Incidence Of Severe Hypotension Research Articles

Effect of Dexmedetomidine on Intraoperative Hemodynamics and Blood Loss in Patients Undergoing Spine Surgery: A Systematic Review and Meta-Analysis

Objective Dexmedetomidine (Dex) is a highly selective α2 adrenoceptor agonist that reduces blood pressure and heart rate. However, its ability to provide stable hemodynamics and a clinically significant reduction in blood loss in spine surgery is still a matter of debate. This study aimed to investigate the effects of Dex on intraoperative hemodynamics and blood loss in patients undergoing spine surgery.Methods The Web of Science, MEDLINE, EMBASE, and the Cochrane Library were searched up to February 2023 for randomized controlled trials (RCTs) including patients undergoing spine surgeries under general anaesthesia and comparing Dex and saline. A fixed- or random-effect model was used depending on heterogeneity.Results Twenty-one RCTs, including 1388 patients, were identified. Dex added the overall risk of intraoperative hypotension (odds ratio [OR]: 2.11; 95% confidence interval [CI]: 1.24 - 3.58; P=0.006) and bradycardia (OR: 2.48; 95%CI: 1.57 - 3.93; P=0.0001). The use of a loading dose of Dex led to significantly increased risks of intraoperative hypotension (OR: 2.00; 95%CI: 1.06 - 3.79; P=0.03) and bradycardia (OR: 2.28; 95%CI: 1.42 - 3.66; P=0.0007). For patients receiving total intravenous anesthesia, there was an increased risk of hypotension (OR: 2.90; 95%CI: 1.24 - 6.82; P=0.01) and bradycardia (OR: 2.66; 95%CI: 1.53 - 4.61; P=0. 0005). For patients in the inhalation anesthesia group, only an increased risk of bradycardia (OR: 4.95; 95%CI: 1.41 - 17.37; P=0.01) was observed. No significant increase in the risk of hypotension and bradycardia was found in the combined intravenous-inhalation anesthesia group. The incidence of severe hypotension (OR: 2.57; 95%CI: 1.05 - 6.32; P=0.04), but not mild hypotension, was increased. Both mild (OR: 2.55; 95%CI: 1.06 - 6.15; P=0.04) and severe (OR: 2.45; 95%CI: 1.43 - 4.20; P=0.001) bradycardia were associated with a higher risk. The overall analyses did not reveal significant reduction in intraoperative blood loss. However, a significant decrease in blood loss was observed in total inhalation anesthesia subgroup (mean difference [MD]: -82.97; 95%CI: -109.04 - -56.90; P<0.001).Conclusions Dex increases the risks of intraoperative hypotension and bradycardia in major spine surgery. The administration of a loading dose of Dex and the utilization of various anesthesia maintenance methods may potentially impact hemodynamic stability and intraoperative blood loss.

The use of epinephrine infusion for the prevention of spinal hypotension during Caesarean delivery: A randomized controlled dose-finding trial

BackgroundThis study aimed to compare three epinephrine doses for the prevention of spinal hypotension during Caesarean delivery. MethodsThis randomized controlled trial included full-term pregnant women undergoing elective Caesarean delivery under spinal anesthesia. The participants received prophylactic epinephrine infusions at rates of 0.01, 0.02, or 0.03 mcg/kg/min. Spinal hypotension (systolic blood pressure <80% of baseline) was managed with a 9-mg ephedrine bolus. The primary outcome was the incidence of spinal hypotension. Secondary outcomes included total ephedrine requirement, the incidence of severe spinal hypotension, excessive tachycardia and hypertension, and neonatal outcomes. ResultsThe final analysis included 271 patients. The incidence of hypotension was lowest in the 0.03 mcg group (11/90 [12%]), followed by the 0.02 mcg (32/91 [35%]) and the 0.01 mcg (55/90 [61%]) groups (p < 0.001). The median ephedrine requirements (quartiles) were also the lowest in the 0.03 mcg group (0 [0−0] mg), followed by the 0.02 mcg (0 [0–9] mg) and the 0.01 mcg (9 [0–18] mg) groups. The incidence of severe hypotension was lower in the 0.03 mcg and 0.02 mcg groups than in the 0.01 mcg group (3/90 [3%], 5/91 [6%], and 15/90 [17%], respectively). The incidences of excessive tachycardia, hypertension, and neonatal outcomes were comparable among the groups. ConclusionThe use of epinephrine to prevent spinal hypotension during Caesarean delivery is feasible and effective. An initial dose of 0.03 mcg/kg/min produced the lowest incidence of hypotension compared to 0.02 mcg/kg/min and 0.01 mcg/kg/min doses. The three doses were comparable in terms of the incidence of tachycardia, hypertension, and neonatal outcomes. Study registrationClinicalTrials.gov Identifier: NCT05279703.

Colloid Preload versus Crystalloid Co-Load in the Setting of Norepinephrine Infusion during Cesarean Section: Time and Type of Administered Fluids Do Not Matter.

Background and Goal of Study: Spinal anesthesia for cesarean section is frequently associated with a high incidence of hypotension, which may bring about untoward effects for both the mother and fetus. Recently, norepinephrine has emerged as a promising alternative in maintaining blood pressure in the obstetric setting. Fluid administration is another technique still widely used to prevent maternal hypotension. The optimal fluid strategy to prevent maternal hypotension has not been elucidated yet. It has been recently suggested that the main strategy in the prevention and management of hypotension should be the combination of vasoconstrictive medications and fluid administration. The aim of this randomized study was to compare the incidence of maternal hypotension in parturients receiving either colloid preload or crystalloid co-load in the setting of prophylactic norepinephrine infusion during elective cesarean section under combined spinal-epidural anesthesia. Materials and Methods: After ethics committee approval, 102 parturients with full-term singleton pregnancies were randomly allocated to either 6% hydroxyethyl starch 130/0.4 5 mL/kg before the onset of spinal anesthesia (colloid preload group) or Ringer's lactate solution 10 mL/kg concurrent with the subarachnoid injection (crystalloid co-load group). In both groups, norepinephrine 4 μg/min starting simultaneously with the administration of the subarachnoid solution was also administered. The primary outcome of the study was the incidence of maternal hypotension, defined as systolic arterial pressure (SAP) <80% of baseline. The incidence of severe hypotension (SAP < 80 mmHg), total dose of vasoconstrictive agents administered, as well as the acid-base status and Apgar score of the neonate and any incidence of maternal side effects were also recorded. Results: Data analysis was performed on 100 parturients: 51 in the colloid preload group and 49 in the crystalloid co-load group. No significant differences were demonstrated between the colloid preload group and the crystalloid co-load group in the incidence of hypotension (13.7% vs. 16.3%, p = 0.933) or the incidence of severe hypotension (0% vs. 4%, p = 0.238). The median (range) ephedrine dose was 0 (0-15) mg in the colloid preload group and 0 (0-10) mg in the crystalloid co-load group (p = 0.807). The incidence of bradycardia, reactive hypertension, requirement for modification of vasopressor infusion, time to the first occurrence of hypotension, and maternal hemodynamics did not differ between the two groups. There were no significant differences in other maternal side effects or neonatal outcomes between groups. Conclusions: The incidence of hypotension with a norepinephrine preventive infusion is low and comparable with both colloid preload and crystalloid co-load. Both fluid-loading techniques are appropriate in women undergoing cesarean delivery. It appears that the optimal regimen for prevention of maternal hypotension is a combined strategy of a prophylactic vasopressor such as norepinephrine and fluids.

Effect of Fluid Bolus Administration on Cardiovascular Collapse Among Critically Ill Patients Undergoing Tracheal Intubation

Hypotension is common during tracheal intubation of critically ill adults and increases the risk of cardiac arrest and death. Whether administering an intravenous fluid bolus to critically ill adults undergoing tracheal intubation prevents severe hypotension, cardiac arrest, or death remains uncertain. To determine the effect of fluid bolus administration on the incidence of severe hypotension, cardiac arrest, and death. This randomized clinical trial enrolled 1067 critically ill adults undergoing tracheal intubation with sedation and positive pressure ventilation at 11 intensive care units in the US between February 1, 2019, and May 24, 2021. The date of final follow-up was June 21, 2021. Patients were randomly assigned to receive either a 500-mL intravenous fluid bolus (n = 538) or no fluid bolus (n = 527). The primary outcome was cardiovascular collapse (defined as new or increased receipt of vasopressors or a systolic blood pressure <65 mm Hg between induction of anesthesia and 2 minutes after tracheal intubation, or cardiac arrest or death between induction of anesthesia and 1 hour after tracheal intubation). The secondary outcome was the incidence of death prior to day 28, which was censored at hospital discharge. Among 1067 patients randomized, 1065 (99.8%) completed the trial and were included in the primary analysis (median age, 62 years [IQR, 51-70 years]; 42.1% were women). Cardiovascular collapse occurred in 113 patients (21.0%) in the fluid bolus group and in 96 patients (18.2%) in the no fluid bolus group (absolute difference, 2.8% [95% CI, -2.2% to 7.7%]; P = .25). New or increased receipt of vasopressors occurred in 20.6% of patients in the fluid bolus group compared with 17.6% of patients in the no fluid bolus group, a systolic blood pressure of less than 65 mm Hg occurred in 3.9% vs 4.2%, respectively, cardiac arrest occurred in 1.7% vs 1.5%, and death occurred in 0.7% vs 0.6%. Death prior to day 28 (censored at hospital discharge) occurred in 218 patients (40.5%) in the fluid bolus group compared with 223 patients (42.3%) in the no fluid bolus group (absolute difference, -1.8% [95% CI, -7.9% to 4.3%]; P = .55). Among critically ill adults undergoing tracheal intubation, administration of an intravenous fluid bolus compared with no fluid bolus did not significantly decrease the incidence of cardiovascular collapse. ClinicalTrials.gov Identifier: NCT03787732.

Colloid coload versus crystalloid coload to prevent maternal hypotension in women receiving prophylactic phenylephrine infusion during caesarean delivery: a randomised controlled trial

BackgroundThe optimal fluid strategy to prevent maternal hypotension during caesarean delivery remains unclear. This study aim was to compare the incidence of post-spinal anaesthesia hypotension in women receiving either colloid or crystalloid coload in the setting of prophylactic phenylephrine infusion during caesarean delivery. MethodsHealthy mothers undergoing elective caesarean delivery under spinal anaesthesia were randomised to receive a rapid intravenous coload with 6% hydroxyethyl starch 130/0.4 10 mL/kg (colloid group) or balanced crystalloid solution (Plasma Solution A) 10 mL/kg (crystalloid group) during spinal anaesthesia. All women had a prophylactic phenylephrine infusion initiated at 25 μg/min immediately after the subarachnoid block and titrated to systolic blood pressure using a standardised protocol. The primary outcome was the incidence of hypotension (systolic blood pressure <80% of baseline) until delivery. ResultsThe incidence of hypotension was 50% in the colloid group and 62% in the crystalloid group (absolute difference, −12% [95% CI −33% to 9%]; relative risk, 0.8 [95% CI 0.56 to 1.14]; P=0.314). No significant difference between groups was found in the number of hypotensive episodes (median 0.5 [IQR 0 to 1] vs 1 [0 to 2], P=0.132) or phenylephrine dose (675 [IQR 425 to 975] μg vs 750 [625 to 950] μg, P=0.109). The incidence of severe hypotension, symptomatic hypotension, bradycardia, nausea, and the neonatal outcomes were not significantly different. ConclusionsThis study found no benefit of colloid coload compared with crystalloid coload for preventing maternal hypotension in the presence of prophylactic phenylephrine infusion during caesarean delivery.

Incidence of accidental events during anesthesia from 2012 to 2016: survey on anesthesia-related events by the Japanese Society of Anesthesiologists

The Japanese Society of Anesthesiologists (JSA) has conducted surveys on life-threatening accidental events during anesthesia and reported results since 1992. This report describes the incidence of these life-threatening accidental events in the survey period between 2012 and 2016. JSA conducts an annual survey on accidental events. Each participating facility reports life-threatening accidental events that occurred each year. Facilities accredited by the JSA can electronically report events using the JSA Perioperative Information Management System (JSA-PIMS) software program that interfaces with the electronic anesthesia record system. The number of cardiac arrest events per 10,000 anesthesia cases gradually decreased from 2.97 in 2012 to 2.30 in 2016 (odds ratio OR 0.77 95% CI 0.68-0.88). The number of severe hypotension events per 10,000 anesthesia cases gradually decreased from 4.63 in 2012 to 4.24 in 2016 (OR 0.92, 95% CI 0.83-1.01). The number of severe hypoxia events per 10,000 anesthesia cases gradually decreased from 2.01 in 2012 to 1.59 in 2016 (OR 0.79, 95% CI 0.68-0.92). The number of life-threatening arrhythmia events per 10,000 anesthesia cases was 1.14 in 2012. Thereafter, it tended to decrease slightly to 0.88 in 2016 (OR 0.77, 95% CI 0.63-0.95). The incidence of cardiac arrest during this period was 2.63/10,000, which was lower the incidence reported in other countries. While no change was observed in the incidence of severe hypotension over the survey period, the incidence of severe hypoxia and life-threatening arrhythmia decreased by 20-25% during those 5years.

Impact of age, body mass index, and renal function for severe hypotension caused by oral 5-aminolevulinic acid administration in patients undergoing transurethral resection of bladder tumor.

Severe hypotension is a notable adverse event caused by administration of 5-aminolevulinic acid (5-ALA) during photodynamic diagnosis-assisted transurethral resection of bladder tumor (PDD-TURBT). Hypotension can be prolonged following induction of anesthesia and may require continuous administration of a vasopressor. Here, we investigated the risk factors for severe hypotension caused by oral administration of 5-ALA. A total of 128 patients with bladder tumors who underwent PDD-TURBT using 5-ALA were included in this study. Clinicopathological data were collected retrospectively and the correlations between the incidence of severe hypotension and clinicopathological factors were analyzed. Severe hypotension developed in 8 cases (6.3 %). Age ≥ 80 years, body mass index (BMI) ≥ 25 (kg/m2), and estimated glomerular filtration rate (eGFR) < 45 (mL/min/1.73 m2) were significantly correlated with severe hypotension (P = 0.003, 0.017, and 0.027, respectively). Severe hypotension developed in 1 of 89 cases (1.1 %) which have 0 or 1 risk factor, and in 3 of 31 cases (9.7 %) which have 2 risk factors, whereas it developed in 4 of 8 cases (50 %) which have all risk factors. Patients with all risk factors developed severe hypotension significantly more frequently compared with patients with 1 or fewer risk factors (P < 0.001). Age ≥ 80 years, BMI ≥ 25, and eGFR < 45 are risk factors for severe hypotension in PDD-TURBT using 5-ALA. The risk of developing severe hypotension is extremely high in patients who have all factors. Adjustment of the 5-ALA dose may be desirable in those patients.

Comparison of colloid preloading and continuous infusion of norepinephrine versus crystalloid co-loading and continuous infusion of norepinephrine in the prevention of maternal hypotension

Background and goal of study: Spinal anesthesia for cesarean section can be frequently complicated by hypotension, with untoward effects for both the mother and fetus. Recently, norepinephrine has been shown to be effective in maintaining blood pressure in obstetric patients. Another technique widely used to prevent hypotension is fluid administration. Current evidence suggests that the combination of fluid administration and vasoconstrictive medications should be the main strategy for prevention and management of hypotension. The aim of this randomized study was to investigate the combination of a norepinephrine infusion and colloid preloading versus the combination of a norepinephrine infusion and crystalloid co-loading for the prevention of maternal hypotension during elective cesarean section under combined spinal-epidural anaesthesia Materials and methods: One hundred parturients were randomized to receive either 6% hydroxyethyl starch 130/0.4 5 mL/kg before spinal anesthesia (colloid preload) or Ringer’s Lactate solution 10 mL/kg starting with intrathecal injection (crystalloid co-load). Both groups were also administered norepinephrine 4 μg/min, starting simultaneously with the administration of the subarachnoid solution. The primary outcome was the incidence of maternal hypotension (SBP <80% of baseline). The incidence of severe hypotension (SAP <80 mmHg), total dose of ephedrine administered as well as maternal side-effects and the acid-base status and Apgar score of the neonate were also recorded Results: There were no significant differences in the incidence of hypotension (13.7% vs. 16.3%, P = 0.933 or severe hypotension (0% vs. 4%, P = 0.238) between colloid preload and crystalloid co-load groups, respectively. The median [range] ephedrine dose was 0 [0–15] mg in the colloid preload group and 0 [0–10] mg in the crystalloid co-load group (P = 0.807). There were no significant differences in maternal side-effects or neonatal outcomes between groups Conclusion: The incidence of hypotension during elective cesarean section is low and comparable when a norepinephrine infusion is used in combination with either colloid preload or crystalloid co-load, with perhaps a marginal superiority of colloid preload in the prevention of severe hypotension. It appears that the optimal regimen for prevention of maternal hypotension is a combination of fluids and a prophylactic vasopressor like norepinephrine.

Hypobaric Unilateral Spinal Anaesthesia versus General Anaesthesia in Elderly Patients Undergoing Hip Fracture Surgical Repair: A Prospective Randomised Open Trial.

Intraoperative hypotension during hip fracture surgery is frequent in the elderly. No study has compared the haemodynamic effect of hypobaric unilateral spinal anaesthesia (HUSA) and standardised general anaesthesia (GA) in elderly patients undergoing hip fracture surgical repair. We performed a prospective, randomised open study, including 40 patients aged over 75 years, comparing the haemodynamic effects of HUSA (5 mg isobaric bupivacaine with 5 μg sufentanil and 1 mL sterile water) and GA (induction with etomidate/remifentanil and maintenance with desflurane/remifentanil). An incidence of severe hypotension, defined by a decrease in systolic blood pressure of >40% from baseline, was the primary endpoint. The incidence of severe hypotension was lower in the HUSA group compared with that in the GA group (32% vs. 71%, respectively, p=0.03). The median [IQR] ephedrine consumption was lower (p=0.001) in the HUSA group (6 mg, 0-17 mg) compared with that in the GA group (36 mg, 21-57 mg). Intraoperative muscle relaxation and patients' and surgeons' satisfaction were similar between groups. No difference was observed in 5-day complications or 30-day mortality. This study shows that HUSA provides better haemodynamic stability than GA, with lower consumption of ephedrine and similar operating conditions. This new approach of spinal anaesthesia seems to be safe and effective in elderly patients undergoing hip fracture surgery.

Prophylactic Phenylephrine Infusions to Reduce Severe Spinal Anesthesia Hypotension During Cesarean Delivery in a Resource-Constrained Environment.

Phenylephrine infusions are considered as standard management for obstetric spinal hypotension, but there remains reluctance to implement them in resource-limited contexts. This prospective, alternating intervention study of patients undergoing elective or urgent cesarean delivery under spinal anesthesia compared a vasopressor bolus strategy to fixed-rate, low-dose prophylactic phenylephrine infusion with supplemental boluses. The primary outcome was the incidence of severe hypotension (mean arterial pressure <70% baseline or systolic blood pressure <80 mm Hg). Fewer patients receiving prophylactic phenylephrine infusions had severe hypotension (47.4% [n = 120/253] vs 62.1% [n = 157/253], P = .001, estimated relative risk 0.84, 95% confidence interval, 0.69-1.02), with no significant difference in the rate of hypertension (15% [n = 39/253] vs 11% [n = 27/253], P = .11, estimated relative risk 1.39, confidence interval 0.87-2.20). Guidelines for resource-constrained settings should consider a fixed, low-dose phenylephrine infusion in combination with rescue vasopressor bolus therapy.

Study of prevention and control of delirium in ventilated patients by simulating blockage of circadian rhythm with sedative in intensive care unit

To explore the effect of giving sedatives according to the circadian rhythm in prevention of occurrence of delirium and the prognosis of patients undergoing mechanical ventilation in intensive care unit (ICU). A prospective double-blinded randomized controlled trial (RCT) was conducted. The patients admitted to Department of Critical Care Medicine of the Second Hospital of Lanzhou University from July 2014 to February 2015, undergoing invasive mechanical ventilation over 12 hours were enrolled. All the patients were given fentanyl for analgesia, and they were randomly divided into simulated circadian clock group (study group, n = 35) and non-simulated circadian clock group (control group, n = 35). The patients in each group were subdivided into three subgroups according to the kinds of sedative drugs, namely dexmedetomidine group (n = 8), propofol group (n = 14), and dexmedetomidine combined with propofol group (combination group, n = 13). Visual analogue scale (VAS) standard and Richmond agitation-sedation scale (RASS) were used to control the analgesic and to quantify the depth of sedation by titrating the dose of sedative drugs, the simulated circadian clock was set to control the RASS score at 0-1 during the day, and -1 to -2 at night in study group. The RASS score in the control group was set at -1 to -2 day and night. The urine 6-hydroxy acid melatonin (aMT6s) levels at different time points in the first diurnal rhythm (06:00, 12:00, 18:00, 24:00) were determined by enzyme linked immunosorbent assay (ELISA). The incidence of delirium, severe hypotension, severe bradycardia and other adverse reactions, duration of mechanical ventilation and the time of extubation, length of ICU stay, amount of sedative and analgesic drugs used were recorded. The correlation between delirium and other indexes was analyzed by using Spearman correlation analysis. (1) There were no significant differences in gender, age, acute physiology and chronic health evaluation II (APACHEII) score among groups. (2) Urine aMT6s levels did not show circadian rhythm in both groups, aMT6s level at 06:00 in study group showed an increasing tendency as compared with the control group, but the difference was not statistically significant. (3) Compared with the control group, the incidence of delirium was significantly lowered in the study group (14.3% vs. 37.1%, P = 0.029), but no significant differences were found in the incidence of severe hypotension or severe bradycardia (20.0% vs. 25.7%, 11.4% vs. 20.0%, both P > 0.05). In simulated circadian clock group, the incidence of delirium in dexmedetomidine group was significantly lower than that of the propofol group (6.3% vs. 32.1%, P < 0.05). (4) Compared with control group with the same sedative, the duration of mechanical ventilation, extubation time, length of ICU stay were significantly shortened, and the dosage of sedative drugs used was reduced in study group (all P < 0.05). In simulated circadian clock group, the duration of mechanical ventilation in dexmedetomidine group was significantly shorter than that of propofol group and combination group (hours: 75.75±26.78 vs. 102.00±26.31 and 100.31±25.38, both P < 0.05), and the length of ICU stay was significantly shorter than that of propofol group (days: 5.75±1.04 vs. 7.00±1.52, P < 0.05). (5) The occurrence of delirium was positively correlated with duration of mechanical ventilation (r = 0.705), extubation time (r = 0.704), length of ICU stay (r = 0.666, all P = 0.000), and no correlation was found between the occurrence of delirium and aMT6s level at 06:00, 12:00, 18:00, and 24:00 (r = -0.135, r = 0.163, r = 0.269, r = -0.077, all P > 0.05). Administration of sedatives according to simulating circadian time could decrease the duration of mechanical ventilation, extubation time, and the length of ICU stay, decrease the dosage of sedative drugs, and reduce the incidence of delirium. Dexmedetomidine could reduce the incidence of delirium, and improve the prognosis of patients.

Protamine adverse reactions in NPH insulin treated diabetics undergoing coronary artery bypass grafting

Background The routine use of protamine in cardiac surgery to neutralize heparin is usually associated with systemic reactions that result in substantial morbidity and mortality. Aim This study aimed to investigate the relationship between neutral protamine Hagedorn (NPH) insulin use and severe adverse reactions to intravenous protamine given after cardiopulmonary bypass. Methods After obtaining hospital ethics committee approval and after obtaining informed consent, 100 patients between 45 and 70 years of age of American Society of Anesthesiologist physical status II–III undergoing elective primary isolated coronary artery bypass grafting were included in this prospective study, which was conducted between May 2013 and June 2014. Patients were divided into two groups: the NPH group (50 patients), which included patients who were on NPH insulin preparation for more than 5 years before the study, and the non-NPH group (50 patients), which included patients on oral hypoglycemics. The incidence of protamine reactions was recorded for 30 min after protamine infusion. The incidence of severe hypotension, increased airway pressure, and cardiac arrest were compared using the χ2-test. A P value less than 0.05 was considered significant. Results All patients (50 in each group) completed the study. There was no significant difference in patients’ demographic data, preoperative comorbidities, and surgical factors between the two study groups. The number of patients who had hypotension was significantly higher in the NPH insulin group compared with the non-NPH group. For both groups, there was no significant difference with respect to bronchospasm, cardiac arrest, and increased pulmonary artery pressure. Conclusion This prospective study showed increased risk for hypotension among patients receiving NPH insulin for more than 5 years compared with those who were not exposed to NPH insulin.

A Randomized Trial Comparing Colloid Preload to Coload During Spinal Anesthesia for Elective Cesarean Delivery

Hypotension after spinal anesthesia for cesarean delivery is common. Previous studies have demonstrated that a crystalloid fluid "coload" (rapid administration of a fluid bolus starting at the time of intrathecal injection) is superior to the conventional crystalloid preload (fluid administered before the intrathecal injection) for preventing hypotension. Colloid preload provides a sustained increase in central blood volume. We hypothesized that, in contrast to crystalloid, a colloid preload may be more effective than colloid coload for reducing the incidence of spinal anesthesia-induced hypotension. In this double-blind study, 178 patients were randomly assigned to receive a preload of 500 mL of hydroxyethyl starch over a period of 15-20 min before initiation of spinal anesthesia (n = 90) or an identical fluid bolus of hydroxyethyl starch starting at the time of identification of cerebrospinal fluid (n = 88). Vasopressors (ephedrine or phenylephrine) were administered if systolic arterial blood pressure decreased less than 80% of the baseline pressure and <100 mm Hg, or with smaller decreases in blood pressure if accompanied by nausea, vomiting, or dizziness. The primary outcome was the incidence of hypotension (defined as the administration of at least one dose of vasopressor). There was no significant difference between the groups in the incidence of hypotension (68% in preload group and 75% in coload group, 95% confidence interval of difference -6%-20%; P = 0.28), doses of ephedrine and phenylephrine, and number of vasopressor unit doses. The incidence of severe hypotension (systolic blood pressure <80 mm Hg) was 16% in the preload group and 22% in the coload group (P = 0.30). There were no differences in the incidence of nausea and/or vomiting, or neonatal outcome between the groups. There was no difference in the incidence of hypotension in women who received colloid administration before the initiation of spinal anesthesia compared with at the time of initiation of anesthesia. Both modalities are inefficient as single interventions to prevent hypotension.

Angiotensin System Inhibitors in a General Surgical Population

We studied the relationship between the timing of discontinuing chronic angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II receptor subtype 1 antagonists (ARA) and hypotension after the induction of general anesthesia in a general surgical population. We retrospectively studied 267 hypertensive patients receiving chronic ACEI/ARA therapy undergoing elective noncardiac surgery under general anesthesia. During preoperative visits, patients were asked to either take their last ACEI/ARA therapy on the morning of surgery or withhold it up to 24 h before surgery. The number of hours from the last ACEI/ARA dose to surgery was recorded during the preoperative interview. Electronic medical and anesthesia records were reviewed for comorbidities, type and dose of anesthetics used, intraoperative hemodynamics, IV fluids, perioperative vasopressor administration, and rate of severe postoperative complications. Arterial blood pressure (BP) and heart rate were recorded during the 60-min postinduction period, and hypotension was classified as moderate (systolic BP <or=85 mm Hg) and severe (systolic BP <or=65 mm Hg). We analyzed all variables separately for patients who took their last ACEI/ARA therapy <10 h and >or=10 h before surgery. During the first 30 min after anesthetic induction, moderate hypotension was more frequent in patients whose most recent ACEI/ARA therapy was taken <10 h (60%) compared with those who stopped it >or=10 h (46%) before induction (P = 0.02). The adjusted odds ratio for moderate hypotension was 1.74 (95% confidence interval, 1.03-2.93) for those who took their ACEI/ARA therapy <10 h before surgery (P = 0.04). There were no differences between groups in the incidence of severe hypotension, nor was there a difference in the use of vasopressors. During the 31-60 min after induction, the incidence of either moderate (P = 0.43) or severe (P = 0.97) hypotension was similar in the two groups. No differences in postoperative complications were found between groups. In conclusion, discontinuation of ACEI/ARA therapy at least 10 h before anesthesia was associated with a reduced risk of immediate postinduction hypotension.

Double-blind comparison between zofenopril and lisinopril in patients with acute myocardial infarction: Results of the Survival of Myocardial Infarction Long-term Evaluation-2 (SMILE-2) study

Background Angiotensin-converting enzyme (ACE) inhibitors have been reported to be effective in placebo-controlled trials in various subsets of patients with acute myocardial infarction (MI). However, no direct comparisons have been performed between different ACE inhibitors in the same patient population. Methods This phase III, double-blind, parallel-group, multicenter study compared the safety and efficacy of zofenopril and lisinopril in 1024 thrombolyzed patients with acute MI. Patients, aged 18 to 75 years, were randomized to receive oral zofenopril (30-60 mg/day) or lisinopril (5-10 mg/day), starting within 12 hours of completion of thrombolytic therapy and continuing for 42 days. The primary study end point was the incidence of severe hypotension (systolic blood pressure <90 mm Hg), either cumulative or drug-related. Secondary end points included additional safety and efficacy parameters. Results The overall incidence of severe hypotension was slightly 5more reduced with zofenopril (10.9%) than with lisinopril (11.7%, P = .38). The incidence of drug-related severe hypotension was slightly but significantly lower with zofenopril than with lisinopril (6.7 vs 9.8%, 2-tailed P = .048). The 6-week mortality rate was 3.2% in the zofenopril group and 4.0% in the lisinopril group ( P = .38), and no significant differences were observed in the incidence of major cardiovascular complications or any safety variables between the 2 ACE inhibitors. Conclusions The SMILE-2 study demonstrates that both zofenopril and lisinopril are safe and associated with a rather low rate of severe hypotension when given in accordance with a dose-titrated scheme to thrombolyzed patients with acute MI. These findings could have a positive clinical impact and increase the proportion of patients with acute MI who can be safely treated with ACE inhibitors. (Am Heart J 2003;145:80-7.)