Canadian Journal of Anesthesia/Journal canadien d anesthésie

Carli, F.; Klubien, K.

doi: 10.1007/bf03012938pmid: 10349918

Kahn, Larry; Baxter, Frederick J.; Dauphin, Alezandre; Goldsmith, Charles; Jackson, Paul A.; McChesney, James; Miller, John D.; Takeuchi, H. Lawrence; Young, James E. M.

doi: 10.1007/bf03012939pmid: 10349919

PurposeTo compare thoracic epidural analgesia (TEA) using a bupivacaine/fentanyl mixture and lumbar epidural analgesia (LEA) with morphine, in respect to the time to extubation and the quality of post-operative analgesia, in patients having thoracoabdominal esophagectomy.MethodsTwenty two patients scheduled for elective thoracoabdominal esophagectomy were randomized to TEA or LEA. Postoperatively, the TEA group received Patient Controlled Epidural Analgesia (PCEA) with bupivacaine 0.125% and 5 μg·mlB1 fentanyl, and the LEA group received PCEA with 0.2 μg·mlB1 morphine. A blinded observer assessed criteria for tracheal extubation and the time of tracheal extubation was recorded. Early extubation was defined as tracheal extubation within four hours postoperatively. Visual analogue pain scores at rest (Static Visual Analogue Pain Scores, SVAPS) and with movement (Dynamic Visual Analogue Pain Scores, DVAPS) were recorded at 1, 6, 12, 18 and 24 hr post-extubation. Failure of the epidural protocol (FEP) was defined as a request for additional analgesia.ResultsTracheal extubation was achieved in 70% of the LEA and 100% of the TEA at four hours postoperatively (P=NS). However, the TEA group achieved earlier extubation times when assessed with log rank testing (P = 0.01). By six hours post-extubation FEP had occurred in 50% of the LEA group but in none of the TEA group (P = 0.01). Mean SVAPS and DVAPS were lower in the TEA than in the LEA group at all measured times (P < 0.01).ConclusionThis study has demonstrated superior pain control in patients undergoing thoraco-abdominal esophagectomy treated with TEA than with LEA, particularly for pain with movement. Tracheal extubation occurred earlier in the TEA group, but this difference was not significant at four hours postoperatively.

Fellahi, Jean-Luc; Valtier, Bruno; Beauchet, Alain; Bourdarias, Jean-Pierre; Jardin, François

doi: 10.1007/bf03012940pmid: 10349920

PurposeTo compare the hemodynamic effects of medical antishock trousers (MAST) inflation in mechanically ventilated patients with normal and poor left ventricular function.MethodsTwelve patients requiring respiratory support were divided into two groups according to baseline transesophageal echocardiography (TEE) measurements: normal left ventricular dimensions and fractional area of contraction (FAC=61 ± 5%) (n=7) and dilated cardiomyopathy with reduced FAC (21 ± 1%) (n=5). All patients were studied when two successive levels of load (mild load by inflation of the leg compartment of MAST at 50 cmH2O and high load by adding the abdominal compartment of MAST inflated at 30 cmH2O) were applied. Global left ventricular systolic function was assessed on the TEE transgastric short-axis view. End-systolic wall stress (ESWS) was used as an indicator of left ventricular afterload.ResultsTotal respiratory, lung and chest wall compliances were reduced by 48%, 51% and 27% respectively at the high load level (P < 0.05). Whereas no hemodynamic changes occurred at mild load, the high load level produced an increase in left ventricular afterload as evidenced by concomitant increases in diastolic arterial blood pressure (66 ± 6 to 79 ± 6 mmHg,P < 0.05) and ESWS (69 ± 12 to 74 ± 12 Kdyn·cm−2·m−2,P < 0.05). In patients with dilated cardiomyopathy, this increase in afterload impaired the left ventricular systolic function and end-systolic area increased (19.0 ± 2.5 to 21.4 ± 2.9 cm2·m−2,P < 0.05) while FAC decreased (22 ± 2 to 16 ± 2%,P < 0.05). Left ventricular end-diastolic area remained unchanged during the study in both groups.ConclusionMAST inflation impairs respiratory mechanics and global left ventricular systolic function in cardiac patients without changes in left ventricular preload.

Ahmed, Ashraf Abdel Kader; Kumagai, Masato; Otake, Tomoko; Kurata, Yutaka; Amaki, Yoshikiyo

doi: 10.1007/bf03012941pmid: 10349921

PurposeTo determine the effect of sevoflurane exposure time on the duration of vecuronium neuromuscular blockade.MethodsIn 40 adult patients anesthesia was induced with 1.5–2 mg·kg−1 propofol and 3–5 μg·kg−1 fentanyl and the trachea was intubated without the aid of muscle relaxant. Patients were randomized into four groups of 10. In group 1, 0.05 mg·kg−1 vecuronium was administered with N2O and anesthesia was maintained by propofol infusion and fentanyl. Vecuronium was administered with sevoflurane 2% in 30 patients, commencing at the same time (group 2) and at 30, and 60 min after sevoflurane (groups 3, 4). Adductor pollicis force of contraction to train-of-four ulnar nerve stimulation was recorded. Times from vecuronium injection to 95%, maximal block, and recovery times to 25% recovery were recorded.ResultsThere were no differences in times to 95% and maximal block in the four groups. Recovery times were longer in groups 3 and 4 than in groups 2 and 1 (P < 0.01). Times to 5% recovery were 15.0 ± 3.7, 17.8 ± 4.8, 28.2 ± 9.9, and 29.5 ± 9.5, and to 25% recovery were 22.3 ± 5.2, 27.2 ± 6.4, 42.3 ± 16.3, and 50.5 ± 16.4 in groups 1, 2, 3, and 4 respectively. No differences were found between group 1 and group 2 nor between group 3 and group 4.ConclusionSevoflurane produced time-dependent potentiation of vecuronium. After 30 min exposure, 25% recovery was prolonged by 89% and after 60 min by more than 100% compared with the control group.ObjectifDéterminer l’effet du temps d’exposition au sévoflurane sur la durée du blocage neuromusculaire avec du vécuronium.MéthodeOn a induit l’anesthésie avec 1,5–2 mg·kg−1 de propofol et 3–5 μg·kg−1 de fentanyl chez 40 patients adultes et on a procédé à l’intubation endotrachéale sans myorelaxant. Les patients ont été répartis en quatre groupes de 10. Dans le groupe 1, on a administré 0,05 mg·kg−1 de vécuronium avec N2O et on a maintenu l’anesthésie avec une perfusion de propofol et de fentanyl. Chez 30 patients, le vécuronium a été administré avec le sévoflurane 2 %, en même temps aux patients du groupe 2, mais 30 et 60 min après le sévoflurane à ceux des groupes 3 et 4. La force de contraction de l’adducteur du pouce à la stimulation en train-de-quatre du nerf cubital a été notée. Le temps nécessaire pour que le vécuronium injecté produise 95 % du bloc, puis le bloc maximal, et le temps nécessaire pour atteindre une récupération de 25 %, ont été enregistrés.RésultatsII n’y a pas eu de différence de temps intergroupe pour produire 95 % du bloc, ni pour le bloc maximal. La récupération s’est prolongée dans les groupes 3 et 4 comparés aux groupes 2 et 1 (P < 0,01). Le temps nécessaire pour atteindre une récupération de 5 % ont été de 15,0 ± 3,7, 17,8 ± 4,8, 28,2 ± 9,9, et de 29,5 ± 9,5, et pour une récupération de 25 % ont été de 22,3 ± 5,2, 27,2 ± 6,4, 42,3 ± 16,3, et de 50,5 ± 16,4 dans les groupes 1, 2, 3, et 4 respectivement. Aucune différence n’a été rapportée entre les groupes 1 et 2, ni entre les groupes 3 et 4.ConclusionLe sévoflurane a produit une potentialisation du vécuronium dépendante du temps. Après 30 min d’exposition le temps nécessaire pour produire une récupération de 25 % s’est accru de 89 % et, après 60 min, de plus de 100 %, si on le compare au temps du groupe témoin.

Takahashi, Shinji; Tanaka, Makoto

doi: 10.1007/bf03012942pmid: 10349922

PurposeTo determine the hemodynamic responses to, and the efficacy of epinephrine-containing epidural test doses, during sevoflurane anesthesia, based on the conventional heart rate (HR) increase ≥20 beats·min−1, the modified HR increase if ≥ 10 beats·min−1, and the systolic blood pressure (SBP) increase 15 mmHg criteria.MethodsOne hundred and twenty patients were randomised to receive sevoflurane 0.5, 1 or 2% end-tidal (n = 40 each) and nitrous oxide 67% in oxygen aftertracheal intubation. Each group of patients was further divided into groups receiving 3 ml lidocaine 1.5% plus 15 μg epinephrine (1:200,000) iv, or 3 ml normal saline (n = 20 each). The HR and SBP were monitored for four minutes after injection of the study drug.ResultsIntravenous injection of the test dose produced HR increases ≥20 beats·min−1 in 18 (90%), 16 (80%) and 14 (70%) patients at sevoflurane concentrations at 0.5, 1 and 2%, respectively, while those receiving saline developed no HR changes. Based on the modified HR criterion, sensitivity, specificity, and positive and negative predictive values were all 100% under sevoflurane concentrations of 0.5 and 1%, but not 2%. On the other hand, all patients in the test dose groups and none in the saline groups developed SBP ≥ 15 mmHg, ensuring 100% efficacy based on the conventional SBP criterion under all sevoflurane concentrations studied. In all patients receiving the intravenous test dose, peak HR occurred 30–45 sec earlier than that of SBP.ConclusionDuring stable sevoflurane anesthesia, peak HR increase ≥ 10 beats·min−1 should be regarded as a positive response with end-tidal sevoflurane concentration ≤ 1%, and peak SBP increase ≥ 15 mmHg is applicable at sevoflurane concentrations between 0.5 and 2%.

Pinsonneault, Céline; Fortier, Joanne; Donati, François

doi: 10.1007/bf03012943pmid: 10349923

PurposeTo review the literature on tracheal and carinal resection and reconstruction, and to report the general approach to these patients, as well as the general guidelines for the safe administration of anesthesia. The airway management is extensively reviewed.SourceArticles obtained from a Medline search (1960 to October 1997; keywords: tracheal surgery, carinal surgery, airway management). Textbook literature including the bibliographies were also consulted.Principal FindingsBenign or malignant tracheal and carinal pathology causing obstruction can be managed in several ways but resection and reconstruction are the treatment of choice for most patients with tracheal stenosis or tumour. Surgery of the trachea is a special endeavour where the airway is shared by the surgeon and the anesthesiologist. The principal anesthetic consideration is ventilation and oxygenation in the face of an open airway. Ventilation can be managed in different ways, including manual oxygen jet ventilation, high frequency jet ventilation, distal tracheal intubation, spontaneous ventilation, and cardiopulmonary bypass.ConclusionThe management of anesthesia for tracheal surgery presents many challenges to the anesthesiologist. Knowledge of the various techniques for airway management is crucial. Meticulous planning and communication between the anesthesia and surgical teams are mandatory for the safe and successful outcome of surgery for patients undergoing this procedure.

Davies, Sharon

doi: 10.1007/bf03012944pmid: 10349924

PurposeDisseminated intravascular coagulation (DIC) is a well-known complication of an amniotic fluid embolus. However, clinical experience has shown that, in some patients, clinical hemorrhage may be the initial presentation. Mortality in this subset of patients is high. This report describes a patient with a suspected amniotic fluid embolus who survived and in whom the initial presentation was post partum hemorrhage.Clinical FeaturesDuring the post delivery repair of a fourth degree perineal tear a 29 yr old prima gravida was noted to have excessive vaginal bleeding despite a well contracted uterus. Laboratory investigations revealed a decrease in hemoglobin from 126 g·l−1 to 86 g·l−1 and a severe disseminated intravascular coagulopathy (PT 27.5 sec, APPT 149 sec, direct fibrinogen < 0.6 g·l−1, FDP > 640 g·l−1). Treatment included massive blood component therapy and, eventually, total abdominal hysterectomy. The patient subsequently recovered without sequelae. In the absence of any other explanation, the coagulopathy was considered to be secondary to amniotic fluid embolus.ConclusionAmniotic fluid embolus remains an important cause of maternal mortality. Clinical reports, reviews of the literature, and the development of the national registry have all contributed to our understanding of this syndrome. Contrary to earlier beliefs, not all patients present with sudden cardiorespiratory collapse. As the present case illustrates, a less common presentation is the development of an isolated DIC in the peripartum period without antecedent hemodynamic or respiratory instability. Therefore, anesthesiologists must maintain a high index of suspicion for the disorder in order to facilitate early recognition and treatment.

Grundler, Sabine; Stacey, Mark R. W.

doi: 10.1007/bf03012945pmid: 10349925

PurposeTo report the management of a patient, with unilateral vocal cord paralysis, undergoing thyroplasty, under general anesthesia.Clinical FeaturesA 25-yr-old man developed hoarseness and occasional episodes of pulmonary aspiration, caused by unilateral vocal cord paralysis. He was scheduled for thyroplasty, in an attempt to ease phonation and to decrease or prevent further episodes of pulmonary aspiration. He refused local anesthesia with sedation and it was therefore decided to attempt the procedure under general anesthesia. The paralysed vocal cord was displaced inwards by a wedge inserted through a window in the thyroid cartilage. We assessed the ideal position of the wedge by using a fibreoptic bronchoscope and laryngeal mask airway during general anesthesia, instead of phonation.ConclusionWe describe the successful use of a general anesthetic for a thyroplasty, a procedure normally done under local anesthesia with or without sedation, in a patient who was keen to have surgery, but who refused local anesthesia with sedation.

Coleman, Margaret M.; Bardwaj, Arun; Chan, Vincent V. W. S.

doi: 10.1007/bf03012946pmid: 10349926

PurposeBack pain and sudden loss of consciousness during recovery from spinal anesthesia are rare. Severe pain may raise fears of serious neurological damage and result in inappropriate management. Bladder distention may present in this way and clinicians should be alert to this possibility and communicate this to nursing staff.Clinical featuresA lumbar spinal anesthetic was performed during a volunteer study, using 15 mg hyperbaric bupivacaine in a healthy 31 yr old man. During recovery, five hours later, as the block regressed to the L1–2 level, he complained of acute, severe back pain and briefly lost consciousness secondary to profound bradycardia. Bladder cathetherization yielded 900 mL urine with immediate and complete relief of symptoms.ConclusionSevere pain secondary to bladder overdistention in the presence of neuroaxial blockade may be referred to the thoracolumbar area, mediated by intact sympathetic afferents. As the saccral parasympathetic supply remains paralyzed, there is no subjective sensation of bladder stretching. If untreated, bladder distention can lead to excessive supraspinal parasympathetic outflow resulting in vasovagal syncope.

Ivani, Giorgio; Lampugnani, Elisabetta; De Negri, Pasquale; Lonnqvist, Per-Arne; Broadman, Lynn

doi: 10.1007/bf03012947pmid: 10349927

PurposeTo assess and compare the onset time and duration of neuroblockade obtained after ropivacaine or bupivacaine in infants undergoing major abdominal surgery. We also evaluated the efficacy and safety of employing ropivacaine instead of bupivacaine to provide operative anesthesia and postoperative analgesia.MethodsIn a prospective double blind study 28 infants, aged 1–12 months, undergoing elective major abdominal surgery, were randomly allocated to receive, after induction of general anesthesia, either 0.7 ml· kg−1 bupivacaine 0.25% (group B) or ropivacaine 0.2% (group R) via lumbar epidural block. The onset time, total surgical time and duration of analgesia were recorded.ResultsNo differences were noted in demographic data, hemodynamic variables or duration of surgery. The onset time for sensory blockade was 13.1 min ± 2.1 (group B) and 11.7 ± 2.4 min (group R). The duration of analgesia was 491 ± 291 (group R) and 456 min ± 247 (group B). Eight patients in group B and six in group R needed codeine and acetaminophen rescue on at least one occasion during the 24 hr study period. No major side effects were noted in either groups.ConclusionsIn infants undergoing major abdominal surgery under combined epidural/light general anesthesia, ropivacaine 0.2% produces sensory and motor blockade similar in onset, duration of action and efficacy to that obtained from an equal volume, 0.7 ml· kg−1, of bupivacaine 0.25%.