The effect of increased apparatus dead space and tidal volumes on carbon dioxide elimination and oxygen saturations in a low-flow anesthesia system.

Research output: Contribution to journalArticle


STUDY OBJECTIVE: To determine if a large tidal volume (V(T)), with an unchanged end-tidal carbon dioxide partial pressure (P(ET)co(2)), could improve arterial carbon dioxide elimination, oxygen saturation (Spo(2)), and arterial blood oxygenation. DESIGN: Prospective, randomized, clinical study. SETTING: Single university hospital. PATIENTS: 60 ASA physical status I and II patients scheduled for elective urologic or general surgery. INTERVENTIONS: Patients were randomly assigned to one of two treatments: patients in group 1, nondead space (NDS), received a fresh gas flow of 1 L/min without added apparatus dead space volume. Patients in group 2, dead space (DS), received ventilation using an added dead space volume between the Y-piece and tracheal tube. In both groups, patients' lungs were ventilated to a fixed P(ET)co(2) value of 33.8 mmHg. Patients in the DS group were ventilated with V(T)s to maintain an airway plateau pressure (P(plateau)) of 0.04 cm H(2)O/kg over initial plateau pressure. The corrugated tube was then adjusted to maintain a fixed P(ET)co(2). MEASUREMENTS: Dead space volumes, P(ET)co(2), arterial CO(2) tension (Paco(2)), SpO(2), arterial O(2) tension (Pao(2)), V(T)s, and airway pressures were measured. MAIN RESULTS: Arterial CO(2) tension was significantly lower in the DS group, 36 +/- 2.3 mmHg, compared with the NDS group, 37.5 +/- 2.3 mmHg (P < 0.05), and the difference between P(ET)co(2) and Paco(2) was lower in the DS group than in the NDS group (P < 0.001). Oxygen saturation was 99% +/- 1.0% in the DS group compared with 98.5% +/- 1.5% in the NDS group (P < 0.05). Arterial O(2) tension was 13.2 +/- 25.5 mmHg in the DS group and 119.1 +/- 30.2 mmHg in NDS group (not significant). CONCLUSION: Larger V(T)s, with an unchanged P(ET)CO(2) concentration created by an added apparatus dead space volume, improved arterial carbon dioxide elimination.


Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Anesthesiology and Intensive Care
Original languageEnglish
Pages (from-to)170-174
JournalJournal of Clinical Anesthesia
Issue number3
Publication statusPublished - 2008
Publication categoryResearch

Related research output

Bruno Enekvist, 2011, Department of Anaesthesiology and Intensive Care, Lund. 76 p.

Research output: ThesisDoctoral Thesis (compilation)

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