Predictors of Arterial Blood Pressure Control During Deliberate Hypotension with Sodium Nitroprusside in Children

Abstract

Background Sodium nitroprusside (SNP) is used to decrease arterial blood pressure (BP) during certain surgical procedures. There are limited data regarding efficacy of BP control with SNP. There are no data on patient and clinician factors that affect BP control. We evaluated the dose-response relationship of SNP in infants and children undergoing major surgery and performed a quantitative assessment of BP control. Methods One hundred fifty-three subjects at 7 sites received a blinded infusion followed by open-label SNP during operative procedures requiring controlled hypotension. SNP was administered by continuous infusion and titrated to maintain BP control (mean arterial BP [MAP] within ±10% of clinician-defined target). BP was recorded using an arterial catheter. Statistical Process Control methodology was used to quantify BP control. A multivariable model assessed the effects of patient and procedural factors. Results BP was controlled an average 45.4% (SD 23.9%, 95% CI 41.5%-49.18%) of the time. Larger changes in infusion rate were associated with worse BP control (7.99% less control for 1 mcg•kg−•min− increase in average titration size, p=0.0009). A larger difference between a patient's baseline and target MAP predicted worse BP control (0.93% worse control per 1 mmHg increase in MAP difference, p=0.0013). Both effects persisted in multivariable models. Conclusions : SNP was effective in reducing BP. However, BP was within the target range less than half of the time. No clinician or patient factors were predictive of BP control, although two inverse relationships were identified. These relationships require additional study and may be best coupled with exposure-response modeling to propose improved dosing strategies when using SNP for controlled hypotension in the pediatric population.

Managing Shiga Toxin-Producing E. coli Using Statistical Process Control Charts for Routine Health and Production Monitoring in Pig Farming

“…In practice, the single farm adopting a real-time monitoring of its productive process might be able to early recognize out of control signals, but also to calculate a new PCL and limits when the chart signals a sustained change via the tests (e.g., tests 2 and 3), reflecting a new level of performance. Since the charts are set up with an upper as well as a lower control limit, it is possible to not only give a signal when the process turns in the unfavorable direction, but also to give a positive signal when the process shifts in the desired direction ( 20 ), for example after batches 47–49 in present study (positive for test 2). This allow the farm to monitor the own results and shift the own limits even when the method is introduced for the first time in a period that cannot be defined in control, differently from the Period 1 available in the present study.…”

“…The I-chart displays the individual data and monitors mean and shift in the process while the variation is monitored by the MR-chart ( 14 ). In human healthcare, SPC charts have been used to discriminate between changes that yield improvement and those that do not, by visualization and analysis of the performance of a process over time [including biological processes such as blood pressure homoeostasis or organizational processes such as patient care in a hospital; ( 20 , 21 )], sometimes in real time. In the swine sector, SPC charts were used to reveal changes in a production process after Porcine Reproductive and Respiratory Syndrome outbreak or vaccination ( 22 , 23 ).…”

A hemodynamic model to guide blood pressure control during deliberate hypotension with sodium nitroprusside in children

“…Based on the simulation exercise, the reduction in MAP following SNP administration can be managed with a small number of dose adjustments. While hemodynamic improvement should be considered in conjunction with other meaningful clinical outcomes when assessing the overall efficacy of SNP, it is clear that a model-based approach may improve the tendency to “over-adjust” or too frequently titrate SNP in response to real time MAP (Spielberg et al, 2014 ). Parallel efforts to discriminate superior dosing practices in this investigation revealed much variability in dosing practice, with hemodynamic control well-outside of anticipated patient management expectations (Spielberg et al, 2014 ).…”