Rapid sequence induction: a national survey of practice

Anaesthesia protocol evaluation of the videolaryngoscopy with the McGrath MAC and direct laryngoscopy for tracheal intubation in 1000 patients undergoing rapid sequence induction: the randomised multicentre LARA trial study protocol

INTRODUCTION

Rapid sequence induction of anaesthesia is indicated in patients with an increased risk of pulmonary aspiration. The main objective of the technique is to reduce the critical time period between loss of airway protective reflexes and rapid inflation of the cuff of the endotracheal tube to minimise the chance of aspiration of gastric contents. The COVID-19 pandemic has reinforced the importance of first-pass intubation success to ensure patient and healthcare worker safety. The aim of this study is to compare the first-pass intubation success rate (FPS) using the videolaryngoscopy compared with conventional direct laryngoscopy in surgical patients with a high risk of pulmonary aspiration.

METHODS AND ANALYSIS

The LARA trial is a multicentre, patient-blinded, randomised controlled trial. Consecutive patients requiring tracheal intubation are randomly allocated to either the McGrath MAC videolaryngoscope or direct laryngoscopy using the Macintosh laryngoscope. The expected rate of FPS is 92% in the McGrath group and 82% in the Macintosh group. Each group must include a total of 500 patients to achieve 90% power for detecting a difference at the 5% significance level. Successful intubation with the FPS is the primary endpoint. The secondary endpoints are the time to intubation, the number of intubation attempts, the necessity of airway management alternatives, the visualisation of the glottis using the Cormack and Lehane Score and the Percentage Of Glottic Opening Score and definite adverse events.

ETHICS AND DISSEMINATION

The project is approved by the local ethics committee of the Medical Association of the Rhineland Palatine state (registration number: 2020-15502) and medical ethics committee of the University of Freiburg (registration number: 21-1303). The results of this study will be made available in form of manuscripts for publication and presentations at national and international meetings.

TRIAL REGISTRATION

NCT04794764.

Rapid sequence induction/intubation controversies

Backgrounds:

Since its first definition and publication on 1970, Rapid Sequence Induction / Intubation (RSI) technique has been accepted globally as the “standard” for doing rapid intubation after induction of anesthesia for patients with high risk of aspiration, especially in emergency situation. However, this technique is not so much a “standard” as there are numerous variations on its practice based on national surveys. Anesthesia providers have their own opinions on the practice of RSI components which need to be discussed to assess their advantages and disadvantages, while there has been no review article which discussed these controversies in the last ten years.

Objectives:

To review the technique differences within RSI protocols.

Methods:

Online databases were searched, including MEDLINE and COCHRANE for each step in the original RSI protocol using keywords such as: “rapid sequence induction” or “rapid sequence intubation” or “RSI” and “controversies” or “head position” or “cricoid pressure” or “neuromuscular blocking agent” or “NMBA” or positive pressure ventilation” or “PPV”; and so on. Articles were then sorted out based on relevancy.

Results and conclusion:

Supported by new evidence, RSI practices may differ in: the positioning of patient, choices of induction agent, application of cricoid pressure, choices of neuromuscular blocking agent, and the use of positive pressure ventilation. A more updated and standardized guideline should be established by referring and evaluating to these controversies.

Rapid sequence induction: where did the consensus go?

Background

Rapid Sequence Induction (RSI) was introduced to minimise the risk of aspiration of gastric contents during emergency tracheal intubation. It consisted of induction with the use of thiopentone and suxamethonium with the application of cricoid pressure.

This narrative review describes how traditional RSI has been modified in the UK and elsewhere, aiming to deliver safe and effective emergency anaesthesia outside the operating room environment. Most of the key aspects of traditional RSI – training, technique, drugs and equipment have been challenged and often significantly changed since the procedure was first described. Alterations have been made to improve the safety and quality of the intervention while retaining the principles of rapidly securing a definitive airway and avoiding gastric aspiration. RSI is no longer achieved by an anaesthetist alone and can be delivered safely in a variety of settings, including in the pre-hospital environment.

Conclusion

The conduct of RSI in current emergency practice is far removed from the original descriptions of the procedure. Despite this, the principles – rapid delivery of a definitive airway and avoiding aspiration, are still highly relevant and the indications for RSI remain relatively unchanged.

Rapid sequence induction: An international survey

BACKGROUND

Rapid sequence induction (RSI) is a standard procedure, which should be implemented in all patients with a risk of aspiration/regurgitation during anaesthesia induction.

OBJECTIVE

The primary aim was to evaluate clinical practice in RSI, both in adult and paediatric populations.

DESIGN

Online survey.

SETTINGS

A total of 56 countries.

PARTICIPANTS

Members of the European Society of Anaesthesiology.

MAIN OUTCOME MEASURES

The aim was to identify and describe the actual clinical practice of RSI related to general anaesthesia.

RESULTS

From the 1921 respondents, 76.5% (n=1469) were qualified anaesthesiologists. When anaesthetising adults, the majority (61.7%, n=1081) of the respondents preoxygenated patients with 100% O₂ for 3 min and 65.9% (n=1155) administered opioids during RSI. The Sellick manoeuvre was used by 38.5% (n=675) and was not used by 37.4% (n=656) of respondents. First-line medications for a haemodynamically stable adult patient were propofol (90.6%, n=1571) and suxamethonium (56.0%, n=932). Manual ventilation (inspiratory pressure <12 cmH₂O) was used in 35.5% (n=622) of respondents. In the majority of paediatric patients, 3 min of preoxygenation (56.6%, n=817) and opioids (54.9%, n=797) were administered. The Sellick manoeuvre and manual ventilation (inspiratory pressure <12 cmH₂O) in children were used by 23.5% (n=340) and 35.9% (n=517) of respondents, respectively. First-line induction drugs for a haemodynamically stable child were propofol (82.8%, n=1153) and rocuronium (54.7%, n=741).

CONCLUSION

We found significant heterogeneity in the daily clinical practice of RSI. For patient safety, our findings emphasise the need for international RSI guidelines.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03694860

Assessment of the benefits of head-up preoxygenation using near-infrared spectroscopy with pulse oximetry in a swine model

Compared with supine positioning, head-up positioning improves preoxygenation and prolongs the time to oxygen desaturation. We reevaluated benefits of head-up positioning using near-infrared spectroscopy (NIRS) with pulse oximetry in a pig model. Six pigs (mean ± SD weight: 25.3 ± 0.6 kg) were anesthetized with isoflurane and evaluated in four positions-supine, head-up, head-down, head-up to supine-just before apnea (positions' order after "supine" was randomized). In each position, after 5 min of preoxygenation with 100% oxygen, apnea was induced and the time to SpO2 < 70% measured. Hemodynamic and blood-gas variables and the cerebral tissue oxygenation index (TOI) were evaluated using NIRS and recorded. Hypovolemia was induced by collecting 600 mL blood. Apnea experiment was performed again in each position. The times (seconds) ± SD to SpO2 < 70% were 108 ± 13 (supine), 138 ± 15 (head-up; P < 0.0001 vs all other positions); 101 ± 12 (head-down) and 106 ± 15 (head-up to supine) during normovolemia, and 110 ± 29, 120 ± 7 (not significant vs all other positions), 101 ± 16, and 106 ± 11, respectively, during hypovolemia. Although the TOI was not associated with the positions during normovolemia, the head-up position during hypovolemia decreased TOI from 62% ± 6% (supine) to 50% ± 9% (head-up; P = 0.0019) before preoxygenation, and it remained low during apnea. The head-up position improves preoxygenation, but repositioning to supine negates the benefits. Head-up positioning during evident hypovolemia should be avoided because the cerebral oxygenation could decrease.

Review of evidences for management of rapid sequence spinal anesthesia for category one cesarean section, in resource limiting setting

BACKGROUND

Globally obstetric anesthesia is being done under spinal and epidural than general anesthesia (GA) for most caesarean sections (CSs). This is because GA is associated with failed endotracheal intubation and aspiration of gastric contents. Eventhough general anesthesia is the fastest method for anesthetizing a category 1 cesarean section, it is associated with increased maternal mortality and morbidity. Spinal anesthesia is the preferred regional technique for cesarean section but failure sometimes occurs. To minimize the time factor of spinal anesthesia as well as to avoid the side effects of general anesthesia 'rapid sequence spinal '(RSS) has developed as a novel approach in cases of category one cesarean sections.

METHODS

The study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Search engines like PubMed through HINARI, Cochrane database and Google Scholars were used to find high-level evidences that help to draw appropriate conclusions.

DISCUSSION

Neuraxial anesthetic techniques have several advantages which include low risk of aspiration and failed intubation, avoidance of central nervous system (CNS) and respiratory depressant drugs, the ability to maintain a wakeful state of mother enjoying the experience of delivery of baby and also lower incidence of blood loss. 'Rapid sequence spinal' described to minimize anesthetic time. This consists of a no-touch spinal technique, consideration of omission of the spinal opioid, limiting spinal attempts, allowing the start of surgery before full establishment of the spinal block, and being prepared for conversion to general anesthesia if there are delays or problems. To do rapid sequence spinal anesthesia safely and timely, cooperative work is mandatory with good team relation for those simultaneous and necessary tasks.

CONCLUSION

The choice of anesthetic in Cesarean section has long been recognized as one of prime importance, because there are two lives to safeguard instead of one. A balance must be struck between the anesthetic dictated by the general condition of the mother and that suited to the needs of the fetal respiratory system.

Audit on Current Practice of Rapid Sequence Induction and Intubation of Anesthesia in the University of Gondar Hospital, Northwest Ethiopia, 2018

Background

In patients who are liable to the risk of pulmonary aspiration, airway control is the primary and first concern for the anesthetists both in emergency and elective surgical procedures. Rapid sequence induction is universally required in any occasion of emergent endotracheal intubation needed for unfasted patients or patients' fasting status is unknown.

Methods

institutional-based prospective observational study was conducted from December 2017 to January 2018 in all elective and emergency adult or pediatric patients with a risk of pulmonary aspiration who were operated under general anesthesia with rapid sequence induction and intubation during the audit period.

Result

A total of 35 patients were operated during the study period. Of these, 31 (88.57%) patients were adults and 4 (11.43%) patients were pediatrics. Most of the patients were emergency (29 (82.857%)), and the rest were elective (6 (17.142%)).

Conclusion

Most anesthetists were good at preparing all available monitoring and drugs, making sure that IV line is well-functioning, preparing suction with a suction machine, preoxygenation, application of cricoid pressure, and checking the position of the ETT after intubation was performed. Preparing difficult airway equipment during planning of rapid sequence induction and intubation, giving roles and told to proceed their assigned role for the team, attempt to ventilate with a small tidal volume, and routine use of bougie or stylet to increase the chance of success of intubation needed improvement.

An analysis of emergency tracheal intubations in critically ill patients by critical care trainees

Introduction

We evaluated intensive care medicine trainees' practice of emergency intubations in the United Kingdom.

Methods

Retrospective analysis of 881 in-hospital emergency intubations over a three-year period using an online trainee logbook.

Results

Emergency intubations out-of-hours were less frequent than in-hours, both on weekdays and weekends. Complications occurred in 9% of cases, with no association with time of day/day of week (p = 0.860). Complications were associated with higher Cormack and Lehane grades (p=0.004) and number of intubation attempts (p < 0.001), but not American Society of Anesthesiologist grade. Capnography usage was ≥99% in all locations except in wards (85%; p = 0.001). Ward patients were the oldest (p < 0.001), had higher American Society of Anesthesiologist grades (p < 0.001) and lowest Glasgow Coma Scale (p < 0.001).

Conclusions

Complications of intubations are associated with higher Cormack and Lehane grades and number of attempts, but not time of day/day of week. The uptake of capnography is reassuring, although there is scope for improvement on the ward.

Collective Review of the Status of Rapid Sequence Intubation Drugs of Choice in Trauma in Low- and Middle-Income Settings (Prehospital, Emergency Department and Operating Room Setting)

INTRODUCTION

Establishing a definitive airway in order to ensure adequate ventilation and oxygenation is an important aspect of resuscitation of the polytrauma patient .

AIM

To review the relevant literature that compares the different drugs used for rapid sequence intubation (RSI) of trauma patients, specifically reviewing: premedication, induction agents and neuromuscular blocking agents across the prehospital, emergency department and operating room setting, and to present the best practices based on the reviewed evidence.

METHOD

A literature review of rapid sequence intubation in the trauma population was carried out, specifically comparison of the drugs used (induction agent, neuromuscular blocking drugs and adjuncts).

DISCUSSION

Studies involving the comparison of drugs used in RSI in, specifically, the trauma patient are sparse. The majority of studies have compared induction agents, etomidate, ketamine and propofol, as well as the neuromuscular blocking agents, succinylcholine and rocuronium.

CONCLUSION

There currently exists great variation in the practice of RSI; however, in trauma the RSI armamentarium is limited to agents that maintain hemodynamic stability, provide adequate intubating conditions in the shortest time period and do not have detrimental effects on cerebral perfusion pressure. Further, multicenter randomized controlled studies to confirm the benefits of the currently used agents in trauma are required.

Emergency induction of anaesthesia in the prehospital setting: a review of the anaesthetic induction agents

The standard of prehospital care is improving in many trauma systems around the world. For patients surviving the primary injury, the optimal prehospital interven tions remain debatable. Current evidence suggests that patients with severe head injury may benefit from advanced airway management, most commonly per formed by rapid sequence induction of anaesthesia and orotracheal intubation. The ‘best choice’ induction agent remains unclear, and choice seems to depend on local preferences and the skill mix of the prehospital care team. In this review we look at the recent evidence for selected hypnotic agents.

Resuscitation Prior to Emergency Endotracheal Intubation: Results of a National Survey

Introduction

Respiratory failure is a common problem in emergency medicine (EM) and critical care medicine (CCM). However, little is known about the resuscitation of critically ill patients prior to emergency endotracheal intubation (EETI). Our aim was to describe the resuscitation practices of EM and CCM physicians prior to EETI.

Methods

A cross-sectional survey was developed and tested for content validity and retest reliability by members of the Canadian Critical Care Trials Group. The questionnaire was distributed to all EM and CCM physician members of three national organizations. Using three clinical scenarios (trauma, pneumonia, congestive heart failure), we assessed physician preferences for use and types of fluid and vasopressor medication in pre-EETI resuscitation of critically ill patients.

Results

In total, 1,758 physicians were surveyed (response rate 50.2%, 882/1,758). Overall, physicians would perform pre-EETI resuscitation using either fluids or vasopressors in 54% (1,193/2,203) of cases. Most physicians would “always/often” administer intravenous fluid pre-EETI in the three clinical scenarios (81%, 1,484/1,830). Crystalloids were the most common fluid physicians would “always/often” administer in congestive heart failure (EM 43%; CCM 44%), pneumonia (EM 97%; CCM 95%) and trauma (EM 96%; CCM 96%). Pre-EETI resuscitation using vasopressors was uncommon (4.9%). Training in CCM was associated with performing pre-EETI resuscitation (odds ratio, 2.20; 95% CI, [1.44–3.36], p<0.001).

Conclusion

Pre-EETI resuscitation is common among Canadian EM and CCM physicians. Most physicians use crystalloids pre-EETI as a resuscitation fluid, while few would give vasopressors. Physicians with CCM training were more likely to perform pre-EETI resuscitation.

Helicopter Evacuation Following a Rural Trauma: An Emergency Medicine Simulation Scenario Using Innovative Simulation Technology

The relevance of simulation as a teaching tool for medical professionals working in rural and remote contexts is apparent when low-frequency, high-risk situations are considered. Simulation training has been shown to enhance learning and improve patient outcomes in urban settings. However, there are few simulation scenarios designed to teach rural trauma management during complex medical transportation. In this technical report, we present a scenario using a medevac helicopter (Replica of Sikorsky S-92 designed by Virtual Marine Technology, St. John's, NL) at a rural community. This case can be used for training primary care physicians who are working in a rural or remote setting, or as an innovative addition to emergency medicine and pre-hospital care training programs.

The use of cricoid pressure during rapid sequence induction in trauma patients – UK and European practice compared

Introduction

There is ongoing debate and conflicting evidence surrounding the place of cricoid pressure (CP) as part of a rapid sequence induction (RSI) of anaesthesia. This study investigated the current use of CP during trauma RSI and compared reported practice in the UK with the rest of Europe.

Methods

An anonymised, web-based survey was sent to all clinicians registered as European Trauma Course instructors.

Results

CP use was reported by 83.1% of UK respondents and 39.4% from the rest of Europe, with an overall reported use of 49.8%. Anaesthetists use CP less commonly (35.6%) than clinicians from other specialties (63.6%). The most common reason given for not using CP (76.7%) was a perceived lack of evidence of effectiveness.

Conclusion

Generally the use of CP appears to be in decline with only half of all clinicians reporting to use it; however it remains much more commonly used in the UK than the rest of Europe.

Significant modification of traditional rapid sequence induction improves safety and effectiveness of pre-hospital trauma anaesthesia

INTRODUCTION

Rapid Sequence Induction of anaesthesia (RSI) is the recommended method to facilitate emergency tracheal intubation in trauma patients. In emergency situations, a simple and standardised RSI protocol may improve the safety and effectiveness of the procedure. A crucial component of developing a standardised protocol is the selection of induction agents. The aim of this study is to compare the safety and effectiveness of a traditional RSI protocol using etomidate and suxamethonium with a modified RSI protocol using fentanyl, ketamine and rocuronium.

METHODS

We performed a comparative cohort study of major trauma patients undergoing pre-hospital RSI by a physician-led Helicopter Emergency Medical Service. Group 1 underwent RSI using etomidate and suxamethonium and Group 2 underwent RSI using fentanyl, ketamine and rocuronium. Apart from the induction agents, the RSI protocol was identical in both groups. Outcomes measured included laryngoscopy view, intubation success, haemodynamic response to laryngoscopy and tracheal intubation, and mortality.

RESULTS

Compared to Group 1 (n = 116), Group 2 RSI (n = 145) produced significantly better laryngoscopy views (p = 0.013) and resulted in significantly higher first-pass intubation success (95% versus 100%; p = 0.007). A hypertensive response to laryngoscopy and tracheal intubation was less frequent following Group 2 RSI (79% versus 37%; p < 0.0001). A hypotensive response was uncommon in both groups (1% versus 6%; p = 0.05). Only one patient in each group developed true hypotension (SBP < 90 mmHg) on induction.

CONCLUSIONS

In a comparative, cohort study, pre-hospital RSI using fentanyl, ketamine and rocuronium produced superior intubating conditions and a more favourable haemodynamic response to laryngoscopy and tracheal intubation. An RSI protocol using fixed ratios of these agents delivers effective pre-hospital trauma anaesthesia.

The incidence of oxygen desaturation during rapid sequence induction and intubation

BACKGROUND

Rapid sequence induction and intubation (RSII) is an emergency airway management technique for patients with a risk of pulmonary aspiration. It involves preoxygenation, administration of predetermined doses of induction and paralytic drugs, avoidance of mask ventilation, and laryngoscopy followed by tracheal intubation and keeping cricoid pressure applied till endotracheal tube cuff be inflated. Oxygen desaturation has been seen during RSII. We assessed the incidence of oxygen desaturation during RSII.

METHODS

An institution-based observational study was conducted from March 3 to May 4, 2014 in our hospital. All patients who were operated upon under general anesthesia with RSII during the study period were included. A checklist was prepared for data collection.

RESULTS

A total of 153 patients were included in this study with a response rate of 91.6%. Appropriate drugs for RSII, equipments for RSII, equipments for difficult intubation, suction machine with a catheter, a monitor and an oxygen backup such as ambu bag were not prepared for 41 (26.8%), 50 (32.7%), 51 (33.3%), 38 (24.8%) and 25 (16.3%) patients respectively. Cricoid pressure was not applied at all for 17 (11.1%) patients and 53 (34.6%) patients were ventilated after induction of anesthesia but before intubation and endotracheal cuff inflation. A total of 55 (35.9%) patients desaturated during RSII (SPO2<95%). The minimum, maximum and mean oxygen desaturations were 26%, 94% and 70.9% respectively. The oxygen desaturation was in the range of <50%, 50%-64%, 65%-74%, 75%-84%, 85%-89 % and 90%-94% for 6 (3.9%), 7 (4.6%), 5 (3.3%), 10 (6.5%), 13 (8.5%) and 14 (9.2%) patients respectively.

CONCLUSION

The incidence of oxygen desaturation during RSII was high in our hospital. Preoperative patient optimization and training about the techniques of RSII should be emphasized.

Techniques of rapid sequence induction and intubation at a university teaching hospital

BACKGROUND

Rapid sequence induction and intubation (RSII) is a medical procedure involving a prompt induction of general anesthesia by using cricoid pressure that prevents regurgitation of gastric contents. The factors affecting RSII are prophylaxis for aspiration, preoxygenation, drug and equipment preparation for RSII, ventilation after induction till intubation and patient condition. We sometimes saw difficulties with the practice of this technique in our hospital operation theatres. The aim of this study was to assess the techniques of rapid sequence induction and intubation.

METHODS

Hospital based observational study was conducted with a standardized checklist. All patients who were operated upon under general anesthesia during the study period were included. The techniques of RSII were observed during the induction of anesthesia by trained anesthetists.

RESULTS

Altogether 140 patients were included in this study with a response rate of 95.2%. Prophylaxis was not given to 130 patients (92.2%), and appropriate drugs were not used for RSII in 73 patients (52.1%), equipments for difficult intubation in 21 (15%), suction machines with catheter not connected and turned on in 122 (87.1%), ventilation for patients after induction and before intubation in 41 (29.3%), cricoid pressure released before cuff inflation in 12 (12.1%), and difficult intubation in 8 (5.7%), respectively. RSII with cricoid pressure was applied appropriately in 94 (67.1%) patients, but cricoid pressure was not used in 46 (32.9%) patients.

CONCLUSIONS

The techniques of rapid sequence induction and intubation was low. Training should be given for anesthetists about the techniques of RSII.

Pre-hospital anaesthesia: the same but different

Advanced airway management is one of the most controversial areas of pre-hospital trauma care and is carried out by different providers using different techniques in different Emergency Medical Services systems. Pre-hospital anaesthesia is the standard of care for trauma patients arriving in the emergency department with airway compromise. A small proportion of severely injured patients who cannot be managed with basic airway management require pre-hospital anaesthesia to avoid death or hypoxic brain injury. The evidence base for advanced airway management is inconsistent, contradictory and rarely reports all key data. There is evidence that poorly performed advanced airway management is harmful and that less-experienced providers have higher intubation failure rates and complication rates. International guidelines carry many common messages about the system requirements for the practice of advanced airway management. Pre-hospital rapid sequence induction (RSI) should be practiced to the same standard as emergency department RSI. Many in-hospital standards such as monitoring, equipment, and provider competence can be achieved. Pre-hospital and emergency in-hospital RSI has been modified from standard RSI techniques to improve patient safety, physiological disturbance, and practicality. Examples include the use of opioids and long-acting neuromuscular blocking agents, ventilation before intubation, and the early release of cricoid pressure to improve laryngoscopic view. Pre-hospital RSI is indicated in a small proportion of trauma patients. Where pre-hospital anaesthesia cannot be carried out to a high standard by competent providers, excellent quality basic airway management should be the mainstay of management.

Optimal precurarizing dose of rocuronium to decrease fasciculation and myalgia following succinylcholine administration

Background

Succinylcholine commonly produces frequent adverse effects, including muscle fasciculation and myalgia. The current study identified the optimal dose of rocuronium to prevent succinylcholine-induced fasciculation and myalgia and evaluated the influence of rocuronium on the speed of onset produced by succinylcholine.

Methods

This randomized, double-blinded study was conducted in 100 patients randomly allocated into five groups of 20 patients each. Patients were randomized to receive 0.02, 0.03, 0.04, 0.05 and 0.06 mg/kg rocuronium as a precurarizing dose. Neuromuscular monitoring after each precurarizing dose was recorded from the adductor pollicis muscle using acceleromyography with train-of-four stimulation of the ulnar nerve. All patients received succinylcholine 1.5 mg/kg at 2 minutes after the precurarization, and were assessed the incidence and severity of fasciculations, while myalgia was assessed at 24 hours after surgery.

Results

The incidence and severity of visible muscle fasciculation was significantly less with increasing the amount of precurarizing dose of rocuronium (P < 0.001). Those of myalgia tend to decrease according to increasing the amount of precurarizing dose of rocuronium, but there was no significance (P = 0.072). The onset time of succinylcholine was significantly longer with increasing the amount of precurarizing dose of rocuronium (P < 0.001).

Conclusions

Precurarization with 0.04 mg/kg rocuronium was the optimal dose considering the reduction in the incidence and severity of fasciculation and myalgia with acceptable onset time, and the safe and effective precurarization.

Cricoid pressure: Where do we stand?

In 1961, Sellick popularized the technique of cricoid pressure (CP) to prevent regurgitation of gastric contents during anesthesia induction. In the last two decades, clinicians have begun to question the efficacy of CP and therefore the necessity of this maneuver. Some have suggested abandoning it on the grounds that this maneuver is unreliable in producing midline esophageal compression. Moreover, it has been found that application of CP makes tracheal intubation and mask ventilation difficult and induces relaxation of the lower esophageal sphincter. There have also been reports of regurgitation of gastric contents and aspiration despite CP. Further, its effectiveness has been demonstrated only in cadavers; therefore, its efficacy lacks scientific validation. These concerns with the use of CP in modern anesthesia practice have been briefly reviewed in this article.

Rapid-sequence intubation and cricoid pressure

Airway management is the most important clinical skill for anesthesiologist, emergency physician, and other providers who are involved in oxygenation and ventilation of the lungs. Rapid-sequence intubation is the preferred method to secure airway in patients who are at risk for aspiration because it results in rapid unconsciousness (induction) and neuromuscular blockade (paralysis). Application of cricoid pressure (CP) for patients undergoing rapid-sequence intubation is controversial. Multiple specialty societies have recommended that CP is not effective in preventing aspiration; rather it may worsen laryngoscopic view and impair bag-valve mask ventilation. Some experts think that CP should be applied in trauma and patients at risk for aspiration; however CP, if necessary, should be altered or removed to facilitate intubation.

Gastric tubes and airway management in patients at risk of aspiration: history, current concepts, and proposal of an algorithm

Rapid sequence induction and intubation (RSII) and awake tracheal intubation are commonly used anesthetic techniques in patients at risk of pulmonary aspiration of gastric or esophageal contents. Some of these patients may have a gastric tube (GT) placed preoperatively. Currently, there are no guidelines regarding which patient should have a GT placed before anesthetic induction. Furthermore, clinicians are not in agreement as to whether to keep a GT in situ, or to partially or completely withdraw it before anesthetic induction. In this review we provide a historical perspective of the use of GTs during anesthetic induction in patients at risk of pulmonary aspiration. Before the introduction of cricoid pressure (CP) in 1961, various techniques were used including RSII combined with a head-up tilt. Sellick initially recommended the withdrawal of the GT before anesthetic induction. He hypothesized that a GT increases the risk of regurgitation and interferes with the compression of the upper esophagus during CP. He later modified his view and emphasized the safety of CP in the presence of a GT. Despite subsequent studies supporting the effectiveness of CP in occluding the esophagus around a GT, Sellick's early view has been perpetuated by investigators who recommend partial or complete withdrawal of the GT. On the basis of available information, we have formulated an algorithm for airway management in patients at risk of aspiration of gastric or esophageal contents. The approach in an individual patient depends on: the procedure; type and severity of the underlying pathology; state of consciousness; likelihood of difficult airway; whether or not the GT is in place; contraindications to the use of RSII or CP. The algorithm calls for the preanesthetic use of a large-bore GT to remove undigested food particles and awake intubation in patients with achalasia, and emptying the pouch by external pressure and avoidance of a GT in patients with Zenker diverticulum. It also stipulates that in patients with gastric distension without predictable airway difficulties, a clinical and imaging assessment will determine the need for a GT and in severe cases an attempt to insert a GT should be made. In the latter cases, the success of placement will indicate whether to use RSII or awake intubation. The GT should not be withdrawn and should be connected to suction during induction. Airway management and the use of GTs in the surgical correction of certain gastrointestinal anomalies in infants and children are discussed.

The haemodynamic response to pre-hospital RSI in injured patients

BACKGROUND

Laryngoscopy and tracheal intubation provoke a marked sympathetic response, potentially harmful in patients with cerebral or cardiovascular pathology or haemorrhage. Standard pre-hospital rapid sequence induction of anaesthesia (RSI) does not incorporate agents that attenuate this response. It is not known if a clinically significant response occurs following pre-hospital RSI or what proportion of injured patients requiring the intervention are potentially at risk in this setting.

METHODS

We performed a retrospective analysis of 115 consecutive pre-hospital RSI's performed on trauma patients in a physician-led Helicopter Emergency Medical Service. Primary outcome was the acute haemodynamic response to the procedure. A clinically significant response was defined as a greater than 20% change from baseline recordings during laryngoscopy and intubation.

RESULTS

Laryngoscopy and intubation provoked a hypertensive response in 79% of cases. Almost one-in-ten patients experienced a greater than 100% increase in mean arterial pressure (MAP) and/or systolic blood pressure (SBP). The mean (95% CI) increase in SBP was 41(31-51) mmHg and MAP was 30(23-37) mmHg. Conditions leaving the patient vulnerable to secondary injury from a hypertensive response were common.

CONCLUSIONS

Laryngoscopy and tracheal intubation, following a standard pre-hospital RSI, commonly induced a clinically significant hypertensive response in the trauma patients studied. We believe that, although this technique is effective in securing the pre-hospital trauma airway, it is poor at attenuating adverse physiological effects that may be detrimental in this patient group.

[Changes in kaliemia following rapid sequence induction with succinylcholine in critically ill patients]

OBJECTIVE

Evaluate the changes in potassium following rapid sequence induction with succinylcholine in critically ill-patients and determine whether hospital length of stay could influence the succinylcholine-induced hyperkaliemia.

STUDY DESIGN

Prospective and observational study.

PATIENTS AND METHODS

After approval by our local ethical committee, we prospectively included 36 patients admitted from more than 24hours in ICU and who required succinylcholine for rapid tracheal intubation (1mg/kg). Serum potassium was measured before, 5 and 30min after succinylcholine. The incidence of life-threatening hyperkaliemia (≥6.5mmol/L) was noted.

RESULTS

We could observe significant and transient increase in serum potassium (median increase of 0.45 [0.20-0.80] mmol/L at five minutes). A significant relationship was observed between the ICU length of stay and arterial potassium increase (r=0.37, P<0.05). From the ROC curve, a threshold of 12 days had an 86% sensitivity and 69% specificity in discriminating patients in whom the potassium increase was more than 1.5mmol/L.

CONCLUSION

Induction with succinylcholine is followed by significant but transient hyperkaliema. The ICU length of stay before giving succinylcholine could influence significantly the amplitude of potassium increase.

Effectiveness of cricoid pressure in preventing gastric aspiration during rapid sequence intubation in the emergency department: study protocol for a randomised controlled trial

Background

Cricoid pressure is considered to be the gold standard means of preventing aspiration of gastric content during Rapid Sequence Intubation (RSI). Its effectiveness has only been demonstrated in cadaveric studies and case reports. No randomised controlled trials comparing the incidence of gastric aspiration following emergent RSI, with or without cricoid pressure, have been performed. If improperly applied, cricoid pressure increases risk to the patient. The clinical significance of aspiration in the emergency department is unknown. This randomised controlled trial aims to; 1. Compare the application of the 'ideal" amount of force (30 - 40 newtons) to standard, unmeasured cricoid pressure and 2. Determine the incidence of clinically defined aspiration syndromes following RSI using a fibrinogen degradation assay previously described.

Methods/design

212 patients requiring emergency intubation will be randomly allocated to either control (unmeasured cricoid pressure) or intervention groups (30 - 40 newtons cricoid pressure). The primary outcome is the rate of aspiration of gastric contents (determined by pepsin detection in the oropharyngeal/tracheal aspirates or treatment for aspiration pneumonitis up to 28 days post-intubation). Secondary outcomes are; correlation between aspiration and lowest pre-intubation Glasgow Coma Score, the relationship between detection of pepsin in trachea and development of aspiration syndromes, complications associated with intubation and grade of the view on direct largyngoscopy.

Discussion

The benefits and risks of cricoid pressure application will be scrutinised by comparison of the incidence of aspiration and difficult or failed intubations in each group. The role of cricoid pressure in RSI in the emergency department and the use of a pepsin detection as a predictor of clinical aspiration will be evaluated.

Trial registration

Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12611000587909

Modified rapid sequence induction and intubation: a survey of United States current practice

BACKGROUND

Rapid sequence induction and intubation (RSII) is a technique commonly used to resist regurgitation of gastric contents and protect the airway. A modification of this technique is implemented in certain clinical circumstances. However, there is currently no standard definition for a modified RSII. Therefore, we surveyed clinicians at academic centers across the United States to establish a working definition of a modified RSII as well as the clinical scenarios in which it is being used.

METHODS

A survey was created that queried the use and definition of modified RSII, and validated with test respondents. We then mailed the survey to all 131 anesthesia residency training programs across the United States. Logistic regression models were created to estimate the percentage of affirmative responses among respondents that performed modified RSII procedures and answered survey items in a consistent manner. Similar quantities were calculated by physician status (resident and attending).

RESULTS

Four hundred ninety surveys were received from 58 institutions (44% institution response rate); 93% of respondents reported using a modified RSII, and of those 85% consistently completed the survey instrument. A majority of respondents (71%, CI: 63%-77%) reported administering oxygen before anesthesia induction, applying cricoid pressure, and attempting to ventilate the lungs via a facemask before securing the airway. Respondents noted that they would use a modified RSII procedure if the patient were either moderately or morbidly obese (each ∼59%, 53%-64%), had a history but no current symptoms of gastroesophageal reflux disease (52%, 46%-57%), had a hiatal hernia (42%, 36%-48%) or were a trauma patient who had been NPO for at least 8 h (39%, 33%-45%). Similar RSII results were obtained when repeating the analysis on the subset that did not enforce the consistency requirements.

CONCLUSIONS

Based on our survey we have established three defining features of a modified RSII: (1) oxygen administration before induction; (2) the use of cricoid pressure; and (3) an attempt to ventilate the patient's lungs before securing the airway. Although this definition seems intuitively obvious, no previous work has tested whether it is commonly accepted.

Remifentanil attenuates muscle fasciculations by succinylcholine

PURPOSE

The present visual and electromyographic study was designed to evaluate muscle fasciculations caused by succinylcholine in adults pretreated with either remifentanil 1.5 microg/kg or saline.

MATERIALS AND METHODS

The effect of remifentanil on succinylcholine-induced muscle fasciculations was studied using a double-blind method in 40 adults. After i.v. pretreatment with either remifentanil 1.5 microg/kg (remifentanil group, n = 20) or an equivalent volume of i.v. saline (saline group, n = 20), patients were anaesthetized with a 2.0 mg/kg of i.v. propofol followed by i.v. succinylcholine 1.0 mg/kg. Intensity and duration of muscle fasciculation following i.v. succinylcholine administration were recorded. Electromyography (EMG) was used to quantify the extent of muscle fasciculation following i.v. succinylcholine injection. Myalgia was evaluated 24 hours after induction time. Serum potassium levels were measured five minutes after i.v. succinylcholine administration and creatine kinase (CK) levels 24 hours after induction time.

RESULTS

Compared to saline treated controls, remifentanil decreased the intensity of muscle fasciculations caused by i.v. succinylcholine [fasciculation severity scores (grade 0 to 3) were 2/1/12/5 and 3/13/4/0 (patients numbers) in the saline group and the remifentanil group, respectively, p < 0.001]. The mean (SD) maximum amplitude of muscle action potential (MAP) by EMG was smaller in the remifentanil group [283.0 (74.4) microV] than in the saline group [1480.4 (161.3) microV] (p = 0.003). Postoperative serum CK levels were lower in the remifentanil group (p < 0.001). Postoperative myalgia was not different between the two groups.

CONCLUSION

Remifentanil 1.5 microg/kg attenuated intensity of muscle fasciculations by succinylcholine.

Teaching anaesthetic nurses optimal force for effective cricoid pressure: a literature review

AIMS AND OBJECTIVES

This literature review explores the role of force and education in cricoid pressure, an essential aspect of practice for any nurse within a critical care environment.

BACKGROUND

Cricoid pressure is utilized in everyday practice during rapid sequence induction (RSI) of anaesthesia. The purpose of cricoid pressure is to occlude the oesophagus in order to reduce the risk of acid aspiration during emergency induction of anaesthesia. The importance of best practice cannot be overstated because of high rates of mortality following acid aspiration.

METHODS

Literature searches were conducted using the key words cricoid pressure, Sellick manoeuvre, rapid sequence induction and acid aspiration syndrome. Articles were obtained from online searches, with literature published in the last 10 years being used; some seminal literature and textbooks were incorporated for definition purposes.

RESULTS

The literature displayed a disparity in practice and differing opinions on the optimal force to occlude the oesophagus. The role of education in correct application of cricoid pressure was explored, with unanimous conclusions that education plays a role in ensuring best practice.

CONCLUSIONS

Forces of 20-30 N are adequate to occlude the oesophagus and minimize the risk of acid aspiration. However, it is difficult for practitioners to accurately estimate this force in everyday practice. Various methods of assessing force were discussed, with the use of a 50-mL syringe suggested as a cost-effective and simple method to utilize in practice.

RELEVANCE TO CLINICAL PRACTICE

The literature review demonstrated that the subject of cricoid pressure is relevant in critical care practice in order to ensure patient safety during RSI. Thus, all critical care nurses have a duty to gain a working knowledge on the subject if patient safety is to be maintained. This paper provides a source of information on cricoid pressure and realistic methods of maintaining best practice.