Dental trauma associated with anaesthesia

The Callender modification of the Macintosh laryngoscope blade reduces the risk of tooth-blade contact in children

BACKGROUND

Dental injury is well recognized as a potential complication of laryngoscopy and tracheal intubation. The flange of the Macintosh blade may contact teeth during laryngoscopy causing damage. The Callander modification of the Macintosh blade (Callander blade) with a shortened heel at the proximal end has been shown to increase the blade-tooth distance and reduce contact rates in adults.

AIM

This study was designed to evaluate the effectiveness of the Callander blade on reducing dental contact in children.

METHODS

One hundred children, aged 4-14 years, scheduled for general anesthesia requiring endotracheal intubation were studied prospectively. The children were preoperatively evaluated for Mallampati score and dental defects, looseness, and avulsions. Following induction of anesthesia, laryngoscopy was performed twice on each child in succession, once with a standard Macintosh blade and once with a Callander blade of the same size in a random order. The blade-tooth distance and contact rate were compared between the two blades.

RESULTS

With the Callander blade, the blade-tooth distance was greater than with the Macintosh (1.78 +/- 1.77 vs 0.28 +/- 0.76 mm, P = 0.001). The frequency of direct contact was less with the Callander blade than it was with the Macintosh blade (33% vs 86%, respectively, P = 0.008). However, difficult laryngoscopy rate did not differ between the blades. Tracheal intubation was successful in all children and there was no dental injury.

CONCLUSION

Our findings suggest that the Callander blade decreases the risk for dental injury and provides tracheal intubating conditions in children with normal airways similar to those obtained with a traditional Macintosh blade.

Dental injury associated with anesthesia: a report of 161,687 anesthetics given over 14 years

STUDY OBJECTIVE

To determine the frequency, outcomes, and risk factors for dental injury related to anesthesia.

DESIGN

Case-control study.

SETTING

Tertiary-care university hospital.

PATIENTS

Patients who had a perianesthetic dental injury between August of 1989 and December 31, 2003.

MEASUREMENTS

A 1:2 case control study was done to identify the frequency, outcomes, and risk factors for dental injury. Perianesthetic dental injuries were defined as any notable change to the patient's dentition during the perianesthetic period that may or may not have required dental consultation or treatment.

MAIN RESULTS

Seventy-eight patients with perianesthetic dental injury were identified. The incidence of dental injury was one per 2,073 anesthetics. Eighty-six percent of dental injuries were discovered by the anesthesia provider. Maxillary incisors were the most frequently injured teeth. The most commonly reported injuries were enamel fracture, loosened or subluxated teeth, tooth avulsion, and crown or root fracture. Patients with poor dentition or reconstructive work, whose tracheas were moderately difficult or difficult to intubate, were at much higher risk (approximately 20-fold) of dental injury than those with good dentition and found to be easy to intubate. Among those whose tracheas were easy to intubate, patients with poor dentition or reconstructive work were 3.4 times more likely to have dental injuries related to anesthesia.

CONCLUSIONS

Dental injury is one of the most common adverse events reported in association with anesthesia. Risk factors include preexisting poor dentition or reconstructive work and moderately difficult to difficult intubation.

Complications associated with the use of the GlideScope videolaryngoscope

PURPOSE

Two cases are presented wherein the GlideScope videolaryngoscope (GVL) facilitated laryngeal exposure and successful endotracheal intubation, but resulted in pharyngeal injury.

CLINICAL FEATURES

GlideScope videolaryngoscopy was performed in two female patients, whose airways were anticipated to present difficulties for direct laryngoscopy. In the first case, following induction of anesthesia, moderate difficulty was encountered in directing the endotracheal tube (ETT) into the patient's larynx. In the second case, minimal difficulty with the GVL was experienced, and no problems were identified with airway instrumentation until the drapes covering the patient's face were removed. In both instances, the ETT had passed through the right palatopharyngeal arch, requiring suturing in the first patient, and electrocautery in the second patient.

CONCLUSION

There have been no previously published reports of injuries related to GlideScope laryngoscopy, but perforation of the palatopharyngeal arch occurring in two patients demonstrates a rare but potentially important complication of the GVL. Strategies to minimize this complication are considered.

Lower flange modification improves performance of the Macintosh, but not the Miller laryngoscope blade

PURPOSE

In order to minimize the potential for dental damage and to improve laryngeal visualization during tracheal intubation, two commonly used laryngoscope blades were modified and compared in a clinical setting: the Miller laryngoscope blade and the Macintosh laryngoscope blade. Modified versions of both laryngoscope blades with a lowered heel (Callander modification) at the proximal end of the blade were compared to standard blades.

METHODS

Forty patients scheduled for general anesthesia requiring endotracheal intubation were studied prospectively. Preoperatively, the patients' airways were evaluated according to Mallampati score, thyromental distance and interincisor gap. After induction of anesthesia laryngoscopy was performed with the original laryngoscope and its modified counterpart in random order. A lateral x-ray of the neck was taken after the optimal view had been obtained, and blade-tooth distance, laryngeal view, blade-tooth contact and need for assistance were measured. Using angular calculations the laryngoscopes were analyzed at different insertion depths on graph paper, and the results were compared with data from the lateral x-rays.

RESULTS

With a modified Macintosh blade the blade-tooth distance was significantly greater in comparison to the original design (2.5 +/- 2.1 cm vs 0.2 +/- 0.1 cm, P < 0.01). Consequently the number of blade-tooth contacts was significantly lower (20% vs 75%, P < 0.05). The best laryngeal view could be obtained using a modified Macintosh laryngoscope. With a modified Miller laryngoscope laryngeal visibility was not improved and assistance was required more often to achieve adequate intubating conditions (35% vs 5%, P < 0.05).

CONCLUSION

A reduction of the proximal flange of a Miller blade decreases the blade's effectiveness for laryngeal visualization, whereas a similar modification of a Macintosh blade increases blade-tooth distance, decreases the number of blade-tooth contacts and provides a better laryngeal view.

The usefulness of the modified laryngoscopic blade for training novice laryngoscopists

STUDY OBJECTIVE

The objective of this study was to evaluate the effectiveness of a modified Macintosh blade for reducing the chances of directly contacting the teeth and providing a satisfactory laryngoscopic view during laryngoscopies by novice laryngoscopists.

DESIGN

This is a prospective clinical comparison study.

SETTING

The study took place at an operating room of a university hospital.

PATIENTS

Seventy-two patients with American Society of Anesthesiologists physical statuses I and II, aged 16 to 64 years, who were scheduled for elective surgery requiring general anesthesia with endotracheal tube placement participated in this study.

INTERVENTIONS

Laryngoscopy was performed twice on each patient, once with a regular Macintosh no. 3 blade and once with a blade in which the flange was partially removed.

MEASUREMENTS

As an indirect parameter for anticipating potential dental injury during laryngoscopy, the perpendicular distance from the tip of the maxillary central incisor to the flange of each blade (the blade-tooth distance) was measured when a novice laryngoscopist lifted up the laryngoscope and visualized the glottis. We compared the blade-tooth distances, the chances of directly contacting the tooth, laryngoscopic views, and the subjective feeling of difficulty in handling the laryngoscope between the 2 blades.

MAIN RESULTS

Blade-tooth distance varied significantly between the 2 blades: the median/interquartile range was 1.2/2.3 mm vs 3.0/4.3 mm for the regular Macintosh no. 3 and the modified blade, respectively (P<.01). The modified blade was associated with decreased chances of directly contacting the teeth (P<.05). In addition, the modified blade provided a better laryngoscopic view than did the regular blade (P<.01). Most novice laryngoscopists felt that laryngoscopy with the modified blade was significantly easier than that with the regular Macintosh blade (P<.01).

CONCLUSIONS

The modified Macintosh blade used in this study proved to be a useful device for training novice laryngoscopists with respect to procedure effectiveness and patient safety.

Delayed obstruction of endotracheal tubes by aspirated foreign bodies: report of two cases

We present 2 cases of endotracheal tube obstruction as a result of previously aspirated foreign bodies that moved from the bronchial tree into the endotracheal tube. The signs of endotracheal tube obstruction were demonstrated in both cases: (1) activation of the high-pressure alarm; (2) difficulty ventilating by using a bag-valve-mask device; (3) rapid decrease of end-tidal CO2; (4) oxygen desaturation that may have lagged behind the decrease of end-tidal CO2; and (5) the inability to advance a catheter down the endotracheal tube. The differential diagnosis of endotracheal tube obstruction is discussed, as are possible interventions to remove the obstruction and secure an open airway.

The callander laryngoscope blade modification is associated with a decreased risk of dental contact

PURPOSE

Dental damage may occur with laryngoscopy. The purpose of this study was twofold: to determine whether preoperative examination could predict the risk of contacting the teeth with the laryngoscope and to evaluate the effectiveness of a modified Macintosh blade on reducing dental contact.

METHODS

Four hundred and eighty-three patients scheduled for elective surgery requiring general anesthesia with endotracheal tube placement were studied prospectively. Features that might predict difficult intubation were assessed preoperatively. Laryngoscopy was performed twice on each patient, once with a regular Macintosh 3 blade and once with a blade in which the flange was partially removed (Callander modification). The distance between the flange of the blade and the upper incisors at glottic exposure was measured. We calculated correlations between individual airway characteristics and the chance of hitting the upper teeth with the regular Macintosh 3 blade and compared the frequencies of contacting the teeth between the two blades.

RESULTS

The chance of hitting the upper teeth when using the regular Macintosh 3 blade increased significantly with non-parametric scores for Mallampati classification, mandibular subluxation, head and neck movement, interincisor gap, and condition of the upper teeth. (P < 0.01) The frequency of direct contact varied significantly between the two blades: 20.3% vs 4.1% for Macintosh 3 and modified blades, respectively (P < 0.05). Laryngeal views were improved with the modified blade.

CONCLUSION

Airway characteristics correlate with the risk of hitting the upper teeth during laryngoscopy. The modified Macintosh blade reduces the risk of contacting the teeth.

Do Women Simply Complain More? National Patient Injury Claims Data Show Gender and Age Differences

The Swedish Counties Mutual Insurance (LOF) owns and operates the Swedish Patient Insurance Company, (PSR) a no-blame insurance system that compensates patients for injuries that result from errors in medical practice. We combined malpractice claims data (from PSR) with national hospital discharge registry data (National Board of Health and Welfare-Socialstyrelsen) and determined Swedish inpatient malpractice claims rates for the years 1996-2000. Women have higher claims rates than men, but their claims are adjudicated as valid more often than men's claims. The data are consistent with other lines of evidence suggesting poorer quality of care for women, e.g., heart disease, kidney disease, and cancer. Middle-aged (40- to 59-year-old) patients file malpractice claims at almost twice the national rate, whereas patients younger than 19 years and older than 80 years of age file at significantly below the average rate. Differences in claims rates have major financial and quality of care implications. Further studies are needed.

[Lesions to lips, oral and nasal cavities, pharynx, larynx, trachea and esophagus due to endotracheal intubation and its alternatives]

Dysphagia of greater than 48 h duration is an indication for indirect laryngoscopy and when odynophagia and otalgia occur simultaneously, the possibility of subluxation of the arytenoids demands an urgent ENT assessment. The potential seriousness of laryngeal lesions following intubation obliges us to use the smallest compatible endotracheal tube. The occurrence of pain cervical surgical emphysema and fever suggests a pharyngeal lesion necessitating the suspension of oral feeding and the initiation of antibiotic therapy with anaerobic activity, while awaiting possible surgical intervention. There is no argument to use a tooth-guard for each intubation, but tooth fragility must be researched. The incidence of nasal fossa trauma is reduced with the use of nasal packs impregnated with local anaesthetic containing a vasoconstrictor. This allows the introduction of a small flexible lubricated tube. Laryngeal mask-induced sore throat is more common than the more serious injuries. The classical technique of introducing a laryngeal mask of appropriate size (4 for women, 5 for men) in which the cuff is inflated to a leak pressure of 20 cm H(2)O reduces this frequency. The facial mask may cause injuries especially with prolonged use. The incidence of pulmonary aspiration, linked to the action of drugs, raised intra-abdominal pressure; an emergent situation or difficult intubation is decreased with the performance of the Sellick maneuver at intubation, rapid induction and the neutralization of gastric acidity. A meticulous technique of insertion of the, individualized anaesthesia, particular vigilance at the time of decurarisation and position changes and a calm awakening assure its optimal use, unless the Proseal laryngeal mask modifies this point of view.

A standardized, uniform and universal dental chart for documenting state of dentition before anaesthesia

It is vital to have adequate and precise documentation of the condition of a patient's dentition before commencing an anaesthetic. The incidence of dental damage during anaesthesia is not low. To the authors' knowledge, there is no standardized method used by anaesthetists to document the state of a patient's dentition. We propose the introduction of a standardized uniform dental chart to enable anaesthetists to accurately document the condition of their patients' teeth. This vital information can be easily obtained during the preanaesthetic assessment. With the increase in medical litigation and demands for adequate documentation, we believe this chart can become an invaluable part of every hospital's preanaesthetic assessment form. The dental chart is to be offered as a service to anaesthetists in the form of a copyright-free "Freeware" computer diskette or adhesive sticker and will be downloadable from the internet.