Risk factors for intubation injury of the larynx

Otolaryngologic Symptom Severity Post SARS-CoV-2 Infection

Objective(s)

To assess laryngologic symptomatology following SARS-CoV-2 infection and determine whether symptom severity correlates with disease severity.

Methods

Single-institution survey study in participants with documented SARS-CoV-2 infection between March 2020 and February 2021. Data acquired included demographic, infection severity characteristics, comorbidities, and current upper aerodigestive symptoms via validated patient reported outcome measures.  Primary outcomes of interest were scores of symptom severity questionnaires. COVID-19 severity was defined by hospitalization status. Descriptive subgroup analyses were performed to investigate differences in demographics, comorbidities, and symptom severity in hospitalized participants stratified by ICU status. Multivariate logistical regression was used to evaluate significant differences in symptom severity scores by hospitalization status.

Results

Surveys were distributed to 5300 individuals with upper respiratory infections. Ultimately, 470 participants with COVID-19 were included where 352 were hospitalized and 118 were not hospitalized. Those not hospitalized were younger (45.87 vs. 56.28 years), more likely female (74.17 vs. 58.92%), and less likely white (44.17 vs. 52.41%). Severity of dysphonia, dyspnea, cough, and dysphagia was significantly worse in hospitalized patients overall and remained worse at all time points. Cough severity paradoxically worsened in hospitalized respondents over time. Dyspnea scores remained abnormally elevated in respondents even 12 months after resolution of infection.

Conclusion

Results indicate that laryngologic symptoms are expected to be worse in patients hospitalized with COVID-19. Dyspnea and cough symptoms can be expected to persist or even worsen by one-year post infection in those who were hospitalized. Dysphagia and dysphonia symptoms were mild. Non-hospitalized participants tended to have minimal residual symptoms by one year after infection.

Laryngeal injury following endotracheal intubation: Have you considered reflux?

Laryngotracheal injury is an increasingly common complication of intubation and mechanical ventilation, with an estimated 87% of intubated and ventilated patients developing a laryngotracheal injury often preventing their rehabilitation from acute illness. Laryngotracheal injuries encompass a diverse set of pathologies including inflammation and oedema in addition to vocal cord ulceration and paralysis, granuloma, stenosis, and scarring. The existing literature has identified several factors including intubation duration, endotracheal tube size, type and cuff pressures, and technical factors including the skill and experience of the endoscopist. Despite these associations, a key aspect in the sequelae of laryngotracheal injuries is due to reflux and is not clearly related to iatrogenic and mechanical factors.Laryngopharyngeal reflux is a type of reflux that contaminates the upper aerodigestive tract. The combination of patient positioning and continuous nasogastric tube feeding act to affect the upper aerodigestive tract with acidic and non-acidic refluxate that causes direct and indirect mucosal injury impeding healing.Despite laryngopharyngeal reflux being an established and recognised causative factor of upper aerodigestive tract inflammatory pathology and laryngotracheal injury, it is very understudied in critical care. Further, there is yet to be an agreed pathway to assess, manage and prevent laryngotracheal injury in intubated and ventilated patients. The incidence of laryngopharyngeal reflux in the intubated and mechanically ventilated patient in the intensive care unit is currently unknown. Prospective studies may allow us to understand further potential mechanisms of upper aerodigestive tract injury due to laryngopharyngeal reflux and herald the development of preventative and management strategies of laryngopharyngeal reflux-mediated upper aerodigestive tract injury in critically ill patients.

A Novel Surgical Technique for Posterior Glottic Stenosis Using a Silastic Implant

OBJECTIVES

To introduce a novel surgical technique for the management of posterior glottic stenosis (PGS).

METHODS

Literature review (PubMed 1973-2020) and case example of a patient treated with novel technique by principal investigator (R.T.S.) RESULTS: Numerous techniques for the treatment of PGS have had varying success. Our patient, a 67-year-old male with a 2-year history of posterior glottic stenosis secondary to multiple, prolonged intubations previously had been treated with several surgical and medical interventions. Three weeks following an additional endotracheal intubation, he presented to our office with PGS recurrence, exhibiting hoarseness, and shortness of breath with any physical activity. He was treated with a silastic sheet placed through a tunnel in the stenosis and sutured posteriorly as a stent. The stent was removed 3 weeks later and the remaining stenosis was divided, successfully treating our patient's PGS with long-term improvement in both respiratory and voice complaints. This led to the design of a stent to be used for this purpose.

CONCLUSIONS

This new surgical technique addresses a complex clinical problem and provides otolaryngologists with a minimally invasive option for the surgical treatment of PGS that offers advantages over existing techniques. The two-stage procedure should reduce the risk of recurrence, but more experience is needed. This novel implant may be a valuable tool in the treatment of select patients with mild-moderate PGS.

Airway injury from the presence of endotracheal tubes and the association with subglottic secretion drainage: a prospective observational study

PURPOSE

Laryngeal and tracheal injuries are known complications of endotracheal intubation. Endotracheal tubes (ETTs) with subglottic suction devices (SSDs) are commonly used in the critical care setting. There is concern that herniation of tissue into the suction port of these devices may lead to tracheal injury resulting in serious clinical consequences such as tracheal stenosis. We aimed to describe the type and location of tracheal injuries seen in intubated critically ill patients and assess injuries at the suction port as well as in-hospital complications associated with those injuries.

METHODS

We conducted a prospective observational study of 57 critically ill patients admitted to a level 3 intensive care unit who were endotracheally intubated and underwent percutaneous tracheostomy. Investigators performed bronchoscopy and photographic evaluation of the airway during the percutaneous tracheostomy procedure to evaluate tracheal and laryngeal injury.

RESULTS

Forty-one (72%) patients intubated with ETT with SSD and sixteen (28%) patients with standard ETT were included in the study. Forty-seven (83%) patients had a documented airway injury ranging from hyperemia to deep ulceration of the mucosa. A common tracheal injury was at the site of the tracheal cuff. Injury at the site of the subglottic suction device was seen in 5/41 (12%) patients. There were no in-hospital complications.

CONCLUSIONS

Airway injury was common in critically ill patients following endotracheal intubation, and tracheal injury commonly occurred at the site of the endotracheal cuff. Injury occurred at the site of the subglottic suction port in some patients although the clinical consequences of these injuries remain unclear.

Novel expandable architected breathing tube for improving airway securement in emergency care

Life-saving interventions utilize endotracheal intubation to secure a patient's airway, but performance of the clinical standard of care endotracheal tube (ETT) is inadequate. For instance, in the current COVID-19 crisis, patients can expect prolonged intubation. This protracted intubation may produce health complications such as tracheal stenosis, pneumonia, and necrosis of tracheal tissue, as current ETTs are not designed for extended use. In this work, we propose an improved ETT design that seeks to overcome these limitations by utilizing unique geometries which enable a novel expanding cylinder. The mechanism provides a better distribution of the contact forces between the ETT and the trachea, which should enhance patient tolerability. Results show that at full expansion, our new ETT exerts pressures in a silicone tracheal phantom well within the recommended standard of care. Also, preliminary manikin tests demonstrated that the new ETT can deliver similar performance in terms of air pressure and air volume when compared with the current gold standard ETT. The potential benefits of this new architected ETT are threefold, by limiting exposure of healthcare providers to patient pathogens through streamlining the intubation process, reducing downstream complications, and eliminating the need of multiple size ETT as one architected ETT fits all.

Diabetes in the practice of otolaryngology

Diabetes mellitus is the most common endocrine disease, characterized by chronic hyperglycemia. The hyperglycemic milieu leads to endothelial injury in blood vessels of variant size, which results in microangiopathy and macroangiopathy (atherosclerosis). Consequential ischemia of nerves and hyperglycemia by itself lead to nerve degeneration and generalized neuropathy, affecting most often the sensory peripheral nerves and the autonomic nervous system. Auditory, vestibular and olfactory sensorium may be compromised by DM. People with DM have an increased susceptibility to infection, as a result of neutrophil dysfunction and impaired humoral immunity. Therefore DM predisposes to certain infectious diseases, such as fungal sinusitis or malignant otitis externa, which are rare in general population. Recovery from infections or from injuries may be compromised by coexisting DM. In this review we discuss complications of DM in the head and neck region. Otolaryngologists and general practitioners should be alert to specific conditions related to DM and be minded of the relevant complications and consequences.

Laryngeal Injury and Upper Airway Symptoms After Oral Endotracheal Intubation With Mechanical Ventilation During Critical Care: A Systematic Review

OBJECTIVES

To systematically review the symptoms and types of laryngeal injuries resulting from endotracheal intubation in mechanically ventilated patients in the ICU.

DATA SOURCES

PubMed, Embase, CINAHL, and Cochrane Library from database inception to September 2017.

STUDY SELECTION

Studies of adult patients who were endotracheally intubated with mechanical ventilation in the ICU and completed postextubation laryngeal examinations with either direct or indirect visualization.

DATA EXTRACTION

Independent, double-data extraction and risk of bias assessment followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Risk of bias assessment followed the Cochrane Collaboration's criteria.

DATA SYNTHESIS

Nine studies (seven cohorts, two cross-sectional) representing 775 patients met eligibility criteria. The mean (SD; 95% CI) duration of intubation was 8.2 days (6.0 d; 7.7-8.7 d). A high prevalence (83%) of laryngeal injury was found. Many of these were mild injuries, although moderate to severe injuries occurred in 13-31% of patients across studies. The most frequently occurring clinical symptoms reported post extubation were dysphonia (76%), pain (76%), hoarseness (63%), and dysphagia (49%) across studies.

CONCLUSIONS

Laryngeal injury from intubation is common in the ICU setting. Guidelines for laryngeal assessment and postextubation surveillance do not exist. A systematic approach to more robust investigations could increase knowledge of the association between particular injuries and corresponding functional impairments, improving understanding of both time course and prognosis for resolution of injury. Our findings identify targets for future research and highlight the long-known, but understudied, clinical outcomes from endotracheal intubation with mechanical ventilation in ICU.

Analysis of Age-Related Differences of Risk Factors and Comorbidities in Laryngotracheal Stenosis Patients

Laryngotracheal stenosis (LTS) is a life threatening airway problem that is mainly caused by prolonged intubation. The authors intend to assess whether there was variability in the risk factors depending on age, and to determine which risk factors and comorbidities were more important in the development of LTS at older or younger ages. Fifty-two LTS patients were evaluated for comorbidities and risk factors retrospectively. The LTS etiologies, demographics, and medical and surgical histories of the patients were determined by the medical records. The patients under 40 years old were defined as group 1, and the patients 40 years of age or older were defined as group 2. Our study revealed that with regard to GERD, hypertension, DM2, and pulmonary infection, there was a statistically significant difference between group 1 and group 2 (p = 0.025, p = 0.0005, p = 0.002, and p = 0.000, respectively). Those patients ≥ 40 years old exhibited higher rates of GERD, hypertension, DM2, and pulmonary infection. However, there were no statistically significant differences between the groups with regard to smoking, alcohol consumption, COPD/asthma, immunological disease, and obesity (BMI > 30). There was a statistically significant difference between the groups for all the risk factors except a previous tracheotomy (p = 0.115). The risk factors and comorbidities thought to be involved in the development of LTS could show age-related variability. Therefore, in patients over 40 years of age with comorbidities (GERD, hypertension, DM2, and pulmonary infection), it is necessary to take precautions before the development of LTS. Prolonged intubation and tracheotomy history are the main risk factors for all patients, regardless of age.

Tracheostomy in the ICU

The placement of a tracheostomy has become a routine procedure for intensive care unit patients who are mechanical ventilator dependent for a period of time, usually exceeding 1 or 2 weeks. It is vital for the intensivist to be familiar with all aspects of tracheostomies care including the timing of converting a patient to a tracheostomy, types of procedure, risks and benefits, and issues of daily care including oral feedings, speech, and decannulation. In this article we provide a comprehensive review for the intensivist regarding tracheostomies in the intensive care setting. We specifically review indications, timing, surgical options including percutaneous dilation tracheostomy, complications, decannulation, oral feeding, speaking devises, stomal stents, and routine tracheostomy care.

Predictors of Posterior Glottic Stenosis: A Multi-Institutional Case-Control Study

OBJECTIVE

To assess intrinsic and extrinsic risk factors in the development of posterior glottic stenosis (PGS) in intubated patients.

METHODS

Patients diagnosed with PGS between September 2012 and May 2014 at 3 tertiary care university hospitals were included. Patient demographics, comorbidities, duration of intubation, endotracheal tube (ETT) size, and indication for intubation were recorded. Patients with PGS were compared to control patients represented by patients intubated in intensive care units (ICU).

RESULTS

Thirty-six PGS patients were identified. After exclusion, 28 PGS patients (14 male, 14 female) and 112 (65 male, 47 female) controls were studied. Multivariate analysis demonstrated ischemia (P < .05), diabetes (P < .01), and length of intubation (P < .01) were significant risk factors for the development of PGS. Fourteen of 14 (100%) males were intubated with a size 8 or larger ETT compared to 47 of 65 (72.3%) male controls (P < .05). Posterior glottic stenosis (P < .01), length of intubation (P < .001), and obstructive sleep apnea (P < .05) were significant risk factors for tracheostomy.

CONCLUSION

Duration of intubation, ischemia, diabetes mellitus, and large ETT size (8 or greater) in males were significant risk factors for the development of PGS. Reducing the use of size 8 ETTs and earlier planned tracheostomy in high-risk patients may reduce the incidence of PGS and improve ICU safety.

Acquired Glottic Stenosis-The Ongoing Challenge: A Review of Etiology, Pathogenesis, and Surgical Management

OBJECTIVE

To review the etiology and pathogenesis of acquired glottic stenosis, as well as the workup, patient preparation, interventional options, and their changing trends, as described in the literature since the 19th century until the present day.

METHODS

Literature from the PubMed search engine and the authors' personal experience were used. The search included up to date studies and historical reports covering different aspects of glottic stenosis, such as basic science, pathogenesis, anesthesia, and surgical techniques.

RESULTS

At present, the most common etiology for acquired glottic stenosis is damage to the posterior commissure after intubation. Until less than a century ago, infectious diseases such as diphtheria and syphilis were the most prevalent etiologies. The common pathway of stenosis includes mucosal and cartilaginous ulcers, granulation formation, fibrosis, and tethering scars. Planning of surgical intervention must begin with the matching of expectations with the patient and considering voice versus airway functions. Preoperative tracheotomy should be considered for securing the airway. Anesthesia has to be carefully planned, and both the surgeon and the anesthesiologist have to be familiar with the options for tubeless jet ventilation. Surgical options include a variety of open and endoscopic resection and reconstruction procedures, which are reviewed in this article, followed by images and illustrations based on the authors' experience.

CONCLUSION

Acquired glottic stenosis compromises the breathing, voice production, and airway protection. Reconstructing the stenosed glottis is one of the major challenges facing laryngologists in this era. For this reason, the surgeon must be familiar with the variety of treatment options.

A simple mechanical device reduces subglottic injury in ventilated animals

OBJECTIVES/HYPOTHESIS

To test whether a simple inexpensive device that dynamically minimizes endotracheal cuff pressure throughout the respiratory cycle reduces endotracheal cuff pressure-related subglottic injury.

STUDY DESIGN

Hypoxic animal model with one control and one experimental group.

METHODS

Twelve S. scrofa domesticus piglets (14-16 kg) were intubated with standard endotracheal tubes and maintained in a hypoxic state to accelerate airway injury. Animals in the control group (n = 6) were ventilated with a constant pressure of 20 cm H₂O in the endotracheal tube cuff. Animals in the experimental group (n = 6) were ventilated using a custom-designed circuit that altered the pressure in the endotracheal tube cuff in synchrony with the ventilatory cycle. Larynges were harvested at the end of the experiment and examined histologically to determine the degree of airway injury induced by the endotracheal cuff.

RESULTS

Animals in the experimental group suffered significantly less airway damage than those in the control group. The differences were seen primarily in the subglottis (aggregate damage score 6.5 vs. 12, P <0.05), where the experimental endotracheal tube cuff exerted the least pressure. There was no difference in damage to the glottic or supraglottic structures.

CONCLUSIONS

A simple, reliable, and inexpensive means of modulating endotracheal tube cuff pressure with the ventilatory cycle led to a substantial decrease in airway injury in our animal model. Such reduction in cuff pressure may prove important for humans, particularly those in intensive care units who tend to have underlying conditions predisposing them to tracheal damage from the endotracheal tube cuff.

Laryngeal complications by orotracheal intubation: Literature review

INTRODUCTION

 The injuries caused for the orotracheal intubation are common in our way and widely told by literature. Generally the pipe rank of or consequence of its permanence in the aerial ways of the patient is caused by accidents in. It has diverse types of larynx injuries, caused for multiple mechanisms.

OBJECTIVE

 To verify, in literature, the main causes of laryngeal complications after- orotracheal intubation and its mechanisms of injury. Revision of Literature: The searched databases had been LILACS, BIREME and SCIELO. Were updated, books and theses had been used, delimiting itself the period enters 1953 the 2009. The keywords used for the search of articles had been: complications, injuries, larynx, intubation, endotracheal, orotracheal, granulomas, stenosis. 59 references had been selected. The used criteria of inclusion for the choice of articles had been the ones that had shown to the diverse types of injuries caused for the orotracheal intubation and its pathophysiology.

FINAL CONSIDERATIONS

 This revision of literature was motivated by the comment in the practical clinic of a great number of laryngeal sequels in patients submitted to the orotracheal intubation. Of that is ahead important the knowledge, for the professionals of the area of health, the types of complications and its causes, with intention to prevent them, adopting measured of prevention of these injuries.

Endotracheal tube cuff pressure monitoring: a review of the evidence

Tracheal intubation constitutes a routine part of anaesthetic practice both in the operating theatre as well as in the care of critically ill patients. The procedure is estimated to be performed 13-20 million times annually in the United States alone. There has been a recent renewal of interest in the morbidity associated with endotracheal tube cuff overinflation, particularly regarding the rationale and requirement for endotracheal tube cuff monitoring intra-operatively.

Deep propofol sedation for vacuum-assisted bite-block immobilization in children undergoing proton radiation therapy of cranial tumors

BACKGROUND

Vacuum-assisted bite-block immobilization of the head is a reliable technique for reproducible precise head positioning as used for proton radiation in adults. We report preliminary experience using deep propofol sedation without an artificial airway in children undergoing proton radiation of cranial tumors requiring vacuum-assisted bite-block immobilization.

METHODS

Sedation was started with a bolus of i.v. midazolam followed by repeated small boluses of propofol as required to tolerate bite-block insertion and patient positioning. Sedation was maintained by continuous propofol infusion until removal of the bite block. Oxygen was administered by a nasal cannula. SpO2, endtidal CO2 taken at the nose and respiratory adverse events such as coughing, bucking, airway obstruction, regurgitation or aspiration were recorded. Data are mean+/-sd.

RESULTS

Ten children aged 2.6+/-0.8 years were treated to date. For each child, cumulative 26.7+/-1.9 radiation fractions were administered. Propofol dose administered for induction, bite-block insertion and patient positioning was 3.9+/-0.5 mg.kg(-1). Time from insertion to removal of the bite block lasted 48.3+/-6.2 min. Endtidal CO2 values were 5.6+/-0.8 kPa (43+/-7 mmHg) and SpO2 values were 98.3+/-1.9% with spontaneous breathing, supplemental oxygen and bite block inserted. No respiratory adverse events occurred during the 267 sedation procedures performed.

CONCLUSION

Deep propofol sedation without the use of an artificial airway is an interesting technique for vacuum-assisted bite-block immobilization in young children undergoing precise radiation therapy of cranial tumors. However, simultaneous individual anesthetic challenges require pediatric anesthesiologists highly experienced with the pediatric airway, clinical alertness and closed monitoring.

Tracheostomy in the critically ill: indications, timing and techniques

PURPOSE OF REVIEW

Tracheostomy is one of the most common procedures performed in the intensive care unit. Indications, risks, benefits, timing and technique of the procedure, however, remain controversial. The decision of when and how to perform a tracheostomy is often subjective, but must be individualized to the patient. The following review gives an update on recent literature related to tracheostomy in the critically ill.

RECENT FINDINGS

Surprisingly, few data are available on the current practice of tracheostomy in the intensive care unit setting. Very few trials address this issue in a prospective, randomized fashion (randomized controlled trial). Most reports include small numbers representing a heterogeneous population, describing contrary results and precluding any definite conclusions. Evidence seems to suggest that early tracheostomy, however, might be preferable in selected patients.

SUMMARY

Due to increased experience and advanced techniques, percutaneous tracheostomy has become a popular, relatively safe procedure in the intensive care unit. The question of appropriate timing, however, has not been definitely answered with a randomized controlled trial. Instead, a number of retrospective studies and a single prospective study have shed some light on this issue. Most reports favor the performance of tracheostomy within 10 days of respiratory failure.

Local control of murine subglottis development

OBJECTIVE

To determine if subglottic development is at least partially under local control and to determine which tissue layer(s) is predominantly responsible.

DESIGN

The suglottises of 12 day-3 CD1 mice were grown in whole organ culture. The 12 subglottises were divided into 3 individual groups: +++, -++, and ---. Group+++ had all tissue layers of the subglottis intact: luminal epithelium, cricoid cartilage, inner and outer perichondrium. Group-++ had all layers intact with the exception of luminal epithelium. Group--- had all layers removed (luminal epithelium, inner and outer perichondrium) resulting in cricoid cartilage-only rings. All rings were grown in basic medium without the use of growth factors or serum for 15 days. Measurements of the rings were taken before and after organ culture growth.

RESULTS

Group+++ was the only group that experienced growth. Only luminal growth was statistically significant although all rings experienced growth in both the luminal and external diameter. Group-++ did not experience any growth. Group--- lost structural integrity with collapse of the ring and did not experience growth of any dimension of the cartilage.

CONCLUSIONS

Growth of the subglottis is under local control but may have additional influences from the outside that were not investigated here. Removal of just the epithelium stunts growth of the entire ring, but preferentially the lumen more so than the external diameter. Removal of all tissue layers around the cricoid cartilage results in a structural collapse of the ring, suggesting that the cartilage in this age group is dependent on surrounding tissues for structural integrity.

Prognostic factors in laryngotracheal injury following intubation and/or tracheotomy in ICU patients

The aim of this study was to determine the incidence of laryngotracheal injuries following intubation and/or tracheotomy in intensive care unit (ICU) patients and to analyze their prognostic factors. This prospective study includes the clinical data and endoscopic exploration of 654 ICU patients who underwent oro-tracheal intubation between September 1992 and February 1999. The prognostic factors for upper airway injuries were analyzed using a multivariate statistical study. Endoscopic exploration of the upper airway 6 to 12 months after extubation revealed laryngotracheal injuries in 30 of the 280 patients examined (11%). The most important factors influencing the development of laryngotracheal lesions were the duration of the oro-tracheal intubation and the length of time in the ICU. Patients at high risk of developing injuries were those with pathological background, a non-neurological or non-surgical (medical) admission or upper-airway injuries at an early stage. The length of oro-tracheal intubation is the most important factor in the development of laryngotracheal injuries. Consequently, it is essential to establish a time limit to perform tracheotomy in ICU patients. Such timing should be adapted to each patient and pathology.

Etiology of severe pneumonia in the very elderly

The etiology of severe pneumonia requiring mechanical ventilation in the very elderly has been imprecise because of lack of comprehensive studies and low yield of diagnostic approach. Overall, 104 patients 75 yr of age and older with severe pneumonia were studied prospectively at two university-affiliated hospitals. Microbial investigation included blood culture, serology, pleural fluid, and bronchoalveolar secretions. Streptococcus pneumoniae (14%), gram-negative enteric bacilli (14%), Legionella sp. (9%), Hemophilus influenzae (7%), and Staphylococcus aureus (7%) were the predominant pathogens in community-acquired pneumonia (CAP). Staphylococcus aureus (29%), gram-negative enteric bacilli (15%), Streptococcus pneumoniae (9%), and Pseudomonas aeruginosa (4%) accounted for most isolates of nursing home-acquired pneumonia (NHAP). The case fatality rate was 55% (53% for CAP and 57% for NHAP; p > 0.5). Activity of Daily Living (ADL) Index, pulmonary, endocrine and central nervous system (CNS) comorbidities were associated with distinct microbial etiology. By multivariate analysis, hospital mortality was associated independently with 24-h urine output (odds ratio [OR], 5.6; 95% confidence interval [CI], 2.5 to 7.9; p < 0.001), septic shock (OR, 4.3; 95% CI, 1.9 to 8.9; p = 0.0059), radiographic multilobar involvement (OR, 3.7; 95% CI, 1.8 to 15.6; p = 0.02), and inadequate antimicrobial therapy (OR, 2.6; 95% CI, 1.4 to 23.9; p = 0.034). Further studies should focus on identifying effective antimicrobial regimens in randomized trials.

Apoptosis in the developing human cricoid cartilage: a pilot study

Apoptosis is widely recognized as a major phenomenon in normal development. Deficiencies in this process may lead to developmental abnormalities such as congenital subglottic stenosis. We studied apoptosis using in situ end labeling of the 3'-OH ends of fragmented DNA in 5 progressively older, normal, human cricoid cartilage specimens. Results show that apoptosis is a very active process in fetal and neonatal tissue. The process gradually slows with advancing age. In the 4- and 13-year-old specimens, minimal to no apoptosis was seen. We conclude that apoptosis plays a critical role in the intraluminal and extraluminal expansion of the cricoid cartilage.

Effects on vocal function and incidence of laryngeal disorder when using a laryngeal mask airway in comparison with an endotracheal tube

A study of 56 patients was undertaken to determine whether there is a difference in the effect of the laryngeal mask airway and the endotracheal tube on the vocal tract after short-duration anaesthesia. All the patients were interviewed pre- and post-operatively. In 43 patients, it was possible to assess the larynx using videoendoscopy and videostrobolaryngoscopy both pre- and post-operatively. Selected acoustic characteristics were investigated in 51 patients pre- and 18-24 h post-operatively. Thirty-four patients that did not have anaesthesia were used as an age-matched control. The interview showed, that patients in the LMA group complained less frequently of having post-operative laryngeal discomfort. The videostrobolaryngoscopy demonstrated minor lesions of the vocal tract in six patients in the ETT group and in one patient in the LMA group. Of the 12 voice variables evaluated, there was no significant difference in any parameter between the two groups. Both groups had a higher fundamental frequency post-operatively.

Early diagnosis and treatment of laryngeal injuries from prolonged intubation in adults

Prolonged endotracheal intubation can cause injuries to 1 or more regions of the larynx, making safe extubation impossible and leading to tracheostomy in many patients. Unfortunately, a considerable number of these patients do not benefit from early laryngeal evaluation, which may reveal potentially treatable soft, obstructive tissue before it undergoes irreversible fibrosis. Between July 1992 and December 1995, we performed immediate direct telelaryngoscopy on 142 adults who required tracheostomy because of failed extubation. When present, obstructive tissue was removed with microsurgical techniques. One hundred twenty-nine (90%) patients were decannulated within 3 weeks. The 2 main reasons for failure of early decannulation were intractable granulation (in patients with insulin-dependent diabetes) and coexisting tracheal stenosis. Immediate telelaryngoscopy is recommended in all patients who require tracheostomy because of failed extubation. Flexible laryngoscopy is not adequate for thorough assessment of laryngeal damage from prolonged intubation.

Laryngeal injuries after short- versus long-term intubation

Forty-five patients were seen over a 5-year period with laryngeal injuries following endotracheal intubation (ETI). The mean duration of ETI was 5.6 days (2 hours to 37 days). Patients intubated for less than 24 hours were most likely to present with a vocal fold immobility or an anterior glottic web. Long-term intubation was associated with the development of subglottic stenoses and granulomas. Patients with vocal fold immobility were seen more often after ETI for surgical reasons and had a significantly higher incidence of previous intubation and tobacco usage. Subglottic stenoses were seen in younger patients intubated for medical reasons and associated with nasogastric tubes and longer periods of intubation.

Endotracheal reintubation: a closer look at a preventable condition

We designed a prospective study of endotracheal intubations and reintubations in our inner city Level 1 Trauma Center, to determine the frequency and causes of reintubation and evaluate the impact of an educational intervention aimed at minimizing unplanned extubations (UEs). After an initial 3-month phase, efforts were instituted to educate healthcare providers to the causes of reintubation noted. An identical 3-month period was then studied to evaluate the efficacy of the interventions. There were 862 patients, all adults, in the initial phase of the study, with 40 reintubation events in 22 patients; of the 808 in the second phase, there were 16 reintubations in 13 patients. The reintubation rate decreased from 4.4% to 1.9% (p = 0.005). Reintubations after UEs decreased from 14% to 5.2% (rate ratio, 0.374; 95% confidence interval = 0.141, 0.990). Multiple reintubation events decreased from 45% to 18.8% (p = 0.07). Increased provider education and protocol changes were associated with lower reintubation rates.

Videolaryngoscopic Evaluation of Laryngeal Intubation Injury: Incidence and Predictive Factors

Bedside videolaryngoscopy of 73 cardiovascular surgical patients was performed before and after intubation to identify risk factors, incidence, and site of injury to the larynx. Nineteen of 44 patients with abnormal preintubation examination findings had granulation tissue present on a vocal process, compared with 3 of 20 patients who had normal findings on preintubation examination ( p < 0.05). Recent smoking history was elicited from 2 of 20 patients who had normal findings on preintubation examination and from 20 of the 44 patients who had abnormal findings on preintubation examination ( p < 0.01). Laryngeal nerve paresis was identified in 21 of 64 patients after extubation and was present in 7 patients before intubation. Videolaryngoscopy provides a high-quality permanent record of the laryngeal examination and is easily obtained in the critical care setting. Preintubation videolaryngeal evaluation may identify those at risk for more significant intubation injury.

Artificial airways: a survey of cuff management practices

OBJECTIVE

To determine current endotracheal and tracheostomy tube cuff management practices in adult and pediatric populations, and to compare current adult cuff management practice with those reported in use in 1984 and 1987.

DESIGN

Descriptive survey.

SETTING

Sixty-four acute care hospitals in the northeastern United States.

SAMPLE

Responders represented 93 critical care units: 59 adult and 34 pediatric units.

MEASUREMENTS

Subjects completed a survey questionnaire.

RESULTS

Forty-one percent reported cuffs were routinely deflated, with most (88%) reporting cuff deflation every 8 to 12 hours or daily. In the pediatric population, minimal occlusive volume was the most frequent technique (29%); whereas in the adult population, both minimal occlusive volume technique and minimal leak technique were used more frequently (36%). Most (93%) cuff pressures were measured every 8 to 12 hours or daily with a recommended maximum range of 20 to 30 mm Hg. Cuff deflation and cuff inflation were performed more often by the nursing staff (36%). Cuff pressures were performed more often by respiratory staff (71%). There were no statistically significant differences in the cuff management practices between the adult and pediatric populations. In comparing the results for adults to the data of 1984 and 1987, most cuff management practices changed from every 8 hours or less to every 8 to 12 hours or daily, and the nursing responsibility for these techniques increased (22%).

CONCLUSION

Most responders do not routinely deflate cuffs. Cuff management practices are performed less frequently, and nursing responsibility for these techniques has increased.

CT of minor intubation trauma with clinical correlations

Even when performed by an experienced physician, endotracheal intubation is more traumatic than previously supposed. Following emergency intubation, patients have little probability of having a normal larynx. One-hundred patients underwent CT scan of the larynx 6 months or more following endotracheal intubation of short duration (up to 8 h). Ten patients (Group 1) with respiratory arrest underwent emergency intubation; 90 surgical patients (Group 2) underwent anesthesia with endotracheal intubation. Indirect laryngoscopy was performed in 59 symptomatic patients. Abnormal CT findings were present in 86 out of 100 patients. CT irregularities, which included tears, scars and small laryngoceles, were noted on indirect laryngoscopy in 59 symptomatic patients. The laryngeal damage following endotracheal intubation is surprisingly high.

The airway: problems and predictions in 18,500 patients

The purpose of this study was to describe methods, risk factors, and outcomes of airway management in all patients (obstetrics excluded) attended by anaesthetists over 27 months. Preoperatively, anaesthetists recorded patient factors and assessed four airway characteristics. Methods of tracheal intubation and ease of direct laryngoscopy following general anaesthesia (easy, awkward, difficult) were noted. Factors predictive of poor outcome and the value of the preoperative airway examination were determined. For 18,205 patients following a direct laryngoscopy, (GA), tracheal intubation was difficult (> 2 laryngoscopies) in 1.8% and awkward (< or = 2 laryngoscopies) in 2.5%. This approach was a failure in 0.3%, and surgery was postponed in 0.05%. However, an alternative approach to direct laryngoscopy, (GA) was the first choice in 353 patients. Risk factors for difficult tracheal intubation included male sex, age 40-59 yr and obesity (P < or = 0.01). For direct laryngoscopy, (GA), airway characteristics predictive of difficult tracheal intubation were decreased mouth opening (relative risk 10.3), shortened thyromental distance (9.7), poor visualization of the hypopharynx (4.5), and limited neck extension (3.2), any two (7.6) and more than two (9.4) (P < 0.01). For 1,856 patients (10.0%) where at least one airway characteristic was abnormal, a direct laryngoscopy, (GA) resulted in 8.3% awkward and 6.0% difficult tracheal intubations. For patients with no abnormal airway characteristics, tracheal intubation was easy in 96.3%. Where tracheal intubation was difficult, 34.3% of patients had one or more abnormal airway characteristics preoperatively. Patients with difficult tracheal intubation had an increased rate of desaturation (< 90%), hypertension (> 200 mm Hg) and dental damage on induction of anaesthesia. It is concluded that difficult tracheal intubations occurred infrequently but were associated with increased morbidity. Patient factors and four physical airway characteristics were useful predictors but limited in identifying all problems.

Posterior glottic stenosis in children

The management of posterior glottic stenosis resulting from impaired crico-arytenoid joint (CAJ) mobility in infants and children presents a perplexing and frequently unrewarding surgical dilemma; any improvement in the airway is almost invariably at the expense of the voice. Progress in this area has been hampered not only by the rarity of cases, but also by the technical difficulty of achieving an accurate diagnosis at endoscopy. In order to address this problem we have undertaken a retrospective analysis of 35 infants and children, treated at Great Ormond Street between 1980 and 1991, with endoscopically confirmed impairment of CAJ mobility. Five cases of mild posterior glottic stenosis were successfully treated either conservatively or by laser scar division. Thirty cases of moderate or severe stenosis were identified, and 19 of these have undergone corrective surgery. Of these 19, 17 had a prior tracheostomy, and 12 have been decannulated. No problems with aspiration were encountered but five (i.e. 25%) of those treated surgically suffered a deterioration of voice quality.

Inter-arytenoid glottic bar following intubation

Inter-arytenoid glottic bar is a rare complication of prolonged endotracheal intubation. We present two such cases and their treatment. The aetiology of this complication is multifactorial and involves local factors--local trauma, movement of the endotracheal tube within the larynx, infection, and anatomical influences--together with systemic factors such as in our two cases. The relative importance of these factors is discussed. A comment is also made on the use of a pre-operative topogram and the importance of an ENT assessment in patients with airway problems following prolonged intubation.