Predicting fluid responsiveness in spontaneously breathing parturients undergoing caesarean section via carotid artery blood flow and velocity time integral measured by carotid ultrasound: a prospective cohort study.

BACKGROUND: Present evidence suggests that the Doppler ultrasonographic indices, such as carotid artery blood flow (CABF) and velocity time integral (VTI), had the ability to predict fluid responsiveness in non-obstetric patients. The purpose of this study was to assess their capacity to predict fluid responsiveness in spontaneous breathing parturients undergoing caesarean section and to determine the effect of detecting and management of hypovolemia (fluid responsiveness) on the incidence of hypotension after anaesthesia. METHODS: A total of 72 full term singleton parturients undergoing elective caesarean section were enrolled in this study. CABF, VTI, and hemodynamic parameters were recorded before and after fluid challenge and assessed by carotid artery ultrasonography. Fluid responsiveness was defined as an increase in stroke volume index (SVI) of 15% or more after the fluid challenge. RESULTS: Thirty-one (43%) patients were fluid responders. The area under the ROC curve to predict fluid responsiveness for CABF and VTI were 0.803 (95% CI, 0.701-0.905) and 0.821 (95% CI, 0.720-0.922). The optimal cut-off values of CABF and VTI for fluid responsiveness was 175.9 ml/min (sensitivity of 74.0%; specificity of 78.0%) and 8.7 cm/s (sensitivity of 67.0%; specificity of 90.0%). The grey zone for CABF and VTI were 114.2-175.9 ml/min and 6.8-8.7 cm/s. The incidence of hypotension after the combined spinal-epidural anaesthesia (CSEA) was significantly higher in the Responders group 25.8% (8/31) than in the Non-Responders group 17.1(7/41) (P < 0.001). The total incidence of hypotension after CSEA of the two groups was 20.8% (15/72). CONCLUSIONS: Ultrasound evaluation of CABF and VTI seem to be the feasible parameters to predict fluid responsiveness in parturients undergoing elective caesarean section and detecting and management of hypovolemia (fluid responsiveness) could significantly decrease incidence of hypotension after anaesthesia. TRIAL REGISTRATION: The trial was registered at the Chinese Clinical Trial Registry (ChiCTR) ( www.chictr.org ), registration number was ChiCTR1900022327 (The website link: https://www.chictr.org.cn/showproj.html?proj=37271 ) and the date of trial registration was in April 5, 2019. This study was performed in accordance with the Declaration of Helsinki and approved by the Research Ethics Committee of Women's Hospital, Zhejiang University School of Medicine (20,180,120).

Phlebotomy resulting in controlled hypovolemia to prevent blood loss in major hepatic resections (PRICE-2): study protocol for a phase 3 randomized controlled trial.

INTRODUCTION: Blood loss and red blood cell (RBC) transfusion in liver surgery are areas of concern for surgeons, anesthesiologists, and patients alike. While various methods are employed to reduce surgical blood loss, the evidence base surrounding each intervention is limited. Hypovolemic phlebotomy, the removal of whole blood from the patient without volume replacement during liver transection, has been strongly associated with decreased bleeding and RBC transfusion in observational studies. This trial aims to investigate whether hypovolemic phlebotomy is superior to usual care in reducing RBC transfusions in liver resection. METHODS: This study is a double-blind multicenter randomized controlled trial. Adult patients undergoing major hepatic resections for any indication will be randomly allocated in a 1:1 ratio to either hypovolemic phlebotomy and usual care or usual care alone. Exclusion criteria will be minor resections, preoperative hemoglobin <100g/L, renal insufficiency, and other contraindication to hypovolemic phlebotomy. The primary outcome will be the proportion of patients receiving at least one allogeneic RBC transfusion unit within 30 days of the onset of surgery. Secondary outcomes will include transfusion of other allogeneic blood products, blood loss, morbidity, mortality, and intraoperative physiologic parameters. The surgical team will be blinded to the intervention. Randomization will occur on the morning of surgery. The sample size will comprise 440 patients. Enrolment will occur at four Canadian academic liver surgery centers over a 4-year period. Ethics approval will be obtained at participating sites before enrolment. DISCUSSION: The results of this randomized control trial will provide high-quality evidence regarding the use of hypovolemic phlebotomy in major liver resection and its effects on RBC transfusion. If proven to be effective, this intervention could become standard of care in liver operations internationally and become incorporated within perioperative patient blood management programs. TRIAL REGISTRATION: ClinicalTrials.gov NCT03651154 . Registered on August 29 2018.

Reliability of Pre-Induction Inferior Vena Cava Assessment with Ultrasound for the Prediction of Post-Induction Hypotension in Neurosurgical Patients Undergoing Intracranial Surgery.

Background: Hypotension is one of the most common complications following induction of general anesthesia. Preemptive diagnosis and correcting the hypovolemic status can reduce the incidence of post-induction hypotension. However, an association between preoperative volume status and severity of post-induction hypotension has not been established in neurosurgical patients. We hypothesized that preoperative ultrasonographic assessment of intravascular volume status can be used to predict post-induction hypotension in neurosurgical patients. Our study objective was to establish the relationship between pre-induction maximum inferior vena cava (IVC) diameter, collapsibility index (CI), and post-induction reduction in mean arterial blood pressure in neurosurgical patients. Materials and Methods: A prospective observational study was conducted including 100 patients undergoing elective intracranial surgeries. IVC assessment was done before induction of general anesthesia. Receiver operating characteristic (ROC) curve analysis was used to determine the cutoff values of maximum and minimum IVC diameter (IVCDmax and IVCDmin, respectively) and CI for prediction of hypotension. Results: Post-induction hypotension was observed in 41% patients. Patients with small IVCDmax and higher CI% developed hypotension. The areas under the ROC curve (AUCs) were 0.64 (0.53-0.75) for IVCDmax and 0.69 (0.59-0.80) for IVCDmin. The optimal cutoff values were1.38 cm for IVCDmax and 0.94 cm for IVCDmin. The AUC for CI was 0.65 (0.54-0.77) and the optimal cutoff value was 37.5%. Conclusion: Pre-induction IVC assessment with ultrasound is a reliable method to predict post-induction hypotension resulting from hypovolemia in neurosurgical patients.

PragmaTic, prospEctive, randomized, controlled, double-blind, mulTi-centre, multinational study on the safety and efficacy of a 6% HydroxYethyl Starch (HES) solution versus an electrolyte solution in trauma patients: study protocol for the TETHYS study.

BACKGROUND: Trauma may be associated with significant to life-threatening blood loss, which in turn may increase the risk of complications and death, particularly in the absence of adequate treatment. Hydroxyethyl starch (HES) solutions are used for volume therapy to treat hypovolemia due to acute blood loss to maintain or re-establish hemodynamic stability with the ultimate goal to avoid organ hypoperfusion and cardiovascular collapse. The current study compares a 6% HES 130 solution (Volulyte 6%) versus an electrolyte solution (Ionolyte) for volume replacement therapy in adult patients with traumatic injuries, as requested by the European Medicines Agency to gain more insights into the safety and efficacy of HES in the setting of trauma care. METHODS: TETHYS is a pragmatic, prospective, randomized, controlled, double-blind, multicenter, multinational trial performed in two parallel groups. Eligible consenting adults ≥ 18 years, with an estimated blood loss of ≥ 500 ml, and in whom initial surgery is deemed necessary within 24 h after blunt or penetrating trauma, will be randomized to receive intravenous treatment at an individualized dose with either a 6% HES 130, or an electrolyte solution, for a maximum of 24 h or until reaching the maximum daily dose of 30 ml/kg body weight, whatever occurs first. Sample size is estimated as 175 patients per group, 350 patients total (α = 0.025 one-tailed, power 1-ß = 0.8). Composite primary endpoint evaluated in an exploratory manner will be 90-day mortality and 90-day renal failure, defined as AKIN stage ≥ 2, RIFLE injury/failure stage, or use of renal replacement therapy (RRT) during the first 3 months. Secondary efficacy and safety endpoints are fluid administration and balance, changes in vital signs and hemodynamic status, changes in laboratory parameters including renal function, coagulation, and inflammation biomarkers, incidence of adverse events during treatment period, hospital, and intensive care unit (ICU) length of stay, fitness for ICU or hospital discharge, and duration of mechanical ventilation and/or RRT. DISCUSSION: This pragmatic study will increase the evidence on safety and efficacy of 6% HES 130 for treatment of hypovolemia secondary to acute blood loss in trauma patients. TRIAL REGISTRATION: Registered in EudraCT, No.: 2016-002176-27 (21 April 2017) and ClinicalTrials.gov, ID: NCT03338218 (09 November 2017).

Comparison of non-invasive physiological assessment tools between simple and perforated appendicitis in children.

PURPOSE: The role of non-invasive measures of physiologic reserve, specifically the Compensatory reserve index (CRI) and the Shock index pediatric age-adjusted (SIPA), is unknown in the management of children with acute appendicitis. CRI is a first-in-class algorithm that uses pulse oximetry waveforms to continuously monitor central volume status loss. SIPA is a well-validated, but a discontinuous measure of shock that has been calibrated for children. METHODS: Children with suspected acute appendicitis (2-17 years old) were prospectively enrolled at a single center from 2014 to 2015 and monitored with a CipherOx CRI™ M1 pulse oximeter. CRI values range from 1 (normovolemia) to 0 (life-threatening hypovolemia). SIPA is calculated by dividing heart rate by systolic blood pressure and categorized as normal or abnormal, based on age-specific cutoffs. Univariate and multivariable regression models were developed with simple versus perforated appendicitis as the outcome. RESULTS: Almost half the patients (45/94, 48%) had perforated appendicitis. On univariate analysis, the median admission CRI value was significantly higher (0.60 versus 0.33, p < 0.001) and the ED SIPA values were significantly lower (0.90 versus 1.10, p = 0.002) in children with simple versus perforated appendicitis. In a multivariable model, only CRI significantly detected differences in the physiologic state between patients with simple and perforated appendicitis. CONCLUSIONS: CRI is a non-invasive measure of physiologic reserve that may be used to accurately guide early management of children with acute simple versus perforated appendicitis.

Vancomycin prophylaxis for revision hip arthroplasty in penicillin and cephalosporin sensitive patients: Is dose adjustment necessary in accordance with blood loss and fluid replacement?

OBJECTIVE: The aims of this study were (1) to investigate the changes in the serum concentration of prophylactically administrated vancomycin in the perioperative period of revision hip arthroplasty in penicillin/cephalosporin-allergic patients, (2) to assess whether the postoperative re-administration of vancomycin is needed, and (3) to determine the relationships of vancomycin serum concentration with blood loss, body weight, and fluid replacement in such patients. METHODS: This study consisted of 29 patients (20 females, 9 males; mean age=63.3 years; age range=45-79 years) with a history of penicillin/cephalosporin allergy undergoing revision hip arthroplasty secondary to aseptic loosening or periprosthetic fractures. Serum vancomycin levels were measured (1) before administration of vancomycin, (2) at the time of skin incision, (3) every 1,5 hours thereafter until the end of the operation, (4) during the skin closure, and (5) after three and 12 hours from the initial dosage. Data regarding body weight, amounts of intraoperative blood loss, fluid and blood replacements and postoperative wound drainage were recorded. RESULTS: The average blood loss, fluid replacement, and drain volume were 1280.3±575.8 (500-2700) mL, 2922.6±768.8 (1700-4600) mL, and 480.2±163.7 (200-850) mL, respectively. The mean levels of serum vancomycin were 46.3±21.8 (14.1-80.7) mg/L at the time of skin incision, 17.9±4.7 (9.4-30.9) and 9.8±2.2 (4.3-13.8) mg/L after 1.5 and 3 hours from the beginning of the surgery and 5.1±1.1 (2.9-6.8)mg/L after 12th hour postoperatively. The measured vancomycin levels were below the effective serum concentrations (< 5 mg/L) for 18 patients at 12 hours the administration of the first dose. A moderate level negative correlation between the blood loss/body weight ratio and vancomycin levels was found (p=0.004, r=-0.493). Predictive ROC curve analysis resulted in determining a blood loss volume higher than 1150 ml and a blood loss/body weight ratio higher than 18,5 is significant to estimate the vancomycin level below the minimum effective serum level at 12th hour postoperatively (AUC=0.793±0.16, p=0.009, AUC=0.753) 26±0.12, p=0.025, respectively). CONCLUSION: Evidence from this study has indicated vancomycin concentration at 12th hour is below the effective level in most patients. Thus, earlier repetitive infusion of vancomycin seems to be necessary in penicillin/cephalosporin-allergic patients undergoing revision hip arthroplasty, especially in those with high blood loss. LEVEL OF EVIDENCE: Level III, Therapeutic Study.

Predictors of hemodynamic decompensation in progressive hypovolemia: Compensatory reserve versus heart rate variability.

BACKGROUND: Hemorrhage remains the leading cause of death following traumatic injury in both civilian and military settings. Heart rate variability (HRV) and heart rate complexity (HRC) have been proposed as potential "new vital signs" for monitoring trauma patients; however, the added benefit of HRV or HRC for decision support remains unclear. Another new paradigm, the compensatory reserve measurement (CRM), represents the integration of all cardiopulmonary mechanisms responsible for compensation during relative blood loss and was developed to identify current physiologic status by estimating the progression toward hemodynamic decompensation. In the present study, we hypothesized that CRM would provide greater sensitivity and specificity to detect progressive reductions in central circulating blood volume and onset of decompensation as compared with measurements of HRV and HRC. METHODS: Continuous, noninvasive measurements of compensatory reserve and electrocardiogram signals were made on 101 healthy volunteers during lower-body negative pressure (LBNP) to the point of decompensation. Measures of HRV and HRC were taken from electrocardiogram signal data. RESULTS: Compensatory reserve measurement demonstrated a superior sensitivity and specificity (receiver operator characteristic area under the curve [ROC AUC] = 0.93) compared with all HRV measures (ROC AUC ≤ 0.84) and all HRC measures (ROC AUC ≤ 0.86). Sensitivity and specificity values at the ROC optimal thresholds were greater for CRM (sensitivity = 0.84; specificity = 0.84) than HRV (sensitivity, ≤0.78; specificity, ≤0.77), and HRC (sensitivity, ≤0.79; specificity, ≤0.77). With standardized values across all levels of LBNP, CRM had a steeper decline, less variability, and explained a greater proportion of the variation in the data than both HRV and HRC during progressive hypovolemia. CONCLUSION: These findings add to the growing body of literature describing the advantages of CRM for detecting reductions in central blood volume. Most importantly, these results provide further support for the potential use of CRM in the triage and monitoring of patients at highest risk for the onset of shock following blood loss.

Ultrasonographic inferior vena cava diameter response to trauma resuscitation after 1 hour predicts 24-hour fluid requirement.

BACKGROUND: Identification of occult hypovolemia in trauma patients is difficult. We hypothesized that in acute trauma patients, the response of ultrasound-measured minimum inferior vena cava diameter (IVCDMIN), IVC Collapsibility Index (IVCCI), minimum internal jugular diameter (IJVDMIN) or IJV Collapsibility Index (IJVCI) after up to 1 hour of fluid resuscitation would predict 24-hour resuscitation intravenous fluid requirements (24FR). METHODS: An NTI-funded, American Association for the Surgery of Trauma Multi-Institutional Trials Committee prospective, cohort trial was conducted at four Level I Trauma Centers. Major trauma patients were screened for an IVCD of 12 mm or less or IVCCI of 50% or less on initial focused assessment sonographic evaluations for trauma. A second IVCD was obtained 40 minutes to 60 minutes later, after standard-of-care fluid resuscitation. Patients whose second measured IVCD was less than 10 mm were deemed nonrepleted (NONREPLETED), those 10 mm or greater were repleted (REPLETED). Prehospital and initial resuscitation fluids and 24FR were recorded. Demographics, Injury Severity Score, arterial blood gasses, length of stay, interventions, and complications were recorded. Means were compared by ANOVA and categorical variables were compared via χ. Receiver operating characteristic curves analysis was used to compare the measures as 24FR predictors. RESULTS: There were 4,798 patients screened, 196 were identified with admission IVCD of 12 mm or IVCCI of 50% or less, 144 were enrolled. There were 86 REPLETED and 58 NONREPLETED. Demographics, initial hemodynamics, or laboratory measures were not significantly different. NONREPLETED had smaller IVCD (6.0 ± 3.7 mm vs. 14.2 ± 4.3 mm, p < 0.001) and higher IVCCI (41.7% ± 30.0% vs. 13.2% ± 12.7%, p < 0.001) but no significant difference in IJVD or IJVCCI. REPLETED had greater 24FR than NONREPLETED (2503 ± 1751 mL vs. 1,243 ± 1,130 mL, p = 0.003). Receiver operating characteristic analysis indicates IVCDMIN predicted 24FR (area under the curve [AUC], 0.74; 95% confidence interval [CI], 0.64-0.84; p < 0.001) as did IVCCI (AUC, 0.75; 95% CI, 0.65-0.85; p < 0.001) but not IJVDMIN (AUC, 0.48; 95% CI, 0.24-0.60; p = 0.747) or IJVCI (AUC, 0.54; 95% CI, 0.42-0.67; p = 0.591). CONCLUSION: Ultrasound assessed IVCDMIN and IVCCI response initial resuscitation predicts 24-hour fluid resuscitation requirements. LEVEL OF EVIDENCE: Diagnostic tests or criteria, level II.

The safety and efficacy of hypovolemic phlebotomy on blood loss and transfusion in liver surgery: a systematic review and meta-analysis.

BACKGROUND: Hypovolemic phlebotomy (HP) is a novel intervention that involves intraoperative removal of whole blood (7-10 mL/kg) without volume replacement. The subsequent central venous pressure (CVP) reduction is hypothesized to decrease blood loss and the need for blood transfusion. The objective was to conduct a systematic assessment of the safety and efficacy of HP on blood loss and transfusion in the liver surgery literature. METHODS: MEDLINE, EMBASE, and Cochrane Library databases were searched. Outcomes of interest included blood loss, allogenic red blood cell transfusion, postoperative adverse events, and CVP change. A qualitative synthesis and meta-analysis were performed as appropriate. RESULTS: Four cohort studies, one case series, and three randomized controlled trials involving 2255 patients were included. Meta-analysis of studies involving liver resections for any indication (n = 6) found no difference in transfusion (OR 0.38, p = 0.12) or incidence of adverse events with HP compared to non-use. Pooling of studies involving liver resections for an underlying pathology (n = 4) revealed HP was associated with significant reduction in transfusion (OR 0.25, p = 0.03) but no differences in blood loss (-173 mL, p = 0.17). CONCLUSION: This review suggests HP is safe and associated with decreased transfusion in patients undergoing liver surgery. It supports further investigation.

Acute kidney injury due to high-output external biliary drainage in a patient with malignant obstructive jaundice: a case report.

BACKGROUND: Persistent high output is a rare but potentially serious complication of percutaneous biliary drainage. CASE PRESENTATION: A 68-year-old Sinhalese woman with a palliative self-expanding metal stent placed for an inoperable hilar cholangiocarcinoma presented with worsening obstructive jaundice. Ultrasonography showed intrahepatic duct dilatation with the self-expanding metal stent in situ. Since this was indicative of a blocked stent, percutaneous transhepatic cholangiogram-guided internal biliary stenting through the self-expanding metal stent was attempted and failed. Therefore, an external biliary drain was left in the dilated biliary system. Post procedure, she developed a high biliary output of 3-4 liters per day and went into oliguric acute kidney injury with metabolic acidosis, most probably due to inadequate fluid replacement and hypovolemia. CONCLUSION: Although the mechanism by which this occurs in some cases is unclear, early identification and prompt fluid resuscitation prevent acute kidney injury. The adoption of new strategies for internal drainage of long complex strictures will both prevent and ameliorate this problem.

Preoperative "R wave amplitude variation" on electrocardiogram predicts severe hypovolemia.

Preoperative fasting is essential to prevent aspiration and associated complications. However, quite often patients end up fasting for 12 h or more due to changes in the operating room schedules, delays, and postponements. Preoperative fasting may lead to a fluid deficit, which may contribute to perioperative discomfort and morbidity. We report a case of 44-year-old female posted for total mastectomy with axillary clearance for carcinoma breast, with prolonged fasting where preoperative R wave amplitude variation along with associated changes in the plethysmograph was noticed on the monitor. 500 milliliters of lactated ringer solution was administered before induction of anesthesia, by the time R wave amplitude variation decreased. Variations in plethysmography became normal after 1 L of fluid administration after induction of anesthesia. Gross R wave amplitude variation is not a very common finding and may predict severe hypovolemia in preoperative area in prolonged fasting patients.

Trigeminal Nerve Stimulation: A Novel Method of Resuscitation for Hemorrhagic Shock.

OBJECTIVES: To determine if trigeminal nerve stimulation can ameliorate the consequences of acute blood loss and improve survival after severe hemorrhagic shock. DESIGN: Animal study. SETTING: University research laboratory. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: Severe hemorrhagic shock was induced in rats by withdrawing blood until the mean arterial blood pressure reached 27 ± 1 mm Hg for the first 5 minutes and then maintained at 27 ± 2 mm Hg for 30 minutes. The rats were randomly assigned to either control, vehicle, or trigeminal nerve stimulation treatment groups. The effects of trigeminal nerve stimulation on survival rate, autonomic nervous system activity, hemodynamics, brain perfusion, catecholamine release, and systemic inflammation after severe hemorrhagic shock in the absence of fluid resuscitation were analyzed. MEASUREMENTS AND MAIN RESULTS: Trigeminal nerve stimulation significantly increased the short-term survival of rats following severe hemorrhagic shock in the absence of fluid resuscitation. The survival rate at 60 minutes was 90% in trigeminal nerve stimulation treatment group whereas 0% in control group (p < 0.001). Trigeminal nerve stimulation elicited strong synergistic coactivation of the sympathetic and parasympathetic nervous system as measured by heart rate variability. Without volume expansion with fluid resuscitation, trigeminal nerve stimulation significantly attenuated sympathetic hyperactivity paralleled by increase in parasympathetic tone, delayed hemodynamic decompensation, and improved brain perfusion following severe hemorrhagic shock. Furthermore, trigeminal nerve stimulation generated sympathetically mediated low-frequency oscillatory patterns of systemic blood pressure associated with an increased tolerance to central hypovolemia and increased levels of circulating norepinephrine levels. Trigeminal nerve stimulation also decreased systemic inflammation compared with the vehicle. CONCLUSIONS: Trigeminal nerve stimulation was explored as a novel resuscitation strategy in an animal model of hemorrhagic shock. The results of this study showed that the stimulation of trigeminal nerve modulates both sympathetic and parasympathetic nervous system activity to activate an endogenous pressor response, improve cerebral perfusion, and decrease inflammation, thereby improving survival.

Gastrointestinal stromal tumor leading to acute abdomen and hypovolemic shock in a trauma patient.

Gastrointestinal stromal tumors (GISTs) are among the rare tumors of gastrointestinal (GI) tract. GISTs occur respectively in the stomach, small intestines, colon and rectum, omentum and mesentery, esophagus, retroperitoneal space, and abdominal cavity. However, they may occur anywhere along the GI tract. Typically, these tumors generally do not cause symptoms; however symptomatic patients may show stomach pain, GI bleeding, and palpable abdominal masses. These patients usually undergo surgery for obstruction symptoms or some other diagnosis. Our patient was admitted to the emergency department with acute abdomen and hypovolemic shock due to fall. The patient underwent emergency surgery, which revealed active bleeding from a stomach tumor showing an exophytic pattern of growth. This patient was a 32-year-old male, and blood tests revealed a white blood cell count of 23.500/mm³ and a hemoglobin level of 7.9 gr/dL. The heart rate was 110 beats/minute. The chest radiograph showed no subdiaphragmatic free air, and abdominal ultrasound showed impression of a mass that could not be distinguished from the liver, along with closed perforation or hemangioma. During the surgical procedure, 1200 cc of blood was suctioned, and the exophytic tumor was removed completely. Histological analysis of the tumor showed GIST, and it was considered to be a ruptured tumor by the oncology consultant. The patient was applied imatinib for 3 years after the surgery, and the disease did not re-occur during this period. Our goal in this case study is to emphasize that trauma may not be necessarily the cause of acute abdomen for emergency patients but that it also may be caused by hypotension-associated hypovolemic shock or other causes, bleeding from a GIST along with tumor torsion.

Effect of fluid challenge on renal resistive index after major orthopaedic surgery: A prospective observational study using Doppler ultrasonography.

BACKGROUND: A postoperative renal resistive index (RRI)>0.70 has the best threshold to early predict acute kidney injury (AKI). The response of RRI to a postoperative fluid challenge (FC) is unknown. The aim of our study was to assess the impact of a FC on RRI in suspected hypovolaemia patients after orthopaedic surgery. DESIGN: In this single-centre observational study, we prospectively screened 156 patients in the recovery room after having undergone a hip or knee replacement. INTERVENTIONS: Forty-six patients with a RRI>0.70 and requiring FC were included. RRI and cardiac output (CO) were measured before and immediately after a fluid challenge with 500mL of isotonic saline. A decrease in RRI>5% was considered significant (renal responders). RESULTS: Overall, FC resulted in a consistent decrease in RRI (from 0.74 [0.72-0.79] to 0.70 [0.68-0.73], P<0.01). Thirty-four patients (74%) showed a significant decrease in their RRI (from 0.74 [0.73-0.79] to 0.69 [0.67-0.72], P<0.05, versus non-responders: from 0.73 [0.72-0.75] to 0.72 [0.71-0.79], P=NS). CO increased equally among renal responders and non-responders (P=0.56). No correlation was found between changes in RRI and CO (r2=0.04; P=0.064). AKI was more common in renal non-responders (7/12) than in responders (3/34, P=0.001). CONCLUSIONS: After major orthopaedic surgery, a FC can decrease RRI in suspected hypovolaemia patients at risk of postoperative AKI, but the changes are not correlated to changes in CO. Decreases in RRI were associated with better renal outcome.

Hypovolemic phlebotomy in liver surgery is associated with decreased red blood cell transfusion.

BACKGROUND: Perioperative red blood cell (RBC) transfusion is associated with poor outcomes in liver surgery. Hypovolemic phlebotomy (HP) is a novel intervention hypothesized to decrease transfusion requirements. The objective of this study was to examine this hypothesis. METHODS: Consecutive patients who underwent liver resection at one institution (2010-2016) were included. Factors found to be predictive of transfusion on univariate analysis and those previously published were modeled using multivariate logistic regression. RESULTS: A total of 361 patients underwent liver resection (50% major). HP was performed in 45 patients. Phlebotomized patients had a greater proportion of primary malignancy (31% vs 18%) and major resection (84% vs 45%). Blood loss was significantly lower with phlebotomy in major resections (400 vs 700 mL). Nadir central venous pressure was significantly lower with HP (2.5 vs 5 cm H2O). On multivariate logistic regression, HP (OR 0.20, 95% CI 0.068-0.57, p = 0.0029), major liver resection (OR 2.91, 95% CI 1.64-5.18, p = 0.0003), preoperative hemoglobin < 125 g/L (OR 6.02, 95% CI 3.44-10.56, p < 0.0001), and underlying liver disease (OR 2.24, 95% CI 1.27-3.95, p = 0.0051) were significantly associated with perioperative RBC transfusion. CONCLUSION: Hypovolemic phlebotomy appears to be strongly associated with a reduction in RBC transfusion requirements in liver resection, independent of other known risk factors.

A novel etiology for craniospinal hypovolemia: a case of inferior vena cava obstruction.

The authors report on a patient with craniospinal hypovolemia and inferior vena cava obstruction, and describe how the two conditions may be linked. This unique report further advances the emerging literature on spinal CSF venous fistulae.