Absence of Tachycardia During Hypotension in Children Undergoing Craniofacial Reconstruction Surgery
ABSTRACT Tachycardia is a baroreceptor-mediated response to hypotension. Heart rate (HR) behavior in the setting of hypotension in anesthetized children is not well characterized. We conducted this study to assess the relationship between HR and hypotension in a population of anesthetized children experiencing massive blood loss. Our primary hypothesis was that HR would be increased with the onset of hypotension associated with hypovolemia in comparison with time points without hypotension.
We performed a query of our prospective craniofacial perioperative registry for children younger than 24 months who underwent cranial vault reconstruction surgery. Demographic and perioperative data were extracted, and the intraoperative blood loss was calculated. Vital signs were extracted from our computerized anesthesia record and analyzed. Hypotension was defined as a mean arterial blood pressure <40 mm Hg for at least 3 computerized anesthesia record entries (captured every 15 seconds). The preoperative HR, the average HR over the entire intraoperative period, the HR at the onset of hypotension, and the HR 5 minutes before and 5 minutes after the hypotensive episode were compared.
The registry query yielded data from 57 procedures. There were 29 episodes of hypotension occurring in 10 subjects. There was no significant difference in HR at the onset of hypotension (when mean arterial blood pressure decreased below 40 mm Hg) in comparison with the preoperative HR, the average intraoperative HR, or in comparison with 5 minutes before and 5 minutes after the episode of hypotension.
In this study of anesthetized children younger than 24 months undergoing surgery with massive blood loss, hypotension was not associated with an increased HR. HR does not appear to be a useful indicator of hypovolemia in this population.
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ABSTRACT: BACKGROUND:Massive hemorrhage during craniofacial surgery is common and often results in hypovolemia and hypotension. We conducted this study to assess the effect of the addition of routine central venous pressure (CVP) monitoring on the incidence of intraoperative hypotension and to evaluate the relationship between CVP and hypotension in this population.METHODS:Data from our prospective craniofacial perioperative registry for children 6 to 24 months of age undergoing cranial vault reconstruction with CVP monitoring were compared with data from a historical cohort without CVP monitoring. The incidence and duration of hypotension in the 2 cohorts were compared. In the cohort of subjects with CVP monitoring who experienced hypotension, CVP at the onset of hypotension (T0) was compared with CVP 5 minutes before (T - 5) and 5 minutes after (T + 5) the onset of hypotension and with the baseline CVP. The amount of time spent at various CVP levels below the baseline, and the associated incidence of hypotension were also determined.RESULTS:Data from 57 registry subjects were compared with data from 115 historical cohort subjects. The median total duration of hypotension in subjects experiencing hypotension was 278 seconds in the CVP cohort versus 165 seconds in the historical cohort; the median difference was 98 seconds (95% confidence interval [CI], -45 to 345 seconds). The incidence of hypotension was 18% in the CVP cohort versus 21% in the historical cohort; the difference in the incidence of hypotension was -3% (95% CI, -10% to 15%). Analysis using a linear mixed effects model showed a significant decrease in CVP from T - 5 to T0 (95% CI, -0.9 to -2.2 mm Hg), a significant increase in CVP from T0 to T + 5 (95% CI, 1.0-2.4 mm Hg), no significant difference in CVP between T - 5 and T + 5 (95% CI, -0.9 to 0.9 mm Hg), and a significant decrease in CVP from baseline to T0 (95% CI, -3.4 to -2.1 mm Hg). CVP at T0 was less than the baseline CVP in 97% of hypotensive episodes. When all cases were examined, CVP was ≥3 mm Hg below the baseline for 16% of the total time studied, with an associated incidence of hypotension of 2%.CONCLUSIONS:The implementation of routine CVP monitoring was not associated with a decreased incidence and likely was not associated with a decreased duration of hypotension in this population experiencing massive hemorrhage. Hypotension was associated with a decrease in CVP, and resolution of hypotension was associated with an increase in CVP to prehypotensive levels. However, significant decreases in CVP below the baseline were common and usually not associated with hypotension. The routine use of CVP monitoring in these children is of questionable utility as a means to decrease the incidence and duration of hypotension.Anesthesia and analgesia 01/2013; 116(2). DOI:10.1213/ANE.0b013e31827008e6 · 3.42 Impact Factor
Article: Pediatric Perioperative Life Support[Show abstract] [Hide abstract]
ABSTRACT: Pediatric advanced life support training and guidelines are typically designed for first-responders and out-of-hospital resuscitation. Guidelines and scenarios that are more applicable to the perioperative environment would be beneficial for anesthesiologists. The goal of this article is to review resuscitation of pediatric patients during the perioperative period. We use a format that focuses on preresuscitation preparation, resuscitation techniques, and postresuscitation management in the perioperative period. In an effort to provide information of maximum benefit to anesthesiologists, we include common pediatric perioperative arrest scenarios with detailed description of their management. We also provide a section on postresuscitation management and review the techniques for maintaining the child's hemodynamic and metabolic stability. Finally, 3 appendices are included: an example of an intraoperative arrest record that provides feedback for interventions; a table of key medications for pediatric perioperative resuscitation; and a review of defibrillator use and simulation exercises to promote effective defibrillation.Anesthesia and analgesia 09/2013; 117(4). DOI:10.1213/ANE.0b013e3182a1f3eb · 3.42 Impact Factor
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ABSTRACT: The safety of anesthesia has improved greatly in the past three decades. Standard perioperative monitoring, including pulse oximetry, has practically eliminated unrecognized arterial hypoxia as a cause for perioperative injury. However, most anesthesia-related cardiac arrests in children are now cardiovascular in origin, and standard monitoring is unable to detect many circulatory abnormalities. Near-infrared spectroscopy provides noninvasive continuous access to the venous side of regional circulations that can approximate organ-specific and global measures to facilitate the detection of circulatory abnormalities and drive goal-directed interventions to reduce end-organ ischemic injury.Pediatric Anesthesia 11/2013; 24. DOI:10.1111/pan.12301 · 1.74 Impact Factor