Effect of fluctuation of oxygenation and time spent in the target range on retinopathy of prematurity in extremely low birth weight infants

BACKGROUND

The association between saturation of peripheral oxygenation (SpO2) fluctuation and severity of retinopathy of prematurity (ROP) is well elucidated in extremely low birth weight (ELBW) infants. Time spent in the Target range of SpO2 is also associated with the severity of ROP.

METHODS

In a prospective observational study, the SpO2 of all ELBW infants admitted to our unit were monitored for the first four weeks of life, and averaged every minute for analysis. The percent time spent at SpO2 <90%, 90-95%, and >95% and weekly SpO2 fluctuations [as SpO2 coefficient of variation (CoV)] were calculated.

RESULTS

During the study period 21 infants had moderate to severe ROP and 35 infants served as controls. Infants with moderate to severe ROP were smaller and younger than their controls [676±124 grams vs. 796±148 grams (p < 0.001); and 24.0±1.0 weeks vs. 25.0±1.7 weeks (p < 0.001) respectively]. There were no significant differences in time spent in the 90-95% range between groups (p = 0.66). However there was a significant increase in weekly SpO2 CoV in infants with moderate to severe ROP vs. controls (p = 0.007).

CONCLUSION

In ELBW infants, there was an association between SpO2 fluctuation during the first four weeks of life and severity of ROP, although, no association was established with time spent in the target range of SpO2.

A class of distribution-free models for longitudinal mediation analysis

Mediation analysis constitutes an important part of treatment study to identify the mechanisms by which an intervention achieves its effect. Structural equation model (SEM) is a popular framework for modeling such causal relationship. However, current methods impose various restrictions on the study designs and data distributions, limiting the utility of the information they provide in real study applications. In particular, in longitudinal studies missing data is commonly addressed under the assumption of missing at random (MAR), where current methods are unable to handle such missing data if parametric assumptions are violated.In this paper, we propose a new, robust approach to address the limitations of current SEM within the context of longitudinal mediation analysis by utilizing a class of functional response models (FRM). Being distribution-free, the FRM-based approach does not impose any parametric assumption on data distributions. In addition, by extending the inverse probability weighted (IPW) estimates to the current context, the FRM-based SEM provides valid inference for longitudinal mediation analysis under the two most popular missing data mechanisms; missing completely at random (MCAR) and missing at random (MAR). We illustrate the approach with both real and simulated data.

A laparoscopic approach reduces short-term complications and length of stay following ileocolic resection in Crohn's disease: an analysis of outcomes from the NSQIP database

AIM

Studies to date examining the impact of laparoscopy in resection for Crohn's disease on short-term morbidity have been limited by small study populations. The aim of this study was to establish the impact of the operative approach (laparoscopic or open) on outcomes after ileocolic resection for Crohn's disease.

METHOD

Ileocolic resections for Crohn's disease were identified using Current Procedural Terminology (CPT) and International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) codes from the National Surgical Quality Improvement Program (NSQIP) database (2005-2009). Complications were categorized as major (organ system damage and systemic sepsis) or minor (incisional and urinary infections). Multivariate 30-day outcomes and length of stay were determined using linear models adjusting for patient characteristics, comorbidities and operative approach.

RESULTS

Of 1917 ileocolic resections, 644 (34%) were performed laparoscopically. At baseline, the open group was significantly older, had more comorbidities, higher American Society of Anesthesiology (ASA) classes, and more intra-operative transfusions (all variables, P<0.05). On multivariate analysis, laparoscopic ileocolic resections were associated with a decrease in major (OR=0.629, 95% CI: 0.430-0.905, P=0.014) and minor (OR=0.576, 95% CI: 0.405-0.804, P=0.002) complications compared with open resections. Laparoscopy was associated with a significant reduction in adjusted length of stay compared with the open approach (-1.08±0.29 days, P=0.0002).

CONCLUSION

After adjusting for comorbidities and perioperative factors, such as preoperative sepsis, higher ASA class and higher transfusion rates in the open group, laparoscopic ileocolic resection for Crohn's disease was found to be a safer choice than the open approach, resulting in fewer complications and length of stay. All other things being equal, such patients should be offered the laparoscopic approach as a first-choice option.

It's the procedure not the patient: the operative approach is independently associated with an increased risk of complications after rectal prolapse repair

AIM

This study compares 30-day outcomes following rectal prolapse repair, examining potential surgical and patient factors associated with perioperative complications.

METHOD

Using the NSQIP database, patients with rectal prolapse were categorized by surgical approach to repair (perineal or abdominal) and abdominal cases were further subdivided by procedure (resection compared with rectopexy alone). Univariate and multivariate analyses compared major and minor complication rates between the groups.

RESULTS

Of 1275 patients, the perineal group (n=706, 55%) was older, with more comorbidity, than those undergoing an abdominal procedure. There were fewer minor (odd ratio (OR)=0.35; 95% confidence interval (CI), 0.20-0.60; P=0.0038) and major complications (OR=0.46; 95% CI, 0.31-0.80; P=0.0038) in the perineal compared with the abdominal cohort. There was a significant increase in major complications amongst patients undergoing a resection compared with rectopexy only (OR=2.15; 95% CI, 1.10-4.41; P=0.0299). There was no difference in major complications between abdominal rectopexy and a perineal approach, but the latter had a lower chance of minor complications (OR=0.47; 95% CI, 0.24-0.94; P=0.0287).

CONCLUSION

A perineal approach is safer than an abdominal approach to the treatment of rectal prolapse. Regarding an abdominal operation, rectopexy has fewer major complications than resection.