Internal Jugular Venous Research Articles

Variant of Lemierre's Syndrome Secondary to Trauma

Classic Lemierre's syndrome is a septic internal jugular venous (IJV) thrombophlebitis secondary to oropharyngeal anaerobic infection in adolescent and young adult. Though upper respiratory tract infection is the most common antecedent, it has also been described following skin, soft tissues, genitourinary and gastrointestinal infections. Fusobacteria necrophorum is the commonest pathogen isolated from blood and tissue cultures but other bacteria like Eikenella correndens, Bacteroides melaninogenicus and Non Group A Streptococcal species have also been reported. The overall incidence of Lemierre's and Lemierre's like syndromes has declined since the first case report in 1936. There is however, a resurgence of cases in recent years due to more judicious use of antibiotics for treatment of upper respiratory tract infection among medical practitioners. The main stay of treatment of complete Lemierre's syndrome is prolonged antibiotic coverage and surgical drainage of nonresolving abscesses. Currently, there is no consensus opinion on the use of anticoagulation in patient with complete Lemierre's syndrome complicated by septic internal jugular thrombosis and embolism. High index of suspicion is required for early diagnosis of Lemierre's and Lemierre's like syndromes. Early and effective antibiotics therapy may prevent the development full spectrum of the syndrome and its associated complication.

Hemodynamics of the Internal Jugular Vein: An Ultrasonographic Study

Objective To establish a simple classification of internal jugular venous flow using ultrasonography. Materials and Methods We retrospectively analyzed the sonographic findings of 1600 consecutive patients who were referred to the neurosono-graphic laboratory. Abnormal jugular venous flow was classified into five groups: (A) markedly decreased flow velocity; (B) stasis and/or thrombus formation; (C) reversed flow; (D) increased turbulent flow; and (E) pulsa-tile turbulent flow. Groups A to C were categorized as slow flow groups and groups D and E as high flow groups. Results Abnormal jugular venous flow was found in 182 (11%) patients. A slow flow pattern (73%) comprised the majority of abnormalities. Eightynine percent of patients in the slow flow groups had abnormalities in the left internal jugular vein (IJV) and 92% of those in the high flow groups had abnormalities in the bilateral IJV. Incompetence of the jugular valve was the most common cause of slow flow in the IJV. Most of the increased turbulent flow was found in patients with hyperthyroidism and in pregnant women. Arteriovenous malformation and carotid-cavernous fistula were the causes of pulsatile turbulent jugular venous flow. Associated clinical symptoms occurred in only two (1.5%) patients (with a concomitant left IJV and left subclavian vein thrombosis) in the slow flow groups, and in 34 (68%) patients in the high flow groups. Conclusion Most of the abnormally decreased jugular venous flow occurred on the left side. Decreased venous flow or even thrombosis of one side of the IJV was usually asymptomatic. Increased jugular flow was associated with a physiological hyperemic state in cerebral hemodynamics. Increased awareness and angiographic studies are indicated in patients with pulsatile turbulent jugular venous flow because of a high correlation with intracranial arteriovenous shunting.

Cerebral oxygenation decreases during exercise in humans with beta‐adrenergic blockade

Beta-blockers reduce exercise capacity by attenuated increase in cardiac output, but it remains unknown whether performance also relates to attenuated cerebral oxygenation. Acting as their own controls, eight healthy subjects performed a continuous incremental cycle test to exhaustion with or without administration of the non-selective beta-blocker propranolol. Changes in cerebral blood flow velocity were measured with transcranial Doppler ultrasound and those in cerebral oxygenation were evaluated using near-infrared spectroscopy and the calculated cerebral mitochondrial oxygen tension derived from arterial to internal jugular venous concentration differences. Arterial lactate and cardiac output increased to 15.3 +/- 4.2 mM and 20.8 +/- 1.5 L min(-1) respectively (mean +/- SD). Frontal lobe oxygenation remained unaffected but the calculated cerebral mitochondrial oxygen tension decreased by 29 +/- 7 mmHg (P < 0.05). Propranolol reduced resting heart rate (58 +/- 6 vs. 69 +/- 8 beats min(-1)) and at exercise exhaustion, cardiac output (16.6 +/- 3.6 L min(-1)) and arterial lactate (9.4 +/- 3.7 mM) were attenuated with a reduction in exercise capacity from 239 +/- 42 to 209 +/- 31 W (all P < 0.05). Propranolol also attenuated the increase in cerebral blood flow velocity and frontal lobe oxygenation (P < 0.05) whereas the cerebral mitochondrial oxygen tension decreased to a similar degree as during control exercise (delta 28 +/- 10 mmHg; P < 0.05). Propranolol attenuated the increase in cardiac output of consequence for cerebral perfusion and oxygenation. We suggest that a decrease in cerebral oxygenation limits exercise capacity.

Cerebral non‐oxidative carbohydrate consumption in humans driven by adrenaline

During brain activation, the decrease in the ratio between cerebral oxygen and carbohydrate uptake [6 O2/(glucose + 1/2lactate); OCI] is attenuated by the non‐selective beta‐adrenergic receptor antagonist propranolol, whereas OCI remains unaffected by the beta1‐adrenergic receptor antagonist metroprolol. These observations suggest involvement of a beta2‐adrenergic mechanism in non‐oxidative metabolism for the brain. Therefore, we evaluated the effect of adrenaline (0.08 micrograms kg‐1 min‐1 iv. for 15 min) and noradrenaline (0.5, 0.1 and 0.15 micrograms kg‐1 min‐1 iv. for 20 min) on the arterial to internal jugular venous concentration differences (a‐v diff) of O2, glucose, and lactate in healthy humans. Adrenaline (n=10) increased the arterial concentrations of O2, glucose and lactate (P &lt; 0.05) and also increased the a‐v diff for glucose from 0.6 ± 0.1 to 0.8 ± 0.2 mM (mean ± SD; P &lt; 0.05). The a‐v diff for lactate shifted from a net cerebral release to an uptake and OCI was lowered from 5.1 ± 1.5 to 3.6 ± 0.4 (P &lt; 0.05) indicating a 8‐fold increase in the rate of non‐oxidative carbohydrate uptake during adrenaline infusion (P &lt; 0.01). Conversely, noradrenaline (n=8) did not affect the OCI despite an increase in the a‐v diff for glucose (P &lt; 0.05). These results support that non‐oxidative carbohydrate consumption for the brain is driven by a beta2‐adrenergic mechanism, making neurons abundantly provided with energy when plasma adrenaline increases.

Cerebral non‐oxidative carbohydrate consumption in humans driven by adrenaline

During brain activation, the decrease in the ratio between cerebral oxygen and carbohydrate uptake (6 O(2)/(glucose + (1)/(2) lactate); the oxygen-carbohydrate index, OCI) is attenuated by the non-selective beta-adrenergic receptor antagonist propranolol, whereas OCI remains unaffected by the beta(1)-adrenergic receptor antagonist metroprolol. These observations suggest involvement of a beta(2)-adrenergic mechanism in non-oxidative metabolism for the brain. Therefore, we evaluated the effect of adrenaline (0.08 microg kg(-1) min(-1) i.v. for 15 min) and noradrenaline (0.5, 0.1 and 0.15 microg kg(-1) min(-1) i.v. for 20 min) on the arterial to internal jugular venous concentration differences (a-v diff) of O(2), glucose and lactate in healthy humans. Adrenaline (n = 10) increased the arterial concentrations of O(2), glucose and lactate (P < 0.05) and also increased the a-v diff for glucose from 0.6 +/- 0.1 to 0.8 +/- 0.2 mM (mean +/- s.d.; P < 0.05). The a-v diff for lactate shifted from a net cerebral release to an uptake and OCI was lowered from 5.1 +/- 1.5 to 3.6 +/- 0.4 (P < 0.05) indicating an 8-fold increase in the rate of non-oxidative carbohydrate uptake during adrenaline infusion (P < 0.01). Conversely, noradrenaline (n = 8) did not affect the OCI despite an increase in the a-v diff for glucose (P < 0.05). These results support that non-oxidative carbohydrate consumption for the brain is driven by a beta(2)-adrenergic mechanism, giving neurons an abundant provision of energy when plasma adrenaline increases.

The effects of normoxia, hypoxia, and hyperoxia on cerebral haemoglobin saturation using near infrared spectroscopy during maximal exercise

At rest, cerebral haemoglobin saturation ( S cO 2), obtained with near infrared spectroscopy (NIRS), tracks the calculated capillary-oxygenation-level-dependent (COLD) signal. However, the relationship between the two variables during maximal exercise is unknown. We evaluated S cO 2 by dual wavelengths NIRS (Somanetics INVOS) and calculated mean cerebral capillary oxygen saturation ( S capO 2) during maximal ergometer rowing in six subjects in normoxia, hypoxia (17% inspired O 2) and hyperoxia (30% O 2). We determined middle cerebral artery blood flow velocity by 2 MHz transcranial ultrasound Doppler, arterial ( S aO 2) and internal jugular venous O 2 saturation ( S vO 2). Maximal rowing reduced S aO 2, S vO 2 and S capO 2 ( P < 0.05) with no significant changes in S cO 2 compared to rest. Hyperoxia prevented, while hypoxia aggravated, the reductions in S aO 2 and S vO 2 ( P < 0.05). Across the range of inspired O 2, S aO 2 varied from 88.6 ± 2.4 to 98.3 ± 0.4% (mean ± SD), S vO 2 from 49.4 ± 8.4 to 64.4 ± 5.6%, and S capO 2 from 68.2 ± 0.5 to 81.1 ± 0.5% while the changes in S capO 2 were tracked by S cO 2 ( r 2 = 0.31; P < 0.01) with values for S cO 2 (63.8 ± 11.7%) being lower than those for S capO 2 (76.7 ± 6.0%; P < 0.05). The present data suggest that during maximal exercise S cO 2, though influenced significantly by venous blood, maintains a tight coupling with the calculated S capO 2. Relevance to industry Personnel working in industrial environments with low ambient oxygen partial pressure or high temperatures may face premature exhaustion from cerebral fatigue caused by low cerebral oxygenation. As cerebral oxygenation can be measured non-invasively during the vigorous movements associated with ergometer rowing, it can also be applied for field studies, e.g. during work in special environments including high altitude and high ambient pressure or temperature.

Incidental Contralateral Retrograde Internal Jugular Venous Catheterization via a Right External Jugular Venous Route - A case report -

We report of the occurrence of an incidental retrograde left internal jugular venous (IJV) catheterization during a right external jugular vein (EJV) approach.After induction of anesthesia, central venous catheterization was performed through the right EJV using the standard technique.There was no expected cardiac arrhythmia during guide wire insertion, and there was no atrial waveform on the CVP tracing.Therefore, we took a chest X-ray for confirmation of catheter placement, which revealed the tip was placed in the left IJV.We withdrew the catheter about 6−7 cm to prevent possible impairment of cerebral venous drainage by a retrograde-positioned catheter in the IJV.We think that the dilation of the left IJV due to Trendelenburg position, positive pressure ventilation, and the upward direction of the J-wire tip contributed to the contralateral retrograde IJV catheterization.We recommend that a chest X-ray always be taken if correct catheter tip placement is not confirmed during CVP catheterization.

Comparison of Catheter-related Infection and Tip Colonization between Internal Jugular and Subclavian Central Venous Catheters in Surgical Neonates

The primary aim of this study was to compare catheter-associated infections and tip contaminations between percutaneously placed central venous catheters in the internal jugular and subclavian veins in surgical neonates undergoing major noncardiac surgery. The prospectively computerized protocols of 295 procedures were analyzed retrospectively. One hundred twenty-nine internal jugular venous (group I) and 107 subclavian venous catheters (group S) were included. The median postconceptual age was 37 weeks in group I and 38 in group S. The weight ranged from 580 g to 4.5 kg in group I and from 820 g to 4.5 kg in group S at the time of insertion. Significantly more catheter-associated infections were observed in group I (15.5 vs. 4.7%; chi-square analysis: P < 0.01). The internal jugular venous catheters were also associated with a significantly increased probability of an earlier onset of a catheter-associated infection compared with the subclavian venous catheters (log rank test: P < 0.01; Cox model: P < 0.01). This probability was only slightly increased by a lower weight (Cox model: P = 0.075), and it was not increased by a lower age (Cox model: P = 0.93). Significantly more catheter tips were contaminated by pathogens in group I (55.8 vs. 33.6%; chi-square analysis: P < 0.01). The internal jugular venous catheters were associated with a higher infection rate as well as earlier onset of catheter-associated infection compared with the subclavian venous catheters.

Circumferential Adjustment of Ultrasound Probe Position to Determine the Optimal Approach to the Internal Jugular Vein: A Noninvasive Geometric Study in Adults

Circumferential adjustment of the position of a two-dimensional ultrasound (US) probe around the neck has been recommended as a strategy for reducing the potential for unintentional common carotid artery puncture during internal jugular venous (IJV) cannulation. We obtained multiple high-resolution US images bilaterally from the necks of 107 adult subjects and analyzed these to determine the degree to which this strategy permits identification of a pathway from the skin to the IJV that minimizes venoarterial overlap while maximizing venous target (angular) width. The method consistently permitted identification of an approach to the IJV superior to that obtainable with any one of four popular surface anatomy-based ("blind") approaches and was even more powerful if used in concert with a US-guided 1) adjustment of the degree of head rotation, 2) choice between a high and low approach, and 3) choice between the right and left IJV. Use of a high-resolution US imaging device also permitted identification of the precise boundaries of additional cervical anatomic structures (nontarget vessels, lymph nodes, and the thyroid gland) potentially relevant to selection of an optimal approach to the IJV.

Relationship between Tinnitus Loudness Level and Internal Jugular Venous Flow Rate Measured by Coloured Doppler Ultrasonography in Patients with a High Jugular Bulb

The aim of this study was to investigate the relationship between tinnitus loudness level (TLL) and internal jugular venous flow rate (IJVFR) in tinnitus patients with a unilateral high jugular bulb detected by temporal bone high-resolution computed tomography (HRCT). The study group consisted of 24 adult patients (13 male, 11 female) with a unilateral high jugular bulb. One ear suffered from tinnitus with a high jugular bulb was included into the study group. The ears without tinnitus and no high jugular bulb on temporal bone HRCT comprised the control group. All patients were evaluated with a history and physical and otolaryngologic examinations, and, using a questionnaire, TLLs were detected. The patency and flow rates in the internal jugular veins were measured by right and left internal jugular venous Doppler ultrasonography. The TLLs were "very quiet" in 1 (4.1%) patient, "intermediate loud" in 17 (70.9%) patients, and "very loud" in 6 (25.0%) patients. IJVFRs were not different in the study and control groups. In the study group, IJVFRs were not correlated with age. There was no relationship among TLLs and IJVFRs, dominance, dehiscence, and bony septum thickness between the high jugular bulb and the middle ear. TLLs were not affected by IJVFRs, dominance, dehiscence, and bony septum thickness in patients with a high jugular bulb. More detailed studies should be undertaken to determine the reason for the different TLLs in patients with a high jugular bulb.

Exercise induces the release of heat shock protein 72 from the human brain in vivo

The present study tested the hypothesis that in response to physical stress the human brain has the capacity to release heat shock protein 72 (Hsp72) in vivo. Therefore, 6 humans (males) cycled for 180 minutes at 60% of their maximal oxygen uptake, and the cerebral Hsp72 response was determined on the basis of the internal jugular venous to arterial difference and global cerebral blood flow. At rest, there was a net balance of Hsp72 across the brain, but after 180 minutes of exercise, we were able to detect the release of Hsp72 from the brain (335 +/- 182 ng/min). However, large individual differences were observed as 3 of the 6 subjects had a marked increase in the release of Hsp72, whereas exercise had little effect on the cerebral Hsp72 balance in the remaining 3 subjects. Given that cerebral blood flow was unchanged during exercise compared with values obtained at rest, it is unlikely that the cerebral Hsp72 release relates to necrosis of specific cells within the brain. These data demonstrate that the human brain is able to release Hsp72 in vivo in response to a physical stressor such as exercise. Further study is required to determine the biological significance of these observations.

Placement of Tunnelled Hemodialysis Catheters across Stenotic and Occluded Central Veins

Purpose The purpose of this study was to evaluate the efficacy of placement of tunneled hemodialysis catheters in patients with occluded or stenotic central veins. Materials and Methods Data were prospectively collected for 26 patients (11 male, 15 female, mean age 52 years) referred for placement of tunneled hemodialysis catheters with central venous stenoses or occlusions. The central venous occlusions or stenoses were recanalized using traditional interventional catheter and guidewire techniques. Results Thirty central venous access procedures were performed of which 28 (93%) procedures resulted in successful tunneled catheter insertion. Twenty-one internal jugular venous (13 right, 8 left) and 7 subclavian venous (3 right, 4 left) catheters were placed. Eighteen stenotic and 10 occluded venous segments were crossed including the brachiocephalic vein (n = 22), subclavian vein (n = 2), and the superior vena cava (4). One patient required insertion of a metallic stent to facilitate passage of the hemodialysis catheter across an occluded brachiocephalic vein. No procedure-related complications occurred. No episodes of upper extremity swelling or superior vena cava syndrome occurred following catheter insertion. Conclusion Insertion of tunneled hemodialysis catheter across occluded or stenotic central veins is technically feasible and safe. The use of occluded or stenotic central veins for catheter access preserves patent central veins for future shunt access.

Interleukin-6 release from the human brain during prolonged exercise.

Interleukin (IL)-6 is a pleiotropic cytokine, which has a variety of physiological roles including functions within the central nervous system. Circulating IL-6 increases markedly during exercise, partly due to the release of IL-6 from the contracting skeletal muscles, and exercise-induced IL-6 may be linked with central fatigue, which is enhanced by hyperthermia. Exercise-induced IL-6 may also stimulate hepatic glycogenolysis, which is important during prolonged and repeated exercise. Thus, in a randomised order and separated by 60 min of rest, eight young male subjects completed two 60 min exercise bouts: one bout with a normal (38 degrees C) and the other with an elevated (39.5 degrees C) core temperature. The cerebral IL-6 response was determined on the basis of internal jugular venous to arterial IL-6 differences and global cerebral blood flow. There was no net release or uptake of IL-6 in the brain at rest or after 15 min of exercise, but a small release of IL-6 was observed after 60 min of exercise in the first bout (0.06 +/- 0.03 ng min(-1)). This release of IL-6 from the brain was five-fold greater at the end of the second bout (0.30 +/- 0.08 ng min(-1); P < 0.05) with no separate influence of hyperthermia. In conclusion, IL-6 is released from the brain during prolonged exercise in humans and it appears that the duration of the exercise rather than the increase in body temperature dictates the cerebral IL-6 response.

Disturbance of venous flow patterns in patients with transient global amnesia

Transient global amnesia (TGA) is an inability to form new memories. The pathophysiology and cause of TGA have not been defined. We examined the changes of internal jugular venous flow patterns in 21 patients with TGA and 21 age-matched and sex-matched controls using duplex ultrasonography during two Valsalva manoeuvres (blocking venous return through the superior vena cava). During both manoeuvres a retrograde flow component was seen significantly more frequently in the TGA group than in the controls. Ten patients reported Valsalva-like activities preceding TGA. In these patients a retrograde flow component took place more frequently than in those who did not report preceding Valsalva-like activities. Our results lend support to the hypothesis that TGA may be attributable to venous congestion, and consequent venous ischaemia to bilateral diencephalic or hippocampal structures.

Differential perfusion: a new technique for isolated brain cooling during cardiopulmonary bypass

Background. The purpose of this study was to determine the feasibility of differential perfusion of the aortic arch and descending aorta during cardiopulmonary bypass using a cannula designed for aortic segmentation.Methods. Pigs weighing 57 kg (n = 8), underwent cardiopulmonary bypass using the dual lumen aortic cannula. An inflatable balloon separated proximal (aortic arch) and distal (descending aorta) ports. During differential perfusion, the aorta was segmented and the arch and descending aorta perfused differentially using parallel heat exchangers. Ability to independently control brain and body temperature, cardiopulmonary bypass flow rate and mean arterial blood pressure was determined.Results. During differential perfusion cerebral hypothermia (27°C) with systemic normothermia (38°C) was established in 23 minutes. Independent control of arch and descending aortic flow and mean arterial blood pressure was possible. Analysis of internal jugular venous O2 saturation data indicated an increase in the ratio of cerebral O2 supply to demand during differential perfusion.Conclusions. A cannulation system segmenting the aorta allows independent control of cerebral and systemic perfusion. This device could provide significant cerebral protection while maintaining the advantages of warm systemic cardiopulmonary bypass temperatures.

Increase in jugular levels of polymorphonuclear neutrophil elastase in patients with acute cerebral infarction

To elucidate the involvement of activated polymorphonuclear neutrophil (PMN) proteolytic activity in the pathophysiology of cerebrovascular stroke, we measured internal jugular venous and femoral arterial levels of PMN elastase in 6 patients with acute stroke from the day of onset (day 0) to 7 days after onset (day 7). Two patients with cerebral infarction demonstrated markedly elevated levels of PMN elastase in the jugular blood (730 and 1320 µg l-1, respectively), but not in the arterial blood (203 and 205 µg l-1, respectively) on day 2. Both patients manifested signs of hemorrhagic infarction early on day 2. On day 4, the increased levels ofjugular PMN elastase returned to the normal range (250 µg l-1, in both patients. In contrast, none of the 4 patients with intracerebral hemorrhage demonstrated increased levels ofPMN elastase in either the jugular or the arterial blood from days 0 to 7. The present study demonstrated a temporary but significant increase in jugular PMN elastase in patients with cerebral infarction, especially shortly after hemorrhagic infarction. [Neural Res 1998; 20: 397–402]

Inhibition of progression of chronic puromycin aminonucleoside nephrosis by probucol, an antioxidant.

Oxidants have been shown to be involved in the initiation of chronic puromycin aminonucleoside nephrosis in rats, but it is uncertain whether they have a role in the progression of this disease. Rats given a single internal jugular venous bolus of puromycin aminonucleoside (PA) develop early nephrotic syndrome that subsides after about 28 days followed by a 4-wk period of minimal proteinuria and then the development of focal glomerulosclerosis and increasing proteinuria. Fifty-two rats on a high-cholesterol diet were divided into four groups. Two groups of 16 animals each received a single internal jugular venous bolus of PA. One of these groups was started on the dietary antioxidant, probucol (1% wt/wt), 4 days after the PA injection and continued on it until termination. The remaining rats were given an internal jugular venous injection of an equivolume of normal saline. Five of these animals were also started on dietary probucol 4 days after the saline injection. At 11 days postinjection all animals given PA, whether on probucol or not, developed marked proteinuria with histologically minimal glomerular change and significant increases in intraglomerular monocyte and proliferating cell nuclear antigen counts. Forty-two days after PA injection all PA-injected rats had minimal urinary protein injection and no glomerular changes. At 98 days postinjection rats given PA without probucol developed focal glomerulosclerosis and significant proteinuria compared with PA-injected rats on probucol and those injected with saline (P < 0.05). The probucol-fed PA-injected rats showed no glomerular disease and their urinary protein excretion rates were very similar to those of the saline controls. The results indicate that probucol inhibits the progression of chronic puromycin aminonucleoside nephrosis and are consistent with the suggestion that oxidants are involved in the progression of this entity.

Noninvasive Measurement of Central Venous Pressure by Neck Inductive Plethysmography

Bedside estimation of the height at which the internal jugular veins collapse, referenced to a standard hemodynamic location, theoretically reflects central venous pressure. This method has never been demonstrated as accurate when compared to invasive CVP measurements because of the great clinical skills and time required to visually identify the internal jugular venous waveform. Since the principles of the bedside method are sound, we utilized them in conjunction with the neck inductive plethysmograph, a device which has the capability of recording internal jugular venous and carotid arterial waveforms. The respiratory distortion of these vascular waveforms was eliminated by employing a digital bandpass filter, making it easy to identify the venous and arterial waveforms on the videoscreen of a personal computer. The upper torso was positioned while observing the videoscreen until the vascular waveform was seen as a mixed arteriovenous waveform, signifying intermittent internal jugular venous collapse. The height of the internal jugular vein above the phlebostatic axis was obtained by external measurement and recorded as CVPni in cm H 2 O. In 43 patients, 86 percent of CVPni (NIP) values fell within 20 percent CVPi (invasive catheter measurements) over a range of CVP from 0 to 19 cm H 2 O. In an additional seven patients, CVPi was greater than the height that the upper torso could be elevated and an arterial waveform could not be obtained. Here, CVPni was recorded as the value at least exceeding the value measured. In two other patients, obstruction of an internal jugular vein gave spuriously low values of CVPni. Our study indicates that this new neck inductive plethysmographic method is accurate compared to invasive catheter measurements of CVP and should serve as a safe, noninvasive alternative in situations where such measurements are required. (Chest 1991; 100:371-75)

Noninvasive Measurement of Central Venous Pressure by Neck Inductive Plethysmography

Bedside estimation of the height at which the internal jugular veins collapse, referenced to a standard hemodynamic location, theoretically reflects central venous pressure. This method has never been demonstrated as accurate when compared to invasive CVP measurements because of the great clinical skills and time required to visually identify the internal jugular venous waveform. Since the principles of the bedside method are sound, we utilized them in conjunction with the neck inductive plethysmograph, a device which has the capability of recording internal jugular venous and carotid arterial waveforms. The respiratory distortion of these vascular waveforms was eliminated by employing a digital bandpass filter, making it easy to identify the venous and arterial waveforms on the videoscreen of a personal computer. The upper torso was positioned while observing the videoscreen until the vascular waveform was seen as a mixed arteriovenous waveform, signifying intermittent internal jugular venous collapse. The height of the internal jugular vein above the phlebostatic axis was obtained by external measurement and recorded as CVPni in cm H2O. In 43 patients, 86 percent of CVPni (NIP) values fell within 20 percent CVPi (invasive catheter measurements) over a range of CVP from 0 to 19 cm H2O. In an additional seven patients, CVPi was greater than the height that the upper torso could be elevated and an arterial waveform could not be obtained. Here, CVPni was recorded as the value at least exceeding the value measured. In two other patients, obstruction of an internal jugular vein gave spuriously low values of CVPni. Our study indicates that this new neck inductive plethysmographic method is accurate compared to invasive catheter measurements of CVP and should serve as a safe, noninvasive alternative in situations where such measurements are required.

Internal jugular venous flow measurement by means of a duplex scanner.

Using a special probe holder, cross-sectional area and time-averaged mean spatial velocity of the internal jugular vein were measured by means of a duplex scanner and multiplied to calculate volume flow. In a cohort of 100 subjects ages 21 to 70 years, average right plus left flow was 740 +/- 209 mL/min. Flow was 8.7% lower in females than in males. Normalization of flow to 100 g brain tissue by dividing it through the mean sex specific brain weight resulted in no significant sex difference. Within the age range investigated, there was no decrease of flow with age.