Liquid Aspiration Research Articles

Responding to the Dysphagia Consult: A Report-Writing Primer

Responding to the Dysphagia Consult: A Report-Writing Primer

Endotracheal intubation in horses: a study of two cuff inflation pressures, correlation with liquid aspiration, and tracheal wall damage

Nine adult horses were anesthetized for a nonsurvival abdominal adhesion study. Horses were randomly assigned into two groups to receive endotracheal tube cuff pressures of either 80 cm H2O (Group P80) or 120 cm H2O (Group P120). After intubation (Bivona 30 mm ID), anesthesia was maintained with isoflurane. Horses were ventilated 10 times per minute with a suitable inspiratory pressure to maintain Pe’CO2 in the 35-40 mm Hg (4.7-6.0 kPa) range. Cuff pressure was continuously monitored with a pressure transducer (TruWave, Baxter) calibrated to the atmospheric pressure and maintained at a constant pressure. Twenty-five millilitres of methylene blue dye in saline were instilled proximal to the cuff over 5 minutes. The horses were euthanized 123 ± 23 minutes later (mean ± SD). Immediately, the trachea was opened distal to the tip of the endotracheal tube, and the mucosa was observed for evidence of dye leaking past the cuff. The cervical trachea was resected and the lumen exposed by a ventral longitudinal incision. Biopsies (1-2 rings) were obtained at mid-cuff level and distal to the tip of the endotracheal tube, and placed in formalin for later histologic examinations (H&E stain).

Professor Nicolas Taptas (1871-1955): a pioneer of post-laryngectomy voice rehabilitation.

To report on the career of Professor Nicolas Taptas of Constantinople (1871-1955) and his contribution to the development of an artificial larynx. Historical review. The unpublished documents of Taptas's family archives and one of his papers, describing his own original technique for voice rehabilitation after total laryngectomies, were studied. In his texts, Taptas described the application of external laryngeal prostheses in one of his patients who underwent total laryngectomy. Taptas meticulously recorded his own first successful attempt in a woman with cancer of the larynx. He was one of the first scientists who, at the end of the 19th century, devised an external laryngeal prosthesis, which had the advantage of rehabilitating a sufficiently strong whispering voice; by using a prototype valve, he avoided problems of aspiration of liquids and food to the bronchi. Nicolas Taptas's contribution to the development of the artificial larynx was vital because he devised and applied one of the first external laryngeal artificial prostheses with satisfactory functional results.

Dysphagia severity scale

A simple, broadly applicable, standardized dysphagia severity scale would be useful to standardize dysphagia evaluations, to monitor recovery and efficacy of treatment and to study the consequences of dysphagia. We developed a global Dysphagia Severity Scale (DSS) from videofluorographic swallowing studies which included subjective clinical ratings of functional swallowing. We rated laryngeal penetration/aspiration (P/A) and pharyngeal retention (PR), and then assessed methods for scoring severity of P/A and PR and for combining them in a global scale. Each method was tested by correlation with overall clinical severity ratings. The highest correlations were found by: 1) scoring P/A based on which foods were aspirated (no aspiration or penetration; penetration only; thin liquid aspiration; thick liquid, pudding, or chewed solid food aspiration; 2) scoring PR based on how much food was retained (none; minimal; moderate; severe); and 3) combining P/A and PR by taking the higher of the two scores as the final DSS rating. The final global DSS score and the clinical severity rating correlated well (r = 0.71). This proposed scale shows promise for rating global dysphagia severity.

Clinical, endoscopical and manometric evaluation of swallowing in patients with acquired autoimmune myasthenia gravis

Dysphagia, or difficulty swallowing, is a common problem following myasthenia gravis (MG) and may lead to aspiration of saliva, food or liquids. We herein present 22 MG patients, with complaint of dysphagia, evaluated by phonoaudiological evaluation, nasofibrolaryngoscopical analysis and manometry of upper esophageal sphincter. The main objective was to evaluate the phases of the swallowing process and anatomical and functional aspects of oropharyngeal musculature. The age of patients varied from 19 to 74 years; being 19 female and 3 male. The main data were: (1) statistically significant relation between the phonoaudiological clinical evaluation and nasofibrolaryngoscopical one; (2) stomatognatical system disorders present in 100%; (3) swallowing and chewing disorders present in 100%, when clinically evaluated, and in 81,8% when evaluated by the nasofibrolaryngoscopy; (4) statistically significant relation between penetration/aspiration and antecedents of pneumonia; (5) stomatognatical muscles very altered, difficulty controlling the bolus, collection of food in the pharynx or larynx and presence of penetration and/or aspiration showed significant correlation with weakness of a pharyngeal muscles. These findings justify the necessity to evaluate clinically the swallowing phases in MG patients, with the main purpose to prevent both aspiration and dehidration from inadequate oral intake.

Maturation and transformation of reflexes that protect the laryngeal airway from liquid aspiration from fetal to adult life

Several reflexes are initiated in the fetus and newborn when hypochloremic or strongly acidic solutions contact the epithelium that surrounds the entrance to the laryngeal airway. These reflexes, known collectively as the laryngeal chemoreflex (LCR), include startle, rapid swallowing, apnea, laryngeal constriction, hypertension, and bradycardia. Many studies have shown that prolonged apnea associated with the LCR may be life threatening and might conceivably be a cause of sudden infant death syndrome. This certainly may be true, but the concept of a lethal LCR paradoxically contrasts with the view that these several reflexes have an important airway-protective role. As the infant matures, rapid swallowing and apnea become much less pronounced, whereas cough and possibly laryngeal constriction become more prominent. This transformation is primarily related to central neural processing rather than to changes in the airway mucosal “water receptors” that initiate the reflex. The LCR develops in the fetus, in an all-aqueous environment, during a period in which aspiration of amniotic fluid poses a serious threat to life. This and other considerations suggest that the transformation in LCR responses from fetal to adult life can be viewed as functionally appropriate to their primary role in defending the airway from aspiration. The laryngeal “water receptors” that initiate the LCR in infants and adults alike appear to be the primary sensory mechanism for defending the airway from aspiration of liquids.

Chronic Aspiration Without Gastroesophageal Reflux as a Cause of Chronic Respiratory Symptoms in Neurologically Normal Infants

To describe 13 neurologically normal infants with chronic respiratory symptoms who had swallowing dysfunction with silent chronic aspiration without gastroesophageal reflux (GER) as the cause of their respiratory symptoms. Infants with neurologic disorders and infants with GER are known to have chronic respiratory symptoms. Isolated swallowing dysfunction and aspiration without GER in neurologically normal infants have not been widely reported. Retrospective chart review. A tertiary pulmonary-care center at a children's hospital. One hundred twelve otherwise healthy infants referred for respiratory symptoms who underwent esophageal pH studies and videofluoroscopic swallow studies (VSSs). The records of infants referred between January 1997 and December 1999 to the Department of Pediatric Pulmonology who underwent 24-h esophageal pH monitoring and VSS as part of an evaluation for recurrent stridor and/or wheezing were reviewed. Significant GER was diagnosed if the percentage of time with esophageal pH < 4 was > 6%. Infants included in the study presented with recurrent respiratory symptoms, were born at term, were neurologically normal, had normal results of esophageal pH studies, but had abnormal results of VSSs (n = 13). All 13 infants presented with a variety of recurrent respiratory symptoms including wheezing and intermittent stridor. Ten of 13 infants had spitting and/or choking episodes with feeding. The mean (+/- SD) age at the onset of symptoms was 2.0 +/- 1.6 months, and the mean age at VSS was 5.9 +/- 3.4 months. All 13 infants had normal results of 24-h esophageal pH studies but had abnormal results for VSSs. All infants had evidence of swallowing dysfunction and direct silent aspiration of liquids with thin consistency. Six infants also were aspirating liquids with thick and/or semi-thick consistencies. None of the infants had evidence of structural anomalies on esophagograms. Nine infants were treated with thickened food, and in four infants oral feedings were stopped. Three of these infants required nasojejunal feeding, and one infant required gastrostomy tube feeding. VSSs were repeated every 3 months. In all infants, swallowing dysfunction resolved within 3 to 9 months. All infants tolerated the resumption of oral feeding. Videofluoroscopic documentation of the resolution of aspiration was followed by the resolution of respiratory symptoms in all infants. There is a subgroup of otherwise healthy infants, presenting with wheeze and/or stridor, who have isolated swallowing dysfunction and silent aspiration as the cause of their respiratory symptoms.

Respiratory complications related to bulbar dysfunction in motor neuron disease

Bulbar dysfunction resulting from corticobulbar pathway or brainstem neuron degeneration is one of the most important clinical problems encountered in motor neuron disease (MND) and contributes to various respiratory complications which are major causes of morbidity and mortality. Chronic malnutrition as a consequence of bulbar muscle weakness may have a considerable bearing on respiratory muscle function and survival. Abnormalities of the control and strength of the laryngeal and pharyngeal muscles may cause upper airway obstruction increasing resistance to airflow. Bulbar muscle weakness prevents adequate peak cough flows to clear airway debris. Dysphagia can lead to aspiration of microorganisms, food and liquids and hence pneumonia. MND patients with bulbar involvement commonly display an abnormal respiratory pattern during swallow characterized by inspiration after swallow, prolonged swallow apnoea and multiple swallows per bolus. Volitional respiratory function tests such as forced vital capacity can be inaccurate in patients with bulbofacial weakness and/or impaired volitional respiratory control. Bulbar muscle weakness with abundant secretions may increase the risk of aspiration and make successful non-invasive assisted ventilation more difficult. We conclude that an evaluation of bulbar dysfunction is an essential element in the assessment of respiratory dysfunction in MND.

Aspiration and Dispensing of Biological Liquids in the Micro- and Submicroliter Range with High Precision

This paper describes the design and the fabrication as well as the measurement results of a new micropipetting device designed for the pipetting of biological liquids in the micro- and submicroliter range. The device is a modular set-up including a precision pipetting head with two integrated sensors realized in silicon bulk micromachining and a coupled piezo disk-type actuator to fulfil the force and stroke requirements for fast pipetting. With this device we have pipetted water from 0.4 to 2.7 μl and serum from 0.45 μl to 3.1 μl. The measurements were undertaken in open-loop mode and the coefficients of variation for repeated pipetting cycles were below 4%. Due to the integrated sensors the system can be expanded to a closed-loop system to compensate for the piezoactuator's hysteresis and drift, thus further increasing precision and accuracy.

Comparison of characteristics and limits of detection of pneumatic micronebulizers and a conventional nebulizer operating at low uptake rates in ICP-AES

Three micronebulizers, the high-efficiency nebulizer (HEN), the microconcentric nebulizer (MCN) and the micromist (MM), were compared with a conventional pneumatic concentric nebulizer working at low liquid flow rates in ICP-AES. The gas back-pressure, the free liquid aspiration rate, the drop size distribution of primary and tertiary aerosols, the solvent and analyte transport rates, the emission intensity and the limits of detection were measured. The solvent evaporation inside the spray chamber proved to be a very important transport phenomenon when working at very low liquid flow rates. The micronebulizers produced finer primary aerosols, higher solution transport rates through the spray chamber and higher sensitivities than the conventional pneumatic concentric nebulizer. The HEN used in this work provided slightly lower ICP-AES limits of detection than the other two micronebulizers, but at the expense of a higher back-pressure.

The chewable barium tablet slow tracking of oral and pharyngeal swallowing dysfunction.

Dysphagia can be due to oral or pharyngeal dysfunction as well as to esophageal causes. Oral and pharyngeal disturbances, however, are more common in older people because of their attendant risks of laryngeal, tracheal, and pulmonary aspiration. To guide any dietary prescriptions it is important to establish whether the patient can best tolerate liquids, soft foods, solid chewable boluses, all, or none of these. It therefore becomes important to supplement liquid barium swallowing studies with soft and chewable boluses mixed with barium. Here I describe the novel introduction of chewable barium tablets in conjunction with routine swallowing studies. Chewable barium tablets, if used properly, are safe, supply needed information, and can shorten the evaluation of oral and pharyngeal dysfunction studies. Because of the granular appearance of the tablets, aspiration due to this solid chewable bolus can be distinguished from liquid aspiration. Moreover, if the barium tablets are swallowed whole, they can help delineate esophageal strictures if the oral and pharyngeal phases of swallowing are normal.

Aspiration on modified barium swallow (MBS): Relationship of examination materials and clinical implications

Risk of aspiration is often an indication for performance of a MBS. Multiple examining materials of variable viscosity are used and silent aspiration that does not elicit a cough reflex may be observed. Dietary recommendations are based on these findings to permit safe swallowing in patients at risk for aspiration, We evaluated a total of 109 patients (46W; 63 M; mean age, 67 yrs) who showed aspiration on MBS to determine which materials were most often responsible, the prevalence and nature of aspiration, and the clinical implications of these observations. The materials used were low and high viscosity barium suspensions, barium paste and a paste-coated cookie. Aspiration with liquid barium only was seen in 95 (87%) of the 109 patients; liquid and paste aspiration were both present in 7 (6%) patients, and 7 others had a mixture of aspiration events. Only 2 patients each had only paste or solid aspiration. Aspiration induced a cough in 80 (73%) patients but was silent in 29 (27%). Conclusions: 1) Liquids are the main concern for patients at risk of aspiration; 2) Silent aspiration of liquids is not uncommon; 3) MBS is an important examination in determining the • aspiration risks and in identifying silent aspirators; and 4) Patients on liquid diets who have not had a swallowing evaluation and may be silent aspirators are at greatest danger for aspiration-related complications.

Burns in children younger than two years of age: an experience with 200 consecutive admissions.

Children <2 years of age are at increased risk of sustaining burn injury and are considered more difficult to manage than older children. We performed this data collection to facilitate better understanding of the clinical characteristics of this unique subpopulation of injured children. We collected data on 200 consecutive children <24 months of age who required admission to a regional pediatric facility between September 1, 1991 and August 22, 1993 for management of acute burns. The Shriners Burns Institute is a 30-bed regional facility that is verified as a pediatric burn center by the American College of Surgeons and American Burn Association Burn Center verification process. It provides comprehensive acute and long-term free care to children with burn injuries. We have a very busy outpatient clinic and commonly manage small burns in the outpatient setting; however, children managed as outpatients were not included in this review. Criteria for outpatient management include: 1) a burn that is <15% of the body surface so that fluid resuscitation is not required, 2) the ability to take fluids by mouth (excludes children with significant perioral burns), 3) no suggestion of possible airway involvement (no suggestion of hot liquid aspiration), 4) reliable family with transportation resources that will allow for clinic visits, and 5) no question of abuse. Children were managed uniformly, emphasizing prompt wound excision and closure.1 Children with small (<10% of the body surface) scald burns were treated with topical therapy with dressing changes generally once daily. When, after 3 to 7 days of such therapy, a full-thickness component was clearly evident on physical examination, they underwent surgery for excision and autografting of this component. Clean superficial wounds were generally covered with porcine xenograft …

Functional utility and oncologic safety of near-total laryngectomy with tracheopharyngeal speech shunt in a Third World oncologic center

This prospective study analyzes the feasibility, oncologic safety and functional utility of Pearson's near-total laryngectomy with tracheopharyngeal shunt (NTL-TPSS). The procedure was found to give gratifying locoregional control in 30 consecutive advanced T3 and selected T4 tumors involving the larynx (n = 11) and hypopharynx (n = 19) and managed at Kidwai Memorial Institute of Oncology, Bangalore, India. The oncologic "safety" of this technique was established in following examinations, ranging from 18 to 44 months (median, 22.2 months). A locoregional control rate of 74% was obtained. Lung-powered "shunt" speech was acquired with ease in periods ranging from 7 days in speakers deemed "excellent" (15/29) to 20 days in those deemed "satisfactory" (8/29). Except for a single case experiencing temporary aspiration of liquids, patients did not have any swallowing difficulties following removal of nasogastric tubes. The period of hospitalization averaged 22.6 days. The complication rate was 33%, with one patient death (3.3%) occurring. The dynamics of the TPSS were analyzed in selected "speakers" and "non-speakers", using transcutaneous needle electromyography. Analysis of data supports the possibility of dynamic speech modulation. However, the favored anatomic location and design renders the shunts aspiration-proof rather than demonstrating any active sphincteric action.

Pneumonia associated with aspiration following stroke.

To determine the association between demonstrated aspiration and pneumonia in stroke patients. Chart review of 441 consecutive stroke patients admitted to a stroke rehabilitation unit within 4 months of their stroke over an 8-year period. Videofluoroscopic modified barium swallow (VMBS) was performed on all patients suspected of aspirating. In all patients, the presence or absence of pneumonia was noted. Eighty-four of the 441 (19.0%) stroke patients transferred for rehabilitation demonstrated aspiration of thin liquids on VMBS. Twelve of the 441 (2.7%) developed pneumonia while in hospital, either in the acute or rehabilitation phases. The incidence of pneumonia among proven aspirators on VMBS was 10 of 84 (11.9%) patients. Two of the 357 (0.6%) patients who were presumed nonaspirators developed pneumonia. Brain stem and right hemispheric stroke patients had a higher incidence of pneumonia. Pneumonia is an uncommon complication of stroke. However, approximately 12% of stroke rehabilitation patients diagnosed as aspirators on VMBS developed pneumonia, a 20-fold increase over presumed nonaspirators. VMBS is a potentially valuable tool in determining those patients at risk of aspiration pneumonia.

Prandial aspiration and pneumonia in an elderly population followed over 3 years

The purpose of our study was to prospectively determine pneumonia frequency and correlate it with prandial liquid aspiration and feeding status in frail elderly nursing home residents. Initially, 152 patients had video swallowing examinations (81 oropharyngeal dysphagia, 19 thoracic dysphagia, 52 without dysphagia). Those diagnosed with oropharyngeal impairment were subsequently managed with swallowing therapy or artificial feeding modalities. Patients were followed for 3 years (unless they expired earlier) and clinical courses were categorized according to the degree of prandial aspiration and feeding (PAF) status. Subjects with new lung infiltrates persisting for at least 5 days with appropriate clinical findings were diagnosed as having pneumonia and were classified according to the PAF status months in which these findings occurred. Fifty-six pneumonias were diagnosed during 4,280 months with the following frequencies: no aspiration months 0.6%; minor aspiration months 0.9%; major aspiration/oral feeding months 1.3%; major aspiration/artificial feeding months 4.4%, p < 0.001. Our results indicate that there is not a simple and obvious relation between prandial liquid aspiration and pneumonia. Artificial feeding does not seem to be a satisfactory solution for preventing pneumonia in elderly prandial aspirators.

Recognition and Management of Hot Liquid Aspiration in Children

Although infrequently reported, aspiration of hot liquid can occur in conjunction with upper-body scald burns, leading to acute compromise of the small pediatric airway with clinical features similar to those of acute infectious epiglottitis. This can be a very difficult problem if subtle signs of impending airway compromise are not appreciated. Reported here are four such cases managed over a 3-year period at a regional pediatric burn center, emphasizing points of history and physical examination that facilitate early recognition of this life-threatening problem. Aspiration of hot liquid should be suspected in children with burns in or around the mouth, particularly if there are any subtle signs of upper airway edema. If this complication is suspected, immediate endotracheal intubation should be performed in those with acute respiratory embarrassment, and prompt investigation by direct laryngoscopy in the operating room is appropriate in those who have not yet developed overt respiratory distress. [Sheridan RL: Recognition and management of hot liquid aspiration in children. Ann Emerg Med January 1996;27:89-91.]

Imaging of Tracheobronchial Injuries

Tracheobronchial injuries are rare and can be life threatening. They can result from external injuries due to blunt or penetrating trauma or from internal injuries subsequent to inhalation of fumes, gases, and aspiration of liquids or foreign bodies. The most dangerous aspect of tracheal trauma is the fact that it is easily overlooked initially. Imaging studies play a pivotal role in timely diagnosis.

Non-CO2 gaseous emissions from upstream oil and gas operations in Nigeria

The Nigerian crude oil is formed in association with natural gas. The associated gas has mostly been flared in the process of crude oil exploitation. Current estimates are that approximately 70% of produced natural gas is flared. Carbon monoxide, volatile organic compounds and nitrogen oxides emissions from oil and gas exploitation activities are presented for major combustion activities: gas flares and power generation at oil fields for oil and gas gathering systems. The emissions rates and combustion efficiency for a newly tested modified flaring system with enhanced air supply and liquid aspiration system for the atomization of the condensate phases of the flared gas was found to be capable of improving combustion efficiency by 20% or more in comparison with the conventional flare-type currently in vogue. Flare emissions for CO and NOx are an order of magnitude higher than other sources in the oil and gas sector.

Acute effects of sucralfate aspiration: Clinical and laboratory observations

Study Objective: To assess the complications associated with the aspiration of sucralfate. Design: Clinical (case report) and bench observations. Setting: Inpatient intensive care unit and experimental animal laboratory. Subjects: The case of a critically ill patient who aspirated sucralfate is presented. Fifteen Sprague-Dawley rats served as experimental animals to investigate the acute histologic effects of large-volume aspiration of sucralfate. Interventions: The patient underwent emergent intubation to relieve acute upper airway obstruction. All the animals were anesthetized and had tracheostomies performed. The experimental groups had acidic intratracheal injections of 2 ml/kg of a nonparticulate liquid (pH, 2.3; n = 6) or a sucralfate aspirate (1 ml/kg of a 5% sucralfate suspension of pH 3.6, followed by 1 ml/kg 0.1 of normal hydrochloric acid of pH 1.0; n = 4). Four hours after simulated aspiration, the rats were sacrificed and their lungs removed for histologic examination by light microscopy. Measurements and Main Results: Differences were noted in histopathologic injury in the experimental groups compared to the control group using a numeric scoring scale. Nonparticulate acidic liquid aspiration caused a significant increase ( p < 0.05) in inflammation. Sucralfate caused a significant increase ( p < 0.05) in lung hemorrhage. A nonsignificant trend was seen with simulated sucralfate aspiration for edema and inflammation. No long-term sequelae were attributed to the clinical aspiration episode. Conclusions: Acute complications associated with aspiration of sucralfate have been identified. In the laboratory setting, simulated aspiration of sucralfate led to acute lung injury.