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F J Tasota

Publications and source records attributed to F J Tasota.

At least 19 recordsLinked to original sources
PubMed2001

Monitoring and humidification during tracheal gas insufflation.

In order to use tracheal gas insufflation (TGI) in a safe and effective manner, it is important to understand potential interactions between TGI and the mechanical ventilator that may impact upon gas delivery and carbon dioxide (CO2) elimination. Furthermore, potentially serious complications secondary to insufflation of cool, dry gas directly into the airway and the possibility of tube occlusion must be considered during use of this adjunct modality to mechanical ventilation. Regardless of the delivery modality (continuous TGI, expiratory TGI, reverse TGI, or bidirectional TGI), conventional respiratory monitoring is required. However, TGI with mechanical ventilation can alter tidal volume and peak inspiratory pressure and can lead to the development of intrinsic positive end-expiratory pressure. Therefore, depending on the gas delivery technique used, it is important to carefully monitor these ventilatory parameters for TGI-induced changes and understand the potential need for adjustments to ventilator settings to facilitate therapy and avoid problems. Optimally, gas insufflated by the TGI catheter should be conditioned by addition of heat and humidity to prevent mucus plug formation and potential damage to the tracheal mucosa. Finally, patients must be closely monitored for increases in peak inspiratory pressure from obstruction of the tracheal tube and should have the TGI catheter removed and inspected every 8-12 hours to assess for plugs.

Airway Resistance↗
PubMed2001

Effects of continuous, expiratory, reverse, and bi-directional tracheal gas insufflation in conjunction with a flow relief valve on delivered tidal volume, total positive end-expiratory pressure, and carbon dioxide elimination: a bench study.

INTRODUCTION: Tracheal gas insufflation (TGI) can increase total positive end-expiratory pressure (total-PEEP) when flow is delivered in a forward direction, necessitating adjustments to maintain total-PEEP constant. When TGI is delivered throughout the respiratory cycle, additional adjustments are needed to maintain tidal volume (V(T)) constant. OBJECTIVE: Determine if bi-directional TGI (bi-TGI) (simultaneous flows toward the lungs and upper airway) in combination with a flow relief valve eliminates the increase in total-PEEP and maintains a constant V(T), thus simplifying TGI administration. METHODS: Using an artificial lung model and pressure control ventilation, we studied the effect of TGI at 10 L/min on inspired V(T), total-PEEP, and CO(2) elimination during 6 conditions: (1) control (no TGI, no catheter in the airway), (2) baseline (catheter in the airway but no TGI), (3) continuous TGI, (4) expiratory TGI, (5) reverse TGI, and (6) bi-TGI. Each condition was studied under 3 inspiration-expiration ratios (1:1, 1:2, and 2:1). A preset flow relief valve was inserted into the ventilator circuit during all TGI conditions with continuous flow. SETTING: University research laboratory. RESULTS: CO(2) elimination efficiency was similar under all conditions. Total-PEEP increased with continuous TGI and expiratory TGI, decreased during reverse TGI, and was unchanged during bi-TGI. With the flow relief valve in place, and no adjustment in mechanical ventilation, the change in minute ventilation ranged from 0% to 10%, with the least change during bi-TGI (0-5%). During bi-TGI, gas flow was equivalent in both directions during dynamic conditions and the flow relief valve consistently removed gas at 10 L/min under various pressures. CONCLUSIONS: Our data from an artificial lung model support that continuous bi-TGI minimizes the change in total-PEEP seen during other TGI modalities. The flow relief valve compensated for the extra gas volume delivered by the TGI catheter, thereby eliminating the need to make ventilator adjustments. Used in combination with a flow relief valve, bi-TGI appears to offer unique advantages by providing a simpler method to deliver TGI. Further testing is indicated to determine if similar benefits occur in the clinical setting.

Airway Resistance↗
PubMed2000

Auto-positive end-expiratory pressure during tracheal gas insufflation: testing a hypothetical model.

OBJECTIVE: The major benefit of tracheal gas insufflation (TGI) is an increase in CO2 elimination efficiency by removal of CO2 from the anatomical deadspace. In conjunction with mechanical ventilation, TGI may also alter variables that affect CO2 elimination, such as minute ventilation and peak airway pressure (peak Paw) and cause the development of auto-positive end-expiratory pressure (auto-PEEP). We tested the hypothesis that TGI-induced auto-PEEP alters ventilatory variables. We predicted that TGI-induced auto-PEEP offsets the beneficial effects of TGI on CO2 elimination and that keeping total PEEP (ventilator PEEP + auto-PEEP) constant enhances the CO2 elimination efficiency afforded by TGI. DESIGN: Prospective study of two series of patients with acute respiratory distress syndrome receiving mechanical ventilation. SETTING: Intensive care units at a university medical center. PATIENTS: Each series consisted of eight sequential hypercapnic patients. INTERVENTIONS: In series 1, we examined the effect of continuous TGI at 0 and 10 L/min on PaCO2, without compensating for the development of auto-PEEP. In series 2, we examined this same effect of continuous TGI while reducing ventilator PEEP to keep total PEEP constant. TGI-induced auto-PEEP was calculated based on dynamic compliance measurements during zero TGI flow conditions (deltaV/deltaP) after averaging the two baseline values for peak Paw and tidal volume and assuming compliance did not change between the zero TGI and TGI flow conditions (deltaVTGI/deltaPTGI). MEASUREMENTS AND MAIN RESULTS: In series 1, total PEEP increased from 13.2 +/- 3.2 cm H2O to 17.8 +/- 3.5 cm H2O without compensation for auto-PEEP (p = .01). PaCO2 decreased (p = .03) from 56.2 +/- 10.6 mm Hg (zero TGI) to 52.9 +/- 9.3 mm Hg (TGI at 10 L/min), a 6% decrement. In series 2, total PEEP was unchanged (p = NS). PaCO2 decreased (p = .03) from 59.5 +/- 10.4 mm Hg (zero TGI) to 52.2 +/- 8.3 mm Hg (TGI at 10 L/min), a 12% decrement. There was no significant change in PaO2; there were no untoward hemodynamic effects in either series. CONCLUSIONS: These data are consistent with the hypothesis that mechanical ventilation + TGI causes an increase in auto-PEEP that can blunt CO2 elimination. In addition to the ventilator modifications necessary to keep ventilatory variables constant when TGI is used, it is also necessary to reduce ventilator PEEP to keep total PEEP constant and further enhance CO2 elimination efficiency.

Aged↗
PubMed2000

Tracheal gas insufflation. Limits of efficacy in adults with acute respiratory distress syndrome.

In mechanically ventilated adults with acute respiratory distress syndrome (ARDS), peak airway pressures (Paw(peak)) above 35 cm H(2)O may increase the risk of barotrauma or volutrauma. Tracheal gas insufflation (TGI), an adjunctive ventilatory technique, may facilitate a reduction in set inspiratory pressure in these patients, and thereby in the tidal volume (VT) and Paw(peak) used in their ventilation, without a consequent increase in arterial carbon dioxide tension (PaCO(2)). The purpose of this study was to: (1) assess the limits of efficacy of continuous TGI at two levels of decreased mechanical ventilatory support; and (2) determine an appropriate time interval after initiation of TGI at which to evaluate response. We prospectively studied eight adults with ARDS and increased airway pressures (40.2 +/- 2.7 cm H(2)O) who were managed with pressure-control ventilation (PCV). After obtaining baseline ventilatory and hemodynamic measures, we initiated TGI at 10 L/min, adjusting ventilator positive-end expiratory pressure (PEEP) to maintain baseline VT, and decreased the set inspiratory pressure by 5 cm H(2)O. Data were obtained after 30 and 60 min. Set inspiratory pressure was then decreased by an additional 5 cm H(2)O (total: 10 cm H(2)O), and data were again obtained after 30 min. Baseline (zero TGI) measures were then again recorded. Thirty minutes after decreasing the set inspiratory pressure by 5 cm H(2)O with TGI at 10 L/min, there was a 15% decrease in Paw(peak) and a 16% decrease in VT as compared with their baseline values. However, Pa(CO(2)) remained constant (59 +/- 10 mm Hg versus 57 +/- 6 mm Hg) (p = NS). There was no change in Pa(O(2)) or in hemodynamic variables, and no differences between variables, at 30 min versus 60 min in seven subjects. The remaining subject did not tolerate the reduction in set inspiratory pressure for 60 min. Thirty minutes after the set inspiratory pressure was decreased by 10 cm H(2)O with TGI at 10 L/min, there was a 26% decrease in Paw(peak) and a 26% decrease in VT. However, Pa(CO(2)) increased by 19% and Pa(O(2)) decreased by 13%. Six subjects completed this phase of the protocol for 30 min, and one subject completed it for 60 min. TGI can be used to rapidly facilitate a 5 cm H(2)O reduction in set inspiratory pressure without an increase in Pa(CO(2)). The ability to achieve a 5 cm H(2)O reduction in set inspiratory pressure without adverse physiologic effects was evident within 30 min. Attempts to further reduce set inspiratory pressure were not successful.

Acute Disease↗