Simin Saatee

Canister tip orientation and residual volume have significant impact on the dose of benzocaine delivered by hurricaine® spray

Delivered quantities of 20% benzocaine spray (Hurricaine; Beutlich L.P. Pharmaceuticals, Waukegan, IL) are estimated by counting the number of sprays or the spraying time. Because Hurricaine spray supplies a continuous (albeit nonmetered) stream of benzocaine, neither method addresses delivered dose. We hypothesized that dose per time is a function of canister content and orientation. Thirty full canisters of Hurricaine were placed into three equal orientations (upright, inverted, or horizontal). Extrapolating from a full canister, four different estimates of benzocaine residual volume were determined before spraying out the contents (80%, 60%, 40%, and 20% full). Each canister was then sprayed for 10-s intervals, and the quantity delivered was calculated and compared statistically. Upright canisters 100% full emitted more benzocaine than canisters with residual volume 20% full (190 +/- 10 vs 172 +/- 10 mg/s). Inverted canisters emitted significantly less benzocaine from 100% full to residual volume 20% full (188 +/- 14 vs 70 +/- 10 mg/s). Oriented horizontally, two full canisters emitted <76 mg/s benzocaine, contrasted with the remaining eight in that group (186 +/- 20 mg/s). We conclude that the benzocaine (Hurricaine) sprayed in milligrams per second depends on canister content and orientation. When residual volumes diminish, there is a reduction in spraying volume per time. This diminution occurs progressively from larger to smaller residual volumes with canisters oriented horizontally, inverted, or upright. Arbitrary documentation of spraying time bears no relationship to dose delivered. Perhaps affixing an atomization device to a graduated syringe filled with benzocaine will help increase accuracy and precision in dosing.

Inadvertent misconnection of the scavenger hose: A cause for increased pressure in the breathing circuit.

74:1166–70 5. Gammie JS, Zenati M, Kormos RL, Hatter BG, Wei LM, Pellegrini RV, Griffith BP, Dyke CM: Abciximab and excessive bleeding in patients undergoing emergency cardiac operations. Ann Thor Surg 1998; 65:465–9 6. Despotis GJ, Levine V, Filos KS, Joiner-Maier D, Joist, JH: Hemofiltration during cardiopulmonary bypass: the effect of anti-Xa and anti-IIa heparin activity. Anesth Analg 1997; 84:479–83

Succinylcholine Cannot Relieve an Airway Obstruction Caused by Pharyngeal and Laryngeal Edema

In their case report, Ibarra et al. (1) describe a patient with pharyngeal and laryngeal edema that they attribute to traumatic asphyxia. Although we agree that traumatic asphyxia may change the structural contour of upper airway, we disagree with the authors on three issues. First, the authors elected to induce their patient with class IV Mallampati airway using succinylcholine and thiopental when airway obstruction developed after failed attempts at direct awake laryngoscopy. Although the authors report resolution of airway obstruction and achievement of good ventilation after the administration of IV anesthesia, yet this technique is not at all the best approach for securing an obstructed airway. Succinylcholine cannot relieve an airway obstruction if, indeed, it was caused by pharyngeal and laryngeal edema. If the ventilation and visualization of the larynx were satisfactory after the induction of anesthesia, why did the tracheal intubation attempt fail and immediate cricothyroidotomy become necessary? Second, the report of arterial blood gas result is incorrect. The Henderson-Hasselbalch equation for bicarbonate buffer system may be used to exclude the possibility of an incorrect blood gas report. According to this equation, it is impossible to have a pH, of 7.24, Pace, of 24 mm Hg, and HCO,of 15.8 mEq/L. For the pH, to be 7.24, either the bicarbonate should be lower (9.93 mEq/L), the Pace, should be higher (38.16 mm Hg), or both. Third, the authors fail to explain their rationale for the transfusion of 8 U of packed red blood cells, 8 U of fresh-frozen plasma, 5 U of platelets, and 2 L of lactated Ringer’s solution. A decreasing hemoglobin level (from 10.5 to 8 g/dL) and hypotension do not constitute adequate indication for this massive transfusion of blood products.