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Biomedical subjects

S A Schug

Publications and source records attributed to S A Schug.

At least 19 recordsLinked to original sources
PubMed2006

Skin conductance monitoring compared with Bispectral Index to assess emergence from total i.v. anaesthesia using propofol and remifentanil.

BACKGROUND: Arousal after sevoflurane anaesthesia has been detectable by monitoring changes in skin conductance (SC) with similar accuracy as monitoring Bispectral Index (BIS). As SC monitoring detects changes in sympathetic tone, the measurements might be confounded by the sympatholytic properties of propofol, a component of total i.v. anaesthesia (TIVA). Therefore in this study, monitoring of SC during emergence from TIVA was compared with the monitoring of BIS. METHODS: Twenty-five patients undergoing plastic surgery were investigated. The number of fluctuations of SC per second (NFSC), BIS and haemodynamic variables [systolic blood pressure (SBP) and heart rate (HR)] were recorded simultaneously. The performance of the monitoring devices in distinguishing between the clinical states 'steady-state anaesthesia', 'first clinical reaction' and 'extubation' were compared using the method of prediction probability (Pk) calculation. RESULTS: BIS((R)) showed the best performance in distinguishing between 'steady-state anaesthesia' and 'first reaction' (Pk BIS 0.99 vs NFSC 0.80; P<0.01), and 'steady-state anaesthesia' and 'extubation' (Pk BIS) 1.00 vs NFSC 0.91; P<0.05); the time from first change of BIS or NFSC to a first clinical reaction was significantly longer for NFSC (median BIS 135 s vs NFSC 191 s; P<0.05). BIS and NFSC performed better in distinguishing between the investigated clinical states than SBP and HR. CONCLUSIONS: In this study, BIS was found to predict arousal with a higher probability but slower response times than NFSC in patients waking after TIVA.

Adult↗
PubMed2006

Monitoring of skin conductance to assess postoperative pain intensity.

BACKGROUND: Pain is known to alter the electrogalvanic properties of the skin. The aim of this pilot study was to investigate the influence of postoperative pain on skin conductance (SC) readings. METHODS: After obtaining ethical approval and written informed consent, 25 postoperative patients were asked to quantify their level of pain on a numeric rating scale (NRS, 0-10) at different time points in the recovery room. As a parameter of SC, the number of fluctuations within the mean SC per second (NFSC) was recorded. Simultaneously, the NRS was obtained from patients by a different observer who was blinded to the NFSC values. RESULTS: Data from 110 readings of 25 patients (14 female, 11 male; 21-67 yr) were included. NFSC showed a significant correlation with the NRS (r=0.625; P<0.01), whereas heart rate and blood pressure showed no or very weak correlation with the NRS. NFSC was significantly different between patients with no (NRS=0), mild (NRS=1-3), moderate (NRS=4-5) and severe (NRS=6-10) pain (no: 0.047, mild: 0.089, moderate: 0.242, severe: 0.263; P<0.0001). Post hoc, a cut-off value for NFSC (0.1) was calculated above which a pain score >3 on the NRS was predicted with sensitivity of 89% and specificity of 74%. CONCLUSIONS: The severity of postoperative pain significantly influences SC. Using cut-off values, NFSC may prove a useful tool for pain assessment in the postoperative period.

Adult↗
PubMed2006

The role of ketamine in pain management.

Ketamine is a dissociative anaesthetic; its mechanism of action is primarily an antagonism of the N-methyl-D-aspartate (NMDA) receptor. The role of ketamine, in particular in lower sub-anaesthetic doses, has recently gained increasing interest in pain management. It has been studied in a considerable number of trials and analysed in meta-analyses and systematic reviews. Based on these data, the primary role of ketamine in such low doses is as an 'anti-hyperalgesic', 'anti-allodynic' or 'tolerance-protective' agent. It therefore has a role in the treatment of opioid resistant or 'pathological' pain (central sensitisation with hyperalgesia or allodynia, opioid induced hyperalgesia, neuropathic pain) rather than as an 'analgesic' in its own right. Low dose ketamine also has 'preventive analgesia' properties. Furthermore, in higher doses it provides effective and safe sedation and analgesia for painful procedures. The place of ketamine in the treatment of chronic pain and the effects of long-term medicinal use remain unclear.

Analgesics↗
PubMed2006

Skin conductance monitoring compared with bispectral index monitoring to assess emergence from general anaesthesia using sevoflurane and remifentanil.

BACKGROUND: Changes in skin conductance have previously been reported to correlate well with plasma levels of stress hormones and awakening stimuli. In this study, monitoring of skin conductance during emergence from general anaesthesia was compared with the monitoring of bispectral index (BIS). METHODS: Twenty-five patients undergoing minor elective surgery were investigated. The number of fluctuations in mean skin conductance (NFSC), BIS and haemodynamic parameters were recorded simultaneously. The performance of the monitoring devices to predict and distinguish between the clinical states 'steady-state anaesthesia', 'first reaction' and 'extubation' were compared using the method of prediction probability (P(K)) calculation. RESULTS: Both monitors showed similar performance in distinguishing between 'steady-state anaesthesia' vs 'first reaction' (P(K) NFSC 0.89; BIS 0.94) and 'steady-state anaesthesia' vs 'extubation' (P(K) NFSC 0.96; BIS 0.96). The response times of the monitors, to indicate the likelihood of 'first reaction', were not significantly different. CONCLUSIONS: NFSC, as a parameter of skin conductance, performed similarly to BIS in patients waking after a general anaesthetic.

Adolescent↗
PubMed2005

Opioid prescribing: an assessment using quality statements.

OBJECTIVE: An audit of opioid prescribing in a large teaching hospital across all specialties was conducted to identify areas for improvement. METHODS: Opioid medications prescribed for the entire patient admission were recorded and assessed using quality statements. RESULTS AND DISCUSSION: Of 334 patients reviewed 209 (62.6%) were prescribed an opioid. Poly-prescribing of 'when required' (p.r.n.) opioids was frequent with 107 (51.2%) patients having more than one 'p.r.n.' opioid. Dosing intervals were too long for 146 (69.8%) patients leaving them at risk of breakthrough pain. The intramuscular route was prescribed for 100 (47.8%) patients, and 49 (23.4%) of prescriptions had an inappropriate variety of administration routes. CONCLUSION: Although the criteria for assessing opioid prescribing were stringent the prescribing was sub-optimal. This survey will form the basis for future quality initiatives.

Analgesics, Opioid↗
PubMed2000

A comparison of the efficacy and safety of morphine and pethidine as analgesia for suspected renal colic in the emergency setting.

OBJECTIVES: The aim of this study was to compare morphine and pethidine in patients with clinically suspected renal colic with regard to analgesic efficacy, patient satisfaction and side effects. METHODS: double blinded, randomised controlled trial. RESULTS: There was no significant difference between morphine and pethidine with respect to any of the parameters measured. CONCLUSION: Because of the well known adverse effects that may be associated with pethidine use, the authors recommend that morphine should be the preferred agent in suspected renal colic, when an opioid analgesic is to be used.

Adolescent↗
PubMed1999

A comparison of epidural ropivacaine infusion alone and in combination with 1, 2, and 4 microg/mL fentanyl for seventy-two hours of postoperative analgesia after major abdominal surgery.

UNLABELLED: Our aim in this prospective, randomized, double-blinded study was to compare the analgesic effectiveness and side effects of epidural infusions with ropivacaine 2 mg/mL alone (Group R; n = 60) and in combination with fentanyl 1 microg/mL (R1F; n = 59), 2 microg/mL (R2F; n = 62), and 4 microg/mL (R4F; n = 63) for up to 72 h after major abdominal surgery. Effective epidural neural blockade was established before surgery; postoperatively, the infusion rate was titrated to a maximum of 14 mL/h for analgesia. No additional analgesics other than acetaminophen were permitted during the infusion. The median of individual visual analog scale score with coughing were <20 mm for all groups (0 = no pain, 100 = worst pain) and was significantly lower (P < 0.01) for Group R4F at rest and with coughing (compared with Group R). Infusions were discontinued due to inability to control pain in significantly fewer patients in Group R4F (16%) than the other groups (34% to 39%; P < 0.01). For all groups, >90% of patients had no detectable motor block after 24 h. Hypotension, nausea, and pruritus were more common with the larger dose of fentanyl. We conclude that, after major abdominal surgery, an epidural infusion of ropivacaine 2 mg/mL with fentanyl 4 microg/mL provided significantly more effective pain relief over a 3-day period than ropivacaine alone or ropivacaine with lower concentrations of fentanyl. IMPLICATIONS: Postoperative epidural analgesic infusions are widely used, but there is little information regarding optimal strengths of opioid with local anesthetic. In this blinded, prospective study, we compared four different epidural infusion solutions for efficacy and side effects over a clinically useful postoperative period and conclude that an epidural infusion of ropivacaine 2 mg/mL with fentanyl 4 microg/mL was most effective.

Abdomen↗
PubMed1999

New drugs for neuraxial blockade.

Recent years have seen a dramatic increase in the number of agents used for neuraxial blockade. Together with the developments in local anaesthetics and opioids, completely new categories of agents have been investigated for intrathecal and epidural use. A review of the recent literature reveals the potential for improvement in achieving balanced anaesthesia and analgesia, in particular combining agents to reduce adverse effects.

Journal Article↗
PubMed1999

Recent advances in the pharmacokinetics of local anaesthetics. Long-acting amide enantiomers and continuous infusions.

The most widely used long-acting amide local anaesthetic is bupivacaine, a racemic mixture of 2 stereoisomers. However, there is evidence that the use of single enantiomer compounds offers advantages over racemic agents. Ropivacaine, the recently introduced propyl homologue of bupivacaine, is a pure S-(-)-enantiomer. It is associated with a reduced incidence of both cardiovascular and central nervous system toxicity, a concern with racemic bupivacaine, in preclinical studies. The relevant pharmacokinetic differences include a lower lipid solubility, a slightly higher plasma clearance and shorter elimination half-life (t 1/2 beta) compared with racemic bupivacaine, with a similar degree of plasma protein binding. More recently levobupivacaine, the pure S-(-)-enantiomer of bupivacaine, has been produced. Stereoselective differences have been observed between the 2 enantiomers and the racemic mixture, with levobupivacaine exhibiting a slightly higher degree of plasma protein binding, a lower volume of distribution, a higher plasma clearance, and a shorter t 1/2 beta than the R-(+)-enantiomer. In common with ropivacaine, levobupivacaine has been shown to have a reduced incidence of toxicity in comparison the R-(+)-enantiomer in preclinical studies, explained in part by a reduced affinity to both brain and myocardial tissue. Racemic bupivacaine is increasingly administered by continuous infusion to provide prolonged postoperative analgesia. The pharmacokinetic profile of the drug administered in this manner has only recently been elucidated and indicates a slow rise in total plasma concentration with increasing duration of infusion, mitigated by changes in plasma protein concentrations during the postoperative period. This appears to be the predominant reason why complications related to systemic toxicity are rarely observed with this technique. However, continuous administration of individual enantiomers may potentially serve as a safer option in the future.

Amides↗
PubMed1998

Acetaminophen as an adjunct to morphine by patient-controlled analgesia in the management of acute postoperative pain.

UNLABELLED: Opioids play a fundamental role in the management of postoperative pain, but their use is associated with a number of side effects, including nausea and vomiting, sedation, and respiratory depression. Co-administration of a nonopioid has been proposed as a method of reducing opioid intake and minimizing side effects. Sixty-one ASA physical status I and II patients were enrolled in a double-blind, randomized, placebo-controlled, parallel study to investigate the effect of a combination of acetaminophen and morphine after open reduction and internal fixation of acute limb fractures. Patients were randomized to receive either oral acetaminophen (1 g every 4 h) or placebo as an adjuvant to morphine by patient-controlled analgesia (PCA) postoperatively. They were assessed daily for 72 h or until the PCA was discontinued according to standardized guidelines. The outcome variables collected were pain scores (11-point scale), amount of morphine self-administered, duration of PCA use, compliance with study design, incidence of nausea and sedation, and overall patient satisfaction. The acetaminophen group had lower pain scores on Day 1 (2.1 vs 3.3; P = 0.03) and a shorter average duration of PCA use (35.8 vs 45.5 h; P = 0.03). Overall patient satisfaction was also significantly greater in the acetaminophen group (8.7 vs 7.9; P = 0.04). These data suggest that acetaminophen is a useful adjunct to morphine PCA. IMPLICATIONS: This study assesses the benefit of combining two analgesics for the treatment of postoperative pain. Such a combination improves the quality of pain relief and patient satisfaction.

Acetaminophen↗
PubMed1997

[Influence of postoperative pain therapy on nausea and vomiting].

PROBLEM: Postoperative nausea and vomiting remains an important problem. Many risk factors have been identified; however, the importance of postoperative analgesic technique and patient expectation remain poorly defined. METHODS: We prospectively collected data on postoperative nausea and vomiting (PONV) in four groups of randomly selected patients (n=50 per group) who received either simple analgesics, nurse-administered intravenous morphine (NAA), patient-controlled analgesia (PCA) with morphine or epidural analgesia with bupivacaine and fentanyl. Patients were questioned regarding any past history of PONV or motion sickness, their preoperative expectation of suffering PONV and satisfaction with their antiemetic therapy. RESULTS: The incidence of nausea was higher in both morphine groups P<0.05), women (P<0.05), those less than the median age of their group (P<0.05) and those with a past history of PONV (P<0.05) or motion sickness (P<0.05). Most patients did not expect to experience PONV (19.3%). The incidence of nausea was higher in those expecting to experience PONV than in those not expecting to suffer PONV (P<0.01). Of those who received postoperative antiemetic treatment, 23.6% were dissatisfied or very dissatisfied with their therapy. Few patients received a prophylactic antiemetic drug (15%). CONCLUSIONS: Study results show that patient expectation is a potent predictor of postoperative nausea, a risk factor hitherto ignored in the anaesthetic literature, and that, in the provision of analgesia following major surgery, epidural analgesia is associated with less PONV than intravenous morphine.

English Abstract↗
PubMed1997

Pain control.

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Analgesics↗
PubMed1997

The safety and utilization of patient-controlled analgesia.

Between December 1989 and March 1996, more than 6000 patients were treated with patient-controlled analgesia (PCA) at Auckland Hospital. The overall incidence of potentially life-threatening complications was low (0.28%). A small number (276) received PCA with a background opioid infusion. This technique was associated with a higher incidence of such complications (1.08%, P < 0.05). To further characterize the safety and utilization of PCA, a subgroup of 300 patients was analyzed. The average duration of PCA was 76.4 +/- 39.2 hr. The peak morphine consumption was highest on the day of operation (45.4 +/- 37.0 mg) and rapidly declined over the next 3 postoperative days (40.6 +/- 39.0, 33.3 +/- 26.2, and 27.8 +/- 36.6 mg, respectively). The ratio of drug demands to deliveries decreased from 1.76 on the morning of the first postoperative day to 1.17 on the evening of the third. The percentage of patients with inadequate analgesia (pain score > or = 3/10) and an inability to comply with physiotherapy (Bruggemann comfort score < or = 2/10) was high on the first postoperative day (42% and 18%, respectively). Men used significantly more morphine than women (141.7 +/- 123.6 versus 102.7 +/- 111.2 mg, P < 0.0001) and general surgical patients used more morphine than urology and orthopedic patients (152.6 +/- 136.9 versus 96.0 +/- 84.2 and 83.7 +/- 97.9 mg, P < 0.0001). There was no association between morphine consumption and age (r = -0.216). Of the 6% of patients who experienced hypoxemia and 2% who experienced respiratory depression, virtually all had one of three risk factors: bolus dose greater than 1 mg morphine, age greater than 65 years, or intra-abdominal surgery. The most common side effects were nausea and sedation. The incidence of nausea was highest on day 1 (28%) and decreased over the next 2 days (14.3% and 4.7%, respectively). A similar pattern was observed with sedation (incidence over the first 3 days: 28%, 9.3%, and 3.3%, respectively). Overall patient satisfaction scores were high (8.3/10 +/- 1.9). We conclude that the risk of serious complications with PCA is very low, but worrying degrees of hypoxemia and bradypnea do occur. We suggest prescribing regimens that may reduce complications and identify patients at high risk.

Adult↗
PubMed1997

Stereochemistry in anaesthesia.

1. Interest in the pharmacokinetic and pharmacodynamic properties of the enantiomers of chiral drugs has greatly increased in recent years. This is particularly so for agents used in anaesthesia. 2. Chiral compounds are those that can exist in two nonsuperimposable forms. Each form is termed an enantiomer or stereoisomer. Two naming systems are in use: one uses the terms (+) and (-) to indicate the direction the compound will rotate polarized light, while the other system, based on the absolute three-dimensional structure of the enantiomers, uses the terms R and S. 3. Investigation of the stereoisomers of the volatile anaesthetic agent isoflurane is increasing our understanding of the mechanism of general anaesthesia. Current evidence suggests a protein, rather than a lipid, receptor site. 4. Investigation of the stereoisomers of local anaesthetics is increasing the safety of these drugs. 5. For bupivacaine, a widely used amide local anaesthetic, important enantiomeric differences can be found for toxicity, clinical effect and pharmacokinetics. In particular S-(-)-bupivacaine has an improved central nervous system and cardiac safety profile. This is partly explained by the pharmacokinetic differences. 6. Based on these differences, ropivacaine, a propyl homologue of bupivacaine, has been produced solely as the S-(-)-enantiomer. The available evidence suggests significantly improved safety for this agent over racemic bupivacaine.

Anesthetics, General↗