Nomogram for Anaesthetic Uptake

Minimal-flow anaesthesia with controlled ventilation: comparison between laryngeal mask airway and endotracheal tube

“…The uptake (in mL min −1 ) of oxygen was calculated using Brody’s formula [7], N 2 O uptake was calculated using Beatty’s formula [8–10], and isoflurane uptake calculated using the formula of Lowe [11,12]. The theoretical uptake of O 2 , N 2 O and isoflurane is calculated at different time points (Table 1).…”

“… Uptake of volatile anaesthetics during anaesthesia – detection of leakage (a) Uptake (in mL min −1 ) of oxygen (calculated using Brody’s formula [7], solid line), N 2 O (calculated using Beatty’s formula [8,9,10], short dashed line), isoflurane (calculated using the Lowe’s formula [11,12,17], dotted line) and the total gas uptake (long dashed line) over time (calculations are performed for a 30%:70% N 2 O mixture, MAC for isoflurane 1.8 and blood gas partition coefficient for isoflurane of 1.4). (b) Calculated filling status of the reservoir bag in a 70‐kg patient.…”

A simple method for evaluation of the uptake of isoflurane and its comparison with the square root of time model

“…Isoflurane uptake was based on oxygen requirement, which were derived from nomograms (Appendix). [11] The decreased requirement under anaesthesia was taken care of by further decrease in FGF progressively to metabolic flows. Isoflurane infusion was not connected to the inspiratory limb to avoid any accidental exposure of liquid isoflurane to patient's airway.…”

“…[9] Subsequently, a series of dosage tables according to patient's body habitus have been predicted for use during closed circuit anaesthesia. [1011] The derivations of these complex formulae and mathematical models have deterred anaesthesiologists from using low flow anaesthesia. The anaesthesiologist is more interested in attaining a desired minimum alveolar concentration (MAC) as the parameter and not the pharmacokinetics of the agent.…”

Closed system anaesthesia in dogs using liquid sevoflurane injection; evaluation of the square-root-of-time model and the influence of CO2 absorbent

“…In preliminary trials, an end‐tidal concentration of 2.6% (1.1 × MAC) was found to produce suitable conditions – in conjunction with extradural anaesthesia – for pelvic limb orthopaedic procedures lasting 2 hours. The value of λ B/G was estimated to be 0.68 (Strum & Eger 1987) and cardiac output was calculated as 2 × kg 0.75 dL minute −1 (Lowe & Viljoen 1994). In the current study the value for cardiac output used in was 0.8 × 2 × kg 0.75 dL minute −1 .…”