Correlations between controlled endotracheal tube cuff pressure and postprocedural complications: a multicenter study

Comparison of the endotracheal tube cuff pressure between a tapered- versus a cylindrical-shaped cuff after changing from the supine to the lateral flank position

PURPOSE

Positional change can displace an endotracheal tube (ETT) and change the ETT cuff pressure in a tracheally intubated patient. Endotracheal tubes with different cuff shapes may lead to different cuff pressures after positional change. We hypothesized that the intracuff pressure in the TaperGuard™ ETT with a tapered-shaped cuff would be higher than that in the conventional ETT with a cylindrical-shaped cuff after a change from the supine to the lateral flank position.

METHODS

Fifty-eight patients scheduled for open urological procedures in the lateral flank position were randomly allocated to receive either a TaperGuard ETT (group T) or conventional ETT (group C). The ETT cuff pressure was initially set at 20 cm H2O in the supine position and was measured after the change to the lateral flank position. The distance from the ETT tip to the carina was measured in both the supine and the lateral flank positions.

RESULTS

Two patients, one from each group, were excluded from the data analysis. The mean (SD) ETT cuff pressure was significantly higher in group T (n = 28) than in group C (n = 28) after the change in position [31 (7) cm H2O vs 25 (4) cm H2O, respectively; mean difference, 6 cm; 95% confidence intervals [CI], 3 to 9; P < 0.001]. The mean (SD) proximal migration of the ETT tip was comparable between the two groups [8 (18) mm vs 4 (14) mm, respectively; P = 0.367].

CONCLUSIONS

After the change from the supine to the lateral flank position, the ETT cuff pressure was significantly higher in the TaperGuard ETT than in the conventional ETT, although the extent of cephalad displacement of the ETT was comparable between the two groups. This trial was registered at Clinicaltrials.gov: NCT02165319.

Tracheal cuff pressure monitoring in the ICU: a literature review and survey of current practice in Queensland

The application of tracheal cuff pressure monitoring is likely to vary between institutions. The aim of this study was therefore to review current evidence concerning this intervention in the intensive care unit (ICU) and to appraise regional practice by performing a state-wide survey. Publications for review were identified through searches of PubMed, EMBASE and Cochrane (1977 to 2014). All studies in English relevant to critical care and with complete data were included. Survey questions were developed by small-group consensus. Public and private ICUs across Queensland were contacted, with responses obtained from a representative member of the medical or nursing staff. Existing literature suggests significant variability in tracheal cuff pressure monitoring in the ICU, particularly in the applied technique, frequency of assessment and optimal intra-cuff pressures. Twenty-nine respondents completed the survey, representing 80.5% (29/36) of ICUs in Queensland. Twenty-eight out of twenty-nine respondents reported routinely monitoring tracheal cuff function, primarily employing cuff pressure measurement (26/28). Target cuff pressures varied, with 3/26 respondents aiming for 10 to 20 cmH2O, 10/26 for 21 to 25 cmH2O, and 13/26 for 26 to 30 cmH2O. Fifteen out of twenty-nine reported they had no current guideline or protocol for tracheal cuff management and only 16/29 indicated there was a dedicated area in the clinical record for reporting cuff intervention. Our results indicate that many ICUs across Queensland routinely measure tracheal cuff function, with most utilising pressure monitoring devices. Consistent with existing literature, the optimum cuff pressure remains uncertain. Most, however, considered that this should be a routine part of ICU care.

[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%).

Tracheal tube cuff inflation guided by pressure volume loop closure associated with lower postoperative cuff-related complications: Prospective, randomized clinical trial

Background:

The main function of an endotracheal tube (ETT) cuff is to prevent aspiration. High cuff pressure is usually associated with postoperative complications. We tried to compare cuff inflation guided by pressure volume loop closure (PV-L) with those by just to seal technique (JS) and assess the postoperative incidence of sore throat, cough and hoarseness.

Materials and Methods:

In a prospective, randomized clinical trial, 100 patients’ tracheas were intubated. In the first group (n = 50), ETT cuff inflation was guided by PV-L, while in the second group (n. = 50) the ETT cuff was inflated using the JS technique. Intracuff pressures and volumes were measured. The incidence of postoperative cuff-related complications was reported.

Results:

Demographic data and durations of intubation were comparable between the groups. The use of PV-L was associated with a lesser amount of intracuff air [4.05 (3.7-4.5) vs 5 (4.8-5.5), P < 0.001] and lower cuff pressure than those in the JS group [18.25 (18-19) vs 33 (32-35), P ≤ 0.001]. The incidence of postextubation cuff-related complications was significantly less frequent among the PV-L group patients as compared with the JS group patients (P ≤ 0.009), except for hoarseness of voice, which was less frequent among the PV-L group, but not statistically significant (P ≤ 0.065). Multiple regression models for prediction of intra-cuff pressure after intubation and before extubation revealed a statistically significant association with the technique used for cuff inflation (P < 0.0001).

Conclusions:

The study confirms that PV-L-guided ETT cuff inflation is an effective way to seal the airway and associates with a lower ETT cuff pressure and lower incidence of cuff-related complications.

Changes in endotracheal tube cuff pressure during laparoscopic surgery in head-up or head-down position

BACKGROUND

The abdominal insufflation and surgical positioning in the laparoscopic surgery have been reported to result in an increase of airway pressure. However, associated effects on changes of endotracheal tube cuff pressure are not well established.

METHODS

70 patients undergoing elective laparoscopic colorectal tumor resection (head-down position, n = 38) and laparoscopic cholecystecomy (head-up position, n = 32) were enrolled and were compared to 15 patients undergoing elective open abdominal surgery. Changes of cuff and airway pressures before and after abdominal insufflation in supine position and after head-down or head-up positioning were analysed and compared.

RESULTS

There was no significant cuff and airway pressure changes during the first fifteen minutes in open abdominal surgery. After insufflation, the cuff pressure increased from 26 ± 3 to 32 ± 6 and 27 ± 3 to 33 ± 5 cmH2O in patients receiving laparoscopic cholecystecomy and laparoscopic colorectal tumor resection respectively (both p < 0.001). The head-down tilt further increased cuff pressure from 33 ± 5 to 35 ± 5 cmH2O (p < 0.001). There six patients undergoing colorectal tumor resection (18.8%) and eight patients undergoing cholecystecomy (21.1%) had a total increase of cuff pressure more than 10 cm H2O (18.8%). There was no significant correlation between increase of cuff pressure and either the patient's body mass index or the common range of intra-abdominal pressure (10-15 mmHg) used in laparoscopic surgery.

CONCLUSIONS

An increase of endotracheal tube cuff pressure may occur during laparoscopic surgery especially in the head-down position.

Continuous control of tracheal cuff pressure for the prevention of ventilator-associated pneumonia in critically ill patients: where is the evidence?

PURPOSE OF REVIEW

Ventilator-associated pneumonia (VAP) is a major cause of death, morbidity and costs in ICUs. Several evidence-based clinical interventions have been increasingly described for its prevention. However, continuous control of tracheal cuff pressure (Pcuff) is rarely mentioned in the latest clinical guidelines. This review focuses on the available data about the management of Pcuff in the ICU, including discontinuous and continuous control, and its impact on the prevention of VAP.

RECENT FINDINGS

Current discontinuous monitoring and adjustment of Pcuff, even well performed, is inaccurate in maintaining Pcuff in the target range. Underinflation (Pcuff<20 cmH2O) of tracheal cuff is an independent risk factor for VAP through microaspiration of contaminated subglottic secretions into the lower respiratory tract. Two main types of devices, electronic and pneumatic, have been developed for the continuous control of Pcuff. Both have shown effectiveness in maintaining Pcuff in recommended range in ICU patients, but only the pneumatic device has provided a reduction in microaspiration and VAP incidence.

SUMMARY

Continuous controllers of Pcuff represent effective, easy to use and timesaving devices in today's busy ICU environment. However, further studies are required to determine the impact of continuous control of Pcuff on VAP incidence, patient outcomes, antimicrobial consumption and to compare pneumatic and electronic devices, before generalizing their use in routine practice.

Creation of an in vitro biomechanical model of the trachea using rapid prototyping

Previous in vitro models of the airways are either rigid or, if flexible, have not matched in vivo compliance characteristics. Rapid prototyping provides a quickly evolving approach that can be used to directly produce in vitro airway models using either rigid or flexible polymers. The objective of this study was to use rapid prototyping to directly produce a flexible hollow model that matches the biomechanical compliance of the trachea. The airway model consisted of a previously developed characteristic mouth-throat region, the trachea, and a portion of the main bronchi. Compliance of the tracheal region was known from a previous in vivo imaging study that reported cross-sectional areas over a range of internal pressures. The compliance of the tracheal region was matched to the in vivo data for a specific flexible resin by iteratively selecting the thicknesses and other dimensions of tracheal wall components. Seven iterative models were produced and illustrated highly non-linear expansion consisting of initial rapid size increase, a transition region, and continued slower size increase as pressure was increased. Thickness of the esophageal interface membrane and initial trachea indention were identified as key parameters with the final model correctly predicting all phases of expansion within a value of 5% of the in vivo data. Applications of the current biomechanical model are related to endotracheal intubation and include determination of effective mucus suctioning and evaluation of cuff sealing with respect to gases and secretions.

Optimal care and design of the tracheal cuff in the critically ill patient

Despite the increasing use of non-invasive ventilation and high-flow nasal-oxygen therapy, intubation is still performed in a large proportion of critically ill patients. The aim of this narrative review is to discuss recent data on long-term intubation-related complications, such as microaspiration, and tracheal ischemic lesions. These complications are common in critically ill patients, and are associated with substantial morbidity and mortality. Recent data suggest beneficial effects of tapered cuffed tracheal tubes in reducing aspiration. However, clinical data are needed in critically ill patients to confirm this hypothesis. Polyurethane-cuffed tracheal tubes and continuous control of cuff pressure could be beneficial in preventing microaspiration and ventilator-associated pneumonia (VAP). However, large multicenter studies are needed before recommending their routine use. Cuff pressure should be maintained between 20 and 30 cmH₂O to prevent intubation-related complications. Tracheal ischemia could be prevented by manual or continuous control of cuff pressure.

Hoarseness after thyroidectomy: blame the endocrine surgeon alone?

OBJECTIVE

Hoarseness is a postoperative complication of thyroidectomy, mostly due to damage to the recurrent laryngeal nerve (RLN). Hoarseness may also be brought about via vocal cord dysfunction (VCD) due to injury of the vocal cords from manipulations during anesthesia, as well as from psychogenic disorders and respiratory and upper-GI related infections. We reviewed the literature aiming to explore these potential surgical and non-surgical causes of hoarseness beyond thyroidectomy and the role of the endocrine surgeon. Is he/she alone to blame?

METHODS/MATERIAL

The MEDLINE/PubMed database was searched for publications with the medical subject heading "hoarseness" and keywords "thyroidectomy", "RLN", "VCD" or "intubation". We restricted our search till up to May 2013.

RESULTS

In our final review we included 80 articles and abstracts that were accessible and available in English. We demonstrated the incidence of hoarseness stemming from surgical and non-surgical causes and also highlighted the role of intubation as a potential cause of injury-related VCD.

CONCLUSIONS

Hoarseness is a relatively common complication of thyroidectomy, which can be attributed to many factors including surgeon's error or injuries during intubation as well as to other non-surgical causes. However, compared to procedures such as cervical spine surgery, mediastinal surgery, esophagectomy and endarterectomy, thyroidectomy would seem to be a procedure with a relatively low rate of recurrent laryngeal nerve palsies (RLNPs). It is often difficult to determine whether the degree of hoarseness after thyroidectomy should be attributed only the surgical procedure itself or to other causes, for example intubation and extubation maneuvers. The differential diagnosis of postoperative hoarseness requires the use of specific tools, such as stroboscopy and intra- and extralaryngeal electromyography, while methods like acoustic voice analysis, with estimation of maximum phonation time and phonation frequency range, can distinguish between objective and subjective deterioration in the voice. The importance of medical history should be also emphasized.

Dexamethasone for preventing postoperative sore throat: a meta-analysis of randomized controlled trials

BACKGROUND

Postoperative sore throat (POST) is a common complication following tracheal intubation. The effectiveness of prophylactic dexamethasone on POST needs further elucidation.

AIMS

To evaluate the effectiveness and safety of intravenous dexamethasone for the prevention of POST in patients undergoing endotracheal intubation.

METHODS

Studies were identified by literature searches of PubMed, Embase, and the Cochrane database. Systematic review was performed by two independent investigators.

RESULTS

We summarized 7 RCTs including 727 participants. Intravenous dexamethasone significantly reduced the risk of POST at 24 h [pooled risk ratio (RR) = 0.676; 95 % confidence interval (CI) 0.494-0.925; P = 0.014; heterogeneity test, I (2) = 45.8 %], as well as alleviating its severity [standardized mean difference (SMD) = -1.15; 95 % CI -1.86 to -0.45; P = 0.002; heterogeneity test, I (2) = 91.7 %]. Further sub-group analysis indicated a significant relationship between dexamethasone and reduced risk of POST when its dose was over 0.1 mg/kg. No severe adverse effects were reported.

CONCLUSIONS

Our results suggest that intravenous dexamethasone reduces the risk and severity of POST from intubation at 24 h. The effective dosage of dexamethasone for preventing the risk of POST appeared to be over 0.1 mg/kg.

Prospective observational study on tracheal tube cuff pressures in emergency patients--is neglecting the problem the problem?

Background

Inappropriately cuffed tracheal tubes can lead to inadequate ventilation or silent aspiration, or to serious tracheal damage. Cuff pressures are of particular importance during aeromedical transport as they increase due to decreased atmospheric pressure at flight level. We hypothesised, that cuff pressures are frequently too high in emergency and critically ill patients but are dependent on providers’ professional background.

Methods

Tracheal cuff pressures in patients intubated before arrival of a helicopter-based rescue team were prospectively recorded during a 12-month period. Information about the method used for initial cuff pressure assessment, profession of provider and time since intubation was collected by interview during patient handover. Indications for helicopter missions were either Intensive Care Unit (ICU) transports or emergency transfers. ICU transports were between ICUs of two hospitals. Emergency transfers were either evacuation from the scene or transfer from an emergency department to a higher facility.

Results

This study included 101 patients scheduled for aeromedical transport. Median cuff pressure measured at handover was 45 (25.0/80.0) cmH₂O; range, 8-120 cmH₂O. There was no difference between patient characteristics and tracheal tube-size or whether anaesthesia personnel or non-anaesthesia personnel inflated the cuff (30 (24.8/70.0) cmH₂O vs. 50 (28.0/90.0) cmH₂O); p = 0.113.

With regard to mission type (63 patients underwent an emergency transfer, 38 patients an ICU transport), median cuff pressure was different: 58 (30.0/100.0) cmH₂O in emergency transfers vs. 30 (20.0/45.8) cmH₂O in inter-ICU transports; p < 0.001. For cuff pressure assessment by the intubating team, a manometer had been applied in 2 of 59 emergency transfers and in 20 of 34 inter-ICU transports (method was unknown for 4 cases each). If a manometer was used, median cuff pressure was 27 (20.0/30.0) cmH₂O, if not 70 (47.3/102.8) cmH₂O; p < 0.001.

Conclusions

Cuff pressures in the pre-hospital setting and in intensive care units are often too high. Interestingly, there is no significant difference between non-anaesthesia and anaesthesia personnel. Acceptable cuff pressures are best achieved when a cuff pressure manometer has been used. This method seems to be the only feasible one and is recommended for general use.

The size of endotracheal tube and sore throat after surgery: a systematic review and meta-analysis

BACKGROUND

Recent studies showed that sore throat following endotracheal intubation was a common problem following surgery. The objective of this systematic review and meta-analysis of published randomized controlled trials (RCTs) or cohort studies was to estimate whether the size of endotracheal tube (ETT) affects the incidence of postoperative sore throat (POST) after general anesthesia.

METHODS

The following databases were searched electronically: PubMed (updated to Dec 2012), EMBASE (updated to 15 Dec 2012), Google scholar, World Health Organization International Clinical Trials Registry Platform (Jul 2011), Chinese BioMedical Literature Database (1978 to Jul 2011), and China National Knowledge Infrastructure (1994 to Jul 2011). Studies comparing the size of endotracheal tube for elective surgery were included.

RESULTS

Three trials with a total of 509 female patients were included in the current analysis. The size of ETT used were 6.0 mm and 7.0 mm. Pooled studies from these trials showed that the smaller size of ETT (6.0 mm) significantly decreased the incidence of POST in post-anesthesia care unit (PACU) (RR = 0.56, 95% CI 0.42-0.75, P<0.01) and at 24 h after surgery (RR = 0.69, 95% CI 0.48-0.99, P<0.05). A smaller size of ETT (6.0 mm) was associated with a lower incidence of PH in PACU (RR = 0.69, 95% CI 0.55-0.87, P<0.01), but did not affect the incidence of PH at 24 h after surgery (RR = 0.73, 95% CI 0.46-1.15, P>0.05).

CONCLUSION

Our meta-analysis suggests that patients under general anesthesia with a smaller size of ETT (6.0 mm) were associated with a lower incidence of POST in female patients. More studies with adequate numbers of patients were warranted to evaluate other size of ETT on the incidence of PH and POST after general surgery among different populations.

Maintaining endotracheal tube cuff pressure at 20 mm Hg to prevent dysphagia after anterior cervical spine surgery; protocol of a double-blind randomised controlled trial

BACKGROUND

In anterior cervical spine surgery a retractor is obligatory to approach the spine. Previous studies showed an increase of endotracheal tube cuff pressure after placement of a retractor. It is known that high endotracheal tube cuff pressure increases the incidence of postoperative dysphagia, hoarseness, and sore throat. However, until now no evidence supports the fact whether adjusting the endotracheal tube cuff pressure during anterior cervical spine surgery will prevent this comorbidity. We present the design of a randomized controlled trial to determine whether adjusting endotracheal tube cuff pressure after placement of a retractor during anterior cervical spine surgery will prevent postoperative dysphagia.

METHODS/DESIGN

177 patients (aged 18-90 years) scheduled for anterior cervical spine surgery on 1 or more levels will be included. After intubation, endotracheal tube cuff pressure is manually inflated to 20 mm Hg in all patients. Patients will be randomized into two groups. In the control group endotracheal tube cuff pressure is not adjusted after retractor placement. In the intervention group endotracheal tube cuff pressure after retractor placement is maintained at 20 mm Hg and air is withdrawn when cuff pressure exceeds 20 mm Hg. Endotracheal tube cuff pressure is measured after intubation, before and after placement and removal of the retractor. Again air is inflated if cuff pressure sets below 20 mmHg after removal of the retractor. The primary outcome measure is postoperative dysphagia. Other outcome measures are postoperative hoarseness, postoperative sore throat, degree of dysphagia, length of hospital stay, and pneumonia. The study is a single centre double blind randomized trial in which patients and research nurses will be kept blinded for the allocated treatment during the follow-up period of 2 months.

DISCUSSION

Postoperative dysphagia occurs frequently after anterior cervical spine surgery. This may be related to high endotracheal tube cuff pressure. Whether adaptation and maintaining the pressure after placement of the retractor will decrease the incidence of dysphagia, has to be determined by this trial.

TRIAL REGISTRATION

Netherlands Trial Register (NTR) 3542: http://www.trialregister.nl.

Intubation-related tracheal ischemic lesions: incidence, risk factors, and outcome

PURPOSE

To determine incidence, risk factors and outcome of tracheal ischemic lesions related to intubation.

METHODS

Planned post hoc analysis using patients from a previous randomized controlled study. Fiberoptic tracheoscopy was performed during the 24 h following extubation. In patients with >2 ischemic lesions, ulcer or tracheal rupture, fiberoptic tracheoscopy was repeated 2 weeks after the last extubation. Tracheal ischemic lesions were predefined based on a quantitative score.

RESULTS

Ninety-six adult patients were included in this study. Eighty (83 %) patients had at least one tracheal ischemic lesion. Thirty-seven (38 %) patients had a tracheal ischemia score > median score (5; IQ 1, 7). The most common tracheal ischemic lesion was ischemia (68 %), followed by hyperemia (54 %), ulcer (10 %), and tracheal rupture (1 %). Univariate analysis identified duration of neuromuscular-blocking agent use, overinflation of tracheal cuff (>30 cmH2O), percentage of P cuff determination >30 cmH2O, duration of assist-control ventilation, and plateau pressure as risk factors for having a tracheal ischemia score >5. Duration of assist-control mechanical ventilation was the only factor independently associated with tracheal ischemia score >5 [OR (95 % CI) 1.10 per hour (1.02-1.20)]. A fiberoptic tracheoscopy was performed 2 weeks after extubation in 22 patients. This examination was normal in all patients, except the one with tracheal rupture who had marked improvement.

CONCLUSION

Tracheal ischemic lesions are common in intubated, critically ill patients. Duration of assist-control mechanical ventilation through a tracheal tube is the only independent risk factor. These lesions healed in the majority of patients 2 weeks after extubation.

Endotracheal tube cuff pressure before, during, and after fixed-wing air medical retrieval

Abstract Background. Increased endotracheal tube (ETT) cuff pressure is associated with compromised tracheal mucosal perfusion and injuries. No published data are available for Australia on pressures in the fixed-wing air medical retrieval setting. Objective. After introduction of a cuff pressure manometer (Mallinckrodt, Hennef, Germany) at the Royal Flying Doctor Service (RFDS) Base in Dubbo, New South Wales (NSW), Australia, we assessed the prevalence of increased cuff pressures before, during, and after air medical retrieval. Methods. This was a retrospective audit in 35 ventilated patients during fixed-wing retrievals by the RFDS in NSW, Australia. Explicit chart review of ventilated patients was performed for cuff pressures and changes during medical retrievals with pressurized aircrafts. Pearson correlation was calculated to determine the relation of ascent and ETT cuff pressure change from ground to flight level. Results. The mean (± standard deviation) of the first ETT cuff pressure measurement on the ground was 44 ± 20 cmH2O. Prior to retrieval in 11 patients, the ETT cuff pressure was >30 cmH2O and in 11 patients >50 cmH2O. After ascent to cruising altitude, the cuff pressure was >30 cmH2O in 22 patients and >50 cmH2O in eight patients. The cuff pressure was reduced 1) in 72% of cases prior to take off and 2) in 85% of cases during flight, and 3) after landing, the cuff pressure increased in 85% of cases. The correlation between ascent in cabin altitude and ETT cuff pressure was r = 0.3901, p = 0.0205. Conclusions. The high prevalence of excessive cuff pressures during air medical retrieval can be avoided by the use of cuff pressure manometers. Key words: cuff pressure; air medical retrieval; prehospital.

A smaller endotracheal tube combined with intravenous lidocaine decreases post-operative sore throat - a randomized controlled trial

BACKGROUND

Post-operative sore throat (POST) has increasingly been a common clinical complication particularly in thyroid surgery. We conducted a trial to evaluate the effect of non-pharmacological [smaller-sized endotracheal tube (ETT)] combined with pharmacological intervention [lidocaine intravenous (i.v.)] on POST in women undergoing thyroid surgery.

METHODS

Two hundred and forty patients scheduled for thyroid surgery were randomly divided into four groups: Group A, ETT size 7.0 with saline; Group B, ETT size 6.0 with saline; Group C, ETT size 7.0 with lidocaine; Group D, ETT size 6.0 with lidocaine. Patients in Groups C and D received i.v. 1.5 mg/kg lidocaine that was filled in syringe up to 10 ml 5 min before induction of anaesthesia; whereas patients in Groups A and B received an equal volume of saline. The incidence and severity of POST were evaluated at 1, 6 and 24 h after tracheal extubation.

RESULTS

The highest incidence of POST occurred at 6 h after extubation in all groups. The incidence of POST was significantly lower in Group D compared with Groups A (23% vs. 62%, P < 0.01), B (23% vs. 42%, P = 0.03) and C (23% vs. 43%, P = 0.02) at 6 h after extubation. Group D had significantly decreased severity of POST compared with Groups A, B and C 6 and 24 h after extubation (P < 0.05).

CONCLUSION

Use of smaller-sized ETT combined with i.v. lidocaine decreases the incidence and severity of POST in women undergoing thyroid surgery.

Efficacy of intravenous dexamethasone to reduce incidence of postoperative sore throat: A prospective randomized controlled trial

BACKGROUND

Sore throat and hoarseness are common complications of endotracheal intubation. It may be very distressing for the patient and may lead to sleep disturbances and unpleasant memories.

MATERIALS AND METHODS

This prospective double-blinded randomized control trial was aimed to determine the efficacy of prophylactic intravenous dexamethasone to reduce the incidence of postoperative sore throat at 1 hour after tracheal extubation. Ninety six patients of either sex aged between 18 to 60 years scheduled for elective surgeries needing general anesthesia with endotracheal intubation, were randomly allocated into two groups A and B. The patients received either intravenous 0.2 mg/kg dexamethasone (group A, n = 48) or normal saline (group B, n = 47) just before induction. Trachea was intubated with appropriate size disposable endotracheal tubes for securing the airway. Follow up for the incidence of sore throat, cough and hoarseness was done at 1, 6 and 24 hours post-extubation.

RESULTS

At 1 hour post-extubation, the incidence of sore throat in the control group was 48.9% compared with 18.8% in the dexamethasone group (P<0.002).

CONCLUSIONS

Prophylactic intravenous dexamethasone in a dose of 0.2 mg/kg can reduce the incidence of postoperative sore throat at 1 hour post-extubation by around 30%, with the efficacy being around 60%.

Prediction of optimal endotracheal tube cuff volume from tracheal diameter and from patient height and age: a prospective cohort trial

PURPOSE

Endotracheal tube intra-cuff pressure should be maintained between 20 and 30 cmH(2)O to prevent damage to the tracheal wall. However, cuff pressure is rarely measured, and clinicians estimate cuff pressure poorly. The goal of the present study was to predict the cuff volume that produces optimal cuff pressure either from tracheal diameter or from patient height and age.

METHODS

In the development phase, initial cuff pressure and cuff volume were measured in 240 patients. Optimal cuff volume, defined as the volume halfway between the volumes required to produce cuff pressures of 20 and 30 cmH(2)O, was determined in each patient. Then, regression equations relating optimal cuff volume to tracheal diameter on chest X-ray, and between optimal cuff volume and a combination of height and age, were calculated. The primary outcome was the proportion of patients in a validation set (n = 104) who achieved a cuff pressure of 20-30 cmH(2)O when cuff volume was selected by each regression formula.

RESULTS

Only 28% of the cuffs were optimally inflated using clinical criteria during the development phase. There was good correlation between optimal cuff volume and tracheal diameter and moderate correlation between optimal cuff volume and both height and age. Predicted cuff volume was more likely to provide optimal cuff pressure when based on tracheal diameter (65% of patients) than when based on both height and age (45% of patients).

CONCLUSIONS

Optimal cuff volume was better estimated from tracheal diameter and patient height and age than from the manual palpation method.

Technical communication: design and in vitro testing of a pressure-sensing syringe for endotracheal tube cuffs

Endotracheal intubation is a frequently performed procedure in the prehospital setting, intensive care unit, and for patients undergoing surgery. The endotracheal tube cuff must be inflated to a pressure that prevents air leaks without compromising tracheal mucosal blood flow. For simultaneous endotracheal tube cuff inflation and measurement, we designed and tested a novel pressure-sensing syringe in vitro. The prototype was developed using a standard 10-mL polycarbonate syringe body that houses a plunger and a silicone rubber bellows, the pressure-sensing element. Bellow feasibility was determined and modeled using finite element analysis. Repeatability testing at each pressure measurement for each bellows (pressure versus deflection) was within an average standard deviation of 0.3 cm to 1.61 cm (1%-5% error). Using an aneroid manometer for comparison, there was excellent linear correlation with a Spearman rank of 0.99 (P < 0.001), up to 30 cm H(2)O.

Endotracheal tube cuff pressure monitoring: a review of the evidence

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

What is new in the prevention of ventilator-associated pneumonia?

PURPOSE OF REVIEW

Ventilator-associated pneumonia (VAP) remains a frequent and severe complication in endotracheally intubated patients. Strict adherence to preventive measures reduces the risk of VAP. The objective of this paper is to review what has come forward in recent years in the nonpharmacological prevention of VAP.

RECENT FINDINGS

It seems advantageous to implement care bundles rather than single prevention measures. A solid basis of knowledge seems necessary to facilitate implementation and maintain a high adherence level. Continuous educational efforts have a beneficial effect on attitude toward VAP. Intermittent subglottic secretions drainage, continuous lateral rotation therapy, and polyurethane cuffed endotracheal tubes decrease the risk of pneumonia. In an in-vitro setting, an endotracheal tube with a taper-shaped cuff appears to better prevent fluid leakage compared to cylindrical polyurethane or polyvinylchloride cuffed tubes. Cuff pressure control by means of an automatic device and multimodality chest physiotherapy need further investigation, as do some aspects of oral hygiene.

SUMMARY

New devices and strategies have been developed to prevent VAP. Some of these are promising but need further study. In addition, more attention is being given to factors that might facilitate the implementation process and the challenge of achieving high adherence rates.