Aprotinin reduces nitric oxide production in vitro and in vivo in a dose-dependent manner.

1. Cardiopulmonary bypass is associated with an increase in nitric oxide concentrations, and plasma levels of tumour necrosis factor and interleukin-1. Aprotinin, a serine protease inhibitor, commonly used during cardiopulmonary bypass to reduce blood loss, has been demonstrated to exhibit significant anti-inflammatory effects during and after cardiopulmonary bypass. 2. Airway nitric oxide was measured during cardiopulmonary bypass in 10 controls (Group 1), 10 subjects receiving half-dose aprotinin (Group 2) and 10 patients receiving full-dose aprotinin (Group 3). In vitro, a murine bronchial epithelial cell line (LA-4) was cultured with cytomix (a combination of tumour necrosis factor, interleukin-1, and (gamma-interferon) with and without aprotinin in increasing concentrations. Nitrite concentrations, the stable and measureable end-product of nitric oxide oxidative metabolism, were measured in the culture supernatant by chemiluminescence. 3. Airway nitric oxide concentrations were increased after 50 min cardiopulmonary bypass compared with that measured at 5 min in controls (53 +/- 5 versus 29 +/- 3 ppb, P < 0.05) but not in the aprotinin-treated groups (25 +/- 4 versus 14 +/- 5, Group 2; 21 +/- 6 versus 15 +/- 3 ppb, Group 3). 4. In a dose-dependent manner, nitrite levels (means +/- S.E.M.) were significantly reduced by aprotinin at 500 and 1000 units/ml when compared with cells cultured in the presence of cytomix alone (P < 0.05). 5. These data demonstrate that aprotinin, in a dose-responsive manner, reduces nitric oxide production in vivo and reduces cytokine-induced nitrite production by murine bronchial epithelial cells in vitro. Since increased airway nitric oxide is found in inflammatory lung diseases, like asthma, and anti-inflammatory therapy reduces the concentration of airway nitric oxide, these data support the concept that aprotinin is anti-inflammatory during cardiopulmonary bypass.

Diuretic-induced hypokalaemia inducing torsades de pointes.

Torsades de pointes (TP), an unique polymorphous type of ventricular tachycardia, is associated with either an acquired or congenitally prolonged QT interval. Several reports have demonstrated TP to follow an acquired prolonged QT interval secondary to chronic hypocalcaemia, hypomagnesaemia, or hypokalaemia. We report a rapid onset, acute extracellular hypokalaemia not associated with other electrolyte disturbances inducing a prolonged QT interval followed by TP. This is the first case report of a rapid onset isolated acute extracellular hypokalaemia inducing TP. Since anaesthetists are involved in therapies that will rapidly reduce extracellular potassium (diuretic, catecholamine, and/or insulin administration, hyperventilation), this cae report serves as a warning that such therapy may have the risk of arrhythmia induction.

Calcium channel blockade and uncontrolled blood pressure during phaeochromocytoma surgery.

Phaeochromocytoma has traditionally been managed by preoperative adrenergic blockade followed by surgical devascularization and excision. Recently, various studies have reported the use of calcium channel blocking drug therapy, either as monotherapy or in combination with other non-adrenergic blocking antihypertensive medications for blood pressure control in the preoperative management of phaeochromocytoma. In this case report, diltiazem as monotherapy was used to establish adequate preoperative blood pressure control in a patient with metastatic phaeochromocytoma to the liver. During cryoablation therapy surgery of the liver metastasis, the patient demonstrated extreme blood pressure lability requiring nitroprusside and high end tidal concentrations of isoflurane for blood pressure control. This case report suggests that during resection of a phaeochromocytoma where tumour devascularization is not obtainable, calcium channel blocking drugs as monotherapy may be inadequate to control blood pressure extremes. The authors suggest that under clinical circumstances reported above strong consideration be given to the use of standard adrenergic blocking drug therapy pre- and intraoperatively.

Fentanyl intermittent bolus technique for anesthesia in infants and children undergoing cardiac surgery.

The use of fentanyl by an incremental intravenous (IV) bolus technique was evaluated in eight pediatric patients (ages 4 months to 5 years, ASA III-IV) undergoing corrective surgery for congenital heart defects. Anesthesia was induced with 5 to 10 micrograms/kg of fentanyl. Additional boluses of comparable size were given intermittently thereafter, in order that a total dose of 100 micrograms/kg was achieved just before instituting cardiopulmonary bypass (CPB). Heart rate, systolic blood pressure, various measures of anesthetic depth, and plasma fentanyl levels measured by radioimmunoassay were compared at various points during anesthesia, surgery, and recovery. Decreases in heart rate were observed at the time of sternal incision and at 30 minutes thereafter, when doses of fentanyl were near-maximal. No changes from baseline in systolic blood pressure or in anesthetic depth occurred at any of the intervals studied. The plasma concentration of fentanyl was 30 +/- 8 ng/mL just after completion of the fentanyl administration, immediately before CPB. With onset of CPB, the fentanyl level fell to 13 +/- 9 ng/mL, a statistically significant difference from the baseline value. No further change occurred over the additional 231 +/- 74 minutes in the operating room. The fentanyl concentration was 10 +/- 4 ng/mL upon entry into the recovery room. It is concluded that administration of fentanyl in small, intermittent IV boluses, with dosing completed before the onset of CPB, produces satisfactory plasma levels, anesthesia, and hemodynamic stability in children undergoing corrective surgery for congenital cardiac defects.

Anesthesia for liver transplantation.

A successful liver transplant program needs cooperation and communication from the surgical, blood banking, pathology, primary care, and anesthesia services. Rapid availability of laboratory data, efficient blood banking services, ability to infuse blood products rapidly, coagulation management capability, and plentiful manpower are essential.

Management of hydrocephalus in ilio-omphalopagus conjoined twins.

One member of ilio-omphalopagus conjoined twins developed symptomatic hydrocephalus. Uneventful ventriculoperitoneal shunting improved the baby's condition. Technical aspects of the neurosurgical and anesthetic management in this case are discussed.

Serum concentrations of prostacyclin and thromboxane in children before, during, and after cardiopulmonary bypass.

Twenty-six consecutive pediatric patients undergoing reparative procedures necessitating cardiopulmonary bypass were prospectively studied to determine changes in serum levels of 6-keto-prostaglandin F1 alpha and thromboxane B2. Cardiac lesions included acyanotic lesions (five patients), obstructive lesions (10 patients), and right-to-left shunts (11 patients). There was a significant (p less than 0.05) increase in 6-keto-prostaglandin F1 alpha from preoperative levels measured at the time of arterial and venous cannula insertion. This concentration was maintained throughout cardiopulmonary bypass and remained significantly elevated (p less than 0.001) in the recovery room, but returned to preoperative levels by the morning after the operation. Preoperative levels of thromboxane B2 varied widely and were not significantly different from intraoperative levels. The postoperative levels of thromboxane B2, however, were significantly different (p less than 0.05) from the intraoperative levels. In the pediatric age group undergoing cardiopulmonary bypass, 6-keto-prostaglandin F1 alpha and thromboxane B2 change during bypass but do not significantly differ when preoperative levels are compared to postoperative values.

Potassium supplementation in ritodrine-induced hypokalemia.

Acute hypokalemia occurs during infusion of beta 2 agonists for tocolysis. This study examines the efficacy of supplemental potassium in treating this hypokalemia. Four groups of dogs were anesthetized and given lactated Ringer's solution (group I), potassium chloride (group II), ritodrine hydrochloride (group III), and ritodrine plus potassium (group IV). Arterial blood gases, pH, and serum and urinary electrolytes were measured. Results were analyzed by an analysis of variance. Serum potassium fell in groups I and III, rose in group II, and remained stable in group IV. Urinary potassium levels in groups that received ritodrine (III and IV) were not different from control levels. Potassium given with ritodrine will prevent hypokalemia. However, the risks of hyperkalemia exist if vigorous replacement is undertaken. There were no dysrhythmias and no adverse effects in any of the hypokalemic animals. Therefore, the routine administration of potassium is not advocated even in obstetric patients who undergo general anesthesia.

Serum potassium levels during and after terbutaline.

The intravenous infusion of terbutaline is associated with decreased levels of serum potassium. The duration of this hypokalemia has not been reported. Therefore, serum potassium levels were measured in dogs before during and for 3 hours after a 2-hour intravenous infusion of 0.5 micrograms/kg/min of terbutaline. Serum potassium levels decreased significantly during the infusion and returned to near preinfusion levels within 3 hours after the infusion was stopped. The mechanism for the decrease in the serum potassium is most likely a shift of the potassium ion from the extracellular space to the intracellular space.

Hypokalemia associated with terbutaline administration in obstetrical patients.

Chance observation of hypokalemia in a patient given intravenous terbutaline for management of premature labor led us to review retrospectively the medical records of all patients in whom terbutaline was similarly used as a tocolytic agent. All 18 patients in whom serum electrolyte levels were determined during terbutaline infusion had serum potassium levels less than 3.5 mEq/L. Although the duration of hypokalemia following the cessation of terbutaline infusion could not be retrospectively determined, collateral evidence suggests that serum potassium levels may return to normal range within approximately 30 minutes following discontinuation of the infusion of terbutaline. Serum levels of potassium during infusion of terbutaline could not be correlated in our 18 patients with either duration of infusion or amount of terbutaline infused, or with the amount of intravenous potassium that may have been simultaneously administered. Anesthesiologists should be aware that hypokalemia is associated with intravenous infusion of terbutaline as a tocolytic agent in the management of premature labor.

Hemorrhage and cardiac arrest during laparoscopic tubal ligation.

PIP: The article describes the case of a 38-year-old woman on whom laparoscopic tubal ligation was performed on an outpatient basis. During the procedure a 14 mm. tear was caused in the aorta, possibly by the Verres needle or the laparoscopic trocar, with subsequent hemorrhage and cardiac arrest. Similar cases are rarely reported in the literature. Still, it is important that facilities for massive transfusion should be available even in outpatient clinics.^ieng

Physostigmine reversal of diazepam-induced depression.

Diazepam is a valuable and widely-used adjunct to many inpatient and outpatient diagnostic and therapeutic procedures. However, the occasional and often unexpected delirium or coma induced by even modest doses of diazepam can be life threatening. Four cases are reported which demonstrate the prompt and effective reversal of diazepam-induced delirium and coma by the administration of physostigmine.