Compromised Tissue Perfusion Research Articles

OXIGENOTERAPIA HIPERBÁRICA

Hyperbaric oxygen therapy (HBOT) has aroused increasing interest as an effective therapeutic intervention in diabetic patients, especially those suffering from chronic complications such as diabetic foot ulcers. This article examines the application of HBOT in this context, highlighting its potential benefits and the mechanisms underlying its therapeutic effects. HBOT involves administering pure oxygen at a pressure higher than atmospheric, resulting in increased levels of dissolved oxygen in the blood plasma. In diabetic patients, chronic hyperglycemia can lead to blood vessel damage, compromising tissue oxygenation and delaying wound healing. HBOT aims to correct this oxygenation deficiency by delivering oxygen at high concentrations and pressures that increase oxygen diffusion in compromised tissues. Clinical studies have shown that HBOT can accelerate the healing of diabetic foot ulcers, reduce the risk of amputation, and improve the quality of life of these patients. In addition, HBOT exerts anti-inflammatory effects and promotes the formation of new blood vessels, which may be crucial to restore compromised tissue perfusion in diabetic patients. Importantly, HBOT is not a monotherapy but rather an integral part of a multidisciplinary treatment plan and should be combined with appropriate glycemic control measures, wound care, antibiotic therapy, and other interventions as needed to optimize clinical outcomes. In summary, HBOT represents a promising approach in the management of chronic complications in diabetic patients, offering potential to improve wound healing, prevent amputations, and improve quality of life. However, more research is needed to fully elucidate the mechanisms of action of HBOT and identify subgroups of patients who will benefit most from this therapy.

(503) - Myocardial Support During Low Flow Hypothermic Perfusion Does Not Compromise Tissue Perfusion of the Dependent Region

(503) - Myocardial Support During Low Flow Hypothermic Perfusion Does Not Compromise Tissue Perfusion of the Dependent Region

Vancomycin Three Ways: Multimodal Utilization of Intraoperative Antibiosis in Complex Foot and Ankle Infection

Osteomyelitis of the foot and ankle is an unfortunate, albeit pervasive, complication faced by orthopedic surgeons and their patients. Chronic osteomyelitis confers a great risk of amputation and protracted hospital admission in patients with diabetes, existing orthopedic hardware, and/or compromised tissue perfusion. The current standard of practice in the treatment of osteomyelitis is the initiation of broad antibiotic coverage followed by subsequent narrowing informed by culture data and sensitivities. While mild to moderate infections are treated with oral antibiotics, more severe infections are often treated using intravenous (IV) antibiotics. Vancomycin, in its IV form, is frequently administered intraoperatively for patients with osteomyelitis as it confers adequate coverage of common causative organisms, including staphylococcus aureus. However, given the diminished blood flow to distal extremities commonly seen in patients experiencing this complication, inadequate distribution of oral or IV antibiotics may occur. This is especially problematic, as it leads to an increased risk of recurrent infection and the ultimate need for amputation. Here, we present an alternate method of intraoperative vancomycin administration for patients with chronic osteomyelitis in the form of paste, powder, and injectable slurry. Postoperatively, oral or IV antibiotics are continued based on OR culture susceptibility. We found this to be an effective way to administer intraoperative antibiotics to ensure adequate osseous and soft tissue penetration in patients with complicated osteomyelitis of the foot and ankle. Level of Evidence: III.

Prevention of Intradialytic Hypotension in Hemodialysis Patients: Current Challenges and Future Prospects.

Intradialytic hypotension, defined as rapid decrease in systolic blood pressure of greater than or equal to 20 mmHg or in mean arterial pressure of greater than or equal to 10 mmHg that results in end-organ ischemia and requires countermeasures such as ultrafiltration reduction or saline infusion to increase blood pressure to improve patient's symptoms, is a known complication of hemodialysis and is associated with several potential adverse outcomes. Its pathogenesis is complex and involves both patient-related factors such as age and comorbidities, as well as factors related to the dialysis prescription itself. Key factors include the need for volume removal during hemodialysis and a suboptimal vascular response which compromises the ability to compensate for acute intravascular volume loss. Inadequate vascular refill, incorrect assessment or unaccounted changes of target weight, acute illnesses and medication interference are further potential contributors. Intradialytic hypotension can lead to compromised tissue perfusion and end-organ damage, both acutely and over time, resulting in repetitive injuries. To address these problems, a careful assessment of subjective symptoms, minimizing interdialytic weight gains, individualizing dialysis prescription and adjusting the dialysis procedure based on patients' risk factors can mitigate negative outcomes.

Patients with High Hematocrit Undergoing Coronary Artery Bypass Graft Surgery: A Case Report and Literature Review

Patients undergoing coronary artery bypass graft (CABG) surgery with elevated hematocrit levels can face unique challenges related to increased blood viscosity, compromised tissue perfusion, and impaired oxygen delivery. This case report presents a 45-year-old male patient with very high hematocrit levels who underwent CABG surgery. Preoperative optimization, intraoperative monitoring, and postoperative management were implemented to mitigate the risks associated with high hematocrit. The patient’s hematocrit, blood gases, and cerebral saturation were continuously monitored during the procedure, demonstrating adequate perfusion. The patient had an uneventful postoperative course and was extubated the same day. A literature review revealed limited evidence regarding the management of high hematocrit patients undergoing cardiac surgery, emphasizing the need for further research. Tailored management strategies, including preoperative hematocrit optimization and individualized antithrombotic therapy, are crucial for optimizing outcomes in this patient population.

Impact of a VA-ECMO in Combination with an Extracorporeal Cytokine Hemadsorption System in Critically Ill Patients with Cardiogenic Shock-Design and Rationale of the ECMOsorb Trial.

Cardiogenic shock and arrest present as critical, life-threatening emergencies characterized by severely compromised tissue perfusion and inadequate oxygen supply. Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) serves as a mechanical support system for patients suffering shock refractory to conventional resuscitation. Despite the utilization of VA-ECMO, clinical deterioration due to systemic inflammatory response syndrome (SIRS) resulting from the underlying shock and exposure of blood cells to the artificial surfaces of the ECMO circuit may occur. To address this issue, cytokine adsorbers offer a valuable solution by eliminating blood proteins, thereby controlling SIRS and potentially improving hemodynamics. Consequently, a prospective, randomized, blinded clinical trial will be carried out with ECMOsorb. ECMOsorb is a single-center, controlled, randomized, triple-blinded trial that will compare the hemodynamic effects of treatment with a VA-ECMO in combination with a cytokine adsorber (CytoSorb®, intervention) to treatment with VA-ECMO only (control) in patients with cardiogenic shock (with or without prior cardiopulmonary resuscitation (CPR)) requiring extracorporeal, hemodynamic support. Fifty-four patients will be randomized in a 1:1 fashion to the intervention or control group over a 36-month period. The primary endpoint of ECMOsorb is the improvement of the Inotropic Score (IS) 72 h after the intervention. Prognostic indicators, including mortality rates, hemodynamic parameters, laboratory findings, echocardiographic assessments, quality of life measurements, and clinical parameters, will serve as secondary outcome measures. The safety evaluation encompasses endpoints such as air embolisms, allergic reactions, peripheral ischemic complications, vascular complications, bleeding incidents, and stroke occurrences. The ECMOsorb trial seeks to assess the efficacy of a cytokine adsorber (CytoSorb®; CytoSorbents Europe GmbH, Berlin, Germany) in reducing SIRS and improving hemodynamics in patients with cardiogenic shock who are receiving VA-ECMO. We hypothesize that a reduction in cytokine levels can lead to faster weaning from inotropic and mechanical circulatory support, and ultimately to improved recovery.

AVOID; a phase III, randomised controlled trial using indocyanine green for the prevention of anastomotic leakage in colorectal surgery

IntroductionAnastomotic leakage (AL) is one of the major complications after colorectal surgery. Compromised tissue perfusion at the anastomosis site increases the risk of AL. Several cohort studies have shown that...

Fluid Therapy During Cardiopulmonary Resuscitation

Cardiopulmonary arrest (CPA), the acute cessation of blood flow and ventilation, is fatal if left untreated. Cardiopulmonary resuscitation (CPR) is targeted at restoring oxygen delivery to tissues to mitigate ischemic injury and to provide energy substrate to the tissues in order to achieve return of spontaneous circulation (ROSC). In addition to basic life support (BLS), targeted at replacing the mechanical aspects of circulation and ventilation, adjunctive advanced life support (ALS) interventions, such as intravenous fluid therapy, can improve the likelihood of ROSC depending on the specific characteristics of the patient. In hypovolemic patients with CPA, intravenous fluid boluses to improve preload and cardiac output are likely beneficial, and the use of hypertonic saline may confer additional neuroprotective effects. However, in euvolemic patients, isotonic or hypertonic crystalloid boluses may be detrimental due to decreased tissue blood flow caused by compromised tissue perfusion pressures. Synthetic colloids have not been shown to be beneficial in patients in CPA, and given their documented potential for harm, they are not recommended. Patients with documented electrolyte abnormalities such as hypokalemia or hyperkalemia benefit from therapy targeted at those disturbances, and patients with CPA induced by lipid soluble toxins may benefit from intravenous lipid emulsion therapy. Patients with prolonged CPA that have developed significant acidemia may benefit from intravenous buffer therapy, but patients with acute CPA may be harmed by buffers. In general, ALS fluid therapies should be used only if specific indications are present in the individual patient.

Optimizing quantitative fluorescence angiography for visceral perfusion assessment.

Compromised tissue perfusion is a significant risk factor for anastomotic leakage after intestinal resection, leading to prolonged hospitalization, risk of recurrence after oncologic resection, and reduced survival. Thus, a tool reducing the risk of leakage is highly warranted. Quantitative indocyanine green angiography (Q-ICG) is a new method that provides surgeons with an objective evaluation of tissue perfusion. In this systematic review, we aimed to determine the optimal methodology for performing Q-ICG. A comprehensive search of the literature was performed following the PRISMA guidelines. The following databases were searched: PubMed, Embase, Scopus, and Cochrane. We included all clinical studies that performed Q-ICG to assess visceral perfusion during gastrointestinal surgery. Bias assessment was performed with the Newcastle Ottawa Scale. A total of 1216 studies were screened, and finally, 13 studies were included. The studies found that intensity parameters (maximum intensity and relative maximum intensity) could not identify patients with anastomotic leakage. In contrast, the inflow parameters (time-to-peak, slope, and t1/2max) were significantly associated with anastomotic leakage. Only two studies performed intraoperative Q-ICG while the rest performed Q-ICG retrospectively based on video recordings. Studies were heterogeneous in design, Q-ICG parameters, and patient populations. No randomized studies were found, and the level of evidence was generally found to be low to moderate. The results, while heterogenous, all seem to point in the same direction. Fluorescence intensity parameters are unstable and do not reflect clinical endpoints. Instead, inflow parameters are resilient in a clinical setting and superior at reflecting clinical endpoints.

Evaluation of Lung Quality by Near-Infrared Fluorescent Imaging during Ex Vivo Lung Perfusion

Improved real-time assessment of donor lung quality during Ex Vivo Lung Perfusion (EVLP) could enhance safe utilization of lungs for transplantation. Near-infrared (NIR) fluorescent imaging with indocyanine green (ICG) has been used in various clinical intraoperative applications to evaluate tissue perfusion. We investigated the feasibility of NIR imaging during EVLP and aimed to detect and quantify lung perfusion and permeability. Pig lungs with extended 24-hour cold ischemia (n=4) and human lungs rejected from clinical transplantation (n=2) were assessed with NIR imaging during EVLP. Serial NIR imaging was performed with SPY Elite imaging system after ICG (0.3, 0.6 or 1.0 mg) administration through pulmonary artery (Fig A). Tissue perfusion was quantified using SPYQ analysis software, and tissue ICG accumulation was correlated with lung damage. Strong NIR signal was detected immediately after ICG administration with 0.6 mg (pig lungs) or 1.0 mg (human lungs) doses resulting in optimal fluorescence for tissue perfusion evaluation. In contrast to the transient kinetics and fast liver metabolism during clinical in vivo ICG administration, a single ICG dose during EVLP resulted in stable NIR signal for over 10 hours. Perfusion quantification of pig lungs with extended cold preservation revealed peripheral areas with compromised tissue perfusion that gradually recovered over time with recruitment of additional pulmonary vascular beds (Fig B). ICG accumulation was detected in sites with damage and increased vascular permeability in pig and human lungs (Fig C and D). NIR imaging with a clinically-approved intravascularly-delivered ICG fluorescent probe can dynamically quantify tissue perfusion and detect damage-induced vascular permeability. This novel and promising imaging modality could be used during EVLP to assess lung quality, or to determine effects of therapeutics that target tissue perfusion and vascular permeability.

Erythrocyte deformability in children with autism spectrum disorder: correlation with clinical features.

Biomechanical properties of erythrocytes play an important role in health and disease. Deformability represents intrinsic property of erythrocytes to undergo deformation that is crucial for their passage through the narrow capillaries. The erythrocyte damage can lead to compromised tissue perfusion and consequently play a role in the pathogenesis of various diseases including neurological ones. Data available in databases indicate that erythrocytes in autism spectrum disorder (ASD) are altered. This may affect the clinical symptoms of ASD. The aim of our study was to determine erythrocyte deformability in 54 children with ASD and correlate it with clinical symptoms. We found significant negative correlation between erythrocyte deformability and score in C domain of the Autism Diagnostic Interview-Revised (ADI-R) diagnostic tool describing the measure of restrictive, repetitive, and stereotyped behaviors and interests, mainly observable in C1 and C2, but not in C3 and C4 subdomains. This supports the findings of other authors and suggest that behavioral domain C comprises of more subcategories with different underlying etiology. Our results also indicate that abnormalities in erythrocyte deformability may be involved in ASD pathomechanisms and contribute to its clinical manifestation. Further research is necessary to bring more data and identify erythrocyte deformability as prognostic biomarker in ASD.

The Impact of Extracorporeal Shock Wave Therapy on Microcirculation in Diabetic Feet: A Pilot Study.

Patients with diabetic foot commonly experience vascular insufficiency and compromised tissue perfusion. Extracorporeal shockwave therapy (ESWT) reportedly promotes wound healing and angiogenesis, but clinical studies on the effect of ESWT on angiogenesis are scarce and the exact mechanism remains unclear. To investigate the effect of ESWT on cutaneous microcirculation in diabetic feet. Ten patients with diabetic feet received ESWT twice weekly for a total of six sessions. Transcutaneous partial oxygen pressure (TcPO2) and cutaneous blood flow were measured before and after ESWT. The treated feet showed statistically significant improvements in the mean TcPO2 (P < .01) and cutaneous blood flow level (P < .05) compared with control feet. In treated feet, TcPO2 increased by 19.6%, from 41.4 ± 9.9 to 49.5 ± 8.7 mm Hg (P < .05). In control feet, TcPO2 decreased by 11.6%, from 39.5 ± 14.0 to 34.9 ± 14.5 mm Hg (P = .059). The average cutaneous blood flow level of treated feet before ESWT was 36.9 ± 25.6, which increased to 48.3 ± 32.4 AU after ESWT (30.9% increase; P = .646). In control feet, the cutaneous blood flow level decreased from 80.5 ± 36.7 to 60.4 ± 38.8 AU, a decrease of 25.0% (P = .241). These results demonstrate that ESWT may have beneficial effects on microcirculation in diabetic feet.

Possibility of Injecting Adipose-Derived Stromal Vascular Fraction Cells to Accelerate Microcirculation in Ischemic Diabetic Feet: A Pilot Study.

Background and ObjectivesBeneficial effects of human adipose-derived stromal vascular fraction (SVF) cell injection on microcirculation have been recently reported in in vitro and in vivo studies. However, no clinical studies have reported its effect in diabetic patients who commonly experience compromised tissue perfusion, regardless of the status of intravascular blood flow. The present piloting study was designed to clinically examine the possibility of SVF cell injection to accelerate microcirculation, particularly in ischemic diabetic feet.MethodsTen diabetic feet were included to receive subcutaneous injection of SVF cells around wounds. Transcutaneous partial oxygen pressure (TcPO2) and cutaneous microvascular blood flow were measured before and every four weeks after cell injection until the 12th week visit.ResultsTcPO2 values increased from 31.3±7.4 before injection to 46.4±8.2 mmHg at 12 weeks after SVF injection (1.5-fold, p<0.05). Cutaneous microvascular blood flow levels increased from 34.0±21.1 before injection to 76.1±32.5 perfusion unit at 12 weeks after SVF injection (2.2-fold, p<0.05). There were no adverse events related to SVF cell injection.ConclusionsResults of this study demonstrate that adipose-derived SVF cell injection have the possibility to provide beneficial effects on microcirculation in ischemic diabetic feet.

Renal and extrarenal effects of fibroblast growth factor 23

Fibroblast growth factor 23 (FGF23) is a hormone with a central role in the regulation of phosphate homeostasis. This regulation is accomplished by the coordinated modulation of renal phosphate handling, vitamin D metabolism and parathyroid hormone secretion. Patients with kidney disease have increased circulating levels of FGF23 and in other patient populations and in healthy individuals, FGF23 levels also rise following an increase in dietary phosphate intake. Maladaptive increases in FGF23 have a detrimental effect on several organs and tissues and, importantly, these pathological changes most likely contribute to increased morbidity and mortality. For example, in the context of heart disease, FGF23 is involved in the development of pathological hypertrophy that can lead to congestive heart failure. Increased FGF23 concentrations can also lead to microcirculatory changes, in particular reduced vasodilatory capacity, and collectively these cardiovascular changes can compromise tissue perfusion. In addition, FGF23 is associated with inflammation and an increased risk of infection; other potentially detrimental effects of FGF23 are likely to emerge in the future. Most importantly, recent insights demonstrate that FGF23 can be therapeutically targeted, which holds promise for the treatment of many patients in a variety of clinical settings.

In vitro development and in vivo application of a platinum-based electrochemical device for continuous measurements of peripheral tissue oxygen

Acute limb ischaemia is caused by compromised tissue perfusion and requires immediate attention to reduce the occurrence of secondary complications that could lead to amputation or death. To address this, we have developed a novel platinum (Pt)-based electrochemical oxygen (O2) device for future applications in clinical monitoring of peripheral tissue ischaemia. The effect of integrating a Pt pseudo-reference electrode into the O2 device was investigated in vitro with an optimum reduction potential of −0.80V. A non-significant (p=0.11) decrease in sensitivity was recorded when compared against an established Pt-based O2 sensor operating at −0.65V. Furthermore, a biocompatible clinical sensor (ClinOX) was designed, demonstrating excellent linearity (R2=0.99) and sensitivity (1.41±0.02nAμM−1) for O2 detection. Significant rapid decreases in the O2 current during in vivo ischaemic insults in rodent limbs were reported for Pt-Pt (p<0.001) and ClinOX (p<0.01) and for ClinOX (p<0.001) in porcine limbs. Ex vivo sensocompatibility investigations identified no significant difference (p=0.08) in sensitivity values over 14days of exposure to tissue homogenate. The Pt-Pt based O2 design demonstrated high sensitivity for tissue ischaemia detection and thus warrants future clinical investigation.

Minimizing osteoradionecrosis after mandibular reconstruction and radiation in advanced head and neck cancer patients.

Osteoradionecrosis may develop on the residual mandible or reconstructed fibula because of inadequate soft tissue coverage and compromised tissue perfusion post mandibular reconstruction, and radiation. This study was to investigate the incidence of osteoradionecrosis following class III mandibular defect reconstructions with an OPAC flap versus a fibula OSC flap. A retrospective review of a consecutive series of mandibular reconstructions between 1999 and 2010 was performed. Mandibular defects and corresponding flap types were analyzed with emphasis on outcome, complications, and rates of osteoradionecrosis among the two subgroups. A total of 121 fibula flaps were performed, consisting of 53 OPAC and 68 fibula OSC flaps. Complications trended higher for OPAC flaps in partial and total flap loss rates as well as venous congestion when compared with the OSC flap cohort. The OPAC group had statistically significant lower rates of osteoradionecrosis and plate exposure than the OSC group (P = 0.04). The OPAC flap may be preferable to fibula OSC flap in mandibular reconstruction given its lower rates of osteoradionecrosis and plate exposure. This flap type may be the flap of choice for class III defects where additional vascularized tissue may be critical for addressing significant soft tissue deficiency. J. Surg. Oncol. 2016;114:399-404. © 2016 Wiley Periodicals, Inc.

Bright and dark vessels on stroke imaging: different sides of the same coin?

Prominent hypointense cerebral vessels on susceptibility-weighted imaging (SWI) and the hyperintense vessel sign (HVS) on fluid-attenuated inversion recovery (FLAIR) imaging are considered as markers of compromised tissue perfusion in cerebral ischemia. In this study, we aimed to identify the correlation between HVS on FLAIR and hypointense vessels on SWI, and to determine whether these imaging features provide independent prognostic information in patients with ischemic stroke. We retrospectively analyzed consecutive ischemic stroke patients with proximal middle cerebral artery (MCA) occlusion who underwent SWI and FLAIR within 24 h of symptom onset. The presence of hypointense vessels on SWI and hyperintense vessels on FLAIR in >4 of 10 slices encompassing the MCA territory were considered to represent prominent hypoperfusion. Among 50 patients, 62% had a prominent HVS on FLAIR and 68% had prominent hypointense vessels on SWI. There was a moderate but significant correlation between the number of slices with HVS on FLAIR and prominent hypointense vessels on SWI (r=0.425, P = 0.002). In multivariate analyses, the prominence of hypointense vessels on SWI, but not HVS on FLAIR, was significantly associated with a higher discharge NIHSS score (P = 0.027), mRS score (P = 0.021), and lesion growth (P = 0.050). The significant, albeit moderate, correlation between markers of compromised tissue perfusion on FLAIR and SWI suggests that these imaging features reflect different but interrelated aspects of cerebral hemodynamics during ischemic stroke. Our findings highlight that while HVS on FLAIR denotes the presence of leptomeningeal collaterals, hypointense vessels on SWI signify the sufficiency of cerebral blood flow at the tissue level and are therefore more critical in terms of prognosis.

A study of management of fracture proximal tibia by different modalities

In the 1990s, Krettek et al. popularized Minimally Invasive Percutaneous Plate Osteosynthesis Techniques using conventional implants placed through small incisions and submuscular (subcutaneous) tunnels. Cadaveric studies demonstrated better preservation of periosteal vasculature with these minimally invasive methods than with standard open exposures for internal fixation. As part of the continued development of Biologically Friendly Plating, and to facilitate Minimally Invasive Plating Techniques, the use of plates that allow screws to lock into the plate to create a fixed angle construct is gaining popularity nowadays. Several different surgical approaches have been described for Proximal Tibial fractures (medial, lateral and combined) depending on the location of the fracture. Combined extensive approaches, in particular, are associated with high complication rates, possibly due to compromised soft tissue perfusion and/or extensive soft tissue stripping from bone fragments. A review of the recent literature demonstrates a trend toward increasingly limited open reduction and internal fixation, often in association with some form of external stabilization. Minimally invasive techniques have also been described for intra-articular fractures (metaphyseal and diaphyseo-metaphyseal) of the proximal tibia. These techniques avoid the long incisions and extensive soft tissue stripping associated with conventional techniques and are best used with shorter, lower profile plates.

Bedside ABG, electrolytes, lactate and procalcitonin in emergency pediatrics

Point of care testing, is the term commonly applied to the bedside tests performed in sick patients. Common clinical conditions encountered in pediatric emergency rooms are respiratory, gastro-intestinal, infections and cardiac. Emergencies at most of the places, especially developing countries are overburdened. Availability of tests like arterial blood gas, lactate, electrolytes and procalcitonin, bedside tests or point of care tests can help identify sick patients quickly. Abnormalities like acid-base disturbances and dyselectrolytemias can be dealt with instantly, thus improving the overall prognosis. Lactate levels in emergency give the earliest clue to cardiovascular compromise and poor tissue perfusion. Procalcitonin has recently gained significant importance as an acute phase reactant for early identification of sepsis. Decisions for initiating or withholding antibiotic therapy can also be taken based on procalcitonin levels in emergency. Bedside estimation of serum electrolytes, blood gas analysis and procalcitonin thus facilitate the clinical evaluation and management of critical patients. An extensive literature review of current status of these investigations as point of care tests is appraised here.

The use of regional cerebral oximetry monitoring during controlled hypotension: a case series

Regional cerebral oximetry monitoring was used to guide nitroglycerin infusion and IV fluid administration during controlled hypotension in order to optimize each individual patient's mean arterial pressure in a series of 20 consecutive patients who underwent major open urological or abdominal surgery. Although controlled hypotension offers a definite benefit in patients undergoing complex surgery where blood loss will be elevated or would severely compromise the surgical field, it is not without risk as low arterial pressure may compromise tissue perfusion and promote ischemia. In this case series, despite an average mean arterial pressure decrease of 19.5 % (p < 0.001), cerebral oximetry values increased by an average of 22.7 % (p < 0.001) after the nitroglycerin infusion had been initiated (220 mcg/min average). Patients received an average of 3.15L crystalloid and 437 ml albumin in fluid resuscitation.