Volume 2 Supplement 1

18th International Symposium on Intensive Care and Emergency Medicine

Open Access

Aspiration of airway dead space (ASPIDS) in mechanically ventilated patients

  • E De Robertis1,
  • G Servillo1,
  • F Rossano1,
  • B Jonson2 and
  • R Tufano1
Critical Care19982(Suppl 1):P083

https://doi.org/10.1186/cc213

Published: 1 March 1998

Introduction

Alveolar ventilation can be improved and CO2 clearance enhanced by reducing dead space. We studied a system for the aspiration of gas from the airway dead space (Vdaw) denoted ASPIDS. During ASPIDS, in the late expiration, CO2 rich gas is aspirated from the distal end of the tracheal tube; simultaneously fresh gas is injected in the inspiratory line. Our hypothesis was that CO2-laden gas in the Vdaw could be eliminated and, keeping alveolar ventilation constant, a reduction in minute ventilation (MV) and airway pressure (Paw) achieved.

Materials and Methods

Six patients (4m/2f, mean age 56 ± 23 years) mechanically ventilated for cerebral pathologies (Crs: 78 ± 20 ml/cmH2O) with a computer controlled Servo Ventilator 900C (basal ventilation: MV: 7.7 l/min; RR: 12.7; Ti: 33%; Tpaus: 5%; PEEP: 5 cmH2O), were studied. The computer controls 2 solenoid valves for aspiration and injection. The aim was to keep PaCO2 constant during ASPIDS while decreasing MV. ASPIDS was expected to clear from CO2 the volume of connecting tubings (ie 150 ml). Consequently, MV was decreased, during ASPIDS, of 150 × RR (ie 1900 ml). Data collected after 20 min of ASPIDS were compared with baseline ventilation using a T test. The following parameters were recorded: HR, mABP, MV, Pawpeak, VCO2, blood gases.

Results

Patients were stable during ASPIDS. PEEP level was maintained and no PEEPi developed. No side effects were observed.

Conclusions

From our preliminary results, ASPIDS appears to be a new safe and promising method that improves the efficiency of ventilation, decreases the pressure required, and reduces the potential for lung injury during mechanical ventilation.

Table

 

MV (L)

Pawpeak (cmH2O)

VCO2

PaCO2 (mmHg)

PaO2 (mmHg)

HR

mABP (mmHg)

Baseline

7.7

24.4

171.3

36.2

103.0

94.3

67.2

ASPIDS

5.8*

16.2*

176.0

36.0

100.1

89.2

68.7

Authors’ Affiliations

(1)
Department of Anaesthesia and Intensive Care, University of Naples `Federico II'
(2)
Department of Clinical Physiology, Lund University Hospital

References

  1. Johnson B, et al: . Eur Resp J. 1990, 3: 1202-Google Scholar
  2. Ravenscraft SA, et al: . Am Rev Resp Dis. 1993, 148: 345-351.PubMedView ArticleGoogle Scholar
  3. Taskar V, et al: . Chest. 1995, 108: 196-202. 10.1378/chest.108.1.196.PubMedView ArticleGoogle Scholar

Copyright

© Current Science Ltd 1998

Advertisement