Biomedical subjects

Karl Sylvester

Publications and source records attributed to Karl Sylvester.

5 recordsLinked to original sources

PubMed2007

Matched analysis of nonoperative management vs immediate appendectomy for perforated appendicitis.

BACKGROUND: The role of nonoperative therapy vs immediate appendectomy in the management of children with perforated appendicitis remains undefined. The objective of this study was to rigorously compare these management options in groups of patients with matched clinical characteristics. METHODS: Multicenter case-control study was conducted from 1998 to 2003. We compared patients treated nonoperatively vs those undergoing appendectomy to identify differences in 12 clinical parameters. We then generated a second control group of patients matched for these variables and compared the following outcomes in these clinically similar groups: complication rate, abscess rate, and length of stay (LOS). Analysis was performed according to intention-to-treat principles, using chi2, Fisher exact, and Student t tests. RESULTS: The only significant difference between patients treated nonoperatively and those treated by appendectomy was the duration of pain on presentation (6.8 vs 3.1 days of pain). We created a second control group of patients undergoing immediate appendectomy matched on duration of pain on presentation to patients treated nonoperatively. These groups continued to be clinically comparable for the other 11 parameters. Compared to this matched control group, the nonoperative group had fewer complications (19% vs 43%, P < .01), fewer abscesses (4% vs 24%, P < .01), and a trend for shorter LOS (6.5 +/- 5.7 vs 8.8 +/- 6.7 days, P = .08). CONCLUSIONS: When nonoperative management for perforated appendicitis was studied using appropriately matched clinical controls, we found that it resulted in a lower complication rate and shorter LOS in the subset of patients presenting with a long duration of pain. Our data suggest that nonoperative management should be prospectively evaluated in children with perforated appendicitis presenting with a history of pain exceeding 5 days.

Adolescent↗

PubMed2006

Sleeping position, oxygen saturation and lung volume in convalescent, prematurely born infants.

OBJECTIVE: To determine whether the effects of sleeping position on lung volume and oxygenation are influenced by postmenstrual age (PMA) and oxygen dependency in convalescent prematurely born infants. DESIGN: Prospective study. SETTING: Tertiary neonatal unit. PATIENTS: 41 infants (21 oxygen dependent), median gestational age 28 weeks (range 24-31 weeks) and birth weight 1120 g (range 556-1780 g). INTERVENTION: Infants were studied both supine and prone at two-weekly intervals from 32 weeks' PMA until discharge. Each posture was maintained for 1 h. MAIN OUTCOME MEASURES: Pulse oximeter oxygen saturation (Spo(2)) was monitored continuously, and at the end of each hourly period functional residual capacity (FRC) was measured. RESULTS: Overall, lung volumes were higher in the prone position throughout the study period; there was no significant effect of PMA on lung volumes. Overall, Spo(2) was higher in the prone position (p = 0.02), and the effect was significant in the oxygen-dependent infants (p = 0.03) (mean difference in Spo(2) between prone and supine was 1.02%, 95% CI 0.11% to 1.92%), but not in the non-oxygen-dependent infants. There was no significant influence of PMA on Spo(2). CONCLUSION: In the present study, prone sleeping did not improve oxygenation in prematurely born infants, 32 weeks' PMA or older and with no ongoing respiratory problems. However, the infants were monitored in each position for an hour, thus it is recommended that oxygen saturation should continue to be monitored after 32 weeks' PMA to be certain that longer periods of supine sleeping are not associated with loss of lung volume and hypoxaemia.

Functional Residual Capacity↗

PubMed2005

Twitch airway pressure elicited by magnetic phrenic nerve stimulation in anesthetized healthy children.

Children with diaphragm dysfunction may be unable to maintain adequate ventilation. Accurate diagnosis is important, but can only be achieved using an appropriate test and reference range. The aim of this study, therefore, was to measure diaphragm contractility and examine the influence of age and maturation, using magnetic phrenic nerve stimulation in healthy children. Anterolateral magnetic stimulation (MS) of the phrenic nerves was performed using a 43-mm figure-eight coil in 23 children (14 male; mean age, 7.8 years; range, 1.8-15.7) anesthetized for minor surgery with sevoflurane gas. The airway was maintained with a cuffed laryngeal mask airway (LMA) which was briefly occluded during MS. Diaphragm contractility was assessed by measuring the airway pressure (TwPaw) elicited by MS. TwPaw responses were obtained in all subjects, with mean (SD) TwPaw 18.2 (6.8) cm H2O bilateral, 7.3 (3.2) cm H2O left unilateral, and 8.6 (3.1) cm H2O right unilateral. Subgroup analysis was performed in 17 of the children who were prepubertal. Their mean (SD) TwPaw was 17.3 (6.8) cm H2O bilateral, 7.1 (3.7) cm H2O left unilateral, and 8.3 (3.3) right unilateral. The mean (SD) intrapatient coefficients of variation for bilateral and left and right unilateral TwPaw were 8.4% (5.2), 6.7% (3.5), and 11.7% (10.3), respectively. Bilateral and left and right unilateral TwPaw were significantly related to age (P < 0.05). In healthy prepubertal children, diaphragm contractility is primarily influenced by age.

Adolescent↗

PubMed2002

New directions in bioabsorbable technology.

Generating replacement tissues requires an interdisciplinary approach that combines developmental, cell, and molecular biology with biochemistry, immunology, engineering, medicine, and the material sciences. Because basic cues for tissue engineering may be derived from endogenous models, investigators are learning how to imitate nature. Endogenous models may provide the biological blueprints for tissue restoration, but there is still much to learn. Interdisciplinary barriers must be overcome to create composite, vascularized, patient-specific tissue constructs for replacement and repair. Although multistep, multicomponent tissue fabrication requires an amalgamation of ideas, the following review is limited to the new directions in bioabsorbable technology. The review highlights novel bioabsorbable design and therapeutic (gene, protein, and cell-based) strategies currently being developed to solve common spine-related problems.

Absorbable Implants↗

PubMed2002

New directions in bioabsorbable technology.

Generating replacement tissues requires an interdisciplinary approach that combines developmental, cell, and molecular biology with biochemistry, immunology, engineering, medicine, and the material sciences. Since the basic cues for tissue engineering may be derived from endogenous models, investigators are learning how to imitate nature. Endogenous models may provide the biologic blueprints for tissue restoration, but there is still much to learn. Interdisciplinary barriers must be overcome to create composite, vascularized, patient-specific tissue constructs for replacement and repair. Although multistep, multicomponent tissue fabrication requires an amalgamation of ideas, the following review is limited to the new directions in bioabsorbable technology. The review highlights novel bioabsorbable design and therapeutic (gene, protein, and cell-based) strategies that are currently being developed to solve common spinal problems.

Absorbable Implants↗