A sensitive multicolor fluorescence sensing strategy for chlorotetracycline based on bovine serum albumin-stabilized copper nanocluster.

Fluorescent probes with on-site visual detection function have received extensive attention in the detection of chlortetracycline (CTC), which was widely used in aquaculture and animal husbandry. Copper nanoclusters (Cu NCs) with excellent optical properties were prepared using bovine serum albumin (BSA) as a template, and a multicolor fluorescence strategy based on BSA-stabilized Cu NCs (BSA-Cu NCs) for detecting CTC was proposed. BSA-Cu NCs had a red emission at 640 nm. After the addition of CTC, the red emission of BSA-Cu NCs gradually decreased for internal filtering effect, while the green emission of CTC was significantly enhanced under the sensitization of BSA. This simple sensing process can be achieved in real time by directly mixing the target sample with BSA-Cu NCs, and the detection limit (LOD) of the system for CTC was 12.01 nM. Based on this sensing strategy, a fluorescence film sensing detection platform was constructed to achieve ultra-fast detection of CTC within 30 s. This work provided a fluorescent film sensor with the advantages of portability, ultra-fast and low cost, which provided a feasible alternative for on-site ultra-fast screening of CTC.

Highly selective and multicolor ultrasensitive assay of dipicolinic acid: The integration of terbium(III) and gold nanocluster.

A novel multicolor fluorescent nano-probe based on the hybridization of Tb3+ ion with gold nanoclusters (Au NCs) was synthesized to monitor and on-site visual assay of 2,6-pyridinedicarboxylic acid (DPA), a biomarker of bacterial spores. DPA can replace the water molecule in the center of Tb3+ and strongly coordinate with Tb3+ based on the analyte-triggered antenna effect. Simultaneously, the red fluorescence of Au NCs is not influenced after addition of DPA and can be used as steady inside fluorescence reference channel to measure background noise. On this basis, the multicolor fluorescence nano-probe based on Tb3+-doped Au NCs for fast analysis of DPA was fabricated. The linear range of this method is 0 to 12.5 µM and the limit of detection is 3.4 nM, which is well below the quantity of DPA concentration of 60 µM released by the spore transmission dose of anthrax infection. The proposed multicolor fluorescence nano-probe was successfully detecting DPA in actual sample with good sensitivity and specificity. In addition, the visual paper-based nano-probe is designed to detect DPA by using the color scanning application of smart phone. This developed platform possesses abroad application prospects with advantages of effective, convenient carrying, simple operation, good selectivity and repeatability.

Multicolor fluorescence assay of tetracycline: lanthanide complexed amino clay loaded with copper nanoclusters.

A multicolor fluorescent nanoprobe has been prepared by loading bovine serum albumin-stabilized copper nanoclusters (BSA-Cu NCs) onto amino clay (AC) and grafting Eu3+ with auxiliary ligand citric acid (Cit). Tetracycline (TC) can coordinate with Eu3+ by ß-diketone structure and transfer energy to Eu3+ through antenna effect. When the concentration of TC is in the range 0 to 13 µM, the blue emission intensity of BSA-CuNCs is basically unchanged, and the red emission of Eu3+ is remarkably enhanced due to the coordination with TC. The emission color gradually changes from blue to red under UV lamp (λ = 365 nm). However, when the TC concentration is in the range 13 to 350 µΜ, the internal amino acid residues of BSA sensitize TC, and the emission color gradually changed from red to green. The nanoprobe has rich color, is simple to prepare, portable, and provide a wide detection range. The limit of detection (LOD) is 3.04 nM, which could be used for real-time visual analysis of trace TC in actual samples (lake water, milk, honey, and bovine serum albumin). In addition, a visual test paper has been designed and combined with the color scanning APP of a smartphone to complete the qualitative and semi-quantitative test of TC. BSA-Cu NCs were loaded on amino clay and graft Eu3+ to establish ratiometric fluorescent nanoprobe for TC detection. With the increase of TC concentration, the emission color under 365 nm UV lamp gradually changed from blue to red and then to green, and the color changed obviously and can be observed by the naked eye. The visual test paper and smartphone application detection sensor were developed to realize rapid, convenient, real-time, and visual detection of TC in actual samples.

Clinical characteristics of pediatric intussusception and predictors of bowel resection in affected patients.

Background: Surgery is required for the treatment of intussusception when enema reduction is unsuccessful, or when the patient develops peritonitis, bowel perforation, or intestinal damage. We aimed to evaluate the clinical and laboratory parameters that may be used to predict the need for bowel resection in children with intussusception. Methods: This observational retrospective study included children who were admitted to the pediatric emergency department with intussusception. Univariate and multivariate logistic regression models were used to evaluate factors associated with bowel resection. Results: In total, 584 children with intussusception were admitted to the pediatric emergency department; 129 of these children underwent surgery. Multivariate analysis revealed the following independent predictors of bowel resection for intussusception: symptoms for at least 2 days before surgery (OR = 6.863; p = 0.009), long intussusception (OR = 5.088; p = 0.014), pathological lead point (OR = 6.926; p = 0.003), and intensive care unit admission (OR = 11.777; p = 0.001) were factors independently associated with bowel resection. Conclusion: Symptoms for at least 2 days before surgery, long intussusception, pathological lead, and intensive care unit admission were predictors of bowel resection in children with intussusception. These findings can be used to identify patients at high risk of needing surgery and bowel resection.

Platelet CD40L Expression Response to Mixing of pRBCs and Washed Platelets but no Causality Association between Platelet ROS Generation and CD40L Expression: An In Vitro Study.

Platelets play a role in transfusion reaction via reactive oxygen species (ROS) generation and CD40 ligand (CD40L) expression. In this study, we aimed to test the hypothesis that the mixing of packed red blood cells (pRBCs) and washed platelets has a causal effect on platelet ROS generation and CD40L expression. Thus, a better understanding of this causality relationship may help interrupt the chain of events and avoid an uncontrollable transfusion reaction. We simulated transfusion in vitro by mixing pRBCs and washed platelets. Donor cross-matched stored pRBCs) from our blood bank and recipient whole blood from patients undergoing coronary artery bypass graft surgery prepared into washed platelets were used. Briefly, donor pRBCs were added to washed recipient platelets to form 1%, 5%, or 10% (v/v) mixtures. The mixed blood sample was used to determine platelet ROS generation (dichlorofluorescein fluorescence levels) and CD40L expression. The effect of antioxidants (20 mM glutamine and 20 mM dipeptiven) on ROS generation and CD40L expression was also evaluated. Platelet ROS generation was not significantly associated with the mixing of pRBCs and washed platelets (p = 0.755), glutamine treatment (p = 0.800), or dipeptiven treatment (p = 0.711). The expression of CD40L by platelets increased significantly (p < 0.001), and no significant difference was noted after treatment with glutamine (p = 0.560) or dipeptiven (p = 0.618). We observed that the mixing pRBCs and washed platelets had no effect via ROS, whereas CD40L could directly induce transfusion reactions. Furthermore, platelets did not causally express ROS or CD40L after being mixed with pRBCs. Although antioxidants are more accessible than anti-CD40L antibodies, platelet ROS may not serve as a therapeutic target for antioxidants. Nevertheless, CD40L expression may be a valuable therapeutic target for managing transfusion reactions.

Evaluation of the Preventive Effects of Fish Oil and Sunflower Seed Oil on the Pathophysiology of Sepsis in Endotoxemic Rats.

Sepsis causes platelet activation, systemic inflammation, organ dysfunction, and mortality. Endotoxins play an important role in the manifestation of the symptoms of septic shock. As fish oil exert well known anti-inflammatory effects and sunflower seed oil exert less anti-inflammatory properties than fish oil, both oils are widely used. We aimed to test the hypothesis that dietary supplementation of these two oils before endotoxemia modulates the consequences of illness. Nine- to ten-week-old male Wistar rats (N = 55) were divided into four groups: group A (N = 6), control; group B (N = 17), saline + lipopolysaccharide (endotoxin); group C (N = 17), fish oil + lipopolysaccharide; and group D (N = 15), sunflower seed oil + lipopolysaccharide. After 28 days of feeding the designated diet, the rats in all groups were intraperitoneally injected with lipopolysaccharide. After 24 h, survival rate, endotoxemia severity, levels of platelet activation markers, organ function and biochemical variables were evaluated. Platelet-leukocyte aggregation was significantly high in group C (p = 0.005), and platelet-monocyte aggregation was significantly high in groups C (p = 0.003) and D (p = 0.016) than in group B. The survival rate, endotoxemia severity, expression of platelet P-selectin, CD40L, and TLR4, pulmonary function, renal function, liver function, or biochemical variables did not significantly differ among groups B, C, and D. Instead of an anti-inflammatory effect, the dietary supplementation of fish and sunflower seed oils exerted a pro-inflammatory effect, especially via platelet-monocyte aggregation, suggesting a rebound effect of the dietary supplementation of the oils. The oils did not affect other inflammatory platelet markers or improve the outcome of endotoxemic rats. However, further studies are required to understand the underlying mechanisms of such effects and to elaborate the clinical significance of these findings.

Platelet Toll-like Receptor 4-Related Innate Immunity Potentially Participates in Transfusion Reactions Independent of ABO Compatibility: An Ex Vivo Study.

The role of platelet TLR4 in transfusion reactions remains unclear. This study analyzed platelet TLR4 and certain damage-associated molecular patterns (DAMPs) and evaluated how ABO compatibility affected TLR4 expression after a simulated ex vivo transfusion. A blood bank was the source of donor red blood cells. Blood from patients undergoing cardiac surgery was processed to generate a washed platelet suspension to which the donor blood was added in concentrations 1, 5, and 10% (v/v). Blood-mixing experiments were performed on four groups: a 0.9% saline control group (n = 31); a matched-blood-type mixing group (group M, n = 20); an uncross-matched ABO-specific mixing group (group S, n = 20); and an ABO-incompatible blood mixing group (group I, n = 20). TLR4 expression in the platelets was determined after blood mixing. We evaluated levels of TLR4-binding DAMPs (HMGB1, S100A8, S100A9, and SAA), lipopolysaccharide-binding protein, and endpoint proteins in the TLR4 signaling pathway. In the M, S, and I groups, 1, 5, and 10% blood mixtures significantly increased TLR4 expression (all p < 0.001) in a concentration-dependent manner. Groups M, S, and I were not discovered to have significantly differing TLR4 expression (p = 0.148). HMGB1, S100A8, and S100A9 levels were elevated in response to blood mixing, but SAA, lipopolysaccharide-binding protein, TNF-α, IL-1ß, and IL-6 levels were not. Blood mixing may elicit innate immune responses by upregulating platelet TLR4 and DAMPs unassociated with ABO compatibility, suggesting that innate immunity through TLR4-mediated signaling may induce transfusion reactions.

Clinical Features and Risk Factors for Mortality in Children With Acute Encephalitis Who Present to the Emergency Department.

Acute encephalitis is an important pediatric emergency that tends to be associated with neurological morbidity, critical illness, and mortality. Few data have specifically focused on evaluating various early clinical parameters in the pediatric emergency department as candidate predictors of mortality. The present retrospective study assessed the clinical, laboratory, and neuroimaging findings of children with acute encephalitis who presented to the emergency department. Of 158 patients diagnosed with encephalitis, 7 (4.4%) had mortality. Compared to the survivors, a multivariate analysis revealed that an initial Glasgow Coma Scale score ≤ 5 (odds ratio [OR]: 8.3, P = .022), acute necrotizing encephalitis (OR: 12.1, P = .01), white blood count level ≤ 5.2 × 109 cells/L (OR: 28.7, P < .001), aspartate aminotransferase level > 35 U/L (OR: 14.3, P = .022), and influenza A infection (OR: 7.7, P = .027) were significantly associated with mortality. These results indicate that the early recognition of preliminary clinical features and the development of more specific etiologies for encephalitis are important for early treatment strategies.

Two head positions for orotracheal intubation with the trachway videolight intubating stylet with manual in-line stabilization: A randomized controlled trial.

BACKGROUND: The Trachway Videolight Intubating Stylet is a video-assisted system with a rigid but malleable intubating stylet that facilitates endotracheal intubation. Minimizing cervical spine movement with manual in-line stabilization is essential for patients with cervical spine injuries such as multiple trauma. However, the intubation time of the Trachway Videolight Intubating Stylet and complications associated with intubation in patients with manual in-line stabilization in the neutral-head and head-lift positions remain unclear. METHODS: Patients (20-80 years old) who were scheduled to undergo surgery that required general anesthesia with tracheal intubation were randomly allocated to either a neutral-head (n = 62) or a head-lift position (n = 62) group. Manual in-line stabilization was performed to limit cervical spine mobility. We aimed to evaluate orotracheal intubation time and success rate in these 2 positions with the Trachway Videolight Intubating Stylet. RESULTS: Intubation was faster in the head-lift than in the neutral-head position (20 ±â€Š10 and 25 ±â€Š13 seconds, respectively, P = .000); intubation was equally successful in the 2 positions (96.8% vs 96.8%). Responses to intubation did not differ between positions (heart rate, P = .142; visual analog scale scores for throat soreness, P = .54). The only significant predictor of intubation time was the body mass index in the head-lift position group (P = .005). CONCLUSIONS: Intubation using the Trachway Videolight Intubating Stylet with manual in-line stabilization is faster in the head-lift position, and therefore preferable. However, if the head-lift position is not suitable, the neutral-head position is a sensible alternative, with comparable intubation success rate, heart rate change, and postoperative throat soreness.

Association of developing childhood epilepsy subsequent to febrile seizure: A population-based cohort study.

PURPOSE: Epilepsy is an important neurological condition that frequently associated with neurobehavioral disorders in childhood. Our aim was to identify the risk of developing epilepsy subsequent to febrile seizure and the association between epilepsy risk factors and neurobehavioral disorders. SUBJECTS AND METHODS: This longitudinal population-based cohort data included 952 patients with a febrile seizure diagnosis and 3808 age- and sex-matched controls. Participants were recruited for the study from 1996 to 2011, and all patients were followed up for maximum 12.34 years. RESULTS: The association of epilepsy was significantly higher (18.76-fold) in individuals that experienced febrile seizure compared to controls. Further, of those individuals who experienced febrile seizure, the frequency of subsequent development of epilepsy was 2.15-fold greater in females, 4.846-fold greater in patients with recurrent febrile seizure, and 11.26-fold greater patients with comorbid autism. CONCLUSIONS: Our study showed that being female, comorbid autism with febrile seizure and recurrent febrile seizure had an increased association with development of epilepsy. Increased recognition the association for epilepsy might be warranted in those febrile seizure children with certain characteristics.

Clinical characteristic and risk factors of recurrent sexual abuse and delayed reported sexual abuse in childhood.

Child sexual abuse (CSA) is a global problem that affects children of all ages, and the evaluation of these victims by psychologic and gynecologic experts in pediatric emergency departments is an important issue. Few data are available on the characteristics of children admitted to pediatric emergency department with recurrent CSA and delayed reported CSA. The aim of the present study was to describe the clinical features of, and risk factors for, recurrent CSA and delayed reported CSA. The study retrospectively analyzed victims of CSA who were admitted to a pediatric emergency department. Chi-square tests and univariate analyses were performed to assess the risk factors of recurrent or delayed reported CSA. Of the 91 CSA cases, 32 (35.2%) were recurrent assaults. Of the 70 cases recorded the duration of the event, 22 (31.4%) were delayed report cases. Comparisons of the non-recurrent and recurrent CSA assault groups revealed a significant increase in comorbidities (odds ratio [OR]: 4.46, 95% confidence interval [CI]: 1.54-12.93), acute psychiatric problems (OR: 3.18, CI: 1.26-8.06), attempted suicide (OR: 4.23, CI: 1.28-13.99), and the need for treatment with antipsychotic medications (OR: 5.57, CI: 1.37-22.65). Compared with non-delayed reported cases, the delay reported cases of CSA were significantly more likely to have anxiety (P < .05). The CSA victims in the present study exhibited acute medical and/or psychosocial problems, which indicate that pediatric emergency professionals have a responsibility to look for and recognize particular characteristics in these victims.

Blood Mixing Upregulates Platelet Membrane-Bound CD40 Ligand Expression In Vitro Independent of Abo Compatibility.

Platelets play a central role in the inflammation response via CD40 ligand (CD40L) expression, which may lead to transfusion reactions. The precise role of platelet CD40L-mediated inflammation in transfusion reactions is unclear. Therefore, we assessed the effects of in vitro blood mixing on platelet CD40L expression. In addition, we examined the effect of ABO compatibility on CD40L expression. Donor-packed red blood cells were acquired from a blood bank, and recipient blood was obtained from patients undergoing cardiac surgery and prepared as washed platelets. Donor blood was mixed with suspended, washed recipient platelets to obtain a final mixing ratio of 1%, 5%, or 10% (vol/vol). The blood mixtures were divided into three groups: group M, cross-matched blood-type mixing (n = 20); group S, ABO type-specific uncross-matched blood (n = 20); and group I, ABO incompatibility (not ABO type-specific blood and not process cross-matched) mixing (n = 20). The blood mixtures were used to detect platelet membrane-bound CD40L expression by flow cytometry. Blood mixing resulted in an increase in CD40L expression in group M (P < 0.001), group S (P < 0.001), and group I (P < 0.001). CD40L expression after blood mixing potentially led to a transfusion reaction in each of the groups. There were no differences in CD40L expression among the three groups (P = 0.988) correlated with ABO compatibility or incompatibility. This indicates that the reactions between red blood cell surface antigens and plasma antibodies do not play a role in the induction of CD40L expression.

Impact of Blood Mixing and ABO Compatibility on Platelet-Leukocyte Aggregations and Platelet P-Selectin Expression: An in Vitro Study.

Effects of blood transfusions on platelet- and leukocyte-related inflammation are unclear. We simulated transfusion using in vitro blood mixing to evaluate platelet-leukocyte aggregations (PLA) and platelet P-selectin expression, and the mechanism of PLA. Donor packed red blood cells (pRBCs) were obtained from a blood bank. Recipient whole blood samples were obtained from patients undergoing cardiac surgery. Blood sample mixtures were divided into four groups: group M, cross-matched blood type mixing; group O, donor type O with other blood type mixing (A, B, or AB); group S, ABO type-specific uncross-matched blood mixing; and group I, ABO incompatibility mixing. Donor pRBCs were added to recipient blood to reach 1%, 5%, and 10% (vol/vol) concentrations. Blood sample mixtures were analyzed to determine the PLA; P-selectin expression; and leukocyte CD11a, CD11b, and CD18 subunits of integrin expression. Analysis of variance tests were used to analyze differences. PLA significantly increased only in groups O and I (P = 0.003 and P < 0.001). Subpopulations of leukocytes significantly increased in all groups. There were no significant differences among the four groups (P = 0.578) in PLA increase. Although there was no significant effect on P-selectin expression (P = 1.000) and leukocyte CD11a and CD18 expression (P = 0.999, P = 0.422) within and between the groups, there was an increase in CD11b expression (P = 0.018). Blood mixing can increase PLA, especially in platelet-neutrophil and platelet-monocyte aggregations, possibly through nonhemolytic reactions. The CD11b integrin with CD18 may play a role in the formation of PLA.

Epidemiology and clinical analysis of critical patients with child maltreatment admitted to the intensive care units.

Children with abuse who are admitted to the intensive care unit (ICU) may have high mortality and morbidity and commonly require critical care immediately. It is important to understand the epidemiology and clinical characteristics of these critical cases of child maltreatment.We retrospectively evaluated the data for 355 children with maltreatments admitted to the ICU between 2001 and 2015. Clinical factors were analyzed and compared between the abuse and the neglect groups, including age, gender, season of admission, identifying settings, injury severity score (ISS), etiologies, length of stay (LOS) in the ICU, clinical outcomes, and mortality. In addition, neurologic assessments were conducted with the Pediatric Cerebral Performance Category (PCPC) scale.The most common type of child maltreatments was neglect (n = 259), followed by physical abuse (n = 96). The mean age of the abuse group was less than that of the neglect group (P < .05). Infants accounted for the majority of the abuse group, and the most common etiology of abuse was injury of the central nervous system (CNS). In the neglect group, most were of the preschool age and the most common etiologies of abuse were injury of the CNS and musculoskeletal system (P < .001). The mortality rate in the ICU was 9.86%. The ISS was significantly associated with mortality in both the 2 groups (both P < .05), whereas the LOS in the ICU and injuries of the CNS, musculoskeletal system, and respiratory system were all associated with mortality in the neglect group (all P < .05). The PCPC scale showed poor prognosis in the abuse group as compared to the neglect group (P < .01).In the ICU, children in the abuse group had younger age, higher ISS, and worse neurologic outcome than those in the neglect group. The ISS was a predictor for mortality in the abuse and neglect groups but the LOS in the ICUs, injuries of the CNS, musculoskeletal system, and respiratory system were indicators for mortality in the neglect group. Most importantly, identifying the epidemiological information may provide further strategies to reduce the harm, lower the medical costs, and improve clinical care quality and outcomes in children with abuse.

Clinical Characteristics and Risk Factors for Seizures Associated With Norovirus Gastroenteritis in Childhood.

Norovirus has become increasingly recognized as causing viral gastroenteritis in children. Few data are available on the characteristics of children admitted to pediatric emergency departments with norovirus gastroenteritis and accompanying seizures. Our aim in this study was to describe the clinical features of, and risk factors for, seizures accompanying norovirus gastroenteritis. We collected 6359 stool samples from patients with gastroenteritis, of whom 1444 (22.71%) had laboratory-confirmed norovirus gastroenteritis. Of all patients, 108 (7.48%) children exhibited norovirus gastroenteritis and seizures; 49 (45.4%) were febrile, and 59 (54.6%) afebrile. The mean patient age was 2.31 ± 2.12 years; most were <5 years of age (92.6%). The afebrile group had a significantly higher incidence of 2 or more seizures than the febrile subjects ( P = .004). Early recognition and prompt treatment of convulsions associated with norovirus gastroenteritis in children are important. Future studies might explore the long-term prognoses of these patients.

Effect of External Pressure and Catheter Gauge on Flow Rate, Kinetic Energy, and Endothelial Injury During Intravenous Fluid Administration in a Rabbit Model.

The effects of intravenous (IV) catheter gauge and pressurization of IV fluid (IVF) bags on fluid flow rate have been studied. However, the pressure needed to achieve a flow rate equivalent to that of a 16 gauge (G) catheter through smaller G catheters and the potential for endothelial damage from the increased kinetic energy produced by higher pressurization are unclear. Constant pressure on an IVF bag was maintained by an automatic adjustable pneumatic pressure regulator of our own design. Fluids running through 16 G, 18 G, 20 G, and 22 G catheters were assessed while using IV bag pressurization to achieve the flow rate equivalent to that of a 16 G catheter. We assessed flow rates, kinetic energy, and flow injury to rabbit inferior vena cava endothelium. By applying sufficient external constant pressure to an IVF bag, all fluids could be run through smaller (G) catheters at the flow rate in a 16 G catheter. However, the kinetic energy increased significantly as the catheter G increased. Damage to the venous endothelium was negligible or minimal/patchy cell loss. We designed a new rapid infusion system, which provides a constant pressure that compresses the fluid volume until it is free from visible residual fluid. When large-bore venous access cannot be obtained, multiple smaller catheters, external pressure, or both should be considered. However, caution should be exercised when fluid pressurized to reach a flow rate equivalent to that in a 16 G catheter is run through a smaller G catheter because of the profound increase in kinetic energy that can lead to venous endothelium injury.

Nitrous oxide myelopathy in a pediatric patient.

OBJECTIVE: Nitrous oxide myelopathy is rare in children. We report a 16-year-old girl who presented at the pediatric emergency department with progressive ascending numbness in 4 limbs for 1 week and sensory ataxia for 4 days. The patient had frequently inhaled nitrous oxide for recreation over the preceding 3 months. Her serum vitamin B12, homocysteine, and folate levels were within normal ranges. Magnetic resonance imaging of the spinal cord T2-weighted images series showed hyperintensities in the central and dorsal cervical spinal cord section over C1 to C6 and suspicious of hyperintensities in the thoracic spinal section over T7 and T8. CONCLUSIONS: Myelopathy due to nitrous oxide should be considered in a differential diagnosis when adolescents develop neurologic symptoms after nitrous oxide inhalation abuse.

Mesenteric defect with internal herniation in the pediatric emergency department: an unusual presentation of acute abdomen.

Internal herniation is a rare cause of intestinal obstruction, especially in the emergency department. We report a child with acute abdomen resulting from transmesenteric internal herniation of the small bowel. Radiographic findings revealed gaseous distension of the bowel loops in the upper abdominal area with a paucity of gas in the lower abdomen. Operative finding showed gangrenous small bowel due to mesenteric defect with an internal herniation. The gangrenous bowel was resected and the patient was discharged with an uneventful outcome. We emphasize that early recognition of internal herniation warrants further evaluation and appropriate management.

Bilateral passive leg raising attenuates and delays tourniquet deflation-induced hypotension and tachycardia under spinal anaesthesia: a randomised controlled trial.

BACKGROUND: The pneumatic tourniquet is frequently used in total knee arthroplasty. Tourniquet deflation may result in hypotension and tachycardia caused by the rapid shift of blood volume back to the ischaemic limb and a decrease in cardiac preload. Passive leg raising (PLR) represents a 'self-volume challenge' that can result in an increase in preload. Such a PLR-induced increase in preload was hypothesised to attenuate the decrease in preload resulting from tourniquet deflation. OBJECTIVE: To evaluate the effect of PLR on hypotension and tachycardia following tourniquet deflation. DESIGN: A randomised controlled trial. SETTING: Single medical centre. PATIENTS: Seventy patients who underwent unilateral total knee arthroplasty were randomised into two groups: tourniquet deflation with PLR (n = 35) or without PLR (control group, n = 35). INTERVENTION(S): Patients in both groups were administered a single dose of plain bupivacaine for spinal anaesthesia. The pneumatic tourniquet was inflated on the thigh and the surgery was performed. The study composed of four steps: for the PLR group, step 1 - inflation of the tourniquet while the patient was supine; step 2 - the patient's legs were raised to a 45° angle; step 3 - the tourniquet was deflated while the patient's legs were still raised; and step 4 - the legs were returned to the supine position. In the control group, the same perioperative procedure was used, but PLR was not conducted. MAIN OUTCOME MEASURES: The patients' blood pressure and heart rate were measured before, during and after tourniquet deflation. RESULTS: After tourniquet deflation, the magnitude of the changes in blood pressure and heart rate was less in the PLR group than that in the control group. In addition, the blood pressure nadir also occurred later in the PLR group than in the controls. CONCLUSION: Bilateral PLR is a simple, reversible manoeuvre that mimics rapid fluid loading. Bilateral PLR attenuates the severity of, and delays the time to, hypotension and tachycardia following deflation of a lower limb tourniquet. TRIAL REGISTRATION: ClinicalTrials.gov number NCT01592669.