Soon Yul Kim

Different Brain Activation Patterns to Pain and Pain-related Unpleasantness during the Menstrual Cycle

Background:The changes in the functional magnetic resonance imaging signal during anticipation, pain stimulation, and the poststimulation periods were investigated to determine whether changes in sex hormones affect brain activity. Methods:Eighteen participants were examined twice, once in the follicular phase and once in the luteal phase. Half the participants were tested first during the follicular phase, and the other half were tested first in the luteal phase. Results:The pain and unpleasantness ratings were significantly higher in the luteal phase than in the follicular. During the anticipation of pain, the prefrontal cortices were activated during the follicular phase, whereas the parahippocampal gyrus and amygdala were activated during the luteal phase. During the pain stimulation, putamen and cerebellum and precentral gyrus involving motor preparation and defense mechanism related to antinociceptive behavior were activated during the follicular phase, whereas the thalamus was activated during the luteal phase. During the poststimulation periods, the prefrontal cortices were activated during the follicular phase, whereas parahippocampal gyrus was activated during the luteal phase. The temporal pole was activated during the anticipation, pain stimulation, and poststimulation periods of the luteal phase. Conclusions:During surgical and medical procedures, requirements of anesthetic and analgesic and anxiolytic drugs may be reduced during the follicular phase and increased during the luteal phase. These results highlight the need to consider the effects of the sex hormones in women when designing clinical or neuroimaging studies or when treating patients for pain and pain-related unpleasantness.

Aging impairs vasodilatory responses in rats

Background Aging causes profound changes of stiffness and compliance in the cardiovascular system, which contributes to decreased cardiovascular reserve. Mechanisms of the underlying endothelial vasodilator dysfunction in vasodilator signaling pathways may occur at multiple sites within any of these pathways. Methods Age-related changes in the vasculature were investigated in adult young (3-6 months, Y) and old (26-29 month, O) Wistar rats (n = 6). The aortas were carefully dissected from the rat and cut into rings 1.5-2.0 mm in length to measure in vitro isometric tension. Vasorelaxant responses of aortic rings to acetylcholine (ACh), sodium nitroprusside (SNP) and P1075 were examined using Dose Response software (AD Instruments, Mountain View, CA). Results Endothelium-dependent vasodilator function was impaired. The endothelium of aging rats impaired endothelial NO dependent vasodilation, but the machinery for vasodilation was not impaired. Conclusions Age-related NO-mediated vasorelaxation in the aging endothelium was inhibited and appears to be major mechanism of vascular change and impaired vascular regulation.

Ankle-brachial blood pressure differences in the beach-chair position of the shoulder surgery.

Background During shoulder surgery, blood pressure is frequently measured at the ankle. Anesthetic complications may result when ankle blood pressure is higher than brachial blood pressure and anesthesiologists misinterpret ankle blood pressure as brachial blood pressure. Therefore, we investigated whether ankle blood pressure is significantly higher than brachial blood pressure before anesthesia induction, during induction, after tracheal intubation, before beach chair position, and in the beach chair position. Methods Thirty patients requiring general anesthesia for shoulder surgery were included in this study. Ankle and brachial blood pressure were simultaneously measured before induction, during induction, after intubation, before beach chair position, and in the beach chair position. Results Ankle blood pressure was higher than brachial blood pressure before induction, during induction, after intubation, before beach chair position, and in the beach chair position. Ankle-brachial blood pressure differences in the beach chair condition were much higher than in four other conditions. The correlation coefficient between mean ankle-brachial blood pressure differences before the beach chair position and mean ankle-brachial blood pressure differences in the beach chair position was 0.616. Brachial systolic blood pressure could be predicted by regression equations (R2 = 0.306-0.771). Conclusions These results suggest that anesthesiologists should consider these ankle-brachial blood pressure differences when monitoring anesthesia in the beach chair position.

Anesthetic complications due to extremely low ankle blood pressure caused by peripheral arterial disease

We report a case of anesthetic complications that resulted when anesthesia was monitored by measuring the ankle blood pressure. Extremely low ankle blood led to the administration of vasoactive drugs, the appearance of premature ventricular complexes (PVCs), light anesthesia, and recall of intraoperative pain. An 89-year-old man (60 kg, 168 cm) was scheduled for open reduction and internal fixation for fracture of the surgical neck of the right humerus. His past medical history included a diagnosis of hypertension 50 years ago and a 40 pack-year smoking history. An electrocardiogram (ECG) revealed premature atrial complexes and anterolateral ischemia, and basic blood chemistry revealed elevated creatinine (1.53 mg/dl; reference range: < 1.4 mg/dl). When the patient arrived in the operating room, his blood pressure was measured at the left ankle, using an automatic sphygmomanometer. His initial ankle blood pressure, before induction, was 115/98 mmHg, and heart rate was 65 beats/min. Anesthesia and surgery were performed in a supine position. Following preoxygenation, anesthesia was induced with thiopental 200 mg and remifentanil infusion 0.1 µg/kg/min. Rocuronium 50 mg was administered to facilitate orotracheal intubation with a cuffed tube. Anesthesia was maintained with sevoflurane 1.5-2.0% in a 50% oxygen and remifentanil infusion, with positive pressure ventilation in a circle system. The administration of anesthetic agents was adjusted, according to the patients blood pressure. After tracheal intubation, his ankle blood pressure was 93/24 mmHg and heart rate was 99 beats/min. Because the diastolic pressure was low, ephedrine 8 mg was administered twice. However, his ankle systolic blood pressure decreased further; blood pressure was 73/28 mmHg and heart rate was 75 beats/min. In order to increase the blood pressure, the sevoflurane concentration and remifentanil infusion rate were decreased. The patient received an intravenous bolus of phenylephrine 60 µg, plus a continuous infusion of phenylephrine at 1.5 µg/kg/min. The phenylephrine infusion was titrated, according to the blood pressure of the patient. PVCs appeared and lidocaine 60 mg was intravenously administered. The left radial artery was cannulated and blood pressure was continuously monitored. At that moment, the blood pressure measured, at the left radial artery, was 199/80 mmHg, while the left ankle blood pressure was 93/43 mmHg. The sevoflurane concentration and remifentanil infusion rate were increased and the phenylephrine infusion was stopped. The patients radial blood pressure decreased and the PVCs disappeared. Thereafter, the left ankle and brachial blood pressures were simultaneously measured during anesthesia. The left ankle blood pressure (62/40 mmHg) was lower than the left brachial blood pressure (139/53 mmHg) and the right ankle blood pressure (104/87 mmHg). The left brachial blood pressure was used to monitor anesthesia, and the target systolic blood pressure was <140 mmHg. However, because the left ankle blood pressure was extremely low (e.g. 39/15 mmHg 15 minutes after skin incision), in order to maintain blood flow to the left lower extremity, the left brachial blood pressure was intermittently kept high by decreasing the anesthetic concentrations. These anesthetic methods might result in light anesthesia and recall of intraoperative pain. The total anesthetic duration and surgery duration were 115 and 70 minutes, respectively. When the patient was fully awake, he complained of intraoperative recall and pain experienced during anesthesia. Ten days after surgery, the arterial Doppler waveform was measured, using ImexLab 3000DX (portable Doppler, Nicolet Vascular [formerly Imex Medical Systems], Golden, CO, USA). The Doppler waveform was measured bilaterally at four sites: the dorsalis pedis artery, posterior tibial artery, popliteal artery, and femoral artery. There were obstructed waveforms in the arteries on the left side, when compared to those on the right side with diminished waveform height, rounding of the waveform, and loss of diastolic flow reversal (Fig. 1). Because there were obstructed waveforms from the left dorsalis pedis artery to the left femoral artery, we suspect that the obstruction might exist between the aortic bifurcation of the left common iliac artery and the left femoral artery. Fig. 1 Doppler waveforms measured bilaterally in four sites: the dorsalis pedis artery (DPA), posterior tibial artery (PTA), popliteal artery (PA), and femoral artery (FA). There are obstructed waveforms with diminished waveform height, rounding, and loss of ... Peripheral arterial disease is chronic arterial occlusive disease of the lower extremities, which is caused by atherosclerosis [1]. The ABI (ankle-brachial index) is the ratio of the ankle to brachial systolic blood pressure. An ABI < 0.90 indicates the presence of peripheral arterial disease [2]. An ABI between 0.90 and 0.71 indicates mild obstruction, between 0.70 and 0.41 moderate obstruction, and less than 0.41 indicate severe obstruction [3]. The ABI of the present case was 0.61 [77 (ankle SBP)/126 (brachial SBP)] at rest (ten days after surgery) and was 0.28 [39 (ankle SBP)/140 (brachial SBP)] ten minutes after skin incision in the operating room. Although not completely understood, the ABI decrease from 0.61 to 0.28 during anesthesia suggests that the obstruction, due to peripheral vascular disease, might have been aggravated during anesthesia. This also suggests that blood flow, distal to the obstruction site, should be adequately maintained during anesthesia when peripheral arterial disease exists. A recent study has shown that inadequate blood pressure monitoring is associated with inadequate intraoperative blood transfusions, vasopressor infusions, and antihypertensive medication administration [4]. In the present case, inadequate blood pressure monitoring resulted in inadequate vasopressor infusion and the appearance of PVCs. PVCs may be caused by many medical conditions, including high blood pressure, stress, heart attack, and heart disease. Acute elevation in blood pressure may be associated with the generation of PVCs and the incidence of PVCs may be reduced by induced hypotension [5]. Ten days after the surgery, the left ankle blood pressure was 77/47 mmHg and the left brachial blood pressure was 126/55 mmHg. What was the reason that the left ankle blood pressure was 115/98 mmHg before induction? It may be that preoperative stress might increase the left ankle blood pressure before induction. If patients brachial blood pressure was measured before induction, anesthesia might be delayed because of high brachial blood pressure. In conclusion, this case suggests that brachial blood pressure should be measured before induction and during anesthesia in upper extremity operations, even if the intravenous line is in the unoperated upper extremity. During preoperative evaluation, anesthesiologists should be aware of the possibility of peripheral arterial disease in patients with risk factors, including old age, cigarette smoking, diabetes mellitus, and hypertension.

Cardiac arrest in the elderly with silent myocardial ischemia during general anesthesia.

Coronary artery disease (CAD) is a leading cause of mortality and morbidity in the elderly. As with myocardial ischemia, some patients with myocardial infarct may be completely asymptomatic or symptoms may be so vague that they are unrecognized by the patient. Routine electrocardiogram (ECG) sometimes cannot diagnose the signs of it [1]. When we anesthetize the elderly with silent myocardial ischemia (SMI), he can be exposed to a high risk of cardiac arrest during anesthesia. If ECG cannot rule out SMI, We have to find another test for searching SMI. We experienced cardiac arrest of the elderly with SMI during general endotracheal anesthesia. We gave routine anesthesia to the elderly patient for ENT surgery, but after anesthesia, severe cardiac arrhythmia and arrest occurred. After proper treatment, though he recovered, he might have cardiovascular injuries. If one test checked out the elderly with SMI, the accident would not have occurred during anesthesia. We want to report the case and study with a literature review. A 65 years old man whose height and weight were 164 cm and 50 kg, respectively, visited our hospital to undergo surgery for a laryngeal nodule under general endotracheal anesthesia. He did not present diabetes mellitus and hypertension in past history. The patient had a nodule-like opaque shadow of the right lung in chest PA, rightward axis and bradycardia (54 beats/ min) in the electrocardiogram. The other laboratory findings were non-specific and he did not have any another symptoms. His blood pressure was 140/80 mmHg, pulse rate was 90 beats/ min, oxygen saturation of pulse oximeter was 97% on arrival of operation room. We induced the elderly gentleman with propofol 100 mg, atracurium 30 mg after full mask ventilation with 100% oxygen. He was soon anesthetized, and intubated by direct laryngoscope with 6.o sized right angle preformed tube. When intubated, his blood pressure was 190/100 mmHg, he was ventilated with a tidal volume of 500 ml by an anesthetic machine. Continuous anesthetic maintenance was oxygen 2 L/ min, N2O 2 L/min, sevoflurane 2 -3 vol%. After 10 minutes, his cardiac rhythm was irregular in the electrocardiogram, blood pressure was not able to check in noninvasive blood pressure. Cardiopulmonary resuscitation was performed, He recovered and soon, vital signs were stable. The surgery was discontinued and he was transferred to a coronary angiographic room. We could see two coronary arteries stenosis, which were 80% stenosis in the circumflex branch of the left coronary artery and 50% stenosis in the middle branch of the right coronary artery in the coronary angiogram (Fig. 1). Aging is a universal and progressive physiologic process characterized by the declining end-organ reserve, decreased functional capacity, increasing imbalance of homeostatic mechanisms, and an increasing incidence of pathologic processes [2]. Especially in the cardiovascular system, the aging process is associated with primary and secondary changes in the heart, primary changes in the blood vessels, and alterations in autonomic control. As the heart ages, changes in morphology occur. Myocyte count deceases, left ventricular wall thickening occurs, and the conduction fiber density and sinus node cell number decrease [3]. Age related diseases in the cardiovascular system are hypertension, diabetes mellitus, ischemic heart diseases, and they exhibit a higher incidence in elderly individuals.

The vasorelaxatory effect of the milrinone on the preconstricted rat aorta

BACKGROUND Milrinone, phosphodiesterase III inhibitor, has been used effectively in patients with right heart failure, especially resulted from pulmonary hypertension. However, milrinone is often used with alpha- and beta-adrenergic receptor agonist to prevent severe systemic vasodilation and unfavorable hypotension. Furthermore, structural and functional vasacular changes are associated with aging and are greatest in the aorta. We evaluated the vasodilatory effects of milrinone and sodium nitroprusside (SNP) on young and old rat aortic rings preconstricted with various catecholamines. METHODS Aortic rings of young and old rat were placed in 25 ml organ chamber and preconstricted with epinephrine (EPI, 10(-6) M), norepinephrine (NE, 10(-7) M) , phenylephrine 10(-7) M) , and U46619 (10(-8) M). Cummulative dose-responses to milrinone (10(-9)-10(-5) M) and SNP (10(-9)-10(-5) M) were obtained to characterize vasodilatory effects. RESULTS Relaxation response to milrinone was markedly enhanced in both young and old aortic rings preconstricted with U46619 compared with other vasoconstrictors. The maximal response of the young rat aortic rings preconstricted with NE is significantly reduced, compared with that of EPI. The maximal vasorelaxant response of SNP in young and old aortic rings are nearly identical. CONCLUSIONS We conclude that combined use of milrinone and epinephrine may be more useful in prevention and treatment of systemic hypotension.