Is preoperative fasting necessary?

The effects of fasting and of histamine (H2) antagonists on gastric volume and acidity were studied in 56 baboons undergoing various surgical procedures under general anesthesia and randomly allocated into 4 groups; group A--fasted for 14 hours; group B--given 100-120 ml of water 3 hours before surgery; groups C and D--also given 100-120 ml of water 3 hours before surgery; in addition, the former received cimetidine 10 mg/kg IM and the latter ranitidine 1.5 mg/kg IM 30-40 minutes before anesthesia. There were no significant differences between groups A and B with respect to the gastric volume and pH. Both ranitidine and cimetidine significantly (P < 0.02) reduced gastric volume and increased gastric pH. Thus, prolonged withholding of oral fluids does not reduce the gastric volume or increase gastric pH. H2-antagonists are effective in reducing both gastric residual volume and pH.     

经皮电穴位电刺激足三里穴对胃癌患者术后血清IgG、IgM水平的影响

目的:观察经皮穴位电刺激对胃癌根治术患者术后血清免疫球蛋白M(Ig M)、免疫球蛋白G(Ig G)水平的影响。方法:选择全麻择期行胃癌根治术的患者102例(男88例,女14例),年龄40~75岁,将其随机分为经皮穴位电刺激组、假电刺激组和对照组。经皮电刺激双侧"足三里"(ST 36)、"三阴交"(SP 6)穴,于手术当日、术后第1日和术后第2日进行经皮电刺激治疗。于术前30分钟、术后24 h、术后72 h采集静脉血标本,测定免疫球蛋白G(Immunoglobulin G,Ig G)、免疫球蛋白M(Immunoglobulin M,Ig M)的水平。术后监测和记录肛门的排气时间。结果:在术后第1天,对照组外周血Ig G水平显著低于术前30分钟(P0.05),TEAS组外周血Ig M水平显著高于术前30分钟(P0.05),TEAS组外周血Ig G和Ig M水平显著高于对照组(P0.05)。在术后第3天,对照组外周血Ig G、Ig M水平显著低于术前30分钟(P0.05),TEAS组外周血Ig G、Ig M水平均显著低于术后1天(P0.05)。三组患者术后肛门排气时间比较无统计学差异(P0.05)。结论:经皮穴位电刺激可以升高胃癌根治术患者术后1天降低的外周血Ig G和Ig M水平,减轻其术后免疫抑制。     

BIS监测下两种快通道麻醉方式应用于鼻内镜手术的比较

目的:观察BIS指导两种快通道麻醉在鼻内镜手术中的应用及麻醉效果。方法:选择60例ASAⅠ-Ⅱ级择期行功能性鼻内镜手术(FESS)患者,随机分为七氟醚诱导维持麻醉组(VIMA组)与异丙酚全凭静脉麻醉组(TIVA组)。VIMA组:8%七氟醚,氧流量8L/min,潮气量法吸入诱导,七氟醚维持麻醉;TIVA组:异丙酚2 mg/kg诱导,异丙酚维持麻醉。两组诱导时都静脉注射瑞芬太尼1μg/kg,罗库溴铵0.6 mg/kg,监测TOF值为0、BIS60并维持5 s后行气管插管。术中静脉泵注瑞芬太尼0.2μg·kg~(-1)·min~(-1),分别调整七氟醚和异丙酚维持剂量使BIS值在气管插管后至手术结束前15 min左右保持在40~60之间,手术最后15 min保持于60~70之间。两组术后进行Steward评分,并比较两组各时点SBP、DBP、HR,拔管时间,快通道麻醉成功率和苏醒期不良反应发生率。结果:VIMA组拔管时间(11.60±2.55 min)比TIVA组的(7.13±3.26 min)明显延长(P0.05);TIVA组快通道成功率显著高于VIMA组(P0.05)。两组苏醒期不良反应的发生情况比较差异无统计学意义(P0.05)。结论:异丙酚全凭静脉麻醉用于鼻内镜手术拔管时间比七氟醚诱导维持麻醉短,快通道麻醉效果更好。     

Hemodynamic effects of perioperative stressor events during rhinoplasty

The hemodynamic effects of perioperative stressors, including preoperative patient anxiety, intraoperative local anesthetic/adrenaline infiltrations, and some painful interventions, have not been fully elucidated in plastic surgery procedures. The present study was designed to determine the hemodynamic effects of perioperative stressor events in American Society of Anesthesiologists class I patients undergoing rhinoplasty procedures under general anesthesia. The study included 50 healthy patients, 18 to 51 years of age (mean age, 27 +/- 7 years), who underwent a rhinoplasty procedure in the authors' department. All patients were connected to a digital ambulatory Holter recorder for 24 hours starting on the day before the operation and continuing throughout the procedure. All of the patients received 10 ml of 2% lidocaine with 1:80,000 adrenaline 15 minutes after intubation. Observations consisted of heart rate, noninvasive blood pressure, and power spectral heart rate variability analyses, the latter of which is indicative of the sympathovagal balance of the patients. The majority of patients developed a persistent, moderate sinus tachycardia before the induction of anesthesia. After the infiltration of lidocaine/adrenaline, a mild to moderate and short-lasting tachycardia was detected. A similar increase in pulse rate was also noticed during lateral osteotomies. No significant blood pressure changes attributable to perioperative stressors (with the exclusion of general anesthesia induction, intubation, and extubation) were observed. Sympathetic activity was found to be responsible from marked tachycardia before the induction, which was attributable to preoperative anxiety. The authors' study has demonstrated that there are three hemodynamically unstable periods causing tachycardia for rhinoplasty patients that directly concern the plastic surgeon: immediate preoperative anxiety, local anesthetic/adrenaline injection, and lateral osteotomies. The authors conclude that these patients would benefit from routine use of premedications and that a lidocaine/adrenaline combination is a safe adjunct to general anesthesia in young rhinoplasty patients. In addition, a deeper anesthesia during local infiltration and osteotomies would be appropriate.     

Intraoperative isolation and processing of BM-derived stem cells

To improve tissue regeneration of ischemic myocardium, autologous bone marrow-derived stem cells have been injected intramyocardially in five patients undergoing coronary artery bypass grafting and transmyocardial laser revascularization. An innovative method for the intraoperative isolation of CD133(+)-stem cells in less than 3 hours has been established. After induction of general anesthesia, approx. 60-240 ml of bone marrow were harvested from the posterior iliac crest and processed in the operating room under GMP conditions using the automated cell selection device Clini-MACS. Following standard CABG surgery, LASER channels were shot in predefined areas within the hibernating myocardium. Subsequently, autologous CD133(+)-stem cells (1.9-9.7 x 10(6) cells; purity up to 97%) were injected in a predefined pattern around the laser channels. Through the intraoperative isolation of CD133(+)-cells, this effective treatment of ischemic myocardium can be applied to patients scheduled both for elective and for emergency revascularisation procedures.     

术前口服碳水化合物对胃癌术后患者的影响

目的:研究胃癌患者术前口服碳水化合物的安全性及对术后胰岛素抵抗影响。方法:选取胃下部癌病理诊断明确的患者32例,取得知情同意后按照随机双盲的试验,参与者麻醉前2-3小时口服碳水化合物或安慰剂,术前4小时及术后即刻抽取静脉血测定血糖、胰岛素及C-反应蛋白浓度,通过HOMA发计算出术前术后胰岛素抵抗指数、胰岛素敏感指数、胰岛素分泌指数,并将两组进行比较。结果:与口服安慰剂组相比较,术前口服碳水化合物组的血糖、胰岛素、C-反应蛋白及胰岛素抵抗指数更低,且两组患者术后胰岛素敏感性均下降,但口服碳水化合物组的胰岛素敏感性较安慰剂组高。结论:术前2-3小时口服碳水化合物是安全有效的,且能明显术后即刻胰岛素抵抗状态,应作为术前常规处理。     

全麻复合硬膜外麻醉对胃癌根治术围术期纤溶功能的影响

目的:探讨全身麻醉复合连续硬膜外麻醉对胃癌根治患者围术期纤溶功能的影响。方法:选择2013年4月到2015年6月在我院进行胃癌根治手术的患者80例,根据随机数字表法分为治疗组40例与对照组40例,对照组给予全身麻醉,治疗组给予全身麻醉复合连续硬膜外麻醉,对两组患者血流动力学指标,纤溶功能以及下肢深静脉血栓发生情况进行观察与比较。结果:所有患者都完成手术,诱导后患者的MAP与HR值与诱导前比较差异都有统计学意义(P0.05),不过组间对比无显著性差异(P0.05),术毕MAP与HR值在组内与组间比较均无显著性差异(P0.05)。治疗组诱导后5 min与术毕的血清D-二聚体和纤维蛋白原值都明显低于对照组,且与诱导前对比差异也有统计学意义(P0.05)。治疗组术后下肢深静脉血栓发生率明显低于对照组(P0.05)。结论:全身麻醉复合连续硬膜外麻醉能改善胃癌根治患者围术期纤溶功能,从而减轻患者高凝状态,安全性好,有效预防下肢深静脉血栓的形成。     

Inhalation anesthesia in adult cattle

An inhalation technique was used for anesthesia during ileal cannulation in five adult cows. Following sedation with intravenous acepromazine, anesthesia was induced intravenously with thiopental sodium in 5% glyceryl guaiacolate solution. Endotracheal intubation was performed and anesthesia maintained with halothane in oxygen via a circle system with a precision vaporizer. In all cases, induction was smooth and no difficulties were experienced during the maintenance of anesthesia. Total anesthesia time was 1.5 to 2.5 hours. Following completion of the surgical procedure, which was performed with the animal in left lateral recumbency, each cow was rolled to a sternal position and supported, if necessary. The endotracheal tube was left in place, with oxygen administration continued, until the animal was able to swallow. Recoveries were rapid and all animals were ambulatory within 30 minutes after completion of the surgery. The only post-operative complication due to anesthesia was transient mouth soreness in two cases, attributed to the use of a mouth speculum during intubation.     

Methods of patient warming during abdominal surgery

Background

Keeping abdominal surgery patients warm is common and warming methods are needed in power outages during natural disasters. We aimed to evaluate the efficacy of low-cost, low-power warming methods for maintaining normothermia in abdominal surgery patients.

Methods

Patients (n = 160) scheduled for elective abdominal surgery were included in this prospective clinical study. Five warming methods were applied: heated blood transfusion/fluid infusion vs. unheated; wrapping patients vs. not wrapping; applying moist dressings, heated or not; surgical field rinse heated or not; and applying heating blankets or not. Patients’ nasopharyngeal and rectal temperatures were recorded to evaluate warming efficacy. Significant differences were found in mean temperatures of warmed patients compared to those not warmed.

Results

When we compared temperatures of abdominal surgery patient groups receiving three specific warming methods with temperatures of control groups not receiving these methods, significant differences were revealed in temperatures maintained during the surgeries between the warmed groups and controls.

Discussion

The value of maintaining normothermia in patients undergoing abdominal surgery under general anesthesia is accepted. Three effective economical and practically applicable warming methods are combined body wrapping and heating blanket; combined body wrapping, heated moist dressings, and heating blanket; combined body wrapping, heated moist dressings, and warmed surgical rinse fluid, with or without heating blanket. These methods are practically applicable when low-cost method is indeed needed.     

Hypothermia in a surgical intensive care unit

Background

Inadvertent hypothermia is not uncommon in the immediate postoperative period and it is associated with impairment and abnormalities in various organs and systems that can lead to adverse outcomes. The aim of this study was to estimate the prevalence, the predictive factors and outcome of core hypothermia on admission to a surgical ICU.

Methods

All consecutive 185 adult patients who underwent scheduled or emergency noncardiac surgery admitted to a surgical ICU between April and July 2004 were admitted to the study. Tympanic membrane core temperature (Tc) was measured before surgery, on arrival at ICU and every two hours until 6 hours after admission. The following variables were also recorded: age, sex, body weight and height, ASA physical status, type of surgery, magnitude of surgical procedure, anesthesia technique, amount of intravenous fluids administered during anesthesia, use of temperature monitoring and warming techniques, duration of the anesthesia, ICU length of stay, hospital length of stay and SAPS II score. Patients were classified as either hypothermic (Tc ≤ 35°C) or normothermic (Tc> 35°C). Univariate analysis and multiple regression binary logistic with an odds ratio (OR) and its 95% Confidence Interval (95%CI) were used to compare the two groups of patients and assess the relationship between each clinical predictor and hypothermia. Outcome measured as ICU length of stay and mortality was also assessed.

Results

Prevalence of hypothermia on ICU admission was 57.8%. In univariate analysis temperature monitoring, use of warming techniques and higher previous body temperature were significant protective factors against core hypothermia. In this analysis independent predictors of hypothermia on admission to ICU were: magnitude of surgery, use of general anesthesia or combined epidural and general anesthesia, total intravenous crystalloids administrated and total packed erythrocytes administrated, anesthesia longer than 3 hours and SAPS II scores. In multiple logistic regression analysis significant predictors of hypothermia on admission to the ICU were magnitude of surgery (OR 3.9, 95% CI, 1.4–10.6, p = 0.008 for major surgery; OR 3.6, 95% CI, 1.5–9.0, p = 0.005 for medium surgery), intravenous administration of crystalloids (in litres) (OR 1.4, 95% CI, 1.1–1.7, p = 0.012) and SAPS score (OR 1.0, 95% CI 1.0–1.7, p = 0.014); higher previous temperature in ward was a significant protective factor (OR 0.3, 95% CI 0.1–0.7, p = 0.003). Hypothermia was neither a risk factor for hospital mortality nor a predictive factor for staying longer in ICU.

Conclusion

The prevalence of patient hypothermia on ICU arrival was high. Hypothermia at time of admission to the ICU was not an independent factor for mortality or for staying longer in ICU.     

术前口服碳水化合物对胃癌术后患者的影响

目的：研究胃癌患者术前口服碳水化合物的安全性及对术后胰岛素抵抗影响。方法：选取胃下部癌病理诊断明确的患者32例,取得知情同意后按照随机双盲的试验,参与者麻醉前2-3小时口服碳水化合物或安慰剂,术前4小时及术后即刻抽取静脉血测定血糖、胰岛素及C-反应蛋白浓度,通过HOMA发计算出术前术后胰岛素抵抗指数、胰岛素敏感指数、胰岛素分泌指数,并将两组进行比较。结果：与口服安慰剂组相比较,术前口服碳水化合物组的血糖、胰岛素、C-反应蛋白及胰岛素抵抗指数更低,且两组患者术后胰岛素敏感性均下降,但口服碳水化合物组的胰岛素敏感性较安慰剂组高。结论：术前2-3小时口服碳水化合物是安全有效的,且能明显术后即刻胰岛素抵抗状态,应作为术前常规处理。     

Changes in compliance predict pulmonary morbidity in patients undergoing abdominal plication.

The incidence and severity of the effects of pulmonary compliance changes were investigated in patients undergoing abdominal plication surgery. A total of 20 healthy adults scheduled for abdominal plication surgery who had no significant history of pulmonary disease and 20 adults scheduled for nonabdominal, nonthoracic surgery (control group) underwent general endotracheal anesthesia; neuromuscular blockade was confirmed with electrical twitch monitoring. Before abdominal plication, the mean airway compliance was measured under total neuromuscular blockade at 33.4 +/- 2.1 ml/cm water, which was not significant when compared with control patient values. After abdominal plication was performed, the mean airway compliance was remeasured under total neuromuscular blockade; it was significantly decreased at 24.0 +/- 1.8 ml/cm water when compared with values for control patients (32.6 +/- 1.6 ml/cm) and with preplication values. Patients with airway compliance changes of less than 4 ml/cm water (when compared with preplication pulmonary mechanics) had far less incidence of atelectasis, requirements for supplemental oxygen at 24 hours or longer, or hypoxia when compared with patients with compliance changes of greater than 4 ml/cm water. Patients with compliance changes greater than 9 ml/cm water had the highest incidence of pulmonary morbidity. These data suggest that significant changes in pulmonary compliance occur after abdominal plication and that these airway compliance changes are associated with a clinically increased incidence of pulmonary morbidity in the postoperative period.     

DNA damage in patients who underwent minimally invasive surgery under inhalation or intravenous anesthesia

Recent studies have demonstrated the genotoxicity of anesthetics in patients who have undergone surgery and in personnel who are occupationally exposed to anesthetics. However, these findings are controversial. Herein, we used the comet assay (single-cell gel electrophoresis) to investigate the genotoxic effects of two volatile compounds [isoflurane (ISF) and sevoflurane (SVF)] that are used in inhalation anesthesia, and of one intravenous (iv) anesthetic compound [propofol (PF)]. The groups consisted of 45 patients who underwent minimally invasive surgery that lasted at least 2h. Patients were classified as physical status I using the criteria of the American Society of Anesthesiologists (ASA) and were randomly allocated to receive ISF, SVF or PF anesthesia. Venous blood samples were collected at three time points as follows: before the premedication and the induction of anesthesia (T(0)); 2h after the beginning of anesthesia (T(1)); and on the day following surgery (T(2)). DNA damage (strand breaks and alkali-labile sites) was evaluated in peripheral blood lymphocytes. For each patient, one hundred nucleoids were analyzed per time point using a semi-automated image system. Patients did not differ with respect to their demographic characteristics, the duration of surgery, or the total doses of intraoperative drugs. The amount of DNA damage was not different among the three groups before anesthesia (T(0)). No statistically significant (p>0.05) increase in DNA damage was detected during (T(1)) or after anesthesia (T(2)) using three different protocols (ISF, SVF or PF). In conclusion, general anesthesia with inhaled ISF and SVF or iv PF did not induce DNA strand breaks or alkali-labile sites in peripheral lymphocytes. Therefore, our results show that the genotoxic risk of these anesthetics, for healthy patients undergoing minimally invasive otorhinological surgery, is low or even absent.     

Plasma and cerebrospinal fluid concentration of neuropeptide Y, serotonin, and catecholamines in patients under propofol or isoflurane anesthesia

Propofol is a widely used anesthetic for both induction and maintenance of anesthesia during surgery. A strong feeling of hunger has been reported during the early recovery period after propofol anesthesia. We have investigated the effect of propofol on appetite in 10 patients undergoing a craniotomy and in parallel measured neuropeptide Y (NPY), catecholamines, and serotonin levels in the cerebrospinal fluid and plasma during anesthesia. Ten patients anesthetized with a volatile agent (isoflurane) served as a control group. Plasma NPY and catecholamines levels were not affected by surgery at any time. We observed a strong increase in NPY concentrations in the cerebrospinal fluid independently of the anesthetic technique agent used, whereas catecholamines were unchanged. We found that serotonin concentrations decreased significantly in the plasma (but not in the cerebrospinal fluid) of patients treated by propofol when compared with the control group; this decrease was associated with an increase of hunger early postoperatively. We concluded that the proappetite effect of propofol is mediated through a decrease of serotonin at the peripheral level.     

右美托咪定在小儿气管异物取出术中的应用

目的：观察右美托咪定在气管异物取出术中对患儿呼吸、循环及术后恢复情况的影响。方法：40例行气管异物取出术患,随机分为右美托咪定组（D组）（n=20）和生理盐水组（S组）（n=20）,分别在麻醉诱导前10min静脉输注右美托咪定0.8μg/kg和等容量的生理盐水,输注时间为10min。术中高频射流呼吸机给氧,保持患儿自主呼吸,泵注丙泊酚和瑞芬太尼维持麻醉。结果：D组患儿术中屏气、咳嗽、喉痉挛、术中SP02〈90%显著低于S组（P〈0.05）;D组丙泊酚及瑞芬太尼用量减少（P〈0.05）。结论：在气管异物取出术中应用右美托咪定有很大的优势,对呼吸系统影响小,血流动力学平稳,术后并发症少。     

Diurnal beta-endorphin changes in human cerebrospinal fluid

Plasma and cerebrospinal fluid (CSF) beta-endorphin levels were determined by a RIA method in seven hydrocephalic male patients. The samples were simultaneously collected every two hours from 8 AM to 12 midnight and every hour from 1 AM to 7 AM. In both plasma and CSF beta-endorphin levels showed significant time-related variations during the 24 hour period. These results suggest the existence of diurnal CSF beta-endorphin variations analogous to those observed in plasma.     

Selection and care of cardiac patients for plastic surgery

A major operation after successful coronary artery bypass surgery has been proved as safe as an operation for a patient free from coronary artery disease. Most patients with angina who demonstrate an operable coronary lesion should usually be scheduled for coronary artery bypass before undergoing nonemergency surgery. It is advisable to postpone elective plastic surgery for 6 weeks to 3 months after coronary bypass and 6 months after myocardial infarction. The life expectancy of cardiac patients must be carefully considered before elective plastic surgery, because performing an operation on a patient who cannot live to enjoy the benefits is unwise. Working together, cardiac surgeons, cardiologists, and plastic surgeons can now prolong the quantity of life and enrich its quality in properly selected and carefully managed patients.     

术中不同速率输注右美托咪定在全凭静脉麻醉中的量效关系研究

目的：以脑电双频指数（bispectral index,BIS）作为麻醉镇静程度指标,探讨不同速率输注右美托咪定（dexmedetomidine,DEX）对全凭静脉麻醉中丙泊酚用量,术中重要时点血液动力学及麻醉恢复质量的影响。方法：选择拟于全麻下行妇科腹腔镜手术的患者60例（ASAI～II级）,根据DEX输注速率不同随机分为四组,即D1、D2、D3和D4组,每组15例,麻醉诱导前四组均给予负荷剂量DEX0．5μg·kg-1,10min输注完毕,继而四组分别以0．2、0．4、0．6和0．8μg·kg^-1·h^-1输注速度持续输注至冲洗腹腔。四组麻醉诱导方法相同,术中以BIS作为麻醉深度指标,根据BIS值调节丙泊酚血浆靶浓度维持麻醉。记录入室用药前（T0）、DEX负荷量输注后（T1）、气腹即刻（T2）、气腹后5min（T3）、气腹后30min（T4）、解除气腹后5min（T5）、拔喉罩即刻（T6）、拔喉罩后1min（T7）时收缩压（SBP）、舒张压（DBP）、心率（HR）、丙泊酚平均用量、苏醒时间、拔喉罩时间、拔喉罩后15rainOAA／s评分、术中及术后24小时内不良反应的发生情况。结果：①D2、D3、D4组丙泊酚平均用量较D1组明显减少（P〈0．05）,D3、D4组丙泊酚平均用量较D：组明显减少（P〈0．05）。D3、D4组间差异无统计学意义（P〉0．05）。②与T0比较,Tl～T2时四组SBP、DBP、HR降低（P〈0．05）,T3～T4时D3、D4组SBP、DBP、HR降低（P〈0．05）,D1、D2组SBP、DBP无明显变化（P〉0．05）,T5～T7时四组SBP、DBP、HR降低（P〈0．05）;D3、D4组在T3～T4时SBP、DBP较D1、D2组明显降低（P〈O．05）,D1、D2两组间差异无统计学意义（P〉0．05）,D3、D4两组间差异无统计学意义（P〉0．05）。③D4组苏醒时间、拔喉罩时间、较Dlq组明显延长（P〈0．05）,D4组OAA／s评分较D1-3组明显降低（P〈0．05）。④D4组使用阿托品次数较D1-3组明显增多（P〈0．05）,四组术中使用麻黄碱次数和术后24小时内恶心、呕吐、寒战差异无统计学差异（P〉0．05）。结论：在妇科腹腔镜手术中,DEX作为全身麻醉辅助用药,负荷剂量0．5μg·kg-1,术中持续输注速率0．4μg·kg-1·h-1可以有效降低丙泊酚用量,使围手术期的血流动力学保持平稳,不延长苏醒时间和拔喉罩时间,且不良反应更少,值得临床推广应用。     

The preoperative use of the relaxation response with ambulatory surgery patients

The efficacy of the regular elicitation of the relaxation response in reducing surgical anxiety and pain in an ambulatory surgery setting was studied in a population of patients scheduled for the surgical removal of a skin cancer. Forty-nine patients with skin cancer were enrolled in the study immediately after being informed of the ned for surgery; 21 of these patients elicited the relaxation response 20 minutes per day until the day of surgery, 21 read for 20 minutes per day, and 7 were noncompliant and were excluded from the study. Contrary to expectations, neither group of patients showed any increase in anxiety immediately before or after surgery on either psychological or physiological measures. Thus, there were no differences between the two groups on any of the psychological or physiological measures of anxiety, nor were there any differences in pain perception. There were statistically significant subjective differences; the experimental patients stated that the relaxation-response technique had reduced their anxiety several days before surgery and reportedly experienced their highest levels of anxiety prior to entering the study, while the controls experienced their highest levels of anxiety during and after surgery. This suggests that (1) minor outpatient surgery does not lead to detectable increased anxiety levels on the day of surgery and (2) regular elicitation of the relaxation response can alter subjective reports of distress associated with surgery.     

The respiratory change in preejection period: a new method to predict fluid responsiveness.

The accuracy and clinical utility of preload indexes as bedside indicators of fluid responsiveness in patients after cardiac surgery is controversial. This study evaluates whether respiratory changes (Delta) in the preejection period (PEP; DeltaPEP) predict fluid responsiveness in mechanically ventilated patients. Sixteen postcoronary artery bypass surgery patients, deeply sedated under mechanical ventilation, were enrolled. PEP was defined as the time interval between the beginning of the Q wave on the electrocardiogram and the upstroke of the radial arterial pressure. DeltaPEP (%) was defined as the difference between expiratory and inspiratory PEP measured over one respiratory cycle. We also measured cardiac output, stroke volume index, right atrial pressure, pulmonary arterial occlusion pressure, respiratory change in pulse pressure, systolic pressure variation, and the Deltadown component of SPV. Data were measured without positive end-expiratory pressure (PEEP) and after application of a PEEP of 10 cmH2O (PEEP10). When PEEP10 induced a decrease of >15% in mean arterial pressure value, then measurements were re-performed before and after volume expansion. Volume loading was done in eight patients. Right atrial pressure and pulmonary arterial occlusion pressure before volume expansion did not correlate with the change in stroke volume index after the fluid challenge. Systolic pressure variation, DeltaPEP, Deltadown, and change in pulse pressure before volume expansion correlated with stroke volume index change after fluid challenge (r2 = 0.52, 0.57, 0.68, and 0.83, respectively). In deeply sedated, mechanically ventilated patients after cardiac surgery, DeltaPEP, a new method, can be used to predict fluid responsiveness and hemodynamic response to PEEP10.