Use of end-tidal partial pressure of carbon dioxide to predict arterial partial pressure of carbon dioxide in harp seals during isoflurane-induced anesthesia

Introduction: Despite several advantages over endotracheal tube (ETT), laryngeal mask airway (LMA), which is used in emergencies under difficult airway maintenance conditions, is rarely utilized in prolonged surgery. We compared the variables representing intraoperative gas exchange with second-generation LMA and ETT during prolonged laparoscopic abdominal surgery. Methods: Prolonged surgery was defined as a surgery lasting more than 2 h. In total, 394 patients who underwent laparoscopic liver resection via either second-generation LMA or ETT were retrospectively analysed. Parameters including end-tidal pressure of carbon dioxide (ETCO2), tidal volume (TV), respiratory rate (RR), peak inspiratory pressure (PIP), arterial partial pressure of carbon dioxide (PaCO2), pH, and ratio of arterial partial pressure of oxygen to fractional inspired oxygen (PFR) during surgery were compared between the two groups. In addition, the incidence of postoperative pulmonary complications (PPC) including pulmonary aspiration was also compared. Results: The values of ETCO2, TV, RR and PIP during pneumoperitoneum were comparable between the two groups. Although PaCO2 at 2 h after induction was higher in patients with LMA (40.5 vs. 38.5 mmHg, p < 0.001), the pH and PFR values of the two groups were comparable. The incidence of PPC was not different. Conclusion: During prolonged laparoscopic abdominal surgery, the second-generation LMA facilitates adequate intraoperative gas exchange and represents an alternative to ETT.

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Targeting Arterial Partial Pressure of Carbon Dioxide in Acute Respiratory Distress Syndrome Patients using Extracorporeal Carbon Dioxide Removal

Artificial Organs ◽

10.1111/aor.14127 ◽

2021 ◽

Author(s):

John K. Leypoldt ◽

Jörg Kurz ◽

Jorge Echeverri ◽

Markus Storr ◽

Kai Harenski

Keyword(s):

Carbon Dioxide ◽

Acute Respiratory Distress Syndrome ◽

Respiratory Distress Syndrome ◽

Respiratory Distress ◽

Partial Pressure ◽

Distress Syndrome ◽

Carbon Dioxide Removal ◽

Extracorporeal Carbon Dioxide Removal ◽

Arterial Partial Pressure

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Expiratory and arterial partial pressure relations under different ventilation-perfusion conditions

Journal of Applied Physiology ◽

10.1152/jappl.1983.54.6.1745 ◽

1983 ◽

Vol 54 (6) ◽

pp. 1745-1753 ◽

Cited By ~ 6

Author(s):

A. Zwart ◽

S. C. Luijendijk ◽

W. R. de Vries

Keyword(s):

Partial Pressure ◽

Dead Space ◽

Gas Analysis ◽

Lung Model ◽

Breathing Patterns ◽

Tracer Gas ◽

Physiological Dead Space ◽

Arterial Partial Pressure ◽

The Difference ◽

End Tidal

Inert tracer gas exchange across the human respiratory system is simulated in an asymmetric lung model for different oscillatory breathing patterns. The momentary volume-averaged alveolar partial pressure (PA), the expiratory partial pressure (PE), the mixed expiratory partial pressure (PE), the end-tidal partial pressure (PET), and the mean arterial partial pressure (Pa), are calculated as functions of the blood-gas partition coefficient (lambda) and the diffusion coefficient (D) of the tracer gas. The lambda values vary from 0.01 to 330.0 inclusive, and four values of D are used (0.5, 0.22, 0.1, and 0.01). Three ventilation-perfusion conditions corresponding to rest and mild and moderate exercise are simulated. Under simulated exercise conditions, we compute a reversed difference between PET and Pa compared with the rest condition. This reversal is directly reflected in the relation between the physiological dead space fraction (1--PE/Pa) and the Bohr dead space fraction (1--PE/PET). It is argued that the difference (PET--Pa) depends on the lambda of the tracer gas, the buffering capacity of lung tissue, and the stratification caused by diffusion-limited gas transport in the gas phase. Finally some determinants for the reversed difference (PET--Pa) and the significance for conventional gas analysis are discussed.

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