Carbetocin for prevention of postcesarean hemorrhage in women with severe preeclampsia: a before-after cohort comparison with oxytocin

STUDY OBJECTIVE

The aim of the study was to compare the incidence of the use of additional uterotonics before and after the change of carbetocin to oxytocin for the prevention of postpartum hemorrhage after cesarean delivery in women with severe preeclampsia.

DESIGN

This was an observational retrospective before-and-after study.

SETTING

Operating room, postoperative recovery area.

PATIENTS

Sixty women with severe preeclampsia undergoing cesarean delivery under spinal anesthesia; American Society of Anesthesiologists 3.

INTERVENTIONS

Observational study.

MEASUREMENTS

Blood pressure, heart rate, and biological data (hemoglobin, platelets, haptoglobin, prothrombin time index, activated partial thromboplastin time ratio, blood uric acid, aspartate aminotransferase, alanine aminotransferase, serum urea, serum creatinine, and albumin).

MAIN RESULTS

The incidence of additional uterotonic administration in the carbetocin and oxytocin groups was 15% and 10%, respectively (P=.70).

CONCLUSIONS

As carbetocin appears to be as effective and safe as oxytocin in preeclamptic women, its advantages make it a good uterotonic option in this particular setting.

Preoperative fasting does not affect haemodynamic status: a prospective, non-inferiority, echocardiography study

BACKGROUND

The link between preoperative fasting and hypovolaemia remains unclear. We tested the hypothesis that preoperative fasting does not significantly increase the proportion of patients with hypovolaemia according to transthoracic echocardiography (TTE) criteria.

METHODS

Patients of ASA status I-III and without bowel preparation were included in a non-inferiority, prospective, single-centre trial. Patients underwent passive leg raising (PLR) test and TTE at admission (Day 0) and after 8 h fasting (Day 1). The primary hypothesis was that an 8 h preoperative fasting does not increase the proportion (margin=5%) of patients with a positive PLR test ('functional approach'). The secondary hypothesis was that echocardiographic filling pressures or stroke volume (margin 10%) are not affected by preoperative fasting ('static approach').

RESULTS

One hundred patients were included and 98 analysed. After an 8 h fasting, the change in the proportion of responders to PLR was -6.1% [95% confidence interval (CI)=-16.0 to 3.8] of responders to PLR test on Day 0 when compared with Day 1. Because 95% CI was strictly inferior to 5%, there was no significant increase in the proportion of PLR responders on Day 1 when compared with Day 0. The 95% CI changes of static variables were always fewer than 10%, meaning that preoperative fasting induced significantly no relevant changes in static variables.

CONCLUSION

Preoperative fasting did not alter TTE dynamic and static preload indices in ASA I-III adult patients. These results suggest that preoperative fasting does not induce significant hypovolaemia. Clinical trial registration NCT 01258361.

[Controversies in neuroanaesthesia: positioning in neurosurgery]

Positioning of the neurosurgical patient has several features such as the existence of specific positions (i.e: sitting, prone hyperlordotic, crouching ou kneeling positions) or the range of facilities for the same surgical indications. The last point, a source of controversy, is the subject of this review. Current indications for the sitting position, positioning for lumbar spine surgery and prevention of eye injuries are successively addressed.

Regional anaesthesia practice for total knee arthroplasty: French national survey - 2008

BACKGROUND AND OBJECTIVE

Improved pain management techniques and rehabilitation programs have significantly modified outcome for total knee arthroplasty (TKA).

OBJECTIVE

The aim of the survey was to describe the French practice patterns in regional anaesthesia for TKA.

METHODS

Twenty-item questionnaires were distributed to units with significant orthopaedic activity across France. The content referred to the type of orthopaedic activity; anaesthetic and analgesic management; preoperative patient information; technical aspects describing regional anaesthesia and postoperative analgesia.

RESULTS

Response rate was 54%. Combined general anaesthesia and perineural catheter was the most frequently used anaesthetic technique. Most of respondents used multimodal analgesia (including femoral nerve catheter by 80%). Written hygiene protocols were rarely available. Sterile gowns were seldom worn. Among antiseptic agents, povidone iodine was most often used. Sedative agents were systematically used by 36% of respondents. Ropivacaine was the preferred local anaesthetic agent. Finally, adjuvants were rarely used. In most cases (58%) the femoral block was performed before induction of general anaesthesia. The catheter was commonly threaded to a length between 5 and 8 cm. The correct position of the catheter tip was verified clinically by majority of respondents. Local anaesthetics were administered by continuous infusion, continuous infusion plus boluses and boluses alone in 44, 36 and 8% of cases. Catheter duration was 48 and 72 h in 45 and 33% of the units and was independent of pain scores.

CONCLUSION

This national survey showed practices in accordance with recent guidelines as well as persistent challenges in regional anaesthesia for TKA.

[Puncture of the radial vein: a forgotten complication]

The superficial radial vein at the lateral edge of the inferior third of the forearm and of the wrist has strong anatomical relationship with the sensory superficial branch of the radial nerve. At this level, any venous puncture may be responsible for a lesion of this superficial part of the radial nerve. We report two cases of dysesthesia in the radial territory after this kind of puncture. This risk should not be neglected and venous puncture should be avoided in this area.

[Benefits and indications of xenon anaesthesia]

OBJECTIVE

To analyze the current knowledge related to xenon anaesthesia.

DATA SOURCES

References were obtained from computerized bibliographic research (Medline), recent review articles, the library of the service and personal files.

STUDY SELECTION

All categories of articles on this topic have been selected.

DATA EXTRACTION

Articles have been analyzed for biophysics, pharmacology, toxicity and environmental effects, clinical effects and using prospect.

DATA SYNTHESIS

The noble gas xenon has anaesthetic properties that have been recognized 50 years ago. Xenon is receiving renewed interest because it has many characteristics of an ideal anaesthetic. In addition to its lack of effects on cardiovascular system, xenon has a low solubility enabling faster induction of and emergence from anaesthesia than with other inhalational agents. Nevertheless, at present, the cost and rarity of xenon limits widespread use in clinical practice. The development of closed rebreathing system that allowed recycling of xenon and therefore reducing its waste has led to a recent interest in this gas.

CONCLUSION

Reducing its cost will help xenon to find its place among anaesthetic agents and extend its use to severe patients with specific pathologies.

[Anesthesia and preeclampsia]

An assessment of the patient must take place as early as possible in view of anaesthesia. It is recommended to perform a clotting screen as close as possible to the performing of an epidural anaesthesia. The use of aspirin, if indicated for the prevention of PE, does not as such, constitute a contraindication to performing an epidural anaesthesia if: With regards to the minimum platelet count, the recommended cut-off value for the performing of an epidural and spinal anaesthesia are 75 & 50 x 10(9)/l respectively, only if all of the following conditions are met: It is recommended to quickly set up an epidural anaesthesia because this will improve the blood pressure as well as the utero-placenteric haemodynamics and also because this will facilitate the management in case of a caesarean section. Whereas methylergometrine (Methergin) is contraindicated in the preeclamptic patient, it is possible to use oxytocin (Syntocinion) during and after labour. Before performing a spinal anaesthesia, it is recommended to restrain the administration of crystalloids to a maximum of 1000 ml. Also the i.v. antihypertensive treatment should be reduced or interrupted until complete establishment of the anaesthetic. In case a general anaesthesia is to be performed, an assessment of the criteria for difficult intubation should be performed immediately prior to the induction. The technique employed should be a rapid sequence induction with intubation, while preventing a surge in blood pressure induced by the tracheal intubation. Difficulties to extubate should systematically be anticipated. It is possible to perform a loco-regional anaesthesia following an eclamptic crisis if the following conditions are met: In case of overlapping seizures and/or impaired consciousness, a general anaesthesia is recommended.

[Hyaluronidase: Here we go again]

OBJECTIVE

To summarize the benefits and lateral effects of hyaluronidase (H) use in ophthalmologic anaesthesia and to address its unavailability in current practice in France.

DATA SOURCES

The Medline data bank and the Cochrane database were consulted. The keywords employed separately or in combination were: H, regional anaesthesia, ophthalmologic surgery, local aneasthetics myotoxicity, diplopia.

STUDY SELECTION

Original articles since 1949 were selected. We also selected isolated clinical cases according to their relevance compared with the existing literature.

DATA SYNTHESIS

H is a "spreading factor" of animal origin used as an adjuvant in ophthalmic anaesthesia for more than half a century. It allows a moderate better block quality with a slightly quicker onset. It also limits the acute intraocular pressure increase secondary to periocular injection and seems to have a protective effect against local anaesthetics myotoxicity resulting in postoperative strabismus. However, during these last 50 years, numerous studies often ended in divergent results.

CONCLUSION

H seems to be a useful adjuvant in ophthalmologic anaesthesia in spite of his current unavailability in France. Recombinant H could be the solution in the near future.

Could B-type Natriuretic Peptide (BNP) plasma concentration be useful to predict fluid responsiveness [corrected] in critically ill patients with acute circulatory failure?

BACKGROUND AND OBJECTIVES

As B-type Natriuretic Peptide (BNP) is a marker of ventricular wall stress, the present study was aimed at determining whether plasma BNP concentration could predict fluid responsiveness in critically ill patients with acute circulatory failure.

METHODS

This prospective and non randomized interventional study included 33 sedated, mechanically ventilated patients, with acute circulatory failure requiring cardiac output measurement and fluid challenge. Plasma BNP concentration was measured before and after fluid challenge (250 to 500 ml with infusion rate=999 ml/h). An increase in stroke index (SI) greater than or equal to 15% allowed separation of responders from nonresponders. Receiver operating characteristic (ROC) curves were generated for BNP and compared to that of central venous pressure (CVP) that is routinely considered as a marker of cardiac preload.

RESULTS

Among 33 patients, there were 24 responders. At baseline, BNP plasma values were less in responders (328 [35-1190] pg/ml versus 535 [223-5000] pg/ml, p<0.03). The area under the ROC curves was 0.74+/-0.11, that was similar to the area under the ROC curve for CVP (0.77+/-0.10). The best cut-off value of plasma BNP level for predicting fluid responsiveness was 193 pg/ml (sensitivity: 38%, specificity: 100%, positive predictive value: 100%, negative predictive value: 38%, accuracy: 55%). Fluid challenge did not increase plasma BNP concentrations in responders and nonresponders.

CONCLUSION

In critically ill patients with acute circulatory failure, BNP does not accurately predict fluid responsiveness.

[General practitioners' and intensivists' relationships: intensivists' point of view from eight French southern regional areas]

OBJECTIVES

Assessment of relationship between general practitioners and intensivists.

STUDY DESIGN

Intensivists were questioned by phone from June 14th to September 28th 2004.

METHODS

245 out of 264 intensivists from 8 French Southern regional areas were questioned concerning their relationship with critically ill patients' general practitioner.

RESULTS

Patients were mainly admitted into Intensive care Unit (ICU) from the Emergency Department (55%). An information letter from the general practitioner was reported for 20% of admitted patients but 50% of these letters was assumed as not informative. The informations concerning the patient's medical history, therapies, and disease leading to admission and the patient's status were assessed with 6.5, 7.0, 6.0 and 2.0, respectively (maximal note=10). The intensivists contacted the general practitioner for 30% of admitted patients. During the stay in ICU, 33% general practitioners were reported to request informations by phone or visit in ICU. When the stay in ICU was>10 days, the general practitioner was nearly never regularly informed about patient's status. When the patient was discharged from the ICU, 80% of intensivists used an exhaustive typed report to inform the general practitioner. The overall relationship between the general practitioner and the intensivist was assessed as 5.5/10. Insufficient information in the general practitioner's letter at admission, the lack of request for information during the stay in ICU, the lack of contact with the general practitioner by the intensivist and an intensivist's age between 46 and 55 were associated with a relationship assessment<4/10).

Toxicité systémique à la mépivacaïne après un bloc axillaire chez un patient insuffisant rénal chronique

As onset time and duration of sensory block are intermediate, mepivacaine is widely used for regional anaesthesia. Few reports of systemic adverse effects are available following nerve blockade with mepivacaine. We report the case of a 54-year-old patient suffering from terminal renal failure who needs the confection of an arteriovenous shunt under axillary brachial plexus block. At completion of the injection of 25 ml (375 mg) of 1.5% mepivacaine the patient presented dysarthria, mental confusion followed by a loss of verbal contact and agitation, but no convulsion or cardiac dysrythmia. The patient received midazolam and surgery was planned the following day under general anaesthesia. Plasma mepivacaine concentration at time of neurological signs was measured at 5.1 microg/ml. Prevention and treatment of systemic toxic effects after regional anaesthesia are discussed.

Spasticité : intérêt du testing par anesthésie locorégionale et blocs thérapeutiques

Peripheral nerve blockade is one of the therapeutic possibilities to treat spasticity of various muscles. Percutaneous nerve stimulation allows accurate location of nerves and neurolysis can be performed using intraneural injection of 65% ethanol or 5 to 12% phenol. Spastic contraction of various muscle groups is a common source of pain and disability which prevents from having efficient rehabilitation. Test-blocks as well as neurolytic blocks are possible in most of motor nerves of the upper and lower limbs and main indications are spastic sequelae of stroke and spinal trauma but also of multiple sclerosis, cerebral palsy and chronic coma. The use of percutaneous nerve stimulation allows accurate location and four nerves are more frequently treated: pectoral nerve loop, median, obturator and tibial nerves. In patients with spasticity of the adductor thigh muscles, nerve blocks are performed via a combined approach using fluoroscopy and nerve stimulation to identify the obturator nerve. No complications occurred and minor side effects are transient painful phenomena during injection. These approaches proved to be accurate, fast, simple, highly successful and reproducible. Percutaneous neurolytic procedures should be done as early as possible, as soon as spasticity becomes painful and disabling in patients with neurological sequelae of stroke, head trauma or any lesion of the motor neuron.

Surdosage en morphine par cumul d’erreurs provoquant un dysfonctionnement d’une pompe d’analgésie

We report the case of a 67-year-female patient treated with a postoperative patient controlled analgesia using an Abbott Gemstar pump for after nephrectomy. In the postanaesthesia care unit, fifteen minutes after connecting with of the pump (which bag contained 100 mg of morphine) to the patient, respiratory arrest occurred. A morphine overdose was caused by uncontrolled delivery of the entire bag contents by free flowing due only to gravity. The patient was resuscitated immediately, and had uneventful recovery. This incident was the result of multiple misuse: one misconnection of the tubing between morphine bag and the patient thus shunting the antisiphon valve, and two an improper secured PCA cassette in an open position not detected by the pump. The tubing of these pumps and the software were subsequently modified by Abbott, which should reduce the risk of recurring incident. This accident points out that vigilance must remain rigorous in spite of widespread routine use of PCA.

Chronobiology of labour pain perception: an observational study

BACKGROUND

Circadian variation may affect many biological and pharmacological phenomena.

METHODS

To assess circadian variations in labour pain perception, 222 consecutive nulliparous women with uncomplicated pregnancy, spontaneous labour, cervical dilatation (3-5 cm), ruptured membranes and normal fetal heart rate tracings were studied. Visual analogue pain scores (VAPS) were analysed and divided into four periods: night (1:01 a.m. to 7:00 a.m.), morning (7:01 a.m. to 1:00 p.m.), afternoon (1:01 p.m. to 7:00 p.m.) and evening (7:01 p.m. to 1:00 a.m.). VAPS were also compared between daytime (morning+afternoon) and nocturnal (evening+night) periods.

RESULTS

Daytime mean VAPS were lower than nocturnal scores [75.6 (15.1) vs 85.7 (14.1), P<0.0001]. VAPS were lower in the morning than in the afternoon, evening and night periods (anova, P<0.0001).

CONCLUSION

Labour pain perception appears to be chronobiological, and this might be taken into account when enrolling parturients in studies designed to assess or treat labour pain.

Effets hémodynamiques du sérum salé hypertonique au cours du choc septique et du sepsis sévère

OBJECTIVE

Assessment of haemodynamic effects of 250 ml hypertonic saline 7.5% (HS) perfusion in critically ill patients with severe sepsis or septic shock.

STUDY DESIGN

Observational study.

PATIENTS

Twelve mechanically ventilated patients with severe sepsis or septic shock requiring a pulmonary artery catheter and volume loading.

INTERVENTION

Two hundred and fifty millilitres HS were given over 15 min. Were measured: heart rate (HR), mean arterial pressure (MAP) and pulmonary artery pressure (MPAP), pulmonary capillary wedge pressure (PCWP), right atrial pressure (RAP), cardiac index (CI), indexed systemic vascular resistance (ISVR), indexed pulmonary vascular resistance (IPVR), plasma sodium, chloride, protein and haemoglobin concentrations and arterial blood lactate. Studied parameters were assessed at baseline (T(0)) and 5 (T(0)) and 105 min (T(120)) after the end of HS infusion.

RESULTS

MAP, HR and RAP were not altered. HS increased PAPM (25 +/- 5-30 +/- 6 mmHg), PCWP (13 +/- 3-18 +/- 4 mmHg) and CI (3.5 +/- 1.2-4.6 +/- 1.1 l/min per m(2)) at T(20) (P < 0.05). ISVR and IPVR were decreased at T(20). Protein and haemoglobin were decreased at T(20). Sodium and chloride were increased at T(20) (from 136 +/- 4 to 147 +/- 4 and from 110 +/- 6 to 123 +/- 6 mmol/l, respectively, P < 0.01) and T(120).

CONCLUSION

In patients with severe sepsis or septic shock, 250 ml HS transiently (<120 min) increases CI and PCWP and induces an increase in sodium and chloride concentrations.

Temperature measurement in intensive care patients: comparison of urinary bladder, oesophageal, rectal, axillary, and inguinal methods versus pulmonary artery core method

OBJECTIVE

Comparisons of urinary bladder, oesophageal, rectal, axillary, and inguinal temperatures versus pulmonary artery temperature.

DESIGN

Prospective cohort study.

SETTING

Intensive Care Unit of a University-Hospital.

PATIENTS

Forty-two intensive care patients requiring a pulmonary artery catheter (PAC).

INTERVENTION

Patients requiring PAC and without oesophageal, urinary bladder, and/or rectal disease or recent surgery were included in the study. Temperature was simultaneously monitored with PAC, urinary, oesophageal, and rectal electronic thermometers and with axillary and inguinal gallium-in-glass thermometers. Comparisons used a Bland and Altman method.

MEASUREMENTS AND MAIN RESULTS

The pulmonary arterial temperature ranged from 33.7 degrees C to 40.2 degrees C. Urinary bladder temperature was assessed in the last 22 patients. A total of 529 temperature measurement comparisons were carried out (252 comparisons of esophageal, rectal, inguinal, axillary, and pulmonary artery temperature measurements in the first 20 patients, and 277 comparisons with overall methods in the last patients). Nine to 18 temperature measurement comparisons were carried out per patient (median = 13). The mean differences between pulmonary artery temperatures and those of the different methods studied were: oesophageal (0.11+/-0.30 degrees C), rectal (-0.07+/-0.40 degrees C), axillary (0.27+/-0.45 degrees C), inguinal (0.17+/-0.48 degrees C), urinary bladder (-0.21+/-0.20 degrees C).

CONCLUSION

In critically ill patients, urinary bladder and oesophageal electronic thermometers are more reliable than the electronic rectal thermometer which is better than inguinal and axillary gallium-in-glass thermometers to measure core temperature.

Risk factors of failure and immediate complication of subclavian vein catheterization in critically ill patients

OBJECTIVE

To identify the risk factors of failure and immediate complication of subclavian vein catheterization (SVC).

DESIGN

Prospective observational study.

SETTING

Surgical critical care unit of a tertiary university hospital.

PATIENTS

Critically ill patients requiring a first SVC.

INTERVENTION

Subclavian vein catheterization was attempted in 707 patients without histories of surgery or radiotherapy in the subclavian area. Failed catheterizations, arterial punctures, pneumothoraces and misplacements of the catheter tip were recorded. Risk factors of failure and immediate complication were isolated among patients' characteristics, procedure parameters (side and number of venipunctures) and the operator's experience using a univariate +/- multivariate analysis.

MEASUREMENTS AND MAIN RESULTS

Five hundred sixty-two SVCs (79.5%) were achieved without adverse events. Among the remaining 145 catheterizations, 67 (9.5%) failures, 55 (7.8%) arterial punctures, 22 (3.1%) pneumothoraces and 30 (4.2%) misplacements of the catheter tip occurred. More than one venipuncture was the only risk factor of failed catheterization [2 venipunctures, odds ratio =7.4 (2.1-26); >2 venipunctures, odds ratio =49.1 (16.8-144.1)]. More than one venipuncture and age 77 years or more were predictive of the occurrence of immediate complications [2 venipunctures, odds ratio =3.6 (1.8-7.0); >2 venipunctures, odds ratio =14 (7.7-25.3); age >or=77, odds ratio =1.8 (1.0-3.1)]. The operator's training was not predictive of failed catheterization or immediate complication.

CONCLUSION

For SVC, more than one venipuncture is predictive of failed catheterization and immediate complication. Age 77 years or more was predictive of immediate complications.

Pharmacodynamics and atracurium and laudanosine concentrations during a fixed continuous infusion of atracurium in mechanically ventilated patients with acute respiratory distress syndrome

The present study was designed to assess the pharmacodynamics and the plasma levels of atracurium and laudanosine found during a 72-hour fixed rate infusion of atracurium in acute respiratory distress syndrome patients without renal or liver failure. Nine sedated and mechanically ventilated acute respiratory distress syndrome patients without renal or liver failure were paralysed with a bolus of atracurium (1 mg x kg(-1)) followed by a 72-hour continuous infusion (1 mg x kg(-1) x h(-1)). The count of train-of-four (TOF) and TOF ratio were monitored by an accelerograph until full neuromuscular recovery (T4/T1 > or = 0.7). Atracurium and laudanosine concentrations were measured from the onset to four days after cessation of the infusion. An electroencephalogram was recorded daily. Analysis showed that TOF count was always < or = 3 until cessation of the infusion. Following cessation, neuromuscular recovery occurred between 31 and 96 minutes (median value = 45 min). The highest atracurium and laudanosine concentrations ranged from 3.3 to 5.8 microg x ml(-1) and from 3 to 20 microg x ml(-1) respectively. In four patients with renal impairment, the highest laudanosine concentration was > 10 microg x ml(-1). No seizure was recorded. A fixed infusion rate of atracurium in acute respiratory distress syndrome patients provided an effective muscle paralysis with a rapid neuromuscular recovery but can lead to accumulation of laudanosine in patients with renal impairment.

The comparative electrophysiologic and hemodynamic effects of a large dose of ropivacaine and bupivacaine in anesthetized and ventilated piglets

Ropivacaine is less potent and less toxic than bupivacaine. We administered these two local anesthetics in a cardiac electrophysiologic model of sodium thiopental-anesthetized and ventilated piglets. After assessing the stability of the model, bupivacaine (4 mg/kg) and ropivacaine (6 mg/kg) were given IV in two groups (n = 7) of piglets. No alteration in biological variables was reported throughout the study. Bupivacaine and ropivacaine similarly decreased mean aortic pressure from 99 +/- 22 to 49 +/- 31 mm Hg and from 87 +/- 17 to 58 +/- 28 mm Hg, respectively, and decreased the peak of the first derivative of left ventricular pressure from 1979 +/- 95 to 689 +/- 482 mm Hg/s and from 1963 +/- 92 to 744 +/- 403 mm Hg/s, respectively. Left ventricular end-diastolic pressure was similarly increased from 6 +/- 5 to 9 +/- 5 mm Hg and from 6 +/- 4 to 12 +/- 4 mm Hg, respectively. Bupivacaine and ropivacaine similarly lengthened the cardiac cycle length (R-R; from 479 +/- 139 to 706 +/- 228 ms and from 451 +/- 87 to 666 +/- 194 ms, respectively), atria His (from 71 +/- 15 to 113 +/- 53 ms and from 64 +/- 6 to 86 +/- 10 ms, respectively), and QTc (QTc = QT x R-R(-0.5), Bazett formula; from 380 +/- 71 to 502 +/- 86 ms and from 361 +/- 33 to 440 +/- 56 ms, respectively) intervals. Bupivacaine altered to a greater extent the PQ (the onset of the P wave to the Q wave of the QRS complex) (from 97 +/- 20 to 211 +/- 60 ms versus from 91 +/- 8 to 145 +/- 38 ms, P < 0.05), QRS (from 58 +/- 3 to 149 +/- 34 ms versus from 60 +/- 5 to 101 +/- 17 ms, P < 0.05), and His ventricle interval (from 25 +/- 4 to 105 +/- 30 ms vs from 25 +/- 4 to 60 +/- 30 ms, P < 0.05) than ropivacaine. A 6 mg/kg ropivacaine dose induced similar hemodynamic alterations as 4 mg/kg bupivacaine. However, bupivacaine altered the variables of ventricular conduction (QRS and His ventricle) to a greater extent.

IMPLICATIONS

A 6 mg/kg ropivacaine dose induced similar hemodynamic alterations as 4 mg/kg bupivacaine. However, bupivacaine altered the variables of ventricular conduction (QRS and His ventricle) to a greater extent.

The continuous femoral nerve block catheter for postoperative analgesia: bacterial colonization, infectious rate and adverse effects

We investigated the incidence of bacterial and vascular or neurological complications resulting from femoral nerve catheters used for postoperative analgesia. Patients requiring continuous femoral blockade were consecutively included. Using surgical aseptic procedure, 211 femoral nerve catheters were placed (short-beveled insulated needle, peripheral nerve stimulator). After 48 h, each catheter was removed and semiquantitative bacteriological cultures were performed on each distal catheter tip. Postoperative analgesia and antibiotics were standardized. All complications during the insertion of the catheters and postoperatively (after 48 h and 6 wk) were noted. Few initial complications with no immediate or delayed complications were noted (20 difficult insertions, 3 impossible injections, 3 ineffective catheters, and 12 vascular punctures). After 48 h, 208 catheters were analyzed; 57% had positive bacterial colonization (with a single organism in 53%). The most frequent organisms were Staphylococcus epidermidis (71%), Enterococcus (10%), and Klebsiella (4%). Neither cellulitis nor abscess occurred. Three transitory bacteremias likely related to the catheter occurred. After 6 wk, no septic complications were noted. One femoral paresthesia, partially recovered 1 yr later, was noted. We conclude that the risk of bacterial complications is small with femoral nerve catheters, although the rate of colonization is frequent.

IMPLICATIONS

In this prospective study, continuous femoral nerve catheters were effective for postoperative analgesia but had a frequent rate of bacterial catheter colonization. We found no serious infections after short-term (2-day) infusion. Side effects were few, but one nerve injury occurred.

Clinical application of ropivacaine for the lower extremity

Ropivacaine is a new amide local anaesthetic, which is the first commercially available in its category as a pure S-(-) enantiomer. In most recent studies, ropivacaine exhibited a very close pharmacodynamic profile to equipotent doses of bupivacaine. Concentrations of 0.5%, 0.75% and 1% (5, 7.5 and 10 mg/mL, respectively) ropivacaine are used for intraoperative anaesthesia, while the concentration of 0.2% (2 mg/mL) is preferred for postoperative analgesia, either alone or in combination with opioids and/or clonidine. Ropivacaine is responsible for excellent postoperative analgesia following epidural and peripheral perineural injections, using single-shot injections and continuous infusions. Differential sensory/motor block is only apparent at low concentrations (0.2% and less). A significant amount of recent literature focuses on its use for peripheral blocks of the lower limbs, i.e. sciatic and femoral nerve blocks. The primary benefit of ropivacaine is its lower toxicity, mainly lower cardiotoxicity, following accidental intravascular injection. This higher therapeutic index leads to an improved safety profile as compared with potent local anaesthetics such as racemic bupivacaine. For that reason, ropivacaine is a good choice for both intraoperative and postoperative regional anaesthesia and analgesia.

[Pulmonary artery catheterization in the intensive care unit: at what time?]

OBJECTIVES

Recording the time at which the insertion of a pulmonary artery catheter was decided.

STUDY DESIGN

Prospective and descriptive study.

PATIENTS

Critically ill patients in an university hospital.

METHODS

The times at which the insertion of a PAC was decided were recorded. For each pulmonary artery catheterization, immediate complications were recorded (arterial puncture, pneumothorax, ventricular arrhythmia, hard and failed pulmonary artery catheterization).

RESULTS

One hundred and forty-nine patients were included (99 males, age = 63 +/- 15 year, body mass index = 25 +/- 6 kg.m-2, median Apache II score = 16). One hundred and sixty-five PAC insertions were decided (16 patients requiring two PACs). Nine arterial punctures, two pneumothoraces, 42 ventricular arrhythmias, 32 hard and eight failed pulmonary artery catheterizations occurred. Thirty-four PAC insertions were decided between 9 and 10 am whereas = 3 PAC insertions per hour were decided between 1 and 9 am.

CONCLUSION

The rate of decision of PAC insertion are decreased during the second half of the night (1 to 9 AM).

Peribulbar versus retrobulbar anesthesia for ophthalmic surgery: an anatomical comparison of extraconal and intraconal injections

BACKGROUND

Peribulbar and retrobulbar anesthesia have long been opposed on the basis of the existence of an intermuscular membrane, which is supposed to separate the intraconal from the extraconal spaces in a water-tight fashion. A local anesthetic injected outside the cone should spread through this septum to reach the nerves to be blocked. The existence of this septum is questioned. The aim of this study was to compare the spread of a colored latex dye injected intraconally or extraconally to simulate both retrobulbar and peribulbar anesthesia.

METHODS

The authors used 10 heads from human cadavers. For each head, one eye was injected intraconally, and the other eye was injected extraconally. The heads were then frozen and sectioned into thin slices following various planes. They were then photographed and observed.

RESULTS

There was no evidence of the existence of an intermuscular septum separating the intraconal and extraconal spaces. Those two spaces appeared to be part of a common spreading space, the corpus adiposum of the orbit.

CONCLUSIONS

These results are in accord with the fact that clinical studies were not able to clearly demonstrate that retrobulbar anesthesia is more efficient than peribulbar anesthesia. On the basis of a similar clinical efficacy of the two techniques as a result of similar spreading of the local anesthetic injected, and a potentially higher risk of introducing the needle into the muscular cone, the authors recommend replacing retrobulbar anesthesia with peribulbar anesthesia.

Caruncle single injection episcleral (Sub-tenon) anesthesia for cataract surgery: mepivacaine versus a lidocaine-bupivacaine mixture

We compared the quality of anesthesia provided by mepivacaine 2% or a mixture of lidocaine 2%-bupivacaine 0.5%, both with hyaluronidase, in caruncle single-injection episcleral (sub-Tenon) anesthesia. Sixty patients undergoing cataract surgery were included in this randomized, double-blinded study. The time to the onset of blockade, maximal akinesia, need for supplemental injection, and time to recovery were recorded. With mepivacaine, the time to onset was slightly shorter, and the akinesia score higher, than with the mixture. Although statistically significant, these differences are small. With mepivacaine, the time to recovery was shorter. We conclude that the reproducible short duration of the block may be an advantage in outpatient surgery.

IMPLICATIONS

We compared the classic mixture of lidocaine 2% plus bupivacaine 0.5% to mepivacaine 2% for caruncle episcleral (sub-Tenon) anesthesia for cataract surgery. Mepivacaine provided a more efficient block with a quicker onset and a quicker recovery. However, these differences were very small and were of little clinical interest.

Medial canthus episcleral (sub-Tenon) anesthesia imaging

Medial canthus single injection periocular anesthesia is an alternative technique to classical regional anesthesia techniques for cataract surgery. The occurrence of a chemosis at the end of this injection has made us question ourselves about the real site of injection. The purpose of this anatomic study was to identify this site with precision, and to describe the spreading of the injected solution. Various volumes of colored liquid latex were injected when using this technique on 10 human orbits. They were deeply frozen and sectioned in thin slices. The site of injection is clearly the episceral (sub-Tenon) space. This is a gliding space through which pass the ciliary nerves supplying the globe sensitivity. This could explain the high quality of the analgesia of the globe. With the larger volumes injected, spreading of the latex was detected in the orbicularis palpebra. This probably explains the good akinesia of the lids obtained without any facial block. Spreading of the latex to the rectus muscles sheaths should explain the good akinesia of the globe, but was only partially proved in this study. We conclude that the medial canthus single injection periocular anesthesia is an episcleral (sub-Tenon) injection which may explain good anesthesia.

CO assessment by suprasternal Doppler in critically ill patients: comparison with thermodilution

OBJECTIVE

Comparison of suprasternal Doppler (SST) and thermodilution (TD) for the measurement of cardiac output (CO) in critically ill patients.

DESIGN

Prospective study.

SETTING

Intensive care unit of a university hospital.

PATIENTS AND PARTICIPANTS

65 consecutive critically ill patients requiring a pulmonary artery catheter.

INTERVENTIONS

Paired CO measurements were made simultaneously using SST and TD by two independent operators. The time to obtain a CO value by SST was measured. Correlation coefficients and the linear regression equation were determined. A Bland and Altman diagram was plotted. A Bland and Altman diagram was also plotted for the level of cardiac index (CI) values (low: CI < 2.5 l min(-1) m(-2); normal: 2.5 < or = CI < or = 4.5 l min(-1) m(-2); high: CI > 4.5 l min(-1) m(-2)).

MEASUREMENTS AND RESULTS

In seven patients SST failed to measure CO. In the remaining 58 patients 314 paired CO measurements were performed. The mean time to measure CO by SST was 73 +/- 45 s. The equation of linear regression was: SST(CO) = 0.84 TD(CO) + 1.39. The correlation coefficient was 0.84. The bias between SST and TD was -0.2 +/- 1.4 l min(-1). Biases were -0.23 +/- 0.50, -0.20 +/- 0.68, and 0.25 +/- 0.92 l min(-1) m(-2) for low, normal, and high levels of CI, respectively.

CONCLUSION

SST does not accurately measure CO but allows a rapid assessment of CI level in critically ill patients.

Ophthalmic regional anesthesia: medial canthus episcleral (sub-tenon) anesthesia is more efficient than peribulbar anesthesia: A double-blind randomized study

BACKGROUND

Regional anesthesia and especially peribulbar anesthesia commonly is used for cataract surgery. Failure rates and need for reinjection remains high, however, with peribulbar anesthesia. Single-injection high-volume medial canthus episcleral (sub-Tenon's) anesthesia has proven to be an efficient and safe alternative to peribulbar anesthesia.

METHODS

The authors, in a blind study, compared the effectiveness of both techniques in 66 patients randomly assigned to episcleral anesthesia or single-injection peribulbar anesthesia. Motor blockade (akinesia) was used as the main index of anesthesia effectiveness. It was assessed using an 18-point scale (0-3 for each of the four directions of the gaze, lid opening, and lid closing, the total being from 0 = normal mobility to 18 = no movement at all). This score was compared between the groups 1, 5, 10, and 15 min after injection and at the end of the surgical procedures. Time to onset of the blockade also was compared between the two groups, as was the incidence of incomplete blockade with a need for supplemental injection and the satisfaction of the surgeon, patient, and anesthesiologist.

RESULTS

Episcleral anesthesia provided a quicker onset of anesthesia, a better akinesia score, and a lower rate of incomplete blockade necessitating reinjection (0 vs. 39%; P < 0.0001) than peribulbar anesthesia. Even after supplemental injection, peribulbar anesthesia had a lower akinesia score than did episcleral anesthesia. Peribulbar anesthesia began to wear off during surgery, whereas episcleral anesthesia did not.

CONCLUSION

Medial canthus single-injection episcleral anesthesia is a suitable alternative to peribulbar anesthesia. It provides better akinesia, with a quicker onset and more constancy in effectiveness.

Effects of halothane and enflurane on ventricular conduction, refractoriness, and wavelength: a concentration-response study in isolated hearts

BACKGROUND

Effects of halothane and enflurane on ventricular conduction, anisotropy, duration and dispersion of refractory periods, and wavelengths were studied, and putative antiarrhythmic or arrhythmogenic properties on ventricles were discussed.

METHODS

High-resolution epicardial mapping system was used to study the effects of 1, 3, and 5 vol% halothane and enflurane in 30 isolated rabbit hearts. Ten hearts were kept intact to study the effects on spontaneous sinus cycle length (RR interval), perfusion pressure, and the occurrence of spontaneous dysrhythmias. In 20 other hearts, a thin epicardial layer was obtained (frozen hearts) to study ventricular conduction velocity, ventricular effective refractory period (VERP in four sites) and wavelengths.

RESULTS

Halothane induced a concentration-dependent lengthening of RR interval, whereas enflurane did not. Both agents slowed longitudinal and transverse ventricular conduction velocity with no anisotropic change. Ventricular effective refractory period was prolonged at 1 vol% and was shortened at higher concentrations, with no significant increase in dispersion. Ventricular longitudinal and transverse wavelengths decreased in a concentration-dependent manner. Although changes in wavelengths could express proarrhythmic effects of volatile anesthetics, no arrhythmia occurred in spontaneously beating hearts or in frozen hearts.

CONCLUSIONS

The ventricular electrophysiologic effects of halothane and enflurane were slight, suggesting that both agents are unable per se to induce functional conduction block and therefore reentrant ventricular arrhythmias.

Management of reflex sympathetic dystrophy

Reflex sympathetic dystrophy (RSD) is currently defined as CRPS type I (complex regional pain syndrome). Due to the lack of comprehensive understanding of underlying pathophysiological mechanisms, a wide variety of therapeutic approaches are proposed, all of them being of unpredictable and variable efficacy. This is also due to the lack of controlled studies and randomized therapeutic trials. Most of the so-called "efficient" treatments are in fact based on anecdotal case reports and/or uncontrolled studies with small number of cases. Sympathetic blocks and active physiotherapy are, for many authors, the cornerstones of the efficient management. The role of prevention must be strongly emphasized, focusing, if RSD occurs following surgery, on the importance of pre- and postoperative efficient analgesia.

Medial canthus single-injection episcleral (sub-tenon anesthesia): computed tomography imaging

Single-injection medial canthus periocular anesthesia is a promising regional anesthesia technique for ophthalmic surgery. The purpose of this computed tomography (CT) study was to confirm that this technique is an episcleral injection and to explain why it provides a good akinesia of the globe. Four fresh nonpreserved cadavers (eight eyes) were injected with fractioned various volumes of a contrast media using a previously described technique. For each injection and each eye, CT scans were performed in three planes of the space, and the site and spread of the injection was observed. We confirm that single-injection medial canthus periocular anesthesia is, in fact, an episcleral anesthesia, which explains the good sensory block of the globe. When larger volumes are injected, the contrast media spreads to the lids and extraocular muscle sheaths. We believe that this may explain why this technique provides good sensory and motor block of the globe and eyelids. This technique is a promising alternative to both retro- and peribulbar anesthesia.

IMPLICATIONS

We describe medial canthus single-injection periocular anesthesia by a computed tomography injection study in eight human cadaver eyes. It was confirmed to be an episcleral injection. Akinesia of the eyeball is provided by spreading of the local anesthetic solution from the episcleral space to the rectus muscle sheaths.