Biomedical subjects
Publications and source records attributed to D Benhamou.
A case of recurarization in the recovery room is reported. Accumulation of atracurium in the intravenous line led to recurarization after flushing the line in the recovery room. A respiratory arrest with severe desaturation and bradycardia occurred. Circumstances leading to this event and the mechanisms enabling a neuromuscular blockade to occur, following the administration of a small dose of relaxant, are discussed.
Portal triad clamping (PTC) reduces venous return of blood to the heart. However, the decrease in cardiac index (CI) is associated with an unexpected increase in mean arterial pressure (MAP) and the 40% increase in systemic vascular resistance is greater than anticipated in compensation for the 10% decrease in CI. We hypothesized that a reflex elicited in the peritoneum accounted for this unanticipated haemodynamic response. Twenty patients undergoing liver resection were allocated randomly to have hepatic pedicle infiltration before PTC with either lidocaine 200 mg or placebo. MAP was recorded, and plasma osmolality and plasma concentrations of vasopressin, epinephrine, norepinephrine, dopamine, renin and endothelin were measured. After PTC, MAP increased significantly in the placebo group but decreased significantly in the lidocaine group. Plasma concentrations of vasopressin, epinephrine and norepinephrine increased significantly in the placebo group. Plasma concentrations of vasopressin decreased significantly in the lidocaine group, while plasma concentrations of epinephrine and norepinephrine were unchanged. A subsequent study in eight patients found that neither haemodynamic nor hormonal changes associated with PTC in the placebo group were altered by administration of lidocaine 200 mg i.m. before PTC.
UNLABELLED: The effect of epidural or spinal epinephrine when added to local anesthetics on spinal cord blood flow (SCBF)are controversial. We evaluated the effects of epidural lidocaine, with or without epinephrine, on spinal cord blood flow in young and adult rabbits receiving 2% plain lidocaine, 2% lidocaine with epinephrine (1:200,000), or saline epidurally. Colored microspheres were injected through the left ventricle 10 min before and 7.5 and 30 min after epidural injection. The organs (brain, heart, kidneys, and the L6-7 segment of the spinal cord) were analyzed for regional blood flow determination. A significant decrease in mean arterial pressure was observed after the administration of lidocaine, with or without epinephrine, in both adult and young animals compared with saline. SCBF did not change over time in adult rabbits. Conversely, a significant decrease in SCBF was observed in the two groups of young rabbits receiving lidocaine. This decrease correlated with the decrease in mean arterial pressure but did not correlate with the use of epinephrine. We conclude that any reduction in blood pressure occurring in pediatric patients receiving a combined epidural-general anesthetic may result in decreased SCBF. IMPLICATIONS: In young rabbits, any decrease in blood pressure was followed by a decrease in spinal cord blood flow, a decrease that did not correlate to the use of epinephrine and was not observed in adult animals. These data suggest that blood pressure should be monitored closely to promptly treat any decrease in blood pressure when combined epidural-general anesthesia is used in children.
UNLABELLED: Aprotinin reduces blood loss in many orthopedic procedures. In posterior lumbar spine fusion, blood loss results primarily from large vein bleeding and also occurs after the wound is closed. Seventy-two patients undergoing posterior lumbar spine fusion were randomly assigned to large-dose aprotinin therapy or placebo. All patients donated three units of packed red blood cells (RBCs) preoperatively. Postoperative blood loss was harvested from the surgical wound in patients undergoing two- and/or three-level fusion for reinfusion. The target hematocrit for RBC transfusion was 26% if tolerated. Total (intraoperative and 24 h postoperative) blood loss, transfusion requirements, and percentage of transfused patients per treatment group were significantly smaller in the aprotinin group than in the placebo group (1935 +/- 873 vs 2809 +/- 973 mL per patient [P = 0.007]; 42 vs 95 packed RBCs per group [P = 0.001]; 40% vs 81% per group [P = 0.02]). Hematological assessments showed an identically significant (a) intraoperative increase in both thrombin-antithrombin III complexes (TAT) and in activated factor XII (XIIa) and (b) decrease in activated factor VII (VIIa), indicating a similar significant effect on coagulation in patients of both groups (P = 0.9 for intergroup comparisons of postoperative VIIa, XIIa, and TAT). Intraoperative activation of fibrinolysis was significantly less pronounced in the aprotinin group than in the placebo group (P < 0.0001 for intergroup comparison of postoperative D-dimer levels). No adverse drug effects (circulatory disturbances, deep venous thrombosis, alteration of serum creatinine) were detected. Although administered intraoperatively, aprotinin treatment dramatically reduced intraoperative and 24-h postoperative blood loss and autologous transfusion requirements but did not change homologous transfusion in posterior lumbar spine fusion. IMPLICATIONS: In our study, aprotinin therapy significantly decreased autologous, but not homologous, transfusion requirements in posterior lumbar spine fusion.
BACKGROUND: Intrathecal neostigmine induces analgesia but also several side effects. Recently, 500 microg neostigmine administered intraarticularly was shown to produce postoperative analgesia without side effects. The authors' goal was to determine whether 500 microg neostigmine added to mepivacaine in axillary plexus block prolongs postoperative analgesia. In addition, they wanted to determine the incidence of side effects in patients undergoing hand surgery. METHODS: Sixty-nine outpatients scheduled for carpal tunnel syndrome repair with axillary plexus block were randomly assigned to one of three groups that received saline solution in the axillary plexus and subcutaneously (group 1), 500 microg neostigmine in the axillary plexus and saline solution subcutaneously (group 2), or saline solution in the axillary plexus and 500 microg neostigmine subcutaneously (group 3). Sensory and motor block in the four hand nerve distributions were assessed every 5 min for 30 min The duration of the sensory and motor blocks were assessed after operation. Side effects were also recorded. RESULTS: Neostigmine had no effect on sensory and motor block in any of the four nerve distributions, nor did it increase the median duration of sensory block (215 min; range, 120-330 min) compared with group 1 (247 min; range, 190-287 min) or group 3 (236 min; range, 160-280 min). Motor block was slightly shorter (P = 0.045) in group 3 (190 min; range, 135-285 min) compared with group 1 (218 min; range, 145257 min) and group 2 (215 min; range, 105-343 min). Gastrointestinal side effects occurred in 30% of patients in both neostigmine groups but not in group 1 (P < 0.05). CONCLUSIONS: This study suggests that 500 microg neostigmine added to mepivacaine in axillary plexus block does not prolong postoperative sensory block, but it does cause a relatively high incidence of side effects. These two findings raise doubts about the use of neostigmine associated with local anesthetics for plexus neural block.
OBJECTIVES: We compared the efficacy of the standard nasal cannula and the demand oxygen delivery system (DODS) during sleep in patients with COPD. SUBJECTS: Twenty patients with moderate or severe COPD were included in the study. METHODS: Four consecutive polysomnographic recordings were performed under the following conditions: DODS powered by compressed air (night 1 [N1]); oxygen delivered with a nasal cannula alone (night 2 [N2]); oxygen delivered through a DODS (night 3 [N3]); and oxygen delivered with nasal cannula alone (night 4 [N4]). Oxygen flow rates with and without DODS were adjusted the day before the first night so that the resulting transcutaneous arterial oxygen saturation (SaO2) was > or = 95%. The following parameters were evaluated each night: apnea-hypopnea index, nocturnal SaO2, total oxygen saving, and several neurophysiologic parameters. RESULTS: The oxygen saving with the DODS was, on average, 60%. All parameters obtained during N2 and N4 (oxygen alone) were identical. The percentage of total recording time spent at SaO2 > or = 95% was comparable between N2 ([mean +/- SD]; 69+/-32%) and N3 (61+/-31%) (difference is not significant [NS]), as was the time spent at SaO2 between 90% and 95% (N2, 29.8+/-31%; N3, 35.9+/-27%; NS) and < 90% (N2, 0.75+/-2.6%; N3, 2.5+/-8.6%; NS). Although the mean response time was not significantly different between N2 and N3, two patients experienced a substantial increase in response time with an SaO2 < 90% on the DODS. The DODS device did not induce any difference in the percentage of time spent in rapid eye movement (REM) sleep (N2, 12.3+/-8.7%; N3, 16.4+/-7.8%; NS) or non-REM sleep (N2, 87.7+/-8.7%; N3, 83.7+/-7.9%; NS). Non-REM distribution in stage 1-2 sleep and in stage 3-4 sleep was comparable between N2 and N3. Similarly, no difference was observed for the sleep efficiency index (N2, 71+/-15%; N3, 69.6+/-14%; NS). Differences between sleep onset latency times were NS. CONCLUSIONS: In a majority of moderate to severe COPD patients, the use of a DODS device does not induce any significant alteration of nocturnal neurophysiologic and ventilatory profiles. However, the presence of nocturnal desaturation in a few patients justifies the need to systematically perform a ventilatory polygraphic recording when prescribing a DODS device.
UNLABELLED: It has not been proven whether one or multiple nerve stimulations and injections provide a higher rate of complete sensory block in both major sciatic nerve sensory distributions below the knee when a popliteal sciatic nerve block is performed using the lateral approach. This prospective, randomized, single-blinded study compared the success rate of the sciatic nerve block using this approach when one or both major components of this nerve (i.e., tibial nerve and common peroneal nerves) are stimulated in 50 patients undergoing foot or ankle surgery. In Group 1 STIM, 24 patients received a single injection of 20 mL of a mixture of 2% lidocaine and 0.5% bupivacaine with 1:200,000 epinephrine after foot inversion had been elicited. In Group 2 STIM (n = 26), 10 mL of the same solution was injected after stimulation of each sciatic nerve component. For patients with complete sensory motor block, there was no difference in onset between groups. However, Group 2 STIM showed a greater success rate compared with the Group 1 STIM (2 STIM: 88% vs 1 STIM :54%; P = 0.007). When two stimulations were used, the onset time of anesthesia in the cutaneous distribution of the common peroneal nerves was shorter than in the tibial nerve (17.5 vs 30 min; P < 0.0001). We conclude that a two-stimulation technique provides a better success rate than a single-injection technique when a popliteal sciatic nerve block is performed using the lateral approach with 20 mL of local anesthetic. IMPLICATIONS: A better success rate is achieved with a double stimulation technique than with a single injection for the sciatic nerve block via the lateral approach at the popliteal fossa when 20 mL of local anesthetics is used.
Physiological respiratory and hormonal changes occurring during pregnancy result in increased oxygen consumption related to fetal growth. The increase in the maternal basal metabolism leads to hyperventilation and increased cardiac output. This explains why pathological respiratory or cardiovascular conditions existing prior to pregnancy can rapidly worsen during the course of the pregnancy. However, even if no cardiorespiratory disease exists prior to pregnancy, an inhalation lung disease, pre-eclampsia or sepsis can lead to pulmonary edema due to the increased plasma volume in the pregnant woman. These different pathological situations as well as infectious lung diseases are discussed here. We examine the evolution of respiratory function during the course of labor, delivery and the post-partum period. In addition, pregnancy also has an effect on chronic respiratory disease, particularly asthma.
PURPOSE: To determine the causes of failure of epidural analgesia during labour and delivery. METHODS: During six months, pregnant patients receiving epidural analgesia and delivering vaginally were studied prospectively. Bupivacaine 0.125% was used for the initial bolus dose and subsequent continuous infusion. Top-ups of the same solution were used for inadequate pain relief assessed using a visual analogue pain score (VAPS) and/or by clinical examination. Inadequate pain relief was defined as the need for > or = 2 top-ups in addition to epidural infusion and failure during delivery as VAPS > or = 30 mm during the expulsion phase. RESULTS: 1009 patients delivered during this period, 596 had epidural analgesia for vaginal delivery of a live infant and data were complete in 456. Inadequate pain relief during labour and during delivery were found in 5.3% and 19.7% of patients. Risk factors of inadequate pain relief included: inadequate analgesic efficacy of the first dose (Odds ratio: 3.5, P = 0.001) and posterior presentation (Odds ratio: 5.6, P = 0.001). Radicular pain during epidural placement was associated with failure during labour (Odds ratio: 3.9, P = 0.05). Duration of epidural analgesia > six hours (Odds ratio: 9.1, P = 0.001) was a risk factor for insufficient pain relief during labour whereas duration of epidural analgesia < one hour was associated with pain during delivery (Odds ratio: 18.3, P = 0.001). CONCLUSION: Several obstetrical and epidural-related factors increase the risk of inadequate epidural analgesia. For some, simple changes of practice pattern may lead to improved pain relief.
INTRODUCTION: Following their use for a few years, the place of new macrolides can be assessed. CURRENT KNOWLEDGE AND KEY POINTS: "New macrolides", ie, roxithromycin, clarithromycin, azithromycin and dirithromycin, are derivated from erythromycin and defined by different pharmacokinetic parameters: longer half time with better oral administration and shorter duration of treatment, better tissue concentrations with reduction of dosages and better tolerance, high cellular concentration with good activity. However, new macrolides and erythromycin do not show major differences in their antibacterial spectrum against usual pyogenic strains. Clinical use of new macrolides extends to opportunistic infections, such as atypical mycobacterial infections or toxoplasmosis, occurring in the course of HIV infection. New macrolides are also recommended for the treatment of Helicobacter pylori-related gastroduodenal ulcer. FUTURE PROSPECTS AND PROJECTS: New macrolides have opened new avenues in the development of anti-infectious strategies. Due to their good efficacy against Chlamydia pneumoniae which is suspected of inducing vascular diseases, the upcoming use of ketolids and the development of their non-antibiotic effects, the future of macrolides is favorable.
Difficult intubation remains one of the major risks in anaesthetic practice. Recently, as other anaesthetic societies, the French Society for Anaesthesia and Intensive Care (SFAR) has produced algorithms for the management of a difficult intubation. New laryngoscopes and blades have been marketed in recent years, however their place in these algorithms remains unclear. In this preliminary study, we compared the laryngoscopic view in 100 consecutive patients during tracheal intubation with the McCoy laryngoscope first in its normal position and after levering the distal part of the blade. All patients were included in Mallampati classes 1 and 2. Among them, 16% were classified as Cormack and Lehane grades 3 or 4 when using the blade in the normal position. These data confirm previous observations showing that the McCoy blade in normal position performs poorly as compared with the Macintosh blade. Conversely the levering of the distal part of the blade significantly decreased the incidence of Cormack and Lehane grades of 3 or 4 (2 versus 16%, P = 0.001). It is concluded that the McCoy blade is not convenient for its routine use in patients not to be at preoperatively known risk of difficult intubation. This blade significantly improves intubating conditions. Defining the exact place of this new blade in difficult intubation algorithms requires further studies.
Pain is a subjective feeling; its assessment is therefore difficult, and no "gold standard" method exists for humans. Major improvements have, however, been made in the last decade by widespread acceptation of the concept of pain evaluation and widespread use on surgical wards. Evaluation by the patient himself is the rule (unless communication is impaired), as assessment of pain by nurses or doctors systematically leads to underestimation (which also occurs with observational scales). Theoretically, pain should be evaluated in its multiple dimensions such as intensity, location, emotional consequences and semiologic correlates. Scales which have been developed to evaluate these dimensions are, however, too complex for widespread and repetitive use in surgical patients. The Mac Gill Pain Questionnaire is therefore only used in the surgical setting for research purposes. Moreover, its scientific accuracy, although often accepted, is poor and in our opinion cannot be accepted as a reference method. Only methods assessing pain intensity can be used in the clinical setting because of their simplicity. The verbal rating scale (VRS), the numerical rating scale (NRS) and the visual analogue scale (VAS) are preferred by an increasing number of groups. Although scientific validation is difficult, VAS seems the most accurate and reproducible scale. Post-operative pain should be assessed several times a day in every patient, at rest and in dynamic conditions (cough, movement) and should focus on present pain rather than on pain in the previous hours. Assessment of pain is essential before quality-assurance programmes can be implemented.
OBJECTIVE: To evaluate the learning of tracheal intubation with a new rigid fibreoptic laryngoscope (UpsherScope). STUDY DESIGN: Open prospective study. PATIENTS: Five investigators used the UpsherScope to intubate the trachea in 164 patients scheduled for gynaecological surgery requiring tracheal intubation. All patients were of physical class ASA I or II and criteria for difficult intubation were negative. METHODS: After muscle relaxation, 120 seconds were allowed to intubate the trachea with the UpsherScope. If intubation had not been achieved by that time, the attempt was considered as a failure and the trachea was intubated using conventional laryngoscopy. RESULTS: The overall success rate with the UpsherScope was 73%. Forty-five tracheas could not be intubated with the device within 120 seconds. The inability to insert the tracheal tube through the vocal cords despite a good view of the larynx (23/45) or the inability to visualise the glottis because of secretions (21/45), were the two main causes of failure. CONCLUSION: The UpsherScope, a new rigid fibreoptic laryngoscope devised for routine and difficult intubation, is robust and allows the view of the tracheal tube passing between the vocal cords. However, in this study the intubation success rate remained low and was not improved by further experience. No benefit was found with the UpsherScope in patients with normal airways. Further studies are necessary to assess its efficiency in cases of difficult intubation.
Epidural analgesia and spinal analgesia are the most effective techniques for relieving labour pain. Basically, local anaesthetics (i.e. bupivacaine) and opioids (i.e. fentanyl or sufentanil), especially when combined, produce excellent analgesia with minimal motor blockade. However, none of these agents is devoid of side-effects and analgesia remains sometimes imperfect, suggesting that new drugs would be welcome. Adrenalin and clonidine act on a2-adrenoceptors in the spinal cord and both have been found to improve analgesia. These two drugs have already been used in many patients and studies because the absence of neurotoxicity has been well documented. Clonidine looks more attractive, although sedation and hypotension limit its use. Other analgesic drugs are promising alternatives but are still at an experimental or very early clinical stage. Neostigmine and ketamine (without preservative) are not neurotoxic while midazolam neurotoxicity is still controversial. Intravenous remifentanil might prove useful when neuraxial analgesia is contraindicated.
We report a case of Streptococcus salivarius meningitis following combined spinal-epidural analgesia for labour. Although rare, bacterial meningitis following combined spinal-epidural anaesthesia is being increasingly described. We review the previously reported cases and discuss the possible aetiological causes and the aseptic precautions likely to reduce the incidence of infectious complications.
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UNLABELLED: Although no guidelines concerning discharge criteria after axillary plexus block are available, many institutions consider recovery of motor function as a critical factor. With the midhumeral approach, the four main nerves of the upper extremity can be blocked separately using a peripheral nerve stimulator. The aim of this double-blind study was to block the radial (R) and musculocutaneous (MC) nerves with lidocaine, and the median (M) and ulnar (U) nerves with bupivacaine to recover motor function of the elbow and wrist more rapidly while maintaining long-lasting postoperative analgesia at the operative site. Patients undergoing surgery for Dupuytren's contracture were randomized into two groups in a double-blind fashion: in the control group (n = 17), each of the four nerves was infiltrated with 10 mL of a mixture of 2% lidocaine and 0.5% bupivacaine, whereas in the selective group (n = 17), the R and MC nerves were blocked with 10 mL of 2% lidocaine each and the M and U nerves were blocked with 10 mL of 0.5% bupivacaine each. Recovery of motor block was significantly faster in the selective group (231 +/- 91 vs 466 +/- 154 min). However, time to first sensation of pain was not different between groups (707 +/- 274 vs 706 +/- 291 min). In conclusion, this new approach at the midhumeral level enables the anesthesiologist to selectively administer local anesthetics on different nerves. IMPLICATIONS: In outpatients undergoing surgery for Dupuytren's contracture, a midhumeral block was used with the musculocutaneous and radial nerves blocked by lidocaine and the median and ulnar nerves blocked with bupivacaine. Recovery of motor function and time to discharge were shorter compared with patients who received the mixture on all four nerves.