S. Alahuhta

A survey of postoperative nausea and vomiting.

A prospective interview‐based survey on the incidence of postoperative nausea and vomiting in 1107 in‐patients aged 4–86 years was conducted during a 3‐month period. Nausea, emetic episodes and the need for anti‐emetic medication were recorded for 24 h postoperatively. In the recovery room, the incidence of nausea and vomiting was 18% and 5%, respectively. Over the whole 24‐h period, these figures were 52% and 25%, respectively; severe nausea was experienced by 8%. The highest incidence of emetic sequelae was observed in gynaecological patients; 52% of the 822 patients who received general anaesthesia and 38% of the 285 patients who received regional anaesthesia reported nausea. The most important predictive factors associated with an increased risk for nausea and vomiting were female gender, a previous history of postoperative sickness, a longer duration of surgery, nonsmoking and a history of motion sickness. Based on these five items, a simple score predicting the risk of nausea and vomiting was constructed with a moderately good discriminating power.

Persistent default-mode network connectivity during light sedation

The default‐mode network (DMN) is a set of specific brain regions whose activity, predominant in the resting‐state, is attenuated during cognitively demanding, externally‐cued tasks. The cognitive correlates of this network have proven difficult to interrogate, but one hypothesis is that regions in the network process episodic memories and semantic knowledge integral to internally‐generated mental activity. Here, we compare default‐mode functional connectivity in the same group of subjects during rest and conscious sedation with midazolam, a state characterized by anterograde amnesia and a reduced level of consciousness. Although the DMN showed functional connectivity during both rest and conscious sedation, a direct comparison found that there was significantly reduced functional connectivity in the posterior cingulate cortex during conscious sedation. These results confirm that low‐frequency oscillations in the DMN persist and remain highly correlated even at reduced levels of consciousness. We hypothesize that focal reductions in DMN connectivity, as shown here in the posterior cingulate cortex, may represent a stable correlate of reduced consciousness. Hum Brain Mapp, 2008.

Remifentanil in obstetric analgesia: A dose-finding study

IV patient-controlled analgesia (PCA) with remifentanil is a new approach in systemic opioid analgesia during labor. We determined the minimum effective dose of IV remifentanil by increasing the PCA bolus from 0.2 &mgr;g/kg with 0.2 &mgr;g/kg increments during a 60-min study period until the analgesia was considered adequate by the parturient. Twenty healthy parturients with singleton pregnancies participated in the study during the first stage of labor. Remifentanil hydrochloride was given IV via PCA over 1 min with a lockout time of 1 min. The parturient started the PCA bolus at the first subjective sign of uterine contraction. All 17 patients who completed the study reached adequate pain relief. The median effective PCA bolus was 0.4 &mgr;g/kg and consumption was 0.066 &mgr;g · kg−1 · min−1, with wide individual variation (0.2–0.8 &mgr;g/kg and 0.027–0.207 &mgr;g · kg−1 · min−1, respectively). The pain scores were reduced by a median of 4.2 (25th–75th percentiles, 3.1–5.2;P < 0.001) on an 11-point numeric scale. Although there was a wide individual variation in the dose required, remifentanil seems effective for labor analgesia. However, maternal oxygen desaturation, sedation, and reduced fetal heart rate beat-to-beat variability were observed frequently. There was wide individual variation in the dose required for effective labor analgesia. Potentially serious side effects, which were observed frequently during remifentanil analgesia, may limit remifentanil’s use in obstetrics.

Nordic guidelines for neuraxial blocks in disturbed haemostasis from the Scandinavian Society of Anaesthesiology and Intensive Care Medicine.

Background: Central neuraxial blocks (CNBs) for surgery and analgesia are an important part of anaesthesia practice in the Nordic countries. More active thromboprophylaxis with potent antihaemostatic drugs has increased the risk of bleeding into the spinal canal. National guidelines for minimizing this risk in patients who benefit from such blocks vary in their recommendations for safe practice.

Comparison of remifentanil and nitrous oxide in labour analgesia

Background:  We compared the efficacy and side‐effects of remifentanil with those of nitrous oxide during the first stage of labour.

Intravenous remifentanil vs. epidural levobupivacaine with fentanyl for pain relief in early labour : a randomised, controlled, double-blinded study

Background: We hypothesised that intravenous patient‐controlled analgesia (IV PCA) with remifentanil could provide as satisfactory pain relief for labour as epidural analgesia.

Visceral pain during caesarean section under spinal and epidural anaesthesia with bupivacaine.

In a randomized study, the incidence of visceral pain was evaluated in 46 patients undergoing elective caesarean section under spinal or epidural anaesthesia with 0.5% bupivacaine. If the patient experienced pain during the operation, a standard visual analogue scale ranging from 0 to 10 was used to assess the degree of pain Visceral pain occurred in 12/23 patients in the spinal group and in 13/23 patients in the epidural group. In neither group was a correlation found between the cephalad level of analgesia or the intensity of cutaneous analgesia in the sacral region, and the presence of visceral pain.

BOLD signal increase preceeds EEG spike activity—a dynamic penicillin induced focal epilepsy in deep anesthesia

In 40-60% of cases with interictal activity in EEG, fMRI cannot locate any focus or foci with simultaneous EEG/fMRI. In experimental focal epilepsy, a priori knowledge exists of the location of the epileptogenic area. This study aimed to develop and to test an experimental focal epilepsy model, which includes dynamic induction of epileptic activity, simultaneous EEG/fMRI, and deep anesthesia. Reported results are from seven pigs (23 +/- 2 kg) studied under isoflurane anesthesia (1.2-1.6 MAC, burst-suppression EEG) and muscle relaxant. Hypo- and hypercapnia were tested in one pig. Penicillin (6000 IU) was injected via a plastic catheter (inserted into the somatosensory cortex) during fMRI (GRE-EPI, TE = 40 ms, 300 ms/two slices, acquisition delay 1700 ms) in 1.5 T (N = 6). Epileptic spikes between acquisition artifacts were reviewed and EEG total power calculated. Cross-correlation between voxel time series and three model functions resembling induced spike activity were tested. Activation map averages were calculated. Development of penicillin induced focal epileptic activity was associated with linear increase and saturation up to approximately 10-20%, in BOLD activation map average. Its initial linear increase reached 2.5-10% at the appearance of the first distinguished spike in ipsilateral EEG in all six animals. Correlated voxels were located mainly in the vicinity of the penicillin injection site and midline, but few in the thalamus. In conclusion, development of focal epileptic activity can be detected as a BOLD signal change, even preceding the spike activity in scalp EEG. This experimental model contains potential for development and testing different localization methods and revealing the characteristic time sequence of epileptic activity with fMRI during deep anesthesia.

The effects of epidural ropivacaine and bupivacaine for cesarean section on uteroplacental and fetal circulation.

Background Ropivacaine is a new long-acting amide local anesthetic that has been shown in animal studies to have less dysrhythmogenic and cardiotoxic potential than bupivacaine. The intravenous administration of ropivacaine has not been associated with any detrimental effects on uterine blood flow in pregnant ewes. The purpose of this randomized, double-blind study was to examine the effects of epidural ropivacaine for cesarean section on blood flow velocity waveforms in uteroplacental and fetal arteries with color Doppler ultrasound and to assess whether the block modified fetal myocardial function.

Two instances of central nervous system toxicity in the same patient following repeated ropivacaine-induced brachial plexus block

We describe two instances of central nervous system (CNS) toxicity in the same patient following repeated brachial plexus blocks induced by high doses of ropivacaine (6 mg · kg−1 and 4.5 mg · kg−1, respectively). Although very high total and free plasma concentrations of ropivacaine were found up to 98 min after induction of the blocks, no signs of cardiovascular toxicity apart from hypertension and sinus tachycardia were observed. The measured plasma concentrations are the highest so far reported in the literature. We conclude that this case demonstrates the high cardiovascular safety level of ropivacaine. These high doses, however, resulted in severe toxic CNS symptoms. Therefore, it is stressed that the dose in relation to the weight of the patient must be calculated when administering a large volume of local anesthetic.