The effects of systemic lidocaine on airway tone and pulmonary function in asthmatic subjects

Perioperative Care of the Pediatric Patient and an Algorithm for the Treatment of Intraoperative Bronchospasm

Asthma remains a common comorbid condition in patients presenting for anesthetic care. As a chronic inflammatory disease of the airway, asthma is known to increase the risk of intraoperative bronchospasm. As the incidence and severity of asthma and other chronic respiratory conditions that alter airway reactivity is increasing, a greater number of patients at risk for perioperative bronchospasm are presenting for anesthetic care. As bronchospasm remains one of the more common intraoperative adverse events, recognizing and mitigating preoperative risk factors and having a pre-determined treatment algorithm for acute events are essential to ensuring effective resolution of this intraoperative emergency. The following article reviews the perioperative care of pediatric patients with asthma, discusses modifiable risk factors for intraoperative bronchospasm, and outlines the differential diagnosis of intraoperative wheezing. Additionally, a treatment algorithm for intraoperative bronchospasm is suggested.

Pharmacotherapy optimization for rapid sequence intubation in the emergency department

PURPOSE

Rapid-sequence intubation (RSI) is the process of administering a sedative and neuromuscular blocking agent (NMBA) in rapid succession to facilitate endotracheal intubation. It is the most common and preferred method for intubation of patients presenting to the emergency department (ED). The selection and use of medications to facilitate RSI is critical for success. The purpose of this review is to describe pharmacotherapies used during the RSI process, discuss current clinical controversies in RSI medication selection, and review pharmacotherapy considerations for alternative intubation methods.

SUMMARY

There are several steps to the intubation process requiring medication considerations, including pretreatment, induction, paralysis, and post-intubation sedation and analgesia. Pretreatment medications include atropine, lidocaine, and fentanyl; but use of these agents in clinical practice has fallen out of favor as there is limited evidence for their use outside of select clinical scenarios. There are several options for induction agents, though etomidate and ketamine are the most used due to their more favorable hemodynamic profiles. Currently there is retrospective evidence that etomidate may produce less hypotension than ketamine in patients presenting with shock or sepsis. Succinylcholine and rocuronium are the preferred neuromuscular blocking agents, and the literature suggests minimal differences between succinylcholine and high dose rocuronium in first-pass success rates. Selection between the two is based on patient specific factors, half-life and adverse effect profiles. Finally, medication-assisted preoxygenation and awake intubation are less common methods for intubation in the ED but require different considerations for medication use.

AREAS FOR FUTURE RESEARCH

The optimal selection, dosing, and administration of RSI medications is complicated, and further research is needed in several areas. Additional prospective studies are needed to determine optimal induction agent selection and dosing in patients presenting with shock or sepsis. Controversy exists over optimal medication administration order (paralytic first vs induction first) and medication dosing in obese patients, but there is insufficient evidence to significantly alter current practices regarding medication dosing and administration. Further research examining awareness with paralysis during RSI is needed before definitive and widespread practice changes to medication use during RSI can be made.

Anesthetic considerations in children with asthma

Due to the high prevalence of asthma and general airway reactivity, anesthesiologists frequently encounter children with asthma or asthma-like symptoms. This review focuses on the epidemiology, the underlying pathophysiology, and perioperative management of children with airway reactivity, including controlled and uncontrolled asthma. It spans from preoperative optimization to optimized intraoperative management, airway management, and ventilation strategies. There are three leading causes for bronchospasm (1) mechanical (eg, airway manipulation), (2) non-immunological anaphylaxis (anaphylactoid reaction), and (3) immunological anaphylaxis. Children with increased airway reactivity may benefit from a premedication with beta-2 agonists, non-invasive airway management, and deep removal of airway devices. While desflurane should be avoided in pediatric anesthesia due to an increased risk of bronchospasm, other volatile agents are potent bronchodilators. Propofol is superior in blunting airway reflexes and, therefore, well suited for anesthesia induction in children with increased airway reactivity.

Is Corticosteroid of No Use for Pediatric Patients with Common Cold Undergoing Anesthesia? A Randomized, Double-Blind, Clinical Trial

Background

Use of laryngeal mask airways (LMAs) has been advocated for children with upper respiratory tract infection (URI). However, no randomized trial has yet compared intravenous corticosteroids versus placebo in these patients.

Objectives

We hypothesized the lower incidence of postoperative cough (as the primary outcome) with intravenous corticosteroid versus placebo in pediatric patients with mild URI, who were anesthetized with LMA.

Methods

A total of 210 patients with mild URI, aged 1 - 6 years, were included. The patients underwent full ophthalmic examination immediately (within few days). They were randomized to receive either intravenous corticosteroids (1 mg/kg of hydrocortisone and 0.1 mg/kg of dexamethasone 10 minutes prior to anesthesia induction) or placebo. Anesthesia was induced with sevoflurane. Following LMA insertion, the patients were maintained on anesthesia with spontaneous ventilation on N₂O, O₂, and 3% sevoflurane; LMA was removed under deep anesthesia. The outcomes were evaluated during anesthesia, recovery, and the first postoperative week.

Results

A total of 204 patients completed the trial. Cough, which was designated as the primary outcome, was not significantly different among patients receiving corticosteroids and placebo (31% vs. 34%; P = 0.7). Also, the incidence of laryngospasm (16% vs. 14%), apnea (9% VS 5%), desaturation (4% vs. 5%), bronchospasm (14% vs. 7%), vomiting (4% vs. 6%), and postoperative symptoms (8% vs. 7%) was not significantly different between the groups.

Conclusions

Based on the present research, intravenous injection of corticosteroids has no beneficial effects for pediatric patients with minor uncomplicated URI (without a history of allergy), undergoing LMA anesthesia.

Lignocaine topicalization of the pediatric airway

The application of topical laryngeal lignocaine is a technique used frequently in pediatric anesthesia. It is often used to facilitate open airway procedures, tracheal intubation, or to reduce the incidence of perioperative adverse respiratory events such as coughing and laryngospasm. A number of studies have shown that applying topical lignocaine to the larynx reduces perioperative respiratory adverse events, while others have shown an increased incidence of respiratory complications with lignocaine administration. There is a lack of evidence on the effect of topical lignocaine on the sensitivity of upper airway reflexes and swallowing, the duration of time that airway reflexes are obtunded, and the optimum and safe maximum dose of lignocaine when used by this route. We review the current literature relating to the use of lignocaine to topicalize the pediatric airway. This review concentrates on the indications for use, the maximum safe dose, the effect on swallowing, and risk of aspiration and the complications of the technique.

Anaesthesia for children with bronchial asthma and respiratory infections

Asthma represents one of the most common chronic diseases in children with an increasing incidence reported worldwide. The key to successful anaesthetic outcome involves thorough pre-operative assessment and optimisation of the child's pulmonary status. Judicious application of proper anti-inflammatory and bronchodilatory regimes should be instituted as part of pre-operative preparation. Bronchospasm triggering agents should be carefully probed and meticulously avoided. A calm and properly sedated child at the time of induction is ideal, so also is extubation in a deep plane with an unobstructed airway. Wherever possible, regional anaesthesia should be employed. This will avoid airway manipulations, with additional benefit of excellent peri-operative analgesia. Agents with a potential for histamine release and techniques that can increase airway resistance should be diligently avoided. Emphasis must be given to proper post-operative care including respiratory monitoring, analgesia and breathing exercises.

Anesthesia and ventilation strategies in children with asthma: part II - intraoperative management

PURPOSE OF REVIEW

As asthma is a frequent disease especially in children, anesthetists are increasingly providing anesthesia for children requiring elective surgery with well controlled asthma but also for those requiring urgent surgery with poorly controlled or undiagnosed asthma. This second part of this two-part review details the medical and ventilatory management throughout the perioperative period in general but also includes the perioperative management of acute bronchospasm and asthma exacerbations in children with asthma.

RECENT FINDINGS

Multiple observational trials assessing perioperative respiratory adverse events in healthy and asthmatic children provide the basis for identifying risk reduction strategies. Mainly, animal experiments and to a small extent clinical data have advanced our understanding of how anesthetic agents effect bronchial smooth muscle tone and blunt reflex bronchoconstriction. Asthma treatment outside anesthesia is well founded on a large body of evidence.Perioperative prevention strategies have increasingly been studied. However, evidence on the perioperative management, including mechanical ventilation strategies of asthmatic children, is still only fair, and further research is required.

SUMMARY

To minimize the considerable risk of perioperative respiratory adverse events in asthmatic children, perioperative management should be based on two main pillars: the preoperative optimization of asthma treatment (please refer to the first part of this two-part review) and - the focus of this second part of this review - the optimization of anesthesia management in order to optimize lung function and minimize bronchial hyperreactivity in the perioperative period.

Anaesthetic management of the child with co-existing pulmonary disease

Children with co-existing pulmonary disease have a wide range of clinical manifestations with significant implications for anaesthetists. Although there are a number of pulmonary diseases in children, this review focuses on two of the most common pulmonary disorders, asthma and bronchopulmonary dysplasia (BPD). These diseases share the physiology of bronchoconstriction and variably decreased flow in the airways, but also have unique physiological consequences. The anaesthetist can make a difference in outcomes with proper preoperative evaluation and appropriate preparation for surgery in the context of a team approach to perioperative care with implementation of a stepwise approach to disease management. An understanding of the importance of minimizing the risk for bronchoconstriction and having the tools at hand to treat it when necessary is paramount in the care of these patients. Unique challenges exist in the management of pulmonary hypertension in BPD patients. This review covers medical treatment, intraoperative management, and postoperative care for both patient populations.

Update on perioperative management of the child with asthma

Asthma represents the leading cause of morbidity from a chronic disease among children. Dealing with this disease during the perioperative period of pediatric surgical procedures is, therefore, quite common for the anesthesiologist and other professionalities involved. Preoperative assessment has a key role in detecting children at increased risk of perioperative respiratory complications. For children without an optimal control of symptoms or with a recent respiratory tract infection elective surgery should be postponed, if possible, after the optimization of therapy. According to clinical setting, loco-regional anesthesia represents the desirable option since it allows to avoid airway instrumentation. Airway management goals are preventing the increase of airflow resistance during general anesthesia along with avoiding triggers of bronchospasm. When their use is possible, face mask ventilation and laringeal mask are considered more reliable than tracheal intubation for children with asthma. Sevoflurane is the most commonly used anesthetic for induction and manteinance. Salbutamol seems to be useful in preventing airflow resistance rise after endotracheal intubation. Mechanical ventilation should be tailored according to pathophysiology of asthma: an adequate expiratory time should be setted in order to avoid a positive end-expiratory pressure due to expiratory airflow obstruction. Pain should be prevented and promptly controlled with a loco-regional anesthesia technique when it is possible. Potential allergic reactions to drugs or latex should always be considered during the whole perioperative period. Creating a serene atmosphere should be adopted as an important component of interventions in order to guarantee the best care to the asthmatic child.

Risk assessment for respiratory complications in paediatric anaesthesia: a prospective cohort study

BACKGROUND

Perioperative respiratory adverse events in children are one of the major causes of morbidity and mortality during paediatric anaesthesia. We aimed to identify associations between family history, anaesthesia management, and occurrence of perioperative respiratory adverse events.

METHODS

We prospectively included all children who had general anaesthesia for surgical or medical interventions, elective or urgent procedures at Princess Margaret Hospital for Children, Perth, Australia, from Feb 1, 2007, to Jan 31, 2008. On the day of surgery, anaesthetists in charge of paediatric patients completed an adapted version of the International Study Group for Asthma and Allergies in Childhood questionnaire. We collected data on family medical history of asthma, atopy, allergy, upper respiratory tract infection, and passive smoking. Anaesthesia management and all perioperative respiratory adverse events were recorded.

FINDINGS

9297 questionnaires were available for analysis. A positive respiratory history (nocturnal dry cough, wheezing during exercise, wheezing more than three times in the past 12 months, or a history of present or past eczema) was associated with an increased risk for bronchospasm (relative risk [RR] 8.46, 95% CI 6.18-11.59; p<0.0001), laryngospasm (4.13, 3.37-5.08; p<0.0001), and perioperative cough, desaturation, or airway obstruction (3.05, 2.76-3.37; p<0.0001). Upper respiratory tract infection was associated with an increased risk for perioperative respiratory adverse events only when symptoms were present (RR 2.05, 95% CI 1.82-2.31; p<0.0001) or less than 2 weeks before the procedure (2.34, 2.07-2.66; p<0.0001), whereas symptoms of upper respiratory tract infection 2-4 weeks before the procedure significantly lowered the incidence of perioperative respiratory adverse events (0.66, 0.53-0.81; p<0.0001). A history of at least two family members having asthma, atopy, or smoking increased the risk for perioperative respiratory adverse events (all p<0.0001). Risk was lower with intravenous induction compared with inhalational induction (all p<0.0001), inhalational compared with intravenous maintenance of anaesthesia (all p<0.0001), airway management by a specialist paediatric anaesthetist compared with a registrar (all p<0.0001), and use of face mask compared with tracheal intubation (all p<0.0001).

INTERPRETATION

Children at high risk for perioperative respiratory adverse events could be systematically identified at the preanaesthetic assessment and thus can benefit from a specifically targeted anaesthesia management.

FUNDING

Department of Anaesthesia, Princess Margaret Hospital for Children, Swiss Foundation for Grants in Biology and Medicine, and the Voluntary Academic Society Basel.

Bronchospasm after intravenous lidocaine

IV lidocaine (1.5 mg/kg) administered to facilitate endotracheal intubation was associated with transient bronchospasm in a 17-month-old-female with mild intermittent asthma. Immediately after lidocaine administration, the patient developed diffuse bilateral expiratory wheezes and dramatic increases in peak inspiratory pressure. Over approximately 5 min the episode resolved and an uneventful anesthetic course followed. This is consistent with recent clinical studies suggesting that IV lidocaine may cause airway narrowing in asthmatics. Practitioners should be aware of this potential complication.