Extending the preoxygenation period from 4 to 8 mins in critically ill patients undergoing emergency intubation.

OBJECTIVE: To determine the effectiveness of increasing the preoxygenation period with 100% oxygen in the critically ill patient from 4 to 8 mins in preparation for emergency tracheal intubation. DESIGN: Nonrandomized, controlled trial. SETTING: Large, level one trauma center, tertiary care intensive care unit. PATIENTS: Critically ill patients failing noninvasive respiratory support techniques who required tracheal intubation followed by mechanical ventilation. INTERVENTIONS: A baseline arterial blood gas was obtained on noninvasive passive therapy and at 4, 6, and 8 mins of active preoxygenation efforts with 100% oxygen therapy with a noncollapsing resuscitator bag and mask. Best effort to achieve a tight fitting mask seal was pursued coupled with other mask ventilation maneuvers to optimize noninvasive oxygenation and ventilation. MEASUREMENTS AND MAIN RESULTS: Thirty-four patients consecutively intubated by the author during the 7-month study period were studied. The baseline PaO2 (mean +/- SD) with concurrent noninvasive support was 61.9 +/- 14.6 mm Hg (range: 44-109 mm Hg) and increased a mean of 22 mm Hg to 83.8 +/- 51.5 mm Hg after 4 mins of preoxygenation (p < 0.01). Continued preoxygenation efforts (6 mins) increased the PaO2 to 88.2 mm Hg +/- 48.5 and after 8 mins to 92.7 mm Hg +/- 55.2. At the 8-min mark, 5 of 34 patients achieved > 10% increase in their PaO2 and only two patients increased their 4-min PaO2 by > or = 50 mm Hg after the additional 4 mins of preoxygenation. One quarter of the patients experienced a reduction in their PaO2 from the 4 to the 8-min time period. Nearly, 50% of the patients met the criteria for desaturation during the intubation procedure. CONCLUSIONS: Extending the preoxygenation period from the customary 4 mins to either 6 or 8 min seems to be marginally effective in the majority of patient suffering from cardiopulmonary deterioration and such an extension may jeopardize oxygenation efforts in some patients.

Endodontic treatment outcome: effect of the permanent restoration.

OBJECTIVE: To investigate the relationship between the presence of the coronal restoration and endodontic treatment success or failure. METHODS: This study comprised 200 endodontically treated teeth with 441 roots. Follow-up examination was conducted 4 +/- 0.5 years after completion of endodontic treatment. Outcome criteria were modified from Strindberg. RESULTS: Teeth/roots restored with permanent coronal restoration (casting or filling) had a higher success rate (80%) than teeth/roots not restored (60%; P < .01) in the analysis of aggregate data. However, the results of stratified analysis on key confounding factor (preoperative periapical diagnosis) showed that there is no significant association between the presence of permanent restoration and endodontic outcome. Teeth with preoperative apical periodontitis were less likely to be restored with a crown (23.9%) than teeth without apical periodontitis (76.1%; P < .01). Anterior teeth were more likely to be restored with a filling and sooner than the posterior teeth. These associations suggest a treatment selection bias. CONCLUSIONS: Stratified analysis on the key confounding factor reveals that endodontic outcome is driven by the presence of preoperative root canal infection (apical periodontitis). Lack of stratification on key confounding factors inaccurately suggests that presence of permanent restoration contributes to the success of endodontic treatment in the aggregate analysis of grouped data. The choice to restore the tooth as well as the choice and timing of permanent restoration may be the result of a bias in treatment selection. Stratified analysis on key confounding factors is the key to valid analysis and accurate results.

Effects of topical L-selenomethionine with topical and oral vitamin E on pigmentation and skin cancer induced by ultraviolet irradiation in Skh:2 hairless mice.

BACKGROUND: The antioxidants selenium and vitamin E can be effective in reducing acute and chronic ultraviolet (UV)-induced skin damage. OBJECTIVE: This study investigated whether topical L-selenomethionine with topical RRR-alpha-tocopherol (Eol) or oral RRR-alpha-tocopheryl acetate (Eac) can reduce the incidence of UV-induced skin damage more than treatment with each alone. METHODS: Skh:2 hairless pigmented mice were treated with lotion vehicle, L-selenomethionine lotion, Eol lotion, oral Eac, L-selenomethionine plus Eol lotion, or L-selenomethionine lotion plus oral Eac and exposed to UVB. Skin pigmentation was scored, and the number of skin tumors per animal was counted weekly. RESULTS: Mice treated with selenium and vitamin E had significantly less acute and chronic UV-induced skin damage. CONCLUSION: Topical L-selenomethionine alone and combined with vitamin E gave the best protection against UV-induced blistering and pigmentation. In protecting against skin cancer, topical Eol and topical L-selenomethionine plus oral Eac were best. Significant synergy of L-selenomethionine with vitamin E was not observed.

Endodontic infection: some biologic and treatment factors associated with outcome.

OBJECTIVE: We sought to investigate the simultaneous effect of apical periodontitis, instrumentation level, and density of root canal filling on endodontic treatment outcome. METHODS: For this study, 200 endodontically treated teeth with 441 roots were used. A follow-up examination was conducted 4 +/- 0.5 years postoperatively. Data were subjected to univariate and multivariate analysis. RESULTS: Periapical pathosis had the strongest effect on treatment outcome (P <.0001). The instrumentation level (mean +/- SEM of the working length) for successfully treated teeth/roots with normal preoperative pulp and periapex was farther away from the radiographic apex (1.23 +/- 0.13 mm) than for teeth/roots with an unsuccessful outcome (0.20 +/- 0.09 mm; P <.005). However, successfully treated teeth/roots with pulp necrosis and apical periodontitis had working length levels closer to the radiographic apex (0.55 +/- 0.12 mm) than did teeth/roots with unsuccessful outcomes (1.73 +/- 0.30 mm; P<.001). In teeth/roots with apical periodontitis, a millimeter loss in working length increased the chance of treatment failure by 14%. The risk of failure was higher for a fair/poor density of obturation than for a good density for all diagnoses of periradicular status. CONCLUSION: Diseased periapex, level of working length relative to the radiographic apex, and fair/poor density all affect the outcome of endodontic treatment.

Inguinal hernia in preterm infants (< or = 32-week gestation).

The current incidence of inguinal hernia (IH) in premature infants is not well-established. It is also unclear whether common co-morbidities in this population, i.e., chronic lung disease (CLD) or nutritional status or both contribute to the development of IH. The purpose of this study was to establish the epidemiologic profile of preterm infants of 32 weeks gestational age (GA) or less at birth with IH and determine whether the severity of CLD or poor nutritional status predisposes to the development of IH. Perioperative profiles of infants undergoing surgery were also reviewed. A retrospective study of 1,057 infants born at 23-32 weeks GA from January 1990 to December 1995 was done. Specific risk and demographic factors were identified. Factors used to determine severity of CLD were: days on intermittent mandatory ventilation (IMV); days on positive pressure (IMV + continuous positive airway pressure); and total number of days on supplemental oxygen. Overall nutritional status was determined by weight gain in g/kg per day. The incidence of IH in preterm infants of 32 weeks GA or less who were admitted for 28 days or more was 9.34% (65/696) prior to discharge. The incidence in infants weighing 1,500 g or less was 11.11% (63/567) and in infants 1,000 g or less 17.39% (48/276). All parameters that determined the severity of CLD were statistically significant in infants with IH by univariate analysis. In a multivariate regression model, male gender was the most important variable that was significantly associated with IH (odds ratio OR=9.6; 95% confidence interval CI=3.90-23.59), followed by total days on supplemental oxygen (adjusted OR=1.00; 95% CI= 1.01-1.02). Weight gain (g/kg per day) was not significantly different between the two groups. Surgical correction before discharge was well tolerated. We conclude that the incidence of IH is GA-dependent. Factors related to severity of CLD play a more important role than weight gain in predisposing to IH.

Biostatistical consultation for dental research.

Dental science researchers do not really need a detailed, ready-at-hand knowledge of statistics to design and perform high quality scientific research. Although the acquisition and utilization of such knowledge by dental researchers is not discouraged, it is proposed that it is more important for dental researchers to be committed to developing and maintaining a long term, ongoing, interactive consulting relationship with a biostatistician. The nature of this relationship will depend in large part on the complexity of the dental research being conducted. While the statistical consultant will assist in interpreting analytic results for the dental researcher, the latter will need to provide extensive input in assisting in the estimation of sample size and power, and for expressing scientific hypotheses in statistical terms so that the appropriate data analytic methodology can be specified.

Results of primary percutaneous transluminal coronary angioplasty plus abciximab with or without stenting for acute myocardial infarction complicated by cardiogenic shock.

This study examines the effects of abciximab as adjunctive therapy in primary percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction (AMI) complicated by cardiogenic shock. Abciximab improves the outcome of primary PTCA for AMI, but its efficacy in cardiogenic shock remains unknown. Case report forms were completed in-hospital and follow-up was obtained by telephone, outpatient visit, and review of hospital readmission records. A total of 113 patients with cardiogenic shock from AMI were included. All underwent emergency PTCA during which abciximab was administered to 54 patients (48%). The 2 groups of patients who received and did not receive abciximab were similar at baseline. Coronary stents were implanted slightly more often in the abciximab group (59% vs 42%; p = 0.1). A significantly improved final TIMI flow, less no-reflow, and a decrease in vessel residual diameter stenosis occurred in the abciximab group. At 30-day follow-up, the composite event rate of death, myocardial reinfarction, and target vessel revascularization was better in the abciximab group (31% vs 63%; p = 0.002). The combination of abciximab and stents was synergistic and resulted in improvement of all components of the composite end point beyond that seen with each therapy alone. Thus, abciximab therapy improves the 30-day outcome of primary PTCA in cardiogenic shock, especially when combined with coronary stenting.