Haemodynamic effects of glycopyrrolate pre-treatment before phenylephrine infusion during spinal anaesthesia for caesarean delivery

BackgroundPhenylephrine given during spinal anaesthesia for caesarean delivery often induces a decrease in heart rate which may decrease cardiac output. Anticholinergic drugs may be given to attenuate this effect but may also cause more labile blood pressure. This study evaluated the effects of glycopyrrolate pre-treatment on non-invasively measured cardiac output and accuracy of blood pressure control.MethodsAt induction of spinal anaesthesia for caesarean delivery, 104 patients randomly received intravenous glycopyrrolate 4 μg/kg or saline placebo. Systolic blood pressure, measured at 1-min intervals, was maintained near baseline using closed-loop feedback computer-controlled phenylephrine infusion with crystalloid cohydration. Cardiac output and stroke volume were measured using suprasternal Doppler ultrasonography at baseline and 5-min intervals for 20 min. Blood pressure control was assessed using performance error calculations.ResultsEleven patients were excluded. Patients who received glycopyrrolate (n = 45) had greater cardiac output over time (P < 0.001), greater heart rate over time (P < 0.001), similar stroke volume over time (P = 0.95), and lower median phenylephrine infusion rate (P = 0.006) compared with control (n = 48). There was no difference in the incidence of hypotension between groups. Analysis of blood pressure control showed greater positive bias, greater inaccuracy and greater wobble in the glycopyrrolate group (all P < 0.05). Neonatal outcome was similar between groups.ConclusionsGlycopyrrolate 4 μg/kg given at the start of a phenylephrine infusion increased heart rate and cardiac output but also decreased accuracy of blood pressure control, increased the incidence of hypertension and caused an increased incidence of dry mouth postoperatively compared with control.     

品管圈活动在降低血液透析相关性低血压发生率中的作用

目的探讨应用品管圈（quality control circle,QCC）方法降低血液透析相关性低血压发生率的效果。方法选择2011年10月在航空总医院血液透析中心发生透析相关性低血压患者21例为研究对象,成立品管圈活动小组、确立活动课题,进行现状调查、分析发生血液透析相关性低血压的原因、设定目标值、制订对策并实施,比较实施品管圈活动前后低血压的发生率。结果开展品管圈活动后血液透析相关性低血压发生率从15．00％下降到5．38％,活动前后比较,差异具有统计学意义（P〈0．05）。结论品管圈活动可降低血液透析相关性低血压发生率。     

血液透析中相对血容量与血压的相关性

目的 观察血液透析低血压倾向患者血液透析时相对血容量的改变,并与血压进行相关性分析,以研究相对血容量对预测低血压发生的价值.方法 挑选维持性血液透析者61例（透析龄≥1个月）,持续在线监测相对血容量,每30分钟测定血液和心率.记录140次血液透析过程中低血压的发生次数及相对血容量的数值.采用线性相关分析进行数据统计.结果 相对血容量与收缩压之间无相关性（相关系数r为0.17）.发生低血压时,患者相对血容量变化差异显著.在21例患者中,49例次相对血容量与收缩压呈线形相关.结论 在透析过程中,患者所能耐受的血容量下降程度存在明显的个体差异,但个体内变异不大,患者临床表现结合血容量监测有助于防治透析过程中低血压的发生以及确定合适的超滤量、调整干体质量.     

Changes in Vascular Tone Occur Early During Hemodialysis Treatments Independently of Volume Reduction

Hypotension commonly occurs during hemodialysis (HD). Hypotension can result from an absolute reduction in plasma volume following excessive ultrafiltration or from a reduction in vascular tone. We hypothesized that changes in vascular tone could occur during dialysis. Aortic pulse wave velocity (aPWV) was measured in 197 HD patients, mean age 63.3 ± 16.6 years, 62% male, 49% diabetic, during a single HD session. aPWV did not change (9.6 ± 2.2 vs. 9.6 ± 2.2 m/s) with HD. Systolic blood pressure (SBP) declined from 151 ± 31 to 147 ± 32 after 20 min and to 140 ± 36 mm Hg on completion of HD (P < 0.05), with an ultrafiltration volume of 2.2 ± 0.9 L over a 3.9 ± 0.4 h HD session. Aortic SBP declined from 154 ± 32 to 146 ± 29 after 20 min and 143 ± 35 at the end of HD, P < 0.001. Aortic augmentation index (Aortic Aix) decreased from 65% (52–79%) to 36.7% (23.3–52.9%) by 20 min and to 34.3 (15.1–49.1%) on completion of HD (P < 0.05), and brachial augmentation index (brachial Aix) from 5.7% (?25.2 to 27.5%) to ?1.9% (?2.2 to 30.1%) and ?6.6% (?44 to 22.7%), respectively, P < 0.05. Diastolic reflection area (DRA) increased from 36.7 (27.9–46.3) to 40.4 (32.2–51) after 20 min and 47.1 (34.2–60.5) on completion of HD, P < 0.05. We report changes in arterial tone within 20 min of starting HD, when minimal ultrafiltration has occurred, suggesting that volume changes may not be the only predisposing cause of intradialytic hypotension. The combination of a fall in SBP and a rise in DRA would suggest a reduction in coronary blood flow in keeping with reports of “myocardial stunning” during HD.     

维持性血液透析患者自体动静脉内瘘血栓影响因素观察

目的观察维持性血液透析(maintenance hemodialysis,MHD)患者血浆同型半胱氨酸(homocysteine,Hcy)、C反应蛋白(C-reactive protein,CRP)水平及透析低血压发生率等指标是否影响自体动静脉内瘘(autogenous arteriovenous fistulas,AVF)血栓的发生。方法选择以自体AVF为血管通路的MHD患者92例,观察1年是否有过1次或1次以上的内瘘血栓栓塞事件,将其分为AVF血栓组和非AVF血栓组。比较2组患者的透析中低血压发生率、Hcy、CRP、低密度脂蛋白(low density lipoprotein,LDL)、血浆白蛋白(albumin,Alb)、血红蛋白(hemoglobin,Hb)、红细胞比容(hematocrit value,Hct)、铁蛋白等1年内两次化验的平均值指标及透析时间,并进行相关危险因素分析。结果入选92例MHD患者的透析低血压发生率为19.6%(18/92),AVF血栓组和非AVF血栓组的透析低血压发生率比较,差异有统计学意义(P0.05)。92例MHD患者Hcy异常发生率为100%,但2组患者的血浆Hcy水平差异无统计学意义,2组患者的CRP和铁蛋白水平差异也无统计学意义。危险因素分析提示Hb和透析低血压是AVF血栓形成的危险因素,Hcy、CRP不是AVF血栓形成的危险因素。AVF血栓组的透析时间及Hct低于非AVF血栓组,其差异有统计学意义(P0.05),其他白细胞、SCr、血小板、LDL、Alb等生化指标的差异无统计学意义。结论透析低血压、Hb都是MHD患者AVF血栓发生的危险因素,而Hcy、CRP等与AVF血栓的发生无相关性。     

Cerebral blood flow in essential hypotension during emotional activation

Variations of blood flow velocity in the left and right middle cerebral arteries (MCA) were measured in 20 hypotensive women and 20 normotensive control subjects during emotional stimulation using functional transcranial Doppler sonography (fTDS). The emotional stimuli were composed of three series (neutral, pleasant, and unpleasant) of 20 pictures from the International Affective Picture System (IAPS). Both groups exhibited greater increases in right than left MCA blood flow during emotional stimulation. However hypotensive subjects showed smaller increases in blood flow than did normotensive controls. Furthermore hypotensives exhibited lower MCA blood flow velocity in both hemispheres at rest than did normotensives. Nevertheless the hypotensive group rated the emotional pictures as more arousing than did the control group. Results suggest a decreased blood flow, in addition to peripheral, in the central nervous system (CNS) of hypotensives, which was associated with normal emotional responses for both valence and hemispherical asymmetry, but also with a general increase of arousal levels. This dissociation might be related to an increase in anterior cerebral arteries (ACA) blood flow and/or to hypotension-mediated baroreceptors' up-regulation to the reticular system.     

系统性毛细血管渗漏综合征的临床研究进展

系统性毛细血管渗漏综合征为一组反复发作的低容量性低血压、血液浓缩、非蛋白尿性低蛋白血症 ,全身水肿、多数情况下伴有异型球蛋白血症的临床综合征。其原因由于毛细血管通透性增加 ,目前具体发病机理尚不明确。近年发现特布他林和茶碱对预防发作有效。临床医生应对该病提高警惕性。     

Manejo intraoperatorio de la presión arterial

Intraoperative mean blood pressure of <60-70 mmHg is associated with a higher prevalence of myocardial injury in non-cardiac surgery, acute kidney injury and mortality. Systolic blood pressure of <100 mmHg is also associated with an increase rate of myocardial injury in non-cardiac surgery and mortality.The injury is related to the severity and duration of intraoperative hypotension episode. Avoiding the mean arterial blood pressure to decrease below >30% of baseline, is recommended. It is reasonable to normalize mean blood pressure to baseline values as soon as possible. Baseline blood pressure defined as the usual blood pressure at home or blood pressure in the preoperative assessment. Although the evidence is not conclusive, it is reasonable to avoid the blood pressure to increase >180 mmHg or mean blood pressure >110 mmHg. Importantly, noting that current evidence shows there is a much higher risk of injury associated with a mean blood pressure lower than >30% of baseline, than associated with an increase of systolic blood pressure >180 mmHg.It is reasonable to use low dose of prophylactic vasopressors, as well as, hypnotics with less effect on systemic vascular resistance (etomidate or ketamine) on high risk patients (severe septic shock, severe hypovolemia, severe left or right ventricle systolic impairment) to avoid anesthesia induction-associated hypotension.It is reasonable to attenuate the hemodynamic response associated to laryngoscopy and intubation, with short half-live drugs, in selected patients (chronic hypertension poorly controlled and hypertension in elderly more than 70 years-old).To determine the cause of the hypertension and the presence of problems associated with hypertension might be crucial to choose the best antihypertensive drug and, therefore, leading to the most appropriate hypertension treatment.