Stephanie O'Connor

Use of a concentrated enteral nutrition solution to increase calorie delivery to critically ill patients: a randomized, double-blind, clinical trial

BACKGROUND Critically ill patients typically receive ∼60% of estimated calorie requirements. OBJECTIVES We aimed to determine whether the substitution of a 1.5-kcal/mL enteral nutrition solution for a 1.0-kcal/mL solution resulted in greater calorie delivery to critically ill patients and establish the feasibility of conducting a multicenter, double-blind, randomized trial to evaluate the effect of an increased calorie delivery on clinical outcomes. DESIGN A prospective, randomized, double-blind, parallel-group, multicenter study was conducted in 5 Australian intensive care units. One hundred twelve mechanically ventilated patients expected to receive enteral nutrition for ≥2 d were randomly assigned to receive 1.5 (n = 57) or 1.0 (n = 55) kcal/mL enteral nutrition solution at a rate of 1 mL/kg ideal body weight per hour for 10 d. Protein and fiber contents in the 2 solutions were equivalent. RESULTS The 2 groups had similar baseline characteristics (1.5 compared with 1.0 kcal/mL). The mean (±SD) age was 56.4 ± 16.8 compared with 56.5 ± 16.1 y, 74% compared with 75% were men, and the Acute Physiology and Chronic Health Evaluation II score was 23 ± 9.1 compared with 22 ± 8.9. The groups received similar volumes of enteral nutrition solution [1221 mL/d (95% CI: 1120, 1322 mL/d) compared with 1259 mL/d (95% CI: 1143, 1374 mL/d); P = 0.628], which led to a 46% increase in daily calories in the group given the 1.5-kcal/mL solution [1832 kcal/d (95% CI: 1681, 1984 kcal/d) compared with 1259 kcal/d (95% CI: 1143, 1374 kcal/d); P < 0.001]. The 1.5-kcal/mL solution was not associated with larger gastric residual volumes or diarrhea. In this feasibility study, there was a trend to a reduced 90-d mortality in patients given 1.5 kcal/mL [11 patients (20%) compared with 20 patients (37%); P = 0.057]. CONCLUSIONS The substitution of a 1.0- with a 1.5-kcal/mL enteral nutrition solution administered at the same rate resulted in a 46% greater calorie delivery without adverse effects. The results support the conduct of a large-scale trial to evaluate the effect of increased calorie delivery on clinically important outcomes in the critically ill.

Characteristics of plasma NOx levels in severe sepsis: high interindividual variability and correlation with illness severity, but lack of correlation with cortisol levels.

Objectives  Nitric oxide (NO) concentrations are elevated in sepsis and their vasodilatory action may contribute to the development of hyperdynamic circulatory failure. Hydrocortisone infusion has been reported to reduce nitric oxide metabolite (NOx) concentrations and facilitate vasopressor withdrawal in septic shock. Our aim was to determine whether NOx concentrations relate to (i) protocol‐driven vasopressor initiation and withdrawal and (ii) plasma cortisol concentrations, from endogenous and exogenous sources. Demonstration of a relation between NOx, cortisol and vasopressor requirement may provide an impetus towards the study of hydrocortisone‐mediated NOx suppression as a tool in sepsis management.

Tracheostomy Tube Type and Inner Cannula Selection Impact Pressure and Resistance to Air Flow

BACKGROUND: Advancements in tracheostomy tube design now provide clinicians with a range of options to facilitate communication for individuals receiving ventilator assistance through a cuffed tube. Little is known about the impact of these modern design features on resistance to air flow. METHODS: We undertook a bench model test to measure pressure-flow characteristics and resistance of a range of tubes of similar outer diameter, including those enabling subglottic suction and speech. A constant inspiratory ± expiratory air flow was generated at increasing flows up to 150 L/min through each tube (with or without optional, mandatory, or interchangeable inner cannula). Driving pressures were measured, and resistance was calculated (cm H2O/L/s). RESULTS: Pressures changed with increasing flow (P < .001) and tube type (P < .001), with differing patterns of pressure change according to the type of tube (P < .001) and direction of air flow. The single-lumen reference tube encountered the lowest inspiratory and expiratory pressures compared with all double-lumen tubes (P < .001); placement of an optional inner cannula increased bidirectional tube resistance by a factor of 3. For a tube with interchangeable inner cannulas, the type of cannula altered pressure and resistance differently (P < .001); the speech cannula in particular amplified pressure-flow changes and increased tube resistance by more than a factor of 4. CONCLUSIONS: Tracheostomy tube type and inner cannula selection imposed differing pressures and resistance to air flow during inspiration and expiration. These differences may be important when selecting airway equipment or when setting parameters for monitoring, particularly for patients receiving supported ventilation or during the weaning process.

Impact of nasogastric tubes on swallowing physiology in older, healthy subjects: A randomized controlled crossover trial

BACKGROUND & AIMS The presence of a nasogastric tube (NGT) affects swallowing physiology but not function in healthy young adults. The swallowing mechanism changes with increasing age, therefore the impact of a NGT on swallowing in elderly individuals is likely to be different but is not yet known. The aims of this study were to determine the effects of NGTs of different diameter on (1) airway penetration-aspiration, (2) pharyngeal residue, and (3) pharyngeal transit, in older healthy subjects. METHODS Randomized controlled crossover design. Healthy elderly volunteers underwent 3 modified barium swallow studies in which multiple diet and fluid consistencies were swallowed under the following conditions: (A) no NGT (control), (B) fine bore NGT, and (C) wide bore NGT. The control condition was assessed first to establish baseline swallowing function, then NGT order was randomly allocated. RESULTS Of the 15 volunteers (median age 65 years, range 60-81) complete data sets were obtained for 9 (4 with allocation order ABC; 5 with ACB). Wide bore NGT data could not be obtained for 6 volunteers mainly due to tube intolerance. The presence of a NGT was associated with: (i) an increase in airway penetration-aspiration (fine bore NGT with serial liquid swallows and puree) (p < 0.01); (ii) increased pharyngeal residue (p < 0.05) in the pyriform sinus (fine bore NGT with puree); and in the valleculae (both fine and wide bore NGT with soft solids); and (iii) an increase in pharyngeal transit duration regardless of consistency (p < 0.01), with longest swallowing durations with the widest tube. CONCLUSIONS NGT presence increases airway penetration-aspiration, pharyngeal residue and prolongs transit through the pharynx in older healthy individuals. Consideration of NGT impact on swallowing during concurrent oral and enteral feeding is recommended, with further systematic investigation required in elderly patients recovering from critical illness. Clinical trial registry Australia & New Zealand Clinical Trials Registry (ACTRN12613000577718).

Patterns of return to oral intake and decannulation post-tracheostomy across clinical populations in an acute inpatient setting

BACKGROUND Dysphagia is often a comorbidity in patients who require a tracheostomy, yet little is known about patterns of oral intake commencement in tracheostomized patients, or how patterns may vary depending on the clinical population and/or reason for tracheostomy insertion. AIMS To document patterns of clinical management around the commencement of oral intake throughout hospital admission and along the decannulation pathway in patients with a new tracheostomy, and to examine the nature of variability across multiple clinical populations. METHODS & PROCEDURES A 12-month retrospective review of 126 patients who had undergone an acute tracheostomy was conducted. Within the cohort, patients were further classified into eight clinical populations representing specialty areas within the tertiary referral centre. Data were collected on timing of milestones and patterns of clinical management related to oral and enteral feeding and decannulation. Relationships between temporal variables were calculated, in addition to descriptive analysis of the overall cohort and by clinical population. OUTCOMES & RESULTS Median temporal markers of patient progression post-tracheostomy insertion for the cohort were: continuous cuff deflation after 7.5 days, commencement of oral intake after 10.5 days, decannulation after 15 days and cessation of enteral nutrition (EN) after 17 days. However, considerable individual variation and differences between clinical populations was observed. Overall, 86% of the cohort returned to oral intake, although 25% were discharged with EN via a gastrostomy. A total of 86% of the group were decannulated by hospital discharge. Oral intake was introduced at every stage of the decannulation pathway, including prior to cuff deflation, but the majority of patients commenced diet/fluids following cuff deflation or with an uncuffed tube in situ, and most patients who ceased EN did so following decannulation. Commencement of oral intake was evenly split between the intensive care unit (ICU) and the wards. Increased time to commencement of oral intake correlated with increased time to decannulation (r = .805, p = .001), and increased time to decannulation correlated with increased hospital length of stay (r = .687, p = .006). Whilst cohort patterns were observed within the heterogeneous group, sub-analysis revealed distinct patterns of oral intake management across the different clinical populations. CONCLUSIONS & IMPLICATIONS The data provide benchmarks enabling comparison by overall cohort as well as by specialist clinical populations, each with differing reasons for tracheostomy insertion. The data would suggest that tracheostomy patients should not be looked upon as a singular cohort; rather, evaluation of factors with specific attention made to underlying aetiology and individual clinical presentation is essential.

Establishing phonation using the Blom® tracheostomy tube system: a report of three cases post cervical spinal cord injury

Objective: Mechanically ventilated patients with cervical spinal cord injury (CSCI) have few options for verbal communication in the acute phase post injury. Leak speech and one-way speaking valves can restore laryngeal airflow; however, both methods require deflation of the tracheostomy cuff which is not always possible. The Blom® tracheostomy tube system (Blom® TTS) provides an option for restoring speech while maintaining cuff inflation, through insertion of a flexible tapered speech cannula into a fenestrated outer cannula. Two studies have reported on the speech achieved with this tube, yet these focused on mixed clinical groups and only examined immediate changes to communication. Longer-term use and patient perceptions of communicating with this system have not been reported. Methods: This paper describes the introduction of the Blom® TTS into three individuals with tetraplegia following CSCI and follows their outcomes throughout their intensive care admission. Results: The tube was successfully placed in two of the three participants. Of these two, phonation was easily established and high levels of patient-perceived comfort and ease and quality of voicing were found when speaking and breathing with the Blom® speech cannula in situ. One patient was sensitive to respiratory changes imposed by the three different inner cannulas of the Blom® TTS and did not complete weaning with the speech cannula in situ. Conclusions: The current research adds support for early restoration of speech via a cuffed tracheostomy during mechanical ventilation in the intensive care unit. Long-term use however identified some potential issues with patient tolerance and safety of the different inner cannulas which may need to be considered for longer-term clinical management. The cases highlight differences in use of the Blom® TTS depending on the degree of respiratory impairment and prognosis for weaning following CSCI.

Impact of nasogastric tubes on swallowing physiology in older healthy volunteers: A randomised controlled trial

Dysphagia Research Society Annual Meeting and Post-Graduate Course March 13–16, 2013 The Fairmont Olympic Hotel, Seattle, Washington Springer Science+Business Media New York 2013