Day and night blood pressure variability among older persons in South­Western Nigeria

Background: Hypertension is the largest contributor to the global burden of disease. Emerging risk factors for cardiovascular disease include blood pressure variability (BPV), but evidence on BPV is lacking among older Nigerians. We reported BPV in a cohort of older persons at the University College Hospital (UCH), Ibadan. Methods: We conducted a retrospective cohort study of respondents aged >50 years within the Ibadan Ambulatory Blood Pressure Registry at the UCH, Ibadan, Nigeria. Socio-demographic characteristics, lifestyle habits and anthropometric measurements were obtained. Results: Among 639 respondents, 332 (52.0%) were female. The blood pressure (BP) variables were strongly associated with age. Compared with younger age groups, mean diastolic BP (DBP) was less at an older age, whereas mean pulse pressure was greater. During the wake-up and sleep periods, mean DBP and mean arterial BP were less with each increasing age category, whereas mean pulse pressure was larger with each increasing age category. BP dipping, systolic, diastolic and mean arterial BP decreased with age. Overall, timed BPV increased significantly with increasing age. The prevalence of white­coat hypertension was greater among older participants than younger participants. Most respondents in the 50­59 years' age group were non-dippers (55.8%), whereas 33.7% of older respondents were reverse-dippers. Conclusion: Older persons experienced a greater abnormal circadian blood variation and greater BPV than younger people. In Nigeria, follow­up data are needed to determine the prognostic significance of these data in this population

Low Dose Sufentanil with Esmolol in Reducing the Increase of Heart Rate and Blood Pressure after Endotracheal Intubation / 대한마취과학회지

BACKGROUND: Laryngoscopy and tracheal intubation usually induce tachycardia and hypertension. Various drugs including esmolol and fentanyl have been employed to reduce the cardiovascular response accompanying laryngoscopy and intubation. The purpose of this study is to assess the efficacy of low dose sufentanil with esmolol in reducing hypertension and tachycardia induced by endotracheal intubation. METHODS: Forty surgical patients from Kosin medical hospital were randomly assigned to receive either normal saline (n = 20, control group) or sufentanil (0.3 microgram/kg) with esmolol (1 mg/kg) (n = 20, S & E group) before anesthetic induction. Anesthesia was induced intravenously with pentothal sodium 4 mg/kg followed by endotracheal intubation after succinylcholine 1 mg/kg. Changes in systolic blood pressure, mean arterial blood pressure, diastolic blood pressure, heart rate, and SpO2 (arterial oxygen saturation by pulse oximeter) were measured at 30 seconds, 1 minute, 2 minutes, 3 minutes, 4 minutes and 5 minutes following intubation. The values of each group were compared with preinduction baseline values, and the S&E group was compared with the control group. Data were analyzed for statistical significance using repeated measures of ANOVA and chi-square test. RESULTS: In the S&E group, the systolic and mean arterial pressures at 30 seconds and 1 minute, and diastolic blood pressure at 30 seconds after intubation were significantly lower than the values of the control group (P < 0.01). The heart rates at 30 seconds, 1 minute were significantly lower compared to the control group (P < 0.01 and P < 0.05, respectively). CONCLUSIONS: The results suggest that pretreatment of low dose sufentanil with esmolol is effective to reduce the elevation of blood pressure and heart rate due to laryngoscopy and intubation.

Role of Perfusion Pressure in Major Organ Blood Flow during Cardiopulmonary Bypass in Canines / 대한마취과학회지

BACKGROUND: There has been no report about the effects of blood pressure (BP) on the change of blood flow (BF) to major organs when pump flow is maintained during cardiopulmonary bypass (CPB). We evaluated the changes of the BF and oxygen consumption of major organs when BP was controlled by vasopressors or vasodilators during CPB. METHODS: Carotid, femoral, hepatic and renal arteries and veins were exposed and arteries were cannulated for pressure monitoring, except the hepatic artery and arteries on the opposite side were exposed for the measurement of BF in 7 dogs. Temperature was lowered to 30oC after initiation of CPB and phenylephrine or sodium nitroprusside was infused to increase or decrease BP about 30% under the same pump flow. BP and BF were measured before CPB, before the infusion of drugs and when BP was changed by vasoactive drugs. Blood gas analyses were performed from the artery and each vein while the BF was measured. RESULTS: The change of BP didn't affect carotid and renal BF. However, hepatic BF decreased about 50% when BP was reduced and femoral BF changed in the opposite way of BP change. Oxygen consumption of each organ wasn't influenced by BP. CONCLSIONS: When pump flow was constantly maintained, changes in BP redistributed BF to major organs but didn't affect oxygen consumption. The brain and kidney have the ability of autoregulation of BF unlike the liver or legs. Hepatic BF was dependent on perfusion pressure and a decrease in BP by vasodilators during CPB may be not good for the liver.

Correlation between the Change of Mean Arterial Pressure and the Change of Percutaneous Oxygen Saturation in Patients with Tetralogy of Fallot / 대한마취과학회지

BACKGROUND: Hypoxia often occurs during anesthesia of patients with tetralogy of Fallot (TOF). The factors that determine pulmonary circulation and oxygenation in patient with TOF are the degree of obstruction of right ventricular outflow tract (RVOT), right ventricular filling pressure, systemic vascular resistance, loss of negative pleural cavity pressure by thoracotomy, change of pulmonary vascular resistance due to positive pressure ventilation and degree of arteriopulmonary collateral connection. Hence pulse oximetry is a noninvasive technique for measuring arterial O2 saturation continuously, this study examined the correlation between the change of percutaneous arterial oxygen saturation (delta SpO2) and the change of mean arterial pressure (delta MAP) using pulse oximetry in these patients. METHODS: Twenty pediatric patients undergoing modified Blalock-Taussig shunt or total corrective operation were prospectively investigated. Immediately after induction, baseline values of MAP and SpO2 were determined and if there were some changes in SpO2 from baseline during operation, MAP on that value of SpO2 were collected. If SpO2 reduced, patients were treated with infusion of fresh frozen plasma or pentastach (2-10 ml/kg), injection of phenylephrine (10 microgram/kg) or esmolol (0.5 mg/kg). RESULTS: Intravascular volume loading only was executed in 4 patients, intravascular volume loading and phenylephrine administration was executed in 11 patients, and intravascular volume loading, phenylephrine and beta-blocker administration was executed in 5 patients. There were no significant correlation between delta MAP and delta SpO2 from linear correlation and regression analysis (r=0.23, p<0.05). CONCLUSIONS: Because delta SpO2 were not closely related with delta MAP and above mentioned factors could act closely among each others, meticulous anesthetic management is necessary during palliative or total corrective operation in patients with TOF.

Comparative Study of Light Wand and Direct Laryngoscope: Correlation of Time to Intubation and Thyromental Distance, and Change of Blood Pressure and Heart Rate after Intubation / 대한마취과학회지

BACKGROUND: Direct laryngoscope may be less useful under conditions of limited visualization. Light wand is a lighted stylet to transilluminate neck tissues allowing intubation without visualization. Thus, difficult intubation due to anatomy can be overcome. For comparison of light wand and direct laryngoscope, we checked time to intubation (TTI), success rate, relation of TTI and thyromental distance (TMD), and change of blood pressure and heart rate after intubation. METHODS: We selected and randomly allocated sixty adults to direct layngoscope group (D) and light wand group (L). Without premedication, propofol and vecuronium were injected for intubation. Time to intubation was measured from the time of grasping direct laryngoscope or light wand until the time of inserting endotracheal tube into trachea. We checked the change of blood pressure and heart rate after intubation, and studied the correlation of TTI and TMD. RESULTS: TTI was 16.5 sec (6.53~115.3 sec) for group D and 11.8 sec (4.31~36.0 sec) for group L. There was no significant difference between the groups. The rise of blood pressure and heart rate was less with light wand. There was a correlation of [TTI]=1248- 388[TMD]-30[TMD]2 in group L patients whose TMD is less than 7 cm. CONCLUSION: Compared with direct laryngoscope, light wand is as easy to use and can be more effective especially for patients whose anatomy may make intubation difficult or whose cardiovascular system is unstable.

Comparative Study of Light Wand and Direct Laryngoscope: Correlation of Time to Intubation and Thyromental Distance, and Change of Blood Pressure and Heart Rate after Intubation / 대한마취과학회지

BACKGROUND: Direct laryngoscope may be less useful under conditions of limited visualization. Light wand is a lighted stylet to transilluminate neck tissues allowing intubation without visualization. Thus, difficult intubation due to anatomy can be overcome. For comparison of light wand and direct laryngoscope, we checked time to intubation (TTI), success rate, relation of TTI and thyromental distance (TMD), and change of blood pressure and heart rate after intubation. METHODS: We selected and randomly allocated sixty adults to direct layngoscope group (D) and light wand group (L). Without premedication, propofol and vecuronium were injected for intubation. Time to intubation was measured from the time of grasping direct laryngoscope or light wand until the time of inserting endotracheal tube into trachea. We checked the change of blood pressure and heart rate after intubation, and studied the correlation of TTI and TMD. RESULTS: TTI was 16.5 sec (6.53~115.3 sec) for group D and 11.8 sec (4.31~36.0 sec) for group L. There was no significant difference between the groups. The rise of blood pressure and heart rate was less with light wand. There was a correlation of [TTI]=1248- 388[TMD]-30[TMD]2 in group L patients whose TMD is less than 7 cm. CONCLUSION: Compared with direct laryngoscope, light wand is as easy to use and can be more effective especially for patients whose anatomy may make intubation difficult or whose cardiovascular system is unstable.

Age-related Difference of the Vagal Reflex and Baroreceptor Reflex under General Anesthesia with Enflurane / 대한마취과학회지

BACKGROUND: Baroreceptor reflex responds to the decrease in blood pressure caused by drug, dehydration, or severe bleeding. Vagal reflex caused by direct pressure on vagus nerve, the traction, or lung inflation develops bradycardia and severe arrhythmia. Lung inflation elicits a vasodepressor reflex, resulting in stimulation of the vagus nerve which causes a decrease in sympathetic outflow. METHODS: 75 patients who had elective surgery were divided into 3 groups according to the age, such as group I: or = 65 years of age. Lung inflation test has been performed at 20 cmH2O for 20 seconds. Baroreceptor was stimulated by lowering blood pressure with intravenous infusions of nitroglycerin. Baroreceptor sensitivity was assessed by measuring the decrease in blood pressure. Vagal reflex sensitivity was calculated by the subtraction of G2 (baroreceptor reflex sensitivity after introglycerin infusion) from G1 (heart rate response to lung inflation). RESULTS: Baroreceptor reflex induced by hypotension and vagal reflex originated from lung influe-nced the heart rate inversely when lung inflated. Baroreceptor reflex sensitivity was highest in younger patients and lowest in older patients when nitroglycerin infused. Vagal reflex sensitivity was highest in older patients and lowest in younger patients. CONCLUSIONS: Baroreceptor reflex was most sensitive in younger patients, but vagal reflex was moresensitive in older patients.

Effects of Diltiazem on Mean Arterial Pressure and Heart Rate during Tracheal Extubation in Hypertensive Patients / 대한마취과학회지

BACKGROUND: Tracheal extubation provokes hypertension and tachycardia, as does tracheal intubation. Especially hypertensive patients are more likely to exhibit substantial fluctuations in hemodynamics and myocardial ischemia than normotensive patients during these stressful periods. The aim of present study was to evaluate the effects of intravenous diltiazem in attenuating mean arterial pressure(MAP) and heart rate(HR) responses to tracheal extubation in hypertensive patients. METHODS: Thirty-seven hypertensive patients who were to undergo elective surgery were randomly assigned to one of three groups : saline (control), lidocaine 1 mg/kg, and diltiazem 0.2 mg/kg. These drugs were given 2 minutes prior to tracheal extubation. Anesthesia was induced by the injection of fentanyl 1.5 microgram/kg, thiopental 5 mg/kg, and vecuronium 0.1 mg/kg and maintained with 50% N2O in O2 and 1~2 vol.% enflurane. Changes in HR and MAP were measured during and after tracheal extubation. RESULTS: In the diltiazem group, the MAP decreased significantly at drug administration, extubation, and post-extubation 1 min. However there were no significant differences in HR among 3 groups. CONCLUSIONS: These data suggest that intravenous injection of diltiazem 0.2 mg/kg given 2 minutes before tracheal extubation was effective in attenuating MAP changes associated with tracheal extubation. But HR changes were not different significantly among 3 groups. Further studies are required for the effective prophylaxis against tachycardia associated with tracheal extubation.

A Comparison with Infusion of Single Intravenous Anesthetic with Propofol and Fentanyl in Operation of Short Duration / 대한마취과학회지

BACKGROUND: Propofol, a new intravenous anesthetic agent, is now used for brief operation and day surgery for its rapid recovery and controllability. Propofol, rapid acting sedatives hypnotics, is known to no analgesic effect. This study was taken to evaluate the analgesic effect of propofol, compared to those of fentanyl. METHODS: Forty patients (ASA physical status 1, 2) scheduled for surgery of short duration (within 1 hour) were randomly allocated into two groups. Induction of anesthesia was performed by injection of thiopental (5 mg/kg) and succinylcholine (1 mg/kg) and ventilated with O2-N2O (50%) after endotracheal intubation. Maintenance of anesthesia was performed by vecuronium (1 mg/kg) and continuous infusion of propofol (group I) or fentanyl (group II). RESULTS: There was no significant differences in systolic and diastolic blood pressure in both groups. In heart rate, there was significant difference at preincision and postincision between two groups. Time to extubation (4.5 +/- 4.6 vs 6.3 +/- 4.6 min), time to eye open (7.5 +/- 7.1 vs 6.6 +/- 5.4 min), time to complain pain after stop dropping at recovery room (30.5 +/- 8.0 vs 35.5 +/- 17.9 min), the average flow rate of drugs (6.0 +/- 2.2 mg/kg/hr vs 6.7 +/- 2.4 microgram/kg/hr) has no significant difference between two groups. CONCLUSIONS: A single continuous infusion of propofol is applied as one of general anesthesia methods with O2-N2O, muscle relaxants. Propofol has a appropriate and similar analgesic effect compared with fentanyl in operation of little hemodynamic changes and short operation, and rapid recovery compared with fentanyl.

The Effect of Magnesium Pretreatment on Serum Potassium Concentration and Hemodynamic State in Rabbits during Continuous Regular Insulin(RI) Infusion / 대한마취과학회지

Background: Insulin is known to act as second effector that provides potassium transfer from extracellular fluid to intracellular fluid, thus causing hypokalemia and arrythmia. We evaluated the effect of magnesium sulfate treatment on hemodynamics and serum potassium concentration, induced by continuous infusion of regular insulin solution in rabbits. Method: Twenty-four rabbits were divided into four groups for the experiment. Group I was given intravenouse injection of 5 ml of normal saline and continuous dripping of 7.5 U of RI. Group II was pretreated with 30 mg/kg of magnesium sulfate, followed by continuous dripping of 7.5 U of RI. Group III was given 5 ml of normal saline and 15 U of RI. And Group IV was administered 15 U of RI after 30 mg/kg of magnesium sulfate pretreatment. Venouse blood sampling was done before pretreatment, and after 5, 30, 60 and 120 minutes respectively. Heart rate and arterial blood pressure were taken at the same intervals. Result: 1) There was no significant change in serum potassium concentration in groups injected with 7.5 units of RI respectively (groups I and II), regardless of magnesium pretreatment. But in groups injected with 15 units of RI, the group that was not pretreated with magnesium (Groups III) showed a decrease in serum potassium concentration from 3.39+/-0.57 Eq/L to 2.29+/-0.71 mEq/L, while the concentration in the pretreated group (Group IV) decreased more significantly from 3.35+/-0.50 mEq/L to 1.81+/-0.41 mEq/L. 2) Pulse rate did not change significantly in groups that received continuous infusion of 7.5 units of RI (groups I and II) regardless of magnesium pretreatment, but increased significantly in groups injected with 15 units of RI (groups III and IV), pretreated or not. The pretreated group (group IV) had a more significant rise in pulse rate compared with the group that was not pretreated (group III). 3) In all of the groups, those pretreated with magnesium (groups II and IV) and those not pretreated (groups I and III), there was no significant change in systolic and diastolic blood pressures. Nor was arrhythmia detected. Conclusion: The above results indicate that while magnesium sulfate pretreatment at 30 mg/kg with insulin infusion affects serum potassium concentration, has an antiarrhythmic effect, and may induce tachycardia, it does not have any significant effect on blood pressure.

Use of Direct Laryngoscope Improves a Hypopharyngeal Position of Laryngeal Mask Airway / 대한마취과학회지

BACKGROUND: Laryngeal mask airway (LMA) partly can be replaced for a role of endotracheal tube intraoperatively. Even with selecting one from various insertion techniques of LMA, one cannot achieve its perfect hypopharyngeal position. Furthermore, which is chosen by most anesthesiologists in this country, use of muscle relaxant for LMA insertion appears to have a harmful effect on its position. We tried to confirm whether we can improve the hypopharyngeal position of LMA with additional elevation of epiglottis using direct laryngoscope during LMA insertion. METHODS: Forty healthy patients scheduled for surgical procedure under general anesthesia were randomly divided to two groups; Laryngoscope group (n=20) and Jaw thrust group (n=20). No premedicant was administered. Anesthesia was induced with thiopental, vecuronium plus 2~3 vol% enflurane in oxygen. Full muscular relaxation was judged by no adductor response of thumb to train-of-four stimuation. In Jaw thrust group, using Brain's standard technique with additional jaw thrust, LMA was inserted, while in Laryngoscope group, LMA was introduced into oral cavity and advanced farther with additional elevation of epiglottis with direct laryngoscope. Bronchoscopic grading of hypopharyngeal position of LMA was performed. Blood pressure and heart rate were recorded at arrival (control), preintubation and until postintubation 5 minutes at 1 minute interval. Each measured values were compared between groups. RESULTS: Bronchoscopic grade of Laryngoscope group was significantly better than that of Jaw thrust group (p<0.001). Mean arterial pressure and heart rate changes were not different between groups. Conclusion: In the case of LMA insertion using muscle relaxant, we can markedly improve the hypopharyngeal placement of LMA with help of direct laryngoscope.

Thoracoscopic Sympathectomy for Hyperhidrosis Lowers Arterial Pressure Measured in Ipsilateral Arm / 대한마취과학회지

BACKGROUND: Thoracoscopic sympathectomy seems to be a safe therapeutic procedure without a severe complication. Hypotension has been often reported as one of postoperative complications, but intraoperative changes in blood pressure (BP) were not studied. However, authors' past experience of thoracic sympathectomy told that intraoperative BP reduction could be observed only when measured in ipsilateral arm. During general anesthesia, BP reduction might be a crucial, which could be associated with complication. Authors conducted this study to establish whether BP reduction is confined to ipsilateral arm, or is systemic phenomenon in thoracoscopic sympathectomy. METHODS: Twenty healthy, male and female patients scheduled for one stage thoracoscopic thoracic sympathectomy were prepared for this study. Without premedication, invasive BP monitoring was taken place in bilateral radial arteries. General anesthesia was induced with low dose of fentanyl, propofol and vecuronium. Endotracheal intubation was done with double lumen tube and anesthesia was maintained with variable concentrations of isoflurane in 100% oxygen. Sympathetomies were done for T2~3 during one lung ventilation. BP and palmar temperature were recorded at arrival, after one lung ventilation, after sympathectomy, 5 min, 10 min, after two lung ventilation. BPs and temperatures were analyzed by time and groups. RESULTS: Concurrent with initiation of sympathectomy, BP was reduced only in ipsilateral radial artery. Mean BP decrement was almost 11% (right side: 80 +/- 11 mmHg -> 71 +/- 15 mmHg; left side: 80 +/- 14 mmHg -> 71 +/- 9 mmHg; both of p<0.05). It was accompanied with ipsilateral palmar temperature elevation (right side: 1.28 degrees C; left side: 1.19 degrees C; both of p<0.05). CONCLUSION: Conclusively, BP reduction in thoracic sympathectomy is a change confined to ipsilateral arm, which seems because of peripheral vasodilation.

Arterial Blood Pressure and Heart Rate Response to Lightwand or Direct Laryngoscopy for Endotracheal Intubation / 대한마취과학회지

BACKGROUND: Tracheal intubation commonly results in sympathetic stimulation manifested by increased heart rate and arterial blood pressure. This study was carried out to determine whether lightwand would result in less hemodynamic changes than direct laryngoscopy. METHODS: With informed consent, fourty healthy female patients scheduled of elective surgical procedures were randomly allocated into two groups; lightwand (LW) or direct laryngoscopy (DL) group. Mean arterial pressure (MAP) and heart rate (HR) were recorded upon arrival. Under a standardized anesthetic technique, the patients were intubated either with no. 3 curved blade direct laryngoscopy (DL group) or with lightwand (LW group). The MAP and HR were recorded before intubation and every 1 minutes following intubaion. Time to intubation (TTI) was also recorded. All patients were intubated by a same fourth grade resident. RESULTS: Fourty patients were studied. Every intubation was successed in first attempt. The TTI was significantly shorter in LW group. Even while there was no significant difference in HR changes, there was significant difference in the increase of MAP following intubation. The increase of MAP was significantly greater with DL than with LW. CONCLUSIONS: This study suggests that lightwand intubation requires shorter TTI and may give rise to less blood pressure change than direct laryngoscopy. So we found no difference in disadvantage and may offers advantage in terms of hemodynamic stability.

Comparison of Femoral to Radial Artery Pressure during Coronary Artery bypass Graft and Valvular Surgery / 대한마취과학회지

BACKGROUND: It has been known that pressure gradient(PG) between systolic radial arterial pressure(RAP) and systolic aortic pressure(AP) is often altered after cardiopulmonary bypass(CPB). In this study, we compared radial to femoral arterial pressure(FAP) difference between valve replacement(VR) group(n=189) and coronary artery bypass graft (CABG) group(n=90). METHODS: With IRB approval, anesthesia management followed the standard method for cardiac surgery. Heart rate, RAP, FAP, cardiac index(CI), forearm skin temperature, hematocirt and systemic vascular resistance index(SVRI) were recorded at before-CPB, after-CPB and after sternal closure. RESULTS: In CABG group, there was no change of PG between RAP and FAP before and after CPB. In VR group, systolic RAP was similar with FAP before CPB but the radial-femoral arterial pressure gradient was reversed with statistical significance after bypass. Compare with CAGB group, change of pressure gradient after CPB cousiderded statistical significant in valve replacement group. CI was increased and SVRI was decreased with statistical significance. CONCLUSION: In our study, patients in VR group who demonstrated high CI and low SVRI showed reversal of PG upon cessation of CPB. Reversal of PG at post-CPB probably partially depends on the degree of systemic vasodilation upon discontinuation of CPB.