Biomedical subjects
R K Stoelting
Publications and source records attributed to R K Stoelting.
The 29th Rovenstine lecture: clinical challenges for the anesthesiologist.
In conclusion, I hope that my comments have reaffirmed your biases or, even more importantly, stimulated you to think in a different way about the information explosion in our specialty and medicine in general. I believe our specialty is in a golden era that will benefit from the past and be nourished by new discoveries and understanding. We as clinicians must accept the challenge of recognizing what new information deserves incorporation into our practice, what old information deserves to be sustained, and what merits new scrutiny and perhaps should be discarded. If I had one wish, it would be that anesthesiologists would never lose their zeal to be students--their thirst for new information--as the continuum of anesthesia education is indeed a life-long process. That wish, ladies and gentlemen, is my challenge to all anesthesiologists.
Intraoperative pulmonary edema in a patient being treated with amiodarone.
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Hemodynamic effects of mivacurium chloride administered to patients during oxygen-sufentanil anesthesia for coronary artery bypass grafting or valve replacement.
The hemodynamic effects of mivacurium chloride were studied in 54 adult cardiac patients anesthetized with midazolam and sufentanil. After baseline data were collected, a placebo (N = 9) or mivacurium was administered over 60 seconds, the latter in doses of 0.15 (N = 18), 0.20 (N = 18), or 0.25 (N = 9) mg/kg. Measurements were repeated 2, 5, and 10 minutes later. Baseline measurements were similar. A slight decrease in heart rate over time reached statistical significance in several groups including the control group. Mean arterial, mean pulmonary arterial, pulmonary arterial occlusion, and right atrial pressures and cardiac output did not change, nor did systemic and pulmonary vascular resistances and cardiac index. Besides the decrease in heart rate, the only hemodynamic change to reach statistical significance was an increase in stroke volume in patients given mivacurium 0.25 mg/kg. Significant hypotension occurred in two patients; in one, a sudden decrease in mean arterial pressure of 24% occurred 1 minute after mivacurium 0.20 mg/kg. Blood pressure was restored by ephedrine 10 mg. In the other patient, given mivacurium 0.25 mg/kg, mean arterial pressure decreased 50% from 73 to 37 mm Hg. Recovery was rapid without treatment. It is concluded that mivacurium administered in doses of 0.15 to 0.25 mg/kg over 60 seconds to cardiac patients is associated with few significant hemodynamic effects. However, a small number of patients may experience significant transient hypotension when given doses greater than of 0.15 mg/kg, two times the ED95.
Intrathecal morphine--an underused combination for postoperative pain management.
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Hemodynamic effects of doxacurium chloride in patients receiving oxygen sufentanil anesthesia for coronary artery bypass grafting or valve replacement.
Doxacurium chloride is an investigational long-acting neuromuscular blocking drug, which has been shown to be devoid of cardiovascular side effects when administered in modest doses to healthy patients. This is the first hemodynamic study of doxacurium in adult patients with cardiac disease. Forty-one patients scheduled to undergo cardiac surgery were studied. Anesthesia consisted of induction with midazolam 0.2-0.3 mg/kg and sufentanil 0.01-0.03 mg followed by an infusion of sufentanil at 0.03-0.06 mg.min-1. Baseline hemodynamic data were collected during a stable state of sufentanil anesthesia. Doxacurium was then administered in doses of 1, 2, or 3 times its ED95 of 0.025 mg/kg. Hemodynamic measurements were repeated at 2, 5, and 10 min after doxacurium injection in the absence of surgical stimulation. An additional group of control patients received saline instead of doxacurium. Baseline hemodynamic measurements were similar among groups. There was a slight decrease in heart rate in all groups over time. However, there was no significant difference between the groups of patients receiving doxacurium and the control group in which the heart rate decreased progressively from 52 beats/min at baseline to 49 beats/min 10 min after doxacurium administration. At no time was there any significant change in mean arterial pressure, right atrial pressure, or cardiac output. Likewise derived hemodynamic variables including cardiac index, stroke volume, and pulmonary vascular resistance were unchanged. In addition to the decrease in heart rate, the hemodynamic changes, which reached statistical significance, were clinically insignificant and occurred predominantly in the group of patients receiving doxacurium 0.08 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)
Effects of hypothermia on brainstem auditory evoked potentials in humans.
Ten adult patients who underwent open heart surgery under induced hypothermia had brainstem auditory evoked potentials (BAEPs) recorded at 1 degree- to 2 degrees C-steps as body temperature was lowered from 36 degrees C to 20 degrees C to determine temperature-dependent changes. Hypothermia produced increased latencies of BAEP waves I, III, and V; the prolongation was more severe for the later components with the result that interpeak latencies I-III, III-V, and I-V were also prolonged. The temperature-latency relationship was nonlinear and best expressed by exponential curve. The latencies of waves I, III, V and the interpeak latency I-V increased roughly 7% for each 1 degree C drop; they doubled at a temperature around 26 degrees C. The amplitude of the BAEP components had a quasiparabolic relationship to temperature; the amplitude rose with hypothermia to 28 degrees or 27 degrees C, but decreased linearly with further cooling. All BAEP components were present at temperatures above 23 degrees C and absent below 20 degrees C. With rewarming, the changes reversed and BAEPs returned to initial prehypothermia status.
Isoflurane and postoperative hepatic dysfunction.
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Hepatic dysfunction after isoflurane anesthesia.
Four members of the Anesthetic and Life Support Advisory Committee of the Food and Drug Administration assessed the contribution of isoflurane (Forane) to 45 instances of hepatic dysfunction after isoflurane anesthesia reported to the FDA for 1981-1984. For 29 (64%) of the cases, at least three members concluded that nonanesthetic causes (e.g., hypoxia, sepsis, viral infection) explained the hepatic injury. For 16 cases (36%), two or more members concluded that isoflurane might be one of several possible causes of the hepatic injury. In the latter cases, patients tended to be younger, had undergone anesthesia of shorter duration for operations outside the chest and abdomen, had developed symptoms later, had higher plasma transaminase values but lower bilirubin values, and had a lower incidence of eosinophilia, anemia, transfusions, and congestive heart failure. The committee concluded that current evidence does not indicate a reasonable likelihood of an association between the use of isoflurane and the occurrence of postoperative hepatic dysfunction.
Haemodynamic effects of atracurium in the presence of potent inhalation agents.
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Current views on the role of opioid receptors and endorphins in anesthesiology.
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Haemodynamic changes and circulating histamine concentrations following protamine administration to patients and dogs.
Haemodynamic changes and the circulating concentrations of histamine associated with the intravenous infusion of protamine were measured in six adult patients undergoing elective aortocoronary bypass graft surgery and twelve halothane-anaesthetized dogs. Administration of protamine (4.7 mg X kg-1) over five minutes to patients at the conclusion of cardiopulmonary bypass did not produce haemodynamic changes or alterations in the arterial or mixed venous concentrations of histamine. Likewise, the administration of protamine (4.5 mg X kg-1) over five minutes to six dogs produced no haemodynamic changes or alterations in the arterial concentrations of histamine. Conversely, administration of protamine (4.5 mg X kg-1) as a rapid intravenous injection to six other dogs produced a decrease (about 30 per cent below control) in systolic, diastolic and mean arterial pressure (p less than 0.05) at 2.5 minutes following the injection. These decreases in blood pressure were paralleled by increases in the arterial concentration of histamine from 295 +/- 71 pg X ml-1 (mean +/- SD) before protamine to 860 +/- 6,465 pg X ml-1 (p less than 0.05) 2.5 minutes after protamine. Haemodynamic changes and the arterial concentration of histamine were not different from control five minutes after protamine administration. It is concluded that administration of protamine over five minutes to patients or dogs does not evoke significant haemodynamic changes or alterations in circulating concentrations of histamine. Conversely, rapid injection of protamine to dogs evokes transient decreases in blood pressure that are paralleled by increases in the arterial concentrations of histamine.
Monitoring of multimodality evoked potentials during open heart surgery under hypothermia.
Multimodality evoked responses (ERs) were monitored in 16 adults who had cardiac surgery under cardiopulmonary bypass and moderate hypothermia (19-25 degrees C). Cooling affected all sensory ERs by progressively increasing the latencies of the major components. The effect was more profound on the later than on the earlier ER components. Visual evoked responses (VERs) were most inconsistent and always disappeared at temperatures below 25 degrees C. The later components of the long latency somatosensory evoked responses (SERs) also attenuated or disappeared rather early during hypothermia. On the other hand, short latency SERs were more resistant to the effects of hypothermia. They were always recordable at temperatures of 25 degrees C or above; and usually persisted even at temperatures between 20 and 25 degrees C. Brain-stem auditory evoked responses (BAERs) were consistently present at temperatures above 25 degrees C, wave V was recordable in majority between 20 and 25 degrees C. All sensory ERs disappeared with severe hypothermia (20 degrees C or less) except the components generated more peripherally such as N10 of the short latency SERs. We feel that BAERs and short latency SERs may serve as useful intraoperative monitors of brain function during hypothermia.
Exaggerated increase in serum potassium following succinylcholine in dogs with beta blockade.
The authors tested in dogs the hypothesis that beta-adrenoceptor blockade might alter the time course or magnitude of serum potassium (K+) changes following the administration of succinylcholine (SCh). The results indicate that the normal increase in K+ induced by SCh (1 mg/kg intravenously) is exaggerated in the presence of propranolol-induced (0.25 mg/kg), beta-adrenoceptor blockade. Specifically, a peak increase of 1.7 mEq/1 (43%) over control K+ was noted in the beta-blocked dogs versus a 0.5 mEq/1 (13%) increase in control dogs. The peak increase in K+ occurred later in the beta-blocked dogs (60-90 min post-SCh) versus control dogs (30 min post-SCh). The authors postulate that these results reflect impairment of intracellular uptake of the SCh-induced acute K+ load secondary to beta-adrenoceptor blockade. Additionally, in a third group of dogs, diazepam in a dose of 0.5 mg/kg attenuated the K+ increases (1 mEq/1-24%) following SCh in beta-blocked dogs. Whether these data can be extrapolated to beta-adrenoceptor blocked patients remains a matter for further investigation. In the interim, periodic monitoring of K+ is warranted in any patient receiving medications known to alter the state of activity of the beta-adrenoceptor. In particular, careful consideration must be given to the potential impact of various interventions (SCh administration, K+ infusion) on K+ levels in beta-adrenoceptor blocked patients.
Allergic reactions during anesthesia.
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Administration of anticholinesterase drugs in the presence of beta-adrenergic blockade.
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Opiate receptors and endorphins: their role in anesthesiology.
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Changes in blood pressure with varying rates of administration of d-tubocurarine.
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