A comparison between total intravenous anaesthesia using a propofol/alfentanil mixture and an inhalational technique for laparoscopic gynaecological sterilization

Prospective evaluation of remifentanil-propofol mixture for total intravenous anesthesia: A randomized controlled study

Application of total intravenous anesthesia (TIVA) may be considered as unpractical when compared with inhalational anesthesia. Although it is mostly not recommended, mixing intravenous agents is popular in clinical practice. The aim of the present study was to investigate the suitability of using remifentanil-propofol mixture (MIXTIVA) for TIVA. Adult patients with an American Society of Anesthesiologists grade of I-II scheduled for elective thyroidectomy were randomly allocated to 3 groups (n=32 for each) to receive TIVA with remifentanil and propofol infusions separately (control group, Group I) or with MIXTIVA infusion that contained remifentanil/propofol at a proportion of 2/1,000 or 3/1,000 (remifentanil concentration, 20 or 30 µg/ml in 1% propofol in Group II or Group III, respectively). The extubation time (the primary outcome of the study), the orientation time and number of patients in whom intraoperative hypotension, hypertension or bradycardia episodes were encountered during anesthesia were comparable among the groups. The mean remifentanil infusion rate in Group III was significantly higher than that in the other groups. The mean propofol infusion rates and mean bispectral index (BIS) scores during anesthesia were comparable among groups. Hypotension accompanied with a high BIS was encountered in one patient in Group III. In conclusion, compared to the standard TIVA technique using separate drug infusions, MIXTIVA infusion used for thyroidectomies did not result in any statistically significant difference in recovery and clinical outcomes. This technique may be considered as a practical implementation for busy ambulatory centers performing general anesthesia. The present study was retrospectively registered at clinicaltrials.gov (trial registration no. NCT04394897).

Impact of extending prevention of postoperative nausea and vomiting for cancer surgical patients in the PACU: a before and after retrospective study

Backgrounds

Procedures for Postoperative Nausea and Vomiting (PONV) prevention are mostly based on identification of the risk factors before administering antiemetic drugs. The purpose of this study was to evaluate the impact of the extended use of antiemetic on the PONV in the Postanesthetic Care Unit (PACU).

Methods

Two separate 4-year periods (2007...2010, P1, and (2015...2018, P2) were evaluated. During P1, the protocol consisted of dexamethasone and droperidol for patients with a locally adapted high PONV score, followed by ondansetron for rescue in the PACU. For Period 2, dexamethasone (8 mg) and ondansetron (4 mg) were administered in patients under general or regional anesthesia, or sedation longer than 30 minutes, while droperidol (1.25 mg) in rescue was injected in cases of PONV in the PACU. An Anesthesia Information Management System was used to evaluate the intensity score of PONV (1 to 5), putative compliance, sedation, and perioperative opioid consumption upon arrival in the PACU.

Results

A total of 27,602 patients were assessed in P1 and 36,100 in P2. The administration of dexamethasone and ondansetron increased several fold (p < 0.0001). The high PONV scores were more improved in P2 than in P1, with scores (3+4+5) for P1 vs. P2, p < 0.0001. Overall, 99.7% of the patients in P2 were asymptomatic at discharge. Morphine consumption decreased from 6.9..1.5 mg in P1 to 3.5 .. 1.5 mg in P2 (p < 0.0001).

Discussion

The extension of pharmacological prevention of PONV was associated with a decrease in the intensity of severe PONV. However, uncertainty regarding confounding factors should not be ignored.

IRB

n.. 92012/33465

Anaesthetic interventions for prevention of awareness during surgery

BACKGROUND

General anaesthesia is usually associated with unconsciousness. 'Awareness' is when patients have postoperative recall of events or experiences during surgery. 'Wakefulness' is when patients become conscious during surgery, but have no postoperative recollection of the period of consciousness.

OBJECTIVES

To evaluate the efficacy of two types of anaesthetic interventions in reducing clinically significant awareness:- anaesthetic drug regimens; and- intraoperative anaesthetic depth monitors.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, ISSUE 4 2016); PubMed from 1950 to April 2016; MEDLINE from 1950 to April 2016; and Embase from 1980 to April 2016. We contacted experts to identify additional studies. We performed a handsearch of the citations in the review. We did not search trial registries.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) of either anaesthetic regimens or anaesthetic depth monitors. We excluded volunteer studies, studies of patients prior to skin incision, intensive care unit studies, and studies that only randomized different word presentations for memory tests (not anaesthetic interventions).Anaesthetic drug regimens included studies of induction or maintenance, or both. Anaesthetic depth monitors included the Bispectral Index monitor, M-Entropy, Narcotrend monitor, cerebral function monitor, cerebral state monitor, patient state index, and lower oesophageal contractility monitor. The use of anaesthetic depth monitors allows the titration of anaesthetic drugs to maintain unconsciousness.

DATA COLLECTION AND ANALYSIS

At least two authors independently scanned abstracts, extracted data from the studies, and evaluated studies for risk of bias. We made attempts to contact all authors for additional clarification. We performed meta-analysis statistics in packages of the R language.

MAIN RESULTS

We included 160 studies with 54,109 enrolled participants; 53,713 participants started the studies and 50,034 completed the studies or data analysis (or both). We could not use 115 RCTs in meta-analytic comparisons because they had zero awareness events. We did not merge 27 of the remaining 45 studies because they had excessive clinical and methodological heterogeneity. We pooled the remaining 18 eligible RCTs in meta-analysis. There are 10 studies awaiting classification which we will process when we update the review.The meta-analyses included 18 trials with 36,034 participants. In the analysis of anaesthetic depth monitoring (either Bispectral Index or M-entropy) versus standard clinical and electronic monitoring, there were nine trials with 34,744 participants. The overall event rate was 0.5%. The effect favoured neither anaesthetic depth monitoring nor standard clinical and electronic monitoring, with little precision in the odds ratio (OR) estimate (OR 0.98, 95% confidence interval (CI) 0.59 to 1.62).In a five-study subset of Bispectral Index monitoring versus standard clinical and electronic monitoring, with 34,181 participants, 503 participants gave awareness reports to a blinded, expert panel who adjudicated or judged the outcome for each patient after reviewing the questionnaires: no awareness, possible awareness, or definite awareness. Experts judged 351 patient awareness reports to have no awareness, 87 to have possible awareness, and 65 to have definite awareness. The effect size favoured neither Bispectral Index monitoring nor standard clinical and electronic monitoring, with little precision in the OR estimate for the combination of definite and possible awareness (OR 0.96, 95% CI 0.35 to 2.65). The effect size favoured Bispectral Index monitoring for definite awareness, but with little precision in the OR estimate (OR 0.60, 95% CI 0.13 to 2.75).We performed three smaller meta-analyses of anaesthetic drugs. There were nine studies with 1290 participants. Wakefulness was reduced by ketamine and etomidate compared to thiopental. Wakefulness was more frequent than awareness. Benzodiazepines reduces awareness compared to thiopental, ketamine, and placebo., Also, higher doses of inhaled anaesthetics versus lower doses reduced the risk of awareness.We graded the quality of the evidence as low or very low in the 'Summary of findings' tables for the five comparisons.Most of the secondary outcomes in this review were not reported in the included RCTs.

AUTHORS' CONCLUSIONS

Anaesthetic depth monitors may have similar effects to standard clinical and electrical monitoring on the risk of awareness during surgery. In older studies comparing anaesthetics in a smaller portion of the patient sample, wakefulness occurred more frequently than awareness. Use of etomidate and ketamine lowered the risk of wakefulness compared to thiopental. Benzodiazepines compared to thiopental and ketamine, or higher doses of inhaled anaesthetics versus lower doses, reduced the risk of awareness.

Deep sedation in natural orifice transluminal endoscopic surgery (NOTES): a comparative study with dogs

BACKGROUND

Natural orifice transluminal endoscopic surgery (NOTES) has been mostly performed with the animal under general and inhalational anesthesia (IA-NOTES). To date, NOTES using propofol sedation (PS-NOTES) has not been investigated. This study aimed to assess the feasibility and safety of PS-NOTES for transgastric oophorectomy with carbon dioxide insufflation and to compare its success rates with those of conventional IA-NOTES.

METHODS

In this prospective randomized study, NOTES oophorectomy was performed for 19 female dogs randomized to two conditions: PS (study group) and IA (control group). Sedation success rates (ability to visualize and resect ovaries without converting to IA), operative success rates (ability to resect and retrieve both ovaries in full using only NOTES), and vital parameters including hemodynamic and respiratory changes were documented.

RESULTS

In the PS-NOTES group (n = 9), the sedation success rate was 100 %. The operative success rate was 67 % (6 of 9 animals) compared with 80 % (8 of 10 animals) in the IA-NOTES group. No purposeful movement occurred during surgical manipulation and no respiratory or cardiovascular complications in occurred the PS group. Heart rate (HR) and end-tidal carbon dioxide (ETCO(2)) were significantly higher in the PS group than in the IA group. Blood pressure (BP) was significantly higher in the PS group only during the middle part of the procedure. Only mild respiratory depression was noted in the PS group, as indicated by elevated but acceptable ETCO(2). Elevations in BP and HR are thought to be related to elevated CO(2) but did not appear to have an adverse impact on the course of the procedure. Recovery was uneventful for all the animals.

CONCLUSION

The use of PS-NOTES appears to be feasible, resulting in outcomes comparable with those for IA in dogs. Further studies are needed to determine the applicability of this concept in human NOTES.

Propofol vs isoflurane anesthesia-incidence of PONV in patients at maxillofacial surgery

PURPOSE

Prophylaxis of PONV (postoperative nausea and vomiting) is important for maxillofacial surgery. Vomiting is particularly unpleasant for the patient and undesirable as it may be detrimental to the operative area. The aim of this study is to compare the incidence of PONV after propofol with that after isoflurane anesthesia.

MATERIALS AND METHODS

84 patients age 15-50, ASA I-II, undergoing maxillofacial surgery were randomly allocated in two groups. Group P n=42 -using TIVA (Total Intravenous Anesthesia) with propofol and Group I n=42- using isoflurane anesthesia. The incidence and severity of PONV was evaluated for 24 hours postoperatively based on scoring system: 0=no emetic symptoms, 1=nausea, 2=vomiting. Whereas the severity of nausea was assessed using a four-point Likert scale, with 0=none, 1=mild, 2=moderate, 3=severe.

RESULTS

There were no significant differences between the groups with respect to demographic data and duration of anesthesia. The incidence of nausea (2-3 Likert scale) in the propofol group was 11.9% compared to the isoflurane group 38.1% during early post-operative period (0-6 hrs) (p=0.011), whereas during late post-operative period 7.1% in group P compared with 11.9% in group I (p=0.712).Incidence of vomiting in early post-operative period in-group P was 4.8%, whereas in-group I 11.9% (p=0.432). In late postoperative period in-group P no patient suffered from vomiting or retching, whereas in-group I 4.8% (p=0.494).

CONCLUSIONS

TIVA with propofol reduces the postoperative incidence of nausea and vomiting after maxillofacial surgery, compared with isoflurane anesthesia, and also reduces requirements of antiemetic medications.

Comparison of recovery profile after ambulatory anesthesia with propofol, isoflurane, sevoflurane and desflurane: a systematic review

In this systematic review we focused on postoperative recovery and complications using four different anesthetic techniques. The database MEDLINE was searched via PubMed (1966 to June 2002) using the search words "anesthesia" and with ambulatory surgical procedures limited to randomized controlled trials in adults (>19 yr), in the English language, and in humans. A second search strategy was used combining two of the words "propofol," "isoflurane," "sevoflurane," or "desflurane". Screening and data extraction produced 58 articles that were included in the final meta-analysis. No differences were found between propofol and isoflurane in early recovery. However, early recovery was faster with desflurane compared with propofol and isoflurane and with sevoflurane compared with isoflurane. A minor difference was found in home readiness between sevoflurane and isoflurane (5 min) but not among the other anesthetics. Nausea, vomiting, headache, and postdischarge nausea and vomiting incidence were in favor of propofol compared with isoflurane (P < 0.05). A larger number of patients in the inhaled anesthesia groups required antiemetics compared with the propofol group. We conclude that the differences in early recovery times among the different anesthetics were small and in favor of the inhaled anesthetics. The incidence of side effects, specifically postoperative nausea and vomiting, was less frequent with propofol.

IMPLICATIONS

A systematic analysis of the literature comparing postoperative recovery after propofol, isoflurane, desflurane, and sevoflurane-based anesthesia in adults demonstrated that early recovery was faster in the desflurane and sevoflurane groups. The incidence of nausea and vomiting were less frequent with propofol.

Cricoid yoke: the effect of surface area and applied force on discomfort experienced by conscious volunteers

BACKGROUND AND OBJECTIVE

The application of cricoid force is central to techniques that reduce the risk of gastric regurgitation and the subsequent pulmonary aspiration associated with obstetric and emergency anaesthesia. The discomfort associated with cricoid force in awake preoperative patients increases the incidence of coughing, struggling and pain during induction of anaesthesia. This study determined if increasing the surface area of a cricoid yoke reduced the associated discomfort in volunteers.

METHODS

Fifty volunteers participated in a randomized single-blinded study. The cricoid yoke was positioned using standard anatomical landmarks and forces of 10, 20, 30 and 40 N were applied in a random order for 20s, using two different yoke attachments with surface areas of 3 and 10 cm2. A rest of 30s was allowed between the application of forces. Discomfort was graded by volunteers on a scale from 0 to 10 (0: no discomfort; 10: worse discomfort imaginable). A score of 10 was allocated if the volunteers could not tolerate the applied force for 20s.

RESULTS

Median scores for the small yoke were always higher than those for the large yoke at each force. There were significant differences between the scores for the small and large yokes at 10 and 20 N (P < 0.001) and 30 N (P = 0.0233), but there was no significant difference at 40 N.

CONCLUSIONS

The larger yoke was tolerated better by volunteers when clinically relevant cricoid forces were applied.

Tracheal intubation without muscle relaxants: remifentanil or alfentanil in combination with propofol

BACKGROUND AND OBJECTIVE

In some situations, the use of muscle relaxants (neuromuscular blocking drugs) are undesirable or contraindicated. We compared intubating conditions without muscle relaxants in premedicated patients receiving either alfentanil 40 microg kg(-1) or remifentanil 2, 3 or 4 microg kg(-1) followed by propofol 2 mg kg(-1).

METHODS

In a randomized, double-blind study, 80 healthy patients were assigned to one of four groups (n = 20). After intravenous atropine, alfentanil 40 microg kg(-1) or remifentanil 2, 3 or 4 microg kg(-1) were injected over 90 s followed by propofol 2 mg kg(-1). Ninety seconds after administration of the propofol, laryngoscopy and tracheal intubation were attempted. Intubating conditions were assessed as excellent, good or poor on the basis of ease of lung ventilation, jaw relaxation, laryngoscopy, position of the vocal cords, and patient response to intubation and slow inflation of the endotracheal tube cuff.

RESULTS

Seven patients who received remifentanil 2 microg kg(-1) and one patient who received remifentanil 3 microg kg(-1) could not be intubated at the first attempts. Excellent intubating conditions (jaw relaxed, vocal cords open and no movement in response to tracheal intubation and cuff inflation) were observed in those who received either alfentanil 40 microg kg(-1) (45% of patients) or remifentanil in doses of 2 microg kg(-1) (20%), 3 microg kg(-1) (75%) or 4 microg kg(-1) (95%). Overall, intubating conditions were significantly better (P < 0.05), and the number of patients showing excellent conditions were significantly higher (P < 0.05) in patients who received remifentanil 4 microg kg(-1) compared with those who received alfentanil 40 microg kg(-1) or remifentanil 2 microg kg(-1). No patient needed treatment for hypotension or bradycardia.

CONCLUSIONS

Remifentanil 4 microg kg(-1) and propofol 2 mg kg(-1) administered in sequence intravenously provided good or excellent conditions for tracheal intubation in all patients without the use of muscle relaxants.

Stability of the LMA-ProSeal and standard laryngeal mask airway in different head and neck positions: a randomized crossover study

BACKGROUND AND OBJECTIVE

The LMA-ProSeal laryngeal mask airway is a new laryngeal mask airway with a modified cuff and drainage tube. We compared oropharyngeal leak pressure, intracuff pressure and anatomical position (assessed fibreoptically) for the Size 5 LMA-ProSeal laryngeal mask airway and the classic laryngeal mask airway in different head-neck positions and using different intracuff inflation volumes.

METHODS

Thirty paralysed anaesthetized adult male patients were studied. The LMA-ProSeal laryngeal mask airway and the classic laryngeal mask airway were inserted into each patient in random order. The oropharyngeal leak pressure, intracuff pressure, and anatomical position of the airway tube and drainage tube (LMA-ProSeal laryngeal mask airway only) were documented in four head and neck positions (neutral first, then flexion, extension and rotation in random order), and at 0-40 mL cuff volumes in the neutral position in 10 mL increments.

RESULTS

Compared with the neutral position, the oropharyngeal leak pressure for both the LMA-ProSeal laryngeal mask airway and the classic laryngeal mask airway was higher in flexion and rotation (all P < or = 0.02), but lower in extension (all P < or = 0.01). Changes in head-neck position did not alter the anatomical position of the airway tube or the drainage tube. The oropharyngeal leak pressure was always higher for the LMA-ProSeal laryngeal mask airway (all P < or = 0.005) and anatomical position better for the classic laryngeal mask airway (all P < or = 0.04).

CONCLUSIONS

The anatomical position of the LMA-ProSeal and the classic laryngeal mask airway is stable in different head-neck positions, but head-neck flexion and rotation are associated with an increase, and head-neck extension a decrease, in oropharyngeal leak pressure and intracuff pressure. The Size 5 LMA-ProSeal laryngeal mask airway is capable of forming a more effective seal than the Size 5 classic laryngeal mask airway in males.

Breathing pattern and workload during automatic tube compensation, pressure support and T-piece trials in weaning patients

BACKGROUND AND OBJECTIVE

Automatic tube compensation has been designed as a new ventilatory mode to compensate for the non-linear resistance of the endotracheal tube. The study investigated the effects of automatic tube compensation compared with breathing through a T-piece or pressure support during a trial of spontaneous breathing used for weaning patients from mechanical ventilation of the lungs.

METHODS

Twelve patients were studied who were ready for weaning after prolonged mechanical ventilation (10.2 +/- 8.4 days) due to acute respiratory failure. Patients with chronic obstructive pulmonary disease were excluded. Thirty minutes of automatic tube compensation were compared with 30 min periods of 7 cmH2O pressure support and T-piece breathing. Breathing patterns and workload indices were measured at the end of each study period.

RESULTS

During T-piece breathing, the peak inspiratory flow rate (0.65 +/- 0.20 L s(-1)) and minute ventilation (8.9 +/- 2.7L min(-1)) were lower than during either pressure support (peak inspiratory flow rate 0.81 +/- 0.25 L s(-1) minute ventilation 10.2 +/- 2.3 L min(-1), respectively) or automatic tube compensation (peak inspiratory flow rate 0.75 +/- 0.26L s(-1); minute ventilation 10.8 +/- 2.7 L min(-1)). The pressure-time product as well as patients' work of breathing were comparable during automatic tube compensation (pressure-time product 214.5 +/- 104.6 cmH2O s(-1) min(-1), patient work of breathing 1.1 +/- 0.4 J L(-1)) and T-piece breathing (pressure-time product 208.3 +/- 121.6 cmH2O s(-1) min(-1), patient work of breathing 1.1 +/- 0.4 J L(-1)), whereas pressure support resulted in a significant decrease in workload indices (pressure-time product 121.2 +/- 64.1 cmH2O s(-1) min(-1), patient work of breathing 0.7 +/- 0.4 J L(-1)).

CONCLUSIONS

In weaning from mechanical lung ventilation, patients' work of breathing during spontaneous breathing trials is clearly reduced by the application of pressure support 7 cmH2O, whereas the workload during automatic tube compensation corresponded closely to the values during trials of breathing through a T-piece.

Anaesthetic agents in adult day case surgery

This study reports a review of all comparative published studies of adult day case anaesthesia in the English language up to December 2000. Ten databases were searched using appropriate keywords and data were extracted in a standardized fashion. One hundred-and-one published studies were examined. Recovery measurements were grouped as early, intermediate, late, psychomotor and adverse effects. With respect to induction of anaesthesia, propofol was superior to methohexital, etomidate and thiopental, but equal to sevoflurane and desflurane. Desflurane and sevoflurane were both superior to thiopental. There was no detectable difference between sevoflurane and isoflurane. With respect to the maintenance of anaesthesia, isoflurane and halothane were the worst. There were no significant differences between propofol, desflurane, sevoflurane and enflurane. Propofol is the induction agent of choice in day case patients. The use of a propofol infusion and avoidance of nitrous oxide may help to reduce postoperative nausea and vomiting.

Prediction of difficult tracheal intubation

BACKGROUND AND OBJECTIVE

Preoperative bedside screening tests for difficult tracheal intubation may be neither sensitive nor specific enough for clinical use. The aim was to investigate if a combination of the Mallampati classification of the oropharyngeal view with either the thyromental or sternomental distance measurement improved the predictive value.

METHODS

A total of 212 (109 male, 103 female) non-obstetric surgical patients, aged >18 yr, undergoing elective surgical procedures requiring tracheal intubation were assessed preoperatively with respect to the oropharyngeal (modified Mallampati) classification, thyromental and sternomental distances. An experienced anaesthetist, blinded to the preoperative airway assessment, performed laryngoscopy and graded the view according to Cormack and Lehane's classification.

RESULTS

Twenty tracheal intubations (9%) were difficult as defined by a Cormack and Lehane Grade 3 or 4, or the requirement for a bougie in patients with Cormack and Lehane Grade 2. Used alone, the Mallampati oropharyngeal view, and thyromental and sternomental distances were associated with poor sensitivity, specificity and positive predictive values. Combining the Mallampati Class III or IV with either a thyromental distance <6.5cm or a sternomental distance <12.5cm decreased the sensitivity (from 40 to 25 and 20%, respectively), but maintained a negative predictive value of 93%. The specificity and positive predictive values increased from 89 and 27% respectively for Mallampati alone to 100%.

CONCLUSIONS

The findings suggest that the Mallampati classification, in conjunction with measurement of the thyromental and sternomental distances, may be a useful routine screening test for preoperative prediction of difficult tracheal intubation.

Remifentanil versus alfentanil in total intravenous anaesthesia for day case surgery

BACKGROUND AND OBJECTIVE

We assessed the intraoperative haemodynamic responses and recovery profiles of total intravenous anaesthesia with remifentanil and alfentanil for outpatient surgery.

METHODS

Patients in Group 1 (n = 20) received alfentanil 20 microg kg(-1) followed by 2 microg kg(-1) min(-1) intravenously; patients in Group 2 (n = 20) received remifentanil 1 microg kg(-1) followed by 0.5 microg kg(-1) min(-1) intravenously. Both groups then received propofol 2 mg kg(-1) followed by 9 mg kg(-1) h(-1) intravenously. Five minutes after skin incision, infusion rates were decreased, and at the end of surgery, all infusions were discontinued. Early recovery was assessed by the Aldrete score, whereas intermediate recovery was assessed with the postanaesthetic discharge scoring system (PADS).

RESULTS

Perioperative arterial pressure was similar in both groups; heart rate was lower in Group 2 (P < 0.05). The times to spontaneous and adequate respiration, response to verbal commands, extubation and times for Aldrete score > or = 9 were shorter in Group 2 patients (P < 0.05). Pain scores were higher in Group 2 patients (P < 0.05). Overall times for postanaesthetic discharge scores > or = 9 were similar.

CONCLUSIONS

Early recovery of patients after day surgery is significantly shorter after total intravenous anaesthesia with remifentanil compared with that with alfentanil but postoperative pain management must be planned ahead.

Effects of different doses of oral ketamine for premedication of children

BACKGROUND AND OBJECTIVE

A need exists for a safe and effective oral preanaesthetic medication for use in children undergoing elective surgery. The study sought to define the dose of oral ketamine that would facilitate induction of anaesthesia without causing significant side-effects.

METHODS

We studied 80 children undergoing elective surgery under general anaesthesia who received oral ketamine 4, 6 or 8 mg kg(-1) in a prospective, randomized, double-blind placebo controlled study. We compared the reaction to separation from parents, transport to the operating room, the response to intravenous cannula insertion and application of an anaesthetic facemask, the induction of anaesthesia and recovery from anaesthesia.

RESULTS

In the group receiving ketamine 8 mg kg(-1), the children were significantly calmer than those of the other groups, and anaesthesia induction was more comfortable. Recovery from anaesthesia was longer in the group receiving ketamine 8 mg kg(-1) compared with the other groups, but no differences between the groups were observed after 2 h in the recovery room.

CONCLUSIONS

It is concluded that oral ketamine 8 mg kg(-1) is an effective oral premedication in inpatient children undergoing elective surgery.

Trendelenburg positioning after cardiac surgery: effects on intrathoracic blood volume index and cardiac performance

BACKGROUND AND OBJECTIVE

The efficacy of the Trendelenburg position, a common first step to treat suspected hypovolaemia, remains controversial. We evaluated its haemodynamic effects on cardiac preload and performance in patients after cardiac surgery.

METHODS

Twelve patients undergoing mechanical ventilation of the lungs who demonstrated left ventricular 'kissing papillary muscles' by transoesophageal echocardiography, thus suggesting hypovolaemia, were positioned 30 degrees head down for 15 min immediately after cardiac surgery. Cardiac output by thermodilution, central venous pressure, pulmonary artery occlusion pressure, left ventricular end-diastolic area by transoesophageal echocardiography and intrathoracic blood volume by thermo- and dye dilution were determined before, during and after this Trendelenburg manoeuvre.

RESULTS

Trendelenburg's manoeuvre was associated with increases in central venous pressure (9 +/- 2 to 12 +/- 3 mmHg) and pulmonary artery occlusion pressure (8 +/- 2 to 11 +/- 3 mmHg). The intrathoracic blood volume index increased slightly (dye dilution from 836 +/- 129 to 872 +/- 112 mL m(-2); thermodilution from 823 +/- 129 to 850 +/- 131 mL m(-2)) as did the left ventricular end-diastolic area index (7.5 +/- 2.1 to 8.1 +/- 1.7 cm2 m(-2)), whereas mean arterial pressure and the cardiac index did not change significantly. After supine repositioning, the cardiac index decreased significantly below baseline (3.0 +/- 0.6 versus 3.5 +/- 0.8 L min(-1) m(-2)) as did mean arterial pressure (76 +/- 12 versus 85 +/- 11 mmHg), central venous pressure (8 +/- 2 mmHg) and pulmonary artery occlusion pressure (6 +/- 4 mmHg). The intrathoracic blood volume index and left ventricular end-diastolic area index did not differ significantly from baseline.

CONCLUSIONS

Trendelenburg's manoeuvre caused only a slight increase of preload volume, despite marked increases in cardiac-filling pressures, without significantly improving cardiac performance.

Anaesthetic and haemodynamic effects of continuous spinal versus continuous epidural anaesthesia with prilocaine

BACKGROUND AND OBJECTIVE

To compare, using prilocaine, the effects of continuous spinal anaesthesia (CSA) and continuous epidural anaesthesia (CEA) on haemodynamic stability as well as the quality of anaesthesia and recovery in patients undergoing transurethral resection of the prostate gland.

METHODS

Thirty patients (>60 yr) were randomized into two groups. Prilocaine, 2% 40 mg, was given to patients in the CSA group, and prilocaine 1% 150mg was given to patients in the CEA group. Incremental doses were given if the level of sensory block was lower than T10 or if needed during surgery.

RESULTS

There was a significant decrease in mean arterial pressure in Group CEA compared with Group CSA (P < 0.01). The decrease in heart rate in Group CSA occurred 10 min after the first local anaesthetic administration and continued through the operation (P < 0.05). The level of sensory anaesthesia was similar in both groups. The times to reach the level of T10 and the upper level of sensory blockade (Tmax) were 18.0 +/- 4.7 and 25.3 +/- 7.0 min in Groups CSA and CEA, respectively, and were significantly longer in Group CEA. The duration of anaesthesia was 76.8 +/- 4min and was shorter in Group CSA (P < 0.01).

CONCLUSIONS

Spinal or epidural anaesthesia administered continuously was reliable in elderly patients undergoing transurethral resection of the prostate. Continuous spinal anaesthesia had a more rapid onset of action, produced more effective sensory and motor blockade and had a shorter recovery period. Prilocaine appeared to be a safe local anaesthetic for use with either continuous spinal anaesthesia or continuous epidural anaesthesia.

Cortical activity assessed by Narcotrend in relation to haemodynamic responses to tracheal intubation at different stages of cortical suppression and reflex control

BACKGROUND AND OBJECTIVE

Many anaesthesiologists still interpret haemodynamic responses as signs of insufficient cortical suppression. The aim was to illustrate how haemodynamics may only poorly reflect the level of cortical suppression and that electroencephalographic monitoring could indicate different relationships between cortical effects and haemodynamics.

METHODS

Anaesthesia was induced with thiopental (7 mg kg(-1)), and fentanyl (2 microg kg(-1)) with succinylcholine (1.5 mg kg(-1)) for neuromuscular blockade in the 11 patients of Group 1. In Group 2 (n = 15), thiopental (7 mg kg(-1)) and succinylcholine (1.5 mg kg(-1)) were given. In Group 3, the patients (n = 13) received thiopental (7 mg kg(-1)), fentanyl (2 microg kg(-1)) and cisatracurium (0.1 mg kg(-1)), and they were intubated 3 min later than the patients in Groups 1 and 2. We determined conventional electroencephalographic (EEG) variables and classified 14 EEG stages in real-time ranging from A (= 1), indicating full wakefulness, to F1 (= 14), at profound cortical suppression.

RESULTS

All groups had profound cortical suppression 45 s after thiopental administration, which rapidly decreased (EEG stage, 11 (6-13) versus 7 (2-13) at 4 min, P < 0.0001). Decreasing EEG stages were associated with increasing SEF 95, relative alpha and beta power and decreasing relative delta power. During tracheal intubation, profound cortical suppression remained unchanged in Groups 1 and 2. In Group 3, cortical suppression had decreased before laryngoscopy (P < 0.005). In Group 2, 11 patients had heart rate responses to tracheal intubation, whereas only two responded in Group 1 (P = 0.015) and three in Group 3 (P = 0.02). Thirteen patients in Group 2 had arterial pressure responses, and five in Group 1 (P = 0.038). Circulatory responses did not differ between Groups 1 and 3.

CONCLUSIONS

Electroencephalographic monitoring was suitable to indicate in real-time that haemodynamics only poorly reflect rapidly changing levels of cortical suppression, and how haemodynamics and cortical activity depend on the applied combination of hypnotic and analgesic drugs during anaesthesia induction with thiopental.

Increasing the injection volume by dilution improves the onset of motor blockade, but not sensory blockade of ropivacaine for brachial plexus block

BACKGROUND AND OBJECTIVE

Ropivacaine used for axillary plexus block provides effective motor and sensory blockade. Varying clinical dosage recommendations exist. Increasing the dosage by increasing the concentration showed no improvement in onset. We compared the behaviour of a constant dose of ropivacaine 150 mg diluted in a 30, 40 or 60 mL injection volume for axillary (brachial) plexus block.

METHODS

A prospective, randomized, observer-blinded study on patients undergoing elective hand surgery was conducted in a community hospital. Three groups of patients with a constant dose of ropivacaine 150 mg, diluted in 30,40 or 60 mL NaCl 0.9%, for axillary plexus blockade were compared for onset times of motor and sensory block onset by assessing muscle strength, two-point discrimination and constant-touch sensation.

RESULTS

Increasing the injection volume of ropivacaine 150 mg to 60 mL led to a faster onset of motor block, but not of sensory block, in axillary plexus block, compared with 30 or 40 mL volumes of injection.

CONCLUSIONS

The data show that the onset of motor, but not of sensory block, is accelerated by increasing the injection volume to 60 mL using ropivacaine 150 mg for axillary plexus block. This may be useful for a more rapid determination of whether the brachial plexus block is effective. However, when performing surgery in the area of the block, sensory block onset seems more important.

Dolasetron, but not metoclopramide prevents nausea and vomiting in patients undergoing laparoscopic cholecystectomy

PURPOSE

Postoperative nausea and vomiting (PONV) is one of the most frequent complications of general anesthesia. The aim of the study was to compare the antiemetic efficacy of dolasetron and metoclopramide after inhalational or i.v. anesthesia (IVA).

METHODS

In a randomized, placebo-controlled, double-blinded trial we evaluated the efficacy of 12.5 mg dolasetron i.v. and 20 mg metoclopramide (MCP) i.v. in preventing PONV in 387 patients (ASA I-III) undergoing laparoscopic cholecystectomy. Patients were allocated randomly to one of three main groups: Group D (n = 129) received 12.5 mg dolasetron i.v., Group MCP (n = 129) 20 mg MCP i.v., and Group C (n = 129) saline as placebo i.v. Using a multifactorial study design, one third of each main group (n = 43) was further randomized to receive either general anesthesia with desflurane, isoflurane or IVA with propofol and remifentanil. PONV, postoperative piritramide and droperidol consumption were documented.

RESULTS

Independent from the anesthesia regimen chosen, dolasetron reduced PONV (19%) significantly compared to MCP (45%) and placebo (46%). Furthermore we could show a significant difference in the incidence of PONV between IVA (28%) and isoflurane (46%), but not in comparison to desflurane (36%). Patients receiving IVA had a higher postoperative piritramide consumption compared to the two other groups.

CONCLUSIONS

The results of our study suggest that dolasetron was more effective than MCP and placebo in preventing PONV. This action is independent of the anesthetic technique used.

A comparison of the effects of droperidol and the combination of droperidol and ondansetron on postoperative nausea and vomiting for patients undergoing laparoscopic cholecystectomy

STUDY OBJECTIVES

To compare the prophylactic antiemetic efficacy of the combination of ondansetron and droperidol with that of droperidol alone in patients undergoing elective laparoscopic cholecystectomy.

DESIGN

Randomized, double-blind controlled trial. University affiliated teaching hospital after induction of standardized general anesthesia.

PATIENTS

64 ASA physical status I or II patients aged 18 to 80 years, undergoing elective laparoscopic cholecystectomy.

INTERVENTION

Following induction of general anesthesia, patients received either droperidol 1.25 mg intravenously (IV; n = 30; Group D) or the combination of droperidol 1.25 mg IV and ondansetron 4 mg IV (n = 34; Group D+O).

MEASUREMENTS

Number and severity of nausea episodes, number of emetic episodes, total analgesic consumption, and rescue antiemetic administration were assessed at 1, 3, and 24 hours after admission to the recovery room. Data were analyzed using Fisher's Exact test and unpaired Student's t-test; a p-value <0.05 was considered significant.

RESULTS

The proportions of patients who experienced nausea (70% and 53% for D and D+O groups, respectively) and vomiting (30% and 19% for D and D+O groups, respectively) were similar in the two groups. The frequency of moderate and severe nausea (requiring administration of antiemetic) was less in group D + O (7%) compared with group D (19%; p < 0.05).

CONCLUSIONS

Patients who received the combination of droperidol and ondansetron experienced less severe nausea compared with patients who received droperidol alone.

Postoperative nausea and vomiting after total intravenous anesthesia with propofol and remifentanil or alfentanil: how important is the opioid?

STUDY OBJECTIVE

To compare the frequency and duration of postoperative nausea and vomiting (PONV) following total intravenous anesthesia (TIVA) with propofol and either remifentanil or alfentanil in outpatients undergoing arthroscopic surgery of the extremities.

DESIGN

Randomized, third-party blinded study.

SETTING

University medical center.

PATIENTS

100 ASA physical status I and II patients scheduled for arthroscopic surgery of the knee or shoulder.

INTERVENTIONS

The anesthesia regimen consisted of a bolus followed by continuous infusion of propofol (2 mg/kg followed by 120 microg/kg/min) and the opioid (remifentanil 0.5 microg/kg followed by 0.1 microg/kg/min or alfentanil 10 microg/kg followed by 0.25 microg/kg/min). Patients breathed 100% oxygen spontaneously through a Laryngeal Mask Airway (or an endotracheal tube when medically indicated). Opioids were titrated to maintain blood pressure and heart rate within 20% of baseline and a respiratory rate of 10 to 16 breaths/min. Propofol was titrated downward as low as possible without permitting patient movement.

MEASUREMENTS

Nausea was determined by an 11-point categorical scale and was recorded before surgery and multiple time points thereafter. The times of emetic episodes were recorded. Treatment of PONV was at the discretion of the postanesthesia care unit (PACU) nurses who were blinded to the identity of the opioid used.

MAIN RESULTS

Nausea scores were 0 at all time points in over 70% of the patients in each group. None of the 100 patients vomited while in the hospital, and only one patient required antiemetic therapy.

CONCLUSION

When propofol-based TIVA is used for arthroscopic surgery, short-acting opioids do not significantly affect the risk of PONV.

The effect of anaesthetic technique on postoperative nausea and vomiting after day-case gynaecological laparoscopy

Gynaecological surgery is of high emetogenic potential and both total intravenous anaesthesia (TIVA) and prophylactic antiemetic therapy may reduce the incidence of postoperative nausea and vomiting (PONV). We studied 144 patients scheduled for day-case gynaecological laparoscopy in a randomized trial comparing balanced inhalational anaesthesia and prophylactic dolasetron (group I+D) with propofol TIVA and dolasetron (group T+D) or TIVA alone (group T). The primary outcome of "complete response" (no vomiting, no treatment for PONV) was not significantly different among groups (34%, 51%, 32%; groups I+D vs T+D vs T, P=0.12). During the first hour after surgery, group I+D had nausea of greater severity (P<0.03). During hospital admission, group T had more vomiting (P<0.03). From discharge until 24 hours postoperatively, 55% of group I+D experience nausea and 38% vomited. The incidence and severity of nausea were significantly lower in the TIVA groups (P<0.04 and <0.05 respectively). There were no significant differences between groups T+D and T, although comparing all groups the complete response rate was highest and the post-discharge incidence and severity of nausea lowest in group T+D. In conclusion, propofol TIVA, with or without dolasetron, reduced postoperative nausea, but not perioperative vomiting or antiemetic requirement, when compared with inhalational anaesthesia plus dolasetron.

Total intravenous anesthesia for office-based laser facial resurfacing

BACKGROUND AND OBJECTIVE

Providing general anesthesia in an office-based setting can be time consuming, risky, and expensive. The purpose of this study was to describe a technique for total intravenous anesthesia (TIVA) technique that can be easily utilized by anesthesiologists in an office-based setting for laser facial resurfacing.

STUDY DESIGN/MATERIALS AND METHODS

Twenty-five American Society of Anesthesiologists (ASA) status classification I-II patients (22 females and three males) elected general anesthesia for laser facial resurfacing. All patients were premedicated with glycopyrrolate (0.2 mg IV). All anesthetics were administered by board-certified anesthesiologists, and ASA Standards for Anesthesia Monitoring were strictly followed. An induction dose of propofol (2. 0-2.5 mg/kg IV) was followed by laryngeal mask airway insertion (size 3 or 4). TIVA was maintained with a propofol infusion (50-250 mcg/kg/minute IV). Supplemental midazolam (2-4 mg IV), fentanyl (0. 05-0.20 mg IV), and oxygen (2-4 l/minute) were administered as needed. After completion of the laser procedure, TIVA was discontinued and the patients were allowed to awaken. Patients were discharged after achieving a Modified Post-Anesthetic Discharge Score of >/= 9.

RESULTS

Mean procedure duration was 48 +/- 21 minutes, and time to discharge after the procedure was 16 +/-6 minutes. All procedures and anesthetics were well tolerated and without complications. The only post-procedure complaint was an isolated, minor, and temporary sore throat.

CONCLUSIONS

TIVA is an excellent method for providing anesthesia for laser facial resurfacing in an office-based setting.