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Background: The purpose of this study was to assess the prevalence of coma among patients in critical care units in Chile. We also aimed to provide insight into the demographic characteristics, etiologies, and complications associated with coma., Methods: A single day cross-sectional study was conducted through a national survey of public and private hospitals with critical and intensive cardiac care units across Chile. Data were collected using an online questionnaire that contained questions regarding critically ill patients' information, demographic characteristics, etiology and duration of coma, medical complications, and support requirements., Results: A total of 84% of all health facilities answered, accounting for a total of 2,708 patients. The overall coma prevalence was 2.9%. The median age of the comatose patients was 61 years (interquartile range 50-72) and 66.2% were male. The median coma duration was five days (interquartile range 2-9). Cerebral hemorrhage was the most common etiology, followed by severe hypoxic-ischemic encephalopathy, acute ischemic stroke, and traumatic brain injury. A total of 48.1% of coma patients experienced acute and ongoing treatment complications, with pneumonia being the most common complication, and 97.4% required support during comatose management., Conclusions: This study provides an overview of the prevalence of coma in Chilean critical and cardiac care units. Coma is a common condition. Comatose patients frequently experience medical complications during their hospitalization., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature and Neurocritical Care Society.)

Introduction: Critically ill patients undergoing extracorporeal membrane oxygenation (ECMO) exhibit unique pharmacokinetics. This study aimed to assess the achievement of vancomycin therapeutic targets in these patients. Methods: This retrospective cohort study included patients on ECMO treated with vancomycin between January 2010 and December 2018. Ninety patients were analyzed based on ECMO connection modality, baseline creatinine levels, estimated glomerular filtration rate (eGFR), renal replacement therapy (RRT) requirements, and vancomycin loading dose administration. Results: Twenty-three percent of the patients achieved the therapeutic range defined by baseline levels. No significant differences in meeting the therapeutic goal were found in multivariate analysis considering ECMO cannulation modality, initial creatinine level, initial eGFR, RRT requirement, or loading dose use. All trough levels between 15 and 20 mcg/mL achieved an estimated area under the curve/minimum inhibitory concentration (AUC/MIC) between 400 and 600, almost all trough levels over 10 mcg/mL predicted an AUC/MIC >400. Discussion: Achieving therapeutic plasma levels in these patients remains challenging, potentially due to factors such as individual pharmacokinetics and pathophysiology. A trough plasma level between 12 and 20 estimated the therapeutic AUC/MIC for all models, proposing a possible lower target, maintaining exposure, and potentially avoiding adverse effects. Despite being one of the largest cohorts of vancomycin use in ECMO patients studied, its retrospective nature and single-center focus limits its broad applicability.

Background: Osmotic demyelination syndrome (ODS) with cerebral cortical involvement is a rare complication of severe hyponatremia correction. Careful management of hyponatremia is crucial, particularly in patients with risk factors, such as alcohol use disorder and diabetes insipidus., Case: A patient in his 40s with a history of alcohol use disorder and central diabetes insipidus developed ODS after a 24 mEq/L osmolar increase during the treatment of hyponatremia. The patient's condition progressed into locked-in syndrome and then improved to spastic tetraparesis after cortical basal ganglia ODS improved., Discussion: The differential diagnosis of cortical demyelination includes laminar cortical necrosis, being the interpretation of Apparent Diffusion Coefficient (ADC) MRI sequence is a useful tool.This case underscores the need to investigate and improve diagnosis and treatment strategies in patients with ODS. It also emphasises the significance of careful hyponatremia correction and frequent monitoring, particularly in patients with known risk factors for ODS., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Early identification of vasospasm prior to symptom onset would allow prevention of delayed cerebral ischemia (DCI) in aneurysmal subarachnoid hemorrhage (aSAH). Dynamic cerebral autoregulation (DCA) is a noninvasive means of assessing cerebral blood flow regulation by determining independence of low-frequency temporal oscillations of systemic blood pressure (BP) and cerebral blood flow velocities (CBFV)., Methods: Eight SAH patients underwent prospectively a median of 7 DCA assessments consisting of continuous measurements of BCFV and BP. Transfer function analysis was applied to calculate average phase shift (PS) in low (0.07-0.2 Hz) frequency range for each hemisphere as continuous measure of DCA. Lower PS indicated poorer regulatory response. DCI was defined as a 2-point decrease in Glasgow Coma Score and/or infarction on CT., Results: Three subjects developed symptomatic vasospasm with median time-to-DCI of 9 days. DCI was significantly associated with lower PS over the entire recording period (Wald = 4.28; p = 0.039). Additionally, there was a significant change in PS over different recording periods after adjusting for DCI (Wald = 15.66; p = 0.001); particularly, a significantly lower mean PS day 3-5 after bleed (14.22 vs 27.51; p = 0.05)., Conclusions: DCA might be useful for early detection of symptomatic vasospasm. A larger cohort study of SAH patients is currently underway.

We report a 39-year-old male with an aneurysmal subarachnoid hemorrhage without hydrocephalus, in whom a right choroidal aneurysm was early excluded by endovascular coil insertion. Intracranial pressure (PIC) and cerebral oxygenation (PtiO2) sensors for neuromonitoring were installed due to a persistent comatose state. From the 3rd day, neuromonitoring became altered. CT angiography and cerebral angiography showed severe proximal and distal vasospasm (VE) of the middle (ACM) and anterior (ACA) right cerebral arteries. VE was treated with angioplasty and intravenous nimodipine. Forty eight hours later, despite hemodynamic maximization, neuromonitoring became altered again, mainly explained by a decrease in PtiO2 below 15 mmHg. A severe VE in ACM and right ACA was confirmed by angiography. Given the presence of an early and recurrent VE, which was associated with a decrease in cerebral oxygenation, internal carotid micro-catheters for continuous nimodipine infusion were installed. This therapy maintained a normal neuromonitoring for 15 days. During this period, attempts were done to decrease or discontinue the infusion, but the patient presented parallel falls of cerebral oxygenation or decreased cerebral perfusion observed with perfusion CT, interpreted as persistent VE. Finally, the infusion was stopped at day 15 without significant complication. We conclude that intra-arterial nimodipine continuous infusion in refractory VE can be useful and safe in selected patients. Multimodal neuromonitoring is essential.

Purpose: To determine the intra- and interrater agreement of mean flow velocity (MFV) and pulsatility index (PI) measurement in middle cerebral arteries, assessed by transcranial Doppler (TCD) with M-mode., Methods: Masked experienced neurosonologists performed TCD with M-mode using handheld probe in healthy adult volunteers. The Bland-Altman method for concordance and intraclass correlation coefficient were used., Results: Seventy-seven healthy volunteers and seven raters participated (3 on regular TCD shift and 4 off-shift). The intrarater absolute mean difference between measurements was 5.5 cm/s [95% confidence interval (CI), 4.7-6.3] for MVF and 0.073 (95% CI, 0.063-0.083) for PI. The difference between MFV measurements was significantly higher in off-shift raters ( p = 0.015). The interrater absolute mean difference between measurements was 6.5 cm/s (95% CI, 5.5-7.5) for MVF and 0.065 (95% CI, 0.059-0.071) for PI. No influence was found for the middle cerebral artery side, volunteer's sex, or age, and there was no significant difference between raters. The intraclass correlation coefficient was 82.2% (95% CI 77.8-85.6) and 72.9% (95% CI 67.4-77.6) for MFV and PI, respectively., Conclusions: There exists good intra- and interrater agreement in MFV and PI measurements using M-mode TCD. These results support the use of this noninvasive tool and are important for clinical and investigational purposes., Competing Interests: Conflicts of interest: PMV, AMB, JG, SI, JL, AR, and PML performed TCD in their regular clinical practice, and it is included in their salary. VVO, PB, FG, and GC declare no conflicts of interest.

Background: Temperature management using endovascular catheters is an established therapy in neurointensive care. Nonetheless, several case series have reported a high rate of thrombosis related to the use of endovascular hypothermia catheters., Methods: As a result of a pulmonary embolism that developed in a patient after removing an inferior vena cava hypothermia catheter, we designed a clinical protocol for managing and removing these devices. First, an invasive cavography was performed before the removal of the catheter. If there was a thrombus, a cava vein filter was inserted through jugular access. After that, the catheter was removed., Results: The venography found inferior vena cava thrombi in 18 of 20 consecutive patients. A concomitant ultrasonography study showed vena cava thrombosis in only three patients. A vena cava filter was inserted in all patients where thrombi were found, without any significant complication. Anticoagulation was started in all patients. No symptomatic pulmonary embolism was diagnosed until the time of discharge., Conclusions: The frequency of thrombosis related to temperature management catheters is extremely high (90 %). Furthermore, ultrasonography has a very low sensibility to detect cava vein thrombosis (16.7 %). The real meaning of our findings is unknown, but other temperature control systems could be a safer option. More studies are needed to confirm our findings.

Background: Dynamic cerebral autoregulation (DCA) is the continuous counterregulation of cerebral blood flow to fluctuations in blood pressure. DCA can become impaired after acute stroke, but it remains unclear to what extent and over what interval this occurs., Methods: We included 28 patients (NIHSS = 12 ± 6.5, age = 68.4 ± 17.1, 16F) with acute large-vessel ischemic stroke in the middle cerebral artery territory and 29 healthy controls (mean age 54.9 ± 9, 16F). DCA was assessed by simultaneous measurement of blood pressure together with blood flow velocities using finger plethysmography/arterial catheter and transcranial Doppler over three 10-minute recordings on days 0-2, 3-6 and ≥7 days after stroke. Transfer function analysis was applied to calculate average phase shift (PS) in the low frequency range (0.06-0.12 Hz). Less PS indicated poorer autoregulation. The affected side was compared with the unaffected side and controls. Univariate comparisons of data were performed using t tests at single time points, and generalized estimating equations with an exchangeable correlation matrix to examine the change in PS over time., Results: At mean 1.3 ± 0.5 days after stroke the average PS in the affected hemisphere was 29.6 ± 10.5 vs. 42.5 ± 13 degrees in the unaffected hemisphere (p = 0.004). At 4.1 ± 1 days, the PS in affected and unaffected hemisphere was 23.2 ± 19.1 vs. 41.7 ± 18.5 degrees, respectively (p = 0.003). At mean 9.75 ± 2.2 days stroke there was no difference between the affected and the unaffected hemisphere (53.2 ± 28.2 vs. 50.7 ± 29.2 degrees, p = 0.69). Control subjects had an average PS = 47.9 ± 16.8, significantly different from patients' affected hemisphere at the first two measurements (p = 0.001), but not the third (p = 0.37). The PS in controls remained unchanged on repeat testing after an average 19.1 days (48.4 ± 17.1, p = 0.61). Using the last recording as the reference, the average PS in the affected hemisphere was -23.54 (-44.1, -3) degrees lower on recording one (p = 0.025), and -31.6 (-56.1, -7.1) degrees lower on recording two (p < 0.011). Changes in the unaffected hemisphere over time were nonsignificant., Discussion: These data suggest that dynamic cerebral autoregulation is impaired in the affected hemisphere throughout the first week after large-vessel ischemic stroke, and then normalizes by week two. These findings may have important implications for acute blood pressure management after stroke., (© 2015 S. Karger AG, Basel.)

Background: Cerebral autoregulation (CA) enables the brain to maintain stable cerebral blood flow (CBF). CA can be assessed noninvasively by determining correlations between CBF velocity (CBFV) and spontaneous changes in blood pressure. Postrecording signal analysis methods have included both frequency- and time-domain methods. However, the test-retest reliability, cross-validation, and determination of normal values have not been adequately established., Methods: In 53 healthy volunteers, a transfer function analysis was applied to calculate phase shift (PS) and gain in the low frequency range (.06-.12 Hz) where CA is most apparent. Correlation analysis was used to derive mean velocity index (Mx). Intraclass correlation and bivariate correlation coefficients were applied to assess asymmetry, cross-validity, and test-retest results: The bihemispheric average PS, gain, and Mx means were 45.99+/-14.24°, .62+/-.38 cm/second/mmHg, and .41+/-.13, respectively. Gain exhibited a difference by age (P = .03). PS, gain, and Mx values showed excellent interhemispheric correlation (r > .8; P < .001). PS and gain showed good reliability (R ICC = .632, L ICC = .576; P < .001). PS and Mx showed fair correlation (r = -.37; P < .001)., Conclusions: CA parameters obtained by time- and frequency-domain methods correlate well, and show good interhemispheric and test-retest reliability. Group means from healthy controls may provide adequate norms for determining abnormal CA in cerebrovascular patients., (Copyright © 2013 by the American Society of Neuroimaging.)

Background: There is a growing interest in measuring cerebral autoregulation in patients with acute brain injury. Non-invasive finger photo-plethysmography (Finapres) is the method of choice to relate arterial blood pressure to changes in cerebral blood flow. Among acutely ill patients, however, peripheral vasoconstriction often limits the use of Finapres requiring direct intravascular blood pressure measurement. We evaluated how these two different forms of blood pressure monitoring affect the parameters of dynamic cerebral autoregulation (DCA)., Methods: We performed 37 simultaneous recordings of BP and cerebral blood flow velocity in 15 patients with acute brain injury. DCA was estimated in the frequency domain using transfer function analysis to calculate phase shift, gain, and coherence. In addition the mean velocity index (Mx) was calculated for assessment of DCA in the time domain., Results: The mean patient age was 58.1 ± 15.9 years, 80 % (n = 12) were women. We found good inter-method agreement between Finapres and direct intravascular measurement using Bland-Altman and correlation analyses. Finapres gives higher values for the efficiency of dynamic CA compared with values derived from radial artery catheter, as indicated by biases in the phase (26.3 ± 11.6° vs. 21.7 ± 10.5°, p = 0.001) and Mx (0.571 ± 0.137 vs. 0.649 ± 0.128, p < 0.001). Gain in the low frequency range did not significantly differ between the two arterial blood pressure methods. The average coherence between CBFV and ABP was higher when BP was measured with arterial catheter for frequencies above 0.05 Hz (0.8 vs. 0.73, p < 0.001)., Conclusion: Overall, both methods yield similar results and can be used for the assessment of DCA. However, there was a small but significant difference for both mean Mx and phase shift, which would need to be adjusted for during monitoring of patients when using both methods. When available, invasive arterial blood pressure monitoring may improve accuracy and thus should be the preferred method for DCA assessment in the ICU.

Background: There is a growing interest in measuring cerebral autoregulation in patients with acute brain injury. Non-invasive finger photo-plethysmography (Finapres) is the method of choice to relate arterial blood pressure to changes in cerebral blood flow. Among acutely ill patients, however, peripheral vasoconstriction often limits the use of Finapres requiring direct intravascular blood pressure measurement. We evaluated how these two different forms of blood pressure monitoring affect the parameters of dynamic cerebral autoregulation (DCA)., Methods: We performed 37 simultaneous recordings of BP and cerebral blood flow velocity in 15 patients with acute brain injury. DCA was estimated in the frequency domain using transfer function analysis to calculate phase shift, gain, and coherence. In addition the mean velocity index (Mx) was calculated for assessment of DCA in the time domain., Results: The mean patient age was 58.1 ± 15.9 years, 80 % (n = 12) were women. We found good inter-method agreement between Finapres and direct intravascular measurement using Bland–Altman and correlation analyses. Finapres gives higher values for the efficiency of dynamic CA compared with values derived from radial artery catheter, as indicated by biases in the phase (26.3 ± 11.6° vs. 21.7 ± 10.5°, p = 0.001) and Mx (0.571 ± 0.137 vs. 0.649 ± 0.128, p < 0.001). Gain in the low frequency range did not significantly differ between the two arterial blood pressure methods. The average coherence between CBFV and ABP was higher when BP was measured with arterial catheter for frequencies above 0.05 Hz (0.8 vs. 0.73, p < 0.001)., Conclusion: Overall, both methods yield similar results and can be used for the assessment of DCA. However, there was a small but significant difference for both mean Mx and phase shift, which would need to be adjusted for during monitoring of patients when using both methods. When available, invasive arterial blood pressure monitoring may improve accuracy and thus should be the preferred method for DCA assessment in the ICU.

Background: Nicardipine and labetalol are two commonly used antihypertensives for treating elevated blood pressures in the setting of intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH). There are no studies comparing these two agents as continuous infusions., Methods: A retrospective chart review was conducted of patients admitted between November 2009 and January 2011 with ICH and SAH to compare effectiveness and safety between both agents. Percent time spent at goal was set as the primary outcome. The secondary outcomes included blood pressure variability, time to goal, incidence of bradycardia, tachycardia, and hypotension., Results: A total of 81 patients were available for analysis, 10 initiated on labetalol (LAB), 57 on nicardipine (NIC), and 14 required the combination of these agents (COMB) to reach goal. We found no difference between NIC, LAB, and the COMB groups in the median percent time at goal [88 % (61-98); 93 % (51-99); 66 % (25-95), (p = NS)]. Median percentage of blood pressure variability, hypotension, and bradycardia were also comparable between groups, however, more tachycardia was observed in the COMB group versus both LAB and NIC groups (45 vs. 0 vs. 3 %; p < 0.001). Mean time to goal SBP in 24 patients who had BP readings available at 1st h of initiation was 32 ± 34 min in the NIC group and 53 ± 42 min in the LAB group (p = 0.03)., Conclusions: Both agents appear equally effective and safe for blood pressure control in SAH and ICH during the initial admission hours. A prospective study is needed to validate these findings.

Introduction: Delayed ischemic neurological deficit associated to cerebral vasospasm is the most common cause of sequelae and death that follows the rupture of an aneurysm. The objective of this study was to evaluate the safety and efficacy of intra-arterial Milrinone in patients with symptomatic refractory cerebral vasospasm., Patients and Method: Eight patients diagnosed with aneurysmal subarachnoid hemorrhage who developed symptomatic cerebral vasospasm refractory to conventional medical therapy were enrolled. They received an intra-arterial infusion of Milrinone at a rate of 0.25 mg/min, with a total dose of 10-15 mg. Qualitative evaluation of angiographic response, neurological and systemic complications as well as functional outcome at 3 months were documented., Results: All patients had a significant angiographic response. This was evidenced by a pre-treatment vessel stenosis greater than 70%, that improved to less than 50% after the intra-arterial Milrinone infusion. Three patients developed recurrent vasospasm that improved after a second intra-arterial Milrinone infusion. None of the patients developed neurologic or systemic complications attributed to the intervention. At 3 months follow-up all patients were alive and had a mean modified Rankin scale of 2 +/- 1 and a Barthel index of 83 +/- 10., Conclusion: Intra-arterial Milrinone infusion seems to be a safe and effective treatment for patients who develop refractory symptomatic cerebral vasospasm following aneurysmal subarachnoid hemorrhage.

Most studies evaluating the usefulness of intravenous thrombolysis for acute stroke have excluded subjects aged over 80 years. Therefore there is no evidence to support or contraindícate this therapy in this age group. We report a 93 year-old female subjected to intravenous thrombolysis using tissue plasminogen activator (r-tPA), according to the National Institute of Neurological Disorders protocol. The treatment was successful, there were no hemorrhagic complications and three months later, the patient was practically without any disability. Therefore age is not an absolute contraindication for intravenous thrombolysis in elderly subjects.