Anesthesia and analgesia
-
Anesthesia and analgesia · Aug 1993
Performance of pediatric resuscitation bags assessed with an infant lung simulator.
Many pediatric self-inflating bags are equipped with pressure relief (pop-off) valves to prevent barotrauma. We participated in a resuscitation in which a valve malfunction briefly caused inadequate ventilation. The pop-off valve was seated in an intermediate position between open and closed settings. ⋯ Inflation of all DMR (disposable) and PMR (nondisposable) bags in the intermediate valve position produced marked air leakage through the valve, with delivered tidal volumes of only 92 +/- 13 mL (DMR) for TI < 0.5 s, and unrecordable tidal volumes (< 50 mL) for both DMR and PMR self-inflating bags for TI > 0.6 s. A wide range of delivered tidal volumes was observed among all bags examined. We conclude that both DMR and PMR bags can be placed inadvertently in an intermediate valve position that can produce disastrous hypoventilation during resuscitation.(ABSTRACT TRUNCATED AT 250 WORDS)
-
Anesthesia and analgesia · Aug 1993
Randomized Controlled Trial Clinical TrialIntravenous lidocaine as a suppressant of coughing during tracheal intubation in elderly patients.
The effects of intravenously administered lidocaine on cough suppression in elderly patients over the age of 60 yr during tracheal intubation under general anesthesia were evaluated in two studies. In the first study, 100 patients received a placebo of either 0.5, 1.0, 1.5, or 2.0 mg/kg lidocaine intravenously 1 min before tracheal intubation. All visible coughs were classified as coughing. ⋯ The incidence of coughing decreased significantly (P < 0.01) when 2 mg/kg lidocaine was injected intravenously between 1 min and 3 min before attempting intubation. The cough reflex was almost entirely suppressed by plasma concentrations of lidocaine in excess of 4 micrograms/mL. The results suggest that intravenous administration of lidocaine is effective in suppressing the cough reflex during tracheal intubation in elderly patients under general anesthesia, but that relatively high plasma concentrations of lidocaine may be required for suppression of coughing.
-
Anesthesia and analgesia · Aug 1993
Randomized Controlled Trial Comparative Study Clinical TrialA clinical comparison of bronchial cuff pressures in three different designs of left double-lumen tubes.
This study compared the bronchial cuff pressures and volumes required by three different designs of disposable left double-lumen tubes during clinical one-lung ventilation in 48 patients having right thoracotomies. Mallinckrodt, Rusch, and Sheridan design tubes (n = 16 for each) were studied in a randomized fashion using Fr# 35, 37, 39, and 41 sizes (n = 12 for each size). ⋯ Intraoperatively, the Sheridan design required significantly higher mean bronchial cuff pressures: [27.9 cm H2O +/- 17 cm H2O (SD)] than either the Mallinckrodt [17.6 cm H2O +/- 8.5 cm H2O (P = 0.012)] or Rusch [14.1 cm H2O +/- 8.6 cm H2O (P = 0.010)] to achieve one-lung isolation. During prolonged one-lung ventilation, the potential for trauma to the bronchus may be reduced with a Mallinckrodt or Rusch design of left double-lumen tube.
-
To ascertain whether isoflurane produces a peripheral splanchnic sympathectomy as compared to fentanyl or pentobarbital anesthesia, 12 mongrel dogs (30-45 kg) were allocated randomly to one of three anesthetic test groups, tracheally intubated, surgically prepared, and subjected to unilateral electrical stimulation of the greater splanchnic nerve. Anesthetically, Group 1 animals (n = 4) received pentobarbital, Group 2 animals (n = 4) were administered fentanyl, and Group 3 animals (n = 4) received isoflurane. Stimulation continued for 90 min. ⋯ Arterial N and E concentrations remained unchanged. Results of Group 2 animals (fentanyl) were similar to those of Group 1; mean arterial blood pressure, pulmonary artery diastolic, and cardiac output increased (P < 0.005). Adrenal blood flow, adrenal vein N and E increased dramatically (P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)
-
Anesthesia and analgesia · Aug 1993
Comparative StudyEsmolol hydrochloride, sodium nitroprusside, and isoflurane differ in their ability to alter peripheral sympathetic responses.
To demonstrate that esmolol, sodium nitroprusside, and isoflurane differ in their abilities to alter adrenal medullary blood flow and other peripheral sympathetic responses to hypotension, 16 mongrel dogs anesthetized with pentobarbital were allocated randomly to one of four test groups and given two hypotensive stimuli, separated by 1 h, to a mean arterial blood pressure of 60 mm Hg for 10 min. The first stimulus, induced by blood loss into a pressurized bottle system, constituted the control for each animal. The second hypotensive stimulus was created by either repeat blood loss (Group 1), esmolol infusion (Group 2), sodium nitroprusside infusion (Group 3), or isoflurane administration (Group 4). ⋯ In fact, abdominal organ blood flow increased 2.5-fold (P < 0.001) during hypotension with SNP. Isoflurane 2%, 1.54 minimum alveolar anesthesia concentration (Group 4), abolished the increases in adrenal medullary blood flow, norepinephrine, and epinephrine observed during baseline hemorrhagic hypotension and attenuated the decrease in abdominal organ blood flow by 70% (P < 0.001). These data demonstrate that esmolol, sodium nitroprusside, and isoflurane differ radically in their ability to alter or blunt peripheral sympathetic responses to hypotension, and suggest that isoflurane is the drug most effective in blunting multiple responses of the peripheral sympathetic system.