Clinical comparison of either small doses of fentanyl or remifentanil for blunting cardiovascular changes induced by tracheal intubation

BACKGROUND

To compare in a prospective, randomized study the effects on cardiovascular changes after tracheal intubation produced by small doses of either remifentanil or fentanyl.

METHODS

With Ethical Committee approval, after intravenous midazolam premedication (0.05 mg.kg-1), 30 normotensive, ASA physical status I-II patients, without cardiovascular or respiratory diseases, and with a Mallampati score < 2, were randomly allocated to receive an intravenous bolus of either 3 micrograms.kg-1 fentanyl (n = 15) or 1 microgram.kg-1 remifentanil (n = 15) infused over 60 sec and followed by a 0.15 microgram.kg-1.min-1 continuous intravenous infusion. General anesthesia was then induced with propofol (2 mg.kg-1), followed by atracurium besilate (0.5 mg.kg-1) to facilitate tracheal intubation. Following intubation, the lungs were ventilated mechanically using a 60% nitrous oxide in oxygen mixture with a 1% inspired fraction of sevoflurane. Arterial blood pressure and heart rate were recorded before anesthesia induction (baseline), one minute after induction of anesthesia, immediately after tracheal intubation and every minute for the first five minutes after intubation.

RESULTS

Systolic arterial blood pressure values were significantly higher in the Fentanyl than in the Remifentanil group patients from 2 to 5 min after tracheal intubation (p < 0.01), while no differences were observed between the two groups in either diastolic arterial blood pressure or heart rate values. Four patients in the Remifentanil group (26%) but only one patient in the Fentanyl group (7%) showed systolic blood pressure values < 90 mmHg during the study period (p = not significant); however, the observed decreases in systolic arterial blood pressure values were transient and did not require treatment for any subject.

CONCLUSION

We conclude that in healthy normotensive patients, the control of cardiovascular responses to tracheal intubation obtained with a 1 microgram.kg-1 loading dose of remifentanil is more effective than that provided by a 3 micrograms.kg-1 bolus of fentanyl, with the advantage of no risks for postoperative respiratory depression.

Accuracy of end-tidal carbon dioxide monitoring using the NBP-75 microstream capnometer. A study in intubated ventilated and spontaneously breathing nonintubated patients

Arterial carbon dioxide partial pressure measurements using the NBP-75 microstream capnometer were compared with direct PaCO2 values in patients who were (a) not intubated and spontaneously breathing, and (b) patients receiving intermittent positive pressure ventilation of the lungs and endotracheal anaesthesia. Twenty ASA physical status I-III patients, undergoing general anaesthesia for orthopaedic or vascular surgery were included in a prospective crossover study. After a 20-min equilibration period following the induction of general anaesthesia, arterial blood was drawn from an indwelling radial catheter, while the end-tidal carbon dioxide partial pressure was measured at the angle between the tracheal tube and the ventilation circuit using a microstream capnometer (NBP-75, Nellcor Puritan Bennett, Plesanton, CA, USA) with an aspiration flow rate of 30 mL min(-1). Patients were extubated at the end of surgery and transferred to the postanaesthesia care unit, where end-tidal carbon dioxide was sampled through a nasal cannula (Nasal FilterLine, Nellcor, Plesanton, CA, USA) and measured using the same microstream capnometer. In each patient six measurements were performed, three during mechanical ventilation and three during spontaneous breathing. A good correlation between arterial and end-tidal carbon dioxide partial pressure was observed both during mechanical ventilation (r = 0.59; P = 0.0005) and spontaneous breathing (r = 0.41; P = 0.001); while no differences in the arterial to end-tidal carbon dioxide tension difference were observed when patients were intubated and mechanically ventilated (7. 3 +/- 4 mmHg; CI95: 6.3-8.4) compared to values measured during spontaneous breathing in the postanesthesia care unit, after patients had been awakened and extubated (6.5 +/- 4.8 mmHg; CI95: 5. 2-7.8) (P = 0.311). The mean difference between the arterial to end-tidal carbon dioxide tension gradient measured in intubated and non-intubated spontaneously breathing patients was 1 +/- 6 mmHg (CI95: -11-+13). We conclude that measuring the end-tidal carbon dioxide partial pressure through a nasal cannula using the NBP-75 microstream capnometer provides an estimation of arterial carbon dioxide partial pressure similar to that provided when the same patients are intubated and mechanically ventilated.

Small-dose clonidine prolongs postoperative analgesia after sciatic-femoral nerve block with 0.75% ropivacaine for foot surgery

To evaluate the effects of adding small-dose clonidine to 0.75% ropivacaine during peripheral nerve blocks, 30 ASA physical status I and II patients undergoing hallux valgus repair under combined sciatic-femoral nerve block were randomly allocated in a double-blinded fashion to receive block placement with 30 mL of either 0.75% ropivacaine alone (group Ropivacaine, n = 15) or 0.75% ropivacaine plus 1 microg/kg clonidine (group Ropivacaine-Clonidine, n = 15). Hemodynamic variables, oxygen saturation, and levels of sedation, as well as the time required to achieve surgical block and time to first analgesic request, were recorded by a blinded observer. Time to surgical blockade required 10 min in both groups. Patients in the Ropivacaine-Clonidine group were more sedated than patients in the Ropivacaine group only 10 min after block placement. No differences in oxygen saturation and hemodynamic variables, degree of pain measured at first analgesic request, and consumption of postoperative analgesics were observed between the two groups. The mean time from block placement to first request for pain medication was shorter in group Ropivacaine (13.7 h; 25th-75th percentiles: 11. 8-14.5 h) than in group Ropivacaine-Clonidine (16.8 h; 25th-75th percentiles: 13.5-17.8 h) (P = 0.038). We conclude that adding 1 microg/kg clonidine to 0.75% ropivacaine provided a 3-h delay in first request for pain medication after hallux valgus repair, with no clinically relevant side effects.

IMPLICATIONS

This prospective, randomized, double-blinded study demonstrated that, when providing combined sciatic-femoral nerve block for hallux valgus repair, the addition of 1 microg/kg clonidine to 0.75% ropivacaine prolongs the duration of postoperative analgesia by 3 h, with only a slight and short-lived increase in the degree of sedation and no hemodynamic adverse effects.

Unilateral bupivacaine spinal anesthesia for outpatient knee arthroscopy. Italian Study Group on Unilateral Spinal Anesthesia

PURPOSE

To compare unilateral and conventional bilateral bupivacaine spinal block in outpatients undergoing knee arthroscopy.

METHODS

One hundred healthy, premedicated patients randomly received conventional bilateral (n = 50) or unilateral (n = 50) spinal anesthesia with 8 mg hyperbaric bupivacaine 0.5%. A lateral decubitus position after spinal injection was maintained in unilateral group for 15 min. Times from spinal injection to readiness for surgery, block resolution, and home discharge were recorded.

RESULTS

Three patients in each group were excluded due to failed block. Readiness for surgery required 13 min (5 - 25 min) with bilateral and 16 min (15 - 30) with unilateral spinal block (P = 0.0005). Sensory and motor blocks on the operated limb were T9 (T12 - T2) with a Bromage score 0/1/2/3: 0/2/0/45 in the unilateral group and T7 (T12 - T1) with Bromage score 0/1/2/3: 4/1/6/36 with bilateral block(P = 0.026 and P = 0.016, respectively). Vasopressor was required only in five bilateral patients (P = 0.02). Two segment regression of sensory level and home discharge required 81+/-25 min and 281+/-83 min with bilateral block, and 99+/-28 min and 264+/-95 min with unilateral block (P = 0.002 and P = 0.90, respectively).

CONCLUSION

Seeking unilateral distribution of spinal anesthesia provided more profound and longer lasting block in the operated limb, less cardiovascular effects, and similar home discharge compared with bilateral spinal anesthesia, with only a slight delay in preparation time.

A prospective, randomized comparison of dexketoprofen, ketoprofen or paracetamol for postoperative analgesia after outpatient knee arthroscopy

BACKGROUND

This prospective, randomized study was conducted to evaluate the quality of postoperative pain relief when using dexketoprofen, ketoprofen, or paracetamol after outpatient knee arthroscopy.

METHODS

Without premedication, 45 ASA physical status I-II patients undergoing elective outpatient knee arthroscopy with combined sciatic-femoral nerve block, were randomly allocated to receive either 25 mg oral dexketoprofen (n = 15), 50 mg oral ketoprofen (n = 15), or 500 mg oral paracetamol (n = 15) before block placement. After completion of surgery the same pain medication was given according to standard protocols, while 50 mg oral tramadol were allowed as rescue analgesic if required by the patient. After standard discharge criteria had been fulfilled, patients were discharged from the day-surgery unit, while a telephone follow-up was performed the day after surgery using standard questionnaires evaluating the quality of pain relief during the first 24 hours after surgery. Total consumption of rescue tramadol, maximum pain complained of after hospital discharge, as well as the visual analogue scale of pain measured at hospital discharge were assessed by an independent trained observer.

RESULTS

No differences in anthropometric variables, duration of surgical procedure, and fulfillment of discharge criteria were observed between the three groups. The degree of pain measured at rest at hospital discharge was similar in the three groups, while the VAS measured during motion was higher in patients receiving paracetamol (24 +/- 2.5 mm) than in those patients treated with dexketoprofen (13 +/- 6 mm) or ketoprofen (17 +/- 5 mm) (p = 0.016). Two patients (one in ketoprofen group and one in paracetamol group) required rescue tramadol after hospital discharge; however, no differences in maximum pain complained of after surgery or patient acceptance were observed between groups.

CONCLUSIONS

This prospective, randomized study demonstrated that in outpatients receiving arthroscopic knee surgery, the use of 75 mg/day dexketoprofen was as effective and safe as 150 mg/day racemate ketoprofen, with a better pain relief during motion compared to 2 g/day paracetamol when patients were discharged from the day-surgery unit.

The effects of the single or multiple injection technique on the onset time of femoral nerve blocks with 0.75% ropivacaine

We evaluated the effect of the injection technique on the onset time and efficacy of femoral nerve block performed with 0.75% ropivacaine. A total of 30 patients undergoing arthroscopic knee surgery were randomly allocated to receive femoral nerve blockade with 0.75% ropivacaine by using either a single injection (Single group, n = 15) or multiple injection (Multiple group, n = 15). Nerve blocks were placed by using a short-beveled, Teflon-coated, stimulating needle. The stimulation frequency was set at 2 Hz, and the intensity of stimulating current, initially set at 1 mA, was gradually decreased to <0.5 mA after each muscular twitch was observed. In the Single group, 12 mL of 0.75% ropivacaine was slowly injected, as soon as the first muscular twitch was observed. In the Multiple group, the stimulating needle was inserted and redirected, eliciting each of the following muscular twitches: contraction of vastus medialis, vastus intermedius, and vastus lateralis. At each muscular twitch, 4 mL of the study solution was injected. Placing the block required 4.2 +/- 1.7 min (median, 5 min; range, 2-8 min) in the Multiple group and 3.4 +/- 2.2 min (median, 3 min; range, 1-5 min) in the Single group (P = 0.02). Onset of nerve block (complete loss of pinprick sensation in the femoral nerve distribution with concomitant inability to elevate the leg from the operating table with the hip flexed) required 10 +/- 3.7 min in the Multiple group (median, 10 min; range, 5-20 min) and 30 +/- 11 min in the Single group (median, 30 min; range, 10-50 min) (P < 0.0005). Propofol sedation was never required to complete surgery; although 0.1 mg fentanyl at trocar insertion was required in two patients of the Multiple group (13%) and nine patients of the Single group (60%) (P = 0.02). We conclude that searching for multiple muscular twitches shortened the onset time and improved the quality of femoral nerve block performed with small volumes of 0.75% ropivacaine.

IMPLICATIONS

This prospective, randomized, blinded study was conducted to evaluate the effect of searching for multiple muscular twitches when performing femoral nerve block with small volumes of 0. 75% ropivacaine. Our results demonstrated that multiple injections markedly shortened the onset time and improved the quality of nerve blockade. This technique-related effect must be carefully considered when different clinical studies evaluating the use of new local anesthetic solutions for peripheral nerve blocks are compared.

Incidence and risk factors for allogenic blood transfusion during major joint replacement using an integrated autotransfusion regimen. The Rizzoli Study Group on Orthopaedic Anaesthesia

The efficacy of an integrated autotransfusion regimen, including pre-donation and perioperative salvage of autologous blood, was prospectively evaluated in 2884 patients undergoing total hip (n = 2016) or knee arthroplasty (n = 480), and hip revision (n = 388) with either balanced general, regional, or integrated epidural/general anaesthesia. Allogenic concentrated red blood cells were transfused in the presence of symptomatic anaemia or when haemoglobin concentration was < 6 g dL-1 (10 g dL-1 in patients affected by cerebrovascular or coronary artery disease) after all salvaged and pre-donated autologous blood had been transfused. A total of 278 patients (9.6%) received allogenic blood. Risk factors for allogenic blood transfusion were: preoperative haemoglobin concentration < 10 g dL-1 (after autologous blood pre-donations) (Odds ratio: 8.7; 95% CI: 6.5-16.8; P = 0.004), hip revision versus hip or knee arthroplasty (Odds ratio: 5.8; 95% CI: 3.9-8.5; P = 0. 0001) and inability in obtaining the number of pre-donations required by the Maximum Surgery Blood Order on Schedule (Odds ratio: 3.4; 95% CI: 2.7-4.1; P = 0.0001). The incidence of perioperative complications, including wound infection and haematoma, as well as myocardial ischaemia, respiratory failure and thromboembolic complications, was higher in those patients requiring allogenic blood transfusion (29.8%) than that observed in patients receiving only autologous blood (6.6%) (P = 0.0005); while the mean time duration from surgical procedure to patient discharge from the orthopaedic ward was shorter in those patients not receiving allogenic blood transfusion (12 days; 25-75th percentiles: 8-14 days) than in those patients who required perioperative transfusion with allogenic blood (15 days; 25-75th percentiles: 10-17 days) (P = 0.0005). In conclusion, this prospective study highlighted the clinical relevance of applying an extensive and integrated autotransfusion regimen in order to reduce allogenic blood transfusion and associated complications in patients undergoing major joint replacement.

0.2% ropivacaine with or without fentanyl for patient-controlled epidural analgesia after major abdominal surgery: a double-blind study

STUDY OBJECTIVE

To evaluate the effects of adding low concentration of fentanyl to 0.2% ropivacaine when providing patient-controlled epidural analgesia (PCEA) outside the Post-Anesthesia Care Unit.

DESIGN

Prospective, randomized, double-blind study.

SETTING

Inpatients at a University Department of Anesthesia.

PATIENTS

32 ASA physical status I, II, and III patients, who were scheduled for elective major abdominal surgery, including bowel resection, hepatic resection, and pancreaticoduodenectomy.

INTERVENTIONS

Patients received standard general/epidural anesthesia. After surgery patients were randomly allocated in a double-blind fashion to receive PCEA with either 0.2% ropivacaine (n = 16) or 0.2% ropivacaine/2 microg/mL fentanyl (n = 16) [background infusion ranging between 4 and 6 mL/hr, with 1.5-mL incremental doses and a 20-min lock-out time]. Dynamic pain during coughing, sedation, pulse oxymetry, hemodynamic variables, and motor block were evaluated at 1, 6, 12, 24, and 48 hours after the end of surgery by a blinded observer. Occurrence of untoward events, including nausea, vomiting, pruritus, need for supplemental oxygen (for SpO(2) < 90%), and respiratory complications, as well as total consumption of PCEA solution and incremental doses given to the patient were also recorded.

MEASUREMENTS AND MAIN RESULTS

No differences in pain relief, motor block, degree of sedation, recovery of gastrointestinal motility, and other side effects were observed between the two groups. Patients receiving 0.2% ropivacaine alone requested far more incremental doses (23 doses [0-60] vs. 5 doses [0-25]) (p = 0.006) and needed far more analgesic solution (230 mL [140-282] vs. 204 [130-228]) (p = 0.003) than patients receiving the ropivacaine/fentanyl mixture. Peripheral oxygen saturation was lower at 12, 24, and 48 hours during ropivacaine/fentanyl infusion than in patients receiving ropivacaine alone (12 h: 91% +/- 2% vs. 95% +/- 2%, p < 0.006; 24 h: 93% +/- 1% vs. 96% +/- 2%, p = 0.003; 48 h: 92% +/- 1.8% vs. 96% +/- 1%, p = 0.004).

CONCLUSIONS

A thoracic epidural infusion of 0.2% ropivacaine, with or without fentanyl, provided effective pain relief in most patients with a very low degree of motor blockade. Adding 2 microg/ml fentanyl to 0.2% ropivacaine reduced total consumption of local anesthetic solution and need for incremental doses, but did not provide clinically relevant advantages in quality of pain relief and incidence of motor block, leading to a significant decrease in peripheral SpO(2), lasting up to 48 hours after surgery.

Combined sciatic-femoral nerve block with 0.75% ropivacaine: effects of adding a systemically inactive dose of fentanyl

To evaluate the effects of adding low-dose fentanyl to 0.75% ropivacaine during peripheral nerve blocks, 30 ASA physical status I-II patients undergoing hallux valgus repair under combined sciatic-femoral nerve block were randomly allocated in a double-blind fashion to receive nerve block placement with 30 mL of either 0.75% ropivacaine alone (group: ropivacaine, n = 15) or 0.75% ropivacaine plus fentanyl 1 microg kg(-1) (group: ropivacaine-fentanyl, n = 15). A blinded observer recorded haemodynamic variables and sedation, as well as the time required to achieve surgical block and the first request for analgesia. Readiness to surgery required 10 min (5-20 min) with 0.75% ropivacaine and 10 min (3-20 min) with the ropivacaine-fentanyl mixture. No differences in the degree of sedation, peripheral oxygen saturation, and haemodynamic variables were observed between the two groups. The degree of pain measured at first analgesic request, and the consumption of postoperative analgesics, was similar in the two groups, while the mean time from block placement to the first request for pain medication was 13.7 h (25-75th percentiles: 11.8-14.5 h) in the ropivacaine group and 13.9 h (25-75th percentiles: 10.5-14.5 h) in the ropivacaine-fentanyl group (P = not significant). We conclude that adding fentanyl 1 microg kg(-1) to 0.75% ropivacaine did not provide clinically relevant advantages in terms of onset time, quality and duration of combined sciatic-femoral nerve block in patients undergoing elective hallux valgus repair.

Regional anaesthesia for outpatient knee arthroscopy: a randomized clinical comparison of two different anaesthetic techniques

BACKGROUND

The purpose of this prospective, randomized study was to evaluate the time required to perform anaesthesia, achieve surgical block and fulfil standardized discharge criteria in outpatients receiving knee arthroscopy with either spinal anaesthesia or combined sciatic-femoral nerve block.

METHODS

After a standard midazolam/ketoprofen premedication and baseline measurement of cardiovascular parameters, 50 ASA I-II patients scheduled for elective outpatient knee arthroscopy were randomized to receive spinal anaesthesia with 8 mg of 0.5% hyperbaric bupivacaine (group Spinal, n=25), or combined sciatic-femoral nerve block with 25 ml of mepivacaine 20 mg ml(-1) and a multiple injection technique (15 ml for femoral nerve block and 10 ml for sciatic nerve block). Times lasting from skin disinfection to the end of local anaesthetic injection (preparation time) and then to achieve surgical anaesthesia (readiness for surgery), as well as times required for block resolution, micturition, unassisted ambulation, and home discharge were recorded by a blinded observer. Occurrence of adverse events was also recorded.

RESULTS

Preparation time (mean+/-SD) was longer with sciatic-femoral block (8+/-2.7 min) than spinal anaesthesia (5+/-2.1 min) (P=0.0002) while no differences were observed in the time required to achieve readiness for surgery (14+/-5 min and 15+/-6 min in the Spinal and Sciatic-femoral groups, respectively). No differences in haemodynamic side effects and need for intraoperative additional analgesia were observed. Patients receiving spinal anaesthesia showed a faster resolution of nerve block and longer time to micturition (137+/-49 min and 231+/-101 min) than patients receiving peripheral nerve blockade (206+/-51 min and 145+/-36 min) (P<0.0005 and P=0.002, respectively); however, no differences were observed in the time required to fulfil standardized discharge criteria (241+/-101 min in group Spinal and 209+/-70 min in group Sciatic-femoral; P=0.86).

CONCLUSION

In patients receiving elective outpatient knee arthroscopy, using a combined sciatic-femoral nerve block with 25 ml of mepivacaine 20 mg ml(-1) and a multiple injection technique results in a slightly longer preoperative time but provides similarly effective anaesthesia with no differences in home discharge times as compared to spinal anaesthesia with 8 mg hyperbaric bupivacaine.

[Bispectral index: clinical effectiveness and role in reducing anesthetic drug consumption]

A numeric value derived from bispectral analysis of EEG, the bispectral index (BIS), has been recently introduced as a monitor of the hypnotic component of anaesthesia. Application of BIS monitoring in anaesthesia appears extremely interesting to drugs titration and drugs economy, and in the evaluation of time for discharge in a one day surgery regimen. In this prospective study ASA I-II patients for Day-Surgery were enrolled in three groups: subaracnoid anaesthesia (SA), general anaesthesia (GA) with BIS and GA without BIS monitoring. At present 35 patients for DS operative hysteroscopy were enrolled. No significant differences were measured between the GA groups. A longer time of recovery was necessary in the SA group. A greater amount of anaesthetic in BIS group could be attributed to a better monitoring of sedation which prevents intraoperative awakening.

Effects of pneumoperitoneum and reverse Trendelenburg position on cardiopulmonary function in morbidly obese patients receiving laparoscopic gastric banding

We prospectively evaluated the effects of pneumoperitoneum and reverse Trendelenburg position on cardiopulmonary function in 20 ASA physical status II-III morbidly obese patients (body mass index > 35 kg m(-2)) undergoing laparoscopic gastric banding. After general anaesthesia was induced, patients' lungs were ventilated using intermittent positive pressure ventilation (at measurement times, the following parameters were used: tidal volume 12 mL kg(-1) ideal body weight, respiratory rate of 12 bpm, an inspiratory to expiratory time ratio of 1:2). Haemodynamic variables, blood gas parameters, and lung/chest compliance were recorded: in the supine position, after induction of general anaesthesia (T0, baseline) and induction of pneumoperitoneum (T1); after placing the patient in a 25 degree reverse Trendelenburg position (T2); during the surgical time (T3); before deflating the abdomen (T4); after pneumoperitoneum resolution (T5), and before the end of anaesthesia, with the patient supine (T6). The PaO2, PaO2/FiO2 ratio, and lung/chest compliance decreased during the study. After the pneumoperitoneum had been resolved, lung/chest compliance but not oxygenation parameters returned to baseline values. The arterial to end-tidal CO2 tension difference progressively increased from 0.38+/-0.3 kPa (2.85+/-2.25 mmHg) (T0) to 0.63+/-0.3 kPa (4.73+/-2.25 mmHg) (T6). In morbidly obese patients, undergoing laparoscopic gastric banding, a CO2 pneumoperitoneum markedly affected gas exchange and lung/chest compliance, while positioning the patient in a 25 degree reverse Trendelenburg position had no beneficial effects.

Cardiovascular homeostasis during inhalational general anesthesia: a clinical comparison between sevoflurane and isoflurane. On behalf of the Italian Research Group on sevoflurane

STUDY OBJECTIVE

To obtain more information on cardiovascular homeostasis and patient discharge from the recovery area after general anesthesia with either sevoflurane or isoflurane as the main anesthetic.

DESIGN

Prospective, randomized, multicenter study.

SETTING

Inpatient anesthesia at 13 University Departments of Anesthesia.

PATIENTS

247 ASA physical status I, II, and III patients, aged 18 to 85 years, receiving general anesthesia for elective urological, orthopedic, ENT, vascular, and low abdominal surgery.

INTERVENTIONS

General anesthesia was maintained using a 60% nitrous oxide in oxygen mixture with either isoflurane (n = 125) or sevoflurane (n = 122) adjusted according to hemodynamic variables.

MEASUREMENTS AND MAIN RESULTS

Occurrence of hypotension [systolic arterial blood pressure (SBP) decrease >30% from baseline], hypertension (SBP increase >30% from baseline), bradycardia [heart rate (HR) <50 bpm], or tachycardia (HR>100 bpm) provoked stepwise changes in the inspired concentration of the study drug. If this action proved to be ineffective after an adequate stabilization period, a specific treatment was given, and the need for pharmacological treatment was recorded as a hemodynamic side effect by an independent observer. No differences in duration of anesthesia were observed between sevoflurane (126 +/- 76 min) and isoflurane patients (139 +/- 60 min). Mean duration from anesthetic discontinuation to fulfillment of discharge criteria was shorter after sevoflurane (21 min; 25(th) to 75(th) percentiles: 27 to 13 min) than isoflurane (27 min; 25(th) to 75(th) percentiles: 17 to 35 min) (p < 0.0005). Hemodynamic side effects requiring therapy occurred in 18 sevoflurane patients (14.6%) and 26 isoflurane patients (20.8%) (p = NS). The risk for hemodynamic side effects increased with age (>50 vs. < or OFFyrs: odds ratio 2.5; 95% CI 1.2 to 5.4; p = 0.015) and ASA physical status (III vs. I and II: odds ratio 2.2; 95% CI 0.9 to 5.7; p = 0.048). When only patients over 50 years of age were considered (72 in the sevoflurane group and 79 in the isoflurane group), the incidence of hemodynamic side effects was higher with isoflurane (29.1%) than with sevoflurane (15.2%) (odds ratio 2.3; 95% CI 1.0 to 5.2; p = 0.04).

CONCLUSIONS

Sevoflurane provided equally safe and effective control of cardiovascular homeostasis as isoflurane, with a more rapid discharge from the recovery area. Interestingly, patients over 50 years of age showed a lower risk for hemodynamic side effects when receiving sevoflurane than isoflurane.

Unilateral spinal anesthesia or combined sciatic-femoral nerve block for day-case knee arthroscopy. A prospective, randomized comparison

BACKGROUND

To evaluate the time required to achieve surgical block and fulfill standardized discharge criteria in outpatients receiving knee arthroscopy with either unilateral spinal anesthesia or combined sciatic-femoral nerve block.

METHODS

After a standard midazolam/ketoprofen premedication and baseline measurement of cardiovascular parameters, 50 ASA physical status I-II patients scheduled for elective outpatient knee arthroscopy were randomized to receive unilateral spinal anesthesia with 8 mg of 0.5% hyperbaric bupivacaine injected without barbotage through a 25-gauge Whitacre spinal needle (group USA, n = 25), or combined sciatic-femoral nerve block with 25 ml of 2% mepivacaine (15 ml for femoral nerve block and 10 ml for sciatic nerve block) (group SFNB, n = 25). Times from local anesthetic injection to achievement of surgical block defined as the presence of adequate motor (complete motor blockade of the operated limb in the USA group and inability to move the ankle and the knee of the operated limb in the SFNB group) and sensory (loss of pinprick sensation at T12 on the operated side in the USA group, or in the femoral and sciatic nerves distribution in the SFNB group) blocks was recorded. Times to block resolution, urination, unassisted ambulation, and readiness to home discharge were also recorded by a blind observer, as well as occurrence of untoward events during surgery.

RESULTS

Surgical block was achieved in 15 +/- 6 min in group USA and 16 +/- 6 min in group SFNB (p = NS). No differences in hemodynamic undesired effects and success rate were observed. Even though USA patients showed a faster time to ambulation (166 +/- 44 min versus 217 +/- 49 min, p = 0.002) and later urination (240 +/- 90 min versus 145 +/- 36 min, p = 0.0001) than SFNB group, no differences in home discharging were reported (246 +/- 98 min versus 211 +/- 77 min, respectively). Bladder catheterization was required in 2 patients of USA group only; however, no patient was admitted to the hospital because of urinary retention.

CONCLUSIONS

In outpatient knee arthroscopy, a combined sciatic-femoral nerve block with 2% mepivacaine provides similarly successful anesthesia with onset times and home discharge similar to those provided by unilateral spinal anesthesia.

Cervical plexus anesthesia for carotid endarterectomy: comparison of ropivacaine and mepivacaine

PURPOSE

To evaluate the effectiveness of cervical plexus block performed with ropivacaine 0.75% or 1%, or mepivacaine 2%.

METHODS

In a prospective, randomized, double-blind study, 60 patients received deep cervical plexus block with 0.2 ml x kg(-1) divided among C2-C4 injections using ropivacaine 0.75% and 1% or mepivacaine 2%. A blinded observer recorded loss of pin-prick sensation every minute in the C2-C4 dermatomes until readiness for surgery. Then, a superficial cervical block was performed with 0.15 ml x kg(-1) lidocaine 1%. The need for intraoperative supplemental analgesia and degree of pain and time of first postoperative pain medication were also recorded.

RESULTS

General anesthesia was not required to complete surgery in any case. No differences in the need for intraoperative supplemental analgesia was observed (7, 6, and 9 patients with ropivacaine 0.75% and 1% or mepivacaine 2%, respectively). Readiness to surgery required 15 (10-25) min with ropivacaine 0.75%, 18 (8-20) min with ropivacaine 1%, and 15 (5-20) min with mepivacaine 2% (P = NS); while patients asked for first postoperative pain medication after 10 (4-13) hr and 9 (6.5 - 11) hr with ropivacaine 0.75% and 1% compared with 5 (0-8) hr with mepivacaine 2% (P<0.05).

CONCLUSION

Ropivacaine 0.75% or 1% are appropriate choices when performing cervical plexus anesthesia for carotid endarterectomy, providing nerve block characteristics similar to those of mepivacaine 2%, but with the advantage of longer postoperative pain relief.

Interscalene brachial plexus anesthesia with either 0.5% ropivacaine or 0.5% bupivacaine

BACKGROUND

To compare intra- and postoperative clinical properties of interscalene brachial plexus block performed with either 0.5% ropivacaine or 0.5% bupivacaine.

METHODS

EXPERIMENTAL DESIGN

prospective, randomized, double-blind study.

SETTING

in patient at the University Hospital, Department of Orthopedic Surgery.

PATIENTS

30 ASA physical status I-II patients scheduled for elective shoulder surgery.

INTERVENTIONS

interscalene brachial plexus block was performed using the multiple injection technique and a nerve stimulator by injecting 20 ml of either 0.5% ropivacaine (n = 15) or 0.5% bupivacaine (n = 15). Postoperative analgesia consisted of 100 mg intravenous ketoprofen, if required. A blind observer evaluated hemodynamic variables as well as sensory and motor blocks from the end of injection to achieve a surgical anesthesia (readiness for surgery: loss of pinprick sensation from C4 to C7 with the inability to elevate the operated limb against gravity). The time lasting from block placement to first requirement for postoperative pain medication was also recorded.

RESULTS

No differences in anthropometric parameters and hemodynamic variables were observed throughout the study, and no signs of central nervous system (CNS) and cardiovascular toxicity, or other untoward events were reported in any patients. Readiness for surgery was obtained after 28 +/- 15 min with 0.5% bupivacaine and 22 +/- 8 min after 0.5% ropivacaine (p = NS). No differences in postoperative pain relief was observed between the two groups (11.1 +/- 5 hrs after 0.5% ropivacaine and 10.9 +/- 3.9 hrs after 0.5% bupivacaine, respectively).

CONCLUSIONS

This study confirmed that 0.5% ropivacaine has clinical properties similar to those of 0.5% bupivacaine, when used for interscalene brachial plexus block, providing similarly long duration in postoperative pain relief. Compared with bupivacaine, ropivacaine has the further advantage of a lower potential for central nervous system and cardiovascular toxicity.

Patient supplemented epidural analgesia after major abdominal surgery with bupivacaine/fentanyl or ropivacaine/fentanyl

PURPOSE

To compare analgesic efficacy and occurrence of motor block and other side effects during patient supplemented epidural analgesia (PSEA) with either ropivacaine/fentanyl or bupivacaine/fentanyl mixtures.

METHODS

In a prospective, randomized, double-blind study, 32 ASAI-III patients undergoing major abdominal surgery received an epidural catheter at the T8- T10, followed by integrated general epidural anesthesia. Postoperative epidural analgesia was provided using a patient controlled pump with either ropivacaine 0.2%/2 microg x ml(-1) fentanyl (group Ropivacaine, n = 16) or bupivacaine 0.125%/2 microg x ml(-1) fentanyl (group Bupivacaine, n = 16) [background infusion 4-6 ml x hr(-1), 1.5 ml Incremental Doses and 20 min lock out]. Verbal pain rating score, number of incremental doses, consumption of epidural analgesic solution and rescue analgesics, sedation (four-point scale), and pulse oximetry were recorded by a blind observer for 48 hr after surgery.

RESULTS

No differences in pain relief, motor block, degree of sedation, pulse oximetry and other side effects were observed between the two groups. The number of incremental doses and the volume of analgesic solution infused epidurally were higher in patients receiving the bupivacaine/fentanyl mixture (10 [0-52] I.D. and 236 [204-340] ml) than in patients receiving the ropivacaine/fentanyl solution (5 [0-50] I.D. and 208 [148-260] ml) (P = 0.03 and P = 0.05, respectively).

CONCLUSION

Using a ropivacaine 0.2%/2 microg x ml(-1) fentanyl mixture for patient supplemented epidural analgesia after major abdominal surgery provided similar successful pain relief as bupivacaine 0.125%/2 microg x ml(-1) fentanyl, but patients receiving bupivacaine/fentanyl requested more supplemental.

Interscalene brachial plexus anaesthesia with 0.5%, 0.75% or 1% ropivacaine: a double-blind comparison with 2% mepivacaine

We have compared interscalene brachial plexus block performed with ropivacaine or mepivacaine in 60 healthy patients undergoing elective shoulder surgery. Patients were allocated randomly to receive interscalene brachial plexus anaesthesia with 20 ml of 0.5% ropivacaine (n = 15), 0.75% ropivacaine (n = 15), 1% ropivacaine (n = 15) or 2% mepivacaine (n = 15). Readiness for surgery (loss of pinprick sensation from C4 to C7 and inability to elevate the limb from the bed) was achieved sooner with 1% ropivacaine (mean 10 (SD 5) min) than with 0.5% ropivacaine (22 (7) min) (P < 0.001) or 2% mepivacaine (18 (9) min) (P < 0.02). Postoperative analgesia was similar with the three ropivacaine concentrations (11.5 (5) h, 10.7 (2) h and 10 (2.4) h with 0.5%, 0.75% and 1% concentrations, respectively) and nearly two-fold longer compared with 2% mepivacaine (5.1 (2.7) h) (P < 0.001).

Do we need new supraglottic devices? Clinical appraisal of the cuffed oropharyngeal airway (COPA)

BACKGROUND

The laryngeal mask airway (LMA) has been widely studied for both conventional and nonconventional uses, while the literature on the cuffed oropharyngeal airway (COPA) is still limited. The purpose of this manuscript was to review the initial appraisal of efficacy, safety, effects on hemodynamics and respiratory function, induction agents and drug requirements of this new supraglottic device.

METHODS

We reviewed main results of studies recently published on peer reviewed journals concerning the clinical uses of COPA.

RESULTS

When used in healthy adults undergoing general anesthesia for routine minor procedures, the COPA and LMA are substantially equivalent. The LMA is associated with a higher first-time placement rate and fewer manipulations during usage, but the incidence of airway untoward events during COPA anesthesia is equivalent to that reported when using an LMA. The quality of breathing and capnography during COPA ventilation is similar to that provided by the LMA ventilation, with clinically relevant decrease in the physiological deadspace/tidal volume ratio and arterial to end-tidal CO2 tension difference compared with facemask ventilation. In selected patients without risk factors for regurgitation of gastric content, positive-pressure ventilation is similarly successful and safe with the COPA as with the LMA. The COPA seems to be less stimulating than LMA because it has been demonstrated to cause a lower incidence of pharyngeal trauma and sore throat in the immediate postoperative period, requires shorter exposure to an inhalational anesthetic and lower concentrations of propofol to be successfully placed, and is associated with lower effects on the patient's hemodynamic homeostasis than LMA.

CONCLUSIONS

More extensive clinical evaluations should be advocated to better understand the risk/benefit ratio of this new supraglottic device; however, it may be concluded that in healthy adults receiving general anesthesia for short procedures the COPA allows for an effective and safe control of the patient's airway and ventilation.

A clinical comparison of ropivacaine 0.75%, ropivacaine 1% or bupivacaine 0.5% for interscalene brachial plexus anaesthesia

In order to compare interscalene brachial plexus block performed with ropivacaine or bupivacaine, 45 healthy, unpremedicated patients, undergoing elective shoulder surgery, were randomly allocated to receive interscalene brachial plexus anaesthesia with 20 mL of either ropivacaine 0.75% (n = 15), ropivacaine 1% (n = 15), or bupivacaine 0.5% (n = 15). Readiness for surgery (loss of pinprick sensation from C4 to C7 and inability to elevate the limb from the bed) was achieved later with bupivacaine 0.5% (28 +/- 15 min) than with ropivacaine 1% (10 +/- 5 min) (P = 0.005) and ropivacaine 0.75% (15 +/- 8 min) (P = 0.0005). No differences in success rate were observed between the three groups; however, seven patients receiving bupivacaine 0.5% required intra-operative analgesic supplementation (fentanyl 0.1 mg intravenous) compared with one patient receiving ropivacaine 0.75%, and two patients treated with ropivacaine 1% (P = 0.02). The time from the block placement to first request for pain medication was similar in the three groups (10.7 +/- 2 h, 11 +/- 2.4 h, and 10.9 +/- 3.9 h after 0.75% and 1% ropivacaine or 0.5% bupivacaine, respectively). We conclude that interscalene brachial plexus block performed with 20 mL of either 0.75% or 1% ropivacaine allows for a prolonged post-operative pain relief, similar to that provided by bupivacaine 0.5%, with short onset time of surgical anaesthesia.

The pressor response after laryngeal mask or cuffed oropharyngeal airway insertion

BACKGROUND

Since the cuffed oropharyngeal airway (COPA) has been suggested to cause less pharyngeal trauma than the laryngeal mask airway (LMA), we conducted a prospective, randomised study to compare haemodynamic changes after placing either the COPA or LMA in healthy anaesthetised adults.

METHODS

After standard midazolam premedication (0.05 mg kg(-1) IV), general anaesthesia (IV propofol 2 mg kg(-1)) was induced in 60 ASA physical status I-II, 18-65-yr-old patients, who were randomly allocated to receive COPA (n=30) or LMA (n= 30) placement and then mechanically ventilated using a 60% nitrous oxide and 1% isoflurane in oxygen mixture (TV=8 ml kg(-1), RR=12 b.p.m., I/E=1/2). Haemodynamic variables were recorded 20 min after the midazolam premedication (baseline), and then every 1 min until 10 min after general anaesthesia induction.

RESULTS

Nine patients of group COPA (30%) required chin lift, jaw thrust or head tilt to maintain adequate ventilation, while no problems were observed in the LMA group (P<0.0005); however, in no case did the designed extratracheal airway have to be removed due to unsuccessful mechanical ventilation, and no signs of gastric insufflation or regurgitation were reported. The maximum mean changes in haemodynamic variables were more marked after LMA placement (SAP: 12%+/-13%; DAP: 11%+/-18%; HR: 13%+/-16%) than COPA placement (SAP: -3%+/-18%; DAP: -5%+/-16%; HR: 4%+/-13%) (P<0.005, P<0.005, and P<0.01 for SAP, DAP and HR, respectively). Group LMA showed higher SAP and DAP values than group COPA only during the first 3 min after airway insertion.

CONCLUSION

In healthy, anaesthetised patients, placing a cuffed oropharyngeal airway is associated with smaller cardiovascular changes after airway insertion compared with the laryngeal mask airway.

Anaesthesia for ultrasound guided oocyte retrieval: midazolam/remifentanil versus propofol/fentanyl regimens

To evaluate the quality of intra-operative anaesthesia and recovery characteristics of two different anaesthesia regimens, 60 healthy women undergoing ultrasound guided oocyte retrieval for in vitro fertilization procedures were randomly allocated to receive either a propofol/fentanyl or a midazolam/remifentanil based anaesthesia. The surgical procedure was successful in all patients and no severe side effects were reported by any patient. Four patients in the midazolam/remifentanil group (13%) would not accept the same anaesthetic procedure for further in vitro fertilization treatment due to intra-operative awareness, while all propofol/fentanyl patients were prepared to accept the same procedure again (P < 0.05). Patients in the propofol/fentanyl group required manual ventilation more frequently through a facemask than those patients treated with the midazolam/remifentanil combination (50% and 30%, respectively; P < 0.05). The time to achieve an Aldrete's score of 10 was shorter in the midazolam/remifentanil patients (2 +/- 2 min) than in those who received propofol/fentanyl (4 +/- 2 min) (P < 0.001), but no differences were observed in the time required to be 'fit to discharge' from the post-anaesthesia care unit. We conclude that the use of a midazolam/remifentanil regimen is as effective and safe as a fentanyl/propofol regimen in patients undergoing transvaginal oocyte retrieval for in vitro fertilization procedures.

Peribulbar anesthesia with either 0.75% ropivacaine or a 2% lidocaine and 0.5% bupivacaine mixture for vitreoretinal surgery: a double-blinded study

No study has evaluated the efficacy of ropivacaine in peribulbar block for ophthalmic surgery. The purpose of this prospective, randomized, double-blinded study was to compare ropivacaine and a lidocaine-bupivacaine mixture in peribulbar anesthesia. Sixty ASA physical status I or II patients scheduled for elective vitreoretinal surgery were randomized to receive a peribulbar block with 8 mL of either 0.75% ropivacaine (ropivacaine group, n = 30) or a 1:1 mixture of 2% plain lidocaine and 0.5% plain bupivacaine (lido-bupivacaine group, n = 30). Time required for onset of surgical anesthesia, quality of postoperative analgesia, incidence of side effects, and analgesic consumption were recorded. Surgical block was achieved after 8 +/- 5 min in the lido-bupivacaine group and after 10 +/- 5 min in the ropivacaine group (P = 0.23). A 3-mL supplemental injection 15 min after block placement was required in 6 patients in the lido-bupivacaine group (20%) and in 10 patients in the ropivacaine group (33%) due to inadequate motor block (P = 0.38). On Postoperative Day 1, 26 patients in the ropivacaine group (87%) reported no pain at the verbal rating score, compared with 18 patients in the lido-bupivacaine group (60%) (P = 0.005). We conclude that 0.75% ropivacaine may be a suitable choice when performing peribulbar anesthesia for vitreoretinal surgery.

IMPLICATIONS

Quick onset of block with prolonged postoperative analgesia is an important goal in regional anesthesia for ophthalmic surgery. Evaluating clinical properties of 0.75% ropivacaine and a 1:1 mixture of 2% lidocaine and 0.5% bupivacaine for peribulbar anesthesia, we demonstrated that ropivacaine has an onset similar to that of the lidocaine-bupivacaine mixture and provides a better quality of postoperative analgesia.

Arterial to end-tidal carbon dioxide tension difference in anaesthetized adults mechanically ventilated via a laryngeal mask or a cuffed oropharyngeal airway

To evaluate arterial (PaCO2), end-tidal (PETCO2) and carbon dioxide tension difference during mechanical ventilation with extratracheal airways, 60 patients ASA physical status I-II, receiving general anaesthesia for minor extra-abdominal procedures were randomly allocated to receive either a cuffed oropharyngeal airway (group COPA, n = 30) or a laryngeal mask (group LMA, n = 30). The lungs were mechanically ventilated by IPPV using a 60% nitrous oxide and 1-1.5% isoflurane in oxygen mixture (VT = 8 mL kg-1; RR = 12 b min-1; l/E = 1/2). After PETCO2 had been stable for at least 10 min after airway placement, haemodynamic variables and PETCO2 were recorded and an arterial blood sample was obtained for measurement of PaCO2. No differences in anthropometric parameters, smoking habit, haemodynamic variables and incidence of untoward events were observed between the two groups. Airway manipulation, to maintain adequate ventilation, was required in only nine patients in the cuffed oropharyngeal airway group (30%) (P < 0.0005); however, in no case was it necessary to remove the designated extratracheal airway due to unsuccessful mechanical ventilation. The mean difference between arterial and end-tidal carbon dioxide partial pressure was 0.4 +/- 0.3 KPa in the laryngeal mask group (95% confidence intervals: 0.3-0.5 KPa) and 0.3 +/- 0.26 KPa in the cuffed oropharyngeal airway group (95% confidence intervals: 0.24-0.4 KPa) (P = NS). We conclude that in healthy adults who are mechanically ventilated via the cuffed oropharyngeal airway, the end-tidal carbon dioxide determination is as accurate an indicator of PaCO2 as that measured via the laryngeal mask, allowing capnometry to be reliably used to evaluate the adequacy of ventilation.