Bedside monitoring of circulating blood volume after subarachnoid hemorrhage

Hemodynamic Monitoring in Patients With Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis

Aneurysmal subarachnoid hemorrhage (aSAH) often causes cardiopulmonary dysfunction. Therapeutic strategies can be guided by standard (invasive arterial/central venous pressure measurements, fluid balance assessment), and/or advanced (pulse index continuous cardiac output, pulse dye densitometry, pulmonary artery catheterization) hemodynamic monitoring. We conducted a systematic review and meta-analysis of the literature to determine whether standard compared with advanced hemodynamic monitoring can improve patient management and clinical outcomes after aSAH. A literature search was performed for articles published between January 1, 2000 and January 1, 2019. Studies involving aSAH patients admitted to the intensive care unit and subjected to any type of hemodynamic monitoring were included. A total of 14 studies were selected for the qualitative synthesis and 3 randomized controlled trials, comparing standard versus advanced hemodynamic monitoring, for meta-analysis. The incidence of delayed cerebral ischemia was lower in the advanced compared with standard hemodynamic monitoring group (relative risk [RR]=0.71, 95% confidence interval [CI]=0.52-0.99; P=0.044), but there were no differences in neurological outcome (RR=0.83, 95% CI=0.64-1.06; P=0.14), pulmonary edema onset (RR=0.44, 95% CI=0.05-3.92; P=0.46), or fluid intake (mean difference=-169 mL; 95% CI=-1463 to 1126 mL; P=0.8) between the 2 groups. In summary, this systematic review and meta-analysis found only low-quality evidence to support the use of advanced hemodynamic monitoring in selected aSAH patients. Because of the small number and low quality of studies available for inclusion in the review, further studies are required to investigate the impact of standard and advanced hemodynamic monitoring-guided management on aSAH outcomes.

Hemorrhagic Complication in Surgical Resection for Massive Plexiform Neurofibroma in Body Trunk: The Flow-Void Sign as a Predictor and Preoperative Embolization as Prevention

BACKGROUND

Plexiform neurofibromas (PNs) are highly vascularized and potentially malignant tumors. Surgical resection of a PN can be complicated by perioperative hemorrhagic events (PHE), including excessive intraoperative blood loss and postoperative hematoma at the surgical site. This study aimed to evaluate the predictive factors of PHE and the usefulness of preoperative embolization for PN.

MATERIALS AND METHODS

Consecutive surgical resections of 24 massive PNs in the body trunk with a maximum diameter > 5 cm in 22 patients between January 2015 and December 2020 were reviewed. Patient demographics, laboratory analyses, MRI findings, preoperative transcatheter arterial embolization (TAE), and pathological findings were evaluated between PNs with and without PHE, which consists of intraoperative blood loss over 15% of their estimated total blood volume and/or postoperative hematoma requiring surgical intervention or blood transfusion.

RESULTS

PHE was observed in 7 out of 24 PNs (29.2%), with 5 events of excessive intraoperative bleeding and 2 postoperative hematomas. The PHE group (n = 7) showed a significantly higher flow-void effect inside the tumor on preoperative MRI than the non-PHE group (n = 17) (P = 0.0186). Preoperative TAE was not associated with PHE occurrence for the 24 PNs; however, it significantly reduced the PHE risk by 12 PNs with a flow-void sign (P = 0.00126). Other characteristics showed no significant differences between groups.

CONCLUSION

The flow-void sign on MRI can be the only predictive factor of PHE in surgical resection for massive PNs in the body trunk. Preoperative TAE can reduce the PHE risk for PNs with a flow-void sign.

Bioreactance-Based Noninvasive Fluid Responsiveness and Cardiac Output Monitoring: A Pilot Study in Patients with Aneurysmal Subarachnoid Hemorrhage and Literature Review

Management of volume status, arterial blood pressure, and cardiac output are core elements in approaching the patients with aneurysmal subarachnoid hemorrhage (SAH). For the prevention and treatment of delayed cerebral ischemia (DCI), euvolemia is advocated and caution is made towards the avoidance of hypervolemia. Induced hypertension and cardiac output augmentation are the mainstays of medical management during active DCI, whereas the older triple-H paradigm has fallen out of favor due to lack of demonstrable physiological or clinical benefits and serious concern for adverse effects such as pulmonary edema and multiorgan system dysfunction. Furthermore, insight into clinical hemodynamics of patients with SAH becomes salient when one considers the frequently associated cardiac and pulmonary manifestations of the disease such as SAH-associated cardiomyopathy and neurogenic pulmonary edema. In terms of fluid and volume targets, less attention has been paid to dynamic markers of fluid responsiveness despite the well-established, in the general critical care literature, superiority of these as compared to traditionally used static markers such as central venous pressure (CVP). Based on this literature and sound pathophysiologic reasoning, reliance on static markers (such as CVP) is unjustified when one attempts to assess strategies augmenting stroke volume (SV), arterial blood pressure, and oxygen delivery. There are several options for continuous bedside cardiorespiratory monitoring and optimization of SAH patients. We, here, review a noninvasive monitoring technique based on thoracic bioreactance and focusing on continuous cardiac output and fluid responsiveness markers.

Pre-operative haemodynamic monitoring and resuscitation in hip fracture patients: Protocol for a prospective observational study

BACKGROUND

In a frail patient group often suffering from dehydration, hip fracture is potentially fatal partly because of the blood loss and thus deteriorated circulation. An important goal for haemodynamic monitoring and resuscitation is early detection of insufficient tissue perfusion. "The peripheral perfusion index" reflects changes in peripheral perfusion and blood volume. We hypothesize that hip fracture patients are hypovolaemic with poor peripheral perfusion and accordingly respond to controlled fluid resuscitation. The peripheral perfusion index might reflect restricted tissue perfusion in spite of stable central haemodynamic variables.

METHODS

This prospective observational study assess to what extend hip fracture patients suffer from hypovolaemia and respond to a stroke volume-guided fluid challenge. The secondary objectives are to evaluate correlation between the non-invasive peripheral perfusion index and minimally invasive measures of stroke volume, changes in blood volume and near-infrared spectroscopy determined tissue- and cerebral oxygenation and to compare results to prevalence of post-operative complications including mortality. We will include 50 patients (>65 years) presenting a hip fracture and treated in a multimodal fast-track regimen when written informed consent is available.

DISCUSSION

This is likely the first study to address pre-operative haemodynamic monitoring and resuscitation in hip fracture patients where adequate resuscitation is easily missed. We aim to evaluate feasibility of pre-operative stroke volume-guided haemodynamic optimization in the context of minimally- and non-invasive monitoring of peripheral perfusion and measure of blood volume.

Serum Lactic Acid Following Aneurysmal Subarachnoid Hemorrhage Is a Marker of Disease Severity but Is Not Associated With Hospital Outcomes

Background: Following aneurysmal subarachnoid hemorrhage, peripherally-drawn lactic acid has been associated with poor outcomes; however, its clinical significance is unknown. We investigated admission factors and patient outcomes associated with serum lactic acid in this population.

Methods: This was a retrospective observational study of 105 consecutive patients with serum lactate collected within 24 h of admission. Primary objectives were to determine the incidence of admission lactic acidemia, and factors positively and negatively associated with lactate levels. We also sought to determine if admission lactic acidemia was associated with patient outcomes, including vasospasm, delayed cerebral ischemia, mortality, and discharge disposition.

Results: Admission serum lactic acid was elevated in 56 patients (53% of the cohort). Levels were positively associated with Hunt & Hess and modified Fisher grade, glucose, troponin I and white blood cell counts, and negatively associated with GCS and ventilator-free days. Admission lactate was not associated with the development of vasospasm or delayed cerebral ischemia. Patients with elevated lactic acid more often died during hospitalization, and less often were discharged home. After adjusting for other predictors of poor outcome, the adjusted odds of inpatient mortality (OR 0.97, 95% CI 0.79–1.20; p = 0.80) and discharge to home (OR 1.00, 95% CI 0.80–1.26; p = 0.97) was not associated with admission lactic acid.

Conclusions: Early serum lactic acid elevation is common following aneurysmal subarachnoid hemorrhage and is associated with the clinical and radiographic grade of hemorrhage. Levels did not independently predict short-term outcomes when adjusted for established predictors of poor outcome. Further study is needed to determine the clinical significance of peripherally-drawn lactic acid in aneurysmal subarachnoid hemorrhage.

Impact of restrictive fluid protocol on hypoxemia after aneurysmal subarachnoid hemorrhage

PURPOSE

In patients with aneurysmal subarachnoid hemorrhage (aSAH), acute cardiac dysfunction and triple-H-therapy, can lead to hypoxemia. Our aim was to assess impact of a protocoled fluid restrictive approach on hypoxemia in these patients.

METHODS

We included prospectively ICU patients with aSAH admitted within 24h after the bleed. The study was divided into 2 phases. The first phase, from January to December 2012, was designated as control group (group C). The second phase, from February 2014 to January 2015, was designated as study group (group S). Between these periods, a protocoled fluid intake approach was implemented to maintain as low as possible the cumulative fluid balances.

RESULTS

Effective fluid restriction was obtained: at day 3 cumulative fluid balances were respectively for group C and group S, 1559±2402ml and 759±1855ml (p=0.04); and 2211±4918ml vs 529±2806ml (p=0.04) at day 7. We observed reduction in proportion of hypoxemic patient in group S compared to group C, at day 3 (22% vs 40%, p=0.047) and at day 7 (28% vs 57%, p=0.007).

CONCLUSIONS

Fluid restrictive management of patients with aSAH decreases number of hypoxemic patients at day 3 and day 7.

Preoperative hypoalbuminemia and anemia as predictors of transfusion in radical nephrectomy for renal cell carcinoma: a retrospective study

Background

The only curative therapy for renal cell carcinoma is the complete removal of malignant tissue. Surgical bleeding during radical nephrectomy may require blood transfusion. Blood transfusion, however, is associated with postoperative morbidity and mortality. This study investigated predictive factors of transfusion requirement in patients undergoing radical nephrectomy, as well as the effects of transfusion on postoperative outcomes.

Methods

This study retrospectively enrolled 526 patients who underwent open radical nephrectomy for renal cell carcinoma between 2010 and 2012. Univariate and multivariate logistic regression analyses were used to determine independent predictive factors of a requirement for packed red blood cell (PRBC) transfusion. Postoperative outcomes included an admission to the intensive care unit (ICU) and lengths of ICU and hospital stay.

Results

Of the 526 patients, 93 (17.7 %) required PRBC transfusion, with these patients requiring a mean 5.5 units. Preoperative hypoalbuminemia (serum albumin <3.5 g/dL) was observed in 75 (14.3 %) patients, and preoperative anemia (hemoglobin <12.0 g/dL) in 121 (23.0 %). Multivariate logistic regression analysis showed that preoperative hypoalbuminemia, preoperative anemia, and a high cancer stage were independent factors significantly associated with PRBC transfusion in open radical nephrectomy. The transfused group had higher incidence of ICU admission and longer lengths of ICU and hospital stay than the non-transfused group.

Conclusions

Preoperative hypoalbuminemia and anemia are important predictors of PRBC transfusion during radical nephrectomy for renal cell carcinoma. Furthermore, transfusion is associated with poor postoperative outcomes.

Effect of triple-h prophylaxis on global end-diastolic volume and clinical outcomes in patients with aneurysmal subarachnoid hemorrhage

BACKGROUND

Although prophylactic triple-H therapy has been used in a number of institutions globally to prevent delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH), limited evidence is available for the effectiveness of triple-H therapy on hemodynamic variables. Recent studies have suggested an association between low global end-diastolic volume index (GEDI), measured using a transpulmonary thermodilution method, and DCI onset. The current study aimed at assessing the effects of prophylactic triple-H therapy on GEDI.

METHODS

This prospective multicenter study included aneurysmal SAH patients admitted to 9 hospitals in Japan. The decision to administer prophylactic triple-H therapy and the management protocols were left to the physician in charge (physician-directed therapy) of each participating institution. The primary endpoints were the changes in the hemodynamic variables as analyzed using a generalized linear mixed model.

RESULTS

Of 178 patients, 62 (34.8 %) received prophylactic triple-H therapy and 116 (65.2 %) did not. DCI was observed in 35 patients (19.7 %), with no significant difference between the two groups [15 (24.2 %) vs. 20 (17.2 %), p = 0.27]. Although a greater amount of fluid (p < 0.001) and a higher mean arterial pressure (p = 0.005) were observed in the triple-H group, no significant difference was observed between the groups in GEDI (p = 0.81) or cardiac output (p = 0.62).

CONCLUSIONS

Physician-directed prophylactic triple-H administration was not associated with improved clinical outcomes or quantitative hemodynamic indicators for intravascular volume. Further, GEDI-directed intervention studies are warranted to better define management algorithms for SAH patients with the aim of preventing DCI.

Optimal range of global end-diastolic volume for fluid management after aneurysmal subarachnoid hemorrhage: a multicenter prospective cohort study

OBJECTIVES

Limited evidence supports the use of hemodynamic variables that correlate with delayed cerebral ischemia or pulmonary edema after aneurysmal subarachnoid hemorrhage. The aim of this study was to identify those hemodynamic variables that are associated with delayed cerebral ischemia and pulmonary edema after subarachnoid hemorrhage.

DESIGN

A multicenter prospective cohort study.

SETTING

Nine university hospitals in Japan.

PATIENTS

A total of 180 patients with aneurysmal subarachnoid hemorrhage.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were prospectively monitored using a transpulmonary thermodilution system in the 14 days following subarachnoid hemorrhage. Delayed cerebral ischemia was developed in 35 patients (19.4%) and severe pulmonary edema was developed in 47 patients (26.1%). Using the Cox proportional hazards model, the mean global end-diastolic volume index (normal range, 680-800 mL/m) was the independent factor associated with the occurrence of delayed cerebral ischemia (hazard ratio, 0.74; 95% CI, 0.60-0.93; p = 0.008). Significant differences in global end-diastolic volume index were detected between the delayed cerebral ischemia and non-delayed cerebral ischemia groups (783 ± 25 mL/m vs 870 ± 14 mL/m; p = 0.007). The global end-diastolic volume index threshold that best correlated with delayed cerebral ischemia was less than 822 mL/m, as determined by receiver operating characteristic curves. Analysis of the Cox proportional hazards model indicated that the mean global end-diastolic volume index was the independent factor that associated with the occurrence of pulmonary edema (hazard ratio, 1.31; 95% CI, 1.02-1.71; p = 0.03). Furthermore, a significant positive correlation was identified between global end-diastolic volume index and extravascular lung water (r = 0.46; p < 0.001). The global end-diastolic volume index threshold that best correlated with severe pulmonary edema was greater than 921 mL/m.

CONCLUSIONS

Our findings suggest that global end-diastolic volume index impacts both delayed cerebral ischemia and pulmonary edema after subarachnoid hemorrhage. Maintaining global end-diastolic volume index slightly above normal levels has promise as a fluid management goal during the treatment of subarachnoid hemorrhage.

Early intensive versus minimally invasive approach to postoperative hemodynamic management after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

The results of previous studies suggest that early goal-directed fluid therapy (EGDT) reduces delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage, but the effects of EGDT on clinical outcomes are still unclear. This study aimed to determine whether EGDT improves outcomes compared with standard less-invasive hemodynamic therapy.

METHODS

This study included 160 patients treated within 24 hours after subarachnoid hemorrhage, randomized to receive either (1) EGDT guided by preload volume and cardiac output monitored by transpulmonary thermodilution (treatment group) or (2) standard therapy guided by fluid balance or central venous pressure, assisted by uncalibrated less-invasive cardiac output monitoring during hyperdynamic therapy in patients with clinical or radiological indications of DCI (control group). DCI determined by clinical or radiological findings and functional outcome determined by the modified Rankin Scale score at 3 months were compared between groups.

RESULTS

For all clinical grades combined, there were no significant differences in the rates of DCI (33% versus 42%; P=0.33) or modified Rankin Scale score of 0 to 3 at 3 months (67% versus 57%; P=0.22) between the 2 groups. For patients with poor clinical grade, those who received EGDT had a significantly lower rate of DCI (5% versus 14%; P=0.036), modified Rankin Scale score of 0 to 3 at 3 months (52% versus 36%; P=0.026), and shorter length of intensive care unit stay (14 versus 17 days; P=0.043) than those who received standard therapy.

CONCLUSIONS

EGDT is beneficial for reducing DCI and improving postoperative functional outcome in patients with poor clinical grade.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: UMIN000007509.

Monitoring systems and quantitative measurement of biomolecules for the management of trauma

Continued high morbidity and complications due to trauma related hemorrhage underscores the fact that our understanding of the detailed molecular events of trauma are inadequate to bring life-saving changes to practice. The current state of efficacy and advances in biomedical microdevice technology for trauma diagnostics concerning hemorrhage and hemorrhagic shock was considered with respect to vital signs and metabolic biomarkers. Tachycardia and hypotension are markers of hemorrhagic shock in decompensated trauma patients. Base deficit has been predicative of injury severity at hospital admission. Tissue oxygen saturation has been predicative of onset of multiple organ dysfunction syndrome. Blood potassium levels increase with onset of hemorrhagic shock. Lactate is a surrogate for tissue hypoxia and its clearance predicts mortality. Triage glucose measurements have been shown to be specific in predicting major injuries. No vital sign has yet to be proven effective as an independent predictor of trauma severity. Point of care (POC) devices allow for rapid results, easy sample preparation and processing, small sample volumes, small footprint, multifunctional analysis, and low cost. Advances in the field of in-vivo biosensors has provided a much needed platform by which trauma related metabolites can be monitored easily, rapidly and continuously. Multi-analyte monitoring biosensors have the potential to explore areas still undiscovered in the realm of trauma physiology.

A randomized double-blind clinical trial of tourniquet application strategies for total knee arthroplasty

PURPOSE

The optimal timing of pneumatic lower limb tourniquet application during primary elective total knee arthroplasty surgery (TKA) is a matter of debate. Most previous reports have failed to show significant differences between different tourniquet timings. The aim of the work was to determine how three strategies of lower limb pneumatic tourniquet application affect the outcome for TKA patients.

METHODS

Forty-three patients who undergo TKA were randomized into one of the three groups, and 36 of these patients completed the study. The tourniquet was inflated just before incision and deflated after the hardening of the cement for twelve patients (Group 1), it was inflated just before cement application and deflated after its hardening for another twelve patients (Group 2), and it was inflated before incision and deflated after the last suture of the skin for a further twelve patients (Group 3). Fit-to-discharge criteria and six methods for calculating estimated blood loss were used.

RESULTS

The estimated blood loss in Group 1 was lower than in Group 2, as determined by six methods of calculation (p < 0.05). Estimated blood loss in Group 3 was lower than in Group 2, as determined by one method (p = 0.050). The mobilization performance in Group 1 was better than in Group 2 (p = 0.023) and in Group 3 (p = 0.033). Group 1 was better fit to discharge than Group 3 (p = 0.030).

CONCLUSIONS

Inflation of an automatic pneumatic lower limb tourniquet before skin incision and its deflation after hardening of cement tends to give better outcomes in TKA patients during six postoperative days. The estimated blood loss was highest when the tourniquet was inflated just before cement application and deflated after its hardening.

Appetite loss may be induced by lower serum ghrelin and higher serum leptin concentrations in subarachnoid hemorrhage patients

BACKGROUND

Patients with aneurysmal subarachnoid hemorrhage (SAH) typically develop appetite loss. However, the mechanisms regulating appetite are not understood. Ghrelin and leptin, both of which signal nutritional status and energy storage levels to the hypothalamus, are essential elements of the appetite system. Thus, the goal of this study was to investigate the relationship between appetite and ghrelin and leptin concentrations in patients with SAH.

METHODS

Blood plasma or serum profiles and appetite status were measured in 19 patients with SAH who underwent aneurysmal clipping within 48 hours of SAH onset. Appetite status was measured using dietary oral calorie intake. All outcome variables were measured at an early (day 3) and late (day 8) time point after SAH onset (day 0).

RESULTS

Of the 19 patients studied, 6 (31.6%) showed lower dietary oral calorie intake at the late time point than at the early time point. In these patients with appetite loss, plasma hemoglobin (P < 0.02), albumin (P < 0.01), glucose (P < 0.01), plasma insulin (P < 0.04), and serum ghrelin (P < 0.03) concentrations were lower at the late time point than at the early time point. Serum leptin was higher at the late time point than at the early time point (P < 0.02).

CONCLUSION

In SAH patients, appetite loss may be induced by lower serum ghrelin and higher serum leptin concentrations resulting from high plasma glucose and insulin levels due to a catecholamine surge following SAH.

Global end-diastolic volume is associated with the occurrence of delayed cerebral ischemia and pulmonary edema after subarachnoid hemorrhage

Predictive variables of delayed cerebral ischemia (DCI) and pulmonary edema following subarachnoid hemorrhage (SAH) remain unknown. We aimed to determine associations between transpulmonary thermodilution-derived variables and DCI and pulmonary edema occurrence after SAH. We reviewed 34 consecutive SAH patients monitored by the PiCCO system. Six patients developed DCI at 7 days after SAH on average; 28 did not (non-DCI). We compared the variable measures for 1 day before DCI occurred (DCI day -1) in the DCI group and 6 days after SAH (non-DCI day -1) in the non-DCI group for control. The mean value of the global end-diastolic volume index (GEDI) for DCI day -1 was lower than that for non-DCI day -1 (676 ± 65 vs. 872 ± 85 mL/m, P = 0.04). Central venous pressure (CVP) was not significantly different (7.8 ± 3.1 vs. 9.4 ± 1.9 cm H2O, P = 0.45). At day -1 for both DCI and non-DCI, 11 patients (32%) had pulmonary edema. Global end-diastolic volume index was significantly higher in patients with pulmonary edema than in those without this condition (947 ± 126 vs. 766 ± 81 mL/m, P = 0.02); CVP was not significantly different (8.7 ± 2.8 vs. 9.2 ± 2.1 cm H2O, P = 0.78). Although significant correlation was found between extravascular lung water (EVLW) measures and GEDI (r = 0.58, P = 0.001), EVLW and CVP were not correlated (r = 0.03, P = 0.88). Thus, GEDI might be associated with DCI occurrence and EVLW accumulation after SAH.

Is the circulating plasma volume sufficiently maintained? Fluid management of an aneurysmal subarachnoid hemorrhage in the acute phase

Cerebral vasospasm is a well-known cause of mortality and morbidity following aneurysmal subarachnoid hemorrhage (SAH). Prevention of symptomatic cerebral vasospasm is the basic management after SAH. Numerous pharmaceutical therapies and endovascular treatments are available against cerebral vasospasm, but none of them have so far proven to improve the outcome. We have focused on maintaining the circulation volume in order to prevent cerebral vasospasm. But to maintain the central venous pressure, huge infusion volume was required, and hyponatremia was frequently observed due to natriuresis and osmotic diuresis. Excessive natriuresis and diuresis cannot be managed through sodium and water replacement, since sodium replacement induces further natriuresis and diuresis (desalination), and water replacement induces hyponatremia. We therefore administered fludrocortisone and hydrocortisone to inhibit excessive natriuresis and diuresis. The efficacy of sodium reabsorption therapy is extremely high to maintain the circulation volume that might have a therapeutic effect to prevent cerebral vasospasm. In this article, we review our institution's experience regarding the management of patients with aneurysmal SAH and also discuss the importance of water and sodium balance when managing such patients.

Intravenous fluid administration may improve post-operative course of patients with chronic subdural hematoma: a retrospective study

Background

The treatment of chronic subdural hematoma (cSDH) is still charged of significant risk of hematoma recurrence. Patient-related predictors and the surgical procedures themselves have been addressed in many studies. In contrast, postoperative management has infrequently been subjected to detailed analysis. Moreover variable intravenous fluid administration (IFA) was not reported in literature till now in the context of cSDH treatment.

Methodology/Principal Findings

A total of 45 patients with cSDH were operated in our department via two burr hole craniostomy within one calendar year. Downward drainage was routinely left in hematoma cavity for a one day. Independent variables selected for the analysis were related to various aspects of patient management, including IFA. Two dependent variables were chosen as measure of clinical course: the rate of hematoma recurrence (RHR) and neurological status at discharge from hospital expressed in points of Glasgow Outcome Scale (GOS). Univariate and multivariate regression analyses were performed. Hematoma recurrence with subsequent evacuation occurred in 7 (15%) patients.

Univariate regression analysis revealed that length of IFA after surgery influenced both dependent variables: RHR (p = 0.045) and GOS (p = 0.023). Multivariate regression performed by backward elimination method confirmed that IFA is a sole independent factor influencing RHR. Post hoc dichotomous division of patients revealed that those receiving at least 2000 ml/day over 3 day period revealed lower RHR than the group with less intensive IFA. (p = 0.031).

Conclusions/Significance

IFA has been found to be a sole factor influencing both: RHR and GOS. Based on those results we may recommend administration of at least 2000 ml per 3 days post-operatively to decrease the risk of hematoma recurrence.

Advanced hemodynamic monitoring: principles and practice in neurocritical care

Advanced hemodynamic monitoring is necessary for many patients with acute brain and/or spinal cord injury. Optimizing cerebral and systemic physiology requires multi-organ system function monitoring. Hemodynamic manipulations are cardinal among interventions to regulate cerebral perfusion pressure and cerebral blood flow. The pulmonary artery catheter is not any more the sole tool available; less invasive and potentially more accurate methodologies have been developed and employed in the operating room and among diverse critically ill populations. These include transpulmonary thermodilution, arterial pressure pulse contour, and waveform analysis and bedside critical care ultrasound. A thorough understanding of hemodynamics and of the available monitoring modalities is an essential skill for the neurointensivist.

Monitoring of volume status after subarachnoid hemorrhage

Hypovolemia is common after subarachnoid hemorrhage, and fluid imbalance negatively affects clinical outcome. Standard bedside volume measures fail to adequately assess fluid status after subarachnoid hemorrhage. An electronic literature search of original research studies evaluating fluid status after subarachnoid hemorrhage was conducted for English language articles published through October 2010. Sixteen articles were included in this review, with seven articles produced by two research groups. These studies highlight that fluid status is often affected and difficult to assess after subarachnoid hemorrhage. Both non-invasive and invasive monitors may be used to more accurately define volume status.

Pulmonary edema and blood volume after aneurysmal subarachnoid hemorrhage: a prospective observational study

Introduction

Pulmonary edema (PED) is a severe complication after aneurysmal subarachnoid hemorrhage (SAH). PED is often treated with diuretics and a reduction in fluid intake, but this may cause intravascular volume depletion, which is associated with secondary ischemia after SAH. We prospectively studied intravascular volume in SAH patients with and without PED.

Methods

Circulating blood volume (CBV) was determined daily during the first 10 days after SAH by means of pulse dye densitometry. CBV of 60-80 ml/kg was considered normal. PED was diagnosed from clinical signs and characteristic bilateral pulmonary infiltrates on the chest radiograph. We compared CBV, cardiac index, and fluid balance between patients with and without PED with weighted linear regression, taking into account only measurements from the first day after SAH through to the day on which PED was diagnosed. Differences were adjusted for age, bodyweight, and clinical condition.

Results

In total, 102 patients were included, 17 of whom developed PED after a mean of 4 days after SAH. Patients developing PED had lower mean CBV (56.6 ml/kg) than did those without PED (66.8 ml/kg). The mean difference in CBV was -11.3 ml/kg (95% CI, -16.5 to -6.1); adjusted mean difference, -8.0 ml/kg (95% CI, -14.0 to -2.0). After adjusting, no differences were found in cardiac index or fluid balance between patients with and without PED.

Conclusions

SAH patients developing pulmonary edema have a lower blood volume than do those without PED and are hypovolemic. Measures taken to counteract pulmonary edema must be balanced against the risk of worsening hypovolemia.

Trial registration

NTR1255.

Blood volume measurement with indocyanine green pulse spectrophotometry: dose and site of dye administration

Background

(1) To determine the optimal administration site and dose of indocyanine green (ICG) for blood volume measurement using pulse spectrophotometry, (2) to assess the variation in repeated blood volume measurements for patients after subarachnoid hemorrhage and (3) to evaluate the safety and efficacy of this technique in patients who were treated for an intracranial aneurysm.

Methods

Four repeated measurements of blood volume (BV) were performed in random order of bolus dose (10 mg or 25 mg ICG) and venous administration site (peripheral or central) in eight patients admitted for treatment of an intracranial aneurysm. Another five patients with subarachnoid hemorrhage underwent three repeated BV measurements with 25 mg ICG at the same administration site to assess the coefficient of variation.

Findings

The mean ± SD in BV was 4.38 ± 0.88 l (n = 25) and 4.69 ± 1.11 l (n = 26) for 10 mg and 25 mg ICG, respectively. The mean ± SD in BV was 4.59 ± 1.15 l (n = 26) and 4.48 ± 0.86 l (n = 25) for central and peripheral administration, respectively. No significant difference was found. The coefficient of variance of BV measurement with 25 mg of ICG was 7.5% (95% CI: 3–12%).

Conclusions

There is no significant difference between intravenous administration of either 10 or 25 mg ICG, and this can be injected through either a peripheral or central venous catheter. The 7.5% coefficient of variation in BV measurements determines the detectable differences using ICG pulse spectrophotometry.

Nurses' prediction of volume status after aneurysmal subarachnoid haemorrhage: a prospective cohort study

Introduction

Patients who have suffered aneurysmal subarachnoid haemorrhage (SAH) often have derangements in blood volume, contributing to poor outcome. To guide fluid management, regular assessments of volume status must be conducted. We studied the ability of nursing staff to predict hypovolaemia or hypervolaemia, based on their interpretation of available haemodynamic data.

Methods

In a prospective cohort study, intensive care unit and medium care unit nurses, currently treating patients with recent SAH, were asked to predict present volume status. For their assessment they could use all available haemodynamic parameters (for example, heart rate, blood pressure, fluid balance). The nurses' assessments were compared with the actual circulating blood volume (CBV), as measured daily with pulse dye densitometry during the first 10 days after SAH. Normovolaemia was defined as a CBV of 60 to 80 ml/kg body weight; hypovolaemia as CBV under 60 ml/kg; severe hypovolaemia as CBV under 50 ml/kg and hypervolaemia as CBV above 80 ml/kg.

Results

A total of 350 combinations of volume predictions and CBV measurements were obtained in 43 patients. Prediction of hypovolaemia had a sensitivity of 0.10 (95% confidence interval [CI] = 0.06 to 0.16) and a positive predictive value of 0.37 (95% CI = 0.23 to 0.53) for actual hypovolaemia. The prediction of hypervolaemia had a sensitivity of 0.06 (95% CI = 0.01 to 0.16) and a positive predictive value of 0.06 (95% CI = 0.02 to 0.19) for actual hypervolaemia. Mean CBV was significantly lower in instances considered hypervolaemic than in instances considered normovolaemic.

Conclusions

Assessment of haemodynamic condition in patients with SAH by intensive care unit or medium care unit nurses does not adequately predict hypovolaemia or hypervolaemia, as measured using pulse dye densitometry. Fluid therapy after SAH may require guidance with more advanced techniques than interpretation of usual haemodynamic parameters.

Hypertonic saline solutions for treatment of intracranial hypertension

PURPOSE OF REVIEW

This review aims to provide an update on recent knowledge gained on hypertonic saline solutions for the treatment of intracranial hypertension. Explanatory approaches to the mechanisms underlying the edema-reducing effects of the solutions are outlined, practical aspects of use are presented, and trials that assessed their clinical utility are highlighted.

RECENT FINDINGS

With an established trauma system, hypertonic saline added to conventional fluid resuscitation did not improve long-term outcome in multiple injury with hypotension and brain trauma. In intensive care, hypertonic saline reduced intracranial hypertension after subarachnoid haemorrhage, brain trauma, and a variety of other brain diseases, including cerebral edema in acute liver failure.

SUMMARY

Hypertonic saline solutions have evolved as an alternative to mannitol or may be used in otherwise refractory intracranial hypertension to treat raised intracranial pressure. With high osmolar loads, the efficacy of the solution is enhanced, but no simple relationship between the saline concentration and the clinical effects of a solution is established. Caution is advised with high osmolar loads because they carry increased risks for potentially deleterious consequences of hypernatremia or may induce osmotic blood-brain barrier opening with possibly harmful extravasation of the hypertonic solution into the brain tissue.

Revascularization for complex intracranial aneurysms

The modern management of intracranial aneurysms includes both constructive and deconstructive strategies to eliminate the aneurysm from the circulation. Both microsurgical and endovascular techniques are used to achieve this goal. Although most aneurysms can be eliminated from the circulation with simple clip reconstruction and/or coil insertion, some require revascularization techniques to enhance tolerance of temporary arterial occlusion during clipping of the aneurysm neck or to enable proximal occlusion or trapping. In fact, the importance of revascularization techniques has grown because of the need for complex reconstructions when endovascular therapies fail. Moreover, the safety and feasibility of bypass have progressed due to advances in neuroanesthesia, technological innovations, and ~ 5 decades of accumulating wisdom by bypass practitioners. Cerebral revascularization strategies become necessary in select patients who possess challenging vascular aneurysms due to size, shape, location, intramural thrombus, atherosclerotic plaques, aneurysm type (for example, dissecting aneurysms), vessels arising from the dome, or poor collateral vascularization when parent artery or branch occlusion is required. These techniques are used to prevent cerebral ischemia and subsequent clinical sequelae. Bypass techniques should be considered in cases in which balloon test occlusion demonstrates inadequate cerebral blood flow and in which there is a need for Hunterian ligation, trapping, or prolonged temporary occlusion. This review article will focus on decision making in bypass surgery for complex aneurysms. Specifically, the authors will review graft options, the utility of balloon test occlusion in decision making, and bypass strategies for various aneurysm types.

Nicardipine prolonged-release implants for preventing cerebral vasospasm after subarachnoid hemorrhage: effect and outcome in the first 100 patients

Vasospasm following subarachnoid hemorrhage (SAH) remains difficult to prevent despite extensive investigative efforts. Nicardipine prolonged-release implants (NPRIs) have been used to prevent vasospasm in patients with SAH since October 1999. The present study analyzed the efficacy and safety of NPRIs in 100 patients with SAH and thick subarachnoid clot (mainly Fisher group 3) treated with NPRIs (diameter 2 mm, length 10 mm, containing 4 mg of nicardipine) during surgery after clipping of the aneurysm. The number and location of pellets depended on the amount and site of the subarachnoid clot on preoperative computed tomography and on the type of craniotomy. Two to 12 pellets were implanted in the cisterns of the internal carotid artery, middle cerebral artery, and/or anterior cerebral artery, where thick clots were present and vasospasm related to delayed ischemic neurological deficit (DIND) was highly likely. Only seven patients developed DIND and five patients suffered cerebral infarction. Angiography performed on days 7-12 revealed no vasospasm in any of the arteries close to the site of NPRI placement. NPRI placement can completely prevent vasospasm in arteries within the cisterns containing thick clots, but is less effective in remote locations.

The systemic implications of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is analogous to a pathophysiological watershed, disrupting brain integrity and function and precipitating an array of systemic derangements including cardiovascular, respiratory, endocrine, hematological, and immune dysfunction. Extracerebral organ dysfunction is closely linked to the magnitude of the primary neurological insult, suggesting neurogenic, neuroendocrine and neuroimmunomodulatory mechanisms. Systemic organ involvement is associated with increased mortality and neurological impairment, even after adjustment for other outcome predictors such as the severity of the initial neurological injury. This may be a reflection of secondary brain injury precipitated by hypoxemia, circulatory failure, fever, or hyperglycemia, all of which have been linked to adverse clinical outcomes. Interventions to avert or reverse these and other perturbations need to be tested in clinical trials as they represent opportunities to improve survival and neurological recovery in patients with SAH.

Specialized neurocritical care, severity grade, and outcome of patients with aneurysmal subarachnoid hemorrhage

INTRODUCTION

To evaluate the impact of specialized neurocritical care on the population admitted to a neurovascular center and on the outcome of patients with severe aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

After exclusion of patients treated with endovascular techniques, between 1999 and 2003, 198 patients with aSAH treated with early aneurysm clipping were analysed. In 1999, a new standardized protocol for intensive care treatment was established in the Department of Neurosurgery, University Hospital Zurich. The results were compared to the earlier time period (1993-1994) immediately after introduction of early aneurysm clipping.

RESULTS

Out of 198 patients with aSAH, 90 patients (45.5%) suffered from mild aSAH World Federation of Neurosurgical Societies (WFNS) grade 1 and 2, 41 (27.3%) from aSAH WFNS grade 3, 36 (18.2%) from grade 4, and 57 (28.8%) from grade 5. From 1999 to 2003, significantly more patients with severe aSAH WFNS grade 4 and 5 underwent (further) treatment (93 out of 198 patients; 47.0%) compared to the former time-period after introduction of early surgery (23 out of 150 patients; 15.3%) (p < 0.0001). In the early series, 10 out of 23 patients (43.5%) with WFNS 4 recovered with good outcome Glasgow Outcome Score 4 and 5, whereas in the later series 23 out of 36 (63.9%) with WFNS grade 4 survived in a good functional state. Before 1999, all patients with WFNS grade 5 died or survived in a vegetative state. From 1999 to 2003, 20 out of 57 patients (35.1%) with aSAH WFNS grade 5 survived with good outcome.

CONCLUSIONS

The availability of extended specialized neurocritical care seems to induce a change within the patient population towards a higher severity grade. Patients with highgrade aSAH might benefit most from highly specialized neurocritical care treatment.

[Hemorrhagic shock]

Hemorrhagic shock is a condition produced by rapid and significant loss of blood which lead to hemodynamic instability, decreases in oxygen delivery, decreased tissue perfusion, cellular hypoxia, organ damage and can be rapidly fatal. Despite improved understanding of the pathophysiology and significant advances in technology, it remains a serious problem associated with high morbidity and mortality. Early treatment is essential but is hampered by the fact that signs and symptoms of shock appear only after the state of shock is well establish and the compensatory mechanisms have started to fail. The primary goal is to stop the bleeding and restore the intravascular volume. This review addresses the pathophysiology and treatment of haemorrhagic shock.

Anaesthesia for endovascular management of cerebral aneurysms

Subarachnoid haemorrhage due to rupture of cerebral aneurysms is a multisystem disease. Treatment of the condition in the past has relied on craniotomy and clipping of the aneurysm to prevent a recurrent haemorrhage. There is now emerging evidence to suggest that endovascular treatment of cerebral aneurysms may reduce the morbidity associated with open surgery. The anaesthetic management of interventional neuroradiology also creates new challenges due to the novel approach to treatment. Anaesthetists need to be familiar with this procedure and the management of potential complications. This review provides an overview such considerations.

Clinical review: hemorrhagic shock

This review addresses the pathophysiology and treatment of hemorrhagic shock – a condition produced by rapid and significant loss of intravascular volume, which may lead sequentially to hemodynamic instability, decreases in oxygen delivery, decreased tissue perfusion, cellular hypoxia, organ damage, and death. Hemorrhagic shock can be rapidly fatal. The primary goals are to stop the bleeding and to restore circulating blood volume. Resuscitation may well depend on the estimated severity of hemorrhage. It now appears that patients with moderate hypotension from bleeding may benefit by delaying massive fluid resuscitation until they reach a definitive care facility. On the other hand, the use of intravenous fluids, crystalloids or colloids, and blood products can be life saving in those patients who are in severe hemorrhagic shock. The optimal method of resuscitation has not been clearly established. A hemoglobin level of 7–8 g/dl appears to be an appropriate threshold for transfusion in critically ill patients with no evidence of tissue hypoxia. However, maintaining a higher hemoglobin level of 10 g/dl is a reasonable goal in actively bleeding patients, the elderly, or individuals who are at risk for myocardial infarction. Moreover, hemoglobin concentration should not be the only therapeutic guide in actively bleeding patients. Instead, therapy should be aimed at restoring intravascular volume and adequate hemodynamic parameters.