[Show abstract][Hide abstract] ABSTRACT: As the number of ambulatory surgery procedures continues to grow in an aging global society, the implementation of evidence-based perioperative care programs for the elderly will assume increased importance. Given the recent advances in anesthesia, surgery, and monitoring technology, the ambulatory setting offers potential advantages for elderly patients undergoing elective surgery. In this review article we summarize the physiologic and pharmacologic effects of aging and their influence on anesthetic drugs, the important considerations in the preoperative evaluation of elderly outpatients with coexisting diseases, the advantages and disadvantages of different anesthetic techniques on a procedural-specific basis, and offer recommendations regarding the management of common postoperative side effects (including delirium and cognitive dysfunction, fatigue, dizziness, pain, and gastrointestinal dysfunction) after ambulatory surgery. We conclude with a discussion of future challenges related to the growth of ambulatory surgery practice in this segment of our surgical population. When information specifically for the elderly population was not available in the peer-reviewed literature, we drew from relevant information in other ambulatory surgery populations.
Anesthesia and analgesia 03/2012; 114(6):1190-215. DOI:10.1213/ANE.0b013e31824f19b8 · 3.42 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim was to compare patients' and endoscopists' satisfaction in terms of efficacy and safety of remifentanil patient-controlled analgesia (PCA) during colonoscopy with that of a combination of midazolam and meperidine.
Sixty patients undergoing colonoscopy were randomly assigned to two groups. All of the patients received midazolam 0.03 mg/kg intravenously for premedication. In the remifentanil group, a bolus dose of remifentanil was given, and a patient-controlled sedation analgesia (PCSA) pump was set to inject further bolus doses with no "lockout" time. Patients in the meperidine group received a bolus of meperidine and sham PCSA. Non-invasive arterial blood pressure, electrocardiography, and pulse oximetry were monitored throughout the study. The Observer's Assessment of Alertness and Sedation Scale (OAA/S) was performed at baseline, every 5 min during, and after colonoscopy. Assessment of pain and satisfaction with sedoanalgesia was scheduled after colonoscopy and 24-72 h later by a 100 mm visual analog scale (VAS). The technical difficulty of the examination and the gastroenterologist's satisfaction were assessed similarly.
The degree of pain, the level of satisfaction with sedoanalgesia by patients and gastroenterologists, and the degree of difficulty experienced by the endoscopist were not different in the two groups. The time to reach an Aldrete score > or = 9 was significantly shorter in the remifentanil group (P < 0.0001); discharge times did not differ between the groups (P = 0.36). There was no difference between the groups regarding the duration of colonoscopy (P = 0.82) and the stability of vital signs. At the end of the procedure, OAA/S was significantly higher in the remifentanil group (P = 0.03).
Remifentanil PCA is safe and effective to induce sedoanalgesia during colonoscopy. Further studies should address the optimization of dosing and lock out setting.
The American Journal of Gastroenterology 03/2009; 104(5):1119-24. DOI:10.1038/ajg.2009.53 · 9.21 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To report data about "real-life" treatments with non-invasive ventilation for acute respiratory failure (ARF), managed outside intensive care units by anaesthesiologists acting as a medical emergency team.
Observational study; prospectively collected data over a 6-month period in a single centre.
Non-intensive wards in a University Hospital with 1,100 beds.
Consecutive patients with ARF for whom a ventilatory support was indicated but tracheal intubation was not appropriated or immediately needed.
Patient's characteristics, safety data, short-term outcome and organizational aspects of 129 consecutive treatments were collected. The overall success rate was 77.5%, while 10.1% were intubated and 12.4% died (all of them were "do not attempt resuscitation" patients). The incidence of treatment failure varied greatly among different diseases. Complications were limited to nasal decubitus (5%), failure to accomplish the prescribed ventilatory program (12%), malfunction of the ventilator (2%) and excessive air leaks from face mask (2%) with no consequences for patients. Three patients became intolerant to NIV. The work-load for the MET was high but sustainable: on average NIV was applied to a new case every 34 h and more than three patients were simultaneously treated.
Under the supervision of a MET, in our institution NIV could be applied in a wide variety of settings, outside the ICU, with a high success rate and with few complications.
Intensive Care Medicine 12/2008; 35(2):339-43. DOI:10.1007/s00134-008-1350-y · 7.21 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This article reports two cases of dilatative percutaneous tracheostomy performed on patients treated with double antiplatelet therapy. Both patients had cardiac arrest following myocardial infarction. After primary angioplasty with stent placement, a double antiplatelet therapy was started. Due to poor neurological outcome, dilatative percutaneous tracheostomy was performed on both patients. Antiplatelet therapy was not discontinued because of the unacceptable risk of stent thrombosis. No immediate or late hemorrhagic complications occurred. In our experience, dilatative percutaneous tracheostomy during double antiplatelet therapy can be safely performed in selected patients without other risk factors.
[Show abstract][Hide abstract] ABSTRACT: The aim of this prospective, randomized, double-blind study was to determine the effect of nitrous oxide on the desflurane requirement for blunting sympathetic response following surgical incision (MACBAR) when desflurane was combined with two different target-controlled concentrations of remifentanil (1 and 3 ng/mL).
A total of 103 patients, aged 20-50 years, ASA physical status I, scheduled to undergo general anesthesia for elective abdominal surgery, were randomly allocated to receive anesthesia with desflurane alone (Group A, n = 53), or with the addition of 60% nitrous oxide (Group N, n = 50). Patients of both groups were further assigned to receive a target-controlled plasma concentration of 1 ng/mL (Group A1, n = 27; Group N1, n = 26) or 3 ng/mL remifentanil (Group A3, n = 26, Group N3, n = 24). Sympathetic responses to surgical incision were determined after a 20 min period of constant end-tidal desflurane and target-controlled remifentanil concentrations. Predetermined end-tidal desflurane concentrations and the MACBAR for each group were determined using an up-and-down sequential allocation technique.
A total of 98 patients completed the study. The MACBAR of desflurane was 5.2% (95% confidence interval [CI95: 4.9-5.5%]) in Group A1 and 2.7% (CI95: 2.6-2.8%) in Group N1 (P<0.001), while in Groups A3 and N3 the MACBAR of desflurane was 2.2% (CI95:2-2.4%) and 2% (CI95:1.9-2.2%), respectively (P<0.01). When considering a minimum anesthetic concentration (MAC) value with a contribution of 60% nitrous oxide (0.55 MAC) in this population, the combined MACBAR values (expressed as multiples of the MAC) were 1.9 MAC for group A1, 1 MAC for group N1, 0.8 MAC for group A3, and 0.7 MAC for group N3.
The addition of 60% nitrous oxide reduces the MACBAR of desflurane by 52% when using a remifentanil concentration of 1 ng/mL, and reduces the MACBAR by 10% when using a remifentanil concentration of 3 ng/mL.
[Show abstract][Hide abstract] ABSTRACT: Ischaemic preconditioning, a response to brief sublethal episodes of ischaemia leading to a pronounced protection against subsequent lethal ischaemia, is mimicked by some pharmacological agents. Halogenated anaesthetics alone exhibit cardioprotective properties at therapeutic doses, independent of their anaesthetic and haemodynamic effect, leading to the concept of anaesthetic preconditioning. Only recently has research turned to clinical application of preconditioning protocols, and anaesthetic preconditioning has indeed been demonstrated in randomised clinical trials conducted in patients undergoing cardiac surgery - mostly coronary artery bypass graft. Most of these trials demonstrate cardiac protection by assessing postprocedural release of cardiac troponin or early postoperative cardiac function. Few studies focus on clinical outcomes, and none demonstrates an advantage in terms of mortality or cardiac morbidity. A recent meta-analysis, pooling data regarding the use of desflurane and sevoflurane, found significant reductions of in-hospital mortality, myocardial infarction rate, intensive care unit and hospital stay, time on mechanical ventilation and incidence of long term cardiac events. In conclusion, the use of desflurane and sevoflurane appears to yield a better outcome, in terms of mortality and cardiac morbidity, in patients undergoing cardiac surgery. A definitive demonstration of this concept represents a difficult task because of the low mortality rate in modern cardiac surgery and because of the number of interfering factors. Whether these cardioprotective properties also exist in non-coronary surgery settings is still controversial owing to the scarce available data.
Current Vascular Pharmacology 05/2008; 6(2):108-11. DOI:10.2174/157016108783955284 · 2.91 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this prospective, randomized study was to compare the standard regimen of midazolam and pethidine administered by the gastroenterologist versus patient controlled sedation with a propofol-fentanyl mixture during upper gastrointestinal tract endoscopic ultrasonography. Our primary end-points were patient satisfaction and patient cooperation assessed by endoscopist.
Fifty-four consecutive patients, undergoing endoscopic ultrasonography, received sedation with midazolam and pethidine (Group M: n=27) or propofol and fentanyl (Group P: n=27). Group M: pethidine 0.7mg/kg midazolam 0.04mg/kg before examination; boluses of same drugs if the sedation was insufficient plus a sham patient controlled sedation analgesia; Group P: propofol 17mg plus fentanyl 15microg before examination and a patient controlled sedation analgesia pump containing 170mg propofol plus 150microg fentanyl injecting 0.5ml every time the patient pressed the button (no "lock out"). Boluses of 1ml of the same mixture if the sedation was insufficient.
Group M: mean dosage of pethidine and midazolam 88.6 and 5mg, respectively. Group P: mean dosage of propofol and fentanyl 119.7mg and 106microg, respectively. Both groups were similar for duration and difficulty of the procedure, the grade of sedation (Observer's Assessment of Alertness/Sedation Score) and judgement by endoscopist and patient about cooperation and satisfaction. The only difference between groups was about the extra boluses administered during the procedure.
This study demonstrated that a patient controlled sedation analgesia with propofol and fentanyl is an effective and safe technique for upper gastrointestinal tract endoscopic ultrasonography procedures and results in a high level of satisfaction both for patients and operator.
[Show abstract][Hide abstract] ABSTRACT: The authors performed a meta-analysis to investigate whether the cardioprotective effects of volatile anesthetics translate into decreased morbidity and mortality in patients undergoing cardiac surgery.
It is commonly believed that the choice of the primary anesthetic agent does not result in different outcomes after cardiac surgery. Recent evidence, however, has indicated that volatile anesthetics improve postischemic recovery at a cellular level, in isolated hearts, in animals, and in humans.
Four investigators independently searched BioMedCentral and PubMed. Inclusion criteria were random allocation to treatment and comparison of a total intravenous anesthesia regimen versus an anesthesia plan including desflurane or sevoflurane performed on cardiosurgical patients. Exclusion criteria were duplicate publications, nonhuman experimental studies, and no outcome data. The endpoints were the rate of perioperative myocardial infarction and hospital mortality.
The search yielded 22 studies, involving 1,922 patients. Volatile anesthetics were associated with significant reductions of myocardial infarctions (24/979 [2.4%] in the volatile anesthetics group v 45/874 [5.1%] in the control arm, odds ratio [OR] = 0.51 [0.32-0.84], p for effect = 0.008, and p for heterogeneity = 0.77) and mortality (4/977 [0.4%] v 14/872 [1.6%], OR = 0.31 [0.12-0.80], p for effect = 0.02, and p for heterogeneity = 0.88).
Desflurane and sevoflurane have cardioprotective effects that result in decreased morbidity and mortality. The present data show for the first time that the choice of an anesthetic regimen based on administration of halogenated anesthetics is associated with a better outcome after cardiac surgery.
Journal of Cardiothoracic and Vascular Anesthesia 09/2007; 21(4):502-11. DOI:10.1053/j.jvca.2007.02.013 · 1.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: It has been speculated that midazolam may be effective in reducing the required dose of propofol during sedation.
To evaluate the sparing effect of midazolam during target-controlled propofol infusion.
Two hundred-seventy patients undergoing upper endoscopic ultrasound were randomised to receive sedation with propofol plus placebo (group A) or plus midazolam (group B). Outcome parameters were the procedure duration, the discharge time and the satisfaction of patients, operator and nurse about the quality of sedation.
The mean propofol dose administered was 364+/-207 mg in group A and 394+/-204 mg in group B. Mean procedure duration (group A: 32+/-17 min, group B: 35+/-22 min) and discharge time (group A: 39+/-30 min, group B: 38+/-24 min) were similar in both groups. No severe complications were observed. The quality of sedation was judged satisfactory for all patients by both the endoscopist and the nurse assistant without any difference between the two groups. No patient remembered the procedure or reported it as unpleasant.
Target-controlled propofol infusion provides safe and effective sedation; premedication with low dose of midazolam does not reduce the total amount of propofol administered. Further studies are needed to compare propofol alone with propofol co-administered with opioid.
[Show abstract][Hide abstract] ABSTRACT: The aim of this prospective, observational study was to evaluate changes in regional cerebral oxygen saturation (rSO2) and incidence of intraoperative cerebral desaturation in a cohort of elderly patients undergoing major abdominal surgery.
rSO2 was continuously monitored on the left and right sides of the forehead in 60 patients older than 65 yr (35 males and 25 females; ASA II-III; age: 72 +/- 5 yr; without pre-existing cerebral pathology, and baseline Mini Mental State Examination (MMSE) score >23) undergoing sevoflurane anaesthesia for major abdominal, non-vascular surgery >2 h.
Baseline rSO2 was 63 +/- 8%; cerebral desaturation (rSO2 decrease <75% of baseline or <80% in case of baseline rSO2 <50%) occurred in 16 patients (26%). The MMSE decreased from 28 +/- 1 before surgery to 27 +/- 2 on 7th postoperative day (P = 0.05). A decline in cognitive function (decrease in MMSE score > or = 2 points one week after surgery as compared to baseline value) was observed in six patients without intraoperative cerebral desaturation (13.6%) and six patients who had intraoperative cerebral desaturation (40%) (P = 0.057) (odds ratio: 4.22; CI95%: 1.1-16). Median (range) hospital stay was 14 (5-41) days in patients with an area under the curve of rSO2 <50% (AUCrSO2<50%) >10 min%, and 10 (4-30) days in those with an AUCrSO2<50% <10 min% (P = 0.0005).
In a population of healthy elderly patients, undergoing non-vascular abdominal surgery cerebral desaturation can occur in up to one in every four patients, and the occurrence of cerebral desaturation is associated with a higher incidence of early postoperative cognitive decline and longer hospital stay.
European Journal of Anaesthesiology 02/2007; 24(1):59-65. DOI:10.1017/S0265021506001025 · 3.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this prospective, randomized, double-blind study was to determine the effects of adding two different target-controlled concentrations of remifentanil (1 and 3 ng mL(-1)) on the desflurane requirement for blunting sympathetic responses after surgical incision (minimum anaesthetic concentration (MAC(BAR)).
67 patients, aged 20-50 yr, ASA I, undergoing general anaesthesia for elective abdominal surgery were enrolled and randomly allocated to receive no remifentanil infusion (n = 21) or a target-controlled effect-site concentration of 1 ng mL(-1) (n = 24) or 3 ng mL(-1) remifentanil (n = 22). All patients were anaesthetized with propofol, cisatracurium and desflurane with a mixture of 60% nitrous oxide in oxygen. Sympathetic responses to surgical incision were determined after a 20-min period of stable end-tidal desflurane and target-controlled remifentanil concentrations. Predetermined end-tidal desflurane concentrations and the MAC(BAR) for each group were determined using an up-and-down sequential-allocation technique.
The MAC(BAR) of desflurane was higher in the group receiving no remifentanil (6.25% [95% confidence interval: 5.9-6.5%]) as compared with patients of the groups receiving 1 ng mL(-1) (2.7% [2.6-2.8%]; P < 0.001) and 3 ng mL(-1) remifentanil (2% [1.9-2.2%]; P < 0.01). When considering a MAC value in this age population and the contribution of 60% nitrous oxide (0.55 MAC), the combined MAC(BAR) values, expressed as multiples of the MAC, were 1.9, 0.8 and 0.6 MAC, in the three groups, respectively.
A target-controlled concentration of 1 ng mL(-1) remifentanil results in a 57% decrease in the MAC(BAR) of desflurane combined with 60% nitrous oxide. Increasing the target concentration of remifentanil to 3 ng mL(-1) produces a further 26% decrease in the MAC(BAR) values of desflurane.
European Journal of Anaesthesiology 06/2006; 23(6):510-6. DOI:10.1017/S0265021506000305 · 3.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We sought to determine the effect-site concentration of remifentanil blunting sympathetic responses to tracheal intubation and skin incision during bispectral index (BIS)-guided propofol anesthesia. Forty-one ASA physical status I-II patients, aged 20-65 yr and undergoing major abdominal surgery, were randomly assigned to one of two groups: tracheal intubation (group TI, n = 20) or skin incision (group SI, n = 21). All patients received a target-controlled infusion of propofol of 4 microg/mL, which was then adjusted to maintain a BIS value ranging between 40 and 50. The effect-site concentration of remifentanil blocking the sympathetic responses to tracheal intubation and skin incision in 50% of cases (Ce50) was determined using an up-and-down sequential allocation method. The mean (95% confidence interval [CI]) Ce50 of remifentanil was 5.0 ng/mL for TI (95% CI, 4.7-5.4 ng/mL) and 2.1 ng/mL for SI (95% CI, 1.4-2.8 ng/mL). This study shows that effect-site concentrations of remifentanil of 5 ng/mL and 2 ng/mL are effective in blunting sympathetic responses to tracheal intubation and skin incision in 50% of patients when combined with a BIS-guided target controlled infusion of propofol.
[Show abstract][Hide abstract] ABSTRACT: The aim of this prospective, randomized, double-blind study was to determine the effects of adding nitrous oxide on sevoflurane requirement for blunting sympathetic responses after surgical incision combined with two different target-controlled concentrations of remifentanil (1 and 3 ng mL(-1)) in female.
102 female patients, aged 20-50 yr, ASA I, undergoing general anaesthesia for elective abdominal surgery were enrolled and randomly allocated to receive sevoflurane anaesthesia alone (Group A, n=53), or with the addition of 60% nitrous oxide (Group N, n=49). Patients of both groups were further assigned to receive a target-controlled remifentanil infusion with an effect-site concentration of either 1 ng mL(-1) (Group N1, n=27; Group A1, n=30), or 3 ng mL(-1) (Group N3, n=22; Group A3, n=23). Sympathetic responses to surgical incision were determined after a 20-min period of stable end-tidal sevoflurane and target-controlled remifentanil concentrations. Predetermined end-tidal sevoflurane concentrations and minimum alveolar concentration (MAC) for each group were determined using an up-and-down sequential allocation technique.
The MAC of sevoflurane was 3.96% (95% confidence interval, CI95: 3.69-4.23%) in Group A1 and 1.2% (CI95: 0.9-1.3%) in Group N1 (P < 0.01), while in Groups A3 and N3 the MAC of sevoflurane was 0.36% (CI95: 0.24-0.47%) and 0.18% (CI95: 0.1-0.3%), respectively (P < 0.05).
Adding 60% nitrous oxide reduces the MAC of sevoflurane by 70% when using a remifentanil concentration of 1 ng mL(-1) and 50% when using a remifentanil concentration of 3 ng mL(-1).
European Journal of Anaesthesiology 06/2005; 22(6):431-7. DOI:10.1017/S0265021505000736 · 3.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pregnancy exacerbates heart diseases. The aim of this clinical report is to review the different anesthesiological management of emergent cesarean section in 2 patients with heart failure. The pathophysiology of heart failure is described according to the primary cause of disease, as well as the impact of 2 different anesthetic techniques. Two case reports of a university referral hospital are presented. Both patients left the hospital in good general conditions. Case 1: a pregnant patient with severe aortic regurgitation who received epidural anesthesia. Case 2: a pregnant patient with peripartum cardiomyopathy who was given general anesthesia. Medical and surgical therapies for aortic regurgitation and peripartum dilated cardiomyopathy are evolving. Adequate knowledge of anesthesiology is required to appropriately manage these cases. We tailored the anesthetic technique to the specific characteristics of our 2 patients. The beneficial effects of sympathectomy were observed in the postoperative period of case 1; the use of high doses opiates minimised dangerous cardiovascular changes in case 2, but rapid resuscitation of the baby should be available. Selection of the anesthetic technique in obstetrics is the most challenging issue for the anesthesiologist: extensive knowledge of the pathophysiology of heart disease is required for an optimal choice.
[Show abstract][Hide abstract] ABSTRACT: A target-controlled infusion system automatically adjusts the rate of infusion of propofol to maintain a desired (target) concentration. The aim of this study was to determine whether administration of propofol with a target-controlled infusion system could improve the sedation of patients undergoing ERCP.
A total of 205 consecutive patients undergoing ERCP were sedated by using a propofol target-controlled infusion system by an anesthesiologist. The target plasma concentration of propofol ranged from 2 to 5 microg/mL. A bolus dose of fentanyl (50-100 mcg) was administered if signs of insufficient analgesia were observed at the maximum target concentration of propofol allowed. The technical difficulty of ERCP was graded on a scale from 1 (least difficult) to 5 (most difficult).
The mean dosages of propofol and fentanyl administered were 465 (245) mg and 59 (23) mcg, respectively. The total dose of propofol administered and the mean duration of ERCP were related to the degree of difficulty of the procedure. No severe complication was observed; mean time to discharge was 31 (12) minutes. Time to discharge was not influenced by the difficulty of ERCP or by the total dose of propofol administered.
A target-controlled infusion system for administration of propofol provides safe and effective sedation during ERCP. Further studies are needed to determine the cost-effectiveness and the safety profile for infusion of propofol with a target-controlled infusion system by a nonanesthesiologist during ERCP.
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to evaluate the influence of age on the outcome of liver resections. One hundred five consecutive hepatic resections were divided into two groups: > or = 65 years old [old group (O-group)] and < 65 years old [young group (Y-group)]. The two groups were first compared to evaluate the distribution of the variables potentially affecting the postoperative course, including primary diagnosis, concomitant diseases, previous upper abdominal surgery, type of operation (major or minor resection), associated procedures, presence and length of portal clamping, intraoperative blood losses and transfusions, and length of operation. The outcome of hepatic resections in the two groups was comparatively evaluated in terms of postoperative mortality, morbidity, transfusions, and length of postoperative hospitalization. The Y-group included 61 resections in 60 patients, mean age 52 +/- 10 years (mean +/- SD), range 23-64 years, whereas the O-group included 44 resections in 43 patients, mean age 71 +/- 4 years (mean +/- SD ), range 65-82 years. The O-group included more hepatocellular carcinomas (45.4% vs 18.0%, P = 0.002) and chronic liver diseases (40.9% vs 18.7%, P = 0.017); the median length of operation was slightly higher in the Y-group (300 minutes vs 270 minutes, P = 0.003). Both O-group and Y-group were comparable (P = n.s.) when evaluated for all other listed variables. As far as concerns the outcome of hepatic resections in the two groups, the length of postoperative hospitalization was identical (median 9 days, 5-60 days), whereas transfusions of packed red cells (O-group vs Y-group: 25.0% vs 16.3%, P = 0.30) or fresh frozen plasma (O-group vs Y-group: 13.6% vs 6.5%, P = 0.053) were not statistically different. Postoperative mortality included one case among young patients whereas no deaths were recorded among elderly patients. Postoperative morbidity was higher in Y-group than in O-group (31.5% vs 20.5%, P = 0.59). The age factor does not negatively affect the outcome of liver resections.
The American surgeon 06/2004; 70(5):453-60. · 0.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To evaluate the efficacy of three different concentrations of ropivacaine (0.5%, 0.75%, and 1%) together with a single concentration of hyaluronidase administered for peribulbar block.
Prospective, randomized, double-blind study.
Anesthesia department of a university teaching hospital.
68 ASA physical status I, II, and III patients undergoing elective cataract surgery.
Patients were randomly allocated to receive peribulbar block with 6.5 mL of either 0.5% (Group Ropi-5; n = 22), 0.75% (Group Ropi-7.5; n = 22), or 1% ropivacaine (Group Ropi-10; n = 24). In all patients, 0.5 mL of hyaluronidase was added to the local anesthetic solution.
A larger proportion of patients in Groups Ropi-7.5 (82%) and Ropi-10 (83%) showed complete motor block 15 minutes after injection compared with Group Ropi-5 (55%;p = 0.05, andp = 0.03, respectively). Hypotension (reduction of systolic blood pressure by 30% or more from baseline) was observed in two Group Ropi-5 patients (9%), and two Group Ropi-7.5 patients (9%;p = 0.31), whereas bradycardia (reduction in heart rate < or = 50 bpm) was observed in one Group Ropi-5 patient (4%), and three Group Ropi-10 patients (12%;p = 0.18). Seven hours after surgery, a smaller proportion of Group Ropi-10 patients (64%) showed complete recovery of sensory function as compared with both Group Ropi-5 (94%) and Group Ropi-7.5 (90%;p = 0.03 and p = 0.03, respectively). Complete recovery of motor function 1 hour after surgery was more frequent in Group Ropi-5 (37%) than in Group Ropi-7.5 (5%) or Group Ropi-10 (9%;p = 0.05 and p = 0.05, respectively); however, no other differences in recovery of motor function were observed at any other observation times, with complete recovery in all patients 7 hours after surgery.
While confirming that ropivacaine is a good option for peribulbar anesthesia, this study demonstrated that the use of 0.75% or 1% concentrations are preferred in that they produce quick and deep sensory and motor block of the operated eye. If recovery of normal motor function is important after surgery, the 0.75% concentration probably represents the best compromise.
[Show abstract][Hide abstract] ABSTRACT: The aim of this prospective, randomized, double-blind study was to determine the effects of two different target-controlled concentrations of remifentanil (1 and 3 ng/ml) on the sevoflurane requirement for blunting sympathetic responses after surgical incision (MACBAR).
Seventy-four patients aged 20-50 yr, with American Society of Anesthesiologists physical status I, were anesthetized with propofol, cisatracurium, and sevoflurane with a mixture of 60% nitrous oxide in oxygen. Then, patients were randomly allocated to receive no remifentanil infusion (n = 27) or a target-controlled plasma concentration of 1 ng/ml (n = 27) or 3 ng/ml remifentanil (n = 20). Sympathetic responses to surgical incision (presence or absence of an increase in either heart rate or mean arterial blood pressure of 15% or more above the mean of the values measured during the 2 min before skin incision) were determined after a 20-min period of stable end-tidal sevoflurane and target-controlled remifentanil concentrations. Predetermined end-tidal sevoflurane concentrations and the MACBAR for each group were determined using an up-and-down sequential-allocation technique.
The MACBAR of sevoflurane was higher in the group receiving no remifentanil (2.8% [95% confidence interval: 2.5-3.0%]) as compared with patients of the groups receiving 1 ng/ml (1.1% [0.9-1.3%]; P = 0.012) and 3 ng/ml remifentanil (0.2% [0.1-0.3%]; P = 0.006). When considering a minimum anesthetic concentration (MAC) value in this age population and the contribution of 60% nitrous oxide (0.55 MAC), the combined MACBAR values, expressed as multiples of the MAC, were 1.95 MAC, 1.1 MAC, and 0.68 MAC, in the three groups, respectively.
A target-controlled concentration of 1 ng/ml remifentanil results in a 60% decrease in the MACBAR of sevoflurane combined with 60% nitrous oxide. Increasing the target concentration of remifentanil to 3 ng/ml produces a further 30% decrease in the MACBAR values of sevoflurane.