilateral cerebral blood flow by 70%. Pericranial temperature, arterial blood gases, and pH were maintained constant. Cerebral catecholamine and glutamate concentrations and plasma catecholamine concentrations were analyzed using high-performance liquid chromatography.

Results
During ischemia, dexmedetomidine suppressed circulating norepinephrine concentrations by 95% compared with control animals. In contrast, brain norepinephrine and glutamate concentrations were increased irrespective of dexmedetomidine infusion before ischemia.

Conclusions
The current data show that the increase of circulating catecholamine concentrations during cerebral ischemia was suppressed with dexmedetomidine. In contrast, dexmedetomidine does not suppress elevation in brain norepinephrine and glutamate concentration associated with cerebral ischemia. This suggests that the neuroprotective effects of dexmedetomidine are not related to inhibition of presynaptic norepinephrine or glutamate release in the brain.
Recombinant Human Transgenic Antithrombin in Cardiac Surgery
Authors: Levy Jerrold H. , Despotis George J. , Szlam Fania , Olson Peter , Meeker David , Weisinger Andrew 
Published: November 2003

Background
Acquired antithrombin III (AT) deficiency may render heparin less effective during cardiac surgery and cardiopulmonary bypass (CPB). The authors examined the pharmacodynamics and optimal dose of recombinant human AT (rh-AT) needed to maintain normal AT activity during CPB, optimize the anticoagulant response to heparin, and attenuate excessive activation of the hemostatic system in patients undergoing coronary artery bypass grafting.

Methods
Thirty-six patients scheduled to undergo elective primary coronary artery bypass grafting and who had received heparin for 12 h or more before surgery were enrolled in the study. Ten cohorts of three patients each received rh-AT in doses of 10, 25, 50, 75, 100, 125, 175, or 200 U/kg, a cohort of six patients received 150 U/kg of rh-AT, and a control group of six patients received placebo.

Results
Antithrombin III activity exceeded 600 U/dl before CPB at the highest dose (200 U/kg). Doses of 75 U/kg rh-AT normalized AT activity to 100 U/dl during CPB. Activated clotting times during CPB were significantly (P < 0.0001) greater in patients who received rh-AT (844 +/- 191 s) compared with placebo patients (531 +/- 180 s). Significant (P = 0.001) inverse relations were observed between rh-AT dose and both fibrin monomer (r = -0.51) and D-dimer (r = -0.51) concentrations. No appreciable adverse events were observed with any rh-AT doses used in the study.

Conclusions
Supplementation of native AT with transgenically produced protein (rh-AT) in cardiac surgical patients was well tolerated and resulted in higher activated clotting times during CPB and decreased levels of fibrin monomer and D-dimer.
Utility of Whole Blood Hemostatometry Using the Clot Signature Analyzer®for Assessment of Hemostasis in Cardiac Surgery
Authors: Faraday Nauder , Guallar Eliseo , Sera Valerie A. , Bolton Everlie D. , Scharpf Robert B. , Cartarius Ann M. , Emery Kathryn , Concord Julia , Kickler Thomas S. 
Published: November 2003

Background
A hemostatic monitor capable of rapid, accurate detection of clinical coagulopathy within the operating room could improve management of bleeding after cardiopulmonary bypass (CPB). The Clot Signature Analyzer is a hemostatometer that measures global hemostasis in whole blood. The authors hypothesized that point-of-care hemostatometry could detect a clinical coagulopathic state in cardiac surgical patients.

Methods
Fifty-seven adult patients scheduled for a variety of elective cardiac surgical procedures were studied. Anesthesia, CPB, heparin anticoagulation, protamine reversal, and transfusion for post-CPB bleeding were all managed by standardized protocol. Clinical coagulopathy was defined by the need for platelet or fresh frozen plasma transfusion. The Clot Signature Analyzer collagen-induced thrombus formation (CITF) assay measured platelet-mediated hemostasis in vitro. The activated clotting time, platelet count, prothrombin time, activated partial thromboplastin time, and fibrinogen concentration were also measured.

Results
The postprotamine CITF was greater in patients who required hemostatic transfusion than in those who did not (17.6 +/- 8.0 min vs. 10.5 +/- 5.7 min, respectively; P < 0.01). Postprotamine CITF values were highly correlated with platelet and fresh frozen plasma transfusion (Spearman r = 0.50, P < 0.001 and r = 0.40, P < 0.005, respectively). Receiver operator characteristic curves showed a highly significant relation between the postprotamine CITF and intraoperative platelet and fresh frozen plasma transfusion (area under the curve, 0.78-0.81, P < 0.005) with 60-80% sensitivity, specificity, positive and negative predictive values at cutoffs of 12-14 min. Logistic regression demonstrated that the CITF was independently predictive of post-CPB hemostatic transfusion, but standard hemostatic assays were not.

Conclusions
The Clot Signature Analyzer CITF detects a clinical coagulopathic state after CPB and is independently predictive of the need for hemostatic transfusion. Hemostatometry has potential utility for monitoring hemostasis in cardiac surgery.
Ketamine Suppresses Platelet Aggregation Possibly by Suppressed Inositol Triphosphate Formation and Subsequent Suppression of Cytosolic Calcium Increase
Authors: Nakagawa Takefumi , Hirakata Hideo , Sato Masami , Nakamura Kumi , Hatano Yoshio , Nakamura Takashi , Fukuda Kazuhiko 
Published: November 2003

Background
Ketamine has been shown to suppress platelet aggregation, but its mechanisms of action have not been defined. The purpose of the current study is to clarify the effects of ketamine on human platelet aggregation and to elucidate the underlying mechanisms of its action.

Methods
Platelet aggregation was measured using an eight-channel aggregometer, and cytosolic free calcium concentration was measured in Fura-2/AM-loaded platelets using a fluorometer. Inositol 1,4,5-triphosphate (IP3) was measured with use of a commercially available IP3 assay kit. To estimate thromboxane A2 (TXA2) receptor binding affinity and expression, Scatchard analysis was performed using [3H]S145, a specific TXA2 receptor antagonist. TXA2 agonist binding assay was also performed. The membrane-bound guanosine 5'-triphosphatase activity was determined using [gamma-32P]guanosine triphosphate by liquid scintillation analyzer.

Results
Ketamine (500 microm) suppressed aggregation induced by adenosine diphosphate (0.5 microm), epinephrine (1 microm), (+)-9,11-epithia-11,12-methano-TXA2 (STA2) (0.5 microm), and thrombin (0.02 U/ml) to 39.1 +/- 30.9, 46.3 +/- 4.3, -2.0 +/- 16.8, and 86.6 +/- 1.4% of zero-control, respectively. Ketamine (250 microm-1 mm) also suppressed thrombin- and STA2-induced cytosolic free calcium concentration increase dose dependently. Although ketamine (2 mm) had no effect on TXA2 receptor expression and its binding affinity, it (1 mm) suppressed intracellular peak IP3 concentrations induced by thrombin and STA2 from 6.60 +/- 1.82 and 4.39 +/- 2.41 to 2.41 +/- 0.98 and 1.90 +/- 0.86 pmol/109 platelets, respectively, and it suppressed guanosine triphosphate hydrolysis induced by thrombin (0.02 units/ml) and STA2 (0.5 microm) to 50.3 +/- 3.2 and 67.5 +/- 5.5% versus zero-control, respectively.

Conclusion
Ketamine inhibits human platelet aggregation possibly by suppressed IP3 formation and subsequent suppression of cytosolic free calcium concentration. The site of action of ketamine is neither TXA2 nor thrombin binding sites but possibly receptor-coupled mechanisms, including G-protein.