Evaluation of pre-induction dynamic arterial elastance as an adjustable predictor of post-induction hypotension: A prospective observational study

Study objectiveDynamic arterial elastance (Eadyn) has been suggested as a functional measure of arterial load. We aimed to evaluate whether pre-induction Eadyn can predict post-induction hypotension.DesignProspective observational study.PatientsAdult patients undergoing general anesthesia with invasive and non-invasive arterial pressure monitoring systems.MeasurementsWe collected invasive and non-invasive Eadyns (n = 38 in each), respectively. In both invasive and non-invasive Eadyns, pre-induction Eadyns were obtained during one-minute tidal and deep breathing in each patient before anesthetic induction. Post-induction hypotension was defined as a decrease of >30% in mean blood pressure from the baseline value or any absolute mean blood pressure value of <65 mmHg for 10 min after anesthetic induction. The predictabilities of Eadyns for the development of post-induction hypotension were tested using receiver-operating characteristic curve analysis.Main resultsInvasive Eadyn during deep breathing showed significant predictability with an area under the curve (AUC) of 0.78 (95% Confidence interval [CI], 0.61–0.90, P = 0.001). But non-invasive Eadyn during tidal breathing (AUC = 0.66, 95% CI, 0.49–0.81, P = 0.096) and deep breathing (AUC = 0.53, 95% CI, 0.36–0.70, P = 0.75), and invasive Eadyn during tidal breathing (AUC = 0.66, 95% CI, 0.41–0.74, P = 0.095) failed to predict post-induction hypotension.ConclusionIn our study, invasive pre-induction Eadyn during deep breathing -could predict post-induction hypotension. Despite its invasiveness, future studies will be needed to evaluate the usefulness of Eadyn as a predictor of post-induction hypotension because it is an adjustable parameter.     

An observational study of skin conductance monitoring as a means of predicting hypotension from spinal anaesthesia for caesarean delivery

BackgroundHypotension after spinal anaesthesia is a common and important complication at caesarean delivery. Skin conductance monitoring has been shown to predict post-spinal hypotension in elderly patients and may be a rapid, non-invasive means of predicting risk in the obstetric population.MethodsWomen having elective caesarean delivery were included in this observational pilot trial. Baseline data were obtained for blood pressure, heart rate and skin conductance variables before administration of spinal anaesthesia and at 1-min intervals for 20 min thereafter. Correlations between baseline data and minimum post-spinal blood pressure were calculated, and the predictive value of baseline variables was estimated by use of receiver operator characteristics.ResultsForty women completed the study. Spinal anaesthesia was followed in most cases by a significant reduction from baseline in systolic blood pressure [0–9% n = 2 (5%), 10–20% n = 21 (52.5%), 20–30% n = 12 (30%), >30% n = 5 (12.5%)]. Minimum systolic blood pressure was >100 mmHg in 25 (62%), 80–100 mmHg in 12 (30%) and <80 mmHg in 3 (7.5%) patients. Fasting times, spinal block distribution, baseline heart rate, blood pressure or baseline skin conductance did not predict post-spinal hypotension or neonatal outcome.ConclusionIn contrast to a previous report in elderly patients, we were unable to demonstrate a significant relationship between baseline sympathetic tone, measured by skin conductance, and hypotension following spinal anaesthesia in women undergoing elective caesarean delivery.     

The impact of fluid optimisation before induction of anaesthesia on hypotension after induction

Intra-operative hypotension is a known predictor of adverse events and poor outcomes following major surgery. Hypotension often occurs on induction of anaesthesia, typically attributed to hypovolaemia and the haemodynamic effects of anaesthetic agents. We assessed the efficacy of fluid optimisation for reducing the incidence of hypotension on induction of anaesthesia. This prospective trial enrolled 283 patients undergoing radical cystectomy and randomly allocated them to goal-directed fluid therapy (n = 142) or standard fluid therapy (n = 141). Goal-directed fluid therapy patients received fluid optimisation based on stroke volume response to passive leg raise before induction; those with positive passive leg raise received intravenous crystalloid fluid boluses until stroke volume was optimised. Baseline mean arterial pressure was measured on the morning of surgery and on arriving in the operating theatre. This post-hoc analysis defined haemodynamic instability as either a > 30% relative drop in mean arterial pressure compared with baseline or absolute mean arterial pressure < 55 mmHg, within 15 min of induction. Forty-two (30%) goal-directed fluid therapy patients underwent fluid optimisation after finding an intravascular fluid deficit via passive leg raise testing; 106 (75%) goal-directed fluid therapy and 112 (79%) standard fluid therapy patients met criteria for haemodynamic instability. There was no significant difference in the incidence of haemodynamic instability between the goal-directed fluid therapy and standard fluid therapy groups using absolute mean arterial pressure drop below 55 mmHg (p = 0.58) or using pre-surgical testing or pre-surgical mean arterial pressure values as baseline (p = 0.21, p = 0.89, respectively); however, the difference in the incidence of haemodynamic instability was significant using the operating theatre baseline mean arterial pressure (p = 0.004). We conclude that fluid optimisation before induction of general anaesthesia did not significantly impact haemodynamic instability.     

Time course of increased haemodilution in hypotension induced by extradural anaesthesia

Volume loading with crystalloid solution results in more pronounced haemodilution in patients who develop arterial hypotension during induction of extradural anaesthesia than in those who remain normotensive. The aim of this study was to describe the time course of this increase in haemodilution. Heart rate, systolic arterial pressure and blood haemoglobin concentration were measured every 3 min during the onset of extradural anaesthesia in 22 elderly men undergoing short urological operations. Fluid therapy consisted of 15 ml/kg body weight of Ringer's acetate solution. Patients with a decrease in systolic pressure of > 25% retained 50% (SD 12%) of the infused fluid in the circulation, while the others retained 36 (8%) (P < 0.002). In both groups, arterial hypotension was followed by increased haemodilution after a delay of as much as 15 min. This suggests that, despite volume loading, there is relative hypovolaemia throughout the development of hypotension.      

Maternal cardiovascular consequences of positioning after spinal anaesthesia for Caesarean section: left 15 degree table tilt vs. left lateral

Sixty healthy women undergoing elective Caesarean section were randomly allocated to either a measured 15 degrees left table tilt position (n = 31) or full left lateral position (n = 29) for a 15-min period after spinal blockade. Arm and leg blood pressure, ephedrine requirements, symptoms, fetal heart rate, cord gases and Apgar scores were recorded. Mean ephedrine requirements and incidence of hypotension were similar in the two groups. Arm systolic arterial pressure over time was similar in both groups, but leg systolic arterial pressure over time was significantly lower in the tilt group (p < 0.001); the mean leg systolic arterial pressure was lower for all 15 sequential recordings in the tilt group, reaching statistical significance (p < 0.05) at 4, 5, 6 and 8 min. Differences in maternal nausea, vomiting and bradycardia and fetal outcome were not statistically significant. Following spinal anaesthesia, even a true 15 degrees left table tilt position is associated with aortic compression.     

Prevention of spinal anaesthesia-induced hypotension in the elderly: i.m. methoxamine or combined hetastarch and crystalloid

We have compared two methods of reducing hypotension during spinal anaesthesia in elderly patients, 6% hetastarch and crystalloid or methoxamine 10 mg i.m., in terms of haemodynamic stability and requirements for additional vasopressors. Sixty-two patients (aged 60- 97 yr) undergoing surgical fixation of fractured neck of femur were allocated randomly to receive 6% hetastarch (Hespan) 500 ml followed by Hartmann's solution 500 ml (group HS, n = 32) or a bolus injection of methoxamine 10 mg i.m. (group MX, n = 30), 10 min before induction of spinal anaesthesia with 0.5% hyperbaric bupivacaine 2.25-3.0 ml. Arterial pressure was measured non-invasively by an oscillotonometer at 2-min intervals from 0 to 40 min and at 5-min intervals thereafter. Methoxamine 2 mg i.v. was given if systolic arterial pressure (SAP) decreased to < 100 mm Hg. Hypotension was defined as a 25% decrease from baseline SAP or mean arterial pressure (MAP). Patient data, sensory level and blood loss were similar in the two groups. SAP and MAP increased initially from baseline until induction of spinal anaesthesia and then decreased for 30 min in both groups, but remained higher in group MX (P < 0.05). Heart rate (HR) decreased from baseline in group MX (P < 0.05) and was less than in group HS at all times from 2 to 60 min (P < 0.01). The incidence of SAP hypotension (47% vs 75%; P = 0.03, odds ratio (OR) = 3.43) and MAP hypotension (47% vs 67%; P = 0.09, OR = 2.51) was less in group MX than in group HS. Requirements for rescue methoxamine i.v. (27% vs 53%, P = 0.04, OR = 3.11) was less in group MX than in group HS but the dose of rescue methoxamine given (mean 6.3 (95% confidence intervals 3.0-9.6) vs 8.9 (5.6-12.2) mg) and time to onset of hypotension (20.7 (14.5-26.7) vs 17.3 (11.4-23.1) min) were similar in groups MX and HS, respectively. We conclude that methoxamine 10 mg i.m., given 10 min before induction of spinal anaesthesia in normovolaemic elderly patients, reduced subsequent SAP and MAP hypotension, HR and requirements for rescue vasopressor therapy compared with a combination of 6% hetastarch 500 ml and crystalloid 500 ml. The previously reported benefit of such volume administration may not extend to the elderly.      

Spinal-induced hypotension in elderly patients with hip fracture. A comparison of glucose-free bupivacaine with glucose-free bupivacaine and fentanyl

Intraoperative hypotension is a common and potentially deleterious event in elderly patients undergoing spinal anaesthesia for repair of hip fractures. The synergism between intrathecal opioids and local anaesthetics may allow a reduction in the dose of local anaesthetic and cause less sympathetic block and hypotension, while still maintaining adequate anaesthesia. We studied 40 elderly patients having either an insertion of a dynamic hip screw or a hemiarthroplasty and compared 9.0 mg glucose-free bupivacaine with added fentanyl 20 microg (group BF) with 11.0 m glucose-free bupivacaine alone (group B). Hypotension was defined as a fall in systolic blood pressure to less than 75% baseline or less than 90 mmHg. The incidence and frequency of hypotension in group BF were less than in group B. Similarly, falls in systolic, diastolic and mean blood pressures were all less in group BF than in group B. However, there were four failed blocks in group BF and one in group B.     

The circulatory responses to fibreoptic intubation: a comparison of oral and nasal routes

The circulatory responses to fibreoptic intubation under general anaesthesia were studied in 60 adult female patients who were randomly assigned to receive either the oral or nasal route for insertion. Non-invasive blood pressure and heart rate were recorded before anaesthesia induction (baseline values), immediately after anaesthesia induction (post-induction values), at intubation and every minute for a further 5 min. The product of heart rate and systolic blood pressure (rate pressure product) at every time point was also calculated. The results showed that both fibreoptic orotracheal intubation and fibreoptic nasotracheal intubation resulted in significant increases in blood pressure, heart rate and rate pressure product compared to baseline and post-induction values. The times required to reach the maximum values of systolic blood pressure and heart rate were significantly longer in the fibreoptic nasotracheal intubation group than in the fibreoptic orotracheal intubation group. There were no significant differences between the two groups in blood pressure, heart rate and rate pressure product at any measuring point, or in the maximum values during observation. The time required for recovery of systolic blood pressure to the post-induction value was not significantly different between the two groups, but the time required for recovery of heart rate to post-induction value was significantly longer in the fibreoptic orotracheal intubation group than in the fibreoptic nasotracheal intubation group. It was concluded that both fibreoptic orotracheal and fibreoptic nasotracheal intubations could cause a similar magnitude of circulatory responses in general anaesthetised, female adults, but the tachycardic response to fibreoptic orotracheal intubation lasted longer than that to fibreoptic nasotracheal intubation.     

A comparison of the haemodynamic effects of lateral and sitting positions during induction of spinal anaesthesia for caesarean section

BackgroundHypotension during spinal anaesthesia occurs commonly in parturients. By influencing spread of local anaesthetic, maternal position may affect the speed of onset of sensory block and thus the haemodynamic effects. The aim of this study was to determine whether inducing spinal anaesthesia for caesarean section using plain bupivacaine in the lateral position would result in less hypotension compared with the sitting position.MethodsOne hundred American Society of Anesthesiologists physical status I and II patients undergoing elective caesarean section were randomised to receive spinal anaesthesia in the lateral position (Group L) or the sitting position (Group S). Using the L3-4 interspace, patients received intrathecal plain bupivacaine, 10 mg or 12 mg according to their height, after which they were placed immediately in the supine position with left uterine displacement. Maternal blood pressure was measured every minute for 10 min, every three min for 20 min and 5-minutely thereafter. Hypotension was defined as a fall in systolic blood pressure >20% or a value <90 mmHg.ResultsThere was no difference in the lowest recorded systolic blood pressure in Group L (99.2 ± 8.9 mmHg) compared with Group S (95.4 ± 12.3 mmHg, P = 0.081). However, the lowest recorded mean arterial pressure was greater in Group L (72.9 ± 11.2 mmHg) than in Group S (68.2 ± 9.6 mmHg; P = 0.025). The incidence of hypotension was lower in Group L (17/50, 34%) than in Group S (28/50, 56%; P = 0.027). Onset of hypotension was similar between groups.ConclusionHypotension occurred less frequently when spinal anaesthesia for caesarean using plain bupivacaine was induced with patients in the lateral compared with the sitting position. Values for the lowest recorded mean arterial pressure were greater but values for the lowest recorded systolic blood pressure were similar for patients in the lateral position group.     

Hypotension in elderly patients undergoing spinal anaesthesia for repair of fractured neck of femur. A comparison of two different spinal solutions.

Intraoperative hypotension is a common and sometimes deleterious event in elderly patients undergoing spinal anaesthesia for repair of hip fractures. The synergism between intrathecal opioids and local anaesthetics may allow a reduction in the dose of local anaesthetic and reduce hypotension, while still maintaining adequate anaesthesia. We studied 42 elderly patients having insertion of a Richards pin and plate and compared 7.5 mg hyperbanic bupivacaine with added fentanyl 20 microg (group BF) to 12.5 mg hyperbaric bupivacaine alone (group B). Hypotension was defined as a fall in systolic blood pressure to less than 75% baseline or less than 90 mmHg and occurred with an overall incidence of 59.5%. There was no difference in the incidence or severity of hypotension between the two groups. Two patients from group B and one from group BF experienced mild discomfort. Pruritus was more common in group BF.     

General anaesthesia versus combined spinal epidural anaesthesia in the presence of mild to moderate pericardial effusion: A study of volunteers undergoing caesarean section

Study objectiveThis study evaluated the haemodynamic effects of general anaesthesia versus combined spinal epidural anaesthesia in patients undergoing caesarean section in the presence of mild to moderate pericardial effusion.DesignA prospective randomized study.SettingThe study setting included a hospital where a surgical team performed elective caesarean section in the presence of mild to moderate pericardial effusion.Patients and interventionsThirty healthy patients were randomly divided into two groups, general anaesthesia (GA) (group I) and combined spinal epidural (CSE) anaesthesia (group II).Measurements and main resultsHeart rate, central venous pressure, mean arterial blood pressure, and pulmonary capillary wedge pressure were measured 10 min before anaesthesia, after 20 and 30 min of anaesthesia, and 30 min after recovery. Blood loss was significantly lower in group II [465.33 (72.78) ml] as compared to group I [548.20 (22.73) ml]. The pain score in group II was significantly lesser [1.66 (0.72)], than in group I [2.60 (0.73)]. The HR was significantly higher in group I as compared to that in group II at 20 and 30 min after anaesthesia, and 30 min after surgery, being 81.53 (2.72), 94.80 (3.12) and 82.8 (2.85) (beats/min), respectively. However, the CVP was significantly higher in the group I at 20 and 30 min after induction, being 8.40 (0.63) and 7.80 (0.67) (cmH2O) respectively. The MAP was significantly higher in group II than in group I at 20 and 30 min after induction, being 80.86 (1.30) and 81.00 (1.00) (mmHg) respectively. The PCWA was significantly higher in group I compared to group II at 20 and 30 min after induction, being 10.13 (1.35) and 11.80 (0.94) (mmHg), respectively.ConclusionCSE anaesthesia appeared to be more advantageous, in patients undergoing caesarean section with mild to moderate pericardial effusion, with less haemodynamic changes, decreased blood loss, and better postoperative analgesia than general anaesthesia patients.     

Single shot spinal anaesthesia with hypobaric bupivacaine for hip fracture repair surgery in the elderly. Randomized,double blinded comparison of 3.75 mg vs. 7.5 mg

BackgroundArterial hypotension is the most frequent adverse effect of subarachnoid anaesthesia in the elderly sustaining a femoral proximal fracture. Decreasing the local anaesthetic dose reduces the incidence of hypotension but shortens sensory block duration that could be insufficient in some surgical procedures. Sensory block duration could be prolonged using hypobaric local anaesthetics. We evaluated whether low hypobaric bupivacaine doses were adequate for this type of surgery while maintaining the haemodynamic stability.MethodsA prospective, randomized, double blinded study was designed. Patients over 65 years old, sustaining traumatic hip fracture, were assigned to one of two groups: B0.5 group, hypobaric bupivacaine 7.5 mg 5 mg/ml (control group), and B0.25 group, hypobaric bupivacaine 3.75 mg 2.5 mg/ml (study group). After subarachnoid injection, sensory level and motor blockade degree were registered, as were blood pressure, and heart rate at basal time and at 2, 5, 10, 15, 20 and 30 min after injection. The doses of vasopressor needed were registered as well. Surgical conditions and the duration of the surgical procedure—whether rescue analgesia or anaesthesia was needed—and sensory level regression to T12, were registered as well.ResultsSixty four patients was the calculated sample size. The study was stopped in an interim analysis because an elevated number of patients in the B0.25 group needed iv rescue anaesthesia. In the analyzed cases, blood pressure was significantly lower in the B0.5 group at the 15 and 30 min measurements. Vasopressor drugs needs were similar between groups [ephedrine accumulated mean (SD) doses 11.4 (5.2) mg vs. 9.1 (2.7) mg, p = 0.045)]. Sensory block regression to T12 was faster in the B0.25 group, [(mean (SD) 68.2 (29.0) min vs. 112.8 (17.3) min in the B0.5 group, p < 0.05]. Five out of 19 patients in the B0.25 group needed intravenous anaesthesia rescue before surgery started.ConclusionLowering hypobaric bupivacaine dose to 3.75 mg in subarachnoid anaesthesia for hip fracture repair surgery in elderly patients decrease intraoperative blood pressure, but in an important number of patients intravenous anaesthesia rescue was needed and preclude recommendation.     

A comparison of the myocardial metabolic and haemodynamic changes produced by propofol-sufentanil and enflurane-sufentanil anaesthesia for patients having coronary artery bypass graft surgery

The purpose of this study was to compare propofol-sufentanil with enflurane-sufentanil anaesthesia for patients undergoing elective coronary artery bypass graft (CABG) surgery with respect to changes in (1) haemodynamic variables; (2) myocardial blood flow and metabolism; (3) serum cortisol, triglyceride, lipoprotein concentrations and liver function; and (4) recovery characteristics. Forty-seven patients with preserved ventricular function (ejection fraction greater than 40%, left ventricular end diastolic pressure less than or equal to 16 mmHg) were studied. Patients in Group A (n = 24) received sufentanil 0.2 microgram.kg-1 and propofol 1-2 mg.kg-1 for induction of anaesthesia which was maintained with a variable rate propofol (50-200 micrograms.kg-1.min-1) infusion and supplemental sufentanil (maximum total 5 micrograms.kg-1). Patients in Group B (n = 23) received sufentanil 5 micrograms.kg-1 for induction of anaesthesia which was maintained with enflurane and supplemental sufentanil (maximum total 7 micrograms.kg-1). Haemodynamic and myocardial metabolic profiles were determined at the awake-sedated, post-induction, post-intubation, first skin incision, post-sternotomy, and pre-cardiopulmonary bypass intervals. Induction of anaesthesia produced a larger reduction in systolic blood pressure in Group A (156 +/- 22 to 104 +/- 20 mmHg vs 152 +/- 26 to 124 +/- 24 mmHg; P less than 0.05). No statistical differences were detected at any other time or in any other variable including myocardial lactate production (n = 13 events in each group), time to tracheal extubation and time to discharge from the ICU. We concluded that, apart from hypotension on induction of anaesthesia, propofol-sufentanil anaesthesia produced anaesthetic conditions equivalent to enflurane-sufentanil anaesthesia for CABG surgery.     

The effect of intravenous ondansetron on maternal haemodynamics during elective caesarean delivery under spinal anaesthesia: a double-blind,randomised, placebo-controlled trial

BackgroundSpinal anaesthesia for caesarean delivery is frequently associated with adverse effects such as maternal hypotension and bradycardia. Prophylactic administration of ondansetron has been reported to provide a protective effect. We studied the effect of different doses of ondansetron in obstetric patients.MethodsThis prospective double-blind, randomised, placebo-controlled study included 128 healthy pregnant women scheduled for elective caesarean delivery under spinal anaesthesia. Women were randomly allocated into four groups (n = 32) to receive either placebo or ondansetron 2, 4 or 8 mg intravenously before induction of spinal anaesthesia. Demographic, obstetric, intraoperative timing and anaesthetic variables were assessed at 16 time points. Anaesthetic variables assessed included blood pressure, heart rate, oxygen saturation, nausea, vomiting, electrocardiographic changes, skin flushing, discomfort or pruritus and vasopressor requirements.ResultsThere were no differences in the number of patients with hypotension in the placebo (43.8%) and ondansetron 2 mg (53.1%), 4 mg (56.3%) and 8 mg (53.1%) groups (P = 0.77), nor the percentage of time points with systolic hypotension (7.3% in the placebo group and 11.1%, 15.7% and 12.6% in the ondansetron 2, 4 and 8 mg groups, respectively, P = 0.32). There were no differences between groups in ephedrine (P = 0.11) or phenylephrine (P = 0.89) requirements and the number of patients with adverse effects.ConclusionsIn our study, prophylactic ondansetron had little effect on the incidence of hypotension in healthy parturients undergoing spinal anaesthesia with bupivacaine and fentanyl for elective caesarean delivery.     

Acute normovolaemic haemodilution vs controlled hypotension for reducing the use of allogeneic blood in patients undergoing radical prostatectomy

Blood loss in patients undergoing radical prostatectomy may be substantial. In a randomized, prospective study, we assessed two methods of reducing the need for allogeneic blood transfusion with regard to efficacy and costs. Sixty patients undergoing retropubic radical prostatectomy were allocated randomly to one of three groups. In group 1 (n = 20), acute normovolaemic haemodilution (ANH) was initiated after induction of anaesthesia; autologous blood 15 ml kg-1 was withdrawn and replaced by colloid solutions (gelatin) to maintain haemodynamic stability. In group 2 (n = 20), controlled hypotension was established using sodium nitroprusside (target mean arterial pressure (MAP) approximately 50 mm Hg). Group 3 (n = 20), without manipulations, served as a control group. Troponin T (TnT), a sensitive marker for myocardial ischaemia, and various coagulation variables were measured in the perioperative period. Packed red blood cells (PRBC) were given when haemoglobin concentration was less than 7 g dl-1. Cost calculations did not include hospital overhead costs or staff costs. In the ANH group, mean 1278 (SD 150) ml of autologous blood were withdrawn. Significantly more volume was infused in the ANH patients (gelatin 2450 (550) ml) than in the two other groups. Coagulation data (platelet count, activated partial thromboplastin time (aPTT), fibrinogen, antithrombin III (AT III), D-dimers) did not differ significantly between the three groups. The hypotension group had significantly lower blood loss (1260 (570) ml), whereas the ANH (1820 (680) ml) and control group (1920 (590) ml) did not differ significantly. Patients in the hypotension group needed significantly less PRBC (total 14 units; 75% of patients did not need PRBC) than the ANH (total 21 units; 55% of patients did not need PRBC) or control patients (total 28 units; 40% of patients did not need PRBC). Total costs were lowest in the hypotension group (41% less than in the control patients) (P < 0.05). We conclude that the use of hypotension during radical prostatectomy resulted in approximately 40% reduction in total transfusion costs. ANH was less effective and more costly than controlled hypotension.      

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.     

The effect of pre-induction glycopyrronium on the haemodynamic response of elderly patients to anaesthesia with propofol

This study investigated whether pretreatment with glycopyrronium can attenuate the hypotension caused by anaesthesia of the elderly with propofol. Twenty elderly patients (77.1 +/- 2.44 years, mean +/- SEM) of ASA physical status 2 or 3 scheduled for elective urological procedures were given glycopyrronium 0 (n = 10) or 5 micrograms.kg-1 (n = 10) in a randomised, double-blind manner, 5 min before induction of anaesthesia with propofol infused at 600 ml.h-1 (average induction dose 1.7 +/- 0.06 mg.kg-1, mean +/- SEM) followed by maintenance with a propofol infusion at 10 mg.kg-1.h-1. Although glycopyrronium significantly increased heart rate (p less than 0.01, ANOVA), the decrease in blood pressure 2 and 5 min after induction was similar in both groups. The study had a power of 80% to detect a 20 mmHg difference in systolic arterial pressure between treatment groups with p less than 0.05.     

Comparison of the effects of two intrathecal anaesthetic techniques for transurethral prostatectomy on haemodynamic and pulmonary function

BACKGROUND AND OBJECTIVE: Transurethral prostatectomy is routinely performed under spinal anaesthesia. This technique can cause hypotension, which is particularly undesirable in the elderly. The objective was to compare spinal anaesthesia for transurethral prostatectomy using hyperbaric bupivacaine 15 mg (control group) and hyperbaric bupivacaine 10 mg (limiting spread by maintaining the upright position for 15 min) and fentanyl 25 microg (fentanyl group) in terms of haemodynamic and pulmonary function. METHODS: Thirty ASA I-III patients were randomly selected and underwent spinal anaesthesia with either hyperbaric bupivacaine 15 mg (immediately positioned supine) or hyperbaric bupivacaine 10 mg (upright for 15 min) and fentanyl 25 microg. RESULTS: The greatest changes in mean arterial pressure (P = 0.9), ephedrine requirements (P = 0.8) and mean maximum change in forced vital capacity (P = 0.5) were similar in both groups. CONCLUSIONS: The addition of fentanyl 25 microg to bupivacaine 10 mg and limiting the spread of the block does not improve either haemodynamic or pulmonary function compared with bupivacaine 15 mg in patients undergoing transurethral prostatectomy.     

Failure to influence hypotension during spinal anaesthesia with a limb tourniquet

Fourty patients undergoing total hip replacement under spinal anaesthesia were allocated randomly to have a thigh tourniquet inflated after exanguination of the leg not being operated on or to act as controls. Significant hypotension (systolic arterial pressure < 70 mm Hg) was treated with i.v. ephedrine in 6 mg boluses. There was no significant difference between the two groups with respect to systolic blood pressure or requirement of ephedrine, during the hour that the tourniquet was applied or the period immediately after the removal of the tourniquet.     

Comparison of coagulation and blood loss during anaesthesia with inhaled isoflurane or intravenous propofol

Propofol has been reported to affect blood coagulation. Thisprospective, randomized study compared coagulation and bloodloss during anaesthetic maintenance with target-controlled intravenouspropofol infusion vs. inhaled isoflurane. Thirty-eight ASA I–IIIpatients undergoing head and neck surgery were allocated randomlyto receive either inhaled isoflurane at end-tidal concentration1–1.5% (group I, n=20) or target-controlled infusion (TCI)of propofol at target concentration 2–5 µg ml^–1(group P, n=18). Thrombelastography® on recalcified wholeblood was performed pre-induction, and at 15, 30, 60, 90, 120min post-induction and 30 min after anaesthesia in both groups.Blood loss was estimated from weighing swabs and the volumein suction bottles. Induced hypotension was not used, and perioperativebody temperature was similar between groups. There were no significantdifferences in thrombelastographic coagulation (R-time, K-time,maximum amplitude and angle) or fibrinolytic variables (lysisindex at 30 and 60 min) at all times between groups. Total bloodloss was also not significantly different (median group I: 350ml, range 20–1200 ml; group P: 200 ml, range 50–800ml). Shortening of R-time and widening of angle developed overtime in both groups (P<0.05 groups I and P, repeated measuresANOVA). We conclude that maintenance of anaesthesia with propofolTCI at 2–5 µg ml^–1 does not cause detectablecoagulation changes on thrombelastography® nor increasesurgical blood loss when compared to inhaled isoflurane. Br J Anaesth 2001; 86: 94–8