Ultrasound is a reliable method for determining jugular bulb dominance

A Prospective Observational Feasibility Study of Jugular Bulb Microdialysis in Subarachnoid Hemorrhage

BACKGROUND

Cerebral metabolic perturbations are common in aneurysmal subarachnoid hemorrhage (aSAH). Monitoring cerebral metabolism with intracerebral microdialysis (CMD) allows early detection of secondary injury and may guide decisions on neurocritical care interventions, affecting outcome. However, CMD is a regional measuring technique that is influenced by proximity to focal lesions. Continuous microdialysis of the cerebral venous drainage may provide information on global cerebral metabolism relevant for the care of aSAH patients. This observational study aimed to explore the feasibility of jugular bulb microdialysis (JBMD) in aSAH and describe the output characteristics in relation to conventional multimodal monitoring.

METHODS

Patients with severe aSAH were included at admission or after in-house deterioration when local clinical guidelines prompted extended multimodal monitoring. Non-dominant frontal CMD, intracranial pressure (ICP), partial brain tissue oxygenation pressure (PbtO₂), and cerebral perfusion pressure (CPP) were recorded every hour. The dominant jugular vein was accessed by retrograde insertion of a microdialysis catheter with the tip placed in the jugular bulb under ultrasound guidance. Glucose, lactate, pyruvate, lactate/pyruvate ratio, glycerol, and glutamate were studied for correlation to intracranial measurements. Modified Rankin scale was assessed at 6 months.

RESULTS

Twelve adult aSAH patients were monitored during a mean 4.2 ± 2.6 days yielding 22,041 data points for analysis. No complications related to JBMD were observed. Moderate or strong significant monotonic CMD-to-JBMD correlations were observed most often for glucose (7 patients), followed by lactate (5 patients), and pyruvate, glycerol, and glutamate (3 patients). Moderate correlation for lactate/pyruvate ratio was only seen in one patient. Analysis of critical periods defined by ICP > 20, CPP < 65, or PbtO₂ < 15 revealed a tendency toward stronger CMD-to-JBMD associations in patients with many or long critical periods. Possible time lags between CMD and JBMD measurements were only identified in 6 out of 60 patient variables. With the exception of pyruvate, a dichotomized outcome was associated with similar metabolite patterns in JBMD and CMD. A nonsignificant tendency toward greater differences between outcome groups was seen in JBMD.

CONCLUSIONS

Continuous microdialysis monitoring of the cerebral drainage in the jugular bulb is feasible and safe. JBMD-to-CMD correlation is influenced by the type of metabolite measured, with glucose and lactate displaying the strongest associations. JBMD lactate correlated more often than CMD lactate to CPP, implying utility for detection of global cerebral metabolic perturbations. Studies comparing JBMD to other global measures of cerebral metabolism, e.g., PET CT or Xenon CT, are warranted.

Head of bed elevation in pediatric patients with severe traumatic brain injury

OBJECTIVE

Head of bed (HOB) elevation to 30° after severe traumatic brain injury (TBI) has become standard positioning across all age groups. This maneuver is thought to minimize the risk of elevated ICP in the hopes of decreasing cerebral blood and fluid volume and increasing cerebral venous outflow with improvement in jugular venous drainage. However, HOB elevation is based on adult population data due to a current paucity of pediatric TBI studies regarding HOB management. In this prospective study of pediatric patients with severe TBI, the authors investigated the role of different head positions on intracranial pressure (ICP), cerebral perfusion pressure (CPP), and cerebral venous outflow through the internal jugular veins (IJVs) on postinjury days 2 and 3 because these time periods are considered the peak risk for intracranial hypertension.

METHODS

Patients younger than 18 years with a Glasgow Coma Scale score ≤ 8 after severe TBI were prospectively recruited at a single quaternary pediatric intensive care unit. All patients had an ICP monitor placed, and no other neurosurgical procedure was performed. On the 2nd and 3rd days postinjury, the degree of HOB elevation was varied between 0° (head-flat or horizontal), 10°, 20°, 30°, 40°, and 50° while ICP, CPP, and bilateral IJV blood flows were recorded.

RESULTS

Eighteen pediatric patients with severe TBI were analyzed. On each postinjury day, 13 of the 18 patients had at least 1 optimal HOB position (the position that simultaneously demonstrated the lowest ICP and the highest CPP). Six patients on each postinjury day had 30° as the optimal HOB position, with only 2 being the same patient on both postinjury days. On postinjury day 2, 3 patients had more than 1 optimal HOB position, while 5 patients did not have an optimal position. On postinjury day 3, 2 patients had more than 1 optimal HOB position while 5 patients did not have an optimal position. Interestingly, 0° (head-flat or horizontal) was the optimal HOB position in 2 patients on postinjury day 2 and 3 patients on postinjury day 3. The optimal HOB position demonstrated lower right IJV blood flow than a nonoptimal position on both postinjury days 2 (p = 0.0023) and 3 (p = 0.0033). There was no significant difference between optimal and nonoptimal HOB positions in the left IJV blood flow.

CONCLUSIONS

In pediatric patients with severe TBI, the authors demonstrated that the optimal HOB position (which decreases ICP and improves CPP) is not always at 30°. Instead, the optimal HOB should be individualized for each pediatric TBI patient on a daily basis.

Is jugular bulb oximetry monitoring associated with outcome in out of hospital cardiac arrest patients?

Cerebral protection against secondary hypoxic-ischemic brain injury is a key priority area in post-resuscitation intensive care management in survivors of cardiac arrest. Nevertheless, the current understanding of the incidence, diagnosis and its’ impact on neurological outcome remains undetermined. The aim of this study was to evaluate jugular bulb oximetry as a potential monitoring modality to detect the incidences of desaturation episodes during post-cardiac arrest intensive care management and to evaluate their subsequent impact on neurological outcome. We conducted a prospective, observational study in unconscious adult patients admitted to the intensive care unit who had successful resuscitation following out of hospital cardiac arrest of presumed cardiac causes. All the patients were treated as per European Resuscitation Council 2015 guidelines and they received jugular bulb catheter. Jugular bulb oximetry measurements were performed at six hourly intervals. The neurological outcomes were evaluated on 90th day after the cardiac arrest by cerebral performance categories scale. Forty patients met the eligibility criteria. Measurements of jugular venous oxygen saturation were performed for 438 times. Altogether, we found 2 incidences of jugular bulb oxygen saturation less than 50% (2/438; 0.46%), and 4 incidences when it was less than 55% (4/438; 0.91%). The study detected an association between SjVO₂ and CO₂ (r = 0.26), each 1 kPa increase in CO₂ led to an increase in SjvO₂ by 3.4% + / − 0.67 (p < 0.0001). There was no association between SjvO₂ and PaO₂ or SjvO₂ and MAP. We observed a statistically significant higher mean SjvO₂ (8.82% + / − 2.05, p < 0.0001) in unfavorable outcome group. The episodes of brain hypoxia detected by jugular bulb oxygen saturation were rare during post-resuscitation intensive care management in out of hospital cardiac arrest patients. Therefore, this modality of monitoring may not yield any additional information towards prevention of secondary hypoxic ischemic brain injury in post cardiac arrest survivors. Other factors contributing towards high jugular venous saturation needs to be considered.

My paper 20 years later: cerebral venous oxygen saturation studied with bilateral samples in the internal jugular veins

INTRODUCTION

Jugular oxygen saturation monitoring was introduced in neurointensive care after severe traumatic brain injury (TBI) to explore the adequacy of brain perfusion and guide therapeutic interventions. The brain was considered homogeneous, and oxygen saturation was taken as representative of the whole organ. We investigated whether venous outflow from the brain was homogeneous by measuring oxygen saturation simultaneously from the two jugular veins.

METHODS

In 32 comatose TBI patients both internal jugular veins (IJs) were simultaneously explored using intermittent samples; hemoglobin saturation was also recorded continuously by fiber-optic catheters in five patients. In five cases long catheters were inserted bilaterally upstream, up to the sigmoid sinuses.

MAIN FINDINGS

On average, measurements from the two sides were in agreement (mean and standard deviation of the differences between the saturation of the two IJs were respectively 5.32 and 5.15). However, 15 patients showed differences of more than 15 % in hemoglobin saturation at some point; three others showed differences larger than 10 %. No relationship was found between the computed tomographic scan data and the hemoglobin saturation pattern.

DISCUSSION/CONCLUSION

Several groups have confirmed differences between oxygen saturation in the two jugular veins. After years of enthusiasm, interest for jugular saturation has decreased and more modern methods, such as tissue oxygenation monitoring, are now available. Jugular saturation monitoring has low sensitivity, with the risk of missing low saturation, but high specificity; moreover it is cheap, when used with intermittent sampling. Monitoring the adequacy of brain perfusion after severe TBI is essential. However the choice of a specific monitor depends on local resources and expertise.

CT arteriography and venography in the evaluation of Pulsatile tinnitus with normal otoscopic examination

OBJECTIVES/HYPOTHESIS

Our retrospective study aims to assess the ability of computed tomography arteriography and venography (CT A/V) to detect various findings that suggest a potential cause of pulsatile tinnitus and to examine the association between these findings and the side of pulsatile tinnitus.

STUDY DESIGN

A retrospective review of CT arteriography and venography of 32 patients with established pulsatile tinnitus and normal otoscopic examination was performed. The scans were performed using a 64-slice multidetector scanner and were reviewed to look for findings that are known to cause pulsatile tinnitus.

RESULTS

One or more findings that are known to cause pulsatile tinnitus were detected on the symptomatic side in 30 patients; on the asymptomatic side in 3 patients, one patient with bilateral pulsatile tinnitus showed a potential cause of symptoms only on one side, and in one patient no potential cause could be identified. There is a significant association seen between the side of pulsatile tinnitus and various potential causes of pulsatile tinnitus detected (P < 0.001), between the side of pulsatile tinnitus and various potential venous cause detected (P < 0.001), and between the side of pulsatile tinnitus and the side of dominant venous system (P = 0.02).

CONCLUSION

CT arteriography and venography is a useful tool in detecting many described potential causes of pulsatile tinnitus. Significant association is demonstrated between the side of pulsatile tinnitus and the potential causes of pulsatile tinnitus detected by CT arteriography and venography when the otoscopic examination is normal.

Cost effectiveness analysis of using multiple neuromodalities in treating severe traumatic brain injury in a developing country like Malaysia

OBJECTIVE

The aim of this study was to determine the cost-effectiveness of using baseline neuromonitoring (BNM) compared with multimodality monitoring (M3) for severe traumatic brain injury (TBI).

METHODS

Sixty-two patients with severe TBI underwent a prospective observational study where they were divided into two groups of patients receiving treatment with M3 (32 patients) and BNM (30 patients). The macro and micro costings were performed on each patient. The Barthel Index score after 1 year was used as an outcome measurement tool for both groups. The cost-effectiveness (CE) ratio was calculated using the Poisson regression model.

RESULTS

The costs of equipment and consumables between the groups was statistically significant (p < 0.001) after correcting for age and severity of injury. Other cost categories were not significantly different. The crude CE ratios were 168.66 (95% CI: 168.32, 169.03) and 144.16 (95% CI: 143.87, 144.45) for BNM and M3 respectively. The two crude CE ratios were significantly different (p < 0.001). It was calculated by controlling or adjusting age, gender, Glasgow Coma Score, Marshalls classification at admission and type of injury. The adjusted CE ratios were 171.32 (95% CI: 170.97, 171.68) and 141.50 (95% CI: 141.26, 141.79) for BNM and M3, respectively. The two adjusted CE ratios were significantly different ( p< 0.001).

CONCLUSION

The application of M3 for severe TBI was more cost-effective than BNM. All calculations were made at 3.8 Malaysian Ringgit (MYR) to the United States dollar (USD).

The acute care of traumatic brain injury

During the past few decades, management of acute traumatic brain injury has advanced substantially on several fronts. Implementation of rapid transport systems and the advent of trauma centres, together with advances in emergency medicine, critical care medicine and trauma neurosurgery, have improved outcome following head injury. Technological advances made during the past years in the field of invasive neuromonitoring that provide real-time information on brain oxygenation may further improve outcome by enabling individualized therapies for intracranial hypertension. Furthermore, these recent technological advances will provide insights into the pathophysiological processes that are active in traumatic brain injury and a better understanding of the biochemical effects of specific therapeutic regimens.

Bilateral duplicated internal jugular veins: Case study and literature review

A rare bilateral duplication of the internal jugular vein (IJV) was discovered during cadaveric dissection. From each jugular foramen, a single IJV descended to the level of the hyoid bone then divided into medial and lateral veins. The medial IJVs traveled in the carotid sheath; the lateral IJVs coursed posterolateral to the sheath across the lateral cervical region (posterior triangle) of the neck. On the right side, medial and lateral IJVs entered the subclavian vein separately. C2-C3 anterior rami and the suprascapular artery passed between the medial and lateral IJVs. The right external jugular vein passed aberrantly between the heads of the sternocleidomastoid muscle (SCM) into the subclavian vein anterior to the lateral IJV. On the left side, the medial IJV drained into a large bulbous jugulovertebrosubclavian (JVS) sinus that received six main vessels. The lateral IJV diverged posterolaterally toward the border of the trapezius muscle, received the transverse cervical vein, and then turned sharply anteromedially to drain into the JVS sinus. The lateral IJV also gave an aberrant additional large vein that passed laterally around the omohyoid muscle before entering the JVS sinus. The left external jugular vein paralleled the anterior border of SCM before passing posterolaterally to terminate in the JVS sinus. Jugular vein anomalies of this magnitude are very rare. Determining the frequency of multiple IJVs is hampered by inconsistent terminology. We suggest that IJV duplication differs from fenestration anatomically and, potentially, developmentally. Criteria for characterizing IJV duplication and fenestration are proposed. The mechanism of development and the clinical significance of multiple IJVs are discussed.

Fuelling cerebral activity in exercising man

The metabolic response to brain activation in exercise might be expressed as the cerebral metabolic ratio (MR; uptake O2/glucose + 1/2 lactate). At rest, brain energy is provided by a balanced oxidation of glucose as MR is close to 6, but activation provokes a 'surplus' uptake of glucose relative to that of O2. Whereas MR remains stable during light exercise, it is reduced by 30% to 40% when exercise becomes demanding. The MR integrates metabolism in brain areas stimulated by sensory input from skeletal muscle, the mental effort to exercise and control of exercising limbs. The MR decreases during prolonged exhaustive exercise where blood lactate remains low, but when vigorous exercise raises blood lactate, the brain takes up lactate in an amount similar to that of glucose. This lactate taken up by the brain is oxidised as it does not accumulate within the brain and such pronounced brain uptake of substrate occurs independently of plasma hormones. The 'surplus' of glucose equivalents taken up by the activated brain may reach approximately 10 mmol, that is, an amount compatible with the global glycogen level. It is suggested that a low MR predicts shortage of energy that ultimately limits motor activation and reflects a biologic background for 'central fatigue'.