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Biomedical subjects

J Sprung

Publications and source records attributed to J Sprung.

At least 37 records · Page 2Linked to original sources
PubMed1998

Flashback and nightmares after surgery under neuraxial anesthesia: a report of two cases.

Recall, awareness, flashback, and nightmares are reported complications of general anesthesia, but flashback and nightmares after regional anesthesia have not been described. Two patients underwent vascular and orthopedic surgery under spinal and epidural anesthesia, respectively. Local anesthetic consisted of bupivacaine, and sedation was achieved with the combination of fentanyl, midazolam, and diphenhydramine. In both patients the anesthetic course was uneventful, but the recovery process was complicated by flashbacks and nightmares leading to depression, physical complaints, and lengthy convalescence. Flashback and nightmares after neuraxial anesthesia are unreported and, therefore, their incidence is unknown.

Adjuvants, Anesthesia↗
PubMed1998

Perioperative cardiovascular morbidity in patients with coronary artery disease undergoing vascular surgery after percutaneous transluminal coronary angioplasty.

OBJECTIVE: Patients with coronary artery disease (CAD) who undergo noncardiac surgery are at increased risk for perioperative myocardial infarction (PMI). Undergoing successful coronary artery bypass grafting (CABG) before such surgery has been shown to decrease perioperative cardiac morbidity and mortality. Percutaneous transluminal coronary angioplasty (PTCA) is an alternative treatment for these patients. Perioperative cardiac morbidity in patients with CAD who underwent PTCA before their vascular surgery was reviewed. SETTING: A tertiary care referral center for patients with cardiovascular heart disease. PARTICIPANTS: Review of vascular surgery database for patients who underwent vascular surgery preceded by PTCA between 1984 and 1995. Patients were excluded if they had a history of CABG within 2 years of surgery, had PTCA more than 18 months before surgery, or had incomplete data. MEASUREMENTS: Data were collected concerning cardiac history, left ventricular (LV) function, perioperative cardiac morbidity (angina, MI, congestive heart failure [CHF], and arrhythmias). MAIN RESULTS: Of 194 patients who underwent aortic abdominal surgery, carotid endarterectomy (CEA), or peripheral vascular surgery preceded by PTCA, 104 (54%) had a previous MI. Twenty-six patients (13.4%) had perioperative cardiac morbidity. Only one patient had an MI (0.5%; 95% confidence interval [CI], 0.0 to 2.8), whereas one patient died of CHF followed by multisystem organ failure (0.5%). The median interval between PTCA and surgery was 11 days (interquartile range, [IQR] 3 to 49 days). Patients who developed perioperative cardiac morbidity were older than those who did not (p = 0.02). Patients who had a history of CABG (before PTCA) had a higher incidence of postoperative angina (p = 0.04). The degree of preoperative LV dysfunction was linearly related to the incidence of new postoperative CHF (p = 0.01). Arrhythmias were more common in patients undergoing abdominal vascular surgery (17.9%) than in those undergoing CEA (2.5%; p = 0.03) or peripheral vascular surgery (5.2%; p = 0.02). CONCLUSION: High-risk cardiac patients undergoing vascular surgery who have had PTCA performed up to 18 months preoperatively have a low incidence of perioperative cardiac morbidity. Prophylactic PTCA may be beneficial in patients with CAD who are at high risk for perioperative cardiac complications.

Aged↗
PubMed1998

Ischemic liver dysfunction after elective repair of infrarenal aortic aneurysm: incidence and outcome.

OBJECTIVE: To assess the frequency of early postoperative liver dysfunction in patients undergoing elective infrarenal aortic aneurysm repair, their hospital course, and outcome. DESIGN: A retrospective case-control study. SETTING: A single tertiary referral center. PARTICIPANTS: A review of medical records of 942 consecutive asymptomatic patients with normal preoperative liver function test results who had elective infrarenal aortic aneurysm repair with infrarenal aortic cross-clamping. The authors selected all patients who had an acute increase in serum hepatic enzyme levels (minimum fivefold increase in aspartate aminotransferase [AST] and twofold increase in lactate dehydrogenase [LDH] levels) within the first 7 perioperative days (study patients). The control group consisted of 42 patients with normal postoperative liver function test results, matched by age, sex, and year of surgery to study patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Aortic cross-clamping times, lowest intraoperative blood pressure, duration of hypotension (systolic blood pressure < or = 95 mmHg), lowest intraoperative base deficit, and estimated blood loss were compared between control and study patients. The study also analyzed perioperative metabolic, hemostatic, hepatic, and renal function variables; the intraoperative course; postoperative complications; and inhospital outcome. Fourteen of 942 patients (1.5%) comprised a study group. In 11 patients (1.2%), AST and LDH levels moderately increased, and three patients (0.3%) developed changes consistent with a diagnosis of acute ischemic hepatitis (AIH). In all patients, the serum liver enzyme levels peaked between 24 and 72 postoperative hours. Three patients with AIH developed concomitant acute renal failure; one had associated disseminated intravascular coagulation (DIC) and died. Of 11 patients with moderate increases, one subsequently developed multisystem organ failure and died. The overall in-hospital mortality rate for patients with postoperative liver dysfunction was 14% (2/14) and for the control group it was 2.3% (1/42). The duration of hypotension and metabolic acidosis were more pronounced in patients who postoperatively developed liver dysfunction (both p < 0.001); however, study and control patients did not differ in the duration of aortic cross-clamping, lowest intraoperative blood pressure, or estimated blood loss. CONCLUSION: Liver enzyme levels acutely increased in 1.5% of patients after elective infrarenal aortic aneurysm repair with infrarenal cross-clamping. In patients with moderately elevated serum liver enzyme levels, postoperative recovery was relatively uncomplicated, whereas all three patients with AIH developed acute renal failure and had a more complicated postoperative course. Those with postoperative liver dysfunction had a longer duration of intraoperative hypotension and more pronounced metabolic acidosis.

Aged↗
PubMed1998

Effects of ketamine on the contractility of failing and nonfailing human heart muscles in vitro.

BACKGROUND: Induction of anesthesia with ketamine may decrease cardiac output in critically ill patients. The direct effects of ketamine on the failing human myocardium are unknown. This study examined the effects of ketamine on contractility of human failing and nonfailing myocardium in vitro. METHODS: Trabecular muscles were obtained from the left ventricles and right atria of 10 patients with heart failure undergoing transplantation and from the right atria of 14 patients undergoing coronary artery bypass surgery. Muscles were dissected and mounted in a 37 degrees C bath and stimulated at 1 Hz. Isometric contraction variables were recorded before and after addition of ketamine (concentrations between 0.44 and 440.0 microM) to the bath. The effects of ketamine were compared with those of buffer. To test muscle contractility, at the end of each experiment, 1 microM isoproterenol was added. RESULTS: Ketamine caused a significant dose-dependent decrease in developed tension in nonfailing atrial and failing atrial and ventricular muscles (P < 0.01 for all). In vehicle-treated muscles, developed tension remained stable, and isoproterenol increased developed tension 136% (nonfailing atrial muscles) and 178% (failing atrial and ventricular muscles; P < 0.01). In nonfailing atrial muscle, isoproterenol restored the ketamine-induced decrease in developed tension toward the baseline value. In failing atrial and ventricular muscles exposed to ketamine, isoproterenol did not counteract the ketamine. CONCLUSIONS: Ketamine exerts a direct dose-dependent negative inotropic effect in human heart muscles. The failing myocardium exposed to ketamine has reduced ability to increase contractility even in the presence of increased beta-adrenergic stimulation.

Adult↗
PubMed1997

Effects of gas flow management on postintubation end-tidal anesthetic concentration and operating room pollution.

STUDY OBJECTIVE: To study how different anesthetic practices during the transition from anesthetic delivery by mask to endotracheal intubation affect end-tidal postintubation anesthetic concentration and operating room (OR) pollution. DESIGN: Prospective study. SETTING: Anesthesia research laboratory. MEASUREMENTS AND MAIN RESULTS: We studied four gas flow management practices: practice vaporizer off, only the anesthetic vaporizer was turned off; all off, oxygen (O2), nitrous oxide (N2O), and the vaporizer were turned off; gas off: O2 and N2O were turned off; and all on: neither the gas flows nor the vaporizer were turned off. A model of inhalational anesthetic induction was simulated by using an adult circle system attached to a reservoir bag ("artificial lung"). By using a fixed gas flow, we achieved an end-tidal N2O (ETN2O) concentration of 70% and end-tidal halothane (ETHal) concentration of 3%, then stopped mechanical ventilation and performed the four practices for a 30-second "intubation" period. During this time, the reservoir bag was disconnected from the circuit, and the gas volume exiting the circuit (pollution volume) was measured. After this 30-second disconnect period, the bag was reconnected to the anesthetic circuit, and the original ventilation, gas flows, and vaporizer setting were resumed. The anesthetic concentrations were measured at 10, 20, and 30 seconds after reconnection. For the vaporizer off practice, ETHal was low and did not return to equilibrium within 30 seconds (p < 0.05); ETN2O clinically was unaltered. In the all off practice, anesthetic concentrations were below equilibrium at 10, 20, and 30 seconds (p < 0.05). For the gas off practice, ETHal was slightly below equilibrium at all times; ETN2O was below equilibrium at 10, 20, and 30 seconds (p < 0.05). In the all on practice, end-tidal anesthetic concentrations were unchanged when compared with equilibrium (p > 0.05). Pollution volumes in the vaporizer off and all on practices were ten-fold higher than in the all off and gas off practices (p < 0.05). CONCLUSION: In a mechanical model of anesthetic induction, turning the gas flows off before "intubation" and leaving the vaporizer on (the gas off practice) maintained "postintubation" end-tidal drug concentrations close to "preintubation" equilibrium and minimized OR pollution.

Air Pollution, Indoor↗
PubMed1997

Lung mechanical behavior during one-lung ventilation.

OBJECTIVE: Switching from two-lung to one-lung ventilation would be expected to have large effects on lung mechanical properties, and these effects may depend on tidal volume and respiratory frequency. These changes in lung mechanics with one-lung ventilation may be similar to pulmonary edema. Deteriorating lung mechanics during pulmonary edema have been attributed to a loss of ventilated lung units. Therefore, changes in lung mechanics caused by one-lung ventilation were measured and compared with those previously seen during pulmonary edema. DESIGN: Prospective study. SETTING: Research laboratory. INTERVENTIONS: After induction of anesthesia, beagle dogs' tracheas were intubated with an endotracheal tube with a bronchial blocker (Univent System Corp, Tokyo, Japan) to apply one-lung ventilation. The proper position of the bronchial blocker during one-lung ventilation was confirmed with a fiberoptic bronchoscope. MEASUREMENTS AND MAIN RESULTS: Lung elastance (EL) and resistance (RL) were calculated from measurements of airway pressure, esophageal pressure, and airway flow in five anesthetized, paralyzed dogs during sinusoidal forcing at a constant mean airway pressure of 10 cmH2O in a wide range of breathing frequencies (0.2 to 1.0 Hz in intervals of 0.2) and tidal volumes (50, 100, 200, and to 300 mL). Measurements were made before and after the left mainstem bronchus was occluded with the bronchial blocker. During ventilation of both lungs, EL and RL depended relatively little on frequency, and both EL and RL were independent of tidal volume. During one-lung ventilation, EL doubled and, at most frequencies, RL increased; frequency dependences were not increased, and no dependence on tidal volume was observed. CONCLUSIONS: The lack of tidal volume dependence in EL and lack of large-frequency dependence in RL during one-lung ventilation are inconsistent with changes induced by severe pulmonary edema. Although decreases in ventilatable lung volume may contribute to increases in lung elastance, other characteristics of mechanical behavior during one-lung ventilation differ from those of pulmonary edema; therefore, other additional mechanisms must be involved in determining lung mechanical properties during severe pulmonary edema.

Airway Resistance↗
PubMed1997

Chest wall and lung mechanics during acute hemorrhage in anesthetized dogs.

OBJECTIVES: In trauma and in surgical patients, respiratory mechanics may change because of many factors, including the hypotension induced by hemorrhage. The effects of acute hemorrhage on elastic and resistive characteristics of the respiratory system were studied. DESIGN: Prospective study. SETTING: Anesthesia research laboratory. INTERVENTIONS: Acute hemorrhagic shock was induced in 24 supine anesthetized/paralyzed, mechanically ventilated dogs by blood withdrawal over a 12-minute period to decrease systolic arterial pressure to 50 mmHg; additional blood was subsequently withdrawn to maintain this pressure for 2 hours. Total respiratory system dynamic compliance and resistance and lung and chest wall compliances and resistances were measured. MEASUREMENTS AND MAIN RESULTS: Total respiratory system dynamic compliance decreased from control (0.03 +/- 0.002 L/cmH2O) by the first 10 minutes of shock (p < 0.05) and was 9.8 +/- 2% lower than control 2 hours after the induction of shock because of decreases in both lung (9.6 +/- 3%) and chest wall (7.7 +/- 3%) compliances. Total respiratory resistance increased 12.8 +/- 3% from control (3.08 +/- 0.19 cmH2O/L/s) after 2 hours of shock (p < 0.05) because of an increase in chest wall resistance (21.6 +/- 8%, p < 0.05). Pulmonary resistance was not significantly increased (p > 0.05). In six control dogs, prepared similarly but not hemorrhaged, chest wall compliance and resistance did not change, but lung compliance gradually decreased by 17.8% during 150 minutes of anesthesia/paralysis. Lung resistance increased only after 100 minutes (p < 0.05). CONCLUSIONS: (1) Hemorrhagic shock caused slight changes in the chest wall, but effects on lung mechanics were a consequence of prolonged mechanical ventilation during anesthesia/paralysis, and (2) changes in respiratory mechanics caused by hemorrhagic shock are small and, unless other deleterious factors are present, would probably have little clinical significance.

Acute Disease↗