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

Medication-Facilitated Advanced Airway Management with First-Line Use of a Supraglottic Device - A One-Year Quality Assurance Review

INTRODUCTION

Airway management is a controversial topic in modern Emergency Medical Services (EMS) systems. Among many concerns regarding endotracheal intubation (ETI), unrecognized esophageal intubation and observations of unfavorable neurologic outcomes in some studies raise the question of whether alternative airway techniques should be first-line in EMS airway management protocols. Supraglottic airway devices (SADs) are simpler to use, provide reliable oxygenation and ventilation, and may thus be an alternative first-line airway device for paramedics. In 2019, Alachua County Fire Rescue (ACFR; Alachua, Florida USA) introduced a novel protocol for advanced airway management emphasizing first-line use of a second-generation SAD (i-gel) for patients requiring medication-facilitated airway management (referred to as "rapid sequence airway" [RSA] protocol).

STUDY OBJECTIVE

This was a one-year quality assurance review of care provided under the RSA protocol looking at compliance and first-pass success rate of first-line SAD use.

METHODS

Records were obtained from the agency's electronic medical record (EMR), searching for the use of the RSA protocol, advanced airway devices, or either ketamine or rocuronium. If available, hospital follow-up data regarding patient condition and emergency department (ED) airway exchange were obtained.

RESULTS

During the first year, 33 advanced airway attempts were made under the protocol by 23 paramedics. Overall, compliance with the airway device sequence as specified in the protocol was 72.7%. When ETI was non-compliantly used as first-line airway device, the first-pass success rate was 44.4% compared to 87.5% with adherence to first-line SAD use. All prehospital SADs were exchanged in the ED in a delayed fashion and almost exclusively per physician preference alone. In no case was the SAD exchanged for suspected dislodgement evidenced by lack of capnography.

CONCLUSION

First-line use of a SAD was associated with a high first-pass attempt success rate in a real-life cohort of prehospital advanced airway encounters. No SAD required emergent exchange upon hospital arrival.

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.

Severe bradycardia caused by the deviation of the laryngeal mask airway Supreme: A case report

RATIONALE

Classic laryngeal mask airway (LMA) has long been used for airway management. The LMA Supreme is a modified single-use version of the LMA Proseal, but it still remains some deficits such as the instable positioning that lead to easily sliding and the mask bowl full of air might lead to the reduced blood flow of the internal carotid artery. The carotid sinus is a baroreceptor that responds to the stretching of the arterial wall. Manual pressure of the carotid artery at the upper margin of the sternocleidomastoid muscle provoked bradycardia and hypotension.

PATIENT CONCERNS

A previously fit and well 42-year-old woman presented with breast fibroma on the left side. No other disease history could be recorded. Her family history was negative for neuromuscular and autoimmune disease.

DIAGNOSES

The patient suffered from a severe bradycardia and hypotension when the LMA showed a shift. We presented with a hypothetical that the dislocated LMA may cause carotid sinus syndrome (CSS).

INTERVENTIONS

The patient's heart rate (HR) gradually rosed up as soon as the LMA adjusted back to the normal position.

OUTCOMES

The patient was comfortable in the post anesthesia care unit (PACU) and had no adverse sequelae.

LESSONS

The position of LMA Supreme should be confirmed throughout the surgery especially for the ones who has changed the position and the head was covered by surgical drapes.

Impact of the laryngeal tube as supraglottic airway device on blood flow of the internal carotid artery in patients undergoing general anaesthesia

INTRODUCTION

Laryngeal tubes (LT) are supraglottic airway devices routinely used in emergency airway management. During cardiac arrest in a swine model, the carotid artery blood flow is reduced after insertion of a LT. A compression of the internal carotid (ICA) artery by the inflated cuff was shown. Up to now there is no information if the LT has similar effects in humans with possible negative implications for use of the LT in case of cardiac arrest.

OBJECTIVE

We hypothesized that the use of a LT in humans significantly reduces the blood flow in the ICA compared facemask ventilation. A significant reduction was defined as a 25% reduction from baseline values.

MATERIAL AND METHODS

After induction of general anaesthesia and reaching a haemodynamic steady state (stable heart rate >50/min and mean arterial pressure >60 mmHg), blood flow within the ICA was measured via doppler sonography during pressure-controlled ventilation with facemask-, laryngeal tube- and laryngeal mask.

RESULTS

We found no differences in the carotid blood flow. Neither between the facemask ventilation (right side 419 ± 159 ml min^-1, left side 355 ± 120 ml min^-1) and the laryngeal tube ventilation (right side 400 ± 131 ml min^-1, left side 384 ± 124 ml min^-1. p = 0.86 and p = 0.12), nor the facemask-ventilation and the laryngeal mask ventilation (right ICA 415 ± 150 ml min^-1, left ICA 485 ± 274 ml min^-1, p = 0.49 and 0.26).

CONCLUSIONS

In humans the LT does not impair blood flow of the internal carotid artery during ventilation in general anaesthesia. Further studies are needed to confirm our findings under the conditions of cardiac arrest.

Effect of endotracheal intubation and supraglottic airway device placement during cardiopulmonary resuscitation on carotid blood flow over resuscitation time: An experimental porcine cardiac arrest study

BACKGROUND

Supraglottic airway devices (SGDs) are widely used during the resuscitation of out-of-hospital cardiac arrest (OHCA). The effect of SGDs on carotid blood flow (CBF) as resuscitation time passes is controversial. We assessed the effects of endotracheal intubation (ETI) and 3 types of SGD placement on CBF over time in prolonged resuscitation through an experimental porcine cardiac arrest study.

METHODS

We conducted a randomized crossover study using 12 female pigs. After 4 min of untreated ventricular fibrillation, 3 pairs of ETI for 3 min and each type of SGD placement, including Combitube, I-gel, and laryngeal mask airway, for 3 min were conducted. The order of the 3 pairs of ETI and SGD were randomly assigned for each pig. We measured physiological parameters including CBF and mean arterial pressure (MAP). We compared CBF and MAP between the last 1 min of the insertion period for each of the 3 types of SGD and the preceding ETI period. Trends of CBF and MAP according to ETI and SGD transition were also plotted during the prolonged resuscitation duration.

RESULTS

CBF decreased after inserting I-gel and Combitube compared to ETI (mean difference (95% CI): -685 ml (-1052 to -318) for Combitube, -369 ml (-623 to -114) for I-gel). MAP subsequently decreased after transitioning airway devices as resuscitation was prolonged, regardless of the device type. The mean CBF during the transition from ETI to SGD decreased by -480 ml (95% CI: -675 to -286), but the decrease in CBF during the transition from SGD to ETI was only -4 ml (95% CI: -182 to 175).

CONCLUSION

SGD placement was associated with decreased carotid blood flow during cardiopulmonary resuscitation in an experimental porcine model. As time passed during prolonged resuscitation, reduction in CBF was aggravated after the transition to SGD placement compared to the reduction after the transition to ETI. This study was approved by the study institution IACUC 16-0140-S1A0.

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.

Laryngeal mask airway may result in false negative imaging for carotid medialization: A case report

Chromosome 22q11.2 microdeletions result in multiple congenital abnormalities, including an increased risk of carotid medialization, which is an important consideration for preoperative planning in children with velopharyngeal insufficiency. Preoperative imaging of the neck vasculature is recommended. Here we describe a case in which a child had negative imaging studies despite the presence of a medialized carotid artery on physical examination, likely secondary to the supraglottic airway use during sedated imaging, which displaced the carotid laterally. The type of airway used should be a consideration for children undergoing sedated imaging prior to pharyngeal procedures.

Association of advanced airway device with chest compression fraction during out-of-hospital cardiopulmonary arrest

BACKGROUND

Select Emergency Medical Services (EMS) practitioners substitute endotracheal intubation (ETI) with supraglottic airway (SGA) insertion to minimize CPR chest compression interruptions, but the resulting effects upon chest compression fraction (CCF) are unknown. We sought to determine the differences in CCF between adult out-of-hospital cardiac arrest (OHCA) receiving ETI and those receiving SGA.

METHODS

We studied adult, non-traumatic OHCA patients enrolled in the Resuscitation Outcomes Consortium (ROC) Prehospital Resuscitation using an Impedance valve and an Early vs. Delayed analysis (PRIMED) trial. Chest compressions were measured using compression or thoracic impedance sensors. We limited the analysis to those receiving ETI or SGA (Combitube, King Laryngeal Tube, or Laryngeal Mask Airway) and >2min of chest compression data before and after airway insertion. We compared CCF between ETI and SGA before and after airway insertion, adjusting for age, sex, witnessed arrest, bystander CPR, shockable initial rhythm, public location, PRIMED trial arm, and regional ROC center. We also compared the change in CCF for each airway technique.

RESULTS

Of 14,955 patients enrolled in the ROC PRIMED trial, we analyzed 2767 cases, including 2051 ETI, 671 SGA, and 45 both. Among subjects in this investigation the mean age was 66.4 years with a male predominace, 46% with witnessed event, 37% receiving bystander CPR, and 22% presenting with an initially shockable rhythm. Pre- and post-airway CCF was higher for SGA than ETI (SGA pre-airway CCF 73.2% [95%CI: 71.6-74.7%] vs. ETI 70.6% [95%CI: 69.7-71.5%]; post-airway 76.7% [95%CI: 75.2-78.1%] vs. 72.4% [95%CI: 71.5-73.3%]). After adjusting for potential confounders, these significant changes persisted (pre-airway difference 2.2% favoring SGA, p-value=0.046; post-airway 3.4% favoring SGA, p=0.001).

CONCLUSION

In patients with OHCA, we detected a slightly higher rate of CCF in patients for whom a SGA was inserted, both before and after insertion. However, the actual differences were so small, that in the context of this observational, secondary analysis, it is unclear if this represents a clinically significant difference.

Impact of laryngeal tube use on chest compression fraction during out-of-hospital cardiac arrest. A prospective alternate month study

AIM

Supraglottic devices are thought to allow efficient ventilation and continuous chest compressions during cardiac arrest. Therefore, the use of supraglottic devices could increase the chest compression fraction (CCF), a critical determinant of patient survival. The aim of this study was to assess the CCF in out-of-hospital cardiac arrest (OHCA) patients ventilated with a supraglottic device.

METHODS

We conducted an open prospective multicenter study with temporal clusters. OHCA patients treated by emergency nurses received either intermittent chest compressions with bag-valve mask ventilations (30:2 rhythm; BVM group); or continuous chest compressions with asynchronous ventilations by laryngeal tube (LT group). The primary endpoint was the CCF assessed using an accelerometer connected to the defibrillator. We also investigated the ease of use of the laryngeal tube.

RESULTS

Eighty-two patients were included (41 in each group); 68% were male and the median age was 68 (54-80) years. Patients and cardiac arrest characteristics did not differ between groups. The CCF was 75% (68-79%) in the LT group and 59% (51-68%) in the BVM group (p<0.01). LT insertion failed in nine out of 40 cases (23%). The median time of LT insertion was 26s (11-56 s). CCF was significantly lower when LT insertion failed (58% (48-74%) vs. 76% (72-80%) when LT insertion succeeded; p=0.01).

CONCLUSION

The use of the LT during OHCA increases the CCF when compared to standard BVM ventilation. However, the impact of LT use on mortality remains unclear.

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.

The effect of cuff pressure on postoperative sore throat after Cobra perilaryngeal airway

PURPOSE

The cuff volume of the Cobra perilaryngeal airway (CobraPLA) is larger than that of other alternative airway devices and makes it difficult to predict the effect of cuff pressure on the perilaryngeal mucosa. We tested the hypothesis that adjustment of the cuff pressure of the CobraPLA could reduce the incidence of postoperative sore throat (POST).

METHODS

After induction of general anesthesia and insertion of the CobraPLA by standardized method, the cuff pressure was set to 60 cmH(2)O (group C, n = 87) or adjusted to minimal seal-up pressure +5 cmH(2)O (group A, n = 87). The frequency and severity (0, none; 1, mild; 2, moderate; 3, severe) of throat soreness, pain, discomfort, and adverse effects were evaluated 1 and 24 h after removal of the CobraPLA.

RESULTS

Incidence of moderate POST in group C was higher than that in group A (11% vs. 2%, P = 0.021) whereas the overall POST incidence was not different between the two groups (31% vs. 20%, P = 0.092). The inflated air volume of group A was different from that of group C (41 vs. 50 ml, P = 0.009).

CONCLUSIONS

Adjustment of cuff pressure reduces the incidence of moderate POST after use of the CobraPLA.

Randomised comparison of the Classic Laryngeal Mask Airway with the Cobra Perilaryngeal Airway during anaesthesia in spontaneously breathing adult patients

We tested the hypothesis that the Cobra Perilaryngeal Airway (PLA) with its high volume low-pressure cuff would provide superior airway leakage pressure compared with the Classic Laryngeal Mask Airway (LMA) in spontaneously breathing adult patients. Ninety consecutive adult patients were randomly allocated to receive one of these two supralaryngeal devices. The airway leakage pressure was higher for the PLA compared with the LMA (22 +/- 9 cmH2O vs. 18 +/- 6 cmH2O; P < 0.05). The mean airway device intracuff pressure was lower for the PLA compared to the LMA (36.1 +/- 15.2 mmHg vs. 86.3 +/- 25.3 mmHg P < 0.0001). The time required to achieve successful insertion was greater for the PLA compared with the LMA (39 +/- 21 seconds vs. 27 +/- 10 seconds; P < 0.005). The number of attempts required to achieve successful insertion and the incidence of postoperative complications were similar in both groups. The findings suggest that the PLA provides a superior airway seal at a lower intracuff pressure compared to the LMA. However the time for successful insertion may be increased.

Effect of high laryngeal mask airway intracuff pressure on the laryngopharyngeal mucosa of dogs

OBJECTIVES

To evaluate the effect of increased of laryngeal mask airway (LMA) intracuff pressures on the laryngopharyngeal mucosa.

STUDY DESIGN

Animal model.

METHODS

Sixteen mixed-breed dogs were randomly allocated to two groups, G1 (intracuff volume, 30 mL; n = 8) and G2 (intracuff volume, 54 mL; n = 8), to produce, respectively, high or very high intracuff pressures. Anesthesia was induced and maintained with pentobarbital. Intracuff pressures were measured immediately after insertion and inflation of a No. 4 laryngeal mask airway (LMA) and 30, 60, 90, and 120 minutes thereafter. The dogs were euthanized, and biopsy specimens from eight predetermined areas of the laryngopharynx in contact with LMA cuff were collected for light microscopic (LM) and scanning electron microscopic (SEM) examination.

RESULTS

Initial LMA cuff inflation in G1 and G2 resulted in intracuff pressures of 119 mm Hg +/- 4 mm Hg and 235 mm Hg +/- 13 mm Hg, respectively. Over a 2-hour period, the intracuff pressure decreased significantly in G1 (P < .001) and G2 (P < .01), and there was a significant difference between the groups over time (P < .001). The LM study of laryngopharyngeal mucosa in both groups showed mild congestion in the subepithelial layer. There were no differences between the groups (P > .10) or among the areas sampled (P > .10). In some areas of G2, the SEM study showed epithelial desquamation that was more intense than that in G1.

CONCLUSIONS

The increase in LMA intracuff pressure caused only mild alterations in the laryngopharyngeal mucosa of the dog.

Anesthesia for carotid endarterectomy

Patients presenting for carotid endarterectomy provide anesthesiologists with many challenges. These include optimization of cerebrovascular hemodynamics and oxygen balance, as well as minimizing myocardial risk. Fiscal pressures have encouraged the development of clinical pathways in many centers, with a remarkable trend towards decreased intensive care unit utilization and length of hospital stay. Anesthetic and surgical practices vary widely, but outcomes in these high-risk patients are usually excellent despite these differences. The potential for expanded indications for carotid endarterectomy and development of percutaneous treatment for carotid stenosis will provide neurovascular anesthesiologists with additional incentives to refine the anesthetic management of these patients.