Daniel F Fisher

Comparison of commercial and noncommercial endotracheal tube-securing devices.

BACKGROUND: Tracheal intubation is used to establish a secure airway in patients who require mechanical ventilation. Unexpected extubation can have serious complications, including airway trauma and death. Various methods and devices have been developed to maintain endotracheal tube (ETT) security. Associated complications include pressure ulcers due to decreased tissue perfusion. Device consideration includes ease of use, rapid application, and low exerted pressure around the airway. METHODS: Sixteen ETT holders were evaluated under a series of simulated clinical conditions. ETT security was tested by measuring distance displaced after a tug. Nine of the 16 methods could be evaluated for speed of moving the ETT to the opposite side of the mouth. Sensors located on a mannequin measured applied forces when the head was rotated vertically or horizontally. Data were analyzed using multivariate analysis of variance, with P < .05. RESULTS: Median displacement of the ETT by the tug test was 0 cm (interquartile range of 0.0–0.10 cm, P < .001). The mean time to move the ETT from one side of the mouth to the other ranged from 1.25 ± 0.2 s to 34.4 ± 3.4 s (P < .001). Forces applied to the face with a vertical head lift ranged from < 0.2 newtons (N) to a maximum of 3.52 N (P < .001). Forces applied to the face with a horizontal rotation ranged from < 0.2 N to 3.52 N (P < .001). Commercial devices produced greater force than noncommercial devices. CONCLUSIONS: Noncommercial airway holders exert less force on a patients face than commercial devices. Airway stability is affected by the type of securing method. Many commercial holders allow for rapid but secure movement of the artificial airway from one side of the mouth to the other.

Tracheostomy Tube Change Before Day 7 Is Associated With Earlier Use of Speaking Valve and Earlier Oral Intake

BACKGROUND: Presence of a tracheostomy tube often decreases the patients ability to communicate and to tolerate oral intake. The initial tracheostomy tube change is often recommended between day 7 and 14 post insertion. Local guidelines permit tracheostomy tube change 5 days after insertion. OBJECTIVE: We hypothesized that changing tracheostomy tubes before day 7 is associated with earlier use of a speaking valve as well as earlier oral intake, compared to changing tracheostomy tubes after 7 days. METHODS: We prospectively enrolled 130 admitted subjects, after tracheostomy placement to a respiratory care unit between July 2008 and May 2010. Subject data were recorded from the electronic medical record. The primary end point was the time from tracheostomy tube placement to tolerating speaking valve. The secondary end point was the time from tracheostomy tube placement to tolerating oral intake. Complications of tracheostomy tube change were recorded. RESULTS: Thirty-eight subjects had the first tracheostomy tube change before 7 days (early group), and 92 subjects had the first tracheostomy tube change after 7 days (late group). The early group tolerated a speaking valve significantly sooner than the late group (7 d vs 12 d, P = .001). The early group also tolerated oral intake significantly sooner (10 d vs 20 d, P = .04). After change of the tracheostomy tube, the time to tolerating oral feeding was 5.5 days in both groups. There was no significant difference in time to decannulation between the groups. The early group had a shorter respiratory care unit stay (11 d vs 17 d, P = .001) and a shorter hospital stay (P = .05) than the late group. There was no difference in survival. There were no complications associated with tracheostomy tube change. CONCLUSIONS: Tracheostomy tube change before day 7 is associated with earlier ability to tolerate speaking valve and oral intake. In this series, early tracheostomy tube change was not associated with an increased rate of complications.

Evaluation of an Automated Endotracheal Tube Cuff Controller During Simulated Mechanical Ventilation

BACKGROUND: Maintaining endotracheal tube cuff pressure within a narrow range is an important factor in patient care. The goal of this study was to evaluate the IntelliCuff against the manual technique for maintaining cuff pressure during simulated mechanical ventilation with and without movement. METHODS: The IntelliCuff was compared to the manual technique of a manometer and syringe. Two independent studies were performed during mechanical ventilation: part 1, a 2-h trial incorporating continuous mannikin head movement; and part 2, an 8-h trial using a stationary trachea model. We set cuff pressure to 25 cm H2O, PEEP to 10 cm H2O, and peak inspiratory pressures to 20, 30, and 40 cm H2O. Clinical importance was defined as both statistically significant (P < .05) and clinically significant (pressure change [Δ] > 10%). RESULTS: In part 1, the change in cuff pressure from before to after ventilation was clinically important for the manual technique (P < .001, Δ = −39.6%) but not for the IntelliCuff (P = .02, Δ = 3.5%). In part 2, the change in cuff pressure from before to after ventilation was clinically important for the manual technique (P = .004, Δ = −14.39%) but not for the IntelliCuff (P = .20, Δ = 5.65%). CONCLUSIONS: There was a clinically important drop in manually set cuff pressure during simulated mechanical ventilation in a stationary model and an even larger drop with movement, but this was significantly reduced by the IntelliCuff in both scenarios. Additionally, we observed that cuff pressure varied directly with inspiratory airway pressure for both techniques, leading to elevated average cuff pressures.

Performance of Leak Compensation in All-Age ICU Ventilators During Volume-Targeted Neonatal Ventilation: A Lung Model Study

BACKGROUND: Volume-targeted ventilation is increasingly used in low birthweight infants because of the potential for reducing volutrauma and avoiding hypocapnea. However, it is not known what level of air leak is acceptable during neonatal volume-targeted ventilation when leak compensation is activated concurrently. METHODS: Four ICU ventilators (Servo-i, PB980, V500, and Avea) were compared in available invasive volume-targeted ventilation modes (pressure control continuous spontaneous ventilation [PC-CSV] and pressure control continuous mandatory ventilation [PC-CMV]). The Servo-i and PB980 were tested with (+) and without (−) their proximal flow sensor. The V500 and Avea were tested with their proximal flow sensor as indicated by their manufacturers. An ASL 5000 lung model was used to simulate 4 neonatal scenarios (body weight 0.5, 1, 2, and 4 kg). The ASL 5000 was ventilated via an endotracheal tube with 3 different leaks. Two minutes of data were collected after each change in leak level, and the asynchrony index was calculated. Tidal volume (VT) before and after the change in leak was assessed. RESULTS: The differences in delivered VT between before and after the change in leak were within ±5% in all scenarios with the PB980 (−/+) and V500. With the Servo-i (−/+), baseline VT was ≥10% greater than set VT during PC-CSV, and delivered VT markedly changed with leak. The Avea demonstrated persistent high VT in all leak scenarios. Across all ventilators, the median asynchrony index was 1% (interquartile range 0–27%) in PC-CSV and 1.8% (0–45%) in PC-CMV. The median asynchrony index was significantly higher in the Servo-i (−/+) than in the PB980 (−/+) and V500 in 1 and 2 kg scenarios during PC-CSV and PC-CMV. CONCLUSIONS: The PB980 and V500 were the only ventilators to acclimate to all leak scenarios and achieve targeted VT. Further clinical investigation is needed to validate the use of leak compensation during neonatal volume-targeted ventilation.

Effects of Leak Compensation on Patient-Ventilator Synchrony During Premature/Neonatal Invasive and Noninvasive Ventilation: A Lung Model Study

BACKGROUND: During both nasal noninvasive ventilation (NIV) and invasive ventilation of neonates, the presence of air leaks causes triggering and cycling asynchrony. METHODS: Five ICU ventilators (PB840, PB980, Servo-i, V500, and Avea) were compared in available invasive ventilation and NIV ventilator modes (pressure control continuous spontaneous ventilation [PC-CSV] and pressure control continuous mandatory ventilation [PC-CMV]). The V500 and Avea do not provide PC-CSV and PC-CMV in NIV. The Servo-i and Avea were tested with and without their proximal flow sensor. The ASL 5000 lung model (version 3.5) was used to simulate 4 neonatal scenarios (body weight 0.5, 1, 2, and 4 kg). The ASL 5000 was ventilated via endotracheal tube (invasive ventilation) or nasal cannula (NIV) with 4 different leaks. RESULTS: The Avea (without flow sensor) during invasive ventilation and Servo-i and PB840 during NIV were not triggered by inspiratory efforts of the ASL 5000 at the baseline leak in the 0.5 kg scenario. In invasive ventilation, overall (median) asynchrony index was significantly lower with the PB980 (1%) and V500 (3%) than with the Servo-i (with flow sensor, 50%; without flow sensor, 50%) and Avea (with sensor, 50%; without sensor, 62%) (P < .05 for all comparisons). The PB840 (33%) was significantly different from all ventilators (P < .05). In NIV, the asynchrony index was significantly lower in PB980 (2%) than in the Servo-i (with sensor, 100%; without sensor, 100%) and PB840 (75%) (P < .05 for both). There was no difference in asynchrony index between PC-CSV and PC-CMV in all tested conditions and ventilators. CONCLUSIONS: The ability of leak compensation to prevent asynchronous breathing varied widely between ventilators and lung mechanics. The PB980 and V500 were the only two ventilators to acclimate to all leak scenarios in invasive ventilation, and PB980 was the only ventilator to acclimate to all leak scenarios in NIV.

Performance of the PneuX System: A Bench Study Comparison With 4 Other Endotracheal Tube Cuffs

BACKGROUND: Cuff design affects microaspiration, a risk factor for pneumonia. We questioned whether the PneuX low-volume fold-free cuff design would prevent cuff leakage and maintain the same tracheal wall pressure as high-volume, low-pressure (HVLP) cuffs. METHODS: We evaluated 4 HVLP-cuffed endotracheal tubes (ETTs), Hi-Lo (polyvinyl chloride [PVC]), Microcuff (polyurethane [PU]), SealGuard (PU + tapered), and TaperGuard (PVC + tapered), and the PneuX with its dedicated tracheal seal monitor. In Part 1, we determined tracheal wall pressure using each cuffs capacity to support water columns across recommended intracuff pressures. In Part 2, we evaluated the tracheal seal monitor function at recommended settings. In Part 3, we compared leakage volumes of all ETTs during 30 min of simulated mechanical ventilation or during 8 h if no leak occurred. Parts 1 and 3 were performed with/without lubrication and PEEP. RESULTS: In Part 1, PneuX cuffs exerted an average tracheal wall pressure of 27.4 ± 2.4 cm H2O at the recommended intracuff pressure of approximately 80 cm H2O. Tracheal wall pressure did not differ among HVLP cuffs (19.6 ± 1.4 to 29.5 ± 1.4 cm H2O). In Part 2, preinflation intracuff pressure affected the time to obtain tracheal seal monitor pressure attainment (P < .01). The tracheal seal monitor generated average calculated tracheal wall pressure of 33.4 ± 1.2 cm H2O. In Part 3, PneuX ETT showed no leak across 8 h for all trials. Overall, leakage volume was lower with PU (P < .01) and PneuX (P < .01) than with PVC cuffs, regardless of shape, and lower with lubrication and/or PEEP (all P < .01). In each HVLP cuff, lubrication alone eliminated leak at an intracuff pressure of ≤30 cm H2O. CONCLUSIONS: The PneuX cuff generally exerted acceptable tracheal wall pressure, but the tracheal wall pressure monitor allowed pressures exceeding 30 cm H2O in some trials and was the only ETT to prevent leak in all tests. For HVLP cuffs, leak was reduced by PU and PEEP and eliminated by lubrication.

Respiratory Management of Perioperative Obese Patients.

With a rising incidence of obesity in the United States, anesthesiologists are faced with a larger volume of obese patients coming to the operating room as well as obese patients with ever-larger body mass indices (BMIs). While there are many cardiovascular and endocrine issues that clinicians must take into account when caring for the obese patient, one of the most prominent concerns of the anesthesiologist in the perioperative setting should be the status of the lung. Because the pathophysiology of reduced lung volumes in the obese patient differs from that of the ARDS patient, the best approach to keeping the obese patients lung open and adequately ventilated during mechanical ventilation is unique. Although strong evidence and research are lacking regarding how to best ventilate the obese surgical patient, we aim with this review to provide an assessment of the small amount of research that has been conducted and the pathophysiology we believe influences the apparent results. We will provide a basic overview of the anatomy and pathophysiology of the obese respiratory system and review studies concerning pre-, intra-, and postoperative respiratory care. Our focus in this review centers on the best approach to keeping the lung recruited through the prevention of compression atelectasis and the maintaining of physiological lung volumes. We recommend the use of PEEP via noninvasive ventilation (NIV) before induction and endotracheal intubation, the use of both PEEP and periodic recruitment maneuvers during mechanical ventilation, and the use of PEEP via NIV after extubation. It is our hope that by studying the underlying mechanisms that make ventilating obese patients so difficult, future research can be better tailored to address this increasingly important challenge to the field of anesthesia.

Initial mechanical ventilator settings and lung protective ventilation in the ED

OBJECTIVE Mechanical ventilation with low tidal volumes has been shown to improve outcomes for patients both with and without acute respiratory distress syndrome. This study aims to characterize mechanically ventilated patients in the emergency department (ED), describe the initial ED ventilator settings, and assess for associations between lung protective ventilation strategies in the ED and outcomes. METHODS This was a multicenter, prospective, observational study of mechanical ventilation at 3 academic EDs. We defined lung protective ventilation as a tidal volume of less than or equal to 8 mL/kg of predicted body weight and compared outcomes for patients ventilated with lung protective vs non-lung protective ventilation, including inhospital mortality, ventilator days, intensive care unit length of stay, and hospital length of stay. RESULTS Data from 433 patients were analyzed. Altered mental status without respiratory pathology was the most common reason for intubation, followed by trauma and respiratory failure. Two hundred sixty-one patients (60.3%) received lung protective ventilation, but most patients were ventilated with a low positive end-expiratory pressure, high fraction of inspired oxygen strategy. Patients were ventilated in the ED for a mean of 5 hours and 7 minutes but had few ventilator adjustments. Outcomes were not significantly different between patients receiving lung protective vs non-lung protective ventilation. CONCLUSIONS Nearly 40% of ED patients were ventilated with non-lung protective ventilation as well as with low positive end-expiratory pressure and high fraction of inspired oxygen. Despite a mean ED ventilation time of more than 5 hours, few patients had adjustments made to their ventilators.

Emergency Department Blood Gas Utilization and Changes in Ventilator Settings

BACKGROUND: Mechanically ventilated patients increasingly spend hours in emergency department beds before ICU admission. This study evaluated the performance of blood gases in mechanically ventilated subjects in the emergency department and subsequent changes to mechanical ventilation settings. METHODS: This was a multi-center, prospective, observational study of subjects ventilated in the emergency department, conducted at 3 academic emergency departments from July 2011 to March 2013. We measured the rate of arterial blood gas (ABG) and venous blood gas (VBG) analysis, and we assessed the associations between the conditions of hypoxemia, hyperoxia, hypercapnia, or acidemia and changes to mechanical ventilator settings. RESULTS: Of 292 ventilated subjects, 17.1% did not have a blood gas sent in the emergency department. Ventilator changes were made significantly more frequently for subjects who had an ABG as the initial blood gas sent in the emergency department (odds ratio 2.70, 95% CI 1.46–4.99, P = .002). However, findings of hypoxemia, hyperoxia, hypercapnia, or acidemia were not correlated with ventilator adjustments. CONCLUSIONS: In this prospective observational study of subjects mechanically ventilated in the emergency department, the majority had a blood gas checked while in the emergency department. While ABGs were associated with having changes made to ventilator settings in the emergency department, clinical findings of hypoxemia, hyperoxia, hypercapnia, and acidemia were not. Inattention to blood gas results may lead to missed opportunities in guiding ventilator changes in the emergency department.

Duration of Mechanical Ventilation in the Emergency Department

Introduction Due to hospital crowding, mechanically ventilated patients are increasingly spending hours boarding in emergency departments (ED) before intensive care unit (ICU) admission. This study aims to evaluate the association between time ventilated in the ED and in-hospital mortality, duration of mechanical ventilation, ICU and hospital length of stay (LOS). Methods This was a multi-center, prospective, observational study of patients ventilated in the ED, conducted at three academic Level I Trauma Centers from July 2011 to March 2013. All consecutive adult patients on invasive mechanical ventilation were eligible for enrollment. We performed a Cox regression to assess for a mortality effect for mechanically ventilated patients with each hour of increasing LOS in the ED and multivariable regression analyses to assess for independently significant contributors to in-hospital mortality. Our primary outcome was in-hospital mortality, with secondary outcomes of ventilator days, ICU LOS and hospital LOS. We further commented on use of lung protective ventilation and frequency of ventilator changes made in this cohort. Results We enrolled 535 patients, of whom 525 met all inclusion criteria. Altered mental status without respiratory pathology was the most common reason for intubation, followed by trauma and respiratory failure. Using iterated Cox regression, a mortality effect occurred at ED time of mechanical ventilation > 7 hours, and the longer ED stay was also associated with a longer total duration of intubation. However, adjusted multivariable regression analysis demonstrated only older age and admission to the neurosciences ICU as independently associated with increased mortality. Of interest, only 23.8% of patients ventilated in the ED for over seven hours had changes made to their ventilator. Conclusion In a prospective observational study of patients mechanically ventilated in the ED, there was a significant mortality benefit to expedited transfer of patients into an appropriate ICU setting.