L. Jane Goldsmith

Effects of sevoflurane anaesthesia on recovery in children: a comparison with halothane

We prospectively studied one hundred ASA physical status I–II children, ages six months to six years, undergoing myringotomy surgery. Children were randomly assigned to one of four anaesthetic groups receiving either halothane or sevoflurane for anaesthesia and oral midazolam premedication or no premedication. We found that children anaesthetized with sevoflurane had significantly faster recovery times and discharge home times than those who received halothane. Patients given oral midazolam premedication had significantly longer recovery times, but no delay in discharge home compared with those not premedicated. However, children anaesthetized with sevoflurane and no premedication had an unacceptably high incidence (67%) of postoperative agitation. The use of oral midazolam preoperatively did decrease the amount of postoperative agitation seen with sevoflurane. We conclude that although sevoflurane does shorten recovery times, the degree of associated postoperative agitation makes it unacceptable as a sole anaesthetic for myringotomy surgery.

Postpartum contraceptive use among adolescent mothers

Objective To compare the incidence of repeat pregnancy and method continuation rate at 12 months postpartum in young women who chose either depot medroxyprogesterone acetate or oral contraceptives (OCs) as contraception. Methods We conducted a prospective cohort study of 122 postpartum women younger than 18 years of age who delivered between January 8, 1997 and December 31, 1997. Patients choosing depot medroxyprogesterone acetate (n = 76) and OCs (n = 46) were accrued for 12 months and were followed-up for a minimum of 12 months. Main outcome measures were median contraceptive method continuation and the incidence of repeat pregnancy at 12 months postpartum. Results There was no difference in mean age at delivery (P = .47), parity (P = .84), or gravidity (P = .78) between depot medroxyprogesterone acetate and OC users. At 12 months postpartum, 27.4% of OC users and 55.3% of depot medroxyprogesterone acetate users were still using contraception. Median time to contraceptive discontinuation was longer for those choosing depot medroxyprogesterone acetate compared with OCs (17.8 vs 7.4 months, respectively, P = .002). The overall incidence of repeat pregnancy at 12 months postpartum was 10.6%. Among OC and depot medroxyprogesterone acetate users, respectively, 24% and 2.6% became pregnant again, producing a relative risk (RR) of 9.09 (95% confidence interval [CI] 2.1, 39.2) for repeat pregnancy among OC users. The mean time to repeat pregnancy (this was reported instead of the median time whenever the pregnancy rate had not reached 50% at the end of the follow-up period) was longer for depot medroxyprogesterone acetate compared with OC users (17.1 months vs 13.2 months, respectively, P < .001). Conclusion Adolescent mothers using depot medroxyprogesterone acetate injection for contraception have a higher method continuation rate and a lower incidence of repeat pregnancy at 12 months postpartum than those selecting OCs during the same period.

Comparison of a two-finger versus two-thumb method for chest compressions by healthcare providers in an infant mechanical model☆

OBJECTIVE To compare the two-finger versus the two-thumb method of chest compression on an infant model. METHOD STUDY an unblinded, prospective, cross-over experimental study. SETTING the metropolitan area of a city with a population of greater than 260,000. PARTICIPANTS pediatric medical personnel and emergency workers. Anyone unable to complete the study was excluded. INTERVENTIONS participants performed chest compressions on an infant mannikin for 2 min. PARTICIPANTS were randomized to use the two-finger method or the two-thumb method for the first minute. The investigators recorded the skillguide readings of green (correct), green and orange (too deep), red (wrong placement), or no light (too shallow). Sixty or more correct compressions were judged to be adequate. RESULTS Two hundred and nine participants completed the study. PARTICIPANTS included: 66 nurses, 45 EMTs, 38 physicians, 27 paramedics, 14 nurses assistants/emergency department technicians, 10 firefighters, five respiratory therapists, and four students. Seventy-one percent (149/209) of participants failed to give adequate compressions by either method. Only 40 participants performed adequate compressions using the two-thumb method (95% confidence interval. 14-25%). Thirty-eight participants gave adequate compressions using the two-finger method (95% confidence interval, 13-24%). No statistically significant difference existed between the two groups (P = 0.877; the McNemar test). A statistically significant difference was found in the number of shallow compressions for each method. Forty participants (19.1%) had more than 40 compressions that were too shallow versus 15 (7.2%) using the two-thumb method (P < 0.005). CONCLUSIONS Medical personnel often fail to give adequate compressions. The two-thumb method was as adequate as the two-finger method. Overall, more compressions were measured as shallow with the two-finger method.

The effect of smoking on energy expenditure and plasma catecholamine and nicotine levels during light physical activity

A number of studies have found that cigarette smoking causes an acute increase in resting energy expenditure, but the effect on energy expenditure during light physical activity is less clear. Since both smoking and activity have been shown to increase plasma catecholamines, these could produce additive effects on energy expenditure when smoking during light physical activity. In this study, the impact of cigarette smoking on energy expenditure, cardiovascular function, plasma nicotine and plasma catecholamine levels was determined in adult male subjects at rest and while engaged in light physical activity. Smoking at rest resulted in a 3.6% increase in energy expenditure above the resting baseline; whereas the increase in energy expenditure caused by smoking during light physical activity (compared with the light physical activity baseline) was 6.3%. This increase during light physical activity was significantly greater than the increase observed at rest (p < 0.025). As expected, plasma nicotine increased with smoking during both rest and light physical activity. An increase in plasma nicotine was associated with smoking during light physical activity. When this increase was adjusted as a covariate, the difference in smoking-related energy expenditure between light physical activity and rest disappeared, suggesting nicotine accounts for the effect. Plasma epinephrine and norepinephrine levels increased with smoking and showed a significantly greater increase during light physical activity compared to rest. Cigarette smoking caused a significantly greater increase in heart rate during light physical activity than it did while at rest, but there was no significant effect of smoking on mean blood pressure. It was concluded that there is enhanced energy expenditure associated with cigarette smoking during light physical activity when compared with smoking at rest which could be due in part to smoking-induced increases in circulating plasma catecholamines and perhaps nicotine.

Observer differentiation of proximal enamel mechanical defects versus natural proximal dental caries with computed dental radiography

OBJECTIVES Various models have been used to study the accuracy of imaging systems for detection of dental caries. This study compares the ability of dentists to detect mechanically created defects versus natural dental caries cavitations on the proximal surfaces of extracted teeth with Computed Dental Radiography (Schick Industries, Long Island City, N.Y.). Detection rates are investigated according to lesion depth to permit comparisons to be made between studies in the literature with other mechanical defects or natural caries models. Discrimination of natural caries versus artificial defects with Computed Dental Radiography is also compared with a previous report that used standard dental film. STUDY DESIGN Fifty-two extracted molar and premolar teeth were mounted into representative sets of maxillary and mandibular posterior arches for bite-wing radiography. There were 16 proximal surfaces with natural caries and 28 proximal surfaces with mechanical defects. An optical bench was used to ensure constant beam geometry. A 1.8 cm acrylic soft tissue equivalent attenuator was placed in front of the receptor. Thirty dentists acted independently as observers to differentiate between sound proximal tooth surfaces, natural dental caries, and mechanical defects. Evaluation of intra- and interobserver variability was made with use of the kappa statistic. The Zelen test of odds ratios was used to test for homogeneity, and the Mantel-Haenszel analysis plus stratified logistic regression were used for inference about the common odds ratio. Significance was set at p < 0.05. RESULTS AND CONCLUSIONS Ignoring stipulation of cavity type, detection was 74% for mechanical defects and 67% for natural caries. The odds of detecting a mechanical defect were 1.40 times the odds of finding natural dental caries cavitation of the same depth. Lesion depth did influence the probability of correctly identifying the presence of a lesion; the odds of identifying cavitation increased 1.41 times with every 0.1 mm increase in lesion depth. Correct designation of lesion type was 1.42 times more likely with mechanical defects than with natural caries (p = 0.003). Intraobserver (kappa = 0.65) and interobserver (kappa = 0.43) agreements were fair to good. Discrimination between natural and artificial lesions was less with the Computed Dental Radiography than that found in our previous study with standard direct emulsion x-ray film.

A Statistical Analysis of the Accuracy of Sonography of the Patellar Tendon

The purpose of this study was to evaluate the accuracy of sonography in measuring the dimensions of the cadaveric patellar tendon to determine whether sonography might have future applications in the preoperative assessment of autograft tissues before anterior cruciate ligament (ACL) reconstruction. Eleven lower-extremity human cadaveric limbs, with an average donor age of 75 years (range, 67 to 87 years), underwent patellar sonography with a 7.5-MHz transducer. Patellar tendon thickness, width, and length were measured sonographically. After skin removal, the patellar tendon dimensions were measured manually. Sonographic and manual measurements were compared statistically. Sonographic and manual measurements showed good agreement for thickness. There was poor agreement for width and length. Because of its limited accuracy, sonography cannot be recommended for the measurement of the patellar tendon before ACL reconstruction.

Observer differentiation of mechanical defects versus natural dental caries cavitations on monitor-displayed images with imaging plate readout.

OBJECTIVE The purpose of this study was to compare the ability of dentists to detect mechanically created defects vs natural dental caries cavitations on the proximal surfaces of extracted teeth by means of storage phosphor imaging plate technology. STUDY DESIGN Fifty-two extracted molar and premolar teeth were blocked into sets for bitewing radiographs through use of the DIGORA digital imaging system. Sixteen natural caries cavities and 28 artificial lesions were present in the 80 proximal surfaces included in the study. A group of 16 dentists assessed proximal lesions on unenhanced images on the monitor and 1 month later on contrast-enhanced images. A different group of 16 dentists assessed proximal lesions on contrast-enhanced images and 1 month later on unenhanced images. The Mann-Whitney U test was used to check for a reading-order effect. The Zelen test of odds ratio was used to test for homogeneity, and the Mantel-Haenszel analysis or stratified logistic regression was used for inference about the common odds ratio. Alpha was set at P < .05. RESULTS AND CONCLUSIONS With the DIGORA system, there was little difference between the detection rates of mechanical defects and natural carious cavities with unenhanced images, but the mechanical defects were more readily detected when contrast-enhanced images were used. Cavity depth positively affected the odds of diagnosis of lesions, with deeper lesions being more readily detected than more superficial ones irrespective of whether they were natural or artificial. In comparison with findings of previous studies in which film and a charge-coupled device detector were used, the overall detection rate for natural dental caries was remarkably constant across the modalities.

Transdermal nicotine patches do not cause clinically significant gastroesophageal reflux or esophageal motor disorders.

Transdermal nicotine delivery systems are widely used in smoking cessation. The purpose of this study was to determine whether common symptoms of pyrosis and dyspepsia associated with these patches are related to gastroesophageal reflux or esophageal dysmotility. Twenty-seven paid volunteer cigarette smokers (> 15 cigarettes/day) without symptomatic gastroesophageal reflux disease participated in this single-blinded, placebo-controlled study. Twenty subjects completed the study. Subjects underwent three sequential 24-h intraesophageal pH/motor studies (Synectics model T32342084, Shore View, MN). The pH/motility probe was positioned 5 cm above the manometrically determined LES. A placebo patch was applied for the first 24-h study and a 15-mg nicotine patch (Nicotrol) was applied for the initial 16 h (removed for remaining 8 h) of the second 24-h period. A 21-mg nicotine patch (Nicoderm) was applied for another 24-h study period. All subjects consumed an identical, defined diet documented by meal receipts, and refrained from smoking and tobacco use throughout the study periods (CO breath test confirmation). The Wilcoxon, paired t-test, exact McNemar statistical methods were used. The results showed that there were no significant differences in reflux symptoms (pyrosis, chest pain, nausea, dysphagia), supine gastroesophageal reflux (number of episodes, duration, or cumulative acid exposure), or the total number of reflux episodes between placebo and nicotine patch treatment periods. The number of post-prandial upright acid reflux episodes (p = 004) and number of upright acid reflux episodes lasting more than 5 min (p = 0.007) were statistically higher with the placebo patch compared to the active nicotine patches. No differences in intraesophageal pH or motility indices were noted between the two transdermal nicotine patches (Nicotrol, Nicoderm). It was concluded that dyspeptic symptoms in subjects utilizing transdermal nicotine patches are not related to gastroesophageal reflux or to esophageal motor abnormalities.

Nonspecific Human IgG Reduces Survival in Neonatal Rats Infected with Escherichia coli

Background: Human intravenous IgG (IVIG) containing specific antibodies protects neonatal rats from septic death. However, IVIG has immunosuppressive properties and clinical trials of IVIG in neonates at risk for sepsis have yielded conflicting results. Hypothesis: This study was designed to test the hypothesis that nonspecific antibodies in IVIG reduce survival in neonatal rats infected with Escherichia coli. Methods: Specific antibodies were adsorbed from IVIG with E coli to produce IVIG/anti‐E coli −. After transthoracic administration of E coli, survival was determined in neonatal rats injected intraperitoneally with phosphate‐buffered saline, IVIG/anti‐E coli − (500 mg/kg) or IVIG containing anti‐E coli antibodies (IVIG/anti‐E coli +). Complement‐mediated hemolytic activity of neonatal rat serum was quantified using sensitized sheep erythrocytes. Results: Compared with placebo, intraperitoneal IVIG/anti‐E coli − reduced neonatal survival after E coli infection. In contrast, IVIG/anti‐E coli + protected infected animals. Both IVIG/anti‐E coli − and IVIG/anti‐E coli + impaired the complement‐mediated hemolytic activity of neonatal rat serum. Conclusions: IVIG contained (1) nonspecific antibodies that reduced survival in neonatal rats infected with E coli and (2) protective anti‐E coli antibodies that enhanced survival in neonatal rats infected with E coli. We speculate that in clinical trials of IVIG to treat or prevent neonatal sepsis, inconsistent results may be caused, in part, by lot‐to‐lot variations in the ratio of immunosuppressive, nonspecific antibodies to protective, specific antibodies.