Prevention of complications from prolonged tracheal intubation

A Prospective Randomized Controlled Trial of the Effect of Maintenance of Continuous Cuff Pressures (20 cmH2O vs 30 cmH2O) on Postoperative Airway Symptoms in Laparoscopic Surgeries

INTRODUCTION

Recently, laparoscopic surgery has been used in many fields of surgery. It has been reported that cuff pressure becomes high during laparoscopic surgery. Increased cuff pressure may cause postoperative sore throat and hoarseness. Considering previous reports, we hypothesized that maintenance of a fixed low cuff pressure during laparoscopic surgery might be associated with low grades of postoperative sore throat and hoarseness.

METHODS

The participants were 100 patients between 20 and 80 years of age who were scheduled to undergo laparoscopic surgery lasting over 2 hours. Patients were randomly allocated to two groups with endotracheal tube cuff pressures fixed at 20 cmH2O (low-pressure group; LPG) and 30 cmH2O (high-pressure group; HPG). We evaluated mainly sore throat and hoarseness on postoperative day 1 using a visual analog scale (VAS; 0-10 cm). Statistical comparisons of values were performed using the unpaired t-test, Mann-Whitney U-test, and chi-square test with values of p < 0.05 considered statistically significant.

RESULTS

There were no significant differences in background characteristics between the two groups. Median postoperative scores for the LPG and HPG were 1 (interquartile range, 0-3) and 0 (0-2; p = 0.560) for sore throat and 2 (0-4) and 1 (0-3; p = 0.311) for hoarseness, respectively, and the differences were not significant.

CONCLUSION

The effects of maintenance of a fixed low cuff pressure and a fixed high cuff pressure on the degrees of postoperative sore throat and hoarseness after laparoscopic surgery were the same and the grades were low.

Impact of Low-Volume, Low-Pressure Tracheostomy Cuffs on Acute Mucosal Injury in Swine

OBJECTIVE

Tapered low-volume, low-pressure (LVLP) cuffs have been introduced to improve sealing and reduce injury from tracheostomy and endotracheal intubation compared to traditional cylindrical high-volume, low-pressure (HVLP) cuffs. The objective of this study is to develop a swine model of tracheostomy injury and to compare live tissue response following LVLP and HVLP tracheostomy placement.

STUDY DESIGN

In vivo animal study.

SETTING

Academic institution.

METHODS

Swine underwent tracheostomy followed by placement of LVLP and HVLP tracheostomy cuffs at 30 cm H2O. After 24 and 48 hours, tracheal specimens underwent histopathological analysis including cilia, lamina propria and epithelial thickness, and mucosal injury score.

RESULTS

In all cuff contact areas, mean epithelial thickness for both tracheostomy cohorts was decreased compared to control epithelium at 24 and 48 hours (P < .01). HVLP proximal epithelium thickness was decreased at 24 and 48 hours relative to LVLP sections (P < .05). Lamina propria thickness in proximal LVLP sections was less than HVLP sections at 24 hours and 48 hours (P < .05). Mucosal injury score at areas of cuff contact was increased in tracheostomy cohorts relative to controls (P < .001), with HVLP injury score greater than LVLP at the proximal cuff (P < .05).

CONCLUSION

In a swine model, tracheostomy resulted in increased mucosal injury compared to normal tracheal mucosa. LVLP cuffs resulted in less injury than HVLP cuffs, with reduced mucosal inflammation and improved health of epithelium and lamina propria. The wider proximal LVLP cuff demonstrated improved mucosal health compared to the HVLP cylindrical cuff.

Laryngotracheal injuries after intubation in pediatric seizure patients: A case series and a review of the literature

Acute management of seizures may require intubation with an endotracheal tube (ETT) in addition to benzodiazepine administration. Although necessary for management at times, intubation can lead to laryngotracheal injury as has been reported at length in both the adult and pediatric populations. A review of the literature shows no prior reports of laryngotracheal injuries following intubation in actively seizing pediatric patients. We share our experience with two pediatric patients who had laryngotracheal injuries after being emergently intubated with large ETT's during management of their seizures. We describe two unique cases in the pediatric seizure population associated with laryngotracheal injuries with the goal of emphasizing appropriate ETT sizing for intubation.

What is the Adequate Cuff Volume for Tracheostomy Tube? A Pilot Cadaver Study

OBJECTIVE

To determine the patterns of tracheostomy cuff pressure changes with various air inflation amounts in different types of tracheostomy tubes to obtain basic data for appropriately managing long-term tracheostomy.

METHODS

We performed tracheostomy on a 46-year-old male cadaver. Three types of tracheostomy tubes (single-cuffed, double-cuffed, and adjustable flange), divided into 8 different subtypes based on internal tube diameters and cuff diameters, were inserted into the cadaver. Air was inflated into the cuff, and starting with 1 mL air, the cuff pressure was subsequently measured using a manometer.

RESULTS

For the 7.5 mm/14 mm tracheostomy tube, cuff inflation with 3 mL of air yielded a cuff pressure within the recommended range of 20-30 cmH2O. The 7.5 mm/24 mm tracheostomy tube showed adequate cuff pressure at 5 mL of air inflation. Similar values were observed for the 8.0 mm/16 mm and 8.0 mm/27 mm tubes. Double-cuffed tracheostomy cuff pressures (7.5 mm/20 mm and 8.0 mm/20 mm tubes) at 3 mL air inflation had cuff pressures of 18-20 cmH2O at both the proximal and distal sites. For the adjustable flange tracheostomy tube, cuff pressure at 6 mL of cuff air inflation was within the recommended range. Maximal cuff pressure was achieved at inflation with almost 14 mL of air, unlike other tube types.

CONCLUSION

Various types of tracheostomy tubes showed different cuff pressures after inflation. These values might aid in developing guidelines For patients who undergo tracheostomy and are discharged home without cuff pressure manometers, this standard might be helpful to develop guidelines.

Efficacy of Automatic Retention Pressure of a Double-Lumen Tube Cuff: An Artificial Intubation Model

BACKGROUND

The movement of a double-lumen endotracheal tube (DLT) out of its appropriate position during thoracic surgery can result in the loss of one-lung ventilation (OLV), especially during pulmonary resection and node dissection. Our study aimed to validate the efficacy of automatic retention pressure control of the DLT bronchial cuff in maintaining OLV in an artificial intubation model.

MATERIALS AND METHODS

A 35-Fr left-sided DLT was intubated to the left main bronchus in an intubation simulator and connected to an anesthesia machine. The inspiratory volume, respiratory rate, and inspiratory-expiratory ratio were set at 500 mL, 12 times/min, and 1:2, respectively. A 1-kg right main bronchial traction in the lateral right was provided after OLV was established. SmartCuff (Smiths Medical, Minneapolis, Minnesota, USA) was used to maintain cuff pressure. The efficacy of retention pressure with SmartCuff (Group S) and without SmartCuff (Group WS) was compared. The primary outcome was the rate of tidal volume (TV) reduction following bronchial traction in the two groups.

RESULTS

The TVs were 289.8 ± 28.9 mL and 242.8 ± 31.9 mL in Group S and Group WS, respectively (P = 0.003). The rate of TV reduction after bronchial traction was significantly lower in Group S (29 ± 5%) than in Group WS (43 ± 6%) (P < 0.001).

CONCLUSIONS

Automatic retention pressure control of the DLT bronchial cuff improves the rate of TV reduction during right main bronchial traction in an artificial intubation model. Continuous retention cuff pressure may be useful in maintaining OLV during thoracic surgery.

A Prospective, Ex Vivo Trial of Endobronchial Blockade Management Utilizing 3 Commonly Available Bronchial Blockers

BACKGROUND

Lung isolation with bronchial blockers is a well-described and accepted procedure, often described for use during the management of massive hemoptysis. Recommendations for balloon inflation are sparse, with some advocating for saline whereas other suggest air, including the manufacturers. We sought to evaluate the optimal method for balloon inflation in an ex vivo trial.

METHODS

We performed a prospective trial utilizing 3 commercially available bronchial blockers commonly described for use in lung isolation and massive hemoptysis management. We utilized the Arndt Endobronchial Blocker (Cook Medical), the Cohen Tip Deflecting Endobronchial Blocker (Cook Medical), and the Fogarty Venous Thrombectomy Catheter (Edwards LifeSciences). Balloon size and deflation assessment were tested within 3 different scenarios comparing air versus saline.Welch t test was performed to compare means between groups, and a generalized estimating equation model was utilized to compare balloon diameter over time to account for correlation among repeated measures from the same balloon.

RESULTS

All 3 endobronchial blocker systems were observed in triplicate. During free-standing balloon inflation, all 3 endobronchial systems displayed a greater degree of balloon deflation over time with air as opposed to saline (P < .001). Within a stent-based model, inflation with air of all 3 endobronchial systems, according to manufacturer recommendations, demonstrated significantly decreased time until fluid transgression occurred when compared to a saline model (P < .001). Within a stent-based model, inflation with air, according to clinical judgment, demonstrated significantly decreased time until fluid transgression in the Arndt (P = .016) and the Fogarty (P < .001) system, but not the Cohen (P = .173) system, when compared with saline.

CONCLUSIONS

The utilization of saline for balloon inflation during bronchial blockade allows for more consistent balloon inflation. The use of saline during balloon inflation appears to delay passive, spontaneous balloon deflation time when compared to air during a model of endobronchial blockade. The approach of saline inflation should be tested in humans to demonstrate the overall applicability and validity of the current findings.

Effect of lateral positioning on the bronchial cuff pressure of a left-sided double-lumen endotracheal tube during thoracic surgery: study protocol for a prospective observational study

INTRODUCTION

Correct pressure is important when using a double-lumen endotracheal tube (DLT), especially in thoracic surgery. An inadequate bronchial cuff pressure (BCP) can cause air leak and interfere with visualisation of the surgical field, whereas an excessive pressure BCP can lead to cuff-related complications. Based on several reports that cuff pressure could alter after a positional change when using an endotracheal tube, we hypothesise that a change from the supine position to the lateral decubitus position, which is essential for thoracic surgery, would affect the BCP of the DLT.

METHODS AND ANALYSIS

This prospective, single-centre, observational study will enrol 74 patients aged 18-70 years undergoing elective lung surgery from September 2018 to April 2019. The primary outcome will be the change in the 'initially established BCP' (maximum BCP not exceeding 40 cm H₂O with no air leak in the supine position) after lateral decubitus positioning. BCP and air leak will be assessed in each patient position during inflation of the cuff with air in 0.5 mL increments from 0 to 3 mL. Secondary outcomes will include the incidence of BCP exceeding 40 cm H₂O after the initial established value and that of a change in the smallest bronchial cuff volume without air leak after a change to the lateral position. The relationship between the change in BCP and airway pressure, compliance and body mass index after lateral positioning will be investigated.

ETHICS AND DISSEMINATION

The study will be conducted in accordance with the Declaration of Helsinki and supervised by the Daegu Catholic University Medical Center institutional review board (study approval number CR-18-111). All patients will receive information about the study and will need to provide written informed consent before enrolment. The results will be presented at an international meeting and published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03656406; Pre-results.

Endotracheal Tube Cuff Pressures in Patients Intubated Prior to Helicopter EMS Transport

Introduction

Endotracheal intubation is a common intervention in critical care patients undergoing helicopter emergency medical services (HEMS) transportation. Measurement of endotracheal tube (ETT) cuff pressures is not common practice in patients referred to our service. Animal studies have demonstrated an association between the pressure of the ETT cuff on the tracheal mucosa and decreased blood flow leading to mucosal ischemia and scarring. Cuff pressures greater than 30 cmH₂O impede mucosal capillary blood flow. Multiple prior studies have recommended 30 cmH₂O as the maximum safe cuff inflation pressure. This study sought to evaluate the inflation pressures in ETT cuffs of patients presenting to HEMS.

Methods

We enrolled a convenience sample of patients presenting to UMass Memorial LifeFlight who were intubated by the sending facility or emergency medical services (EMS) agency. Flight crews measured the ETT cuff pressures using a commercially available device. Those patients intubated by the flight crew were excluded from this analysis as the cuff was inflated with the manometer to a standardized pressure. Crews logged the results on a research form, and we analyzed the data using Microsoft Excel and an online statistical analysis tool.

Results

We analyzed data for 55 patients. There was a mean age of 57 years (range 18–90). The mean ETT cuff pressure was 70 (95% CI= [61–80]) cmH₂O. The mean lies 40 cmH₂O above the maximum accepted value of 30 cmH₂O (p<0.0001). Eighty-four percent (84%) of patients encountered had pressures above the recommended maximum. The most frequently recorded pressure was >120 cmH₂O, the maximum pressure on the analog gauge.

Conclusion

Patients presenting to HEMS after intubation by the referral agency (EMS or hospital) have ETT cuffs inflated to pressures that are, on average, more than double the recommended maximum. These patients are at risk for tracheal mucosal injury and scarring from decreased mucosal capillary blood flow. Hospital and EMS providers should use ETT cuff manometry to ensure that they inflate ETT cuffs to safe pressures.

Prolonged Intubation Versus Tracheostomy in the Adult

The development of mechanical ventilators that can en sure adequate respiration for long periods of time has led to the problem of determining how to best integrate patients into the machine's airflow circuits. Tracheal tubes with inflatable cuffs efficiently connect the patient to the machine, but the tubes may be placed in one of two ways. Each option has relative advantages and disad vantages. Translaryngeal intubation (TLI) can be per formed safety and quickly and is the preferred first step in airway management. However, when TLI is needed for prolonged periods, it may damage the larynx. Tra cheostomy, on the otherhand, has potential operative and tracheal complications, but presents little risk to the larynx and may be better tolerated by the patient requir ing long-term intubation. This review provides a histor ical background of these two methods and analyzes their respective advantages and complications. Guide lines for the optimal use of TLI and tracheostomy, par ticularly in adult patients requiring long-term intuba tion, are developed by comparing the risks and benefits of these two methods.

Bronchial blockers under pressure: in vitro model and ex vivo model

BACKGROUND

Pressures (Pe) exerted by bronchial blockers on the inner wall of the bronchi may cause mucosal ischaemia. Our aims were as follows: (i) to compare the intracuff pressure (Pi) and Pe exerted by commercially available bronchial blockers in an in vitro and an ex vivo model; (ii) to investigate the influence of both the inflated intracuff volume and cuff diameter on Pe; and (iii) to estimate the minimal sealing volume (VSmin) and the corresponding Pe for each bronchial blocker studied.

METHODS

The Pe exerted by seven commercial bronchial blockers was measured at different inflation volumes using a custom-designed system using in vitro and ex vivo animal models with two internal diameters (12 and 15 mm).

RESULTS

In the same conditions, Pi was significantly lower than Pe (P<0.05), and Pe was higher in the in vitro model than in the ex vivo model. The Pe increased with the inflated volume, with use of the small-diameter model (P<0.05). Ex vivo models needed a higher minimal sealing volume than the in vitro models, and this volume increased with the diameter (e.g. the VSmin at a positive pressure of 25 cm H2O required a Pe ranging from 12 to 78 mm Hg on the 15 mm ex vivo model and from 66 to 110 mm Hg on the 12 mm ex vivo model).

CONCLUSIONS

The Pi cannot be used to approximate Pe. The diameter of the model, the inflated volume, and the bronchial blocker design all influence Pe. A pressure higher than the critical ischaemic threshold (i.e. 25 mm Hg) was needed to prevent air leak around the cuff in the in vitro and ex vivo models.

In vitro evaluation of the method effectiveness to limit inflation pressure cuffs of endotracheal tubes

BACKGROUND AND OBJECTIVE

Cuffs of tracheal tubes protect the lower airway from aspiration of gastric contents and facilitate ventilation, but may cause many complications, especially when the cuff pressure exceeds 30cm H2O. This occurs in over 30% of conventional insufflations, so it is recommended to limit this pressure. In this study we evaluated the in vitro effectiveness of a method of limiting the cuff pressure to a range between 20 and 30cm H2O.

METHOD

Using an adapter to connect the tested tube to the anesthesia machine, the relief valve was regulated to 30cm H2O, inflating the cuff by operating the rapid flow of oxygen button. There were 33 trials for each tube of three manufacturers, of five sizes (6.5-8.5), using three times inflation (10, 15 and 20s), totaling 1485 tests. After inflation, the pressure obtained was measured with a manometer. Pressure >30cm H2O or <20cm H2O were considered failures.

RESULTS

There were eight failures (0.5%, 95% CI: 0.1-0.9%), with all by pressures <20cm H2O and after 10s inflation (1.6%, 95% CI: 0 5-2.7%). One failure occurred with a 6.5 tube (0.3%, 95% CI: -0.3 to 0.9%), six with 7.0 tubes (2%, 95% CI: 0.4-3.6%), and one with a 7.5 tube (0.3%, 95% CI: -0.3 to 0.9%).

CONCLUSION

This method was effective for inflating tracheal tube cuffs of different sizes and manufacturers, limiting its pressure to a range between 20 and 30cm H2O, with a success rate of 99.5% (95% CI: 99.1-99.9%).

An overview of complications associated with open and percutaneous tracheostomy procedures

Tracheostomy, whether open or percutaneous, is a commonly performed procedure and is intended to provide long-term surgical airway for patients who are dependent on mechanical ventilatory support or require (for various reasons) an alternative airway conduit. Due to its invasive and physiologically critical nature, tracheostomy placement can be associated with significant morbidity and even mortality. This article provides a comprehensive overview of commonly encountered complications that may occur during and after the tracheal airway placement, including both short- and long-term postoperative morbidity.

Effectiveness of the endotracheal tube cuff on the trachea: physical and mechanical aspects

Introduction

The inflation pressure of the endotracheal tube cuff can cause ischemia of the tracheal mucosa at high pressures; thus, it can cause important tracheal morbidity and tracheal microaspiration of the oropharyngeal secretion, or it can even cause pneumonia associated with mechanical ventilation if the pressure of the cuff is insufficient.

Objective

In order to investigate the effectiveness of the RUSCH® 7.5 mm endotracheal tube cuff, this study was designed to investigate the physical and mechanical aspects of the cuff in contact with the trachea.

Methods

For this end, we developed an in vitro experimental model to assess the flow of dye (methylene blue) by the inflated cuff on the wall of the artificial material. We also designed an in vivo study with 12 Large White pigs under endotracheal intubation. We instilled the same dye in the oral cavity of the animals, and we analyzed the presence or not of leakage in the trachea after the region of the cuff after their deaths (animal sacrifice). All cuffs were inflated at the pressure of 30 cmH₂O.

Results

We observed the passage of fluids through the cuff in all in vitro and in vivo experimental models.

Conclusion

We conclude that, as well as several other cuff models in the literature, the RUSCH® 7.5 mm tube cuffs are also not able to completely seal the trachea and thus prevent aspiration of oropharyngeal secretions. Other prevention measures should be taken.

Design and characterization of a measurement system for monitoring pressure exerted by bronchial blockers: In vitro trials

Bronchial blockers (BBs) allow occluding the bronchial duct and collapsing the "dependent" lung in a number of thoracic surgery. The occlusion is obtained through a cuff that, inflated with a proper air volume, exerts a pressure, Pe, on the inner wall of the mainstem bronchus. In this work a measurement chain, based on two piezorestistive force sensors, was developed and calibrated to measure Pe exerted by six BBs, as a function of inflated volume on in vitro models (two latex ducts with diameters similar to the ones of the adult mainstem bronchi: 12 mm and 15 mm). Pe showed wide changes considering different BBs, and significantly increases with the decrease of the model's diameter, at the same inflated volume. Lastly, the minimum occlusive volume (MOV) to sail the two models was estimated for each BB. These experiments were performed by applying a pressure difference across the cuff of 25 cmH2O, in order to simulate the worst condition in a clinical scenario. Results show that MOV depends on both the type of BB and the duct diameter. The knowledge of this volume allows estimating the minimum value of Pe exerted by BBs to avoid air leakage.

[In vitro evaluation of the method effectiveness to limit inflation pressure cuffs of endotracheal tubes]

BACKGROUND AND OBJECTIVE

Cuffs of tracheal tubes protect the lower airway from aspiration of gastric contents and facilitate ventilation, but may cause many complications, especially when the cuff pressure exceeds 30cm H2O. This occurs in over 30% of conventional insufflations, so it is recommended to limit this pressure. In this study we evaluated the in vitro effectiveness of a method of limiting the cuff pressure to a range between 20 and 30cm H2O.

METHOD

Using an adapter to connect the tested tube to the anesthesia machine, the relief valve was regulated to 30cm H2O, inflating the cuff by operating the rapid flow of oxygen button. There were 33 trials for each tube of three manufacturers, of five sizes (6.5 to 8.5), using three times inflation (10, 15 and 20seconds), totaling 1485 tests. After inflation, the pressure obtained was measured with a manometer. Pressure >30cm H2O or <20cm H2O were considered failures.

RESULTS

There were eight failures (0.5%, 95% CI: 0.1-0.9%), with all by pressures <20cm H2O and after 10seconds inflation (1.6%, 95% CI: 0 5-2.7%). One failure occurred with a 6.5 tube (0.3%, 95% CI: -0.3-0.9%), six with 7.0 tubes (2%, 95% CI: 0.4 to 3.6%), and one with a 7.5 tube (0.3%, 95% CI: -0.3-0.9%).

CONCLUSION

This method was effective for inflating tracheal tube cuffs of different sizes and manufacturers, limiting its pressure to a range between 20 and 30cm H2O, with a success rate of 99.5% (95% CI: 99.1-99.9%).

Subglottic secretion drainage and continuous control of cuff pressure used together save health care costs

BACKGROUND

Preventive strategies to reduce ventilator-associated respiratory infection (VARI) include the use of an endotracheal tube incorporating a lumen for subglottic secretion drainage (SSD) and a system for continuous control of endotracheal tube cuff pressure (CCCP). The health care costs associated with the combined use of these 2 measures aimed at preventing VARI are not known, however. The objective of this study was to determine whether the simultaneous use of these 2 preventive measures for VARI could save health care costs.

METHODS

We performed a prospective observational study of patients who needed mechanical ventilation in an intensive care unit. The health care costs considered here included only the costs of the endotracheal tube, cuff control, and antimicrobials used to treat VARI.

RESULTS

The study cohort comprised 656 patients, including 241 with intermittent control of cuff pressure and without SSD (standard group), 260 with CCCP and without SSD (CCCP group), 84 with intermittent control of cuff pressure and with SSD (SSD group), and 71 with CCCP and SSD (CCCP + SSD group). The incidence of VARI and health care costs were lower in the CCCP + SSD group compared with the standard, CCCP, and SSD groups.

CONCLUSIONS

The combined use of SSD and CCCP reduced the incidence of VARI and saved health care costs.

Surgical Excision of Postintubation Granuloma Under Jet Ventilation

Following the use of an endotracheal or tracheostomy tube, circumferential lesions, stenosis, or granulomatous lesions at the cuff level or tip of the tube may be observed on the tracheal wall. This injury mainly occurs due to excessive pressure of the cuff on the tracheal wall and may be prevented by a high-volume, low-pressure cuff and a carefully monitored tracheostomy tube. Although there is an overall improvement in the design of high-volume cuffs, hyperinflation of these cuffs may still contribute to tracheal injuries. If the size of the granuloma is limited, the lesion is treated by excision (microlaryngeal surgery) under general anaesthesia. Using jet ventilation during the operation minimizes the trauma caused by intubation and reduces the risk of oedema and the risk of barotrauma, as it provides ventilation over a possible stenosis. In addition to providing better visualization of the surgical field and superior surgeon comfort, jet ventilation also increases the success of the operation. In this case report, we aimed to present a successful anaesthesia technique performed by jet ventilation in a patient with a postintubation granuloma, which was excised by microlaryngeal surgery without the need for reintubation.

Continuous endotracheal tube cuff pressure control system protects against ventilator-associated pneumonia

INTRODUCTION

The use of a system for continuous control of endotracheal tube cuff pressure reduced the incidence of ventilator-associated pneumonia (VAP) in one randomized controlled trial (RCT) with 112 patients but not in another RCT with 142 patients. In several guidelines on the prevention of VAP, the use of a system for continuous or intermittent control of endotracheal cuff pressure is not reviewed. The objective of this study was to compare the incidence of VAP in a large sample of patients (n = 284) treated with either continuous or intermittent control of endotracheal tube cuff pressure.

METHODS

We performed a prospective observational study of patients undergoing mechanical ventilation during more than 48 hours in an intensive care unit (ICU) using either continuous or intermittent endotracheal tube cuff pressure control. Multivariate logistic regression analysis (MLRA) and Cox proportional hazard regression analysis were used to predict VAP. The magnitude of the effect was expressed as odds ratio (OR) or hazard ratio (HR), respectively, and 95% confidence interval (CI).

RESULTS

We found a lower incidence of VAP with the continuous (n = 150) than with the intermittent (n = 134) pressure control system (22.0% versus 11.2%; p = 0.02). MLRA showed that the continuous pressure control system (OR = 0.45; 95% CI = 0.22-0.89; p = 0.02) and the use of an endotracheal tube incorporating a lumen for subglottic secretion drainage (SSD) (OR = 0.39; 95% CI = 0.19-0.84; p = 0.02) were protective factors against VAP. Cox regression analysis showed that the continuous pressure control system (HR = 0.45; 95% CI = 0.24-0.84; p = 0.01) and the use of an endotracheal tube incorporating a lumen for SSD (HR = 0.29; 95% CI = 0.15-0.56; p < 0.001) were protective factors against VAP. However, the interaction between type of endotracheal cuff pressure control system (continuous or intermittent) and endotracheal tube (with or without SSD) was not statistically significant in MLRA (OR = 0.41; 95% CI = 0.07-2.37; p = 0.32) or in Cox analysis (HR = 0.35; 95% CI = 0.06-1.84; p = 0.21).

CONCLUSIONS

The use of a continuous endotracheal cuff pressure control system and/or an endotracheal tube with a lumen for SSD could help to prevent VAP in patients requiring more than 48 hours of mechanical ventilation.

Inspiratory muscle training did not accelerate weaning from mechanical ventilation but did improve tidal volume and maximal respiratory pressures: a randomised trial

QUESTION

Does inspiratory muscle training accelerate weaning from mechanical ventilation? Does it improve respiratory muscle strength, tidal volume, and the rapid shallow breathing index?

DESIGN

Randomised trial with concealed allocation and intention-to-treat analysis.

PARTICIPANTS

92 patients receiving pressure support ventilation were included in the study and followed up until extubation, tracheostomy, or death.

INTERVENTION

The experimental group received usual care and inspiratory muscle training using a threshold device, with a load of 40% of their maximal inspiratory pressure with a regimen of 5 sets of 10 breaths, twice a day, 7 days a week. The control group received usual care only.

OUTCOME MEASURES

The primary outcome was the duration of the weaning period. The secondary outcomes were the changes in respiratory muscle strength, tidal volume, and the rapid shallow breathing index.

RESULTS

Although the weaning period was a mean of 8 hours shorter in the experimental group, this difference was not statistically significant (95% CI -16 to 32). Maximal inspiratory and expiratory pressures increased in the experimental group and decreased in the control group, with significant mean differences of 10cmH2O (95% CI 5 to 15) and 8cmH2O (95% CI 2 to 13), respectively. The tidal volume also increased in the experimental group and decreased in the control group (mean difference 72 ml, 95% CI 17 to 128). The rapid shallow breathing index did not differ significantly between the groups.

CONCLUSION

Inspiratory muscle training did not shorten the weaning period significantly but it increased respiratory muscle strength and tidal volume.

Optimal degree of mouth opening for laryngeal mask airway function during oral surgery

PURPOSE

This study was performed to determine the optimal degree of mouth opening in anesthetized patients requiring laryngeal mask airway (LMA) during oral surgery.

PATIENTS AND METHODS

A single, experienced LMA user inserted the LMA in 15 patients who were scheduled for elective oral surgery. Oropharyngeal leak pressure, intracuff pressure, and fiberoptic assessment of the LMA position were sequentially documented in 5 mouth conditions-opening of 1.4 (neutral position), 2, 3, 4, and 5 cm-and any resulting ventilatory difficulties were recorded.

RESULTS

Oropharyngeal leak pressure with the mouth open 4 cm (21.8 ± 3.2 cm H(2)O, P = .025) and 5 cm (27.3 ± 7.2 cm H(2)O, P < .001) was significantly higher than in the neutral position (18.1 ± 1.5 cm H(2)O), as was intracuff pressure (neutral position, 60.0 ± 0 cm H(2)O; 4 cm, 72.6 ± 5.1 cm H(2)O [P < .001]; and 5 cm, 86.9 ± 14.4 cm H(2)O [P < .001]). LMA position, observed by fiberoptic bronchoscopy, was unchanged by mouth opening, being similar in the 5 mouth conditions (P = .999). In addition, ventilation difficulties (abnormal capnograph curves or inadequate tidal volume) occurred in 2 of 15 patients (13%) and 7 of 15 patients (53%) (P < .001) with the mouth opening of 4 and 5 cm, respectively.

CONCLUSIONS

This study showed that a mouth opening over 4 cm led to substantial increases in oropharyngeal leak pressure and intracuff pressure of the LMA, warranting caution, because gastric insufflation, sore throat, and ventilation difficulties may occur. A mouth opening of 3 cm achieves acceptable airway conditions for anesthetized patients requiring LMA.

New issues and controversies in the prevention of ventilator-associated pneumonia

In the past 2 years, American, Canadian, and European scientific societies have published their new evidence-based guidelines for ventilator-associated pneumonia (VAP) prevention. However, these guidelines did not review some potentially useful strategies, such as the use of an endotracheal tube with an ultrathin cuff membrane, an endotracheal tube with a low-volume/low-pressure cuff, a device for continuous monitoring of the endotracheal tube cuff pressure, a device to remove biofilm from the inner site of the endotracheal tube, and saline instillation before tracheal suctioning. Only a few guidelines analyze the time of tracheostomy, and so no firm recommendations can be made regarding its importance. In addition, the guidelines diverge on the use of heat and moisture exchangers or heated humidifiers and on the use of an endotracheal tube coated with antimicrobial agents. The current review focuses on measures of VAP prevention for which there is no clear recommendation, or the use of which is controversial. A review of the literature suggests that the use of an endotracheal tube with an ultrathin and tapered-shape cuff membrane and coated in antimicrobial agents may reduce the risk of VAP. These features offer an attractive way to optimize the VAP prevention capacity of endotracheal tubes with a lumen for subglottic secretion drainage. We believe that early tracheostomy should be considered, based on the length reduction of mechanical ventilation and intensive care unit stay, reduction of mortality, and on patient comfort, although early tracheostomy has not yet been shown to favorably impact the incidence of VAP. We believed that heat and moisture exchangers should be considered based on the benefits in terms of cost savings. More research is necessary to clarify the role of continuous cuff pressure monitoring, removal of biofilm formation in the endotracheal tubes, and routine saline instillation before tracheal suctioning.

Ventilator-associated pneumonia: current status and future recommendations

OBJECTIVE

Ventilator-associated pneumonia (VAP) is a common hazardous complication in ICU patients. The aim of the current review is to give an update on the current status and future recommendations for VAP prevention.

METHODS

This article gives an updated review of the current literature on VAP. The first part briefly reviews pathogenesis and epidemiology while the second includes an in-depth review of evidence-based practice guidelines (EBPG) and new technologies developed for prevention of VAP.

RESULTS

VAP remains a frequent and costly complication of critical illness with a pooled relative risk of 9-27% and mortality of 25-50%. Strikingly, VAP adds an estimated cost of more than $40,000 to a typical hospital admission. An important aetiological mechanism of VAP is gross or micro-aspiration of oropharyngeal organisms around the cuff of the endotracheal tube (ETT) into the distal bronchi. Prevention of VAP is preferable. Preventative measures can be divided into two main groups: the implemen- tation of EBPGs and use of device-based technologies. EBPGs have been authored jointly by the American Thoracic Society and the Infectious Diseases Society of America. The Canadian Critical Care Trials group also published VAP Guidelines in 2008. Their recommendations are detailed in this review. The current device-based technologies include drainage of subglottic secretions, silver coated ETTs aiming to influence the internal bio-layer of the ETT, better sealing of the lower airways with ultrathin cuffs and loops for optimal cuff pressure control.

CONCLUSIONS

EBPG consensus includes: elevation of the head of the bed, use of daily "sedation vacations" and decontamination of the oropharynx. Technological solutions should aim to use the most comprehensive combination of subglottic suction of secretions, optimization of ETT cuff pressure and ultrathin cuffs. VAP is a type of hospital-acquired pneumonia that develops more than 48 h after endotracheal intubation. Its incidence is estimated to be 9-27%, with a mortality of 25-50% [Am J Respir Crit Care Med 171:388-416 (2005), Am J Med 85:499-506 (1988), Chest 122:2115-2121 (2002), Intensive Care Med 35:9-29 (2009)]. The most important target in VAP handling is its prevention. The aim of this article is to review the pathogenesis, epidemiology and the different strategies/technologies for prevention of VAP.

The influence of mouth opening on oropharyngeal leak pressure, intracuff pressure, and cuff position with the laryngeal mask airway

PURPOSE

The aim of this study was to investigate the influence of mouth opening on oropharyngeal leak pressure, intracuff pressure, and cuff position of the laryngeal mask airway (LMA).

PATIENTS AND METHODS

Fifteen patients who were scheduled for elective oral surgery were recruited into this study. A single, experienced LMA user inserted the LMA according to the manufacturer's recommended technique. Oropharyngeal leak pressure, intracuff pressure, and fiberoptic assessment of the LMA position were documented under 3 mouth conditions: neutral position (1.4-cm distance between upper and lower incisors), mouth open (5- to 6-cm distance between upper and lower incisors), and return to the neutral position. Any ventilation difficulties under the 3 mouth conditions were recorded.

RESULTS

Oropharyngeal leak pressure with the mouth open was higher than in the neutral position (P < .001). Compared with the neutral position, intracuff pressure was also higher with the mouth open (P < .001). Both measurement values returned to control levels when the neutral position was once again assumed. The LMA position observed by fiberoptic bronchoscopy was unchanged by mouth opening and was similar in the 3 mouth conditions (P = .998). Although ventilatory difficulties occurred after mouth opening in 8 of 15 patients (P < .001), it did not occur when the neutral position was reassumed.

CONCLUSIONS

This study showed that mouth opening led to substantial increases in oropharyngeal leak pressure and intracuff pressure of the LMA, warranting caution because gastric insufflation, sore throat, and ventilation difficulties may occur.

Tracheostomy Tube-induced Tracheoesophageal Fistula

Tracheostomy is one of the most common elective surgical procedures performed in critically ill patients. The complications of tracheostomy may be categorized on the basis of duration from the procedure: early-intraoperative, medium-early postoperative, and late postoperative. Tracheoeosphageal fistula is one of the known late complications of tracheostomy. Injury to the tracheal wall can occur because of high cuff pressure or direct mechanical trauma from the tracheostomy tube. We report a case of tracheoeosphageal fistula caused by a cuffless tracheostomy tube that was managed by an endobronchial stent.

Influence of an Endotracheal Tube with Polyurethane Cuff and Subglottic Secretion Drainage on Pneumonia

RATIONALE

Subglottic secretion drainage (SSD) appears to be effective in preventing ventilator-associated pneumonia (VAP), primarily by reducing early-onset pneumonia; but it may not prevent late-onset pneumonia. We tested the hypothesis using an endotracheal tube incorporating an ultrathin polyurethane cuff (which reduces channel formation and fluid leakage from the subglottic area), in addition to an SSD lumen, which would reduce the incidence of late-onset VAP.

OBJECTIVES

To compare the incidence of VAP, using an endotracheal tube with polyurethane cuff and subglottic secretion drainage (ETT-PUC-SSD) versus a conventional endotracheal tube (ETT-C) with polyvinyl cuff, without subglottic secretion drainage.

METHODS

Clinical randomized trial in a 24-bed medical-surgical intensive care unit. Patients expected to require mechanical ventilation for more than 24 hours were randomly assigned to one of two groups: one was ventilated with ETT-PUC-SSD and the other with ETT-C.

MEASUREMENTS AND MAIN RESULTS

Tracheal aspirate samples were obtained during endotracheal intubation, then twice per week and finally on extubation. VAP was found in 31 of 140 (22.1%) patients in the ETT-C group and in 11 of 140 (7.9%) in the ETT-PUC-SSD group (P = 0.001). Cox regression analysis showed ETT-C as a risk factor for global VAP (hazard ratio [HR], 3.3; 95% confidence interval [CI], 1.66-6.67; P = 0.001), early-onset VAP (HR, 3.3; 95% CI, 1.19-9.09; P = 0.02), and late-onset VAP (HR, 3.5; 95% CI, 1.34-9.01; P = 0.01).

CONCLUSIONS

The use of an endotracheal tube with polyurethane cuff and subglottic secretion drainage helps prevent early- and late-onset VAP. Clinical trial registered with www.clinicaltrials.gov (NCT 00475579).

Pressures Exerted by Endobronchial Devices

BACKGROUND

High endotracheal cuff pressures have been shown to cause high mucosal pressures and a reduction in mucosal blood flow, with the risk of mucosal ischemia. We aimed to directly measure the pressure exerted by the bronchial cuffs of double-lumen tubes (DLT) and by the cuffs of three new designs of endobronchial blocker (EBB).

METHODS

Using a validated in vitro model and a previously described technique, we measured the static pressures exerted by the cuff of DLTs and EBBs with 1 mL increments in cuff volume until maximum inflation was achieved. The study was repeated under dynamic conditions of simulated positive pressure ventilation.

RESULTS

The pressures exerted by the cuffs of DLTs ranged from 16-155 mm Hg. Pressures exerted by the EBB cuffs ranged from 39-194 mm Hg. At intra-cuff volumes required to create a seal to 25 cm H2O positive pressure, the pressures exerted by the cuffs of all the devices were <30 mm Hg.

CONCLUSIONS

A transmitted pressure <30 mm Hg has been recommended to avoid mucosal injury. Our study shows that at clinically relevant cuff volumes, the pressures exerted by the cuffs do not exceed the recommended safe limit.

A case of laryngotracheal stenosis masquerading as asthma

This report describes the case of a 21-year-old male that presented in respiratory failure caused by laryngotracheal stenosis (LTS) related to remote endotracheal intubation. The patient sought treatment for respiratory complaints in the weeks prior, and had a poor response to treatment for asthma. Currently, LTS is predominantly seen as a sequela of invasive airway management, and this case highlights the possibility of delayed presentations. Clinical manifestations and methods of diagnosis are described. Preventive measures, temporizing therapy, and definitive treatment are then discussed. With increasing numbers of patients undergoing invasive airway maneuvers, it is increasingly important for providers to recognize this disease. As is shown in this case, the diagnosis of LTS requires a high clinical suspicion in order to achieve a timely diagnosis and decrease morbidity and mortality.

Optimization of endotracheal tube cuff filling by continuous upper airway carbon dioxide monitoring

Inappropriate cuff filling is responsible for various complications related to the use of an endotracheal tube (ETT). In this study, we evaluated an objective, noninvasive method for continuous assessment of leak around the ETT cuff by monitoring carbon dioxide pressure (P(CO2) in the upper airway. P(CO2) levels were measured by capnography simultaneously between the ETT cuff and the vocal cords, at the oropharynx, and in the nares of the nose. Cuff filling was regulated by an electronic controller to achieve the minimal pressure needed to prevent CO2 leak. Feasibility of the method was assessed in a human simulator and in a porcine model. Clinical function was evaluated in 60 patients undergoing surgery, comparing the method to the standard anesthesiologist evaluation. Linear correlations were observed between the ETT cuff pressure and P(CO2) level in the human simulator (R2 = 0.954, P < 0.0001) and in the porcine model (R2 > 0.98, P < 0.0001). Iodine leak around the ETT cuff, in the porcine model, occurred only when P(CO2) levels were >2 mm Hg. In the surgery patients, the mean ETT cuff pressure determined clinically by the anesthesiologist was significantly higher than the optimal cuff pressure assessed by P(CO2) (25.2 +/- 3.6 versus 18.2 +/- 7.8 mm Hg, respectively; P < 0.001). According to these findings, optimal ETT cuff filling pressure can be identified by monitoring P(CO2) at the nares or the oropharynx.

IMPLICATIONS

A new, objective, noninvasive method for optimizing endotracheal tube cuff filling based on monitoring carbon dioxide levels in the upper airways can be used to identify the minimal cuff pressure necessary to eliminate leak and prevent aspiration.

Intracuff pressures of endotracheal tubes in the management of airway emergencies: the need for pressure monitoring

STUDY OBJECTIVE

Excessive pressure exerted on the tracheal mucosa is an avoidable factor implicated as a cause of damage after intubation of the trachea with cuffed tubes. Many patients are intubated in the out-of-hospital setting by emergency medical teams. The time spent in the out-of-hospital setting could very well be long enough for tracheal mucosal damage to occur if cuff pressure is not controlled. The objective of this study is to assess the incidence of intracuff excessive pressure in the out-of-hospital setting.

METHODS

We performed an observational prospective study. Every patient who required tracheal intubation was included in the study, regardless of indication. When the patient was stabilized, the cuff was connected to a manometer, and pressure was systematically recorded. Corrections to inflation were performed if necessary to achieve a cuff pressure of 14 to 27 cm H2O.

RESULTS

One hundred seven patients were included. Eighty-five were out-of-hospital patients and 22 were transfers between 2 hospitals who had been previously intubated when the mobile intensive care unit team arrived. The first recorded cuff pressures were greater than 27 cm H2O among 79% of patients (85/107), with a mean pressure of 56 cm H2O (SD+/-34 cm H2O) in out-of-hospital patients and 69 cm H2O (SD+/-37 cm H2O) for transferred patients. Pressure correction was made in 72% of patients (77/107). There were corrections in 69% (59/85) of out-of-hospital patients and 82% (18/22) of transferred patients.

CONCLUSION

This study revealed that the majority of cuff pressures exceeded safe pressure and required correction. Frequent measurement and adjustment of cuff pressure has been recommended, but this method requires a specific manometer.

[Cuff pressure monitoring and regulation in adults]

OBJECTIVES

In adults the use of cuffed endotracheal tubes is the standard technique. Nitrous oxide increases the cuff pressure secondary to diffusion through the cuff membrane. The aim of the study was to verify a newly designed cuff pressure regulating device and comparison of postoperative complications.

METHODS

In a prospective, randomized, open trial the cuff pressure and the incidence of postoperative complications (e.g., hoarseness, coughing and pain while swallowing) were measured using the newly designed automatic pressure monitoring and regulating device Cuff Pressure Control (Tracoe) and a conventional handheld manometer. A total of 40 patients were assigned to the automatic group with a goal of 25.5 cmH(2)O and 40 patients to the conventional group where the pressures were kept between 20 cmH(2)0 and 40 cmH(2)0 with intermittent measurements and manual pressure release.

RESULTS

The automatic device reliably maintained the pressure at the chosen constant level within +/-2 cmH(2)O. In the control group increases in cuff pressure to 40 cmH(2)O were common. The incidence of postoperative complications in both groups was not significantly different.

CONCLUSIONS

In conclusion our data demonstrate that the automatic cuff pressure and regulation device was useful and reliable in an adult population of intubated patients in the studied pressure range.

Long-term complications of artificial airways

In summary, long-term complications of artificial airways are rare but important sequelae of artificial airways. Many of the potential long-term complications of translaryngeal intubation and tracheotomy are similar and overlapping. Although most patients who undergo these procedures tend to tolerate them without difficulties, significant morbidity and mortality may occur. Identifying the exact cause of the complication may not be possible at times, due to the multiple risk factors involved in the pathogenesis. It is hoped that understanding these potential complications will lead to a more vigilant preventive measures during the institution of long-term artificial airways and a judicious early search for the underlying pathology when a complication is suspected.

Regular tracheostomy tube changes to prevent formation of granulation tissue

OBJECTIVES/HYPOTHESIS

Tracheostomy is a commonly performed operative procedure that has been described since 2000 B.C. The early indications for tracheostomy were for upper airway obstruction, usually occurring in young people as a result of an infectious process. Recently, tracheostomies are more commonly performed in the critically ill patient to assist in long-term ventilatory support. Granulation tissue at the stoma and the trachea has been described as a late complication resulting in bleeding, drainage, and difficulty with maintaining mechanical ventilatory support.

STUDY DESIGN

The present report is of an observational study of a newly implemented policy that required regular changing of tracheostomy tubes. Comparable groups of patients were compared before and after this procedural change to document complications. Data collection consisted of chart reviews of all admissions for 1 year before the policy change and the subsequent 2 years. Complication rates were compared using standard statistical techniques.

METHODS

A policy change was instituted that required all tracheostomy tubes to be changed every 2 weeks in conjunction with a detailed evaluation of the tracheostomy stoma. Charts were reviewed the year before the change in policy and in the subsequent 2 years to determine the incidence of granulation tissue requiring operative intervention.

RESULTS

The number of patients requiring surgical intervention secondary to granulation tissue showed a statistically significant decrease (P =.02). A review of policies and procedures from the six largest hospitals in southeastern Michigan had no recommendations for routine tracheostomy tube changes.

CONCLUSIONS

A policy requiring a routine change of tracheostomy tubes results in fewer complications from granulation tissue. Tracheostomy tube changes to prevent granulation tissue and its complications.

Measurement of tracheal tube cuff pressure in critical care

We conducted an observational study to measure tracheal tube cuff pressures in the critical care environment, where prolonged intubation is common. Thirty-two patients were studied. Sixty-two per cent of all tracheal cuffs had intracuff pressures above the recommended value. We also conducted a telephone survey of 24 intensive care units within the Northern and Yorkshire Region, which showed that 75% of the intensive care units never checked tracheal tube cuff pressures. Critically ill patients are particularly vulnerable to tracheal injury due to prolonged intubation. We suggest that cuff pressures should be measured regularly.

Bronchial cuff pressure change caused by left-sided double-lumen endobronchial tube displacement

PURPOSE

The bronchial cuff pressures (BCPs) of left-sided double-lumen endobronchial tubes (DLTs) manufactured by Rüsch and Mallinckrodt were measured in 80 patients when the tubes were withdrawn to compare the effect of tube design on BCP change.

METHODS

During general anesthesia with muscle relaxation, the cephalad surface of the endobronchial cuff was positioned either 2.5 cm distal to the carina (Rüsch Group R-I; n = 20 and Mallinckrodt Group B-I; n = 20) or just below the carina (Rüsch Group R- II; n = 20 and Mallinckrodt Group B- II; n = 20) and the cuff was inflated to 35 cm H2O. The tube was then withdrawn in 0.5-cm steps until the cuff was 2.0 cm proximal to the carina, the position just before the capnogram or pressure-volume loop of tracheal lumen changed. The BCP at each step was measured. The rate of decrease in BCP was defined as the decrease of BCP divided by the length of displacement of DLT.

RESULTS

The rates of decrease from the +2.5 cm position to the end point in Group B-I (7.7+/-0.8 cm H2O x cm(-1) and those from the most proximal acceptable position to the end point in Group B-II (19.5+/-4.8 cm H2O x cm(-1) were greater than those in Group R-I (6.9+/-0.9 cm H2O x cm(-1) (P<0.01) and in Group R-II (12.4+/-3.1 cm H2O x cm(-1)) (P<0.01), respectively.

CONCLUSION

The BCP decreased in both of the Mallinckrodt and Rüsch DLTs, and the rates of decrease of the former were greater than those of the latter.

Mucosal pressure and oropharyngeal leak pressure with the ProSeal versus laryngeal mask airway in anaesthetized paralysed patients

The ProSeal laryngeal mask airway (PLMA) is a new laryngeal mask device with a larger, wedge-shaped cuff and a drainage tube. We tested the hypothesis that directly measured mucosal pressure and oropharyngeal leak pressure (OLP) are higher for the PLMA compared with the laryngeal mask airway (LMA). We also assess the mechanism of seal, and the reliability of cuff volume, in vivo intracuff pressure and calculated mucosal pressure (in vivo minus in vitro intracuff pressure) to predict directly measured mucosal pressure. Thirty-two anaesthetized, paralysed adult patients were randomly allocated to receive either a size 4 LMA or PLMA. Microchip sensors were attached at locations corresponding to: (a) base of tongue; (b) distal oropharynx; (c) hypopharynx; (d) lateral pharynx; (e) posterior pharynx; and (f) pyriform fossa. In vitro and in vivo intracuff pressures, OLP and directly measured mucosal pressure were documented at zero volume and after each 10 ml up to 40 ml. Directly measured mucosal pressure was similar between devices for a given cuff volume, but was lower for the PLMA for a given OLP. Directly measured mucosal pressure was highest in the distal oropharynx for both devices, but rarely (< 5%) exceeded 35 cm H2O. OLP was higher for the PLMA at all cuff volumes. Directly measured mucosal pressure was usually lower than OLP for both devices, and there was a positive correlation between directly measured mucosal pressure and OLP. Cuff volume, in vivo intracuff pressure and calculated mucosal pressure were poor to moderate predictors of directly measured mucosal pressure for the LMA and PLMA. We conclude that the PLMA forms a better seal than the LMA without an increase in directly measured mucosal pressure.

Surgical airway management in the intensive care unit

Despite having been a known surgical procedure for over 5000 years, the specifics of how, when, and why to perform a surgical airway are still debated. With new procedures, equipment, and techniques, operative airway management is becoming more complex. New methods of surgical airway management have to be evaluated against the gold standard, which will always be the open tracheostomy performed in the operating room. Unlike Dr. Jackson in 1909, surgeons today have to evaluate these new procedures not only by their efficacy but also by their cost effectiveness.