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B J Anderson

Publications and source records attributed to B J Anderson.

At least 37 records · Page 2Linked to original sources
PubMed2001

Acetaminophen analgesia in children: placebo effect and pain resolution after tonsillectomy.

BACKGROUND: Pharmacodynamic models of acetaminophen analgesia in children have not explored the efficacy of single oral doses greater than 40 mg/kg. METHODS: Children aged 9.0 +/- 3.0 years (+/- SD) and weight 37.9+/- 16.6 kg undergoing outpatient tonsillectomy were randomised to receive acetaminophen elixir 40 mg/kg (n = 12). high dose acetaminophen elixir 100 mg/kg (n =20) or placebo (n=30) 0.5 -1 h preoperatively. No other analgesics were given. Individual acetaminophen serum concentrations and pain scores [visual analogue scale (VAS) 0-10] were measured over a 4-8 h postoperative period. These data were pooled with data from a previous study investigating acetaminophen pharmacodynamics (n = 120) and analysed using a non-linear mixed effect model. Placebo effects and drug effects were modelled using effect-site concentration models. RESULTS: A one-compartment model with first-order input, lag time and first-order elimination was used to describe the population pharmacokinetics of acetaminophen. Pharmacokinetic parameter estimates were similar to those previously described. Pharmacodynamic population parameter estimates [population variability coefficient of variation (CV)] for a maximum analgesic effect (Emax) model, in which the greatest possible pain relief (VAS 0-10) equates to an Emax of 10, were Emax 5.17 (64%) and 50% effective concentration 9.98 mg/l (107%). The equilibration half-life (t(eq)) of the analgesic effect compartment was 53 min (217%). A placebo drug model for the effects of placebo response had a t(eq) of 1.96 h (40%), an elimination half-life of 2.06 h (50%) and a potency of 1.54 pain relief units (24%). CONCLUSIONS: High dose acetaminophen (100 mg/kg) was no more effective than 40 mg/kg and was associated with increased nausea and vomiting. A target effect compartment concentration of 10 mg/l is expected to produce a pain reduction of 2.6 units. The placebo model accounted for a maximum pain reduction of 5.6 units at 3 h. The combination of placebo effect and preoperative acetaminophen 40 mg/kg results in pain scores below 4 units for 5 h postoperatively.

Acetaminophen↗
PubMed2001

Valvular heart operation in patients with previous mediastinal radiation therapy.

BACKGROUND: The outcome of valvular heart operations in patients with previous mediastinal radiation therapy was studied. METHODS: This is a single center retrospective study of 60 patients (37 females, 23 males) with a mean age of 62 +/- 15 years (28 to 88 years old) operated on from January 1976 to December 1998. Valvular heart operations performed included aortic valve replacements (n = 26), mitral valve procedures (n = 16), tricuspid valve procedures (n = 6), and multiple valve procedures (n = 12). A total of 264 clinical, hemodynamic, electrocardiographic and echocardiographic variables were analyzed. RESULTS: Total follow-up was 199 patient-years with a mean of 3.3 +/- 3.1 years and a range of 0 to 12.4 years old. Early mortality was 7 patients (12%). Early mortality in patients with constrictive pericarditis was 40% (4 of 10) compared with 6% (3 of 50) in patients without constrictive pericarditis. By univariate analysis, early mortality was associated with constrictive pericarditis (p = 0.011), reduced preoperative ejection fraction (p = 0.015), and longer cardiopulmonary bypass times (p = 0.037). A total of 14 patients (23%) required permanent pacemaker placement before (n = 7), during (n = 1), or early (n = 6) after valvular heart operations. There were 19 late deaths (malignancies, 7; heart failures, 5; other cardiac, 4; and other noncardiac, 3). Overall survival and freedom from late cardiac death and cardiac reoperation at 5 years for hospital survivors were 66% +/- 8%, 82% +/- 7%, and 93% +/- 4%, respectively. By univariate analysis, late cardiac death was associated with low ejection fraction (p = 0.002), New York Heart Association (NYHA) functional class IV (p = 0.004), preoperative congestive heart failure (p = 0.02), and preoperative atrial fibrillation (p = 0.038). Eighty-five percent of the discharged patients were in NYHA functional class I or II at follow-up. CONCLUSIONS: Early results of valve replacement after mediastinal radiation therapy were good except in the presence of constrictive pericarditis. Long-term outcome was limited by malignancy and heart failure. Early surgical intervention is recommended before the development of risk factors for late death, namely, severe symptoms, left ventricular dysfunction, and atrial fibrillation.

Adult↗
PubMed2001

Impact of an antiemetic protocol on postoperative nausea and vomiting in children.

The objective of the study was to demonstrate a decreased incidence of postoperative nausea and vomiting (PONV) in children through the use of an antiemetic protocol. PONV was recorded in children (1.5-15 years) after inpatient surgery under general anaesthesia in a prospective, interview based survey. Group 1 consisted of children having surgery 1 month before the introduction of a formalized antiemetic protocol and group 2, 2 months after its introduction. Data were collected over a 1-month period in each group. Outcome measures of nausea, emesis, antiemetic requirement and patient satisfaction were monitored for the first 24-h postoperative period. There were 272 children enrolled: 138 in group 1 and 134 in group 2. There was a difference between the two groups for gender (P=0.03), type of surgery (P=0.017), perioperative opioid (P=0.003) and perioperative antiemetic use (P=0.024). However, multivariate analysis did not demonstrate an impact on outcome from these factors. The incidence of postoperative nausea (PON) and postoperative vomiting (POV) following the introduction of the protocol was 36% and 34%, respectively. Moderate to severe nausea was decreased after introduction of the protocol (18% versus 9%, P=0.028) but moderate to severe vomiting failed to reach significance (19% versus 11%, P=0.078). The proportion of children who had repeated nausea decreased after the introduction of the protocol (17% versus 8%, P=0.02) but repeated episodes of vomiting remained unchanged (19% versus 14%). This was attributed to a significant increase in antiemetic prescribing by protocol in group 2 (10% versus 59%, P < 0.001). Patient satisfaction was high in both groups (85% versus 90%). The introduction of a postoperative antiemetic protocol improved prescribing frequency. This resulted in a decreased incidence of moderate to severe PON and a reduction in the number of patients with repeated nausea.

Adolescent↗
PubMed2001

Predictors of glycemic control and short-term adverse outcomes in youth with type 1 diabetes.

OBJECTIVES: To examine predictors of glycemic control and to assess how glycemic control affects the incidence of short-term adverse outcomes in a pediatric population with type 1 diabetes. STUDY DESIGN: Three hundred youth, aged 7 to 16 years, with type 1 diabetes who were receiving diabetes specialty care were followed up prospectively for 1 year. Treatment plans and frequency of adverse outcomes were ascertained by questionnaires and medical record review. Incidence rates of adverse outcomes were compared among 3 strata of the population, representing tertiles of baseline glycosylated hemoglobin (HbA1c). RESULTS: Blood glucose monitoring frequency was the sole modifiable predictor of HbA1c (P <.0001). Overall incidence rate of hospitalization was 13 per 100 person-years, more than 3 times the rate in the general pediatric population and significantly higher in the upper HbA1c tertile compared with the other strata (P =.001). Rate of emergency department use was 29 per 100 person-years and did not differ significantly among tertiles. Incidence of severe hypoglycemia was 62 per 100 person-years and notably high even in those with poorest glycemic control. CONCLUSION: Despite improvements in diabetes care, the incidence of short-term adverse events in children with type 1 diabetes remains high, particularly in those with poorest glycemic control.

Adolescent↗
PubMed2001

Children with diabetes mellitus and family functioning: translating research into practice.

The specific challenges of living with diabetes mellitus (DM) which the child and parent must confront at each developmental stage are identified from infancy through adolescence. This discussion is divided into four developmental stages: 1) DM in infancy (0-2 years of age); 2) DM in toddlers and preschoolers (2-5 years); 3) DM in the school-age child (6-11 years); and 4) DM during early- to mid-adolescence (12-16 years). The central milestones of normal psychosocial development are reviewed and a summary is provided of recent research at each developmental stage with an emphasis on clinical implications for pediatric diabetes care teams.

Child↗
PubMed2001

Adverse drinking consequences among alcohol abusing intravenous drug users.

BACKGROUND: Heavy alcohol use is common among out-of-treatment injection drug users (IDUs); however, the relationship between alcohol and drug use behaviors in codependent populations is not well understood. Our specific objectives were (1) to describe the psychometric properties of the Drinker Inventory of Consequences (DrInC) in a sample of active IDUs, and (2) to compare DrInC scores of active IDUs with those reported for the alcohol treatment seeking sample on which the instrument was developed. METHODS: Interview data were collected from 187 active IDUs who scored positively (> or = 8) on the Alcohol Use Disorders Identification Test, who were recruited from a Providence, RI, needle exchange program (1998-1999). DrInC total and subscale scores for the 159 (85%) participants who met DSM-IV criteria for alcohol abuse/dependence were analyzed. Six-month follow-up data were used to estimate test-retest reliability. RESULTS: The DrInC total scale exhibited high internal consistency and test-retest reliability. With the exception of adverse physical consequences, reliability estimates for DrInC subscales were good to very good. These data indicate higher subscale redundancy than reported for the development sample. Active IDUs had significantly higher adverse impulse control consequences than the alcohol treatment seeking population on which the instrument was developed. CONCLUSIONS: The DrInC exhibits desirable psychometric properties for assessing adverse drinking consequences in active IDU populations. IDUs who met DSM-IV criteria for alcohol abuse/dependence reported overall levels of adverse drinking consequences comparable with non-IDU alcohol treatment populations but were more likely to exhibit adverse impulse control consequences.

Adult↗
PubMed2000

Exercise influences spatial learning in the radial arm maze.

Previous studies indicate that the hippocampus is active during exercise, and that neurotrophin expression, receptor density, and survival of dentate gyrus granule cells in the hippocampus can be modified by moderate voluntary exercise. The present study was designed to test the consequences of voluntary exercise on a hippocampal-related behavior. Exercising and control rats were tested on the standard and delayed nonmatch-to-position (DNMTP) version of the eight-arm radial maze, both of which are sensitive to hippocampal damage. Voluntarily exercising rats ran in running wheels attached to their home cage for 7 weeks prior to and throughout testing, and took 30% fewer trials to acquire criterion performance than sedentary controls. Both groups spent the same average time per arm. Once the eight-arm maze had been learned to criterion, group differences were not apparent. Exercise can facilitate acquisition of a hippocampal-related spatial learning task, but does not affect performance following acquisition. Further work will be necessary to link these effects to hippocampal-related variables shown to be influenced by exercise.

Analysis of Variance↗
PubMed2000

The ratio of striatal D1 to muscarinic receptors changes in aging rats housed in an enriched environment.

The enriched environment (EC) causes morphological plasticity in striatal cells that express D1 and D2 receptors. We used radioligand binding assays to examine whether EC produces plasticity in striatal receptor density and receptor density ratios. After 30 days of EC, 2-year-old rats had a higher ratio of D1 to muscarinic receptors in striatum relative to singly housed rats. Assays also showed trends for a greater ratio of D1 to cannabinoid receptors and a greater density of D1 receptors in striatum after EC. D2 receptor density was unaffected by the EC condition.

Aging↗
PubMed2000

Ley/H: an endothelial-selective, cytokine-inducible, angiogenic mediator.

Endothelial cells (ECs) are key participants in angiogenic processes that characterize tumor growth, wound repair, and inflammatory diseases, such as human rheumatoid arthritis (RA). We and others have shown that EC molecules, such as soluble E-selectin, mediate angiogenesis. Here we describe an EC molecule, Lewisy-6/H-5-2 glycoconjugate (Ley/H), that shares some structural features with the soluble E-selectin ligand, sialyl Lewisx (sialyl Lex). One of the main previously recognized functions of Lewisy is as a blood group glycoconjugate. Here we show that Ley/H is rapidly cytokine inducible, up-regulated in RA synovial tissue, where it is cell-bound, and up-regulated in the soluble form in angiogenic RA compared with nonangiogenic osteoarthritic joint fluid. Soluble Ley/H also has a novel function, for it is a potent angiogenic mediator in both in vitro and in vivo bioassays. These results suggest a novel paradigm of soluble blood group Ags as mediators of angiogenic responses and suggest new targets for therapy of diseases, such as RA, that are characterized by persistent neovascularization.

ABO Blood-Group System↗
PubMed2000

Comparing the predictive validity of DUI risk screening instruments: development of validation standards.

AIMS: This study compares the predictive efficacy of driving under the influence (DUI) screening instruments validated in previous studies, illustrates how variations in base rates of failure and selection ratios affect conclusions concerning the efficacy of different instruments, and develops evaluation standards to ensure valid comparisons of risk prediction instruments. DESIGN: The study: (1) examines a sample of 4815 DUI offenders to illustrate how variations in base rates of failure and selection ratios affect traditional measures of predictive efficacy, (2) uses such measures to compare the predictive efficacy of 10 instruments validated in previous studies, and (3) demonstrates the use of a measure of predictive efficacy which is relatively insensitive to the aforementioned variations. FINDINGS: While three instruments examined at specific cut-points consistently ranked highest on several measures of predictive efficacy, use of different evaluation standards produced substantively different conclusions regarding the efficacy of different instruments. Based on the analyses, standards for validation of risk prediction instruments were developed. CONCLUSIONS: The findings illustrate how failure to use equivalent standards have led to erroneous conclusions concerning the relative predictive efficacy of different risk prediction instruments. The standards developed in this study should facilitate equivalent comparisons of the predictive efficacy of risk prediction instruments.

Alcohol Drinking↗
PubMed2000

A model for size and age changes in the pharmacokinetics of paracetamol in neonates, infants and children.

AIMS: The aims of this study were to describe paracetamol pharmacokinetics in neonates and infants. METHODS: Infants in their first 3 months of life (n = 30) were randomised to sequentially receive one of three paracetamol formulations (dose 30-40 mg kg-1) over a 2 day period. The formulations were (a) elixir, (b) glycogelatin capsule suppository and (c) triglyceride base suppository. Approximately six blood samples were taken after each dose over the subsequent 10-16 h. Data were analysed using a nonlinear mixed effect model. These neonatal and infant data were then included with data from four published studies of paracetamol pharmacokinetics (n = 221) and age-related pharmacokinetic changes investigated. RESULTS: Population pharmacokinetic parameter estimates and their coefficients of variation (CV%) for a one compartment model with first order input, lag time and first order elimination were volume of distribution 69.9 (18%) l and clearance 13.0 (41%) l h-1 (standardized to a 70 kg person). The volume of distribution decreased exponentially with a half-life of 1.9 days from 120 l 70 kg-1 at birth to 69.9 l 70 kg-1 by 14 days. Clearance increased from birth (4.9 l h-1 70 kg-1) with a half-life of 3.25 months to reach 12.4 l h-1 70 kg-1 by 12 months. The absorption half-life (tabs) for the oral preparation was 0.13 (154%) h with a lag time (tlag) of 0.39 h (31%). Absorption parameters for the triglyceride base and capsule suppositories were tabs 1.34 (90%) h, tlag 0.14 h (31%) and tabs 0.65 (63%) h, tlag 0.54 h (31%), respectively. The tabs for elixir and capsule suppository in children under 3 months were 3.68 and 1.51 times greater than children over 3 months. The relative bioavailability of rectal formulations compared with elixir were 0.67 (30%) and 0.61 (23%) for the triglyceride base and capsule suppositories, respectively. CONCLUSIONS: Total body clearance of paracetamol at birth is 62% and volume of distribution 174% that of older children. A target concentration above 10 mg l-1 in approximately 50% subjects can be achieved by a dose from 45 mg kg-1 day-1 at birth and up to 90 mg kg-1 day-1 in 5-year-old children. A reduced dose of 75 mg kg-1 day-1 in an 8-year-old child is sufficient because clearance is a nonlinear function of weight.

Acetaminophen↗
PubMed2000

Investigations using logistic regression models on the effect of the LMA on morphine induced vomiting after tonsillectomy.

The effect of intraoperative airway management on postoperative vomiting after tonsillectomy is unknown. Logistic regression was used in a retrospective study to investigate the effect of the laryngeal mask airway (LMA) on a morphine dose-vomiting response curve. Charts were reviewed in 351 children in whom the airway was managed with either a LMA (n=177) or a tracheal tube (n=174). A mean perioperative morphine dose of 0.10 mg.kg(-1) (SD 0.09) was used in 248 children and a further 103 children were given no opioid. One hundred and eighteen of these 248 children vomited (47.6%) compared to 14 of 103 children given no morphine (13.6%). The probability of vomiting was related to morphine dose using logistic regression with both a linear and an E(max) model. Both the calibration (Hosmer-Lemishow goodness of fit chi-squared test lambda(2), P=0.81) and discrimination (area under the receiver operating characteristic plot, AUC ROC=0.67) of the E(max) model were better than the linear model (lambda(2), P=0.49; AUC ROC=0.64). Pharmacodynamic parameter estimates for the Emax model were P(0) (the baseline probability of vomiting) 0.139, P(max) (the maximal probability of vomiting due to morphine) 0.96, ED(50) (morphine dose that induces an effect equivalent to 50% of the logit P(max)) 0.09 mg.kg-1. The probability of vomiting was 50% after morphine 0.125 mg.kg-1. The use of the LMA had no effect on this dose-response curve. A covariate analysis investigating propofol for induction or isoflurane for the intraoperative maintenance of anaesthesia, however, showed that both drugs shifted the curve to the right. The probability of vomiting was 50% after morphine 0.17 mg.kg(-1) and 0.21 mg.kg(-1) for the isoflurane and propofol use curves, respectively. The concomitant use of propofol and isoflurane, but not the use of the LMA, decreases the probability of vomiting due to morphine.

Adolescent↗
PubMed2000

The dose-effect relationship for morphine and vomiting after day-stay tonsillectomy in children.

A dose-response curve for intravenous morphine and vomiting was investigated in children having day-stay tonsillectomy. A retrospective chart review was performed for the 164 children fulfilling the inclusion criteria. Morphine (mean 0.09 mg/kg SD 0.05) was used in 108 children in the perioperative period and a further 56 children were given no opioid. Fifty-five of these 164 children vomited and 20 children required an overnight stay in hospital because of vomiting. The probability of vomiting or overnight stay in hospital was related to morphine dose (by logistic regression). The overall probability of vomiting after morphine 0.1 mg/kg was 50% and the probability of admission for vomiting with this dose was 10%. Pharmacodynamic parameter estimates for postoperative vomiting were P0 (the baseline probability of vomiting, with no opioid) 0.115, Pmax (the maximal probability of vomiting due to morphine) 0.997, ED50 (morphine dose that induces an effect equivalent to 50% of the logit Pmax) 0.18 mg/kg. Parameter estimates for overnight stay because of vomiting after morphine administration were P0 0.038, Pmax 0.999, ED50 0.369 mg/kg. Satisfactory postoperative analgesia in children has been reported with morphine 0.05 to 0.15 mg/kg. Doses above 0.1 mg/kg are associated with a greater than 50% incidence of vomiting. Our data suggests that lower doses of morphine are associated with a decreased incidence of emesis after tonsillectomy in children.

Adolescent↗
PubMed1999

Surgical patent foramen ovale closure for prevention of paradoxical embolism-related cerebrovascular ischemic events.

BACKGROUND: The role of surgical closure of patent foramen ovale (PFO) for cerebral infarction (CI) or transient ischemic attack (TIA) resulting from paradoxical embolism is unclear, and its effect on recurrence is unknown. Our objective was to determine the outcome of surgical closure of PFO in patients with a prior ischemic neurological event, define the rate of CI or TIA recurrence after PFO closure, and identify risk factors for these recurrences. METHODS AND RESULTS: We retrospectively analyzed 91 patients (58 men, 33 women) with >/=1 previous cerebrovascular ischemic events who underwent surgical PFO closure between April 1982 and March 1998. The presence of a PFO with a right-to-left shunt was confirmed with transesophageal echocardiography. Mean age was 44.2+/-12.2 years. The index event was a CI in 59 and a TIA in 32; a Valsalva-like episode preceded the event in 15 patients. Deep venous thrombosis was documented in 9 patients, and a hypercoagulable state was identified in 10. Surgical closure was performed with extracorporeal circulation by either direct suture (n=82) or patch closure (n=9). Limited incisions were used in 18.7% of patients. There was no operative mortality. Morbidity included transient atrial fibrillation (n=11), pericardial drainage for effusion (n=4), exploration for bleeding (n=3), and superficial wound infection (n=1). Follow-up totaled 176.3 patient-years, and mean follow-up was 2.0 years. No one had a CI, and 8 had a TIA during follow-up, with 1 caused by temporal arteritis. Transesophageal echocardiography demonstrated all closures to be intact in these patients. The overall freedom from TIA recurrence during follow-up was 92.5+/-3.2% at 1 year and 83.4+/-6.0% at 4 years. Having multiple neurological events before PFO closure was the only significant risk factor for TIA or CI recurrence after closure by univariate analysis (P=0.05); the small number of post-PFO closure cerebral ischemic events precluded multivariate analysis. CONCLUSIONS: Surgical closure of PFO can be performed with minimal morbidity and mortality. PFO closure may decrease the risk of recurrent stroke or TIA and may avoid lifelong anticoagulation in the young adult if there is no other indication. Recurrent cerebrovascular ischemic events after surgery should prompt further evaluation to identify causes other than paradoxical embolism.

Adult↗
PubMed1999

Predicting concentrations in children presenting with acetaminophen overdose.

OBJECTIVE: To predict serum concentrations to evaluate and improve guidelines for the treatment of children (1 to 5 years) with accidental ingestion of acetaminophen elixir. METHODS: Acetaminophen concentrations for 1000 children were simulated with pharmacokinetic parameters and their expected variability. The distribution of concentrations arising from a 300 mg/kg dose at different age groups was predicted. These predictions were validated by comparison with concentrations obtained at 4 hours from 121 children with accidental ingestion of acetaminophen elixir. RESULTS: No child who presented with overdose had a concentration in the probable risk area of the Rumack-Matthew toxicity nomogram. Enteral charcoal administered 98 minutes (SD 44) after ingestion had no effect on serum concentrations. The simulation predicted that an acetaminophen dose of 300 mg/kg would result in concentrations of 32 to 208 mg/L (95% CI) at 4 hours after ingestion. The maximum concentration occurred before 2 hours in 95% of simulated children. CONCLUSION: Children (1 to 5 years) with reported ingestion of >250 mg/kg acetaminophen elixir should have serum concentrations measured at 2 hours after ingestion rather than at the 4-hour time point recommended in adults. This can be expected to speed discharge and reduce anxiety. The use of enteral charcoal is unlikely to enhance acetaminophen elimination, unless it is given within an hour of acetaminophen ingestion.

Acetaminophen↗
PubMed1999

Outcome of valve repair and the Cox maze procedure for mitral regurgitation and associated atrial fibrillation.

OBJECTIVE: The objective was to determine whether the Cox maze procedure provides adjunctive benefit in patients with atrial fibrillation undergoing mitral valve repair. METHODS: We compared the outcome of 39 patients who had the Cox maze procedure plus mitral valve repair between January 1993 and December 1996 (maze group) with that of 58 patients with preoperative atrial fibrillation who had mitral valve repair during the same interval by the same surgeons (control group). Patients in the 2 cohorts were similar for age, gender, preoperative New York Heart Association class III or IV, and duration of preoperative atrial fibrillation. The control group had a higher incidence of previous heart surgery and coronary artery disease. RESULTS: No operative deaths occurred, and 1 patient in each group required pacemaker implantation after the operation. Duration of cardiopulmonary bypass (122 +/- 40 minutes vs 58 +/- 27 minutes, P <.0001) and hospitalization (12.6 +/- 6.4 vs 9.3 +/- 3.4 days, P <.0025) were prolonged in patients having the Cox maze procedure. Overall, 2-year survival was similar (92% +/- 5% for maze patients and 96% +/- 3% for controls). Freedom from atrial fibrillation in the maze group was 74% +/- 8% 2 years after the operation compared with 27% +/- 7% for the control group (P <.0001). Freedom from stroke or anticoagulant-associated bleeding in the maze group was 100% 2 years after the operation compared with 90% +/- 8% in the control group (P =.04). At most recent follow-up, 82% of maze patients were in normal sinus rhythm (53% in control group). CONCLUSION: The addition of the Cox maze procedure to mitral valve repair is safe and effective for selected patients, and elimination of atrial fibrillation decreased late complications.

Aged↗