Endotracheal Tube Obstruction Research Articles

Acoustic monitoring of the artificial airway--experimental results.

Non-invasive acoustic airway-monitoring was evaluated in an experimental study. Recording amplitude and travel time of acoustic pulse response, an acoustic pattern of airway's geometry was then calculated. Measurements on models and excised human cadaver lungs were performed to discover whether displacement or obstruction of the artificial airway could be detected by its acoustic equivalent. Regression analysis revealed a close correlation between displacement of tracheostomy tubes and the shifting of the acoustic area-distance function (corr. coeff.: 0.97-1) and an adequate correlation between acoustic and planimetrical determination of cross-sectional area within the tubes (corr. coeff.: 0.78). Dispersion analysis confirmed reasonable reliability of acoustic cross-sectional measurements (Coefficients of variation: 0.6-2.1%). The acoustic mapping thus provides an excellent approximation of the true displacement and/or obstruction of tracheostomy and endotracheal tubes. We conclude that acoustic monitoring may provide a helpful tool for achieving an early warning system of airway disturbancies in intubated and mechanically ventilated patients, as geometrical changes of airway configuration may be detected before they lead to relevant effects on respiratory metabolism.

Acute Intraoperative Endotracheal Tube Obstruction Associated with a Heat and Moisture Exchanger in an Infant

Acute Intraoperative Endotracheal Tube Obstruction Associated with a Heat and Moisture Exchanger in an Infant

Safety of Combined Heat and Moisture Exchanger Filters in Long-term Mechanical Ventilation

To evaluate the safety of a combined heat and moisture exchanger filter (HMEF) for the conditioning of inspired gas in long-term mechanical ventilation (MV). Randomized controlled trial. Medical ICU in a large teaching hospital. One hundred fifteen consecutive patients who required > or = 48 h of MV. Patients were randomized at intubation time (day 1) to receive inspired gas conditioned either by a water-bath humidifier heated at 32 degrees C (HWBH) or by an HMEF (Hygroster; DAR; Mirandola, Italy). The two study groups were comparable in terms of primary pathologic condition at the time of hospital admission, disease severity as measured by the Simplified Acute Physiology Score, and ICU mortality. They did not differ with respect to ventilator days per patient (mean +/- SD: HMEF, 7.6 +/- 6.5; HWBH, 7.8 +/- 5.8), incidence of endotracheal tube obstruction (HMEF, 0/59; HWBH, 1/56), and incidence of hypothermic episodes (HMEF, five; HWBH, two). In 41 patients receiving MV for > or = 5 days, the morphologic integrity of respiratory epithelium was evaluated on day 1 and day 5, using a cytologic examination of tracheal aspirate smears. The state of ciliated epithelium was scored on a scale from 0 (poorest integrity) to 1,200 (maximum integrity), according to a well-described method. In both patient groups, the scores slightly but significantly decreased from day 1 to day 5 (mean +/- SD: HWBH, from 787 +/- 104 to 745 +/- 88; HMEF, from 813 +/- 79 to 739 +/- 62; p < 0.01 for both groups); there were no statistically significant differences between groups. These data indicate acceptable safety of HMEFs of the type used in the present study for long-term mechanical ventilation.

Effects on Compliance and Resistance of Bolus Administration vs. Slow Infusion of Surfactant 113

Background: Bolus administration of surfactant (surf) can lead to obstruction of bronchus or endotracheal tube and has potential hazards concerning circulation and cerebral perfusion. We gave surf as a slow infusion (inf) via a small catheter within the tube and compared effects on static compliance (C) and resistance(R) with the recommended bolus administration (bol).

Bronchospasm During Pneumoperitoneum

Bronchospasm During Pneumoperitoneum

Anesthesia for Stereotactic Radiosurgery in Children

The development of stereotactic radiosurgery has been a major advance in the treatment of intracranial lesions. By using a stereotactic head frame attached to the skull, large doses of radiation can be delivered precisely to the lesion while sparing surrounding tissues. Although adults can usually undergo this procedure with local anesthesia or conscious sedation alone, children frequently require general anesthesia. This report describes our experience with the anesthetic management of all children who have received this therapy at our institution since the inception of our stereotactic radiosurgery program in 1986 through June 1993. Sixty-eight radiosurgery procedures were performed in 65 patients. Anesthesia time averaged 9.2 h (range, 7-15). Twenty-two patients (ages 11-17; mean 14.3) received local anesthesia alone, two patients (ages 11 and 15) received local anesthesia plus i.v. sedation, and 44 patients (ages 2-14; mean, 7.3) received general anesthesia. Four potentially serious anesthesia-related events occurred; in one child (age 7) receiving general anesthesia, an endotracheal tube obstruction developed during radiosurgery requiring rapid reintubation while the child was still in the head frame; another (age 7) who was undergoing chemotherapy and had neutropenia and rhinitis had a lobar collapse while intubated, requiring mechanical ventilation and endotracheal tube suctioning for lung expansion. Another (age 5) with a recent upper respiratory tract infection had copious endotracheal secretions and sinusitis (ethmoid and maxillary) noted on initial computed tomography scanning and was given antibiotics and decongestants (following nasotracheal extubation), and another (age 15) receiving sedation without endotracheal intubation vomited an undigested meal midway through the procedure while her head was partially immobilized in the head frame.(ABSTRACT TRUNCATED AT 250 WORDS)

Complicaciones de ventilación mecánica en niños

Morbidity and lethalh/ associated to nechanica x'enHation were prospec'ively recorded in 294 children who 'equired 300 consecutive artificial respiration procedures. Fourteen complications were previously defined, incljding those related to intubation, extubct'on, endotrocheal or Tacheostomy tube, venti ator failure, together with medical co7iplications. The mean age of these patients was 20 months [range ] month to 14 years). Aveage duration of ventilatory support was 6.32 days, range one hour to B5 days. One or more complications were recorded in 166 cases (55.3%), the most frequen being rigfr mainstem bronchus intubat'on i l l.6%), self extubation (11.6%), endotracheal tube obstruction ( 1 1 . 3 % ) , osocomial pneumonia (9.3%), prolonged intubation attempt (6.6%} and barotrauma (6.6%). Whole legality rate was 32.6% [96 patients), being d'rectly related to mechanical ventilation in seven cases: in two patients it was due to *ube obstruction,, in one child to oarotrcuma, in another one to massive atelectasis and Jn three infants less tha^ one year old with complex card ac congenital defects and long periods of mechanical vent'lation, to nosocomial pneumonia.

Reinforced Endotracheal Tube Obstruction

Reinforced Endotracheal Tube Obstruction

An unusual cause of intraoperative hypoxemia

Congenital anomalies of the tracheobronchial tree are rare occurrences; however, they can lead to pulmonary complications. A tracheal bronchus is an anatomic variant in which an ectopic bronchus originates directly from the tracheal wall above the carina. Presented is a case of intracperative hypoxemia due to right upper lobe collapse. Despite what appeared to be proper endotracheal tube positioning, this clinical scenario was found to be the result of endotracheal tube obstruction of a tracheal bronchus supplying the right upper lobe. Fiberoptic bronchoscopy proved to be a rapid diagnostic and therapeutic tool, as the endotracheal tube was able to be visually positioned above this aberrantly located bronchus.

Endotracheal Tube and Tracheobronchial Obstruction as Causes of Hypoventilation With High Inspiratory Pressures

Two cases of difficult ventilation are presented, the first caused by endotracheal tube obstruction with nasal turbinate, and the second caused by tracheobronchial obstruction with blood clots. The clinical presentation in each case was characterized by extreme difficulty in ventilating and severe hypercapnia despite vigorous ventilatory efforts with either a mechanical ventilator or resuscitator bag. A simple manipulation of the endotracheal tube cuff helped to differentiate between increased impedance caused by endotracheal tube obstruction as opposed to increased respiratory system impedance beyond the tip of tube. In the second patient, in whom even a short interruption of ventilation was poorly tolerated, simultaneous rigid bronchoscopy (for removal of intratracheal masses) and ventilation via endotracheal tube were successfully performed.

Acoustic method to estimate the longitudinal area profile of endotracheal tubes.

A problem in mechanical ventilation is the accumulation of mucus secretions in the endotracheal tube (ETT), which tends to reduce the patent cross-sectional area. Here we characterized the extent and locus of the ETT obstruction using an acoustic reflection method recently modified to be applied at bedside. Experiments were conducted both in vivo in 10 intubated patients and in vitro in ETT with or without known constrictions of 1 to 3 mm over 5 cm, located at various distances from the ETT entry: 5, 10, 15, and 20 cm. Acoustic results were compared with the results obtained by an hydraulic reference method, which was the only method available to measure ETT obstruction in mechanically ventilated patients. In vivo acoustic results showed that area reductions were maximal near the tracheal extremity of the ETT, with a range from 2 to 36% (mean value 13 +/- 10%), when estimated relative to the area measured in an unused ETT of the same inner diameter (7 to 9 mm). Statistical analysis of the differences between acoustic reflection data and hydraulic data showed that the two methods did not differ significantly. In vitro acoustic results obtained in constricted ETT showed a highly significant correlation with the actual area (r = 0.97, p = 0.0001). Thus, reductions in ETT area may be detected, quantified, and located by the present acoustic reflection method, which therefore provides a means to avoid emergency extubation because of ETT obstruction.

Use of the esophageal stethoscope in pediatric transports

Monitoring cardiac and respiratory function during helicopter transports can be difficult, so the authors devised a study of the esophageal stethoscope for pediatric patients. The study was conducted at Pediflite in Tennessee, which transports between 250 to 300 pediatric patients every year. A disposable esophageal stethoscope was used as an adjunct to other monitoring systems in intubated patients. Prior to transport, the stethoscope was placed orally by the respiratory therapist and advanced to the point where heart sounds are heard best, at which point breath sounds can also be heard clearly. The device's ear piece easily fit under the crew member's headphones, which block helicopter noise. Three sizes of stethoscope are available: a 6 French for patients 1 day to 4 years old, a 9 French for those 4 to 12 years old, and an 18 French for patients 12 years of age or older. The esophageal stethoscope was used in 55 patients ranging in age from newborn to 18 years. Eighteen of 55 (33%) had multiple trauma or closed head injury, and 14 of 55 (25%) suffered respiratory failure. The esophageal stethoscope proved to be easy to place, had a low risk of complications and allowed continuous access to breath sounds. In addition, the ability to hear heart tones was minimally affected by noise or vibration. Due to its ability to continuously monitor breath sounds, endotracheal tube obstruction or displacement can be rapidly detected by the esophageal stethoscope. Also, if there is failure of the cardiopulmonary monitor, heart sounds can be continuously monitored. The esophageal stethoscope is a simple but potentially valuable tool in pediatric and neonatal transports for monitoring respiratory and cardiac status.

The Australian Incident Monitoring Study. The pulse oximeter: applications and limitations--an analysis of 2000 incident reports.

The first 2000 incidents reported to the Australian Incident Monitoring Study were analysed with respect to the role of the pulse oximeter. Of these 184 (9%) were first detected by a pulse oximeter and there were a further 177 (9%) in which desaturation was recorded. Of the 1256 incidents which occurred in association with general anaesthesia 48% were "human detected" and 52% "monitor detected". The pulse oximeter was ranked first and detected 27% of these monitor detected incidents; this figure would have been over 40% if an oximeter had always been used and its more informative modulated pulse tone relied upon instead of that of the "bleep" of the ECG. The pulse oximeter is the "front-line" monitor for endobronchial intubation, the fourth most common incident in association with general anaesthesia (it detected 87% of the 76 cases in which it was in use). It also played an invaluable role as a "back-up" monitor in 40 life-threatening situations in which "front-line" monitors (e.g. oxygen analyser, low pressure alarm, capnograph) were either not in use, were being used incorrectly or failed. Other situations detected, in order of frequency of detection, were: circuit disconnection, circuit leak, desaturation (severe shunt), oesophageal intubation, aspiration and/or regurgitation, pulmonary oedema, endotracheal tube obstruction, severe hypotension, failure of oxygen delivery, hypoxic gas mixture, hypoventilation, anaphylaxis, air embolism, bronchospasm, malignant hyperthermia, and tension pneumothorax.(ABSTRACT TRUNCATED AT 250 WORDS)

An unusual case of endotracheal tube cuff dysfunction

We report an unusual case of endotracheal tube obstruction secondary to alteration of the preoperative fasting period. A patient scheduled for coronary artery bypass grafting had been instructed to take nothing by mouth except scheduled medication with sips of water prior to surgery. Induction of anesthesia and tracheal intubation were accomplished without incident. However, ventilation was impaired by a nonfunctional endotracheal tube cuff. Various maneuvers ( e.g., inflation and deflation of the cuff and advancement of the tube) were attempted without success. When the tube was removed, we found an adherent mass of chewing gum. The patient's trachea was reintubated, and surgery proceeded uneventfully. We believe that the mass of gum caused enough deviation of the endotracheal tube to impair ventilation. The safety of preoperative gum chewing and liquid ingestion is discussed. Other incidents of anesthetic problems caused by modification of the traditional preoperative fast are highlighted.

Une cause rare d'obstruction de la sonde d'intubation

A case is reported of endotracheal tube obstruction due to impaction of a turbinate. This complication occurred during a first attempt of nasotracheal intubation in an ASA 1 18-year-old patient. Once the tube had been inserted into the trachea, manual ventilation was impossible. The diagnosis was made on removal of the completely obstructed tube. Differential diagnosis was sudden severe bronchospasm or a herniated cuff. Anaesthesiologists should be aware of this rare complication when carrying out nasotracheal intubation. Means of prevention are proposed.

A Single-blind Study of Combined Pulse Oximetry and Capnography in Children

This single-blind study examined four levels of monitoring in 402 pediatric cases. Patients were randomly assigned to one of four groups: 1) oximeter and capnograph; 2) only oximeter; 3) only capnograph; or 4) neither oximeter nor capnograph data available to the anesthesia team. An anesthesiologist, not involved in patient care, observed all cases and continuously recorded hemoglobin oxygen saturation (Spo2), ECG, expired CO2, and the oximeter plethysmographic output. Mean age, weight, ASA physical status, airway management (mask or endotracheal tube), and anesthetic technique were similar in each group. Two-hundred sixty problems were documented in 153 patients. Fifty-nine events in 43 patients resulted in "major" desaturation (Spo2 less than or equal to 85% for greater than or equal to 30 s). Fifteen "major" capnograph events (esophageal intubation, disconnection, accidental extubation, or obstructed endotracheal tube) were observed in 11 patients; 8 of these also developed varying degrees of desaturation. One-hundred thirty "minor" desaturation events (Spo2 less than or equal to 95% for greater than 60 s) and 79 "minor" desaturation events (hypercarbaria or hypocarbia) were observed. A number of problems fulfilled criteria in multiple categories. Infants less than or equal to 6 months of age had the highest incidence of major desaturation events (18 of 65 [27%]) compared to toddlers 7-24 months of age or children greater than 24 months of age (P less than 0.001). Blinding the oximeter data increased the number of patients (12 vs. 31) experiencing major desaturation events (P = 0.003); blinding the capnograph data altered neither the frequency of desaturation events nor the incidence of major capnograph events.(ABSTRACT TRUNCATED AT 250 WORDS)

Unusual Cause of Endotracheal Tube Obstruction

Unusual Cause of Endotracheal Tube Obstruction

Endotracheal Tube Obstruction in a Patient with Status Asthmaticus

Endotracheal Tube Obstruction in a Patient with Status Asthmaticus

Endotracheal Tube Obstruction: Recognition and Management

Endotracheal Tube Obstruction: Recognition and Management

Endotracheal Tube Obstruction due to Mucous Crust after General Anesthesia

Endotracheal Tube Obstruction due to Mucous Crust after General Anesthesia