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Biomedical subjects

S H Thomas

Publications and source records attributed to S H Thomas.

At least 19 recordsLinked to original sources
PubMed2003

Effect on diagnostic efficiency of analgesia for undifferentiated abdominal pain.

BACKGROUND: The question of whether it is safe to provide analgesia for patients with undifferentiated acute abdominal pain is marked by longstanding controversy over the possible masking of physical findings. The goal of this review is to assess the pertinent studies. METHOD: A Medline search was performed in April 2002, using the terms 'analgesia', 'abdominal pain', 'acute abdomen' and 'morphine'. Other articles were identified using the bibliographies of papers found through Medline. All articles reporting clinical trials of analgesia and its effects on diagnosis or physical examination were reviewed. RESULTS: A total of eight trials (one reported only as an abstract) were identified. Because of significant disparity in trial design, no formal analysis such as meta-analysis was performed. However, detailed review of the trials revealed a striking consistency in results. In no study was there an association between analgesia and diagnostic impairment or dangerous masking of the findings of physical examination. CONCLUSION: The literature addressing early pain relief for abdominal pain is characterized by weaknesses, but there is a common theme suggesting that analgesia is safe. Pending further research, which should address some of the shortcomings of extant studies, a practice of judicious provision of analgesia appears safe, reasonable and in the best interests of patients in pain.

Abdominal Pain↗
PubMed2000

Reduction in incidence of severe paracetamol poisoning.

We report substantial reductions in the frequency of severe paracetamol hepatotoxicity locally and nationally after legislative limitations on its sale. These reductions were not explained by changes in referral patterns or use of N-acetylcysteine.

Acetaminophen↗
PubMed2000

QTc-interval abnormalities and psychotropic drug therapy in psychiatric patients.

BACKGROUND: Sudden unexplained death in psychiatric patients may be due to drug-induced arrhythmia, of which lengthening of the rate-corrected QT interval (QTc) on the electrocardiogram is a predictive marker. We estimated the point prevalence of QTc lengthening in psychiatric patients and the effects of various psychotropic drugs. METHODS: Electrocardiograms were obtained from 101 healthy reference individuals and 495 psychiatric patients in various inpatient and community settings and were analysed with a previously validated digitiser technique. Patients with and without QTc lengthening, QTc dispersion, and T-wave abnormality were compared by logistic regression to calculate odds ratios for predictive variables. FINDINGS: Abnormal QTc was defined from the healthy reference group as more than 456 ms and was present in 8% (40 of 495) of patients. Age over 65 years (odds ratio 3.0 [95% CI 1.1-8.3]), use of tricyclic antidepressants (4.4 [1.6-12.1]), thioridazine (5.4 [2.0-13.7]), and droperidol (6.7 [1.8-24.8]) were robust predictors of QTc lengthening, as was antipsychotic dose (high dose 5.3 [1.2-24.4]; very high dose 8.2 [1.5-43.6]). Abnormal QT dispersion or T-wave abnormalities were not significantly associated with antipsychotic treatment, but were associated with lithium therapy. INTERPRETATION: Antipsychotic drugs cause QTc lengthening in a dose-related manner. Risks are substantially higher for thioridazine and droperidol. These drugs may therefore confer an increased risk of drug-induced arrhythmia.

Adolescent↗
PubMed2000

Frequency and costs of laboratory and radiograph repetition in trauma patients undergoing interfacility transfer.

Receiving trauma centers often duplicate laboratory and radiograph testing performed by referring institutions. Our objective was to quantify frequency and costs of this practice. In this prospective study of 104 consecutive interfacility-transported adult trauma patients flown by an emergency medical service to an urban level I center, flight crew noted which labs and radiographs were done at referring hospitals, which tests were sent with patients, and which were repeated on trauma center arrival. Overall, results from 246 of 283 (86.9%) laboratory tests and 241 of 249 (96.8%) radiographs done at referring hospitals were sent with patients. Repetition of laboratory tests at the receiving hospital was frequent regardless of whether initial results were sent (P = .6 by chi2), and radiograph repetition was unrelated to whether sent films were originals or copies (P = .2 by chi2). For these 104 patients, the receiving hospital charged $66,463 for repetition of work-up done at referring facilities.

Adult↗
PubMed2000

Effectiveness of delayed activated charcoal administration in simulated paracetamol (acetaminophen) overdose.

AIMS: Oral activated charcoal is used to treat drug overdose and is effective at reducing drug absorption when administered within 1 h of drug ingestion. There are fewer data on efficacy when the delay is longer, as is the case in most drug overdoses. This study investigated the efficacy of activated charcoal at preventing paracetamol (acetaminophen) absorption after simulated overdose when administration was delayed between 1 and 4 h. METHODS: An open randomized-order four-way crossover study was performed in healthy volunteers comparing the effect of activated charcoal 50 g on the absorption of 3 g paracetamol tablets when administered after an interval of 1, 2 or 4 h or not at all. Plasma paracetamol concentrations were measured over 9 h after paracetamol ingestion using h.p.l.c. and areas under the curve between 4 and 9 h (AUC(4,9 h)) calculated as a measure of paracetamol absorption. RESULTS: Activated charcoal significantly reduced paracetamol AUC(4,9 h) when administered after 1 h (mean reduction 56%; 95% Confidence intervals 34, 78; P<0.002) or 2 h (22%; 6, 39; P<0.03) but not after 4 h (8%; -8, 24). When administered after 1 h activated charcoal reduced individual plasma paracetamol concentrations significantly at all times between 4 and 9 h after paracetamol administration. Administration at 2 or 4 h had no significant effect. CONCLUSIONS: These results in healthy volunteers cannot be extrapolated directly to poisoned patients. However, they provide no evidence of efficacy for activated charcoal when administered after an interval of more than 2 h.

Acetaminophen↗
PubMed2000

Etomidate versus succinylcholine for intubation in an air medical setting.

The objective was to compare rates of successful endotracheal intubation (ETI) and requirement for multiple ETI attempts in patients receiving etomidate (ETOM) versus succinylcholine (SUX). This retrospective study analyzed adults in whom oral ETI was attempted by a helicopter EMS (HEMS) service between July 1997 to July 1999. Data were from records of the HEMS service, which uses a RN/EMTP crew; analysis was with chi-square and logistic regression (P = .05). ETI was successful in 269 (97.8%) of 275 patients, with multiple attempts occurring in 54 (20.1%) of 269. Success rates for SUX (209 of 213, 98.1%) and ETOM (60 of 62, 96.8%) were similar (P = .62). However, of 60 ETOM patients successfully intubated, 7 (11.7%) required rescue succinylcholine. When these patients are tallied as ETOM failures and SUX successes, resultant success rates for ETOM (86.9%) and SUX (98.2%) are different (P = .001). ETOM patients were more likely (P = .004) than SUX patients to require multiple attempts (33.3% versus 16.3%). ETI success rates were high in patients receiving SUX or ETOM as primary adjuncts for airway control, but initial success was more likely with SUX, and ETOM patients were more likely to require multiple attempts.

Adolescent↗
PubMed2000

Appropriateness of endotracheal tube size and insertion depth in children undergoing air medical transport.

OBJECTIVES: Guidelines for pediatric endotracheal tube (ETT) size and insertion depth are important in the helicopter EMS (HEMS) setting, where intubated patients are frequently transported by a non-physician flight crew providing protocol-based care in an environment noted for limitations in clinical airway assessment. The objectives of this study were to characterize, in a HEMS pediatric population, the frequency of compliance with guideline-recommended ETT size and insertion depth, and to test for association between guideline noncompliance and subsequent receiving hospital adjustment of ETT size or insertion depth. DESIGN: This retrospective review analyzed 216 consecutive pediatric (age <14) scene and interfacility HEMS transports, of patients intubated before or during HEMS transport, by an urban two-helicopter HEMS service providing protocol-based care with a nurse/paramedic crew configuration. Patients were transported to one of three receiving academic pediatric referral centers. Pediatric Advanced Life Support (PALS) criteria for ETT size and insertion depth were used to assess guideline-appropriateness of pediatric ETTs. Receiving hospital records were reviewed to determine if post-transport ETT size or lipline adjustment were associated with guideline-appropriateness of size and lipline during HEMS transport. Univariate (chi-square and Fisher's exact) and multivariate (logistic regression) statistics were used to assess and control for the following covariates: intubator group (physician, flight crew, ground EMS), transport year, sex, age, transport type (scene versus interfacility), and receiving hospital. For all analyses, statistical significance was set at the 0.05 level. RESULTS: The initial ETT size was within 0.5 mm of guideline-recommended sizes in 178 (83.6%) of the 213 patients for whom this data were available. Inappropriate sized ETTs were nearly always (32 of 35, 91.4%) too small. Compared to initial ETTs placed by ground EMS personnel, initial ETTs placed by flight crew or physicians were more likely to be appropriate as defined by guidelines (P = .008 and .032, respectively). Receiving hospitals changed the ETT size in 18 (8.3% of 216) cases. Receiving hospital ETT size change was more likely with later transport year (P = .018) and less likely in patients over 2 years of age (P = .03); there was no significant association between receiving hospital ETT size change and intubator group (P > .22) or guideline-appropriateness of ETT size (P = 0.94). The initial ETT insertion depth was within 1 cm of the guideline-recommended lipline in 86 (43.2%) of the 199 patients for whom this data were available. Inappropriate liplines were almost always (109 of 113, 96.5%) too deep. Compared to initial ETT liplines determined by ground EMS personnel, initial liplines determined by flight crew (P = .007), but not physician (P = .47) were more likely to be appropriate as defined by guidelines. Receiving hospitals changed the ETT insertion depth in 72 (33.3% of 216) cases. Receiving hospital lipline change was more likely (P = .03) in patients older than 2 years of age, but was not associated with intubator group (P = .75) or lipline guideline-appropriateness (P = .35). CONCLUSIONS: As judged by frequently used guidelines, pediatric ETTs are often too small and commonly inserted too deep. However, this retrospective study, limited by lack of clinical correlation for ETT size and insertion depth, failed to find an association between lack of ETT size or lipline guideline compliance and subsequent ETT adjustment at receiving pediatric centers. This study's findings, which should be confirmed with prospective investigation, cast doubt upon the utility of pediatric ETT size/lipline guidelines as strict clinical or quality assurance tools for use in pediatric airway management.

Age Factors↗
PubMed1999

Congenital anomalies after prenatal ecstasy exposure.

Prospective follow-up of 136 babies exposed to ecstasy in utero indicated that the drug may be associated with a significantly increased risk of congenital defects (15.4% [95% CI 8.2-25.4]). Cardiovascular anomalies (26 per 1000 livebirths [3.0-90.0]) and musculoskeletal anomalies (38 per 1000 [8.0-109.0]) were predominant.

Abnormalities, Drug-Induced↗
PubMed1999

Patient and physician agreement on abdominal pain severity and need for opioid analgesia.

Whereas controversy surrounds emergency department (ED) analgesia administration to patients with undifferentiated abdominal pain, few studies have addressed the level of patient-physician agreement on abdominal pain severity and need for opioid analgesia. This prospective study was undertaken to assess concordance between emergency physicians and patients on abdominal pain severity. Study subjects were a convenience sample of 30 adults seen in an urban university-affiliated tertiary care ED (annual census 65,000) who had undifferentiated abdominal pain meeting an initial severity threshold of 5 on a 10 cm visual analog scale (VAS) marked by the patient. Patients' and physicians' VAS scores, obtained in blinded fashion at presentation (t0) and at one (t1) and two (t2) hours into the ED stay, were compared with t test (VAS scores) and sign-rank (percent change in VAS scores) analyses. In addition, patients and physicians were asked at each assessment time, in blinded fashion, "Is the pain severe enough to warrant morphine?" The kappa statistic was used to characterize the degree of agreement between physician and patient assessments as to whether opioids were indicated. At t0, t1, and t2, patients' mean VAS scores (7.5, 6.7, and 5.1) were significantly (P < .05) higher than the corresponding physicians' VAS scores (5.3, 4.7, and 3.9). Though VAS scores for physicians started lower than those of patients, the percentage changes in scores from one assessment to the next were similar by Wilcoxon sign-rank testing (P > .50 for time intervals t0 - t1 and t1 - t2). Overall, patients and physicians agreed on the question of whether pain was sufficient to warrant opioids in 71 of 90 (78.9%) assessments; the corresponding kappa statistic of .57 indicated moderate agreement (P < .0001). These results, indicating that patients and physicians usually agree on whether opioids are warranted for abdominal pain, have important implications for further research on ED analgesia in this population.

Abdominal Pain↗
PubMed1999

The use of atypical antipsychotics in the management of schizophrenia.

Long-term drug treatment of schizophrenia with conventional antipsychotics has limitations: an estimated quarter to one third of patients are treatment-resistant; conventional antipsychotics have only a modest impact upon negative symptoms (poverty of thought, social withdrawal and loss of affect); and adverse effects, particularly extrapyramidal symptoms (EPS). Newer, so-called atypical, antipsychotics such as olanzapine, risperidone, sertindole and clozapine (an old drug which was re-introduced in 1990) are claimed to address these limitations. Atypical agents are, at a minimum, at least as effective as conventional drugs such as haloperidol. They also cause substantially fewer extrapyramidal symptoms. However, some other adverse effects are more common than with conventional drugs. For example, clozapine carries a significant risk of serious blood disorders, for which special monitoring is mandatory; it also causes troublesome drowsiness and increased salivation more often than conventional agents. Some atypical agents cause more weight gain or QT prolongation than older agents. The choice of therapy is, therefore, not straightforward. At present, atypical agents represent an advance for patients with severe or intolerable EPS. Most published evidence exists to support the use of clozapine, which has also been shown to be effective in schizophrenia refractory to conventional agents. However, the need for compliance with blood count monitoring and its sedative properties make careful patient selection important. The extent of any additional direct benefit offered by atypical agents on negative symptoms is not yet clear. The lack of a depot formulation for atypical drugs may pose a significant practical problem. To date, only two double-blind studies in which atypical agents were compared directly have been published. Neither provides compelling evidence for the choice of one agent over another. Atypical agents are many times more expensive than conventional drugs. Although drug treatment constitutes only a small proportion of the costs of managing schizophrenia, the additional annual cost of the use of atypical agents in, say, a quarter of the likely U.K. schizophrenic population would be about 56 M pound sterling. There is only limited evidence of cost-effectiveness. Atypical antipsychotics are not currently licensed for other conditions where conventional antipsychotics are commonly used, such as behaviour disturbance or dementia in the elderly. Their dose, and place in treatment in such cases have yet to be determined.

Antipsychotic Agents↗
PubMed1998

Elder patients with closed head trauma: a comparison with nonelder patients.

OBJECTIVE: Little is known about the circumstances surrounding closed head trauma (CHT) in elders, and how they differ from nonelders. The study objective was to compare the 2 populations for outcome (positive cranial CT scan depicting traumatic injury, or the need for neurosurgery), mechanism of injury, and the value of the neurologic examination to predict a CT scan positive for traumatic injury or the need for neurosurgical intervention. METHODS: A retrospective study was conducted by collecting a case series of patients with blunt head trauma who underwent CT scanning, and comparing elder (aged > or =60 years) with nonelder patients. The setting was the ED of a university-affiliated Level-1 trauma center. RESULTS: Twenty percent of the elders and 13% of the nonelders had CT scans positive for traumatic injury, which conferred a risk ratio of 1.58 (95% CI 1.21-2.05). Older women were more at risk for the need for neurosurgery than were younger ones (3.1 vs 0.3%, RR 10.66, 95% CI 1.26-90.46). Among the elders, falls were the dominant mechanism of closed head trauma, followed by motor vehicle collisions (MVCs), then being struck as a pedestrian. In the nonelders, MVCs, falls, and assaults were the most important mechanisms of injury. A focally abnormal neurologic examination imparted an increased risk for both a CT scan positive for traumatic injury (elder 4.39, 95% CI 2.91-6.62; nonelder 7.75, 95% CI 5.53-10.72) and the need for neurosurgery (elder 35.68, 95% CI 4.58-275.89; nonelder 142.58, 95% CI 19.11-1064.22) in both age groups. CONCLUSIONS: Significant differences exist between elder and nonelder victims of CHT with respect to mechanisms of trauma and outcomes (CT scan positive for traumatic injury, or the need for neurosurgery).

Adolescent↗