Use Of Tracheal Tube Research Articles

Use of a Tracheal Tube as a Nasally Inserted Supraglottic Airway in a Case of Near-Fatal Airway Obstruction Caused by Epiglottitis

Airway management is critical during near-fatal obstruction of the upper airway in epiglottitis; however, this is challenging because of the sitting posture and agitated mental status of the patient. Moreover, there is currently no established protocol for safe airway management in patients with epiglottitis. Here, we describe the use of a conventional tracheal tube as a nasolaryngeal airway to maintain airway patency at the site of airway narrowing in the supine position, which enabled alleviation of imminent airway obstruction in a patient with epiglottitis. For definitive airway establishment, tracheostomy was then safely performed in the supine position.

Strategies to prevent ventilation-associated pneumonia

Ventilation-associated pneumonia (VAP) is the commonest nosocomial infection in intensive care. Implementation of a VAP prevention care bundle is a proven method to reduce its incidence. The UK care bundle recommends maintenance of the tracheal tube cuff pressure at 20 to 30 cmH₂O with 4-hourly pressure checks and use of tracheal tubes with subglottic aspiration ports in patients admitted for more than 72 h. To evaluate the effects of tracheal tube type and cuff pressure monitoring technique on leakage of subglottic secretions past the tracheal tube cuff. Bench-top study. Laboratory. A model adult trachea with simulated subglottic secretions was intubated with a tracheal tube with the cuff inflated to 25 cmH₂O. Experiments were conducted using a Portex Profile Soft Seal tracheal tube with three cuff pressure monitoring strategies and using a Portex SACETT tracheal tube with intermittent cuff pressure checks. Rate of simulated secretion leakage past the tracheal tube cuff. Mean ± SD leakage of fluid past the Profile Soft Seal tracheal tube cuff was 2.25 ± 1.49 ml min⁻¹ with no monitoring of cuff pressure, 2.98 ± 1.63 ml min⁻¹ with intermittent cuff pressure monitoring and 3.83 ± 2.17 ml min⁻¹ with continuous cuff pressure monitoring (P <0.001). Using a SACETT tracheal tube with a subglottic aspiration port and aspirating the simulated secretions prior to intermittent cuff pressure checks reduced the leakage rate to 0.50 ± 0.48 ml min⁻¹ (P <0.001). Subglottic secretions leaked past the tracheal tube cuff with all tube types and cuff pressure monitoring strategies in this model. Significantly higher rates were observed with continuous cuff pressure monitoring and significantly lower rates were observed when using a tracheal tube with a subglottic aspiration port. Further evaluation of medical device performance is needed in order to design more effective VAP prevention strategies.

Quest for an Ideal Intubating Device

Quest for an Ideal Intubating Device

Estudo epidemiológico das infecções neonatais no Hospital Universitário de Londrina, Estado do Paraná

The greater susceptibility of neonates to infections results in higher rates of nosocomial infection (NIs) than in other patient populations. The objective of this work was to determine the frequency and profile of NIs in neonates associated to the main risk and death factors. A retrospective epidemiological study was conducted on neonates with NIs admitted to the neonatal sector at the University Hospital of Londrina, between 2001 and 2005. The mean annual rate of neonatal NI was 18.3% over the course of five years. The most frequent infections were pneumonia (46.0%) and sepsis (49.1%), which were related to a hospitalization period of over 60 days. The use of tracheal tubes and vascular catheters increased threefold the risk of sepsis. The tracheal tubes and vascular catheters increased the risk of death by 3.26 and 2.50 times, respectively. NIs contributed to 85.7% of deaths. The mortality coefficient was 15.8%.

The use of cuffed tracheal tubes for paediatric tracheal intubation, a survey of specialist practice in the United Kingdom

For more than 50 yr, uncuffed tracheal tubes have been the gold standard for intubation in children under the age of 8 yr. However, recently there has been interest in the use of cuffed tubes in paediatric practice. This survey aimed to benchmark UK practice with regard to tracheal intubation within specialist paediatric centres, exploring current cuffed tracheal tube use in children. A questionnaire was e-mailed to the paediatric intensive care unit and anaesthetic department clinical leads in all UK specialist paediatric hospitals with a paediatric intensive care unit (n = 30). Information was requested on the use of tracheal tubes across all paediatric age groups, as well as the reasons for non-use and the incidence of complications attributed to cuffed tubes. A total of 20 paediatric intensive care unit and 15 anaesthetic questionnaires were returned, equating to a response rate of 67% and 50%, respectively. Only 5% of the paediatric intensive care unit and 7% of the anaesthetic respondents routinely use a cuffed tube in children under the age of 8 yr. The commonest reason cited in both groups for non-cuff use was that there is minimal benefit to be gained over using an uncuffed tracheal tube. The most frequent specific indication for use of a cuffed tube was a reduced lung compliance (60% respondents both groups). In all, 45% of the paediatric intensive care unit respondents and 100% of the anaesthetists reported that they did not routinely monitor the intracuff pressure when using a cuffed tube. The incidence of observed complications attributed to the use of cuffed tubes was far higher amongst paediatric intensive care unit consultants (65% vs. 7% anaesthetists); however, the majority in both groups stated that such complications were no more common than when using an uncuffed tube (60% paediatric intensive care unit and 53% anaesthetists). Cuffed tracheal tubes are rarely routinely used in children, particularly in the under 8 yr age group, in specialist paediatric centres in the UK. When used, it is predominantly for a specific indication, and the monitoring of intracuff pressure is not routine. Current expert consensus is that complications are equally as common when using a cuffed as an uncuffed tube.

Introducing the ProSeal™ laryngeal mask airway need not prevent training in tracheal intubation

The LMA ProSeal® laryngeal mask airway (PLMA, Intavent Orthofix, Maidenhead, UK) was introduced into UK practice in 2001. The design features are expected to improve efficacy of ventilation, separate the respiratory and gastro-intestinal tracts and allow diagnosis of misplacement of the device [1]. We have examined the effect of the introduction of the PLMA into practice in a district general hospital on anaesthetic airway management. The PLMA was introduced to our hospital in January 2002. We interrogated our theatre database (Operating Room Scheduling and Office System (ORSOS, Per-se Technologies Inc., GA, USA) to determine the method of airway management for all general anaesthesia cases between 2002 and 2006. Cases managed by facemask were excluded. Approximately 12–14 000 general anaesthesia cases were undertaken each year. PLMA use increased from 0.4% (48/12 713) in 2002 to 11.1% (1598/14 299) in 2006. The use of a tracheal tube remained relatively constant, changing from 32.6% (4148/12 713) in 2002 to 31.0% (4428/14 299) in 2006. Use of the LMA Classic® laryngeal mask airway (cLMA, Intavent Orthofix) declined from 60.4% (7685/12 713) to 55.6% (7949/14 299) (Fig. 1). In the emergency theatre, approximately 1800 general anaesthesia cases were performed annually. Tracheal intubation varied between 68% and 72% between 2002 and 2006 with no obvious trend: the number of intubations exceeded 1200 each year. The use of the PLMA rose from 0.3% to 5.2% and use of the cLMA fell from 29% to 26% (Fig. 2). Percentage of all general anaesthesia cases each year managed with the LMA Classic, the LMA Proseal, or a tracheal tube. Percentage of emergency general anaesthesia cases each year managed with the LMA Classic, LMA Proseal, or a tracheal tube. The introduction of the cLMA was previously reported as causing a decline in the number of tracheal intubations performed, particularly during ‘daytime’ hours, with potential effects on anaesthetic training [2]. In this hospital, the introduction of the PLMA has not exacerbated this decline: over 5 years the number of tracheal intubations has shown little change. Of note, more than 4400 intubations take place in the hospital per year: (potentially ∼ 200 intubations per trainee). However, use of the cLMA has declined. We conclude that the PLMA is usually being used in preference to the cLMA for selected patients, most likely where some protection against regurgitation or higher airway seal pressures are considered to be indicated. In the emergency theatre, use of both cLMA and tracheal tube has fallen slightly. Although this might slightly reduce the number of tracheal intubations available to trainees, it is unlikely to reduce the number of ‘rapid sequence inductions’, as these cases would not be suitable for management with the PLMA. We interpret our data as suggesting the PLMA is generally being used as a refinement of the cLMA, rather than as a substitute for the tracheal tube. The use of the PLMA offers clear advantages over the cLMA in certain situations. The PLMA has added another ‘string to the bow’ of anaesthetists' airway management skills. The widespread availability of the device and its regular use has ensured trainees and consultants are both confident and competent in its use. Use of the PLMA is one of the recommendations in the Difficult Airway Society guidelines for management of failed intubation at rapid sequence induction [3]; during the 5 years that the PLMA has been available in our hospital it has been used for both airway rescue and in several difficult airway settings [4–10]. Most trainees leave here enthusiastic about its utility. It is likely that our hospital is not typical of many hospitals as our PLMA usage is higher than most. Despite this, our data suggest that widespread introduction of the PLMA, while increasing the spectrum of airway management possibilities, need not impact on opportunities for training in tracheal intubation. Dr Cook has been paid by Intavent Orthofix and the LMA Company, both of which manufacture laryngeal masks, for lecturing. Neither company had any involvement in this letter.

Airway accidents in an intensive care unit

Aim: To document the incidence of airway accidents in the Intensive Care Unit, and to identify the difference in accident rates between short term and long term intubated patients, and between endotracheal intubation and tracheostomy. Design: Prospective, observational non-interventional study. Patients and Methods: All adult patients with either an endotracheal tube or tracheostomy were divided into two groups: intubation for 24 hours, {Long-term intubation/ LTI}. The number of tube days (TDs) were calculated from the day of intubation till the day of extubation, discharge or death. The following airway accidents were noted: blocked tube (BT), unplanned extubations (UE), endobronchial intubation (EBI), kinked tube and leaking cuff. Results: 781 patients (1440 tube days) were studied. 665 patients (951 tube days) required an endotracheal tube. 116 patients (489 tube days) had a tracheostomy. 697 patients (697 tube days) required STI while 84 patients (743 tube days) required LTI. Overall there were 55 airway accidents with an incidence of 7.04% of patients and 3.82 / 100 tube days. The airway accident rate was 4.02 / 100 TD’s and 3.63/ 100 TD’s for STI and LTI, respectively, and 4.21 / 100 TD’s and 3.07 /100 TD’s for endotracheal intuibation and tracheostomy, respectively. Blocked tubes (2.15 per 100 TD’s) and Unplanned extubations (1.32 per 100 TD’s) were the most common airway accidents. Conclusion: The overall incidence of airway accidents was 3.82/ 100 TD’s and 7.04% of patients with no significant difference between STI vs. LTI and endotracheal tube vs. tracheostomy. Control of the airway with the help of a tracheal tube is an important aspect of intensive care. The use of tracheal tubes however is not without complications. The longer a tube stays in-situ, the greater the chances of kinking, blockade and unplanned extubations. All of the above can lead to hypoventilation and hypoxia which are potentially life threatening. The few studies on unplanned extubations have reported an incidence ranging from 0.3 - 30% .1-2 Significant proportions of those who have an unplanned extubation tolerate it well and do not require reintubation. 6,8 Most of these are associated with minimal or no morbidity. 4 One study of 53 patients however

A reply

May we thank Drs Lee and Morris for their interest in our study. They essentially raise two points: 1 calculation for the sample size for the study; 2 whether or not the study should have been extended. We are pleased to respond to both these issues as follows. We are uncertain regarding what Drs Lee and Morris actually mean by ‘suitable power calculation’. In the formulae that they have presented it is not clear what each number stands for. In the absence of such essential information we find it difficult to infer whether the formulae are actually designed for nonparametric categorical data; we suspect not. For the calculation of the sample size in the study, we used the normogram and methodology for the categorical data which have a binary outcome variable as described in the textbook by D. G. Altman (i.e. yes or no for gastro-oesophageal reflux [GOR]) [1]. On the basis of published evidence we expected the incidence of GOR of 40% and 10% for two different groups, respectively. Thus the proportions to be compared were 0.40 (P1) and 0.10 (P2). With these specified values of proportions, we calculated the standardised difference as (P1 − P2) divided by the square root of P3 (1 − P3) where P3 = (P1 + P2)/2. The standardised difference was 0.7. For an 80% probability of detection of difference at significance level of 5%, the normogram gives a sample size of ≈ 60, with 30 in each group. Therefore, we fail to see how we can agree to the suggestion that the number of patients in our study was ‘woefully inadequate’. This suggestion, in our opinion, is woefully misplaced. Another point they make is that the study ‘does not clarify in any way whether the use of a laryngeal mask is or is not a suitable alternative practice to tracheal intubation for day case gynaecological laparoscopic procedures’. Where did we claim that the study aimed to do so? In order to answer the question which Lee and Morris ask, the following need to be considered: (a) is the LMA associated with more risk of GOR when compared with a tracheal tube; (b) does increased GOR detected in the lower oesophagus of fasted patients translate into increased incidence of regurgitation in the pharynx. Our study was aimed at addressing only the former point. Because we found no incidence of GOR in the LMA group (zero out of 30) when compared with a 13% incidence in the tracheal tube group (four out of 30), we feel that it is reasonable to conclude that LMA is not associated with a higher incidence of reflux when compared with a tracheal tube in the circumstances in our study. The question then arises, would the results be any different if one recruited over 800 patients as suggested by Lee and Morris. Who knows? The question we wish to raise is whether it is worth extending the study to over 800 patients to prove that the use of tracheal tubes is associated with a slightly higher risk of GOR (as compared to LMA) when the airway in these patients is protected anyway. The 0% incidence of GOR in the LMA group, statistically, gives 95% confidence that the chance of such an event is likely to be less that 10% [2].

Modelling the mechanical effects of tracheal tubes in normal subjects.

The addition of tracheal tubes to the respiratory system contributes an extra mechanical burden in terms of pressure necessary to overcome its own resistance. On the basis of experimental data from the literature and on a previously reported mathematical model of the inspirogram, we wished to study predictions of pressures, volume, flow and work of breathing during the use of tracheal tubes. The present investigation indicates that: 1) the loss in volume is greater at the beginning of inspiration and with narrower tubes; 2) in order to preserve tidal volume the inspiratory drive must be increased at any time during inspiration with the use of diminishing internal diameter of the tubes; 3) alternatively, tidal volume can be maintained by increasing inspiratory duration; and 4) the addition of tubes with internal diameter of 9 mm (no.9) and 8 mm (no. 8) increases the total resistive work by 115 and 154%, respectively, whilst total elastic work decreases 9 and 16% in relation to the nonintubated patient. These findings are consequent to the turbulent flow pattern that normally occurs within the tracheal tubes and connectors themselves. We believe they are relevant to the physician confronted with a patient needing tracheal intubation.