Tracheal Pressure Research Articles

Diaphragm function and weaning from mechanical ventilation: an ultrasound and phrenic nerve stimulation clinical study

BackgroundDiaphragm dysfunction is defined by a value of twitch tracheal pressure in response to magnetic phrenic stimulation (twitch pressure) amounting to less than 11 cmH2O. This study assessed whether this threshold or a lower one would predict accurately weaning failure from mechanical ventilation. Twitch pressure was compared to ultrasound measurement of diaphragm function.MethodsIn patients undergoing a first spontaneous breathing trial, diaphragm function was evaluated by twitch pressure and by diaphragm ultrasound (thickening fraction). Receiver operating characteristics curves were computed to determine the best thresholds predicting failure of spontaneous breathing trial.ResultsSeventy-six patients were evaluated, 48 (63%) succeeded and 28 (37%) failed the spontaneous breathing trial. The optimal thresholds of twitch pressure and thickening fraction to predict failure of the spontaneous breathing trial were, respectively, 7.2 cmH2O and 25.8%, respectively. The receiver operating characteristics curves were 0.80 (95% CI 0.70–0.89) for twitch pressure and 0.82 (95% CI 0.73–0.93) for thickening fraction. Both receiver operating characteristics curves were similar (p = 0.83). A twitch pressure value lower than 11 cmH2O (the traditional cutoff for diaphragm dysfunction) predicted failure of the spontaneous breathing trial with a sensitivity of 89% (95% CI 72–98%) and a specificity of 45% (95% CI 30–60%).ConclusionsFailure of spontaneous breathing trial can be predicted with a lower value of twitch pressure than the value defining diaphragm dysfunction. Twitch pressure and thickening fraction had similar strong performance in the prediction of failure of the spontaneous breathing trial.

Retrosternal Goiter: A couple of classification methods with computed tomograpy findings.

Objectives:The retrosternal goiter (RSG), which can be defined by different classification and its incidence between 2% and 26% of all thyroidectomized patients, is a thyroid gland disease. Our aim was to classify RSG cases with a couple of different ways, which we have detected in computed tomography (CT) imaging of the thorax.Methods:In this retrospective study conducted at Kars Harakani State Hospital Pulmonary Medicine Polyclinic between June 2014 and June 2017 in which 176 patients were included. The age, sex, diagnostic codes, retrosternal extension of the thyroid gland (aortic upper arch, aortic reaching arch and aortic inferior arch), extension type (prevascular, paratracheal retrovascular and retrotracheal), extension amount (mm) (<50% and 50%<) of thyroid gland of the patients were assessed.Results:About 56.25% (n=99) were female and the mean age was 65.9±11.4 years. The most common co-morbid disease in patients with RSG was Chronic Obstructive Pulmonary Disease (COPD) (52.3%). Thirty nine (22.2%) of the patients had associated nodule, 16 (9.1%) had accompanying tracheal pressure and one patient had nodule and tracheal pressure. 27.3% of the patients’ gland’s right lobe and 28.9% of the patients’ left lobe were extended >50% below the thoracic entry. Left thyroid gland’s (90.3%) retrosternal extension and aortic arch spread (91.2%) were more. When classified according to the trachea, the left lobe’s paratracheal and retrovascular extension (50.9%) was more. Extension amounts were similar for both thyroid lobes.Conclusion:In patients who have retrosternal goiter, goiter spread can be defined with multiple classification with thorax CT.

X-ray computed tomography study of the flight-adapted tracheal system in the blowflyCalliphora vicinaanalysing the ventilation mechanism and flow-directing valves

Following the discovery of flight motor-driven unidirectional gas exchange with rising PO2 in the blowfly, X-ray computed tomography (CT) was used to visualize the organization of the tracheal system in the anterior body with emphasis on the arrangement of the pathways for airflow. The fly's head is preferentially supplied by cephalic tracheae originating from the ventral orifice of the mesothoracic spiracle (Sp1). The respiratory airflow during flight is a by-product of cyclic deformations of the thoracic box by the flight muscles. The air sacs below the tergal integument (scutum and scutellum) facilitate the respiratory airflow: the shortening of the thorax turns the scutellum and the wings downward and the scutum upward with a volume increase in the scutal air sacs. The resulting negative pressure sucks air from Sp1 through special tracheae towards the scutal air sacs. The airflow is directed by two valves that open alternately: (1) the hinged filter flaps of the metathoracic spiracles (Sp2) are passively pushed open during the upstroke by the increased tracheal pressure, thereby enabling expiration; (2) a newly described tracheal valve-like septum behind the regular spiracular valve lids of Sp1 opens passively and air is sucked in through Sp1 during the downstroke and prevents expiration by closing during the upstroke. This stabilizes the unidirectional airflow. The tracheal volume of the head, thorax and abdomen and their mass were determined. Despite the different anatomy of birds and flies, the unidirectional airflow reveals a comparable efficiency of the temporal throughput in flies and hummingbirds.

Tracheal cuff pressure change before and after the performance of nursing care.

Verify the changes of endotracheal cuff pressure before and after oral hygiene, head-of-bed elevation at 0º, 30º, and 60º, change in body position, aspiration of the endotracheal tube, and in-bed bathing. The study sample was composed of 88 patients. We performed 3,696 checks from July to September 2014. Pressure values were analyzed in seven nursing care in the morning. Six of them were significantly altered before and after nursing procedure. In the afternoon, five of the health care provided were altered, and in the evening, only two. Most of pressure values were below recommended. There were differences before and after health care provided, showing changes in cuff pressure. In-bed bathing and head-of-bed elevation at 30º were the ones that most altered pressure values in the three working shifts. Therefore, it is necessary to measure cuff pressure at least twice per working shift, preferably after bathing.

Structural and functional evidence for the scaffolding effect of alveolar blood vessels

ABSTRACT A contribution of pulmonary blood distension to alveolar opening was first proposed more than 100 years ago. To investigate the contribution of blood distension to lung mechanics, we studied control mice (normal perfusion), mice after exsanguination (absent perfusion) and mice after varying degrees of parenchymal resection (supra-normal perfusion). On inflation, mean tracheal pressures were higher in the bloodless mouse (4.0 ± 2.5 cm H2O); however, there was minimal difference between conditions on deflation (0.7 ± 0.9 cm H2O). To separate the peripheral and central mechanical effects of blood volume, multi-frequency lung impedance data was fitted to the constant-phase model. The presence or absence of blood had no effect on central airway resistance (p > .05). In contrast, measures of tissue damping (G), tissue elastance (H) and hysteresivity (η) demonstrated a significant increase in bloodless mice relative to control mice (p < .001). After varying amount of surgical resection and associated supra-normal perfusion of the remaining lung, there was an increase in G and H. Although the absolute difference in G and H increased with the amount of parenchymal resection, the proportional contribution of blood was identical in all conditions. The presence of blood in the pulmonary vasculature resulted in a constant 64 ± 5% reduction in tissue damping (G) and a 55 ± 4% reduction in tissue elastance (H). This nearly-constant contribution of blood to lung hysteresivity was only reduced by positive end-expiratory pressure (PEEP). To identify a distinct structural subset of vessels in the lung potentially contributing to these observations, vascular casting and scanning electron microscopy of the lung demonstrated morphologically distinct vascular rings at the alveolar opening. Our results suggest that intravascular blood distension, likely attributable to a subset of vessels in the alveolar entrance ring, contributes a measurable scaffolding effect to the functional recruitment of the peripheral lung.

Correlation of high flow nasal cannula outlet area with gas clearance and pressure in adult upper airway replicas

BackgroundPrimary benefits of high flow nasal cannula therapy include washout of carbon dioxide rich exhaled gas and increased airway pressures during tidal breathing. This work reports on the influence of high flow nasal cannula outlet area on upper airways gas clearance and tracheal pressures using measurements in five realistic adult nose-throat airway replicas. MethodsTwo commercial high flow nasal cannulas and one generic nasal cannula of varying size were compared. 100% oxygen was supplied via cannulas at flow rates ranging from 30 to 90l/min to replicas originally filled with air, and oxygen concentrations at the larynx and trachea were compared over time. Additionally, and separately, replicas were connected to a mechanical lung simulator to simulate tidal breathing while undergoing high flow nasal cannula therapy, with tracheal pressure–time waveforms recorded. FindingsFaster gas clearance corresponded with higher flow rates (P<0.001), and with smaller cannula outlet area (P<0.001). Observed pressures were in approximate agreement with limited available in-vivo data in the literature. Between 0 and 60L/min cannula flow rates, tracheal positive end expiratory pressures increase was greater with the smallest cannula (∆PPEEP=785SD(185) Pa) compared to the largest cannula (∆PPEEP=380SD(120)Pa). Regression analysis indicates that positive end expiratory pressure is proportional to the square of flow velocities exiting the cannula and nares (R2=0.906). InterpretationSince increased pressure and clearance rate have been associated with improved clinical outcomes in previous studies, our results suggest that smaller cannula outlet area may be preferable.

Multicentre randomised controlled trial to investigate the usefulness of continuous pneumatic regulation of tracheal cuff pressure for reducing ventilator-associated pneumonia in mechanically ventilated severe trauma patients: the AGATE study protocol

IntroductionSevere trauma represents the leading cause of mortality worldwide. While 80% of deaths occur within the first 24 hours after trauma, 20% occur later and are mainly due to healthcare-associated...

Tracheoesophageal fistula in a patient with a Left Ventricular Assist Device

SummaryTracheo‐oesophageal fistula (TOF) is a rare complication associated with mechanically ventilated critically ill patients. Predisposing risk factors include high tracheal tube cuff pressure, and the presence of an orogastric tube. We present a case of TOF in a critically ill patient with a left ventricular assist device. Anaesthetists are often called to manage an airway for a displaced tracheal tube or one with a suspected cuff leak. Exchanging a tracheal tube is not without risk. Tracheo‐oesophageal fistula may present in a similar fashion to a leaking or displaced tracheal tube and it is critical to ensure that this diagnosis is not missed.

A design and study of a novel electronic device for cuff-pressure monitoring

To design a novel electronic device for measuring the pressure in the cuff of the artificial airway; and to study the advantage of this device on continuous and intermittent cuff pressure monitoring. (1) a portable electronic device for cuff pressure measurement was invented, which could turn pressure signal into electrical signal through a pressure transducer. Meantime, it was possible to avoid pressure leak from the joint and the inside of the apparatus by modified Luer taper and sophisticated design. If the cuff pressure was out of the normal range, the apparatus could release a sound and light alarm. (2) Six traditional mechanical manometers were used to determine the cuff pressure in 6 tracheal tubes. The cuff pressure was maintain at 30 cmH2O (1 cmH2O = 0.098 kPa) by the manometer first, and repeated every 30 seconds for 4 times. (3) Study of continuous cuff pressure monitoring: We used a random number generator to randomize 6 tracheal tubes, 6 mechanical manometers and 6 our products by number 1-6, which has the same number of a group. Every group was further randomized into two balanced groups, one group used the mechanical manometer first, and the other used our product first. The baseline pressure was 30 cmH2O, measurement was performed every 4 hours for 6 times. When traditional mechanical manometer was used for cuff pressure monitoring, cuff pressure was decreased by an average of 2.9 cmH2O for each measurement (F = 728.2, P = 0.000). In study of continually monitoring, at each monitoring point, the pressure measured by electronic manometer was higher than the mechanical manometer. All the pressures measured by mechanical manometer were dropped below 20 cmH2O at 8th hour, and there was no pressure decrease below 20 cmH2O measured by electronic manometer in 24 hours by contrast. In study of intermittent monitoring, the same result was found. The pressure was dropped significantly with time when measured by mechanical manometer (F = 61.795, P = 0.000), the drops below 20 cmH2O began at 8th hour; but when measured by electronic manometer, all the value stayed unchanged around the baseline in 24 hours (F = 0.511, P = 0.796). Compared with traditional mechanical manometer, cuff pressures monitored by our novel electronic manometer were steadier in both continuous and intermittent monitoring. The device is compact and convenient, and can provide a good solution for continuously monitor of the tracheal cuff pressure.

Comparison of Propofol with Desflurane for Laparoscopic Sleeve Gastrectomy in Morbidly Obese patients: A Prospective Randomized Trial

Background: Laparoscopic sleeve gastrectomy has become one of the most effective treatment options for adults with severe obesity. However, optimal anesthetic management for laparoscopic sleeve gastrectomy has not been described yet. Methods: In this prospective randomized study, we compared the effects of propofol anesthesia (Group 1) with desflurane anesthesia (Group II) in morbid obese patients for laparoscopic sleeve gastrectomy. We compared postoperative recovery and hemodynamic parameters of the patients. We also investigated the changes in tracheal cuff pressure and peak airway pressure of these obese patients during orogastric tube insertion and peritoneal CO2 insufflation. Results: Eye opening and extubation time were longer in the propofol group than in the desflurane group (p 0.05). Six patients in Group I and eight patients in Group II had sore throat (p > 0.05). Eight patients in Group I a...

A canine model of tracheal stenosis induced by cuffed endotracheal intubation

Postintubation tracheal stenosis is a complication of endotracheal intubation. The pathological mechanism and risk factors for endotracheal intubation-induced tracheal stenosis remain not fully understood. We aimed to establish an animal model and to investigate risk factors for postintubation tracheal stenosis. Beagles were intubated with 4 sized tubes (internal diameter 6.5 to 8.0 mm) and cuff pressures of 100 to 200 mmHg for 24 hr. The status of tracheal wall was evaluated by bronchoscopic and histological examinations. The model was successfully established by cuffed endotracheal intubation using an 8.0 mm tube and an intra-cuff pressure of 200 mmHg for 24 hr. When the intra-cuff pressures were kept constant, a larger sized tube would induce a larger tracheal wall pressure and more severe injury to the tracheal wall. The degree of tracheal stenosis ranged from 78% to 91% at 2 weeks postextubation. Histological examination demonstrated submucosal infiltration of inflammatory cells, hyperplasia of granulation tissue and collapse of tracheal cartilage. In summary, a novel animal model of tracheal stenosis was established by cuffed endotracheal intubation, whose histopathological feathers are similar to those of clinical cases of postintubation tracheal stenosis. Excessive cuff pressure and over-sized tube are the risk factors for postintubation tracheal stenosis.

Does Objective Measurement of Tracheal Tube Cuff Pressures Minimise Adverse Effects and Maintain Accurate Cuff Pressures? A Systematic Review and Meta-analysis

Correct inflation pressures of the tracheal cuff are recommended to ensure adequate ventilation and prevent aspiration and adverse events. However there are conflicting views on which measurement to employ. The aim of this review was to examine whether adjustment of cuff pressure guided by objective measurement, compared with subjective measurement or observation of the pressure value alone, was able to prevent patient-related adverse effects and maintain accurate cuff pressures. A search of PubMed, Web of Science, Embase, CINAHL and ScienceDirect was conducted using keywords 'cuff pressure' and 'measure*' and related synonyms. Included studies were randomised or pseudo-randomised controlled trials investigating mechanically ventilated patients both in the intensive care unit and during surgery. Outcomes included adverse effects and the comparison of pressure measurements. Pooled analyses were performed to calculate risk ratios, effect sizes and 95% confidence intervals. Meta-analysis found preliminary evidence that adjustment of cuff pressure guided by objective measurement as compared with subjective measurement or observation of the pressure value alone, has benefit in preventing adverse effects. These included cough at two hours (odds ratio [OR] 0.42, confidence interval [CI] 0.23 to 0.79, P=0.007), hoarseness at 24 hours (OR 0.49, CI 0.31 to 0.76, P <0.002), sore throat (OR 0.73, CI 0.54 to 0.97, P <0.03), lesions of the trachea and incidences of silent aspiration (P=0.001), as well as maintaining accurate cuff pressures (Hedges' g 1.61, CI 2.69 to 0.53, P=0.003). Subjective measurement to guide adjustment or observation of the pressure value alone may lead to patient-related adverse effects and inaccuracies. It is recommended that an objective form of measurement be used.

To Measure Tracheal Tube Cuff Pressure in Traumatic Brain Injury Patients Admitted to Neurocritical Care: An Observational Study

To Measure Tracheal Tube Cuff Pressure in Traumatic Brain Injury Patients Admitted to Neurocritical Care: An Observational Study

Comparison of tracheal tube cuff pressure with two techniques: fixed volume versus pilot balloon palpation.

Introduction: Filling tracheal tube cuff (TTC) after intubation is necessary to provide a safe airway in intubated patients. On the other hand, excessive increase or decrease in the pressure of TTC’s balloon leads into the dangerous complications such as necrosis and/or aspiration. Accordingly, in the present study, we tried to evaluate the most two common fixed volume and pilot balloon palpitation methods to control TTC pressure. Methods: In a prospective cross-sectional study that was carried out in the emergency department of Tabriz Imam Reza hospital upon 194 patients who needed intubation and from April 2015 to June 2016. The patients were randomly allocated into two equal groups. For the first the Pilot Balloon Palpation technique and for the second group 10 cc fixed volume cuff filling technique was assigned. After that, the pressure was checked with manometer and data were analyzed using SPSS software. Results: TTC pressure average in fixed volume group was 44.96±21.77 cmH2O and for palpation group, it was 118.15±22.15 cmH2O. There was a meaningful difference between two groups in terms of cuff inside pressure (P value <0.001) and it was meaningfully lower in fixed volume group than the first one. Conclusion: The present study showed that pilot balloon palpation or fixed volume method was not appropriate methods to assess cuff pressure during intubation and the cuff pressure must be controlled by the manometer.

Coexistence and Impact of Limb Muscle and Diaphragm Weakness at Time of Liberation from Mechanical Ventilation in Medical Intensive Care Unit Patients.

Intensive care unit (ICU)- and mechanical ventilation (MV)-acquired limb muscle and diaphragm dysfunction may both be associated with longer length of stay and worse outcome. Whether they are two aspects of the same entity or have a different prevalence and prognostic impact remains unclear. To quantify the prevalence and coexistence of these two forms of ICU-acquired weakness and their impact on outcome. In patients undergoing a first spontaneous breathing trial after at least 24 hours of MV, diaphragm dysfunction was evaluated using twitch tracheal pressure in response to bilateral anterior magnetic phrenic nerve stimulation (a pressure <11 cm H2O defined dysfunction) and ultrasonography (thickening fraction [TFdi] and excursion). Limb muscle weakness was defined as a Medical Research Council (MRC) score less than 48. Seventy-six patients were assessed at their first spontaneous breathing trial: 63% had diaphragm dysfunction, 34% had limb muscle weakness, and 21% had both. There was a significant but weak correlation between MRC score and twitch pressure (ρ = 0.26; P = 0.03) and TFdi (ρ = 0.28; P = 0.01), respectively. Low twitch pressure (odds ratio, 0.60; 95% confidence interval, 0.45-0.79; P < 0.001) and TFdi (odds ratio, 0.84; 95% confidence interval, 0.76-0.92; P < 0.001) were independently associated with weaning failure, but the MRC score was not. Diaphragm dysfunction was associated with higher ICU and hospital mortality, and limb muscle weakness was associated with longer duration of MV and hospital stay. Diaphragm dysfunction is twice as frequent as limb muscle weakness and has a direct negative impact on weaning outcome. The two types of muscle weakness have only limited overlap.

Study of Duchenne muscular dystrophy long-term survivors aged 40 years and older living in specialized institutions in Japan

The national muscular dystrophy wards database of Japan lists 118 long-term Duchenne muscular dystrophy (DMD) patients who were at least 40 years old as of October 1, 2013. To elucidate the clinical features of DMD patients aged 40 years and older, we obtained gene analysis and muscle biopsy findings, as well as medical condition information. Ninety-four of the registered patients consented to participate, of whom 55 meeting genetic or biochemical criteria confirming DMD were analyzed. The mean age at the time of the study was 43.6 ± 3.0 years, while at the time of independent ambulation loss it was 10.6 ± 1.5 years and at mechanical ventilation introduction it was 24.1 ± 5.5 years. All were receiving continuous ventilation support, 27 with non-invasive positive pressure ventilation and 28 with tracheal intermittent positive pressure ventilation. Thirty-eight were receiving β-blockers or a renin-angiotensin system inhibitor, while 9 were free from those agents. Forty had maintained oral nutrition. The 55 analyzed patients had survived into their 40s by receiving multidisciplinary intervention. Our findings emphasize the need of future studies to investigate disease modifiers and the mechanism of long-term survival. In addition, establishment of a worldwide care standard with focus on quality of life for adult males with DMD is important.

Efficiency of an electronic device in controlling tracheal cuff pressure in critically ill patients: a randomized controlled crossover study.

BackgroundDespite intermittent control of tracheal cuff pressure (P cuff) using a manual manometer, cuff underinflation (<20 cmH2O) and overinflation (>30 cmH2O) frequently occur in intubated critically ill patients, resulting in increased risk of microaspiration and tracheal ischemic lesions. The primary objective of our study was to determine the efficiency of an electronic device in continuously controlling P cuff. The secondary objective was to determine the impact of this device on the occurrence of microaspiration of gastric or oropharyngeal secretions.MethodsEighteen patients requiring mechanical ventilation were included in this prospective randomized controlled crossover study. They randomly received either continuous control of P cuff with Mallinckrodt® device for 24 h, followed by discontinuous control with a manual manometer for 24 h, or the reverse sequence. During the 48 h after randomization, P cuff was continuously recorded, and pepsin and alpha amylase were quantitatively measured in tracheal aspirates. P cuff target was 25 cmH2O.ResultsClinical characteristics were similar during the two study periods, as well as mean airway pressure. Percentage of time spent with cuff overinflation or underinflation was significantly lower during continuous control compared with routine care period [median (IQR) 0.8 (0.1, 2) vs 20.9 (3.1, 40.1), p = 0.0009]. No significant difference was found in pepsin [median (IQR) 230 (151, 300) vs 259 (134, 368), p = 0.95] or in alpha amylase level [median (IQR) 1475 (528, 10,333) vs 2400 (1342, 15,391), p = 0.19] between continuous control and routine care periods, respectively.ConclusionsThe electronic device is efficient in controlling P cuff, compared with routine care using a manometer. Further studies are needed to evaluate the impact of this device on intubation-related complications. Trial registration ClinicalTrials.gov Identifier: NCT01965821

Does objective measurement of tracheal tube cuff pressures minimise adverse effects and maintain accurate cuff pressures? A systematic review and meta-analysis.

Correct inflation pressures of the tracheal cuff are recommended to ensure adequate ventilation and prevent aspiration and adverse events. However there are conflicting views on which measurement to employ. The aim of this review was to examine whether adjustment of cuff pressure guided by objective measurement, compared with subjective measurement or observation of the pressure value alone, was able to prevent patient-related adverse effects and maintain accurate cuff pressures. A search of PubMed, Web of Science, Embase, CINAHL and ScienceDirect was conducted using keywords 'cuff pressure' and 'measure*' and related synonyms. Included studies were randomised or pseudo-randomised controlled trials investigating mechanically ventilated patients both in the intensive care unit and during surgery. Outcomes included adverse effects and the comparison of pressure measurements. Pooled analyses were performed to calculate risk ratios, effect sizes and 95% confidence intervals. Meta-analysis found preliminary evidence that adjustment of cuff pressure guided by objective measurement as compared with subjective measurement or observation of the pressure value alone, has benefit in preventing adverse effects. These included cough at two hours (odds ratio [OR] 0.42, confidence interval [CI] 0.23 to 0.79, P=0.007), hoarseness at 24 hours (OR 0.49, CI 0.31 to 0.76, P <0.002), sore throat (OR 0.73, CI 0.54 to 0.97, P <0.03), lesions of the trachea and incidences of silent aspiration (P=0.001), as well as maintaining accurate cuff pressures (Hedges' g 1.61, CI 2.69 to 0.53, P=0.003). Subjective measurement to guide adjustment or observation of the pressure value alone may lead to patient-related adverse effects and inaccuracies. It is recommended that an objective form of measurement be used.

Patterns of diaphragm function in critically ill patients receiving prolonged mechanical ventilation: a prospective longitudinal study.

BackgroundIn intensive care unit (ICU) patients, diaphragmatic dysfunction (DD) can occur on admission or during the subsequent stay. The respective incidence of these two phenomena has not been previously studied in humans. The study was designed to describe temporal trends in diaphragm function in mechanically ventilated (MV) patients.MethodsAncillary study of a prospective, 6-month, observational cohort study conducted in two ICUs. MV patients were studied within 24 h following intubation (day-1) and every 48–72 h thereafter. Diaphragm function was assessed by twitch tracheal pressure (Ptr,stim) in response to bilateral anterior magnetic phrenic nerve stimulation. Diaphragm dysfunction was defined as Ptr,stim < 11 cmH2O. Patients who received MV for at least 5 days were retained, and the first and the last measures were analysed.ResultsForty-three patients were included. Overall, 79 % of patients developed DD at some point during their ICU stay: 23 (53 %) patients presented DD on initiation of mechanical ventilation, 14 (33 %) of whom had persistent DD, while diaphragm function improved in 9 (21 %). Among the remaining 20 (47 %) patients who did not present DD on initiation of MV, 11 (26 %) developed DD during the ICU stay, while 9 (21 %) did not. Mortality was higher in patients with DD either on initiation of mechanical ventilation or during the subsequent ICU stay than in those who never developed DD (35 vs. 0 %, p = 0.04). Duration of MV was higher in patients with DD on initiation of MV that subsequently persisted than in patients who never exhibited diaphragm dysfunction (18 vs. 5 days, p = 0.04). Factors associated with a change in Ptr,stim were: age [linear coefficient regression (Coeff.) −0.097, standard error (SD) 0.047, p = 0.046], PaO2/FiO2 ratio (Coeff. 0.014, SD 0.006, p = 0.0211) and the proportion of the time under MV with sedation (per 10 %, Coeff. −5.359, SD 2.451, p = 0.035).ConclusionsDD is observed in a large majority of MV patients ≥5 days at some point of their ICU stay. Various patterns of DD are observed, including DD on initiation of mechanical ventilation and ICU-acquired DD.Trial registration clinicaltrials.gov Identifier # NCT00786526

Post-tracheostomy tracheo-oesophageal fistula – an unusual presentation

Tracheostomy, one of the oldest known surgical procedures in the history of medicine, is regularly performed in modern intensive care units. Acquired ulcerative tracheo-oesophageal fistula (TOF) is an uncommon but potentially fatal complication of tracheostomy. We report a case of ulcerative TOF with an unusual yet characteristic presentation, in a ventilator-dependent tracheostomised patient with Guillain-Barre syndrome. It presented as sudden progressive severe abdominal distension that was rhythmic with each ventilator breath. The predisposing factors, clinical features and preventive measures of post-tracheostomy TOF are discussed in this case report. Regular monitoring of tracheal tube cuff pressures and volumes, along with avoidance and treatment of various predisposing factors, are advisable for the prevention of this serious consequence.