Evaluation of an intervention to maintain endotracheal tube cuff pressure within therapeutic range.

BACKGROUND: Endotracheal tube cuff pressure must be kept within an optimal range that ensures ventilation and prevents aspiration while maintaining tracheal perfusion. OBJECTIVES: To test the effect of an intervention (adding or removing air) on the proportion of time that cuff pressure was between 20 and 30 cm H(2)O and to evaluate changes in cuff pressure over time. METHODS: A repeated-measure crossover design was used to study 32 orally intubated patients receiving mechanical ventilation for two 12-hour shifts (randomized control and intervention conditions). Continuous cuff pressure monitoring was initiated, and the pressure was adjusted to a minimum of 22 cm H(2)O. Caregivers were blinded to cuff pressure data, and usual care was provided during the control condition. During the intervention condition, cuff pressure alarm or clinical triggers guided the intervention. RESULTS: Most patients were men (mean age, 61.6 years). During the control condition, 51.7% of cuff pressure values were out of range compared with 11.1% during the intervention condition (P < .001). During the intervention, a mean of 8 adjustments were required, mostly to add air to the endotracheal tube cuff (mean 0.28 [SD, 0.13] mL). During the control condition, cuff pressure decreased over time (P < .001). CONCLUSIONS: The intervention was effective in maintaining cuff pressure within an optimal range, and cuff pressure decreased over time without intervention. The effect of the intervention on outcomes such as ventilator-associated pneumonia and tracheal damage requires further study.

Nanocrystalline hydroxyapatite bioceramic using microwave radiation: Synthesis and characterization.

In this work, we synthesized bioactive hydroxyapatite (Ca10(PO4)6(OH)2, HAp) ceramic powder in the lower-end of nano-regime using microwave radiation, which offers several advantages. The powder was synthesized using calcium nitrate tetrahydrate and sodium phosphate dibasic anhydrous as the starting materials. EDTA served as the complex reagent. The pH of the final suspension was adjusted to 9 by adding ammonium hydroxide. Applied microwave power of 600W, pH of the suspension, mole ratio of Ca/P in the staring chemicals, and the chelating effect of EDTA served as the factors in the synthesis of nanocrystalline HAp powder. The synthesized powder was studied using various characterizing techniques viz., XRD, SEM, HR-TEM, EDS, TG/DTA and FT-IR to determine powder morphology, particle-size, crystallinity, phases, elemental composition and thermal behavior. Results confirmed highly crystalline nano-powder (5-30nm) with elemental composition of Ca and P in HAp phase and possessed mixed (elliptical and rod-shape) morphology. Using the Scherrer formula, the average crystallite size was found to be 12nm. The FT-IR confirmed that the powder is of typical apatite structure. Thermal analysis showed a remarkably lower initial dehydroxylation temperature, compared to micron sized HAp, as reported in literature.

Assessment of endotracheal cuff pressure by continuous monitoring: a pilot study.

BACKGROUND: Endotracheal tube cuff pressure must be maintained within a narrow therapeutic range to prevent complications. Cuff pressure is measured and adjusted intermittently. OBJECTIVES: To assess the accuracy and feasibility of continuous monitoring of cuff pressure, describe changes in cuff pressure over time, and identify clinical factors that influence cuff pressure. METHODS: In a pilot study, data were collected for a mean of 9.3 hours on 10 patients who were orally intubated and receiving mechanical ventilation. Sixty percent of the patients were white, mean age was 55 years, and mean intubation time was 2.8 days. The initial cuff pressure was adjusted to a minimum of 20 cm H2O. The pilot balloon of the endotracheal tube was connected to a transducer and a pressure monitor. Cuff pressure was recorded every 0.008 seconds during a typical 12-hour shift and was reduced to 1-minute means. Patient care activities and interventions were recorded on a personal digital assistant. RESULTS: Values obtained with the cufflator-manometer and the transducer were congruent. Only 54% of cuff pressure measurements were within the recommended range of 20 to 30 cm H2O. The cuff pressure was high in 16% of measurements and low in 30%. No statistically significant changes over time were noted. Endotracheal suctioning, coughing, and positioning affected cuff pressure. CONCLUSIONS: Continuous monitoring of cuff pressure is feasible, accurate, and safe. Cuff pressures vary widely among patients.

Influence of oxide-based sintering additives on densification and mechanical behavior of tricalcium phosphate (TCP).

In this research, we studied and analyzed the effects of four different oxide-based sintering additives on densification, mechanical behavior, biodegradation and biocompatibility of tricalcium phosphate (TCP) bioceramics. Selective sintering additives were introduced into pure TCP ceramics, in small quantities, through homogeneous mixing, using a mortar and pestle. The consequent powders of different compositions were pressed into cylindrical compacts, uniaxially and sintered at elevated temperatures, 1150 degrees C and 1250 degrees C, separately in a muffle furnace. X-ray powder diffraction technique was used to analyze the phase-purity of TCP after sintering. Hardness of these sintered specimens was evaluated using a Vickers hardness tester. Sintered cylindrical samples were tested under uniaxial compressive loading, as a function of composition to determine their failure strength. Biodegradation studies conducted using simulated body fluid under dynamic environment, revealed that these additives could control the rate of resorption and hardness degradation of TCP ceramics.