Normal Saline Infusion Research Articles

Dexmedetomidine versus haloperidol for prevention of delirium during non-invasive mechanical ventilation

BackgroundDelirium is a common problem among intensive care patients and can contribute to non-invasive ventilation (NIV) failure. Prevention of delirium may improve the outcome and success rate of NIV. The aim of the current study was to compare the effects of using dexmedetomidine and haloperidol for prevention of delirium during NIV.Patients and methodsNinety adult intensive care patients of ASA physical status III and IV on NIV were randomly allocated to three equal groups. Group D (30 patients) received dexmedetomidine continuous intravenous infusion of 0.2–0.7 μg/kg/h preceded by a loading dose of 1.0 μg/kg intravenously over 10 min if needed, group H (30 patients) received haloperidol continuous intravenous infusion of 0.5–2 mg/h preceded by a loading dose of 2.5 mg intravenously if needed and group P (30 patients) received normal saline infusion. Supplementary sedation or analgesia was given when needed. Our primary outcome measure was the incidence of delirium. Duration of non-invasive mechanical ventilation, incidence of endotracheal intubation during NIV, length of ICU stay, and length of hospital stay, adverse events and mortality were recorded. Delirium was diagnosed using the Confusion Assessment Method for the ICU (CAM-ICU). Hemodynamic parameters and respiratory rate were recorded.ResultsThe incidence of delirium was significantly lower in dexmedetomidine group 3/30 (10%) than haloperidol 10/30 (33.3%) and placebo groups 13/30 (43.3%) groups. Duration of NIV was significantly shorter in dexmedetomidine group than in placebo group and shorter than haloperidol group. The incidence of endotracheal intubation was significantly less in dexmedetomidine group compared to placebo and haloperidol groups. The length of ICU and hospital stay was significantly shorter in dexmedetomidine group compared to haloperidol and placebo groups Bradycardia occurred significantly more in dexmedetomidine group while prolonged corrected QT (QTc) interval occurred only in haloperidol group (2 patients). A significantly lower incidence of respiratory tract infections was noted in dexmedetomidine group. The need for supplementary sedatives and analgesic was significantly less in dexmedetomidine group compared to haloperidol and placebo groups.ConclusionDexmedetomidine is more effective than haloperidol for prevention of delirium during NIV with lower incidence of endotracheal intubation and shorter ICU and hospital stay. Bradycardia is more frequent with dexmedetomidine use.

Abstract PR135

Background & Objectives: The administration of crystalloid fluid therapy for resuscitation, to restore euvolaemia, and/or improve cardiac output (CO) is perhaps the most frequent therapeutic intervention in medicine. Several studies based on mathematical modelling of volume kinetics have suggested that the effect of a fixed volume of intravenous fluid varies considerably with baseline hydration state, rate of fluid infusion and the presence or absence of anaesthesia.[i],[ii],[iii] It has been demonstrated that the degree of plasma expansion produced by the same volume of IV crystalloid is greater with a lower rate of infusion, and more prolonged with longer duration of infusion.[ii] This pilot study aims to characterize the effect of 1L of IV normal saline (NS) administered in a bolus versus continuous infusion on CO, heart rate (HR), and systemic blood pressures in 7 healthy volunteers. We hypothesize that an infusion of 1L of NS given over 120 minutes will produce a more sustained increase in CO when compared to a rapid bolus given over 30 minutes. Materials & Methods: Seven healthy male volunteers between aged 18–65 years participated in 2 experiments each on separate days where 1L NS was given either over 30min or 120min. Haemodynamic data was gathered using a non-invasive finger arterial pressure monitor. Results: When compared to baseline, rapid infusion of 1L of saline over 30 min produced a fall in CO by 0.62L/min (p<0.0001), whereas there was a marginal but significant increase in CO during infusion of 1L NS over 120min of 0.02L/min (p<0.0001). The difference in CO between the groups was also significant with a higher CO seen in the infusion group (p<0.0001) (Figure 1). This effect was mirrored by changes in systolic blood pressure (SBP) measurements for each group (p<0.0001).Conclusion: Continuous infusion of 1L NS in healthy male volunteers produced a greater increase in both SBP and CO than rapid infusion, which produced a paradoxical fall in both of these haemodynamic parameters.

Noradrenaline and dobutamine effects on the volume expansion with normal saline in rabbits subjected to hemorrhage.

To evaluate the effects of dobutamine (DB), noradrenaline (NA), and their combination (NADB), on volume retention in rabbits submitted to hemorrhage. Thirty six rabbits were randomly divided into 6 groups: SHAM, Control, Saline, DB, NA, DB+NA. All the animals, except for SHAM, were subjected to hemorrhage of 25% of the calculated blood volume. Control animals were replaced with their own blood. The other groups received NSS 3 times the volume withdrawn. The intravascular retention, hematocrit, diuresis, central venous pressure, mean arterial pressure, NGAL, dry-to-wet lung weight ratio (DTWR) and the lung and kidney histology were analyzed. Replacement with NSS and NA, DB or NA+DB did not produce differences in the intravascular retention. After hemorrhage, the animals presented a significant decrease in the MAP and CVP, which were maintained until volume replacement. Regarding NGAL, dry-to-wet-lung-weight ratio, lung and kidney histology, there were no statistical differences between the groups. The use of noradrenaline, dobutamine or their combination did not increase the intravascular retention of volume after normal saline infusion.

Abstract PR347

Background & Objectives: Postoperative pain management is challenging. There is still room for improvement despite established acute pain protocols. We compared the efficacy between two low doses of intraoperative ketamine infusions in reducing the first 24 hours postoperative morphine consumption. Materials & Methods: Fifty patients with American Society of Anesthesiologists’ (ASA) Physical Status I or II aged between 18 to 65 years undergoing open gynaecological surgeries were randomised into three groups to receive intraoperative infusions of normal saline (Group A), ketamine at 0.25 mg/kg/hour (Group B) or ketamine at 0.5 mg/kg/hour (Group C). All patients received intraoperative intravenous morphine 0.1 mg/kg. Postoperative morphine consumption via patient controlled analgesia device, visual analogue scale (VAS) for pain and ketamine side effects were recorded at times zero, 10, 20, 30 minutes, and 6, 12, 24 hours postoperatively. Results: Mean cumulative 24 hours postoperative morphine consumption was significantly reduced in Groups B and C (23.1 ± 8.4 mg and 16.7 ± 7.2 mg respectively) when compared to Group A (30.9 ± 11.1 mg). Group C had significantly lower VAS pain scores and rescue morphine requirements in the postoperative period. There were no significant adverse side effects in all 3 groups. Conclusion: Intraoperative ketamine infusion at 0.5 mg/kg/hour significantly improved pain control and reduced postoperative morphine consumption.

Inflammatory Profile in Response to Uncontrolled Hemorrhage in a Non-Human Primate (Rhesus Macaque) Model.

Uncontrolled hemorrhage (UH), the leading cause of potentially survivable combat-related death, elicits a deleterious inflammatory response. Our group previously reported an increased secretion of pro-inflammatory cytokines in a novel non-human primate model of UH; however, to better understand the molecular profile of the inflammatory response to UH, we performed a comprehensive evaluation of inflammation at the proteomic and transcriptomic level. Anesthetized rhesus macaques (n = 8) underwent UH by 60% left lobe hepatectomy T = 0 min. At T = 5 min, animals received 11 mL of 5% albumin followed by normal saline infusion to a total resuscitation volume of 20 mL/kg by T = 120 min. Blood (T = 0, 5, 20, 120, 480 min) was collected for qPCR and multiplex cytokine quantification. Results from each non-human primate (NHP) per time-point are shown. Statistical analysis by one-way ANOVA with repeated measures, P <0.05 was considered significant. Luminex analysis in serum revealed significant up-regulation compared with baseline of 8 cytokines/chemokines starting T = 120 min postinjury and significant down-regulation of 4 cytokines/chemokines as early as T = 20 min postinjury. Gene expression analysis in white blood cells uncovered 10 genes that were up-regulated greater than 3-fold compared with baseline and 29 genes that were down-regulated greater than 3-fold. The present study confirms the presence of systemic inflammation after UH at the proteomic and transcriptomic level providing insight into the inflammatory mediators that are involved as well as their kinetics following UH. The data demonstrates that NHP hemorrhage models may be suitable for evaluating therapeutics to control inflammation following hemorrhage.

The effect of dexmedetomidine pretreatment on the median effective bolus dose of propofol for facilitating laryngeal mask airway insertion.

We designed this study to investigate the effect of dexmedetomidine (1μg/kg) pretreatment on the median effective dose (ED50) of propofol for facilitating successful laryngeal mask airway (LMA) insertion compared to propofol alone. Forty patients were randomized to either the control group (n=21) or the dexmedetomidine group (n=19). After infusion of normal saline or dexmedetomidine 1µg/kg over 10min, 1% lidocaine 0.5mg/kg, followed by propofol 2.5mg/kg was administered and the laryngeal mask airway was inserted without muscle relaxants. The ED50 of propofol for successful LMA insertion was determined by the modified Dixon's up-and-down method. The ED50 and ED95 were also calculated using an isotonic regression method, based on the pooled adjacent-violators algorithm-adjusted response rate, and the confidential interval (CI) was estimated using a bootstrap approach. The ED50 of propofol for smooth insertion of the LMA was significantly higher in the control group than in the dexmedetomidine group (3.1±0.4 vs 1.9±0.3mg/kg, P<0.001). From isotonic regression analysis using a bootstrap approach, the ED50 and ED95 of propofol was 2.9mg/kg (83% CI 2.5-3.3mg/kg) and 3.9mg/kg (95% CI 3.5-4.0mg/kg) in the control group, and 1.8mg/kg (83% CI 1.8-2.1mg/kg) and 2.4mg/kg (95% CI 2.0-2.5mg/kg) in the dexmedetomidine groups, respectively. The apnea time was not significantly different between the two groups. Pretreatment with dexmedetomidine 1μg/kg could reduce the propofol requirement by 38% for facilitating LMA insertion without prolonged respiratory depression and hemodynamic instability.

Tibial nerve stimulation to inhibit the micturition reflex by an implantable wireless driver microstimulator in cats.

Background:Traditional tibial nerve stimulation (TNS) has been used to treat overactive bladder syndrome (OAB), but there are some shortcomings. Thus, a novel alternative is needed for the treatment of OAB. The study investigated the effects of a new type of tibial nerve microstimulator on the micturition reflex in cats.Methods:An implantable wireless driver microstimulator was implanted around the tibial nerve in 9 α-chloralose anesthetized cats. Cystometry was performed by infusing 0.9% normal saline (NS) or 0.25% acetic acid (AA) through a urethral catheter. Multiple cystometrograms were performed before, during, and after TNS to determine the inhibitory effect of the microstimulator on the micturition reflex.Results:TNS at 2 threshold (T) intensity significantly increased the bladder capacity (BC) during NS infusion. Bladder overactivity was irritated by the intravesical infusion of 0.25% AA, which significantly reduced the BC compared with the NS infusion. TNS at 2 T intensity suppressed AA-induced bladder overactivity and significantly increased the BC compared with the AA control.Conclusion:The implantable wireless driver tibial nerve microstimulator appears to be effective in inhibiting the micturition reflex during physiologic and pathologic conditions. The implantable wireless driver tibial nerve microstimulator could be used to treat OAB.

Traumatic Brain Injury: Bolus Versus Continuous Infusion of 3% Hypertonic Saline

Hypertonic saline (HTS) is used as an adjunct in the conservative management of increased intracranial pressure; however, the ideal concentration or route of delivery is unknown. Our objective was to assess whether there is a difference in route of delivery, bolus versus infusion, of 2% versus 3% HTS in patients with traumatic brain injury. The study comprises a retrospective analysis of all patients who sustained traumatic brain injury resulting in increased intracranial pressure that required HTS from January 2012 to December 2014. We examined time to therapeutic serum sodium concentration greater or equal to 150 mEq; incidence of ventriculostomy placement and neurosurgical intervention for refractory intracanial hypertension; and disability burden among the different infusates and route of delivery. A total of 169 patients received either 2% or 3% HTS, given as a bolus or continuous infusion. Patients had an average age of 61.4 years; 100 patients (59.2%) were male and 69 (40.8%) were female; 62 patients were taking either an antiplatelet or anticoagulant agent. Infusion of 3% saline was associated with the shortest interval to reaching a therapeutic level at 1.61 days (P = 0.024). There was no statistically significant difference between placement of a ventriculostomy among the bolus and infusion groups of 3% normal saline (NS) (P = 0.475). However, neurosurgical intervention was less prevalent in those receiving 3% infusion (P = 0.013). Infusion of 3% HTS was associated with a more rapid increase in serum sodium to therapeutic levels. Neurosurgical intervention for refractory hypertension was less prevalent in the 3% NS infusion group.

Sanguinate's effect on pial arterioles in healthy rats and cerebral oxygen tension after controlled cortical impact

Sanguinate, a polyethylene glycol-conjugated carboxyhemoglobin, was investigated for cerebral vasoactivity in healthy male Sprague-Dawley rats (Study 1) and for its ability to increase brain tissue oxygen pressure (PbtO2) after controlled cortical impact (CCI) — traumatic brain injury (TBI) (Study 2). In both studies ketamine-acepromazine anesthetized rats were ventilated with 40% O2. In Study 1, a cranial window was used to measure the diameters of medium — (50–100μm) and small-sized (<50μm) pial arterioles before and after four serial infusions of Sanguinate (8mL/kg/h, cumulative 16mL/kg IV), volume-matched Hextend, or normal saline. In Study 2, PbtO2 was measured using a phosphorescence quenching method before TBI, 15min after TBI (T15) and then every 10min thereafter for 155min. At T15, rats received either 8mL/kg IV Sanguinate (40mL/kg/h) or no treatment (saline, 4mL/kg/h). Results showed: 1) in healthy rats, percentage changes in pial arteriole diameter were the same among the groups, 2) in TBI rats, PbtO2 decreased from 36.5±3.9mmHg to 19.8±3.0mmHg at T15 in both groups after TBI and did not recover in either group for the rest of the study, and 3) MAP increased 16±4mmHg and 36±5mmHg after Sanguinate in healthy and TBI rats, respectively, while MAP was unchanged in control groups. In conclusion, Sanguinate did not cause vasoconstriction in the cerebral pial arterioles of healthy rats but it also did not acutely increase PbtO2 when administered after TBI. Sanguinate was associated with an increase in MAP in both studies.

Mesenchymal stem cells improve the outcomes of liver recipients via regulating CD4+ T helper cytokines in rats

Bone marrow mesenchymal stem cells (BMMSCs) exert immunosuppressive activities in transplantation. This study aimed to determine whether BMMSCs reduce acute rejection and improve outcomes of liver transplantation in rats. Orthotopic liver transplantation from Lewis to Brown Norway rats was performed, which was followed by the infusion of BMMSCs through the penile superficial dorsal vein. Normal saline infusion was used as a control. Animals were sacrificed at 0, 24, 72, or 168 hours after BMMSCs infusion. Liver grafts, and recipient serum and spleen tissues were obtained. Histopathology, apoptosis, serum liver enzymes, serum cytokines, and circulating regulatory T (Treg), Th1, Th2 and Th17 cells were assessed at each time point. BMMSCs significantly attenuated acute rejection and improved the survival rate of allogeneic liver transplantation recipients. Liver enzymes and liver apoptosis were significantly alleviated. The levels of the Th1/Th2 ratio-associated cytokines such as IL-2 and IFN-gamma were significantly reduced and IL-10 was significantly increased. The levels of the Th17/Tregs axis-associated cytokines such as IL-6, IL-17, IL-23, and TNF-alpha were significantly reduced, whereas TGF-beta concentration was significantly increased. Moreover, flow cytometry analysis showed that the infusion of BMMSCs significantly increased Th2 and Treg cells and decreased Th1 and Th17 cells. BMMSCs had immunomodulatory effects, attenuated acute rejection and improved outcomes of allogeneic liver transplantation in rats by regulating the levels of cytokines associated with Th1/Th2 and Th17/Treg ratios.

Opportunities for Emergency Medical Services (EMS) Care of Syncope.

Introduction Emergency Medical Service (EMS) systems are vital in the identification, assessment, and treatment of trauma, stroke, myocardial infarction, and sepsis patients, improving early recognition, resuscitation, and transport. Emergency Medical Service personnel provide similar care for patients with syncope. The role of EMS in the management of patients with syncope has not been reported. Hypothesis/Objective The objective of this study was to describe the management of out-of-hospital syncope by prehospital providers in an urban EMS system. This was a retrospective cohort study of consecutively enrolled patients over 18 years of age, over a two-year period, who presented by EMS with syncope, or near-syncope, to a tertiary care emergency department (ED). Demographics included comorbidities, history, and physical exam findings documented by prehospital providers, as well as the interventions provided. Data were collected from standardized patient care records for descriptive analysis. Of the 723 patients presenting with syncope to the ED, 284 (39.3%) were transported by EMS. Compared to non-EMS patients, those who arrived by ambulance were older (mean age 65 [SD = 18.5] years versus 61 [SD = 19.2] years; P = .019). There were no statistically significant differences in cardiovascular comorbidities (hypertension, coronary artery disease, diabetes mellitus, stroke, or congestive heart failure) between EMS and non-EMS patients. The most common chief complaints were fainting (50.0%) and dizziness (44.7%). The most common intervention provided was cardiac monitoring (55.6%), followed by administration of normal saline infusion (50.5%), oxygen (41.9%), blood glucose check (41.5%), and electrocardiogram (EKG; 40.5%). Emergency Medical Service personnel transport more than one-third of patients presenting to the ED with syncope. Documentation of key elements of the history (witnesses, prodrome, predisposing factors, and post-event symptoms) and physical examination were not recorded consistently. Long BJ , Serrano LA , Cabanas JG , Bellolio MF . Opportunities for Emergency Medical Services (EMS) care of syncope. Prehosp Disaster Med. 2016;31(4):349-352.

Changes in expression of spinal divalent metal transporter 1 during remifentanil-induced hyperalgesia in a rat model of incisional pain

Objective To evaluate the changes in the expression of spinal divalent metal transporter 1 (DMT1) during remifentanil-induced hyperalgesia in a rat model of incisional pain. Methods Thirty-two male Sprague-Dawley rats, weighing 240-260 g, aged 2-3 months, were randomly divided into 4 groups (n=8 each) using a random number table: control group (group C), incisional pain group (group I), remifentanil group (group R), and incisional pain+ remifentanil group (group I+ R). In group C, normal saline was infused for 60 min at a rate of 0.1 ml·kg-1·min-1.A 1-cm longitudinal incision was made through skin, fascia and muscle of the plantar aspect of the left hindpaw in sevoflurane-anesthetized rats, and normal saline was infused intravenously for 60 min at a rate of 1.0 μg·kg-1·min-1 at the same time in group I. In group R, remifentanil was infused for 60 min at a rate of 1.0 μg·kg-1·min-1.In group I+ R, the model of incisional pain was established, and remifentanil was simultaneously infused for 60 min at a rate of 1.0 μg·kg-1·min-1.At 24 h before normal saline or remifentanil infusion and 6, 24 and 48 h after the end of infusion (T0-3), the mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured.All the rats were sacrificed after the last measurement of pain thresholds, and the spinal cord was removed for determination of DMT1 with/without iron-responsive element [DMT1(+ )IRE and DMT1(-)IRE] expression (by Western blot analysis and immunohistochemistry). Results Compared with group C, the MWT was significantly decreased, and the TWL was significantly shortened at T1-3, and the expression of spinal DMT1(-)IRE was significantly up-regulated in I, R and I+ R groups (P 0.05). Conclusion Spinal DMT1(-)IRE activation may be involved in the mechanism underlying remifentanil-induced hyperalgesia in a rat model of incisional pain. Key words: Piperidines; Pain, postoperative; Hyperalgesia; Cation transport proteins; Spinal cord

Intralipid™ administration attenuates the hypotensive effects of acute intravenous amiodarone overdose in a swine model

PurposeTo investigate whether a lipid emulsion could counteract the hypotensive effects of amiodarone overdose after an acute intravenous administration and improve 4 h survival in an established model of swine cardiovascular research. MethodsTwenty pigs were intubated and instrumented to measure aortic pressures and central venous pressures (CVP). After allowing the animals to stabilize for 60 minutes, amiodarone overdose (1 mg/kg/min) was initiated for a maximum of 20 minutes. Afterwards, the animals were randomized into 2 groups. Group A (n = 10) received 0.9% Normal Saline (NS) and Group B (n = 10) received 20% Intralipid® (ILE). A bolus dose of 2 ml/kg in over 2 min time was initially administered in both groups followed by a 45 min infusion (0.2 ml/kg/min) of either NS or ILE. ResultsAll animals survived the overdose and all animals survived the monitoring period of 4 hours. Systolic aortic pressure (SpthAorta) (6.90 vs 14.10 mmHg, P = .006) and mean arterial pressure (MAP) (6.10 vs 14.90 mmHg, P = .001) were higher in the ILE group 2 min after the bolus ILE infusion. This difference was maintained for 15 min after ILE infusion for both SpthAorta (7.85 vs 13.15 mmHg, P = .044) and MAP (7.85 vs 13.15 mmHg, P = .042). Animals that received ILE had higher CVP (11.6 vs 15.7 mmHg, P = .046), an effect which was attenuated 2 and 4 hours post administration. Animals receiving ILE were more acidotic (7.21 vs 7.38, P = .048) in the monitoring period compared to animals receiving NS. ConclusionsIntralipid attenuated the hypotensive effects of amiodarone toxicity for a period of 15 minutes compared to animals receiving NS.

Identification of Renal Pelvic Sodium Channel Input to the Brain Stem and Hypothalamus in the Rat

There is considerable evidence that elevated central sympathetic nerve activity contributes to the development of essential hypertension. It has been suggested that renal afferent nerves facilitate the increase in central sympathetic drive. Renal afferent projections to the CNS have been mapped using tract tracing techniques (e.g., pseudorabies virus) and electrical stimulation (c‐fos activation) demonstrating a number of regions that receive renal sensory input but not discriminating between chemo and mechanoreceptor afferents. Since renal sensory neurons are highly concentrated in the renal pelvis, we sought to identify the central projections of renal pelvic afferent nerves sensitive to hypertonic saline. We hypothesized that hypertonic saline would activate renal pelvic epithelial sodium channel (ENaC) projections to key autonomic areas of the CNS involved in blood pressure control.We implanted a triple lumen cannula into the left renal pelvis of rats and catheterized the femoral artery to measure arterial pressure and heart rate. After recovery, the left kidney continued to function voiding urine. Five days later, the renal pelvis was flushed in a push‐pull manner (40–60 μl/min) while recording renal pelvic pressure (third pelvic cannula) to avoid mechanoreceptor activation. We used either normotonic saline (308 mOsm/L), hypertonic saline (500 mOsm/L) or a mixture of hypertonic saline and amiloride (10 μM). We compared these results to instrumented sham rats without any infusion. After 2 hours, rats were deeply anesthetized and perfused transcardially with saline then 4% paraformaldehyde. Brains were removed and sectioned (50 μm) and stained immunohistochemically for c‐fos, a marker of increased neuronal activity. We observed labeled neurons within several regions of the CNS using ImageJ software. A number of regions known to regulate visceral input and/or sympathetic outflow in the brain were activated including the parabrachial nucleus (PBN), paraventricular hypothalamus (PVH), and nucleus tractus solitarius (NTS). The most consistent activation was observed in the PBN el‐inner (151 cells/mm2), parvocellular PVH (113 cells/mm2), and NTS (89.3 cells/mm2) compared to normal saline infusion (80.5, 58.4, and 61.4 cells/mm2 respectively) and sham treatment (34.8, 62.1, and 29.9 cells/mm2 respectively). The activation with hypertonic saline was attenuated by amiloride (16.1, 93.2, and 35.0 cells/mm2 respectively). Therefore, the results suggest that hypertonic saline activates c‐fos in the PBN el‐inner, parvocellular PVH, and NTS, in addition to other areas. Since the activation could be antagonized with an ENaC antagonist in the renal pelvis, we propose that the afferents have ENaC. We have identified specific renal afferent projections and developed a technique for determining selective projections from the renal pelvis. It remains to be determined whether these ENaC and specific renal sensory nerves are responsible for facilitating the development of hypertension.Support or Funding InformationSupported by St. Louis University and Washington University

Thrombolytics in VAD management — A single-center experience

BackgroundWith continued increase in the use of mechanical circulatory support, the incidence of device thrombus remains a challenge. This study is a retrospective analysis of data at a single center to assess the safety and efficacy of thrombolytic use in durable mechanical assist devices. MethodsData was analyzed retrospectively from 154 patients who underwent left ventricular assist device (LVAD) implantation from 1/1/2005 to 6/30/2014. The HMII device was implanted in 131 patients while 23 received the HVAD. LVAD thrombus was diagnosed when lactate dehydrogenase levels exceeded 1000units/l accompanied by clinical signs of hemolysis and heart failure, echocardiographic data and surges in pump power. TPA (tissue plasminogen activator) protocol consisted of a 5mg intravenous bolus followed by 3mg/h infusion in normal saline for 10h. If symptoms persisted another cycle of TPA at 1mg/h was continued up to 48h. ResultsThe TPA group had a 70% success rate. Success was defined as complete resolution of hemolysis and clinical symptoms with no requirement for LVAD exchange at 30days. 95% survival was noted at 30days and 90% were free of a hemorrhagic stroke in the TPA group. The rates of hemorrhagic strokes in the TPA group and the control group were not different (OR=0.92). ConclusionThe TPA protocol described here was successful consistently. Though this study is limited by its size and retrospective nature it leads the way for larger studies to generate more robust comparisons between different types of mechanical assist devices as well as the tailored use of thrombolytics in this patient population.

Experimental study on the protective effect of propofol on liver injury in rats with sepsis

Objective: To observe the protective effect of propofol on liver injury in rats with sepsis and explore its protective mechanism. Methods: 24 Wister rats were randomly divided into 3 groups, with 8 rats in each group: the sham operation group, the saline group and the propofol group. An intraperitoneal injection of LPS 8 mg/kg was used in the saline group, with continuous infusion of normal saline. An intraperitoneal injection of LPS 8 mg/kg and continuous infusion of propofol saline solution were also performed in the propofol group. Results: Compared with the saline group, the levels of ALT, AST, IL-6 and TNF-α in the sham operation group and the propofol group were significantly lower than those in the saline group. Conclusions: Propofol has a certain protective effect on liver injury in rats with sepsis.

Diagnosis and treatment of hyponatraemia in neurosurgical patients

Hyponatraemia is the most common electrolyte imbalance in neurosurgical patients. Acute hyponatraemia is particularly common in neurosurgical patients after any type of brain insult, including brain tumours and their treatment, pituitary surgery, subarachnoid haemorrhage or traumatic brain injury. Acute hyponatraemia is an emergency condition, as it leads to cerebral oedema due to passive osmotic movement of water from the hypotonic plasma to the relatively hypertonic brain which ultimately is the cause of the symptoms associated with hyponatraemia. These include decreased level of consciousness, seizures, non-cardiogenic pulmonary oedema or transtentorial brain herniation. Prompt treatment is mandatory to prevent such complications, minimize permanent brain damage and therefore permit rapid recovery after brain insult. The infusion of 3% hypertonic saline is the treatment of choice with different rates of administration based on the severity of symptoms and the rate of drop in plasma sodium concentration.The pathophysiology of hyponatraemia in neurotrauma is multifactorial; although the syndrome of inappropriate antidiuresis (SIADH) and central adrenal insufficiency are the commonest causes encountered. Fluid restriction has historically been the classical treatment for SIADH, although it is relatively contraindicated in some neurosurgical patients such as those with subarachnoid haemorrhage. Furthermore, many cases admitted have acute onset hyponatraemia, who require hypertonic saline infusion. The recently developed vasopressin receptor 2 antagonist class of drug is a promising and effective tool but more evidence is needed in neurosurgical patients. Central adrenal insufficiency may also cause acute hyponatraemia in neurosurgical patients; this responds clinically and biochemically to hydrocortisone. The rare cerebral salt wasting syndrome is treated with large volume normal saline infusion. In this review, we summarize the current evidence based on the clinical presentation, causes and treatment of different types of hyponatraemia in neurosurgical patients.

Randomized, Double-Blinded Trial of Magnesium Sulfate Tocolysis versus Intravenous Normal Saline for Preterm Nonsevere Placental Abruption.

Objective To evaluate the efficacy and safety of magnesium sulfate in the resolution of vaginal bleeding and contractions in nonsevere placental abruption. Study Design Thirty women between 24 and 34 weeks of gestation diagnosed with nonsevere placental abruption were randomized to receive magnesium sulfate tocolysis or normal saline infusion. The primary outcome was the proportion of women undelivered at 48 hours with resolution of vaginal bleeding and uterine contractions. Maternal and neonatal outcomes were also compared. Results Fifteen (50%) women received magnesium sulfate tocolysis and 15 (50%) received intravenous saline. There was no difference in the number of women who were undelivered at 48 hours with resolution of vaginal bleeding and contractions in the magnesium sulfate (80.0%) and saline (66.7%; p-value = 0.68) groups. There were no differences between groups in the gestational age at randomization, time to uterine quiescence, time on study drug, length of hospitalization, days from randomization to delivery, incidence of side effects, or admissions to the neonatal intensive care unit. Conclusions Magnesium sulfate tocolysis did not provide a significant difference in pregnancy prolongation in the management of preterm nonsevere placental abruption. Recruitment goals were not met due to the introduction of the use of magnesium sulfate for neuroprotection.

Abstract WP339: Cerebral Blood Flow Response to Bolus Normal Saline

Introduction: Intravenous infusion of 0.9% normal saline (NS) is used routinely after acute ischemic stroke (AIS). Since cerebral autoregulation is impaired after AIS, volume expansion due to NS infusion holds potential to increase cerebral blood flow (CBF). Here, we use transcranial optics to quantify the CBF response to a NS bolus. Hypothesis: An increase in CBF during a 500cc bolus of NS will be detectable using transcranial optics. Methods: Adults ≥ 18 years with unilateral supratentorial AIS were enrolled within 96 hours of onset. Relative CBF was noninvasively monitored bifrontally using diffuse correlation spectroscopy with a 15 minute baseline, followed by a 500cc bolus of NS administered over 30 minutes, and a 15 minute post-bolus period. Repeated measures ANOVA and piecewise linear regression were used to quantify the effects of NS bolus on CBF. Results: Data from 36 subjects was analyzed (mean age: 64.7±13.5; median NIHSS: 4.5 (IQR 2-9)) at a mean of 66 ± 18 hours after symptom onset. Mean arterial pressure increased during the NS bolus (mean 3.4±9.0 mm Hg). Mean CBF during NS was 22±17% higher than baseline in the ipsilateral hemisphere (p&lt;0.001), and 21±17% higher in the contralateral hemisphere, (p&lt;0.001). Piecewise linear regression estimated an average rate of CBF increase during NS of 0.71%/min in the ipsi and 0.68%/min in the contralateral hemispheres. An average rate of CBF increase of 0.44%/min and 0.48%/min was also observed during the baseline period in the ipsi/contralateral hemispheres. Conclusion: NS infusion was associated with a significant increase in CBF from baseline in both hemispheres in patients with subacute stroke. CBF responses to NS infusion were heterogeneous across subjects, suggesting the potential of bedside CBF monitoring for personalized CBF management in patients with AIS.

A comparison of the postoperative analgesic effects of intravenous dexmedetomidine with a combination of dexmedetomidine and bupivacaine wound infiltration for lower segment cesarean section: A prospective, randomized study

Background and aim This study was designed to compare the postoperative analgesic effect of dexmedetomidine administered intravenously or in wound infiltration with bupivacaine in patients undergoing cesarean section. Patients and methods Ninety female patients scheduled for cesarean section were randomly allocated into three equal groups: group I received 100 ml normal saline infusion over 10 min before closure plus wound infiltration with 25 ml of 0.25% bupivacaine at the end of surgery; group II received 1 mg/kg of dexmedetomidine in 100 ml normal saline infusion over 10 min before closure plus wound infiltration with 25 ml of 0.25% bupivacaine at the end of surgery; and group III received 100 ml normal saline infusion over 10 min before closure plus wound infiltration with 1 mg/kg of dexmedetomidine added to 25 ml of 0.25% bupivacaine at the end of surgery. The number of patients requiring rescue analgesia, total morphine consumption during the first 24 h after the operation, and the level of sedation were recorded. Results Morphine consumption was significantly less in patients receiving dexmedetomidine by either route. All patients in group I required supplemental morphine, whereas 14 patients in group II and 16 patients in the wound infiltration group required supplemental morphine. Patients in group II had more hypotension and sedation compared with other groups. Conclusion Dexmedetomidine provided effective postoperative analgesia and reduced morphine consumption when administered intravenously or in wound infiltration with bupivacaine. The incidence of complications was less with wound infiltration.