Sublingual microcirculation in healthy pediatric population using the sidestream dark-field imaging method.

BACKGROUND: The sidestream dark-field imaging method is used to study microcirculation. Normal values of sublingual microcirculation parameters in healthy children of different age and gender categories are unknown. OBJECTIVE: The study's main goal was to determine normal values of selected parameters of sublingual microcirculation in healthy children of different age and gender categories. METHODS: 40 healthy children were measured, ten aged 3-5.9 years, ten aged 6-10.9 years, ten aged 11-14.9 years, and ten aged 15-18.9 years. After recording the basic anthropometric parameters and vital functions, each volunteer had their microcirculation measured using an SDF probe placed sublingually. Three video clips were recorded and processed offline, and the three best and most stable parts of each were analyzed. RESULTS: Total vascular density, small vessel density, proportion of perfused small vessels, perfused vessel density, perfused small vessel density, and DeBacker's score were significantly higher in females than in males. There were no differences between age groups in microcirculation parameters except MFI. CONCLUSIONS: Age does not influence normal values of microcirculatory parameters. Female gender was associated with higher vessel density, perfused vessel density, and DeBacker's score. A suggestion of the normal range of microcirculatory parameters in healthy children is provided.

Practical Aspects of Esophageal Pressure Monitoring in Patients with Acute Respiratory Distress Syndrome.

Esophageal pressure (Pes) monitoring is a minimally invasive advanced respiratory monitoring method with the potential to guide ventilation support management. Pes monitoring enables the separation of lung and chest wall mechanics and estimation of transpulmonary pressure, which is recognized as an important risk factor for lung injury during both spontaneous breathing and mechanical ventilation. Appropriate balloon positioning, calibration, and measurement techniques are important to avoid inaccurate results. Both the approach of using absolute expiratory Pes values and the approach based on tidal Pes difference have shown promising results for ventilation adjustments, with the potential to decrease the risk of ventilator-induced lung injury.

The Impact of Individualized Hemodynamic Management on Intraoperative Fluid Balance and Hemodynamic Interventions during Spine Surgery in the Prone Position: A Prospective Randomized Trial.

Background and Objectives: The effect of individualized hemodynamic management on the intraoperative use of fluids and other hemodynamic interventions in patients undergoing spinal surgery in the prone position is controversial. This study aimed to evaluate how the use of individualized hemodynamic management based on extended continuous non-invasive hemodynamic monitoring modifies intraoperative hemodynamic interventions compared to conventional hemodynamic monitoring with intermittent non-invasive blood pressure measurements. Methods: Fifty adult patients (American Society of Anesthesiologists physical status I−III) who underwent spinal procedures in the prone position and were then managed with a restrictive fluid strategy were prospectively randomized into intervention and control groups. In the intervention group, individualized hemodynamic management followed a goal-directed protocol based on continuously non-invasively measured blood pressure, heart rate, cardiac output, systemic vascular resistance, and stroke volume variation. In the control group, patients were monitored using intermittent non-invasive blood pressure monitoring, and the choice of hemodynamic intervention was left to the discretion of the attending anesthesiologist. Results: In the intervention group, more hypotensive episodes (3 (2−4) vs. 1 (0−2), p = 0.0001), higher intraoperative dose of ephedrine (0 (0−10) vs. 0 (0−0) mg, p = 0.0008), and more positive fluid balance (680 (510−937) vs. 270 (196−377) ml, p < 0.0001) were recorded. Intraoperative norepinephrine dose and postoperative outcomes did not differ between the groups. Conclusions: Individualized hemodynamic management based on data from extended non-invasive hemodynamic monitoring significantly modified intraoperative hemodynamic management and was associated with a higher number of hemodynamic interventions and a more positive fluid balance.

Surgical Pleth Index and Analgesia Nociception Index for intraoperative analgesia in patients undergoing neurosurgical spinal procedures: a comparative randomized study.

BACKGROUND: The Surgical Plethysmographic Index (SPI) and the Analgesia Nociception Index (ANI) have been suggested for the non-invasive intraoperative monitoring of nociception/anti-nociception balance. We aimed to compare patterns of intraoperative use of opioids, postoperative cortisol levels and postoperative pain scores after intraoperative analgesia guided either by ANI, SPI or anesthesiologist's judgment. METHODS: Seventy-two adult ASA I-III patients scheduled for elective neurosurgical spinal procedures were randomized into the ANI group, SPI group and control group. Anesthesia and intraoperative use of opioids (sufentanil boluses based on body weight) were managed according to a strict protocol. The use of sufentanil was targeted to keep ANI value 50-70 in the ANI group, SPI value below individual postinduction baseline value plus 10 points in the SPI group. In the control group, the use of opioids was left at anesthesiologist's discretion. RESULTS: Additional sufentanil boluses were administered earlier in the ANI and SPI groups in comparison to the control group (third dose after 51.8±22.1 vs. 52.7±14.8 vs. 84.5±24.8 min respectively, P=0.001; fourth dose after 61.3±30.1 vs. 57.2±14.1 vs. 120.0±26.2 min, P=0.003, and fifth dose after 78.8±33.7 vs. 74.0±11.6 vs. 146.7±23.2 min respectively, P=0.009). There were no differences in postoperative cortisol levels, time to spontaneous breathing at the end of anesthesia and postoperative pain scores. CONCLUSIONS: Both ANI and SPI guidance significantly modified intraoperative opioid use, but no modification of postoperative cortisol levels and postoperative pain was observed.

Acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) is a type of acute diffuse lung injury associated with a predisposing risk factor, characterized by inflammation leading to increased pulmonary vascular permeability and loss of aerated lung tissue. The hallmarks of the clinical syndrome are hypoxemia and bilateral radiographic opacities, associated with several physiological derangements including: increased pulmonary venous admixture, increased physiological dead space, and decreased respiratory system compliance. No pharmacologic treatments aimed at the underlying pathology have been shown to be effective, and the management remains supportive. Lung-protective mechanical ventilation remains the key supportive intervention in ARDS patients, although extracorporeal lung support may extend its role in the near future.

The Effect of Fluid Loading and Hypertonic Saline Solution on Cortical Cerebral Microcirculation and Glycocalyx Integrity.

BACKGROUND: Fluid loading and hyperosmolar solutions can modify the cortical brain microcirculation and the endothelial glycocalyx (EG). This study compared the short-term effects of liberal fluid loading with a restrictive fluid intake followed by osmotherapy with hypertonic saline (HTS) on cerebral cortical microcirculation and EG integrity in a rabbit craniotomy model. METHODS: The experimental rabbits were allocated randomly to receive either <2 mL/kg/h (group R, n=14) or 30 mL/kg/h (group L, n=14) of balanced isotonic fluids for 1 hour. Then, the animals were randomized to receive 5 mL/kg intravenous infusion of either 3.2% saline (group HTS, n=14) or 0.9% saline (group normal saline, n=13) in a 20-minute infusion. Microcirculation in the cerebral cortex based on sidestream dark-field imaging, a morphologic index of glycocalyx damage to sublingual and cortical brain microcirculation (the perfused boundary region), and serum syndecan-1 levels were evaluated. RESULTS: Lower cortical brain perfused small vessel density (P=0.0178), perfused vessel density (P=0.0286), and total vessel density (P=0.0447) were observed in group L, compared with group R. No differences were observed between the HTS and normal saline groups after osmotherapy. Cerebral perfused boundary region values (P=0.0692) and hematocrit-corrected serum syndecan-1 levels (P=0.0324) tended to be higher in group L than in group R animals. CONCLUSIONS: Liberal fluid loading was associated with altered cortical cerebral microcirculation and EG integrity parameters. The 3.2% saline treatment did not affect cortical cerebral microcirculation or EG integrity markers.

Effect of acute hypernatremia induced by hypertonic saline administration on endothelial glycocalyx in rabbits.

BACKGROUND AND OBJECTIVE: The endothelial glycocalyx (EG) is fragile and sensitive to damage such as exposure to hypernatremia. Our aim was to describe the influence of hypernatremia on the EG in sublingual and brain microcirculation in rabbits. METHODS: Hypernatremia was induced by intravenous administration of 10% NaCl solution. The sublingual and brain microcirculation were evaluated by the Side-stream Dark Field imaging before (T1) and 20 minutes after infusion of 10% saline (T2). Damage to the EG was quantified by automated analysis of Perfused Boundary Region (PBR) indicating the amount of penetration of red blood cells into the EG. Syndecan-1 levels were also measured. RESULTS: Hypernatremia was reached in all 20 animals, the PBR values of the sublingual area raised from 1,98 (0,3) to 2,17 (0,18) µm (p = 0,05). The levels of syndecan-1 (1,23 (0,36); 1,31 (0,33) ng/l, p = 0,3) did not mirror PBR changes. CONCLUSIONS: Hypernatremia increased the PBR within the sublingual microcirculation in our animal model, probably due to compression of the EG related to temporary intravascular hypervolemia and changes of the EG charge in RBC instead of direct damaging effect on EG, which has been excluded by rather unchanged levels of syndecan-1.

Effects of Hypertonic Saline and Sodium Lactate on Cortical Cerebral Microcirculation and Brain Tissue Oxygenation.

BACKGROUND: Hyperosmolar solutions have been used in neurosurgery to modify brain bulk. The aim of this animal study was to compare the short-term effects of equivolemic, equiosmolar solutions of hypertonic saline (HTS) and sodium lactate (HTL) on cerebral cortical microcirculation and brain tissue oxygenation in a rabbit craniotomy model. METHODS: Rabbits (weight, 1.5 to 2.0 kg) were anesthetized, ventilated mechanically, and subjected to a craniotomy. The animals were allocated randomly to receive a 3.75 mL/kg intravenous infusion of either 3.2% HTS (group HTS, n=9), half-molar sodium lactate (group HTL, n=10), or normal saline (group C, n=9). Brain tissue partial pressure of oxygen (PbtO2) and microcirculation in the cerebral cortex using sidestream dark-field imaging were evaluated before, 20 and 40 minutes after 15 minutes of hyperosmolar solution infusion. Global hemodynamic data were recorded, and blood samples for laboratory analysis were obtained at the time of sidestream dark-field image recording. RESULTS: No differences in the microcirculatory parameters were observed between the groups before and after the use of osmotherapy. Brain tissue oxygen deteriorated over time in groups C and HTL, this deterioration was not significant in the group HTS. CONCLUSIONS: Our findings suggest that equivolemic, equiosmolar HTS and HTL solutions equally preserve perfusion of cortical brain microcirculation in a rabbit craniotomy model. The use of HTS was better in preventing the worsening of brain tissue oxygen tension.

Effects of hypertonic saline and mannitol on cortical cerebral microcirculation in a rabbit craniotomy model.

BACKGROUND: Hyperosmolar solutions have been used in neurosurgery to modify brain bulk and prevent neurological deterioration. The aim of this animal study was to compare the short-term effects of equivolemic, equiosmolar solutions of mannitol and hypertonic saline (HTS) on cerebral cortical microcirculation in a rabbit craniotomy model. METHODS: Rabbits (weight, 2.0-3.0 kg) were anesthetized, ventilated mechanically, and subjected to a craniotomy. The animals were allocated randomly to receive a 3.75 ml/kg intravenous infusion of either 3.2% HTS (group HTS, n = 8) or 20% mannitol (group MTL, n = 8). Microcirculation in the cerebral cortex was evaluated using sidestream dark-field (SDF) imaging before and 20 min after the end of the 15-min HTS infusion. Global hemodynamic data were recorded, and blood samples for laboratory analysis were obtained at the time of SDF image recording. RESULTS: No differences in the microcirculatory parameters were observed between the groups before the use of osmotherapy. After osmotherapy, lower proportions of perfused small vessel density (P = 0.0474), perfused vessel density (P = 0.0457), and microvascular flow index (P = 0.0207) were observed in the MTL group compared with those in the HTS group. CONCLUSIONS: Our findings suggest that an equivolemic, equiosmolar HTS solution better preserves perfusion of cortical brain microcirculation compared to MTL in a rabbit craniotomy model.

A comparison of equivolume, equiosmolar solutions of hypertonic saline and mannitol for brain relaxation in patients undergoing elective intracranial tumor surgery: a randomized clinical trial.

BACKGROUND: Hyperosmolar solutions have been used in neurosurgery to modify brain bulk and prevent neurological deterioration. The purpose of the study was to compare the effects of equivolume, equiosmolar solutions of mannitol and hypertonic saline (HTS) on brain relaxation and postoperative complications in patients undergoing elective intracranial tumor surgery. METHODS: In this prospective, randomized study, patients with American Society of Anesthesiologists physical status I to III scheduled to undergo a craniotomy for intracranial tumors were enrolled. Patients received a 3.75 mL/kg intravenous infusion of either 3.2% HTS (group HTS, n=36) or 20% mannitol (group M, n=38). The surgeon assessed the condition of the brain using a 4-point scale after opening the dura. Recorded measures included duration of surgery, blood loss, urine output, volume and type of infused fluids, hemodynamic variables, electrolytes, glucose, creatinine, predefined postoperative complications, and length of intensive care unit and hospital stays. RESULTS: Brain relaxation conditions in group HTS (score 1/2/3/4, n=10/17/2/7) were better than those in group M (score 1/2/3/4, n=3/18/3/14, P=0.0281). Patients in group M had higher urine output, received more crystalloids during surgery, and displayed lower central venous pressure and lower natremia at the end of surgery than did patients in group HTS. No significant differences in postoperative complications or lengths of intensive care unit and hospital stays were observed between the groups. CONCLUSIONS: Our results suggest that HTS provides better brain relaxation than mannitol during elective intracranial tumor surgery.