The effects of common airway maneuvers on airway pressure and flow in children undergoing adenoidectomies

Developmental respiratory physiology

Various developmental aspects of respiratory physiology put infants and young children at an increased risk of respiratory failure, which is associated with a higher rate of critical incidents during anesthesia. The immaturity of control of breathing in infants is reflected by prolonged central apneas and periodic breathing, and an increased risk of apneas after anesthesia. The physiology of the pediatric upper and lower airways is characterized by a higher flow resistance and airway collapsibility. The increased chest wall compliance and reduced gas exchange surface of the lungs reduce the pulmonary oxygen reserve vis-à-vis a higher metabolic oxygen demand, which causes more rapid oxygen desaturation when ventilation is compromised. This review describes the various developmental aspects of respiratory physiology and summarizes anesthetic implications.

Comparative evaluation of one-handed versus two-handed mask holding techniques in children during inhalational induction of anesthesia: A randomized crossover study

BACKGROUND

We aimed to evaluate if two-handed mask airway is superior to one-handed mask airway during inhalational induction of anesthesia in children.

METHODS

A randomized, two period, crossover study was performed on 60 children aged 1-8 years, with obstructive sleep apnea due to adenotonsillar hypertrophy, scheduled for adenotonsillectomy. Children were assigned to two study sequences and one control sequence of 20 subjects each. A control sequence was added to evaluate the effect of anesthetic depth. Sequence 1: One-handed followed by two-handed airway, 30 seconds each; Sequence 2: two-handed followed by one-handed airway, 30 seconds each and Sequence 3: two-handed airway, for 60 seconds. The work of breathing indices, phase angle, and labored breathing index were recorded using respiratory inductance plethysmography. Additional outcome measures were tidal volume, minute ventilation, and respiratory rate. A straight comparison and a crossover analysis was performed.

RESULTS

The initial comparison revealed that one-handed airway had greater phase angle (mean diff. 17.4; 95% confidence interval [CI] 1.07-33.68; P = .034), greater labored breathing index (mean diff. 0.56; 95% CI 0.16-1.04; P = .004),lower minute ventilation (mean diff. -1567; 95% CI -2695 to -5.4; P = .004),and lower tidal volume (mean diff. -39; 95% CI -2.7 to -5.4; P = .02) than two-handed airway. On crossover analysis, within-subject difference in the phase angle was greater during one-handed than two-handed airway (34.3; 95% CI 8.46-60.14; P = .01) as was labored breathing index (mean diff. 1.2; 95% CI 0.39-2.00; P < .0046).Minute ventilation was lower during one-handed than two-handed airway (mean diff. -3359; 95% CI -4363 to -2355, P < 0.0001) as was tidal volume(mean diff. -78; 95% CI -110.4 to -45.8; P < .0001).

CONCLUSION

In children with obstructive sleep apnea due to adenotonsillar hypertrophy, two-handed airway provides superior airway patency that was not influenced by the anesthetic depth.

Laryngeal reflex responses in pediatric anesthesia

Laryngeal and respiratory reflexes are vitally important defense mechanisms against foreign body aspiration, safeguarding airway patency, and ventilation. These highly preserved automatisms easily overrule external influences like willpower or (anesthetic) medication. Prevention and anticipation are, therefore, the essential strategies to avoid adverse events and damage, and treatment is most effective in the early stage of the reflex response. The physiology and pathophysiology of the various defensive reflexes as well as a comprehensive anesthetic approach to prevention and treatment are outlined in this review.

Serious airway-related adverse events with sevoflurane anesthesia via facemask for magnetic resonance imaging in 7129 pediatric patients: A retrospective study

OBJECTIVE

This retrospective study evaluated the safety and effectiveness of sevoflurane anesthesia by facemask for magnetic resonance imaging (MRI) scanning among pediatric patients in a high-volume MRI department.

METHODS

The medical records of 7129 pediatric patients (median age 12 months, range 4.0-36.0 months) who were administered anesthesia during MRI scanning were reviewed. Anesthesia via 8% and 1.5%-2% sevoflurane was used for induction and maintenance, respectively. All the patients were monitored by anesthetists in the postanesthesia care unit. Vital signs were recorded every 5 minutes. Airway-related adverse events, sevoflurane induction time, MRI scanning time, and recovery time were recorded. Patients were discharged when no complications were found for 10-15 minutes, with Aldrete's score ≥9.

RESULTS

After sevoflurane anesthesia, there were 28 severe airway-related adverse events (0.4%, 95% CI: 0.2%-0.5%), and 12 patients had severe respiratory apnea (0.2%, 95% CI: 0.1%-0.2%). The percentage of patients with respiratory apnea was significantly higher in preterm infants compared with term infants (2.4% cf. 0.5%, P = 0.012). Sixteen patients had severe airway obstruction (0.2%, 95% CI: 0.1%-0.3%).

CONCLUSION

The major severe airway-related adverse events among pediatric patients associated with sevoflurane anesthesia were respiratory apnea and airway obstruction. The respiratory condition of preterm infants should be monitored carefully when under sevoflurane anesthesia. Overall, sevoflurane is safe and can be used efficiently for pediatric anesthesia in high-volume MRI departments.

[The influence of airway supporting maneuvers on glottis view in pediatric fiberoptic bronchoscopy]

INTRODUCTION

Flexible fiber optic bronchoscopy is a valuable intervention for evaluation and management of respiratory diseases in both infants, pediatric and adult patients. The aim of this study is to investigate the influence of the airway supporting maneuvers on glottis view during pediatric flexible fiberoptic bronchoscopy.

MATERIALS AND METHODS

In this randomized, controlled, crossover study; patients aged between 0 and 15 years who underwent flexible fiberoptic bronchoscopy procedure having American Society of Anesthesiologists I-II risk score were included. Patients having risk of difficult intubation, intubated or patients with tracheostomy, and patients with reduced neck mobility or having cautions for neck mobility were excluded from this study. After obtaining best glottic view at the neutral position, patients were positioned jaw trust with open mouth, jaw trust with teeth prottution, head tilt chin lift and triple airway maneuvers and best glottis scores were recorded.

RESULTS

Total of 121 pediatric patients, 57 girls and 64 boys, were included in this study. Both jaw trust with open mouth and jaw trust with teeth prottution maneuvers improved the glottis view compared with neutral position (p<0.05), but we did not observe any difference between jaw trust with open mouth and jaw trust with teeth prottution maneuvers (p>0.05). Head tilt chin lift and triple airway maneuvers improved glottis view when compared with both jaw trust with open mouth and jaw trust with teeth prottution maneuvers and neutral position (p<0.05); however we found no differences between head tilt chin lift and triple airway maneuvers (p>0.05).

CONCLUSION

All airway supporting maneuvers improved glottic view during pediatric flexible fiberoptic bronchoscopy; however head tilt chin lift and triple airway maneuvers were found to be the most effective maneuvers.

Motion generated in the unstable upper cervical spine during head tilt-chin lift and jaw thrust maneuvers

BACKGROUND CONTEXT

Although it is essential to maintain a secure airway in a trauma patient, it is also critical to protect the potentially injured cervical spine. It has previously been suggested that the jaw thrust maneuver be used in place of the head tilt-chin lift in the suspected spine-injured patient.

PURPOSE

We sought to examine whether the jaw thrust was in fact safer to use in the setting of an unstable upper cervical spine injury.

METHODS

Unstable, dissociative C1-C2 injuries were surgically created in nine fresh, lightly embalmed human cadaver specimens. An electromagnetic motion analysis device was used to assess the amount of angular and linear motion with sensors placed above and below the injured segment. Measurements were recorded during execution of the two airway maneuvers. Trials were performed both with and without a cervical immobilization collar in place.

RESULTS

There was almost twice as much angular motion in all planes when performing a head tilt-chin lift as compared with the jaw thrust, and this was statistically significant (p<.013). In addition, there was more displacement at the injured level with a head tilt-chin lift as compared with the jaw thrust. This was statistically significant for axial displacement and anteroposterior translation (p=.003 for both), and approached significance for mediolateral translation (p=.056).

CONCLUSIONS

The jaw thrust maneuver results in less motion at an unstable C1-C2 injury as compared with the head tilt-chin lift maneuver. We therefore recommend the use of the jaw thrust to improve airway patency in the trauma patient with suspected cervical spine injury.

Nasal versus oronasal raised volume forced expirations in infants--a real physiologic challenge

Raised volume rapid thoracoabdominal compression (RTC) generates forced expiration (FE) in infants typically from an airway opening pressure of 30 cm H(2)O (V(30)). We hypothesized that the higher nasal than pulmonary airway resistance limits forced expiratory flows (FEF(%)) during (nasal) FE(n), which an opened mouth, (oronasal) FE(o), would resolve. Measurements were performed during a brief post-hyperventilation apnea on 12 healthy infants aged 6.9-104 weeks. In two infants, forced expiratory (FEFV) flow volume (FV) curves were generated using a facemask that covered the nose and a closed mouth, then again with a larger mask with the mouth opened. In other infants (n = 10), the mouth closed spontaneously during FE. Oronasal passive expiration from V(30) generated either the inspiratory capacity (IC) or by activating RTC before end-expiration, the slow vital capacity ((j) SVC). Peak flow (PF), FEF(25), FEF(50), FEF(25-75), FEV(0.4), and FEV(0.5) were lower via FE(n) than FE(o) (P < 0.05), but the ratio of expired volume at PF and forced vital capacity (FVC) as percent was higher (P < 0.05). FEF(75), FEF(85), FEF(90), FVC as well as the applied jacket pressures were not different (P > 0.05). FEFV curves generated via FE(o) exhibited higher PF than FV curves of IC (P < 0.05); PF of those produced via FE(n) were not different from FV curves of IC (P > 0.05) but lower than those of (j) SVC (P < 0.05). In conclusion, the higher nasal than pulmonary airways resistance unequivocally affects the FEFV curves by consistently reducing PF and decreases mid-expiratory flows. A monitored slightly opened mouth and a gentle anterior jaw thrust are physiologically integral for raised volume RTC in order to maximize the oral and minimize nasal airways contribution to FE so that flow limitation would be in the pulmonary not nasal airways.

A Novel Design for a Jaw-Thrust and Head Immobilization Device and its Successful Testing Using a Human Simulator

Jaw thrust is a common maneuver performed by medical care providers to open and maintain an airway in an unconscious patient. This essential procedure not only occupies a significant amount of time for the health care provider, but can also result in physical discomfort (low back pain) or fatigue when it is performed for an extended period of time. A mechanical device would not only prevent fatigue of the provider, but it can also free up time to perform other necessary tasks in management of the critically ill patient. The aim of this study is to develop a novel mechanical device that can perform jaw thrust on older children and adults along with maintaining an open airway. The jaw thrust device includes an extension arm mounted on a base to be placed on each side of the patient’s head. The mandible rest (jaw thruster) is mounted on each extension arm such that it can be positioned under the patient’s jaw. A chinstrap with rubber tubing is placed on four points across the base. A jaw thrusting pressure on the mandible rest causes a rotational force on the chin straps. This opens the mouth without substantially tilting the patient’s head. The device then maintains an open airway without any continuous attention. The supports on each side also immobilize the head in the midline and helps in maintaining the alignment of the cervical vertebrae. Finite element analyses of each of the components were done and a prototype was built for functional evaluation on a patient simulator. The device, when tested and applied to a human patient simulator in an ‘obstructed airway state,’ was able to open the airway evidenced by a cough reflex elicited in response. An ‘airway opened’ timestamp was also noted in the computer attached to the simulator.

Airway management

The pediatric airway and respiratory function differ from those in adults. Optimum management requires consideration of these differences, but the application of adult principles is usually sufficient to buy time in an emergency until specialist pediatric help is available. Simple airway opening techniques such as head tilt and jaw thrust are usually sufficient to open the child's airway, but there is now a range of equipment available to bypass supraglottic airway obstruction-the strengths and weaknesses of such devices are explored in this article. The role of endotracheal intubation is also discussed, along with the pros and cons of the use of cuffed endotracheal tubes in children, and methods of confirming tracheal placement of the tube.

The effects of jaw thrust and the lateral position on heart rate variability in anesthetized children with obstructive sleep apnea syndrome

BACKGROUND

Airway obstruction occurs in anesthetized children with obstructive sleep apnea syndrome (OSAS). The inspiratory attempts against the occluded airway lead to an increased sympathetic activity. Heart rate variability (HRV) analysis provides information about the autonomic nervous system. The low-frequency component/high-frequency component ratio of HRV is considered to be an index of sympatho-parasympathetic balance.

METHODS

We investigated the effects of general anesthesia, the neutral neck position, and jaw thrust in the supine and lateral positions on HRV in 20 children (aged 3-9 yr), with OSAS. HRV was recorded before and after anesthesia induction, at the neutral neck position and with jaw thrust maneuver in the supine and lateral positions with the patients breathing 5% sevoflurane.

RESULTS

General anesthesia with the patient in the neutral neck position increased airway obstruction. The patients' stridor scores improved with the airway maneuver of jaw thrust and lateral position. The low-frequency component/high-frequency component ratio and heart rate increased at the postinduction measurement and reached the highest value with the patient in the neutral neck position. The values significantly decreased with the jaw thrust maneuver and with the patient in the supine and lateral positions. Ultra-short-term entropy of HRV decreased after anesthetic induction and reached the lowest value with the patient in the neutral neck position. The values increased during jaw thrust and with patients in the supine and lateral positions.

CONCLUSIONS

Changes of HRV induced by inhaled anesthesia, jaw thrust, and lateral positioning procedures corresponded to changes in the stridor score of children with OSAS.

2005 American Heart Association (AHA) guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care (ECC) of pediatric and neonatal patients: pediatric basic life support

This publication presents the 2005 American Heart Association (AHA) guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care (ECC) of the pediatric patient and the 2005 American Academy of Pediatrics/AHA guidelines for CPR and ECC of the neonate. The guidelines are based on the evidence evaluation from the 2005 International Consensus Conference on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations, hosted by the American Heart Association in Dallas, Texas, January 23-30, 2005. The "2005 AHA Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care" contain recommendations designed to improve survival from sudden cardiac arrest and acute life-threatening cardiopulmonary problems. The evidence evaluation process that was the basis for these guidelines was accomplished in collaboration with the International Liaison Committee on Resuscitation (ILCOR). The ILCOR process is described in more detail in the "International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations." The recommendations in the "2005 AHA Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care" confirm the safety and effectiveness of many approaches, acknowledge that other approaches may not be optimal, and recommend new treatments that have undergone evidence evaluation. These new recommendations do not imply that care involving the use of earlier guidelines is unsafe. In addition, it is important to note that these guidelines will not apply to all rescuers and all victims in all situations. The leader of a resuscitation attempt may need to adapt application of the guidelines to unique circumstances. The following are the major pediatric advanced life support changes in the 2005 guidelines: There is further caution about the use of endotracheal tubes. Laryngeal mask airways are acceptable when used by experienced providers. Cuffed endotracheal tubes may be used in infants (except newborns) and children in in-hospital settings provided that cuff inflation pressure is kept <20 cm H2O. Confirmation of tube placement requires clinical assessment and assessment of exhaled carbon dioxide (CO2); esophageal detector devices may be considered for use in children weighing >20 kg who have a perfusing rhythm. Correct placement must be verified when the tube is inserted, during transport, and whenever the patient is moved. During CPR with an advanced airway in place, rescuers will no longer perform "cycles" of CPR. Instead, the rescuer performing chest compressions will perform them continuously at a rate of 100/minute without pauses for ventilation. The rescuer providing ventilation will deliver 8 to 10 breaths per minute (1 breath approximately every 6-8 seconds). Timing of 1 shock, CPR, and drug administration during pulseless arrest has changed and now is identical to that for advanced cardiac life support. Routine use of high-dose epinephrine is not recommended. Lidocaine is de-emphasized, but it can be used for treatment of ventricular fibrillation/pulseless ventricular tachycardia if amiodarone is not available. Induced hypothermia (32-34 degrees C for 12-24 hours) may be considered if the child remains comatose after resuscitation. Indications for the use of inodilators are mentioned in the postresuscitation section. Termination of resuscitative efforts is discussed. It is noted that intact survival has been reported following prolonged resuscitation and absence of spontaneous circulation despite 2 doses of epinephrine. The following are the major neonatal resuscitation changes in the 2005 guidelines: Supplementary oxygen is recommended whenever positive-pressure ventilation is indicated for resuscitation; free-flow oxygen should be administered to infants who are breathing but have central cyanosis. Although the standard approach to resuscitation is to use 100% oxygen, it is reasonable to begin resuscitation with an oxygen concentration of less than 100% or to start with no supplementary oxygen (ie, start with room air). If the clinician begins resuscitation with room air, it is recommended that supplementary oxygen be available to use if there is no appreciable improvement within 90 seconds after birth. In situations where supplementary oxygen is not readily available, positive-pressure ventilation should be administered with room air. Current recommendations no longer advise routine intrapartum oropharyngeal and nasopharyngeal suctioning for infants born to mothers with meconium staining of amniotic fluid. Endotracheal suctioning for infants who are not vigorous should be performed immediately after birth. A self-inflating bag, a flow-inflating bag, or a T-piece (a valved mechanical device designed to regulate pressure and limit flow) can be used to ventilate a newborn. An increase in heart rate is the primary sign of improved ventilation during resuscitation. Exhaled CO2 detection is the recommended primary technique to confirm correct endotracheal tube placement when a prompt increase in heart rate does not occur after intubation. The recommended intravenous (IV) epinephrine dose is 0.01 to 0.03 mg/kg per dose. Higher IV doses are not recommended, and IV administration is the preferred route. Although access is being obtained, administration of a higher dose (up to 0.1 mg/kg) through the endotracheal tube may be considered. It is possible to identify conditions associated with high mortality and poor outcome in which withholding resuscitative efforts may be considered reasonable, particularly when there has been the opportunity for parental agreement. The following guidelines must be interpreted according to current regional outcomes: When gestation, birth weight, or congenital anomalies are associated with almost certain early death and when unacceptably high morbidity is likely among the rare survivors, resuscitation is not indicated. Examples are provided in the guidelines. In conditions associated with a high rate of survival and acceptable morbidity, resuscitation is nearly always indicated. In conditions associated with uncertain prognosis in which survival is borderline, the morbidity rate is relatively high, and the anticipated burden to the child is high, parental desires concerning initiation of resuscitation should be supported. Infants without signs of life (no heartbeat and no respiratory effort) after 10 minutes of resuscitation show either a high mortality rate or severe neurodevelopmental disability. After 10 minutes of continuous and adequate resuscitative efforts, discontinuation of resuscitation may be justified if there are no signs of life.

Management der oberen Atemwege beim spontan atmenden Kind

In unconscious, spontaneously breathing and anaesthetised children, a high incidence of partial or complete airway obstruction jeopardizes sufficient oxygenation. In this situation, the most important and efficient manoeuvre is to open up the upper airway. Chin lift, jaw thrust and continuous positive airway pressure (CPAP) are proven and effective methods for opening an obstructed upper airway. In addition to these simple airway manoeuvres, different techniques of body positioning (e.g., lateral positioning or supine position in combination with the "sniffing position") are effective to improve and maintain upper airway patency.

Obstructive Sleep Apnea Syndrome in Children

Obstructive sleep apnea syndrome is characterized by recurrent episodes of partial or complete obstruction of the upper airway during sleep. This results in the disruption of normal ventilation and sleep patterns. The symptoms, polysomnographic findings, pathophysiology, and treatment of obstructive sleep apnea syndrome are significantly different in children from those seen in adults.

The Endoscopically Measured Effects of Airway Maneuvers and the Lateral Position on Airway Patency in Anesthetized Children with Adenotonsillar Hypertrophy

Obstruction of the upper airway is a major challenge for anesthesiologists administering general anesthesia in spontaneously breathing children with adenotonsillar hypertrophy. Lateral positioning is a simple treatment for obstructive sleep apnea. In this study, we examined the effects of body position shifting and common airway maneuvers such as chin lift and jaw thrust on airway patency (stridor score and upper airway dimensions by endoscopy) in anesthetized children scheduled for adenotonsillectomy. Eighteen children aged 1-11 yr were anesthetized with sevoflurane. During spontaneous breathing with 5% sevoflurane and 100% oxygen, upper airway dimensions and stridor score were recorded. After baseline recording, chin lift and jaw thrust were performed in both the supine and the lateral decubitus position. Chin lift, jaw thrust, and lateral position increased the airway dimensions and improved the stridor score. Moreover, lateral positioning enhanced the effects of these airway maneuvers on airway patency. We concluded that lateral positioning combined with airway maneuvers provided better airway patency for anesthetized children with adenotonsillar hypertrophy.

Jaw thrust can deteriorate upper airway patency

Upper airway obstruction is a frequent problem in spontaneously breathing children undergoing anesthesia or sedation procedures. Failure to maintain a patent airway can rapidly result in severe hypoxemia, bradycardia, or asystole, as the oxygen demand of children is high and oxygen reserve is low. We present two children with cervical masses in whom upper airway obstruction exaggerated while the jaw thrust maneuver was applied during induction of anesthesia. This deterioration in airway patency was probably caused by medial displacement of the lateral tumorous tissues which narrowed the pharyngeal airway.

The Effects of Chin Lift and Jaw Thrust While in the Lateral Position on Stridor Score in Anesthetized Children with Adenotonsillar Hypertrophy

Obstruction of the upper airway is a major challenge for anesthesiologists administering general anesthesia in spontaneously breathing patients, especially in pediatric anesthesia with adenotonsillar hypertrophy. Lateral positioning is a simple treatment for obstructive sleep apnea and also decreases collapsibility of the pharynx in anesthetized adults with obstructive sleep apnea. In this study, we examined the effects of body position shifting and common airway maneuvers, such as chin lift and jaw thrust, on airway patency (stridor score) in anesthetized children scheduled for adenotonsillectomy. Thirty children aged 1-10 yr were anesthetized with sevoflurane. During spontaneous breathing of 5% sevoflurane, stridor score was recorded. After baseline recording, chin lift and jaw thrust were performed on patients in both the supine and the lateral decubitus positions. Chin lift and jaw thrust improved the stridor score. Furthermore, lateral positioning dramatically enhanced the effects of these airway maneuvers on airway patency. Jaw thrust combined with lateral positioning provided easy airway management for the anesthesiologists. We conclude that lateral positioning combined with airway maneuvers significantly improved airway patency compared with the airway maneuvers alone for patients in the supine position.

The pediatric airway

Good airway management technique is an essential skill for physicians in most specialties. This article begins with a review of basic airway anatomy and the physiology of the uninstrumented airway. This subject is of particular importance given the increasing use of procedural sedation and the increased recognition of sleep-disordered breathing in infants and children. A discussion of the various artificial airways and their advantages and disadvantages follows. The difficult airway is an important contributor to both patient morbidity and mortality. It is important to have a planned management approach available for the anticipated and, more importantly, the unanticipated difficult airway. The recommendations of the American Society of Anesthesiologists Taskforce on the Management of the Difficult Airway have good application for this important problem. The fetus with the prenatal diagnosis of a lesion that predicts a difficult airway presents a particular challenge. The utilization of an ex-utero intrapartum treatment method is presented as an important approach for the delivery and airway management of these infants. This section closes with a discussion of the prehospital airway management of the pediatric patient.

The paediatric upper airway: anaesthetic aspects and conclusions

PURPOSE OF REVIEW

Paediatric airway problems are among the most challenging clinicians will face throughout their career. Clinicians unaccustomed to dealing with children tend to approach paediatric airway problems with a disproportionate amount of fear that is often engendered by inexperience, and this fear can interfere with performance. Understanding the differences between the infant upper airway and the airway in older children is important to properly manage the airway.

RECENT FINDINGS

Airway manoeuvres and the important tools used for airway management, such as the laryngeal mask airway, the fibreoptic bronchoscope and the new intubating fibreoptic stylets for managing the difficult paediatric airway, have been elucidated in the literature.

SUMMARY

Planning, preparation, and teamwork are essential, and must include an awareness of problems that might occur in the recovery period. Special clinical situations such as management of the child with impending airway obstruction are discussed.