Predicting fluid responsiveness in children: a systematic review.

BACKGROUND: Administration of fluid to improve cardiac output is the mainstay of hemodynamic resuscitation. Not all patients respond to fluid therapy, and excessive fluid administration is harmful. Predicting fluid responsiveness can be challenging, particularly in children. Numerous hemodynamic variables have been proposed as predictors of fluid responsiveness. Dynamic variables based on the heart-lung interaction appear to be excellent predictors of fluid responsiveness in adults, but there is no consensus on their usefulness in children. METHODS: We systematically reviewed the current evidence for predictors of fluid responsiveness in children. A systematic search was performed using PubMed (1947-2013) and EMBASE (1974-2013). Search terms included fluid, volume, response, respond, challenge, bolus, load, predict, and guide. Results were limited to studies involving pediatric subjects (infant, child, and adolescent). Extraction of data was performed independently by 2 authors using predefined data fields, including study quality indicators. Any variable with an area under the receiver operating characteristic curve that was significantly above 0.5 was considered predictive. RESULTS: Twelve studies involving 501 fluid boluses in 438 pediatric patients (age range 1 day to 17.8 years) were included. Twenty-four variables were investigated. The only variable shown in multiple studies to be predictive was respiratory variation in aortic blood flow peak velocity (5 studies). Stroke volume index, stroke distance variation, and change in cardiac index (and stroke volume) induced by passive leg raising were found to be predictive in single studies only. Static variables based on heart rate, systolic arterial blood pressure, preload (central venous pressure, pulmonary artery occlusion pressure), thermodilution (global end diastolic volume index), ultrasound dilution (active circulation volume, central blood volume, total end diastolic volume, total ejection fraction), echocardiography (left ventricular end diastolic area), and Doppler (stroke volume index, corrected flow time) did not predict fluid responsiveness in children. Dynamic variables based on arterial blood pressure (systolic pressure variation, pulse pressure variation and stroke volume variation, difference between maximal or minimal systolic arterial blood pressure and systolic pressure at end-expiratory pause) and plethysmography (pulse oximeter plethysmograph amplitude variation) were also not predictive. There were contradicting results for plethymograph variation index and inferior vena cava diameter variation. CONCLUSIONS: Respiratory variation in aortic blood flow peak velocity was the only variable shown to predict fluid responsiveness in children. Static variables did not predict fluid responsiveness in children, which was consistent with evidence in adults. Dynamic variables based on arterial blood pressure did not predict fluid responsiveness in children, but the evidence for dynamic variables based on plethysmography was inconclusive.

Emergence delirium in children: a randomized trial to compare total intravenous anesthesia with propofol and remifentanil to inhalational sevoflurane anesthesia.

BACKGROUND: Emergence delirium (ED) refers to a variety of behavioral disturbances commonly seen in children following emergence from anesthesia. Vapor-based anesthesia with sevoflurane, the most common pediatric anesthetic technique, is associated with the highest incidence of ED. Propofol has been shown to reduce ED, but these studies have been methodologically limited. OBJECTIVE: To conduct a randomized-controlled trial comparing the incidence of ED in children following sevoflurane (SEVO) anesthesia and propofol-remifentanil total intravenous anesthesia (TIVA). METHODS: One hundred and twelve children, ASA I-II, aged ≥ 2 and ≤ 6 years, undergoing strabismus repair, were assigned to receive TIVA (intravenous induction and maintenance of anesthesia with propofol and remifentanil) or SEVO (inhalational induction and maintenance of anesthesia with sevoflurane). Parent-child induction behavior was scored using the Perioperative Adult Child Behavior Interaction Scale (PACBIS). Postoperatively, ED was assessed by a masked investigator using the Pediatric Anesthesia Emergence Delirium (PAED) Scale and pain using the Face, Legs, Activity, Cry, Consolability (FLACC) Scale every 5 min. RESULTS: Data are reported for 94 subjects. Incidence of ED was higher with SEVO (38.3% vs 14.9%, P = 0.018). There was no difference in the median PACBIS score. A higher FLACC score was seen with SEVO (median 3 vs 1, P = 0.033). Subjects experiencing ED had higher FLACC scores vs those unaffected by ED (median 7 vs 1, P < 0.0001). CONCLUSION: There was a lower incidence of ED after TIVA. Both intravenous and inhalational inductions were similarly well-tolerated. The use of TIVA was associated with reduced postoperative pain as measured using FLACC scores.

Hypertonic saline reduces skeletal muscle injury and associated remote organ injury following ischemia reperfusion injury.

BACKGROUND AND PURPOSE: Pharmacological modulation of skeletal muscle reperfusion injury after traumaassociated ischemia may improve limb salvage rates and prevent the associated systemic sequelae. Resuscitation with hypertonic saline restores the circulating volume and has favorable effects on tissue perfusion and blood pressure. We evaluated the effects of treatment with a bolus of hypertonic saline on skeletal muscle ischemia reperfusion (IR) injury and the associated end-organ injury. METHODS: Adult male Sprague-Dawley rats (n = 27) were randomized into 3 groups: (1) a control group, (2) an IR group treated with normal saline, and (3) an IR group treated with hypertonic saline. Bilateral hindlimb ischemia was induced by application of a rubber band proximal to the level of the greater trochanters for 2.5 h. The treatment groups received either normal saline (4 mL/kg) or hypertonic saline (4 mL/kg) prior to tourniquet release. Following 12 h of reperfusion, the tibialis anterior muscle was dissected and muscle function was assessed electrophysiologically. The animals were then killed, and skeletal muscle and lung tissue were harvested for evaluation. RESULTS: Hypertonic saline significantly attenuated skeletal muscle reperfusion injury, as shown by reduced myeloperoxidase content, wet-to-dry ratio, and electrical properties of skeletal muscle. There was a corresponding reduction in lung injury, as demonstrated by reduced myeloperoxidase content and reduced wet-to-dry ratio. INTERPRETATION: Treatment with hypertonic saline attenuates skeletal muscle ischemia reperfusion injury and its associated systemic sequelae.

Pravastatin attenuates tourniquet-induced skeletal muscle ischemia reperfusion injury.

BACKGROUND: Revascularization of a limb following prolonged ischemia results in substantial skeletal muscle injury. Statins play a well-understood role in the treatment of hypercholesterolemia but are also known to have anti-inflammatory properties. The purpose of this study was to examine the effects of pravastatin pre-treatment in the setting of skeletal muscle ischemia reperfusion injury (IRI). METHODS: Adult male Sprague Dawley rats (n = 27) were randomized into 3 groups: control group, I/R group, IR group pre-treated with pravastatin. Bilateral hind-limb ischemia was induced by rubber band application proximal to the level of the greater trochanters for 2.5 h. Treatment groups received normal saline in equal volumes prior to tourniquet release. Following 12 h reperfusion, the tibialis anterior muscle was dissected and muscle function assessed electrophysiologically by electrical field stimulation. The animals were then killed and skeletal muscle harvested for evaluation. RESULTS: We found that pre-treatment with pravastatin reduces the tissue oxidative damage and edema associated with skeletal muscle reperfusion injury. Skeletal muscle injury, measured by edema, leucosequestration and electrical properties were significantly lower with pravastatin pre-treatment compared to the non-treated group. INTERPRETATION: We feel that pravastatin pre-treatment may be a potential therapeutic intervention for skeletal muscle ischemia reperfusion injury in the clinical setting.