A 1100-g, 10-day-old infant is to undergo ligation of a patent ductus arteriosus after unsuccessful medical treatment. Within three minutes of intravenous administration of atropine 20 mcg, fentanyl 20 mcg, and pancuronium 0.1 mg, systemic blood pressure decreases from 80 to 30 mmHg, heart rate from 180 to 140 bpm, and arterial oxygen saturation from 90% to 80%. The most appropriate management is to
(D) Inhibiting sodium ion influx across the neuronal cell membrane
(E) Opening sodium channels at the nodes of Ranvier
D
A combined epidural and general anesthetic is used for aortofemoral bypass surgery. Just prior to extubation, the patient received morphine 5 mg through the epidural catheter. Eleven hours later, he is unresponsive while breathing 40% oxygen from a face mask. Respiratory rate is 6/min and SpO2 is 92%. Arterial blood gas analysis shows PaO2 80 mmHg, PaCO2 84 mmHg, and pH 7.16. Which of the following statements concerning this patient is true?
(A) Hypercarbia is contributing to the decreased level of consciousness
(B) Naloxone is ineffective for reversing the respiratory depression
(C) The oxygen saturation is higher than expected because of the pH
(D) The risk for respiratory depression would have been lower with subarachnoid administration of 0.5 mg morphine
(E) Residual local anesthetic is contributing to the respiratory depression
A 30-kg patient with asthma is receiving general anesthesia and being mechanically ventilated with a measured tidal volume of 300 mL. Increasing the fresh gas flow from 3 L/min to 9 L/min without changing the ventilatory rate or I:E ratio will result in
A patient receives remifentanil 25 mcg just before retrobulbar block with 0.25% bupivacaine 4 mL. Over the next 10 minutes, he develops apnea and loses consciousness. Which of the following is the most likely explanation?
(A) Effects of remifentanil
(B) Injection of local anesthetic into cerebrospinal fluid