Intra-operative patient-controlled sedation and patient attitude to control. A crossover comparison of patient preference for patient-controlled propofol and propofol by continuous infusion

Comparison of Sedation Requirements for Cataract Surgery under Topical Anesthesia or Retrobulbar Block

PURPOSE

Topical anesthesia is increasingly being used for cataract surgery. However, it is believed that topical anesthesia causes an increased risk of intraoperative complications from unrestricted eye movement and insufficient pain control and more need for sedation. It is difficult to compare pain and anxiety experienced by individual patients; therefore, the authors used the method of patient-controlled sedation to determine whether there is a difference in sedation requirements under topical or retrobulbar anesthesia.

METHODS

In this prospective study, patients received either topical anesthesia (n=87) or retrobulbar block (n=104) and self-administered a mixture of midazolam (0.5 mg) and fentanyl (25 microg) in increments using a patient controlled analgesia infuser to achieve sedation. At the end of surgery, patients rated their pain on a 10-point numerical rating scale and their comfort on a 5-point scale. The number of demands and deliveries were noted from the patient controlled analgesia infuser display.

RESULTS

Pain scores were between 0 and 2 in 95.4% in the topical and in 94.2% in the retrobulbar group (p>0.05). Patient comfort was equal in both groups with 2.94+/-0.92 in the topical group and 2.92+/-0.99 in the retrobulbar group (p>0.05). Mean sedation requirements were similar in both groups: 26.4% of patients in the topical group and 19.2% in the retrobulbar group did not request any sedation (not significant, p>0.05).

CONCLUSIONS

Sedation requirements were similar for cataract surgery under topical and retrobulbar anesthesia.

Paravertebral blockade for day-case breast augmentation: a randomized clinical trial

BACKGROUND

Bilateral breast augmentation is an increasingly popular day-case procedure. Local infiltration with sedation is routinely used for its ease of application compared with the more complex and potentially riskier paravertebral blockade (PVB). We hypothesized that ropivacaine injected by experienced anesthesia providers into the paravertebral space as a PVB was more effective than ropivacaine injected by the operating surgeon (plastic surgeon) directly into the zone of surgical dissection.

METHODS

Forty female patients who were ASA physical status I or II and undergoing bilateral subpectoral cosmetic breast augmentation were recruited for participation in a prospective, randomized, single-blind study. Patients were randomized to 1 of 2 groups: ropivacaine via PVB, or surgical infiltration of ropivacaine. In both groups, the surgeon was asked to infiltrate the appropriate area with either saline (PVB group) or ropivacaine (local infiltration group). Both groups were sedated with propofol, titrated to effect. The plastic surgeon was blinded to the solution injected. Data collected included demographic characteristics, intraoperative cooperation scores, recovery room postoperative nausea and vomiting, analgesia use, and visual analog scale pain scores. All patients were asked to complete a preoperative anxiety and quality of recovery questionnaire and to record their pain scores and analgesia requirements on discharge. The outcome measures were (i) intraoperative patient cooperation as assessed by the plastic surgeon, (ii) propofol requirement, (iii) postoperative pain, and (iv) quality of recovery.

RESULTS

Forty patients completed the study. PVB improved intraoperative cooperation (significance of difference P < 0.001, WMWodds = 6.69 with 95% 1-sided confidence interval CI ≥2.85), reduced propofol requirement (significance of difference P = 0.005, WMWodds = 0.35, CI <0.69), and decreased average postoperative pain in the home environment (significance of difference P = 0.007, WMWodds = 0.38, CI <0.73). There were no PVB complications. Only patients from the surgical infiltration group required rescue analgesics (30%, significance of difference = 0.01).

CONCLUSIONS

In a limited number of patients, we found that PVB is superior to direct surgical infiltration of ropivacaine for bilateral breast augmentation in same-day surgery. These advantages need to be balanced against the potential risks of PVB, especially in an office setting.

[Sedation in surgical procedures using regional anesthesia in adult patients: results of a survey of Spanish anesthesiologists]

OBJECTIVE

To analyze the frequency and methods of sedation used in the context of regional anesthesia in adults by means of a national survey.

MATERIAL AND METHODS

We carried out a survey of participants at the courses of an anesthesiology training organization (Fundación Europea de Enseñanza en Anestesiología), held in Spain in 2006. The survey questionnaires asked about indications for sedation used during surgery under regional anesthesia as well as the form of administration, follow-up, and complications.

RESULTS

A total of 375 questionnaires were sent out and 185 responses were received (49.3%). Sedation is always used to accompany regional anesthesia by 69.2% of the respondents; 13.5% of them discuss the technique to be used with the patient and come to an agreement. The same type of sedation, regardless of the regional block performed, is used by 49.2% of respondents, and 64.3% use a scale to evaluate the level of sedation. The most favored sedation technique is continuous infusion, followed by target controlled infusion and boluses on demand. The most commonly used technique is sedation with bolus injections. Sixty percent use a single agent and 38.9% use combinations. The most commonly reported adverse effects are variability of patient response (53.5%) and respiratory complications (27%). In cases of ineffective regional blockade, 49.2% of those surveyed switch to general anesthesia.

CONCLUSIONS

Sedation is very often used to complement regional anesthesia in adult patients. Even though continuous infusion is considered to be the most appropriate form of administration, the most commonly used form is injection of boluses. Sedation with a single drug is used more frequently than drug combinations. Variability of individual response is the complication most commonly reported by the respondents.

Sedation and regional anaesthesia in the adult patient

This review discusses sedation for regional anaesthesia in the adult population. The first section deals with general aspects of sedation and shows that the majority of patients receiving sedation for regional anaesthesia are satisfied and would choose it again. Methods of assessing the level of sedation are discussed with emphasis on clinical measures. The pharmacology of the drugs involved in sedation is discussed, with propofol and remifentanil appearing to be the combination of choice for sedation in regional anaesthesia. The techniques for administering sedation are discussed and replacement of the traditional repeated boluses or continuous infusion with pharmacokinetic and patient-controlled systems is supported. Patient satisfaction studies suggest that patient-controlled systems are preferred.

Midazolam and pethidine versus propofol and fentanyl patient controlled sedation/analgesia for upper gastrointestinal tract ultrasound endoscopy: a prospective randomized controlled trial

BACKGROUND AND OBJECTIVES

The aim of this prospective, randomized study was to compare the standard regimen of midazolam and pethidine administered by the gastroenterologist versus patient controlled sedation with a propofol-fentanyl mixture during upper gastrointestinal tract endoscopic ultrasonography. Our primary end-points were patient satisfaction and patient cooperation assessed by endoscopist.

METHODS

Fifty-four consecutive patients, undergoing endoscopic ultrasonography, received sedation with midazolam and pethidine (Group M: n=27) or propofol and fentanyl (Group P: n=27). Group M: pethidine 0.7mg/kg midazolam 0.04mg/kg before examination; boluses of same drugs if the sedation was insufficient plus a sham patient controlled sedation analgesia; Group P: propofol 17mg plus fentanyl 15microg before examination and a patient controlled sedation analgesia pump containing 170mg propofol plus 150microg fentanyl injecting 0.5ml every time the patient pressed the button (no "lock out"). Boluses of 1ml of the same mixture if the sedation was insufficient.

RESULTS

Group M: mean dosage of pethidine and midazolam 88.6 and 5mg, respectively. Group P: mean dosage of propofol and fentanyl 119.7mg and 106microg, respectively. Both groups were similar for duration and difficulty of the procedure, the grade of sedation (Observer's Assessment of Alertness/Sedation Score) and judgement by endoscopist and patient about cooperation and satisfaction. The only difference between groups was about the extra boluses administered during the procedure.

CONCLUSION

This study demonstrated that a patient controlled sedation analgesia with propofol and fentanyl is an effective and safe technique for upper gastrointestinal tract endoscopic ultrasonography procedures and results in a high level of satisfaction both for patients and operator.

Comparison of a Bolus of Fentanyl With an Infusion of Alfentanil During Target-Controlled Propofol Infusion in Third Molar Extraction Under Conscious Sedation

PURPOSE

This study was designed to compare hemodynamic changes, respiratory depression, and patient satisfaction between a bolus of fentanyl and an infusion of alfentanil during target-controlled propofol infusion in third molar extraction under conscious sedation.

PATIENTS AND METHODS

Forty patients were randomly assigned to receive either a bolus of fentanyl (n = 24) or an infusion of alfentanil (n = 16) in combination with target-controlled propofol infusion. Hemodynamic changes, respiratory depression, sedation, and cooperation scores were recorded during surgery and patient satisfaction scores were assessed after surgery.

RESULTS

Changes in mean blood pressure, heart rate, or oxygen saturation within and between the groups were not significant throughout the procedure. There were no significant differences in sedation, cooperation, and patient satisfaction scores between the 2 groups.

CONCLUSION

Because there was no difference in hemodynamic variables and patient satisfaction scores between a bolus of fentanyl and an infusion of alfentanil during target-controlled propofol infusion, both combinations are suitable for conscious sedation in third molar extraction.

Effect-site targeted patient-controlled sedation with propofol: comparison with anaesthetist administration for colonoscopy

Patient-controlled sedation (PCS) allows patients to match their sedation requirement to perceived discomfort. The significant delay in onset of sedation may be overcome with effect-site steered target controlled infusion, but previously only trials in volunteers have been carried out. We therefore conducted a randomised, double-blind controlled trial comparing effect-site steered propofol PCS with anaesthetist-administered propofol sedation in 40 patients presenting for colonoscopy. The initial effect-site target in the PCS group was 0.8 microg.ml(-1), increment was 0.1 microg.ml(-1) and lockout was 3 min. Patient and endoscopist satisfaction and operating conditions were similar between the two groups. PCS patients were sedated more slowly (13 [7.1] vs. 3 [1.1] min; p < 0.0001) and less deeply (minimum BIS value: 71 [16] vs. 58 [15]; p = 0.13) than anaesthetist-administered propofol sedation patients. More of the latter patients were hypotensive, but all patients had similar recollection of events during the procedure and similar quality of recovery.

Recent developments in patient-controlled analgesia

Patient-controlled analgesia (PCA) has become the gold standard for acute pain management since it was first introduced 20 years ago, and its merits have been discussed in quite a large number of publications. This review summarizes the more recent developments, such as new application devices and strategies, including intranasal, spinal, and regional PCA; patient-controlled sedation; experience with children and elderly people; and some data from chronic pain situations. Analyzing PCA literature from 2001 onwards confirms the author's long belief that the PCA principle ("WYNIWYG": what you need is what you get) was the most important aspect of a patient-controlled strategy, more or less independent of the type of drug or machine. Discovering this principle has changed the understanding of pain and suffering.

Patient maintained propofol sedation for dental surgery

AIM

This study evaluated a system for patients to operate a target-controlled infusion (TCI) of propofol for sedation.

PARTICIPANTS

50 healthy adults, undergoing minor oral surgical procedures under local anaesthesia.

METHODS

Following instructions, patients were allowed to control their own sedation to comfortably undergo surgery.

OUTCOME MEASURES

Operating conditions, degree of sedation, vital signs and patients' assessment of the technique.

RESULTS

Operating conditions were described as good in 47 patients and fair in 3. Optimal sedation was provided at a median target blood concentration of 2 mcg/ml (range1-3mcg/ml). 30 were sedated moderately, 16 deeply and 4 mildly. None were oversedated. The vital signs were stable in all patients. 30% of patients had injection pain and 28% became talkative. Patient satisfaction was high with 86% feeling adequately relaxed and 92% willing to use it again. 14 patients had complete and 22 had partial amnesia for the procedure.

CONCLUSIONS

This technique combines the benefits of target-controlled infusion with patient-controlled feedback and produces safe dental sedation.

Patient-controlled sedation with propofol in minor oral surgery

PURPOSE

We sought to evaluate the benefits of patient-controlled sedation with propofol for minor oral surgery.

PATIENTS AND METHODS

After instructions were given on how to use the technique, 28 male and 24 female patients sedated themselves during minor oral surgery with titrating 18-mg bolus doses of propofol with a lockout period of 1 minute.

RESULTS

Surgery lasted from 5 to 29 minutes; 28 patients were moderately and 17 were deeply sedated. Seven patients were oversedated. All of those who were oversedated responded to commands within 1 minute of being unresponsive and continued to obtain increments of propofol. Vital signs were stable in all patients even during oversedation. Eighteen patients were talkative, and 17 complained of pain along the vein. Operating conditions were good in 38, fair in 12, and poor in 2. The majority, 48 patients, were relaxed, and 47 were willing to undergo the sedation technique again. Ten had total, 22 had partial, and 20 had no amnesia.

CONCLUSIONS

Relaxed patients, good operating conditions, and quick recovery of oversedated patients without unstable vital signs provide evidence that propofol has favorable pharmacokinetic and pharmacodynamic properties for patient-controlled sedation. This study also highlights the importance of close monitoring of patients during patient-controlled sedation.

Patient-controlled sedation using propofol for dressing changes in burn patients: a dose-finding study

The first change of dressings after skin grafting in burn patients is a source of great anxiety because of pain anticipation and the immediate and first confrontation with the result of skin grafting. We designed this dose-finding study to determine the feasibility and safety of patient-controlled sedation (PCS) using propofol during these procedures. Twenty patients were familiarized with the PCS and asked to use PCS whenever they felt uncomfortable or anxious. Analgesia was provided by a single bolus of morphine IV 15 min before the procedure according to their daily intake. The first 10 patients used a fixed bolus of propofol 0.3 mg/kg and a lockout of 5 min. The degree of sedation was measured using bispectral index (BIS) monitoring. Demands versus delivery of propofol boluses were recorded. Within 1 h after the procedure, pain intensity was evaluated and satisfaction scores obtained from patients and nurses performing the dressing changes. In the first 10 patients, there were no respiratory rates <10 breaths/min, systolic and diastolic blood pressure were within 25% of baseline values, and peripheral saturation stayed more than 94% with additional small flow oxygen via nasal insufflation. There were double the demands than actual deliveries of propofol boluses. The BIS did not show significant decreases of <80 in any patient reflecting an insufficient state of sedation. Because the interim analysis of the efficacy of the PCS setup showed an insufficient state of sedation, a different PCS setup was evaluated in a second group of 10 patients (an individualized propofol bolus, titrated to achieve a significant decrease of BIS or a sleepy state, and no lockout period). The second group of patients showed a more effective sedation, with respiratory and hemodynamic variables being not significantly different from the first group of patients. PCS with propofol is feasible in burn patients and can be used safely. To provide an optimal sedation, we suggest to initially titrate the bolus to achieve a significant decrease of BIS or a clinically effective state of sedation and to abolish the lockout interval.

A randomised crossover comparison of patient-controlled sedation and patient-maintained sedation using propofol

This randomised, crossover study compared patient-controlled sedation using boluses of propofol and patient-maintained sedation using a target-controlled infusion of propofol. Twenty-three patients aged 18-35 years having surgical removal of bilateral third molar teeth under local anaesthesia during two separate visits were studied. In the majority of patients, both techniques provided moderate sedation, good operating conditions, stable physiological parameters and a high degree of patient satisfaction. Two patients became over-sedated during patient-controlled sedation. The time taken for titration to adequate sedation was longer with patient-maintained sedation than with patient-controlled sedation [mean (SD) = 8.6 (3.7) min vs. 5.7 (3.1) min, p < 0.005]. The mean overall propofol consumption was similar with both techniques. The majority of patients preferred patient-maintained sedation to patient-controlled sedation, p < 0.05.

A comparison of target-controlled therapy with patient-controlled administration of propofol combined with midazolam for sedation during dental surgery

Forty anxious day case patients undergoing extraction of third molar teeth under local anaesthesia with sedation, were studied in a randomised double-blind controlled trial. A target-controlled infusion of propofol was compared with patient-controlled propofol for sedation, combined with a small dose of midazolam to improve amnesia. The objectives of the study were to measure the total dose of propofol used by the two groups and assess recovery and patient satisfaction. The mean dose of propofol used in the patient-controlled sedation group was significantly less than the target-controlled group (p < 0.00007). Five patients became over-sedated in the target-controlled group compared with none in the patient-controlled group. Only one of the three tests of performance showed that the target-controlled patients were more sedated. Patient satisfaction was high in both groups despite a greater recollection of events in the patient-controlled group.

A comparative study of sevoflurane sedation with nitrous oxide sedation for dental surgery

This study compares the use of inhalation sedation using sevoflurane (group S) with inhalation sedation using nitrous oxide (group N) in patients undergoing bilateral extraction of third molar teeth under local anaesthesia. The study was designed as a cross-over study. Seventeen ASA I, day surgery patients were studied. Patients were randomly allocated to receive either 8 l/min 50% nitrous oxide in oxygen (group N) or same flow of 1% sevoflurane (group S) for the first procedure. Each patient then had the alternate method of sedation for the second procedure. There were no significant differences between the methods in patient co-operation and surgeon's satisfaction with sedation. Psychomotor tests were comparable in both groups. The patients were significantly more sedated in the group S compared to group N (P=0.004). Significantly more patients complained of an unpleasant odour group S (P<0.01) but none withdrew from the study for this reason. No adverse cardiorespiratory effects resulted from sevoflurane or nitrous oxide sedation. Both methods gave good amnesia during the procedure. There was high acceptance of both methods and the patients rated the technique as equally satisfactory. We conclude that inhalation sedation with sevoflurane is a suitable alternative method to nitrous oxide sedation.

A comparison of patient-controlled sedation using either remifentanil or remifentanil-propofol for shock wave lithotripsy

Patient-controlled sedation (PCS) has been used for extracorporeal shock wave lithotripsy (SWL) because it allows for rapid individualized titration of anesthetics. Because of its sedating effects, the addition of propofol to remifentanil may improve patient tolerance of SWL with PCS. One hundred twenty patients were randomly assigned to receive remifentanil 10 microg or remifentanil 10 microg plus propofol 5 mg for PCS with zero-lockout interval. Nine patients in the Remifentanil group and three patients in the Remifentanil-Propofol group required additional sedatives to complete their SWL (P = 0.128). Compared with the Remifentanil group, the Remifentanil-Propofol group required less remifentanil, had a decreased incidence of postoperative nausea and vomiting, and had a better overall satisfaction level. However, they had an increased incidence of transient apnea and oxygen desaturation. The incidence of apnea was 15% in the Remifentanil group and 52% in the Remifentanil-Propofol group (P < 0.001). All patients were able to move themselves to the stretcher at the end of SWL, and median time to home discharge was <70 min in both groups. Both remifentanil and remifentanil-propofol were useful for PCS during SWL.

IMPLICATIONS

The addition of propofol to remifentanil improves patient satisfaction and decreases postoperative nausea and vomiting. However, it causes more respiratory depression than remifentanil alone. When remifentanil-propofol is used with patient-controlled sedation, appropriate monitoring and a minimum 1-2 min lockout interval is required.

Safer colonoscopy with patient-controlled analgesia and sedation with propofol and alfentanil

BACKGROUND

The aim of this study was to assess the efficacy of patient-controlled analgesia and sedation with propofol/alfentanil for colonoscopy compared with continuous drug infusion and conventional nurse-administered medication.

METHODS

One hundred fifty patients undergoing colonoscopy on an outpatient basis were randomly assigned to 1 of 3 medication regimens. To maintain blinding, all patients were connected to an infusion pump. Group I patients could self-administer boluses of 4.8 mg propofol and 125 microg alfentanil without restriction. Group II patients received a continuous infusion with 0.048 mg/kg propofol and 0.12 microg/kg alfentanil per minute. Group III patients received intravenous premedication with 0.035 mg/kg midazolam and 0.35 mg/kg meperidine.

RESULTS

There were no differences between the groups with respect to pain (visual analogue scale) and procedure time. Patient-controlled analgesia and sedation with propofol/alfentanil (group I) resulted in less of an increase in the transcutaneous partial pressure of carbon dioxide (p = 0.0004) during colonoscopy and less of a decrease in mean arterial blood pressure (p = 0.0021) during recovery, as well as more complete recovery (p = 0.0019) after 45 minutes compared with conventional administration of midazolam/meperidine. Furthermore, patient-controlled analgesia and sedation yielded a higher degree of patient satisfaction than continuous infusion of propofol/alfentanil (p = 0.0033) or nurse-administered midazolam/meperidine (p = 0.0094).

CONCLUSIONS

Patient-controlled administration of propofol and alfentanil for colonoscopy may provide a better margin of safety than conventional administration of midazolam and meperidine and results in a higher level of patient satisfaction and shorter recovery.

Safety of patient-maintained propofol sedation using a target-controlled system in healthy volunteers

We investigated the safety of a patient-maintained system that allows individuals to operate a target-controlled infusion of propofol to achieve sedation. Ten healthy volunteers were recruited and instructed to try to anaesthetize themselves with the system. A target-controlled infusion of propofol was set to deliver a target propofol concentration of 1 microgram ml-1, and the subjects allowed to increase the target in increments of 0.2 microgram ml-1 by pressing a control button twice in 1 s. There was a lockout time of 2 min and a maximum permitted target concentration of 3 micrograms ml-1. Heart rate and pulse oximetry oxygen saturation (SpO2) were monitored continuously, and non-invasive arterial pressure, ventilatory frequencies and sedation scores were measured every 5 min. Sedation was continued until the subject stopped pressing the button. A keyword was then read for the individual to remember and sedation discontinued. There were no instances of significant decrease of SpO2 or loss of airway control. Maximum target blood concentration of propofol recorded ranged from 1.4 to 3 micrograms ml-1. Two subjects became oversedated, one of whom was unrousable with loss of eyelash reflex. No subject could recall the keyword, although one recognized it from a list of 10 words. We conclude that the patient-maintained sedation system described could not be guaranteed to produce only conscious sedation in all patients, and that close clinical supervision by an anaesthetist would still be required for safe operation.

Sedation for vitreoretinal surgery: a comparison of anaesthetist-administered midazolam and patient-controlled sedation with propofol

Local anaesthesia is increasingly being used for vitreoretinal surgery, but the optimal technique for sedation remains unclear. Anaesthetist-administered midazolam, which is often used, was compared in this study to patient-controlled sedation with propofol in 43 patients undergoing 50 vitreoretinal procedures. A variety of patient, anaesthetist and surgical endpoints were measured. There were no significant outcome differences between the two agents except that midazolam produced more amnesia for the local anaesthetic eye block. However, several outcomes and the observations in patients who experienced both agents showed a trend in favour of propofol for intraoperative sedation. We conclude that both approaches are safe and that patient-controlled sedation with propofol is at least as satisfactory as anaesthetist-administered midazolam.

Two methods of administration of propofol for dental sedation

Propofol was used for intravenous sedation in a group of 19 healthy fit young patients undergoing third molar extractions. We compared two ways of giving the drug, patient-controlled and operator-controlled, in a crossover trial. There were no differences between the two methods. The psychomotor functions returned to normal by 60 min, there was a high incidence of partial or complete amnesia and both methods were acceptable to 18/19 patients. There were only minimal changes in the respiratory function, and oxygen saturation remained normal. The only problem noted was mild pain on injection in 4 patients.

Propofol sedation during awake craniotomy for seizures: patient-controlled administration versus neurolept analgesia

This prospective study evaluated the safety and efficacy of patient-controlled sedation (PCS) using propofol during awake seizure surgery performed under bupivacaine scalp blocks. Thirty-seven patients were randomized to receive either propofol PCS combined with a basal infusion of propofol (n = 20) or neurolept analgesia using an initial bolus dose of fentanyl and droperidol followed by a fentanyl infusion (n = 17). Both groups received supplemental fentanyl and dimenhydrinate for intraoperative pain and nausea, respectively. Comparisons were made between groups for sedation, memory, and cognitive function, patient satisfaction, and incidence of complications. Levels of intraoperative sedation and patient satisfaction were similar between groups. Memory and cognitive function were well preserved in both groups. The incidence of transient episodes of ventilatory rate depression (<8 bpm) was more frequent among the propofol patients (5 vs 0, P = 0.04), particularly after supplemental doses of opioid. Intraoperative seizures were more common among the neurolept patients (7 vs 0, P = 0.002). PCS using propofol represents an effective alternative to neurolept analgesia during awake seizure surgery performed in a monitored care environment.

Safe anesthetic management of patients undergoing a novel method of treating human hepatocellular cancer

STUDY OBJECTIVE

To evaluate the safety and efficacy of monitored anesthesia care (MAC) in patients who undergo a novel treatment for hepatocellular cancer in which procedure-related hemodynamic instability is problematic.

DESIGN

Nonrandomized open study.

SETTING

University cancer center operating room.

PATIENTS

Nine patients scheduled for hepatic arterial infusion of doxorubicin with complete hepatic venous isolation and extracorporeal chemofiltration (no more than 3 procedures per patient).

INTERVENTIONS

Hepatic venous isolation was achieved with a dual-balloon inferior vena cava catheter connected to an extracorporeal circuit containing chemofilters. Doxorubicin was infused through the hepatic artery and filtered from the venous blood, which was returned to the patient through an internal jugular venous catheter. Each patient received a bolus of propofol (200 micrograms/kg) and one of alfentanil (2 micrograms/kg) followed by simultaneous infusions of propofol and alfentanil for percutaneous placement of the catheters and operation of the extracorporeal circuit. Drug rates were varied to maintain a sedative-analgesic state of calm, comfort, minimal movement, and adequate respiratory function. Prior to circuit initiation, patients were preloaded with crystalloid. During circuit operation, hypotension was treated with intravenous (IV) phenylephrine and crystalloid.

MEASUREMENTS AND MAIN RESULTS

End-tidal CO2 (PETCO2), respiratory rate, oxygen saturation (SaO2), arterial blood pressure (BP), and heart rate (HR) were monitored. Systolic, diastolic, and mean arterial pressure (MAP), and HR were compared before, during, and after hepatic venous isolation and chemofiltration. Doses and infusion rates of propofol, alfentanil, and phenylephrine were recorded for each treatment. Hypotension occurred in 11 of 13 procedures when blood was directed through the chemofilters and was successfully treated with phenylephrine (dose range 40 to 5,733 micrograms) and crystalloid. Blood pressure returned to the baseline value on termination of the circuit. Throughout the sedation, patients were easily arousable, analgesia was adequate, and PETCO2 level of 38 +/- 4 mmHg and SaO2 greater than 94% were maintained. Mean doses and infusion rates of MAC drugs were, respectively: propofol, 261 +/- 88 mg and 23.7 +/- 3.6 micrograms/kg/min; alfentanil, 3,350 +/- 1,468 micrograms and 0.32 +/- 0.14 microgram/kg/min.

CONCLUSIONS

Patients undergoing this novel cancer treatment are safely and effectively managed by MAC achieved with simultaneous infusions of alfentanil and propofol. Procedure-associated hypotension is easily treated with IV phenylephrine and crystalloid.

Propofol patient-controlled sedation during hip or knee arthroplasty in elderly patients

PURPOSE

Little information is available regarding the use of patient-controlled sedation (PCS) among the elderly. This study evaluated the safety and efficacy of propofol PCS among elderly patients undergoing hip or knee arthroplasty.

METHODS

Forty patients, aged 65-78 yr, undergoing hip or knee arthroplasty under regional anaesthesia were randomized to receive propofol PCS (dose = 0.3 mg.kg-1, delay = three min; n = 20) or anaesthetist-administered midazolam-fentanyl sedation (n = 20). Sedation, anxiety and discomfort visual analogue scores (VAS) were measured, by an independent observer, preoperatively, immediately at the end of surgery and one hour following admission to the postanaesthetic care unit (PACU). Cognition was evaluated, using an abbreviated Mini Mental Status Examination, preoperatively and in the PACU. Patient satisfaction, based on VAS and a brief questionnaire, was measured in the PACU. The incidence of intraoperative complications was also compared.

RESULTS

Patient satisfaction was high in each group. Sedation and anxiety VAS were similar in each group. A high incidence of pain with drug injection was noted among patients receiving propofol (80%). Transient deeper levels of sedation (6 vs 1; P = 0.05) were observed more commonly in the propofol PCS group.

CONCLUSION

Propofol PCS provides effective sedation. Using a propofol dose of 0.3 mg.kg-1, transient episodes of deeper sedation were noted more frequently among patients receiving PCS. These episodes did not require intervention but, suggest that this propofol PCS dose approaches the limit of safety and should be further reduced for some elderly patients.

Patient-controlled propofol sedation for elderly patients: safety and patient attitude toward control

PURPOSE

Little information is available regarding the use of patient-controlled sedation (PCS) among elderly patients undergoing operative procedures under local or regional anaesthesia. This prospective, randomized study evaluated the safety of propofol PCS, and the attitude among elderly patients toward self-administration of sedation during cataract surgery.

METHODS

Prospective, randomized study conducted in a University affiliated, tertiary-care hospital. Fifty-five elderly patients (aged 65-79 yr) were randomized to receive propofol patient-controlled sedation (PCS) (n = 28) or no intraoperative sedation (n = 27) during cataract surgery performed under peribulbar block. The PCS parameters consisted of a lockout interval of three minutes and a PCS dose of 0.3 mg.kg-1. Study groups were compared with respect to sedation, anxiety and discomfort visual analogue scores (VAS), cognitive functioning, patient satisfaction and the incidence of intraoperative complications.

RESULTS

Patients in the PCS group administered a mean propofol dose of 65 +/- 49 mg during procedures with a mean duration of 46 min. The incidence of intraoperative complications and sedation, anxiety and discomfort VAS were similar between groups. Patient satisfaction with PCS was high. In the PCS group, 10 (35%) of the 28 patients did not use the device because they were comfortable and did not feel they needed sedation. Satisfaction was higher in the PCS group (P = 0.02), whether or not they used the PCS device, compared with patients who did not receive a PCS device.

CONCLUSIONS

Propofol PCS represents a safe sedation technique among elderly patients in a monitored care setting. Elderly patients appear to prefer the option of receiving some form of intraoperative sedation and respond favourably to the opportunity to control administration.

Monitored patient-controlled sedation: practical technique or academic research tool?

Monitored patient-controlled sedation (MPCS) is a technique that allows patients to administer intravenous sedatives, under the supervision of an anaesthetist, to achieve a level of conscious sedation that meets their individual requirements. Experience to date has shown that this technique is effective and highly acceptable to patients. Propofol is an appropriate choice of agent for MPCS. Criteria for such agents include short arm-brain circulation time, which results in a rapid and clearly defined onset of action. The MPCS technique offers a number of benefits to the patient and the theatre staff.

Propofol. An overview of its pharmacology and a review of its clinical efficacy in intensive care sedation

Propofol is a phenolic derivative that is structurally unrelated to other sedative hypnotic agents. It has been used extensively as an anaesthetic agent, particularly in procedures of short duration. More recently it has been investigated as a sedative in the intensive care unit (ICU) where it produces sedation and hypnosis in a dose-dependent manner. Propofol also provides control of stress responses and has anticonvulsant and amnesic properties. Importantly, its pharmacokinetic properties are characterised by a rapid onset and short duration of action. Noncomparative and comparative trials have evaluated the use of propofol for the sedation of mechanically ventilated patients in the ICU (postsurgical, general medical, trauma). Overall, propofol provides satisfactory sedation and is associated with good haemodynamic stability. It produces results similar to or better than those seen with midazolam or other comparator agents when the quality of sedation and/or the amount of time that patients were at adequate levels of sedation are measured. Patients sedated with propofol also tend to have a faster recovery (time to spontaneous ventilation or extubation) than patients sedated with midazolam. Although most studies did not measure time to discharge from the ICU, propofol tended to be superior to midazolam in this respect. In a few small trials in patients with head trauma or following neurosurgery, propofol was associated with adequate sedation and control of cerebral haemodynamics. The rapid recovery of patients after stopping propofol makes it an attractive option in the ICU, particularly for patients requiring only short term sedation. In short term sedation, propofol, despite its generally higher acquisition costs, has the potential to reduce overall medical costs if patients are able to be extubated and discharged from the ICU sooner. Because of the potential for hyperlipidaemia and the development of tolerance to its sedative effects, and because of the reduced need for rapid reversal of drug effects in long term sedation, the usefulness of propofol in long term situations is less well established. While experience with propofol for the sedation of patients in the ICU is extensive, there are still areas requiring further investigation. These include studies in children, trials examining cerebral and haemodynamic outcomes following long term administration and in patients with head trauma and, importantly, pharmacoeconomic investigations to determine those situations where propofol is cost effective. In the meantime, propofol is a well established treatment native to benzodiazepines and/or other hypnotics or analgesics when sedation of patients in the ICU is required. In particular, propofol possesses unique advantages over these agents in patients requiring only short term sedation.

New developments in patient-controlled postoperative analgesia

Patient-controlled analgesia (PCA) is a newer technique for pain management. Patients are allowed to self-administer small analgesic bolus doses into a running intravenous infusion, intramuscularly, subcutaneously or even into the epidural space. Demands are usually controlled by computer-driven infusion pumps, but can also be delivered by disposable devices. Clinical experience demonstrates that individual variability in pain sensitivity and analgesic needs are of utmost importance. In contrast to earlier expectations, opioid consumption is usually higher than with restrictive conventional dosing regimes, but without an increase in serious side effects. Patients' acceptance is generally enthusiastic because of the possibility of self-control. PCA has proved its importance for pain studies, e.g. for algesimetry, to determine predictors of postoperative pain, to describe drug interactions, to evaluate the concept of pre-emptive analgesia or for pharmacokinetic designs. It is concluded that PCA results have been urgently required in order to change the mind of physicians and nursing staff with respect to individual pain management strategies. Once this goal is achieved, PCA concepts should also be used for the improvement of more conventional techniques.