piperidines and Blood-Loss--Surgical

It is crucial to reduce bleeding during functional endoscopic sinus surgery (FESS). Our primary goal was to evaluate the effect of intravenous lidocaine infusion (ILI) as an adjunct to the enhanced recovery after surgery (ERAS) protocols on intraoperative bleeding during FESS. We hypothesized that ILI could improve the surgical field.. Forty-three adult patients ASA I-II, 20-50 years old, undergoing FESS under general anesthesia were randomly assigned to receive immediately after induction of anesthesia either ILI 1.5 mg/kg as a bolus followed by 1.5 mg/kg/ h until the end of surgery (Group L) or normal saline (Group NL). Intraoperative blood loss, bleeding and surgeon satisfaction scores, mean arterial pressure (MAP), heart rate (HR), extubation and eye-opening times, and time to first analgesic request were recorded.. Intraoperative bleeding and bleeding scores in the first 45 min after ILI were decreased, with better surgeon satisfaction in Group L (P<0.05). MAP and HR values were lower after ILI in Group L during surgery (P<0.05). Extubation and eye-opening times were shorter (P=0.001) and the time to first analgesic request was prolonged (P=0.001) in Group L than in Group NL.. ILI decreased intraoperative blood loss and improved the surgical field visibility in the first 45 min during FESS.

Topics: Adult; Anesthesia, General; Blood Loss, Surgical; Humans; Infusions, Intravenous; Lidocaine; Middle Aged; Piperidines; Young Adult

To compare dexmedetomidine with remifentanil in functional endoscopic sinus surgery (FESS) in regards to intra-operative bleeding, anesthetic consumption and post-operative recovery. Randomized, double blind study. Tertiary care medical center. Fifty patients with nasal polyposis who had been scheduled for FESS were randomly divided into two groups. In group D (n = 25), dexmedetomidine 1 µg/kg infused intravenous (IV) over 10 min before anesthesia induction, followed by a continuous of 0.7 µg/kg/h infusion during operation. In group R (n = 25), 1 µg/kg remifentanil IV bolus, was administered with induction of anesthesia and continued 0.25-0.50 µg/kg/min during operation. Heart rates, mean arterial pressure, end tidal CO

Topics: Adult; Blood Loss, Surgical; Dexmedetomidine; Double-Blind Method; Endoscopy; Female; Follow-Up Studies; Humans; Hypnotics and Sedatives; Hypotension, Controlled; Infusions, Intravenous; Injections, Intravenous; Male; Middle Aged; Nasal Polyps; Outcome Assessment, Health Care; Piperidines; Remifentanil

Breast reduction surgery is a common cosmetic surgery with a high incidence of blood loss and transfusion. In this surgery, the reduction of blood loss related to surgical manipulation and the volume of resected tissue is a target. In the present study, we compared the effects of esmolol-induced controlled hypotension on surgical visibility, surgical bleeding, and the duration of surgery in patients anesthetized with propofol/remifentanil (PR) or sevoflurane/remifentanil (SR).. Patients in the American Society of Anesthesiologists I/II risk group undergoing breast reduction surgery were prospectively randomized into PR (n = 25) and SR (n = 25) groups. Controlled hypotension was induced with esmolol in both groups. During the intraoperative period, the heart rate (HR), mean arterial pressure (MAP), operation duration, volume of intraoperative blood loss, volume of blood received through postoperative drains, volume of resected tissues, and surgical area bleeding score were recorded.. The duration of operation in the incisional period was shorter in group PR compared to group SR (P = 0.04). The change in HR was lower in incision and hemostasis periods in the group PR compared to the group SR (P < 0.001). Total intraoperative intraoperative bleeding volume and volume of blood received through drains on postoperative postoperative day 1, day 2, and in total were found to be significantly lower in group PR compared to group SR. Surgical visibility scoring was more effective in group PR compared to SR.. In the breast reduction surgery performed under esmolol-induced controlled hypotension, the effect of propofol + remifentanil anesthesia on the duration of incisional surgery, surgical visibility, and volume of surgical blood loss was more reliable and effective compared to that of sevoflurane + remifentanil, which seems to be an advantage.

Topics: Adrenergic beta-1 Receptor Antagonists; Adult; Anesthesia, Intravenous; Anesthetics, Inhalation; Anesthetics, Intravenous; Blood Loss, Surgical; Female; Humans; Hypotension, Controlled; Mammaplasty; Methyl Ethers; Middle Aged; Piperidines; Propanolamines; Propofol; Remifentanil; Sevoflurane

This study aims to study the impact of dexmedetomidine on the deformability of erythrocyte in patients with laparoscopic cholecystectomy. 40 patients scheduled for laparoscopic cholecystectomy were randomly divided into 2 groups: Dexmedetomidine group (0.5µg/kg loading within 10 min and 0.5μg•kg-1•h-1maintenance to the end of pneumoperitoneum, n=20, Group A) and control group (normal saline at the identical, n=20, Group B). The induction and maintenance of anesthesia of two groups were identical. Erythrocyte deformability index (EI) and haematocrit (Hct) were assayed before anesthesia and after the operation. Operation time, intraoperation blood loss and the amount of anesthetics were measured respectively. Compared with T0 (0.81±0.06), EI was significantly increased at T1 in-group B (P<0.05); Compared with T0 (0.82±0.07), EI was increased at T1 in-group A, but it showed no statistically significant difference (P>0.05). Compared with group B (1051±219) µg, (628±97) mg, the consumption of remifentanil and propofol were significantly reduced in-group A (874±167) μg, (410±77) mg (P<0.05). Dexmedetomidine can improve the deformability of erythrocyte of postoperative and reduce the amount of anesthetics.

Topics: Adrenergic alpha-2 Receptor Agonists; Adult; Anesthetics, Intravenous; Blood Loss, Surgical; China; Cholecystectomy, Laparoscopic; Dexmedetomidine; Drug Administration Schedule; Erythrocyte Deformability; Female; Hematocrit; Humans; Infusions, Intravenous; Male; Middle Aged; Operative Time; Piperidines; Propofol; Remifentanil; Time Factors; Treatment Outcome

The Le Fort I osteotomy (L-I) requires extensive dissection and manipulation of tissue, causing hemodynamic instability and an undesirable postoperative stress response. This study aimed to clarify the most effective dose of remifentanil during L-I.. This study was designed as a prospective, randomized, controlled double-blinded study. Patients (American Society of Anesthesiologists physical status I to II) undergoing L-I were randomly assigned to receive anesthesia with propofol and remifentanil under 3 remifentanil dose conditions: 0.25 μg/kg/minute (group 1), 0.5 μg/kg/minute (group 2), and 0.75 μg/kg/minute (group 3). All patients underwent L-I with propofol and remifentanil target-controlled anesthesia. The study endpoints were mean arterial pressure (MAP) and heart rate. Data were recorded before L-I (20-minute period before surgery), during L-I (from the beginning of surgery to downfracture), and after L-I (20-minute period after downfracture). Average age, gender, average body mass index, aimed maxillary position, average bispectral index, average surgery time, and average blood loss also were examined. Data were analyzed using the Bartlett test and then 1-way analysis of variance with the Bonferroni multiple comparison test.. Data were obtained from 20 patients (9 men, 11 women). The average operating times for groups 1, 2, and 3 were 53.1, 46.7, and 49 minutes, respectively. The age range was 18 to 46 years (average, 26.05 yr). The rate of MAP increase from before to during L-I in group 1 was 10.8% (n = 7). The rate of MAP increase from before to during L-I in group 3 was 2.1% (n = 6). Group 3 showed a significantly lower rate of MAP increase during and after L-I compared with group 1 (P < .05).. Remifentanil administration at 0.75 μg/kg/minute stabilized hemodynamics during L-I without major side effects. Results indicated that the standard index of remifentanil administration during L-I should be 0.75 μg/kg/minute when using oxygen, propofol, and remifentanil for general anesthesia.

Topics: Adolescent; Adult; Anesthetics, Intravenous; Arterial Pressure; Blood Loss, Surgical; Body Mass Index; Double-Blind Method; Electroencephalography; Female; Follow-Up Studies; Heart Rate; Humans; Male; Maxilla; Middle Aged; Monitoring, Intraoperative; Operative Time; Osteotomy, Le Fort; Piperidines; Propofol; Prospective Studies; Remifentanil; Young Adult

Bleeding during functional endoscopic sinus surgery is a challenge for the quality of the surgical field for surgeons. This study aimed to evaluate the effect of desmopressin premedication on blood loss and the quality of the surgical field in endoscopic sinus surgery.. A total of 90 American Society of Anesthesiologists physical status I-II patients underwent endoscopic sinus surgery for chronic sinusitis. They were randomly allocated to receive either desmopressin 0.3 μg/kg or saline before the operation. Management of anesthesia was achieved with propofol and remifentanil infusions, with moderate, controlled hypotension. Blood loss and quality of the surgical field were assessed after surgery. Effects of desmopressin on anesthetic requirements and hemodynamic variables were analyzed.. Blood loss was significantly less in the desmopressin group (mean ± SD, 42 ± 8.7 ml) than in the control group (70 ± 9.2 ml, P < 0.001). Surgeons were more satisfied with the surgical field in the desmopressin group than in the control group (median score, 4 [3-5] vs. 7 [6-9], P < 0.001). Requirements for remifentanil and esmolol were lower in the desmopressin group than in the control group.. Premedication with desmopressin 0.3 μg/kg can effectively reduce bleeding during endoscopic sinus surgery.

Topics: Adult; Blood Loss, Surgical; Deamino Arginine Vasopressin; Endoscopy; Female; Hemostatics; Humans; Male; Middle Aged; Piperidines; Propofol; Prospective Studies; Remifentanil; Single-Blind Method; Sinusitis; Young Adult

The aim of the present study was to compare the blood loss with remifentanil-based anesthesia with sevoflurane or isoflurane during orthognathic surgery.. In this randomized controlled clinical trial, the patients who were scheduled for orthognathic surgery were divided into 2 groups: the sevoflurane (Sevo) group and isoflurane (Iso) group. Anesthesia was maintained using end-tidal concentrations of 1.4% sevoflurane or 0.9% isoflurane. Remifentanil was continuously infused at 0.05 to 0.5 μg/kg/min to maintain the mean blood pressure (MBP) at 60 to 65 mm Hg. The intraoperative blood loss was compared between the 2 groups. The Student t test for unpaired samples was used for statistical analysis. P < .05 was considered statistically significant.. The study sample included 19 men and 45 women (n = 64). The mean age was 25 years (range 16 to 50). The intraoperative blood loss tended to be greater in the Iso group (n = 32; 4.79 ± 3.22 mL/kg) than in the Sevo group (n = 32; 4.00 ± 1.98 mL/kg). However, the difference between the 2 groups was not significant.. In a comparison of intraoperative blood loss during remifentanil-based anesthesia with sevoflurane or isoflurane during orthognathic surgery, no difference was observed between the 2 groups.

Topics: Adolescent; Adult; Anesthesia, Dental; Anesthetics, Combined; Anesthetics, Inhalation; Anesthetics, Intravenous; Blood Loss, Surgical; Female; Humans; Isoflurane; Male; Methyl Ethers; Middle Aged; Orthognathic Surgical Procedures; Piperidines; Remifentanil; Sevoflurane; Young Adult

Significant bleeding during functional endoscopic naso-sinusal surgery (FESS) impairs recognition of anatomical references and may negatively affect surgical outcome. Anaesthesia including clonidine as an adjuntive hypotensive agent may reduce intraoperative bleeding.. A randomised comparison of clonidine-based vs remifentanil-based hypotensive anaesthetic regimen was conducted in patients undergoing FESS. The main assessment was the proportion of subjects with Boezaart scores of surgical field bleeding, as blindly assessed from video recordings by a third surgeon not involved in patient care.. A total of 47 subjects underwent FESS and were randomised to clonidine or remifentanil. A significantly lower proportion of patients in the clonidine arm had blindly-assessed Boezaart scores higher than 2, with significantly lower mean blind Boezaart scores at 60 minutes and at 120 minutes. Similar findings were reported by the operating surgeon, and when Wormald and VAS scores were used. Objective estimates of bleeding and the duration of surgery and anaesthesia did not differ between groups.. The use of clonidine- based controlled hypotensive anaesthesia achieves lower surgical field bleeding during FESS.

Topics: Anesthetics, Intravenous; Antihypertensive Agents; Blood Loss, Surgical; Clonidine; Double-Blind Method; Endoscopy; Female; Hemodynamics; Humans; Male; Middle Aged; Paranasal Sinus Diseases; Piperidines; Remifentanil; Treatment Outcome

The aim of this study was to evaluate the effects of premedication with oral atenolol or enalapril, in combination with remifentanil under sevoflurane anesthesia, on intraoperative blood loss by achieving adequate deliberate hypotension (DH) during orthognathic surgery. Furthermore, we investigated the impact thereof on the amount of nitroglycerin (NTG) administered as an adjuvant agent.. Seventy-three patients undergoing orthognathic surgery were randomly allocated into one of three groups: an angiotensin converting enzyme inhibitor group (Group A, n=24) with enalapril 10 mg, a β blocker group (Group B, n=24) with atenolol 25 mg, or a control group (Group C, n=25) with placebo. All patients were premedicated orally 1 h before the induction of anesthesia. NTG was the only adjuvant agent used to achieve DH when mean arterial blood pressure (MAP) was not controlled, despite the administration of the maximum remifentanil dose (0.3 μg kg⁻¹ min⁻¹) with sevoflurane.. Seventy-two patients completed the study. Blood loss was significantly reduced in Group A, compared to Group C (adjusted p=0.045). Over the target range of MAP percentage during DH was significantly higher in Group C than in Groups A and B (adjusted p-values=0.007 and 0.006, respectively). The total amount of NTG administered was significantly less in Group A than Group C (adjusted p=0.015).. Premedication with enalapril (10 mg) combined with remifentanil under sevoflurane anesthesia attenuated blood loss and achieved satisfactory DH during orthognathic surgery. Furthermore, the amount of NTG was reduced during the surgery.

Topics: Administration, Oral; Adrenergic beta-Antagonists; Adult; Aged; Anesthesia, Inhalation; Atenolol; Blood Loss, Surgical; Blood Pressure; Cardiac Output; Double-Blind Method; Enalapril; Female; Heart Rate; Humans; Intraoperative Care; Male; Methyl Ethers; Middle Aged; Orthognathic Surgical Procedures; Piperidines; Premedication; Remifentanil; Sevoflurane; Treatment Outcome

This randomized, double-blind study was designed to assess the effect of perioperative remifentanil with controlled hypotension on intraoperative bleeding, postoperative edema, and ecchymosis.. Fifty-two patients undergoing rhinoplasty were divided into 2 groups. The remifentanil group received 1 µg · kg(-1) intravenously as a bolus before induction of anesthesia, 0.5 to 1 µg · kg(-1) · h(-1) by continuous intravenous infusion during the operation. After anesthesia induction with propofol (2-3 mg · kg(-1)) and fentanyl (1-15 µg · kg(-1)), muscle relaxation was achieved with rocuronium (0.45-0.90 mg · kg(-1)). Mean arterial pressure was maintained at 50 to 60 mm Hg in controlled hypotensive anesthesia achieved using remifentanil infusion. Perioperative hemodynamics and bleeding; early postoperative pain and agitation scale; postoperative first, third, and seventh day edema; and ecchymosis were evaluated. Edema and ecchymosis were evaluated using graded scale from 0 to 4.. Remifentanil reduced mean arterial pressure during the entire operative period and the first 30 minutes postoperatively (P < 0.05 for these comparisons). Intraoperative bleeding also decreased (P < 0.001). There was a significant decrease in edema in both upper and lower eyelid edema on the first and third days in the remifentanil group, although this difference was not detected on the seventh day (P(1upper) = 0.000, P(1lower) = 0.000, P(3upper) = 0.008, and P(3lower) = 0.002). Ecchymosis decreased significantly in both upper and lower eyelids on the first, third, and seventh days in the remifentanil group (P(1upper) = 0.000, P(3upper) = 0.000, P(3upper) = 0.002, P(3lower) = 0.002, P(7upper) = 0.049, and P(7lower) = 0.038). There were no differences in postoperative pain and agitation between 2 groups.. Remifentanil with controlled hypotension may reduce edema and ecchymosis of the upper and lower eyelids, by reducing mean arterial pressure and amount of bleeding in rhinoplasty.

Topics: Adult; Anesthetics, Intravenous; Antihypertensive Agents; Blood Loss, Surgical; Blood Pressure; Double-Blind Method; Ecchymosis; Edema; Eyelid Diseases; Female; Humans; Hypotension, Controlled; Male; Piperidines; Postoperative Complications; Remifentanil; Rhinoplasty; Young Adult

The aim of this study was to compare fentanyl-based versus remifentanil-based anesthesia with regards to the intraoperative hemodynamic stress response and recovery profiles in patients undergoing Le Fort I osteotomy. Seventeen patients were randomly divided into two groups: patients in the F-group received 2 μg/kg fentanyl intravenously followed by an infusion of 0.03-0.06 μg/kg/min, while patients in the R-group received a 0.5 μg/kg bolus of remifentanil followed by an infusion of 0.0625-0.250 μg/kg/min. Mean arterial pressure and heart rate were recorded at the following points: before anesthetic induction, at endotracheal intubation, 5 min after intubation, at incision, just before the osteotomy, during the osteotomy, during the maxillary fracturing, at suturing, at extubation, 5 min after extubation, and then 15 and 30 min postoperatively. Heart rate and mean arterial pressure were significantly lower in the R-group in comparison to the F-group from t1 to t9 (P<0.05). All measured recovery times were significantly shorter in the R-group (P<0.05). The incidence of postoperative side effects was comparable between groups. Remifentanil-based anesthesia is an appropriate alternative to fentanyl during Le Fort I orthognathic surgery; it promotes hemodynamic stability, blunts the stress response to noxious stimuli, and provides a better recovery profile.

Topics: Adolescent; Adult; Anesthesia Recovery Period; Anesthetics, Inhalation; Anesthetics, Intravenous; Antihypertensive Agents; Arterial Pressure; Blood Loss, Surgical; Female; Fentanyl; Follow-Up Studies; Heart Rate; Humans; Intubation, Intratracheal; Labetalol; Male; Maxilla; Methyl Ethers; Monitoring, Intraoperative; Orthognathic Surgical Procedures; Osteotomy, Le Fort; Pain, Postoperative; Piperidines; Postoperative Nausea and Vomiting; Prospective Studies; Remifentanil; Sevoflurane; Single-Blind Method; Wound Closure Techniques; Young Adult

The aim of this retrospective study was to evaluate the efficacy of dexamethasone with controlled hypotension on intraoperative bleeding and postoperative morbidity in rhinoplasty.. Sixty rhinoplasty patients required hump resection and lateral osteotomy were included in this study. The patients were randomized into four groups. In group I (n=15), a single dose of 10mg/kg dexamethasone was intravenously administered at the beginning of the operation. In group II (n=15), the patients were given 2 doses of 10mg/kg intravenously dexamethasone at the beginning of the operation, and 24 hours after the operation. In group III (n=15), 3 doses of 10mg/kg intravenously dexamethasone were given at the beginning of the operation, before osteotomy and 24 hours after the operation. Group IV (n=15) was assigned as control group and the patients were neither administered dexamethasone nor applied hypotension. All cases in groups I, II and III were operated under controlled hypotension. Systolic arterial pressure was aimed to keep between 65 and 75 mmHg for controlled hypotensive anaesthesia. Controlled hypotension was achieved by a remifentanil infusion of 0.1-0.5 microg/kg/min, following a bolus of 1 microg/kg. Degree of eyelid oedema and periorbital soft-tissue ecchymosis was evaluated separately using a scale of 0-4. Intraoperative blood loss was recorded for each patient. Patients were evaluated at 24 hours and postoperative days 2, 5, 7, and 10.. In groups I, II and III, intraoperative bleeding was more decreased and the operation time was significantly shorter compared with control group (P<0.001). Eyelid oedema and periorbital ecchymosis were significantly decreased in groups I, II and III at the following postoperative 7 and 10 days (P<0.001). There was statistically significant difference between group III and other groups at the postoperative 5 and 7 days in lower eyelid oedema (P<0.001), upper and lower eyelid ecchymosis (P<0.001 and 0.004, respectively). There were no postoperative complications with using steroid in any of the groups.. Three doses of dexamethasone with controlled hypotension considerably reduced postoperative morbidities of rhinoplasty with osteotomy as well as intraoperative bleeding. Thus, in group III receiving 3 doses of steroid, when compared to other groups, more uneventful postoperative period were provided for surgeon and the patients.

Topics: Adult; Anti-Inflammatory Agents; Blood Loss, Surgical; Blood Pressure; Dexamethasone; Ecchymosis; Edema; Eyelid Diseases; Female; Follow-Up Studies; Glucocorticoids; Humans; Hypnotics and Sedatives; Hypotension, Controlled; Male; Nasal Cartilages; Nasal Septum; Operative Time; Osteotomy; Patient Satisfaction; Piperidines; Postoperative Complications; Premedication; Remifentanil; Retrospective Studies; Rhinoplasty; Treatment Outcome; Young Adult

The aim of the study was to assess the effect of three different types of anaesthesia on perioperative bleeding control and to analyse the mean arterial blood pressure and heart rate in patients undergoing endoscopic paranasal sinus surgery. Ninety patients (30 women and 60 men, aged 18-85 years) scheduled to undergo functional endoscopic sinus surgery in the years 2008-2010 were identified as candidates for inclusion in the study. Patients were randomly assigned to one of three groups (30 patients each) according to the type of general anaesthesia to be administered. Groups I and II both received inhalation anaesthesia (sevoflurane for sedation) and intravenous anaesthesia (fentanyl in group I, remifentanil in group II). Anaesthesia was delivered solely via intravenous route (TIVA) in group III, with propofol used for sedation and remifentanil for analgesia. Blood pressure and heart rate were monitored during surgery and post-surgically for 4 h. Mean anaesthesia duration in groups I, II and III was 108.7 ± 20.8, 112.6 ± 22.2 and 103.7 ± 17.5 min and the surgery duration was 71.3 ± 16.7, 78.8 ± 24.2 and 66.5 ± 15.5 min, respectively. Mean blood loss during surgery was 365.0 ± 176.2, 340.0 ± 150.5 and 225.0 ± 91.7 ml, with a mean blood loss rate of 5.1 ± 2.4, 4.5 ± 2.2 and 3.4 ± 1.1 ml/min in groups I, II and III, respectively. Technologically advanced control of the drug dose with the TIVA technique allows for better control of perioperative bleeding.

Topics: Adult; Aged; Anesthesia, Inhalation; Anesthesia, Intravenous; Anesthetics, Inhalation; Anesthetics, Intravenous; Blood Loss, Surgical; Blood Pressure; Endoscopy; Female; Fentanyl; Heart Rate; Humans; Male; Methyl Ethers; Middle Aged; Paranasal Sinuses; Piperidines; Propofol; Remifentanil; Sevoflurane

We compared anesthesia with sevoflurane-remifentanil hydrochloride (SR) to total intravenous anesthesia with propofol-remifentanil hydrochloride (PR) in patients undergoing endoscopic sinus surgery for chronic rhinosinusitis in terms of sinonasal mucosal blood flow, the surgical field visualization score, and blood loss.. We performed a double-blinded prospective study at a tertiary care center in 23 adults scheduled to undergo endoscopic sinus surgery for chronic rhinosinusitis. The patients were randomized to receive SR or PR. The sinonasal mucosal blood flow was measured by optical rhinometry. The surgical field visualization score was based on the Boezaart scale.. The groups had similar clinical characteristics. During the 60- to 90-minute and 90- to 120-minute operative time windows, the blood flow was significantly greater in the PR group than in the SR group (p = 0.04 and p = 0.03, respectively). The amounts of blood loss in the PR and SR groups were 152.9 +/- 161.3 mL and 355.9 +/- 393.4 mL, respectively (p = 0.12). The median ratios of the surgical field visualization score to the number of sinuses operated on in the PR and SR groups were 2.1 and 1.8, respectively (p = 0.52).. The intraoperative blood flow, as determined by optical rhinometry, was significantly greater with anesthesia with PR than with anesthesia with SR, 1 hour into the procedure; however, this difference did not translate into differences in the amounts of operative blood loss or in the surgical field visualization scores.

Topics: Adult; Aged; Anesthesia, Inhalation; Anesthesia, Intravenous; Anesthetics, Inhalation; Anesthetics, Intravenous; Blood Loss, Surgical; Double-Blind Method; Endoscopy; Female; Humans; Male; Methyl Ethers; Middle Aged; Paranasal Sinuses; Pilot Projects; Piperidines; Propofol; Prospective Studies; Remifentanil; Rhinitis; Sevoflurane; Sinusitis

In our study, desflurane was hypothesized to reduce blood loss more than sevoflurane, both used with targeted mild controlled hypotension.. A total of 20 American Society of Anesthesiologists Class I patients undergoing maxillofacial elective surgery for maxillary and mandibular osteotomies were randomized to a desflurane group or a sevoflurane group. Anesthesia was performed with an end tidal value of the inhaled agent to obtain a bispectral index value <30 but without burst-suppression patterns (minimal alveolar concentration age-corrected between 0.7 and 0.9). Remifentanil was administered at a dose of 0.5 microg x kg(-1) x min(-1) to obtain analgesia and a <2 surgical field level in Fromme's modified scale. Sodium-nitroprusside was administered on demand to have a surgical field level of <2 when the anesthesia plan was not sufficient to achieve this target. The minimal value of the mean arterial pressure achievable was 60 mm Hg.. In the desflurane group, blood loss was more restricted. The hypotensive drug was used in 8 patients in the sevoflurane group and 2 patients in the desflurane group.. Anesthesia with desflurane can reduce blood loss and could give an acceptable surgical field with mild controlled hypotension and with a substantial reduction in the vasoactive drug requirement. These data need to be assessed with an enlargement of the statistical sample.

Topics: Adolescent; Adult; Analgesics, Opioid; Anesthetics, Inhalation; Blood Loss, Surgical; Blood Pressure; Desflurane; Elective Surgical Procedures; Electroencephalography; Female; Humans; Hypotension, Controlled; Isoflurane; Male; Mandible; Maxilla; Methyl Ethers; Monitoring, Intraoperative; Nitroprusside; Orthognathic Surgical Procedures; Osteotomy; Piperidines; Remifentanil; Sevoflurane; Time Factors; Vasodilator Agents; Young Adult

Endoscopic sinus surgery (ESS) is often affected by intra-nasal bleeding, which can be influenced by various anaesthetics and preoperative conditions. This study compared the surgical condition and the amount of intra-nasal bleeding between patients given sevoflurane/remifentanil (SR) and propofol/remifentanil (PR) anaesthesia.. ASA I or II patients undergoing ESS were randomly assigned to group SR (n=20) or group PR (n=20). The extent of the preoperative surgical lesion was classified as high (> 12) and low Lund-Mackay (LM) (< or = 12) scores according to the computed tomography findings. The amount of intraoperative blood loss was calculated from the patients' haemoglobin (Hb) and the amount of blood in the suction canister. The surgeons rated the visibility of the surgical field on a numeric rating scale (NRS).. In the high-LM score patients, the median (1st/3rd quartiles) blood loss for the SR and PR groups was 135 (121/222) and 19 (8/71) ml h(-1), respectively (P<0.01), and the mean (SD) of NRS was 5.8 (2.3) and 2.3 (1.0), respectively (P<0.05). However, in patients with low-LM score, both blood loss and NRS scores were not different between groups SR and PR.. In the high-LM score patients, PR anaesthesia results in less blood loss and a better surgical conditions for ESS than SR anaesthesia.

Topics: Adult; Anesthetics, Inhalation; Anesthetics, Intravenous; Blood Loss, Surgical; Endoscopy; Female; Humans; Male; Methyl Ethers; Middle Aged; Paranasal Sinuses; Piperidines; Propofol; Prospective Studies; Remifentanil; Severity of Illness Index; Sevoflurane; Sinusitis; Tomography, X-Ray Computed

To compare the effect of remifentanil combined with desflurane or isoflurane on the quality of the operative field and surgical conditions, blood loss, and recovery during tympanoplasty or endoscopic sinus surgery.. Randomised, double-blinded clinical study.. Sixty-four patients were scheduled for elective tympanoplasty or endoscopic sinus surgery. The patients were randomly divided into two groups: desflurane or isoflurane. After anaesthesia induction, all patients received a continuous remifentanil infusion of 0.2-0.5 microg/kg/min until a mean arterial pressure of 65-75 mmHg was achieved. Heart rate and mean arterial pressure were recorded throughout anaesthesia. Blood loss was measured at the end of surgery. Achievement of a bloodless operative field was rated on a 100 mm visual analogue scale. Following completion of surgery, the time to extubation and to achievement of an Aldrete score of nine or more was recorded.. Sixty-three patients were evaluated. The total dose of remifentanil and the total blood loss were similar in both groups (p > 0.05). Time to extubation and to an Aldrete score of nine or more for the desflurane group was significantly less than for the isoflurane group (p 0.05).. Although desflurane and isoflurane both enabled good surgical conditions (in terms of quality of operative field) and convenient induction of hypotension for tympanoplasty and endoscopic sinus surgery, the recovery characteristics of desflurane were better than those of isoflurane. Therefore, desflurane may be preferable to isoflurane in such circumstances.

Topics: Adolescent; Adult; Anesthesia Recovery Period; Anesthetics, Combined; Blood Loss, Surgical; Desflurane; Double-Blind Method; Endoscopy; Female; Heart Rate; Humans; Hypotension; Isoflurane; Male; Middle Aged; Nasal Polyps; Piperidines; Remifentanil; Sinusitis; Treatment Outcome; Tympanoplasty

Controlled hypotension is used to improve surgical conditions during microscopic and endoscopic sinus surgery. Several drug combinations are suitable to provide deep and predictable level of anaesthesia combined with an exact control of intraoperative blood pressure. However, only little is known about the relative importance of the level of hypnosis on the one hand and analgesia on the other hand.. Prospective, randomized, patient and observer-blinded study.. All 100 consecutive patients received a balanced anaesthesia technique using desflurane and remifentanil. Anaesthesia was desflurane-accentuated with remifentanil-supplementation (DARS-group: 1 MAC desflurane; remifentanil: 0.2 microg x kg(-1) x min(-1)) or remifentanil-accentuated with desflurane-supplementation (RADS-group: desflurane: 0.5 MAC; remifentanil: 0.4 microg x kg(-1) x min(-1)). Administration of anaesthetics performed to maintain a sufficient level of anaesthesia and to keep mean arterial pressure between 60 and 70 mmHg (8-9.3 hPa). The attending ENT-surgeons were unaware of the type of anaesthesia and rated general surgical conditions and the dryness of the operating site on a visual analogue scale (0-10 cm) and on a verbal rating scale immediately after surgery.. Blood pressure and heart rate was not different between the two groups. Dryness of the operating site was rated significantly better (p < 0.0001) in the DARS-group (median; 25th/75th-percentile: 2.0; 1.5-3.5 vs. RADS-group: 2.6; 2.0-4.0) but the overall rating of the surgical conditions did not differ between the groups (DARS-group: 2.0; 1.0-2.4 vs. RADS-group: 2.2; 1.5-3.2). Immediate postoperative recovery times were increased in the RADS-group, but there was no difference with respect to fit-for-discharge criteria one hour after surgery.. Balanced anaesthesia using high dose of desflurane offers small but statistically significant advantages with respect to dryness of the operating site compared to an opioid-accentuated anaesthesia technique. However, since the opioid-accentuated anaesthetic group had a faster immediate recovery both techniques are equally effective for microscopic and endoscopic sinus surgery.

Topics: Adult; Anesthesia Recovery Period; Anesthetics, Combined; Anesthetics, Inhalation; Anesthetics, Intravenous; Blood Loss, Surgical; Blood Pressure; Desflurane; Electroencephalography; Endoscopy; Female; Heart Rate; Humans; Hypotension, Controlled; Intraoperative Care; Isoflurane; Male; Microsurgery; Middle Aged; Patient Discharge; Piperidines; Prospective Studies; Remifentanil; Single-Blind Method; Sinusitis

We compared the efficacy of remifentanil and the combination of alfentanil and sodium nitroprusside on controlled hypotension and bleeding at surgical site.. Thirty ASA I-II patients undergoing tympanoplasty were randomly assigned to remifentanil and alfentanil-sodium nitroprusside groups, equal in number. Anesthesia was induced with remifentanil or alfentanil combined with propofol and rocuronium, and maintained with remifentanil or alfentanil-sodium nitroprusside infusions combined with propofol. All patients were ventilated with a mixture of 33% O2 and 66% N2O. Invasive mean arterial blood pressure, heart rate, peripheral oxygen saturation, the amount of bleeding at surgical site, and blood gas values were recorded.. Controlled hypotension was achieved at a target mean arterial pressure of 60+/-5 mmHg in both groups. Compared to the baseline levels, heart rate values were lower in the remifentanil group (p<0.05), and similar in the sodium nitroprusside group (p>0.05). The amount of bleeding and the dryness of the surgical site were similar in two groups. PaCO2 and pH values differed significantly between the two groups at perioperative 1 and 2 hours and in the postoperative 30th minute (p<0.05), but the difference was not clinically significant.. Our results suggest that remifentanil is effective in obtaining controlled hypotension without an additional potent hypotensive agent and provides appropriate surgical conditions by reducing the amount of bleeding.

Topics: Adult; Alfentanil; Analgesics, Opioid; Antihypertensive Agents; Blood Loss, Surgical; Blood Pressure; Drug Therapy, Combination; Ear, Middle; Female; Hemostatic Techniques; Humans; Hypotension, Controlled; Male; Nitroprusside; Piperidines; Postoperative Hemorrhage; Remifentanil; Treatment Outcome; Tympanoplasty

A short hospital stay is nowadays desirable and affordable for a wide range of surgical pathology, respecting safety of care and home discharge. In the present study, the Authors investigated the use of TIVA with propofol/remifentanil during microsurgical vertebral disc resection to maintain a controlled vascular hypotension for bloodless surgical field aiming to reduce the operating time and consequently recovery room length of stay and morbility related to anaesthesia.. The study took place in a 300 bed Orthopaedics hospital over a period of 3 months and 50 ASA I-II patients were enrolled in this trial; further data are presented for comparison of 50 ASA I-II patients homogeneous for age and sex to the studied population, operated under a standard TIVA with propofol and boluses of fentanyl. Duration of anaesthesia and surgery, time for awakening after cessation of TIVA, incidence of postoperative nausea and vomiting (PONV), amount and quality of postoperative analgesia, length of stay in the recovery room are reported in statistical presentation.. Time of surgery and anaesthesia were reduced in the remifentanil group compared with the fentanyl group, thanks to an easily reachable and durable state of controlled hypotension in the first group without the use of any other drug. The recovery profile was shorter in the remifentanil group the drug being rapidly metabolised by plasma cholinesterase.. No difference occurred between the two groups regarding quality and amount of postoperative analgesia, while PONV presented more in the fentanyl group and shivering more in the remifentanil group.

Topics: Adult; Ambulatory Surgical Procedures; Anesthesia, Intravenous; Anesthetics, Intravenous; Blood Loss, Surgical; Female; Fentanyl; Hemodynamics; Humans; Intervertebral Disc; Length of Stay; Male; Middle Aged; Neurosurgical Procedures; Pain, Postoperative; Piperidines; Postoperative Nausea and Vomiting; Remifentanil

This prospective randomized study investigated the influence of normotensive and hypotensive general anesthesia on platelet aggregability, intraoperative blood loss and parameters of plasmatic coagulation during extensive orthognathic surgery. A total of 30 patients were randomly allocated for either normotensive anesthesia maintained by continuous infusion of propofol and remifentanil (NORMO, n=10) or hypotensive anesthesia, whereby hypotension was induced by increasing the infusion rate of remifentanil (HYPO-R, n=10) or by administration of nitroglycerin (HYPO-N, n=10). Whole blood platelet aggregability was significantly reduced during hypotension compared to normotensive anesthesia (P<.01, HYPO-N and HYPO-R vs. NORMO). Mean arterial blood pressure during hypotension correlated well with adenosinediphosphate- (R=.712, P<.001) and collagen-induced platelet aggregability (R=.685, P<.001). Within hypotensive study groups, postoperative fibrinogen levels were significantly different, whereas intraoperative platelet aggregability, postoperative platelet count, prothrombin time, activated partial thromboplastin time and antithrombin levels were not different. Normotensive anesthesia, however, caused significant decreases in platelet count (-29%), prothrombin time (-24%), fibrinogen (-41%) and antithrombin (-28%) and a significant prolongation in activated partial thromboplastin time (+21%) and thrombin time (+18%). There was a trend to reduced intraoperative blood loss in hypotensive study groups; however, differences were not significant. In conclusion, induced hypotension--independent of substances used for induction of hypotension--reduces intraoperative platelet aggregability, subsequently protecting the coagulation system against subclinical consumption coagulopathy. Induced hypotension-caused platelet dysfunction does not lead to an increased intraoperative blood loss, but quite on the contrary shows a trend to reduced intraoperative blood loss, possibly by preventing platelet-induced subclinical consumption coagulopathy.

Topics: Adult; Anesthesia; Anesthetics, Intravenous; Biomarkers; Blood Loss, Surgical; Female; Hemostasis; Humans; Hypotension; Male; Nitroglycerin; Oral Surgical Procedures; Piperidines; Platelet Aggregation; Propofol; Remifentanil

Remifentanil is reported to reduce oral tissue blood flow. We performed a retrospective investigation using logistic regression analysis of anesthesia records to investigate whether the use of remifentanil infusion in a balanced anesthesia technique was useful as a primary technique to reduce blood loss during orthognathic surgery. Subjects were 80 patients who underwent Le Fort I osteotomy and sagittal split ramus osteotomy of the mandible. The variables included gender, age, weight, type of maintenance anesthetic, type and dose or infusion rate of opioid, mean systolic blood pressure (SBP-mean), coefficient of variation of systolic blood pressure (CVSBP) during surgery, mean heart rate (HR-mean), duration of surgery, total blood loss, volume of infusion used, amount of local anesthetic used, body temperature, and urine output. Gender, type of maintenance anesthetic, type of opioid, SBP-mean, CVSBP, HR-mean, and duration of surgery were used as candidates for independent variables. Logistic regression analysis was performed for the selected independent variables with the total blood loss as the dependent variable. The factors associated with the reduction of blood loss were the use of remifentanil (odds ratio, 3.112; 95% CI, 1.166-8.307; P = .023) and smaller CVSBP (odds ratio, 2.747; 95% CI, 1.07-7.053; P = .036). Use of remifentanil and smaller CVSBP were associated with a reduction of blood loss during orthognathic surgery.

Topics: Adolescent; Adult; Anesthesia, General; Anesthetics, Intravenous; Blood Loss, Surgical; Blood Pressure; Chi-Square Distribution; Female; Humans; Infusions, Intravenous; Logistic Models; Male; Mandible; Middle Aged; Odds Ratio; Orthognathic Surgical Procedures; Osteotomy; Piperidines; Remifentanil; Retrospective Studies; Risk Factors; Treatment Outcome; Young Adult

This study retrospectively compared blood loss during sagittal split ramus osteotomy in patients receiving propofol-remifentanil (R group) and those receiving propofol-fentanyl (F group). All patients underwent sagittal split ramus osteotomy under general anesthesia during the 3-year 4-month period between October 2007 and February 2011 in an operating room at Tokyo Dental College Suidobashi Hospital. Blood loss in the R group was significantly less than that in the F group. Mean arterial pressure and heart rate, measured at 20 and 15 min after tracheal intubation, respectively, were both lower in the R group. No marked change was observed in blood pressure in the R group under general anesthesia, however. Volume of urine was also larger in the R group. The results of this study suggest that remifentanil is effective in reducing intraoperative blood loss during sagittal split ramus osteotomy.

Topics: Adult; Anesthesia, General; Arterial Pressure; Blood Loss, Surgical; Female; Fentanyl; Heart Rate; Humans; Male; Osteotomy, Sagittal Split Ramus; Piperidines; Propofol; Remifentanil; Retrospective Studies; Tokyo; Urine

Crouzon syndrome is a rare, autosomal dominant disease from a fibroblast growth factor receptor 2 gene mutation, characterized by premature craniosynostosis, hypertelorism, orbital proptosis, psittichorina, hypoplastic maxilla, and mandibular prognathism. We present an adult 32-year-old Crouzon syndrome patient who underwent an elective High Le Fort I and bilateral split sagittal osteotomy for midface advancement with a background of jaw malocclusion and obstructive respiratory symptoms. The operation features a potential dynamic movement of the secured airway in the surgical field and close proximity to exposed ocular structures. Permissive hypotensive anesthesia was employed to improve the surgical field and reduce intraoperative blood loss and dose of long-acting opioids. He was extubated at the end of an uneventful surgery and was monitored in the high dependency overnight before he was discharged to the general ward. Perioperative issues include potential difficult airway management; ocular, auditory, and neurological injury prevention; surgery-specific anesthetic technique; and postoperative analgesia. Understanding the multisystemic issues facilitates the dynamic anesthetic management during surgery. Good communication among the multidisciplinary team is essential to ensure a successful operation and uneventful recovery.

Topics: Adult; Airway Management; Airway Obstruction; Analgesia, Patient-Controlled; Anesthetics, Intravenous; Atracurium; Blood Loss, Surgical; Craniofacial Dysostosis; Humans; Hypotension, Controlled; Intubation, Intratracheal; Male; Malocclusion; Morphine; Narcotics; Neuromuscular Nondepolarizing Agents; Orthognathic Surgical Procedures; Osteotomy, Le Fort; Osteotomy, Sagittal Split Ramus; Piperidines; Prognathism; Remifentanil

To test the compensatory role of endothelin-1 when acute blood loss is superimposed on anaesthesia, by characterizing the effect of systemic endothelin receptor subtype A (ET(A)) blockade on the haemodynamic and hormonal responses to haemorrhage in dogs anaesthetized with xenon/remifentanil (X/R) or isoflurane/remifentanil (I/R).. Prospective experimental randomized controlled study.. Six female Beagle dogs, 13.4 +/- 1.3 kg.. Animals were anaesthetized with remifentanil 0.5 microg kg(-1) minute(-1) plus either 0.8% isoflurane (I/R) or 63% xenon (X/R), with and without (Control) the systemic intravenous endothelin receptor subtype A antagonist atrasentan (four groups, n = 6 each). After 60 minutes of baseline anaesthesia, the dogs were bled (20 mL kg(-1)) over 5 minutes and hypovolemia was maintained for 1 hour. Continuous haemodynamic monitoring was performed via femoral and pulmonary artery catheters; vasoactive hormones were measured before and after haemorrhage.. In Controls, systemic vascular resistance (SVR), vasopressin and catecholamine plasma concentrations were higher with X/R than with I/R anaesthesia at pre-haemorrhage baseline. The peak increase after haemorrhage was higher during X/R than during I/R anaesthesia (SVR 7420 +/- 867 versus 5423 +/- 547 dyne seconds cm(-5); vasopressin 104 +/- 23 versus 44 +/- 6 pg mL(-1); epinephrine 2956 +/- 310 versus 177 +/- 99 pg mL(-1); norepinephrine 862 +/- 117 versus 195 +/- 33 pg mL(-1), p < 0.05). Haemorrhage reduced central venous pressure from 3 +/- 1 to 1 +/- 1 cm H(2)O (I/R, ns) and from 8 +/- 1 to 5 +/- 1 cm H(2)O (X/R, p < 0.05), but did not reduce mean arterial pressure, nor cardiac output. Atrasentan did not alter the haemodynamic and hormonal response to haemorrhage during either anaesthetic protocol.. Selective ET(A) receptor blockade with atrasentan did not impair the haemodynamic and hormonal compensation of acute haemorrhage during X/R or I/R anaesthesia in dogs.

Topics: Anesthesia; Anesthesia, Inhalation; Anesthesia, Intravenous; Anesthetics, Inhalation; Anesthetics, Intravenous; Animals; Atrasentan; Blood Loss, Surgical; Catecholamines; Dog Diseases; Dogs; Endothelin A Receptor Antagonists; Endothelin-1; Epinephrine; Female; Hemodynamics; Hemorrhage; Isoflurane; Norepinephrine; Piperidines; Pyrrolidines; Remifentanil; Time Factors; Vascular Resistance; Vasopressins; Xenon

To evaluate whether remifentanil based general anesthesia combined with epidural analgesia for postoperative pain, has any advantages with respect to consumption of drugs, blood loss, quality of pain control, hemodynamic profile, in major abdominal surgery, as compared to other combined techniques.. A retrospective study based on chart reviews of patients who have undergone colectomy, radical cystectomy and radical prostatectomy over one year period in our Institution, operated under combined regional-general anesthesia. Twenty-six patients were analyzed and were divided into three groups according to the type of anesthesia received. Group A: combined general-epidural for per-operative and postoperative pain (10 patients). Group B: combined spinal-general anesthesia (8 patients) post-operative analgesia consisted of parenteral mepiridine and paracetamol. Group C: remifentanil based general anesthesia followed by epidural for postoperative analgesia (8 patients).. The demographic data, age and M/F distribution were comparable in the three groups. The remifentanil group showed less utilization of muscle relaxant (Cisatracurium) with respect to other groups (p < 0.001). The amount of intraoperative blood loss was not significantly different among the three groups. The efficacy of the postoperative epidural analgesia was demonstrated by the minimal utilization of analgesics (p < 0.05 and 0.01) in group A and C as compared to group B. In the group of remifentanil, the blood pressure was more stable and maintained at a systolic of 80-100 mmHg as compared to initial hypotension mainly in group C.. The use of remifentanil based general anesthesia offers the advantage of non-accumulation of drugs and hemodynamic stability. Post-operative analgesia can be provided by epidural route which proved to be satisfactory in the remifentanil group. The effect on blood loss was not conclusive in this study.

Topics: Abdomen; Adult; Aged; Analgesia, Epidural; Anesthesia, Conduction; Anesthesia, General; Anesthetics, Intravenous; Anesthetics, Local; Blood Loss, Surgical; Blood Pressure; Dose-Response Relationship, Drug; Female; Heart Rate; Humans; Male; Middle Aged; Neuromuscular Blocking Agents; Pain Measurement; Pain, Postoperative; Piperidines; Preanesthetic Medication; Remifentanil; Retrospective Studies

Optimal vision is essential for successful endonasal sinus surgery. Beside topical vasoconstriction general anaesthesia can contribute to reduce intraoperative bleeding.. For many years deliberate hypotension was used to prevent intraoperative bleeding. The intentional reduction of systolic blood pressure to 50-60 mm Hg was achieved by the use of Sodium Nitroprusside alone or in combination with other vasoactive agents. However, intraoperative bleeding is not affected by this technique unless the systolic blood pressure falls below 60 mm Hg which can cause serious side effects for the patient. Recently, there is growing evidence that not only systolic blood pressure but also a low heart rate (< 60 beats per minute) can minimize surgical bleeding. With the introduction of total intravenous anaesthesia (TIVA) by the use of Propofol and Remifentanyl an anaesthetic technique has been established which fulfils the haemodynamic requirements in endonasal sinus surgery in many regards. The inhibiting effects on the cardiovascular system of these drugs alone can lead to a reduced bleeding. TIVA allows the reduction of the systolic blood pressure to 60 mm Hg as well as the heart rate below 60 beats per minute. If necessary it can be supported by vasoactive agents of which betablockers have a theoretical advantage.. For general anaesthesia in endonasal sinus surgery Sodium Nitroprusside is no longer recommended. Instead a TIVA using Propofol and Remifentanil should be used.

Topics: Anesthesia, Intravenous; Anesthetics, Intravenous; Blood Loss, Surgical; Blood Pressure; Cardiovascular System; Heart Rate; Humans; Hypotension, Controlled; Nitroprusside; Paranasal Sinuses; Piperidines; Propofol; Remifentanil; Vasodilator Agents

Topics: Anesthesia, Closed-Circuit; Blood Loss, Surgical; Humans; Liver; Piperidines; Propofol; Remifentanil

We examined the adjunctive effect of a novel factor Xa inhibitor, YM-60828, on vessel patency and blood loss from the operation site after successful thrombolysis with a modified tissue-type plasminogen activator (moPA) in an electrically-induced carotid artery thrombosis model in rats. Five minutes after the induction of occlusive thrombus, a test drug (YM-60828, argatroban, heparin or saline) was administered by i.v. bolus injection followed by continuous infusion. Thrombolysis was induced with moPA by i.v. bolus injection at a dose of 650,000 IU/ kg. YM-60828 at 1 mg/kg i.v. followed by 3 mg/kg/h significantly prevented reocclusion, increased the duration of patency, and improved vessel patency after successful thrombolysis without any significant increase in blood loss from the operation site. Argatroban at 1 mg/kg i.v. followed by 3 mg/kg/h and heparin at 300 U/kg i.v. followed by 150 U/kg/h also significantly improved these parameters, but were accompanied by a significant increase in blood loss. These results suggest that the factor Xa inhibitor YM-60828 may be a potent and useful adjunctive agent with a lower risk of bleeding complications than argatroban and heparin in thrombolytic therapy.

Topics: Animals; Anticoagulants; Arginine; Blood Loss, Surgical; Carotid Arteries; Carotid Artery Thrombosis; Drug Evaluation, Preclinical; Hemorrhage; Heparin; Male; Naphthalenes; Pipecolic Acids; Piperidines; Rats; Recurrence; Reperfusion; Serine Proteinase Inhibitors; Sulfonamides; Thrombolytic Therapy; Time Factors; Tissue Plasminogen Activator