The effect of laryngeal mask airway insertion on the position of the internal jugular vein

Prehospital Supraglottic Airways: An NAEMSP Position Statement and Resource Document

Supraglottic airway (SGA) devices provide effective conduits for oxygenation and ventilation and may offer protection from gastric aspiration. SGA devices are widely used by EMS clinicians as both rescue and primary airway management devices. While in common use for more than four decades, major developments in SGA education, science, and technology have influenced clinical strategies of SGA insertion and use in prehospital airway management for patients of all ages. NAEMSP recommends:SGAs have utility as a primary or secondary EMS airway intervention. EMS agencies should select SGA strategies that best suit available resources and local clinician skillset, as well as the nature of their clinical practice setting.EMS agencies that perform endotracheal intubation must also equip their clinicians with SGA devices and ensure adequate training and competence.In select situations, drug-assisted airway management may be used by properly credentialed EMS clinicians to facilitate SGA insertion.Confirmation of initial and continuous SGA placement using waveform capnography is strongly encouraged as a best practice.When it is functioning properly, EMS clinicians should refrain from converting an SGA to an endotracheal tube. The decision to convert an SGA to an endotracheal tube must consider the patient's condition, the effectiveness of SGA ventilations, and the clinical context and course of initial SGA insertionSGA training, competency, and clinical use must be continuously evaluated by EMS agencies using focused quality management programs.

Effect of different types of laryngeal mask airway placement on the right internal jugular vein: A prospective randomized controlled trial

BACKGROUND

In recent years, with the popularity of laryngeal mask airway (LMA) for the management of clinical anesthesia, the influence of the LMA on the position and blood flow of the internal jugular vein (IJV) has attracted an increasing amount of attention.

AIM

To investigate the effect of placement of different types of LMA (Supreme LMA, Guardian LMA, I-gel LMA) on the position and blood flow of the right IJV.

METHODS

This was a prospective randomized controlled trial. A total of 102 patients aged 18-75 years who were scheduled to undergo laparoscopic abdominal surgery with general anesthesia were randomly assigned to three groups: Supreme LMA (group 1), Guardian LMA (group 2), and I-gel LMA (group 3) groups. The main indicator was the overlap index (OI) of IJV and the common carotid artery (CCA) at the high, middle, and low points before and after the placement of the LMA. The second indicators were the proportion of ultrasound-simulated needle crossing the IJV and CCA, and the cross-sectional area and blood flow velocity of the IJV before and after placement of the LMA at the middle point.

RESULTS

Data from 100 patients were included in the statistical analysis. The OI increased significantly after placement of the LMA in the three groups at the three points (P < 0.01), except group 2 at the low point. In group 2 and group 3, the OI was lower than that in group 1 after LMA insertion at the high point (P < 0.0167). At the middle point, after LMA insertion, the proportion of simulated needle crossing the IJV significantly decreased in all three groups (P < 0.05), and the proportion in group 2 was higher than that in group 3 (P < 0.0167). The proportion of simulated needle crossing the CCA or both the IJV and CCA significantly increased in group 1 and group 2 (P < 0.05), which increased with no statistical significance in group 3. After LMA insertion, the cross-sectional area of ​​the IJV significantly increased, while the blood flow velocity significantly decreased (P < 0.01). There was no significant difference among the three groups.

CONCLUSION

The placement of Supreme, Guardian, and I-gel LMA can increase the OI, reduce the success rate of IJV puncture, increase the incidence of arterial puncture, and cause congestion of IJV. Type of LMA did not influence the difficulty of IJV puncture. Therefore when LMA is used, ultrasound is recommended to guide the IJV puncture.

Effect of Positive End-Expiratory Pressure on Overlap Between Internal Jugular Vein and Carotid Artery in Mechanically Ventilated Patients with Laryngeal Mask Airway (LMA) Insertion - A Prospective Randomized Trial

Background

In the present study, we aimed to determine the effect of different positive end-expiratory pressure (PEEP) levels on the cross-sectional area (CSA) of the right internal jugular vein (RIJV) and the overlap index between the RIJV and the right common carotid artery (RCCA) in mechanically ventilated patients with laryngeal mask airway (LMA) insertion.

Material/Methods

A total of 60 patients who were scheduled for elective surgery under general anesthesia with LMA insertion were enrolled. After LMA insertion, the image of RIJV and RCCA were taken after applying 4 different PEEPs in a random order: 0 (P0), 5 (P5), 10 (P10), and 15 (P15) cm H₂O. The CSA, transverse and anteroposterior (AP) diameters of the RIJV, and the overlap index were measured.

Results

Compared to group P0, the overlap indexes of P10 (P=0.0032) and P15 (P<0.001) were significantly increased, but without a significant trend toward further increases in group P15. PEEP at 10 and 15 cm H₂O increased CSA, transverse and AP diameter of the RIJV in comparison to group P0 (all P<0.001). There was a statistically significant increase in CSA of the RIJV in P15 compared with P10 by 12.2% (P<0.001), but did not reach the relevant cut-off value (ΔCSA ≥15%).

Conclusions

The application of PEEP at 10 cm and 15 cm H₂O in patients receiving mechanical ventilation with LMA insertion significantly increases the size of the RIJV. However, the overlap index between the RIJV and the RCCA increased as well.

The Influence of the Univent® Endotracheal Tube on Internal Jugular Vein Cannulation

This prospective clinical investigation assessed the effect of placement of a Univent® tube on the anatomy of the internal jugular veins and the success of cannulation of the left internal jugular vein. After obtaining informed consent, 48 adult patients were enrolled. Of these, 42 patients were eligible and were divided into two groups: Univent® tube (group U, n=21) and wire enforced endotracheal tube (group C, n=21). The Univent® tube group were having a left thoracotomy. Using horizontal ultrasound scans just above the thyroid gland, the internal jugular vein was visualized and measured before and after Univent® placement. The number of needle passes necessary to cannulate the left internal jugular vein in the two groups was also compared.

Univent® tubes were associated with lateral displacement of the right carotid artery and internal jugular vein on the convex side of the Univent® tube, with compression of the right internal jugular vein by the artery, resulting in a kidney-shaped cross-section of the vein. On the left (concave side of the tube), the neck was indented, the sheath of the left carotid artery was displaced medially, and the left internal jugular vein distorted to an ellipse. There was a significant increase in the lateral diameter and a decrease in the cross-sectional area of the left internal jugular vein (t-test, P<0.05). The first attempt at cannulation of the left internal jugular vein failed significantly more often in the Univent® group (13/21 vs 5/21 in group C, Chi-square 6.22, P=0.025). Cannulation of the internal jugular vein before placement of the Univent® tube, or placement with ultrasound guidance is suggested.

Complications Associated with the Use of Supraglottic Airway Devices in Perioperative Medicine

Supraglottic airway devices are routinely used for airway maintenance in elective surgical procedures where aspiration is not a significant risk and also as rescue devices in difficult airway management. Some devices now have features mitigating risk of aspiration, such as drain tubes or compartments to manage regurgitated content. Despite this, the use of these device may be associated with various complications including aspiration. This review highlights the types and incidence of these complications. They include regurgitation and aspiration of gastric contents, compression of vascular structures, trauma, and nerve injury. The incidence of such complications is quite low, but as some carry with them a significant degree of morbidity the need to follow manufacturers' advice is underlined. The incidence of gastric content aspiration associated with the devices is estimated to be as low as 0.02% with perioperative regurgitation being significantly higher but underreported. Other serious, but extremely rare, complications include pharyngeal rupture, pneumomediastinum, mediastinitis, or arytenoid dislocation. Mild short-lasting adverse effects of the devices have significantly higher incidence than serious complications and involve postoperative sore throat, dysphagia, pain on swallowing, or hoarseness. Devices may have deleterious effect on cervical mucosa or vasculature depending on their cuff volume and pressure.

Radiographic evaluation of carotid artery compression in patients with extraglottic airway devices in place

OBJECTIVES

Extraglottic airway devices (EADs) are now commonly placed for airway management of critically ill or injured patients, particularly by emergency medical services providers in the out-of-hospital setting. Recent literature has suggested that EADs may cause decreased cerebral blood flow due to compression of the arteries of the neck by the devices' inflated cuffs.

METHODS

The authors identified a cohort of 17 patients presumed to be hemodynamically stable with EADs in place who underwent radiographic imaging of the neck. These studies were reviewed by a neuroradiologist to determine if mechanical compression of the carotid arteries was present.

RESULTS

None of the 17 cases reviewed had radiographically evident mechanical compression of the carotid artery.

CONCLUSIONS

Until further studies are performed in which cerebral perfusion is evaluated prospectively in both hemodynamically stable and unstable human subjects, there is insufficicent evidence to recommend against the use of extraglottic airways in the emergency setting on the basis of carotid artery compression.

Accuracy of the central landmark for catheterization of the right internal jugular vein after placement of the ProSeal laryngeal mask airway

OBJECTIVE

Catheterization of the internal jugular vein (IJV) after placement of a laryngeal mask airway (LMA) has been reported to be difficult. The purpose of this study was to evaluate the accuracy of the central landmark for catheterization of the right IJV after placement of a ProSeal LMA.

METHODS

We enrolled 80 patients (30 men and 50 women) who were scheduled to undergo surgery under general anesthesia conveyed by a size 3 ProSeal LMA. A needle pathway based on the central landmark for right IJV catheterization was simulated. Ultrasound images were obtained, which we contrasted with the simulated pathway to evaluate whether the landmark accuracy remained unchanged after placement of the ProSeal LMA. Both frequency of simulated right carotid artery (CA) puncture and overlap between the right IJV and right CA were also investigated.

RESULTS

The simulated needle pathway ran along the course of the right IJV in 60% (48/80) of subjects, and transected the CA in 31.3% (25/80) of subjects. Both events together occurred in 20% (16/80) of subjects. The central landmark had a medial bias of 6.8 mm (95% confidence interval, 5.3-8.4). In 83.8% (67/80) of subjects, the center of the right IJV was lateral to the central landmark. The possibility of overlap of the right IJV and CA was high after ProSeal LMA placement.

CONCLUSION

After placement of the ProSeal LMA, the central landmark could not offer a good success rate at the first puncture attempt. When using the central landmark to catheterize the IJV after a ProSeal LMA placement, medial deviation of the central landmark should be considered. Ultrasound guidance may be helpful in difficult cases.

A comparison of the i-gel with the LMA-Unique in non-paralysed anaesthetised adult patients

SUMMARY

This study assessed two disposable devices; the newly developed supraglottic airway device i-gel and the LMA-Unique in routine clinical practice. Eighty patients (ASA 1-3) undergoing minor routine gynaecologic surgery were randomly allocated to have an i-gel (n = 40) or LMA-Unique (n = 40) inserted. Oxygen saturation, end-tidal carbon dioxide, tidal volume and peak airway pressure were recorded, as well as time of insertion, airway leak pressure, postoperative sore-throat, dysphonia and dysphagia for each device. Time of insertion was comparable with the i-gel and LMA-Unique. There was no failure in the i-gel group and one failure in the LMA-Unique group. Ventilation and oxygenation were similar between devices. Mean airway pressure was comparable with both devices, whereas airway leak pressure was significantly higher (p < 0.0001) in the i-gel group (mean 29 cmH(2)O, range 24-40) compared with the LMA-Unique group (mean 18 cmH(2)O, range 6-30). Fibreoptic score of the position of the devices was significantly better in the i-gel group. Post-operative sore-throat and dysphagia were comparable with both devices. Both devices appeared to be simple alternatives to secure the airway. Significantly higher airway leak pressure suggests that the i-gel may be advantageous in this respect.

Comparison of central venous and external jugular venous pressures during repair of proximal femoral fracture

BACKGROUND

External jugular venous pressure (EJVP) is a close estimate of central venous pressure (CVP) in patients undergoing mechanical ventilation in the supine position, but the effects of spontaneous respiration and posture on this relationship are not known. In this study, we compared CVP with EJVP measurements in 36 patients undergoing repair of proximal femoral fracture breathing spontaneously in the supine or lateral positions.

METHODS

A standard general anaesthetic was administered with patients breathing spontaneously via a laryngeal mask airway and i.v. fluids administered according to an algorithm guided by CVP measurements. CVP and EJVP catheters were placed on the right side of the neck where possible.

RESULTS

In the supine position, 185 paired measurements of CVP and EJVP and 79 in the lateral position were recorded by a blinded observer during surgery. In the supine position, the mean difference between CVP and EJVP was -0.3 mm Hg (limits of agreement -2.6 to +1.9 mm Hg, 95% confidence intervals for both upper and lower limits of agreement, respectively, were -2.9 to -2.2 and +1.6 to +2.2 mm Hg). In the lateral position, the mean difference was -1.2 mm Hg (limits of agreement -5.8 to +3.8 mm Hg, 95% confidence intervals -6.8 to -4.5 and +2.7 to +4.9 mm Hg).

CONCLUSIONS

These data suggest that EJVP is an acceptable estimate of CVP in the supine position. Agreement was poor in the lateral position but was stronger for estimates of trend rather than absolute values. This could be explained by the direct effects of posture.

Early complication of pediatric central venous cannulation

We describe a case of hemothorax following central venous catheter (CVC) insertion in an infant. Presumably injury occurred as a result of perforation with the dilator. Strategies to reduce the risk of complications and possible factors influencing the unsatisfactory delay in diagnosis, including the role of 'Fixation Error', are discussed.

A comparison of the laryngeal mask airway ProSeal and the laryngeal tube airway in paralyzed anesthetized adult patients undergoing pressure-controlled ventilation

We compared the laryngeal mask airway ProSeal (PLMA) and the laryngeal tube airway (LTA), two new extraglottic airway devices, with respect to: 1) insertion success rates and times, 2) efficacy of seal, 3) ventilatory variables during pressure-controlled ventilation, 4) tidal volume in different head/neck positions, and 5) airway interventional requirements. One-hundred-twenty paralyzed anesthetized ASA physical status I and II adult patients were randomly allocated to the PLMA or LTA for airway management. A standardized anesthesia protocol was followed by two anesthesiologists experienced with both devices. The criteria for an effective airway included a minimal expired tidal volume of 6 mL/kg during pressure-controlled ventilation at 17 cm H(2)O with no oropharyngeal leak or gastric insufflation. First attempt success rates at achieving an effective airway were similar (PLMA: 85%; LTA: 87%), but after 3 attempts, success was more frequent for the PLMA (100% versus 92%, P = 0.02). Effective airway time was similar. Oropharyngeal leak pressure was larger for PLMA at 50% maximal recommended cuff volume (29 +/- 7 versus 21 +/- 6 cm H(2)O, P < 0.0001), but was similar at the maximal recommended cuff volume (33 +/- 7 versus 31 +/- 8 cm H(2)O). Tidal volumes (614 +/- 173 versus 456 +/- 207 mL, P < 0.0001) were larger and ETCO(2) (33 +/- 9 versus 40 +/- 11 mm Hg, P = 0.0001) lower for the PLMA. The number of airway interventions was significantly less frequent for the PLMA. Airway obstruction was more common with the LTA. When comparing mean tidal volumes in different head/neck positions, the quality of airway was unchanged in 56 of 60 patients (93%) with the PLMA and 42 of 55 (76%) with the LTA (P = 0.01). The PLMA offers advantages over the LTA in most technical aspects of airway management in paralyzed patients undergoing pressure-controlled ventilation.

IMPLICATIONS

The laryngeal mask airway ProSeal offers advantages over the laryngeal tube airway in most technical aspects of airway management in paralyzed patients undergoing pressure-controlled ventilation.

Emergence characteristics and postoperative laryngopharyngeal morbidity with the laryngeal mask airway: a comparison of high versus low initial cuff volume

In this study we tested the hypothesis that the initial cuff volume of the laryngeal mask airway influences emergence characteristics and postoperative laryngopharyngeal morbidity. One hundred and sixty adult patients undergoing minor surgery were randomly assigned for airway management with the laryngeal mask airway with either a fully inflated cuff (LMA-High) or a semi-inflated cuff (LMA-Low). Anaesthesia was with propofol, nitrous oxide, oxygen and isoflurane. Following insertion, the cuff was inflated with either 15 or 30 ml for the size 4 (females) and 20 or 40 ml for the size 5 (males). At the end of surgery, a blinded observer documented the presence or absence of adverse airway events (hypoxia, hypercapnea, coughing, retching, regurgitation/vomiting, airway obstruction, hypoventilation, hiccupping, biting, body movement or shivering) during every 1 min epoch and cardiorespiratory variables (heart rate, mean blood pressure, arterial oxygen saturation, end-tidal carbon dioxide and respiratory rate) every 5 min until the patient was awake and the laryngeal mask airway removed. Patients were interviewed about pharyngolaryngeal morbidity (sore throat, dysphonia and dysphagia) immediately before leaving the postanaesthesia care unit and 18-24 h following surgery. Analysis by epoch showed more partial airway obstruction in the LMA-High group, but analysis by patient numbers revealed no difference. Heart rate was slightly higher in the LMA-High group upon arrival in the postanaesthesia care unit, but otherwise there were no differences in cardiorespiratory responses. Sore throat and dysphagia were more common in the LMA-High group. We conclude that, in general, emergence characteristics with the laryngeal mask airway are not influenced by the volume of air used to inflate the cuff, but that postoperative sore throat and dysphagia are more likely at high initial cuff volumes.

A comparison of the disposable versus the reusable laryngeal mask airway in paralyzed adult patients

A disposable (polyvinyl chloride) laryngeal mask airway (LMA) with dimensions identical to, but physical properties different from (stiffer tube/thicker cuff), the reusable (silicone) LMA has recently become available. We performed a randomized, cross-over study of 60 paralyzed, anesthetized patients to test the hypothesis that the use of these devices was different in terms of ease of insertion, airway sealing pressure, fiberoptic position, and changes in intracuff pressure during N2O anesthesia. We also tested the hypothesis that the airway sealing pressure of the LMA is suboptimal if the cuff is inflated to a high intracuff pressure. Both the devices were inserted into each patient in random order, and their performance was assessed at two intracuff pressures (60 and 180 cm H2O) by a blind observer. Subsequently, intracuff pressures were measured during N2O anesthesia for the second device. Ease of insertion was similar: there was no difference in first attempt success rates (97% vs 98%) and insertion times (15 vs 13 s) for the disposable and reusable LMA, respectively. There were no differences in airway sealing pressure or fiberoptic position. Airway sealing pressure was significantly higher at 60 cm H2O intracuff pressure compared with the airway sealing pressure at 180 cm H2O for both devices (P < 0.02). During N2O anesthesia, the intracuff pressure remained stable for the disposable LMA but increased significantly for the reusable LMA. We conclude that the disposable and reusable LMAs perform similarly in paralyzed adult patients, but that the disposable LMA has more stable intracuff pressures during N2O anesthesia. Inflation of the LMA to high intracuff pressures produces a suboptimal seal.

IMPLICATIONS

This randomized, single-blind, within-patient study of 60 adult patients shows that the disposable (polyvinyl chloride) and reusable (silicone) laryngeal mask airways perform similarly, but that the disposable laryngeal mask airway has more stable intracuff pressures during N2O anesthesia. Inflation of either device to high intracuff pressures produces a suboptimal seal.

An evaluation of the factors influencing selection of the optimal size of laryngeal mask airway in normal adults

The purpose of this randomised single blinded study was to determine the optimal size of laryngeal mask airway in the normal adult population, to test the validity of the current selection criteria and to determine if any externally measured anatomical variable correlated with optimal size. In each of 30 apnoeic anaesthetised adults weighting less than 100 kg, size 3, 4 and 5 laryngeal mask airways were inserted in random order by a skilled user and the cuff inflated to a standard pressure (60 cm H2O). Optimal size was based on four criteria in order of priority: number of attempts at placement, oropharyngeal leak pressure, fiberoptic score and percentage of vocal cords seen. The size 5 laryngeal mask airway was optimal in 19/30 and the size 4 in 11/30. In no patient was the size 3 the optimal fit. Oropharyngeal leak pressure was significantly higher for each progressively large size and the fiberoptic view was significantly better for the size 4 and size 5. There was no significant predictive value in any externally measured anatomical variable, but height was the most useful. The best current selection strategy was to choose a size 5 for males and size 4 for females. Potentially useful new strategies may be to use the size 5 in all adults, or a size 5 > or = 165 cm in height and size 4 for < 165 cm. We conclude that predicting the optimal size of laryngeal mask airway for individual adult patients is complex. The best size selection strategies involve use of the size 4 and 5 laryngeal mask airways in adults.

The laryngeal mask airway reduces blood flow in the common carotid artery bulb

PURPOSE

The introduction of the laryngeal mask airway (LMA) has had a major impact on anaesthetic practice in the last ten years. Previous authors have demonstrated pressures equivalent to mean arterial blood pressure within the cuff of the LMA. This study examined the effects of cuff inflation on the cross sectional area, flow and velocity of blood flow at the level of the carotid sinus.

METHODS

Seventeen patients scheduled to have LMAs inserted as part of routine anaesthetic management were recruited into the study. Measurements of the common carotid artery bulb area, peak velocity and blood flow were performed upon LMA cuff inflation and deflation using a 5 MHz pulse wave Doppler probe.

RESULTS

Deflation of the cuff resulted in an increase in the cross sectional area (from 0.58 +/- 0.05 to 0.64 +/- 0.04 cm2; P < 0.005), an increase in blood flow (from 65.6 +/- 5.6 to 73.9 +/- 5.6 cm3.sec-1; P < 0.05) and a slight but non significant increase in velocity of blood flow.

CONCLUSION

This study demonstrates that inflation of the cuff on the LMA results in a decrease in carotid bulb cross sectional area which results in a decrease in blood flow.