Suboptimal reliability of FIB-4 and NAFLD-fibrosis scores for staging of liver fibrosis in general population

Background and Aim

The burden and incidence of liver cirrhosis are increasing worldwide. Early detection of liver fibrosis would help in early interventions and preventing the progression of fibrosis and cirrhosis. The accepted noninvasive markers for liver fibrosis staging, namely fibrosis-4 (FIB-4) and nonalcoholic fatty liver disease fibrosis score (NFS), have shown inconsistent performance for detecting the fibrosis stage. We aimed to evaluate the efficacy of FIB-4 score and NFS for the detection of liver fibrosis in the general population.

Methods

From a general population referred from a single, community-based family-physician clinic, we included study participants between the ages of 45 and 65 years, with no knowledge of liver disease and no record of alcohol consumption. Liver fibrosis was evaluated by the FIB-4 score and NFS using shear wave elastography (SWE) or transient elastography (TE) measurements as a reference.

Results

A total of 76 participants (aged 61.5 ± 0.37 years, 33% females) were included in the study cohort. We observed a nonsignificant correlation between liver stiffness measurement (LSM) and FIB-4 and NFS (r = 0.1, P = 0.37; r = 0.16, P = 0.15, respectively). Our results showed that only 5.2% with FIB-4 >3.25 and 9.7% with NFS >0.675 had LSM >12 kPa. The compatibility of fibrosis staging was 55% between FIB-4 score and LSM and only 18% between NFS and LSM.

Conclusion

We found that FIB-4 and NFS are unreliable tools for liver fibrosis estimation in the general population. There is a need for more reliable noninvasive methods for the early detection of liver fibrosis.

Role of cosyntropin in the management of postpartum post-dural puncture headache: a two-center retrospective cohort study

BACKGROUND

Research suggests that postpartum post-dural puncture headache (PDPH) might be prevented or treated by administering intravenous cosyntropin.

METHODS

In this retrospective cohort study, we questioned whether prophylactic (1 mg) and therapeutic (7 µg/kg) intravenous cosyntropin following unintentional dural puncture (UDP) was effective in decreasing the incidence of PDPH and therapeutic epidural blood patch (EBP) after birth. Two tertiary-care American university hospitals collected data from November 1999 to May 2017. Two hundred and fifty-three postpartum patients who experienced an UDP were analyzed. In one institution 32 patients were exposed to and 32 patients were not given prophylactic cosyntropin; in the other institution, once PDPH developed, 36 patients were given and 153 patients were not given therapeutic cosyntropin. The primary outcome for the prophylactic cosyntropin analysis was the incidence of PDPH and for the therapeutic cosyntropin analysis in exposed vs. unexposed patients, the receipt of an EBP. The secondary outcome for the prophylactic cosyntropin groups was the receipt of an EBP.

RESULTS

In the prophylactic cosyntropin analysis no significant difference was found in the risk of PDPH between those exposed to cosyntropin (19/32, 59%) and unexposed patients (17/32, 53%; odds ratio (OR) 1.37, 95% CI 0.48 to 3.98, P = 0.56), or in the incidence of EBP between exposed (12/32, 38%) and unexposed patients (6/32, 19%; OR 2.6, 95% CI 0.83 to 8.13, P = 0.095). In the therapeutic cosyntropin analysis, in patients exposed to cosyntropin the incidence of EBP was significantly higher (20/36, 56% vs. 43/153, 28%; OR 3.20, 95% CI 1.52 to 6.74, P = 0.002).

CONCLUSIONS

Our data show no benefits from the use of cosyntropin for preventing or treating postpartum PDPH.

Risk factors for persistent pain after breast cancer surgery: a multicentre prospective cohort study

Identifying factors associated with persistent pain after breast cancer surgery may facilitate risk stratification and individualised management. Single-population studies have limited generalisability as socio-economic and genetic factors contribute to persistent pain development. Therefore, this prospective multicentre cohort study aimed to develop a predictive model from a sample of Asian and American women. We enrolled women undergoing elective breast cancer surgery at KK Women's and Children's Hospital and Duke University Medical Center. Pre-operative patient and clinical characteristics and EQ-5D-3L health status were recorded. Pain catastrophising scale; central sensitisation inventory; coping strategies questionnaire-revised; brief symptom inventory-18; perceived stress scale; mechanical temporal summation; and pressure-pain threshold assessments were performed. Persistent pain was defined as pain score ≥ 3 or pain affecting activities of daily living 4 months after surgery. Univariate associations were generated using generalised estimating equations. Enrolment site was forced into the multivariable model, and risk factors with p < 0.2 in univariate analyses were considered for backwards selection. Of 210 patients, 135 (64.3%) developed persistent pain. The multivariable model attained AUC = 0.807, with five independent associations: age (OR 0.85 95%CI 0.74-0.98 per 5 years); diabetes (OR 4.68, 95%CI 1.03-21.22); pre-operative pain score at sites other than the breast (OR 1.48, 95%CI 1.11-1.96); previous mastitis (OR 4.90, 95%CI 1.31-18.34); and perceived stress scale (OR 1.35, 95%CI 1.01-1.80 per 5 points), after adjusting for: enrolment site; pre-operative pain score at the breast; pre-operative overall pain score at rest; postoperative non-steroidal anti-inflammatory drug use; and pain catastrophising scale. Future research should validate this model and evaluate pre-emptive interventions to reduce persistent pain risk.

Obesity in women: anaesthetic implications for peri-operative and peripartum management

The prevalence, healthcare and socio-economic impact of obesity (defined as having a body mass index of ≥ 30 kg.m^-2 ) are disproportionately higher in women than men. A combination of biological and social factors, including the adaptation of energy homeostasis to the increased demands of pregnancy and lactation and poor access to healthy foods or exercise facilities, contribute to the increasing prevalence of obesity in women. Obesity-related physiological changes stem from mass loading and increased metabolism of adipose tissue, as well as secretion of bioactive substances from adipocytes leading to chronic low-grade inflammation. As a result, obesity is associated with increased risks of: infertility; malignancy; sleep-disordered breathing; cardiovascular disease; diabetes; and thromboembolism. Hence, obese women are at markedly increased risk of peri-operative morbidity and mortality and require comprehensive evaluation and targeted comorbidity optimisation by a multidisciplinary team. In addition to routine obstetric challenges, pregnancy in women with obesity further exacerbates the above risks, making multidisciplinary management starting at pre-conception even more important. Weight loss, lifestyle management and optimisation of comorbidity are the cornerstone of reducing obesity-related risks. The anaesthetist plays a vital role within the multidisciplinary team by emphasising weight loss as part of pre-operative comorbidity optimisation, formulation of individualised peri-operative management plans, supervising postoperative care in the high dependency or intensive care settings and providing safe labour analgesia and careful peripartum management for obese parturients.

Tonic-clonic seizure after unrecognized unintentional dural puncture

Patients who suffer an unintentional dural puncture have a high risk of developing a post-dural puncture headache. Other neurologic complications have been reported, but seizure is rarely seen. We present a case of a 21-year-old primigravida who experienced an unrecognized unintentional dural puncture that ultimately resulted in a tonic-clonic seizure from intracranial hypotension one week following the dural breach. Her trachea was intubated and she was transferred to the intensive care unit. Two epidural blood patches, performed by neuroradiologists, were needed before the patient experienced complete resolution of her headache. During the re-admission, she also experienced a pulmonary embolus which further lengthened her hospital stay.

Anesthetic management of parturients with Arnold Chiari malformation-I: a multicenter retrospective study

BACKGROUND

Consensus regarding the safest mode of delivery and anesthetic management for parturients with Arnold Chiari malformation-I (ACM-I) remains controversial. This study assessed their anesthetic management and reported anesthetic complications during hospitalization for delivery.

METHODS

This was a multicenter, retrospective, cohort study of patients with ACM-I undergoing vaginal or cesarean delivery. Data were obtained from the electronic databases of four United States academic institutions using International Classification of Diseases (ICD) codes from 2007-2017 at three sites and 2004-2017 at one site. The primary outcome was anesthetic complications.

RESULTS

Data were analyzed for 185 deliveries in 148 patients. Diagnosis of ACM-I was made prior to delivery in 147 (80%) cases. Pre-delivery neurosurgical consultation for management of ACM-I was performed in 53 (36%) patients. Pre-existing symptoms were recorded for 89 (48%) of the deliveries. Vaginal deliveries occurred in 80 (43%) cases, and 62 women (78%) received neuraxial labor analgesia. Cesarean delivery was performed in 105 (57%) cases, of which 70 women (67%) had neuraxial anesthesia and 34 (32%) received general anesthesia. Post-dural puncture headache was reported in three (2%) patients who had neuraxial anesthesia, and in two (12%) patients with syringomyelia. There was one (3%) reported case of aspiration pneumonia with general anesthesia.

CONCLUSIONS

The findings suggest that anesthetic complications occur infrequently in patients with ACM-I regardless of the anesthetic management. Although institutional preference in anesthetic and obstetric care appears to drive patient management, the findings suggest that an individualized approach has favorable outcomes in this population.

The impact of neuraxial clonidine on postoperative analgesia and perioperative adverse effects in women having elective Caesarean section-a systematic review and meta-analysis

Neuraxial clonidine improves postoperative analgesia in the general surgical population. The efficacy and safety of neuraxial clonidine as a postoperative analgesic adjunct in the Caesarean section population still remains unclear. This systematic review and meta-analysis aims to evaluate the effect of perioperative neuraxial clonidine on postoperative analgesia in women having Caesarean section under neuraxial anaesthesia. We included randomized controlled trials comparing the analgesic efficacy of the perioperative administration of neuraxial clonidine alone or in combination with a local anaesthetic and/or opioids in women having elective Caesarean section under neuraxial anaesthesia when compared with placebo. PubMed, the Cochrane Central Register of Controlled Trials, and EMBASE were searched until February 2017. Eighteen studies were included in the meta-analysis. Neuraxial clonidine reduced 24 h morphine consumption [mean difference (MD): -7.2 mg; 95% confidence interval (CI): -11.4, -3.0 mg; seven studies] and prolonged time to first analgesic request (MD: 135 min; 95% CI: 102, 168 min; 16 studies) when compared with the control group. Neuraxial clonidine increased intraoperative hypotension [odds ratio (OR): 2.849; 95% CI: 1.363, 5.957], intraoperative sedation (OR: 2.355; 95% CI: 1.016, 5.459), but reduced the need for intraoperative analgesic supplementation (OR: 0.224; 95% CI: 0.076, 0.663). The effect of clonidine on intraoperative bradycardia, intraoperative and postoperative nausea and vomiting, postoperative sedation, and pruritus were inconclusive. Neuraxial clonidine did not negatively impact neonatal umbilical artery pH or Apgar scores. This review demonstrates that neuraxial clonidine enhances postoperative analgesia in women having Caesarean section with neuraxial anaesthesia, but this has to be balanced against increased maternal adverse effects.

The Effect of patient warming during Caesarean delivery on maternal and neonatal outcomes: a meta-analysis

BACKGROUND

Perioperative warming is recommended for surgery under anaesthesia, however its role during Caesarean delivery remains unclear. This meta-analysis aimed to determine the efficacy of active warming on outcomes after elective Caesarean delivery.

METHODS

We searched databases for randomized controlled trials utilizing forced air warming or warmed fluid within 30 min of neuraxial anaesthesia placement. Primary outcome was maximum temperature change. Secondary outcomes included maternal (end of surgery temperature, shivering, thermal comfort, hypothermia) and neonatal (temperature, umbilical cord pH and Apgar scores) outcomes. Standardized mean difference/mean difference/risk ratio (SMD/MD/RR) and 95% confidence interval (CI) were calculated using random effects modelling (CMA, version 2, 2005).

RESULTS

13 studies met our criteria and 789 patients (416 warmed and 373 controls) were analysed for the primary outcome. Warming reduced temperature change (SMD -1.27°C [-1.86, -0.69]; P=0.00002); resulted in higher end of surgery temperatures (MD 0.43 °C [0.27, 0.59]; P<0.00001); was associated with less shivering (RR 0.58 [0.43, 0.79]; P=0.0004); improved thermal comfort (SMD 0.90 [0.36, 1.45]; P=0.001), and decreased hypothermia (RR 0.66 [0.50, 0.87]; P=0.003). Umbilical artery pH was higher in the warmed group (MD 0.02 [0, 0.05]; P=0.04). Egger's test (P=0.001) and contour-enhanced funnel plot suggest a risk of publication bias for the primary outcome of temperature change.

CONCLUSIONS

Active warming for elective Caesarean delivery decreases perioperative temperature reduction and the incidence of hypothermia and shivering. These findings suggest that forced air warming or warmed fluid should be used for elective Caesarean delivery.

Anesthetic management of super-morbidly obese parturients for cesarean delivery with a double neuraxial catheter technique: a case series

Parturients with super-morbid obesity, defined as body mass index greater than 50kg/m(2), represent a growing segment of patients who require anesthetic care for labor and delivery. Severe obesity and its comorbid conditions place the parturient and fetus at greater risk for pregnancy complications and cesarean delivery, as well as surgical and anesthetic complications. The surgical approach for cesarean delivery in these patients may require a supra-umbilical vertical midline incision due to a large pannus. The dense T4-level of spinal anesthesia can cause difficulties with ventilation for the obese patient during the procedure, which can be prolonged. Patients also may have respiratory complications in the postoperative period due to pain from the incision. We describe the anesthetic management of three parturients with body mass index ranging from 73 to 95kg/m(2) who had a cesarean delivery via a supra-umbilical vertical midline incision. Continuous lumbar spinal and low thoracic epidural catheters were placed in each patient for intraoperative anesthesia and postoperative analgesia, respectively. Continuous spinal catheters were dosed with incremental bupivacaine boluses to achieve surgical anesthesia. In one case, the patient required respiratory support with non-invasive positive pressure ventilation. Two cases were complicated by intraoperative hemorrhage. All patients had satisfactory postoperative analgesia with a thoracic epidural infusion. None suffered postoperative respiratory complications or postdural puncture headache. The use of a continuous lumbar spinal catheter and a low thoracic epidural provides several advantages in the anesthetic management of super-morbidly obese parturients for cesarean delivery.

Sheehan syndrome: acute presentation with severe headache

Postpartum headache is a common occurrence with a broad differential diagnosis. Sheehan syndrome, or postpartum pituitary necrosis, is not typically recognized as a cause of postpartum headache. We present a case of Sheehan syndrome that initially presented as severe headache after vaginal delivery complicated by retained placenta and postpartum hemorrhage. The patient was discharged home on postpartum day three but continued to have headaches and returned to hospital on postpartum day six with severe headache, failure to lactate, edema, dizziness, fatigue, nausea and vomiting. Cranial magnetic resonance imaging revealed pituitary infarction consistent with Sheehan syndrome. We discuss the differential diagnosis for postpartum headache, the pathophysiological features of Sheehan syndrome and headache as an atypical acute presentation.

Impact of perioperative dexamethasone on postoperative analgesia and side-effects: systematic review and meta-analysis

BACKGROUND

The analgesic efficacy and adverse effects of a single perioperative dose of dexamethasone are unclear. We performed a systematic review to evaluate the impact of a single i.v. dose of dexamethasone on postoperative pain and explore adverse events associated with this treatment.

METHODS

MEDLINE, EMBASE, CINAHL, and the Cochrane Register were searched for randomized, controlled studies that compared dexamethasone vs placebo or an antiemetic in adult patients undergoing general anaesthesia and reported pain outcomes.

RESULTS

Forty-five studies involving 5796 patients receiving dexamethasone 1.25-20 mg were included. Patients receiving dexamethasone had lower pain scores at 2 h {mean difference (MD) -0.49 [95% confidence interval (CI): -0.83, -0.15]} and 24 h [MD -0.48 (95% CI: -0.62, -0.35)] after surgery. Dexamethasone-treated patients used less opioids at 2 h [MD -0.87 mg morphine equivalents (95% CI: -1.40 to -0.33)] and 24 h [MD -2.33 mg morphine equivalents (95% CI: -4.39, -0.26)], required less rescue analgesia for intolerable pain [relative risk 0.80 (95% CI: 0.69, 0.93)], had longer time to first dose of analgesic [MD 12.06 min (95% CI: 0.80, 23.32)], and shorter stays in the post-anaesthesia care unit [MD -5.32 min (95% CI: -10.49 to -0.15)]. There was no dose-response with regard to the opioid-sparing effect. There was no increase in infection or delayed wound healing with dexamethasone, but blood glucose levels were higher at 24 h [MD 0.39 mmol litre(-1) (95% CI: 0.04, 0.74)].

CONCLUSIONS

A single i.v. perioperative dose of dexamethasone had small but statistically significant analgesic benefits.

Metoclopramide for nausea and vomiting prophylaxis during and after Caesarean delivery: a systematic review and meta-analysis

Nausea and vomiting occur commonly during and after Caesarean delivery (CD) performed under neuraxial anaesthesia. Metoclopramide is a prokinetic agent reported to be safe in parturients. This meta-analysis assesses the efficacy of metoclopramide for prophylaxis against intra- and postoperative nausea and vomiting (IONV and PONV) in parturients undergoing CD under neuraxial anaesthesia. We performed a literature search of MEDLINE (1966-2011), Cochrane Central Register of Controlled Trials, EMBASE (1947-2011), Google scholar, and CINAHL for randomized controlled trials which compared metoclopramide with placebo in women having CD under neuraxial anaesthesia. Eleven studies with 702 patients were included in the analysis. Administration of metoclopramide (10 mg) resulted in a significant reduction in the incidence of ION and IOV when given before block placement [relative risk (RR) (95% confidence interval, 95% CI)=0.27 (0.16, 0.45) and 0.14 (0.03, 0.56), respectively] or after delivery [RR (95% CI)=0.38 (0.20, 0.75) and 0.34 (0.18, 0.66), respectively]. The incidence of early (0-3 or 0-4 h) PON and POV [RR (95% CI)=0.47 (0.26, 0.87) and 0.45 (0.21, 0.93), respectively] and overall (0-24 or 3-24 h) PON (RR 0.69; 95% CI 0.52, 0.92) were also reduced with metoclopramide. Extra-pyramidal side-effects were not reported in any patient. In conclusion, this review suggests that metoclopramide is effective and safe for IONV and PONV prophylaxis in this patient population. Given the quality of the studies and the infrequent use of neuraxial opioids, these results should be interpreted with caution in current practice and further studies are needed to confirm those findings.

Peripartum management of two parturients with ornithine transcarbamylase deficiency

Ornithine transcarbamylase deficiency is a rare X-linked disorder in which female carriers are usually heterozygous for the ornithine transcarbamylase deficiency gene. In pregnancy it has been associated with altered mental status, seizures, coma and death, especially in the postpartum period. We report the management of labor and delivery in two parturients with known ornithine transcarbamylase deficiency. Both patients were maintained on arginine, citrulline and sodium phenylacetate therapy with restricted protein intake during pregnancy. Neuraxial techniques were used for pain relief in labor and anesthesia for operative delivery. A dextrose infusion provided caloric intake during labor and perioperatively.

Minimum effective dose of spinal ropivacaine with and without fentanyl for postpartum tubal ligation

BACKGROUND

Ropivacaine may be the ideal spinal anesthetic for postpartum tubal ligation due to its medium duration of action, low incidence of side effects and possibly reduced post-anesthetic care unit (PACU) stay.

METHODS

Two prospective up-down sequential allocation studies were performed using hyperbaric spinal ropivacaine via a combined spinal-epidural anesthetic technique for patients undergoing postpartum tubal ligation. The first study was performed using an initial dose of 12.5 mg hyperbaric ropivacaine, which was adjusted in testing intervals of 0.5 mg. The second study used an initial dose of 16 mg hyperbaric ropivacaine, a testing interval of 1.0mg, and a fixed dose of fentanyl 10 μg. The need to supplement the block with intravenous or epidural agents was defined as a failure. Failures were treated with epidural lidocaine.

RESULTS

The first and second studies recruited 24 and 17 patients, respectively. The median effective dose (ED50) for hyperbaric spinal ropivacaine was 16.4 mg (95% CI 13.7-19) with an ED95 estimate of 21.9 mg. The median effective dose of spinal ropivacaine with fentanyl 10 μg was 17.0 mg (95% CI 15.4-18.7) with an ED95 estimate of 21.3 mg. When data were combined, the overall ED50 for ropivacaine was 16.7 mg (95% CI 15.1-18.4) with an ED95 estimate of 22.5 mg (95% CI 16.3-28.8). A T8 block was not achieved in 4 patients receiving spinal ropivacaine alone, and 1 patient receiving spinal ropivacaine with fentanyl. The majority (82%) of patients who did not receive epidural local anesthetic supplementation had recovery of motor block within 60 min following PACU admission.

CONCLUSION

Spinal hyperbaric ropivacaine 22 mg with or without fentanyl 10 μg could be used for postpartum tubal ligation surgery.

Ex utero intrapartum treatment procedure in a patient with arthrogryposis multiplex congenita, using continuous spinal anesthesia and intravenous nitroglycerin for uterine relaxation

The ex utero intrapartum treatment procedure allows for the controlled management of a potentially life-threatening difficult airway in the newborn. General anesthesia has previously been reported for the management of this procedure. We report the use of continuous spinal anesthesia in conjunction with intravenous nitroglycerin for the ex utero intrapartum treatment procedure in a woman with arthrogryposis multiplex congenita, a rare syndrome characterized by rigid joints and limb contractures.

Anaesthetic management of a parturient with the postural orthostatic tachycardia syndrome: a case report

Postural orthostatic tachycardia syndrome encompasses a group of disorders characterized by orthostatic intolerance. We describe the anaesthetic management of analgesia for labour and of Caesarean section in a parturient suffering from this disorder. Worsening of her symptoms during pregnancy was managed with an increase in the dose of beta-blockers taken by the patient. Epidural analgesia was instigated early to attenuate the stress of labour and avoid consequent triggering of a tachycardic response. Slow titration of epidural analgesia and anaesthesia after an adequate fluid preload was undertaken to minimize hypotension and subsequent tachycardia. Neuraxial opioid, combined with non-steroidal anti-inflammatory drugs and bilateral iliohypogastric and ilioinguinal nerve blocks were used to optimize postoperative analgesia.

A randomized, prospective double-blind comparison of the efficacy of generic propofol (sulphite additive) with Diprivan®

BACKGROUND AND OBJECTIVE

We compared the dose requirement and side effect profile of total intravenous anaesthesia using Diprivan to generic propofol at a specific anaesthetic target level utilizing the bispectral index monitor to determine efficacy differences between the two products.

METHODS

Sixty women undergoing abdominal hysterectomy were induced with propofol 2 mg kg-1 and maintained with infusion (20-200 microg kg-1 min-1) adjusted to maintain a bispectral index of 50-65. Plasma propofol concentration was measured at 1 and 2 h post induction in 25 patients.

RESULTS

Mean (SD) drug doses adjusted for weight and time were similar in the Diprivan and generic propofol groups: 90 (30) microg kg-1 min-1 vs. 90 (20) microg kg-1 min-1 respectively. Mean (SD) plasma propofol levels at 1 and 2 h were also similar (3.0 (1.0) microg mL-1 vs. 3.6 (1.4) microg mL-1, P = 0.2 and 3.0 (1.9) microg mL-1 vs. 3.4 (1.6) microg mL-1, P = 0.58).

CONCLUSIONS

Diprivan and generic propofol have similar efficacy at a specified, bispectral index-defined, depth of anaesthesia.

Dural ectasia: a likely cause of inadequate spinal anaesthesia in two parturients with Marfan's syndrome

We report two cases of Caesarean section in patients with Marfan's syndrome where continuous subarachnoid anaesthesia failed to provide an adequate surgical block. This was possibly because of dural ectasia, which was confirmed by a computed tomography scan in both cases.

Effects of remifentanil and alfentanil on the cardiovascular responses to induction of anaesthesia and tracheal intubation in the elderly

BACKGROUND

We compared the effects of remifentanil and alfentanil on arterial pressure and heart rate at induction of anaesthesia and tracheal intubation in 40 ASA I-III patients aged greater than 65 yr, in a randomized double-blind study.

METHODS

Patients received either remifentanil 0.5 microg kg(-1) over 30 s, followed by an infusion of 0.1 microg kg min(-1) (group R) or alfentanil 10 microg kg(-1) over 30 s, followed by an infusion of saline (group A). Anaesthesia was then induced with propofol, rocuronium, and 1% isoflurane with 66% nitrous oxide in oxygen.

RESULTS

Systolic arterial pressure (SAP) and mean arterial pressure (MAP) decreased after the induction of anaesthesia (P<0.05) and increased for 3 min after intubation in both groups (P<0.05), but remained below baseline values throughout. Heart rate remained stable after induction of anaesthesia but increased significantly from baseline after intubation for 1 and 4 min in groups R and A, respectively (P<0.05). There were no significant between-group differences in SAP, MAP, and heart rate. Diastolic pressure was significantly higher in group A than group R at 4 and 5 min after intubation (P<0.05). Hypotension (SAP < 100 mm Hg) occurred in four patients in group R and three patients in group A.

CONCLUSIONS

Remifentanil and alfentanil similarly attenuate the pressor response to laryngoscopy and intubation, but the incidence of hypotension confirms that both drugs should be used with caution in elderly patients.

Use of the bispectral index to monitor anaesthesia

In October 1996, the Food and Drug Administration approved the use of the first anaesthesia effect monitor in the USA: the bispectral index (BIS) monitor (Aspect MS®, Newton, MA). The BIS is a computer-processed electro-encephalography (EEG) variable, which results in a single number, ranging from 0 (isoelectric EEG) to 100 in the awake state. It is derived by combining several different EEG descriptors: the BetaRatio, the SynchFastSlow and a measure of burst suppression (Rampil, 1998).