Example of cost calculations for an operating room and a post-anaesthesia care unit

OBJECTIVE

The aim of this study was to evaluate the cost of an operating room using data from our hospital. Using an accounting-based method helped us.

METHODS

Over the year 2012, the sum of direct and indirect expenses with cost sharing expenses allowed us to calculate the cost of the operating room (OR) and of the post-anaesthesia care unit (PACU).

RESULTS

The cost of the OR and PACU was €10.8 per minute of time offered. Two thirds of the direct expenses were allocated to surgery and one third to anaesthesia. Indirect expenses were 25% of the direct expenses. The cost of medications and single use medical devises was €111.45 per anaesthesia. The total cost of anaesthesia (taking into account wages and indirect expenses) was €753.14 per anaesthesia as compared to the total cost of the anaesthesia. The part of medications and single use devices for anaesthesia was 14.8% of the total cost.

CONCLUSION

Despite the difficulties facing cost evaluation, this model of calculation, assisted by the cost accounting controller, helped us to have a concrete financial vision. It also shows that a global reflexion is necessary during financial decision-making.

[Prolonged phase II neuromuscular blockade following succinylcholine administration]

Patients who are given a single dose of succinylcholine normally undergo a short-acting depolarizing phase I neuromuscular block but rarely a phase II block. Prolonged neuromuscular blockade occurs after a single dose of succinylcholine in case of genetically determined abnormal plasma butyrylcholinesterase activity. It is mandatory to use monitoring to detect this side effect. We report a case of a patient with abnormal plasma butyrylcholinesterase activity undergoing a six-hour prolonged neuromuscular phase II block, after a single dose of succinylcholine.

[Prolonged residual paralysis after a single intubating dose of rocuronium: an unexpected cause]

Postoperative curarization following a single dose of rocuronium is a known risk quickly diagnosed through the monitoring of neuromuscular blockade. Different etiologies can cause a prolonged block. We report the case of a misdiagnosis of prolonged neuromuscular blockade by a failure in the monitoring system of curarization.

[Perioperative anaesthetic management of an epileptic patient treated with a vagus nerve stimulation]

The vagal nerve stimulation is approved for medically refractory epilepsy and major depression. We report the perioperative management of an epileptic patient with this indwelling device. This observation summarizes the physiologic implications and the specific anaesthetic considerations for procedures with this pre-existing device.

Monitoring neuromuscular block: an update

The first part of this article presents an update of the basic considerations of neuromuscular monitoring. It emphasises the need to assure supramaximal stimulation, to place the stimulating electrodes correctly and to use appropriate sites for nerve stimulation as well as appropriate stimulation patterns. The second part focuses on current developments and ongoing discussion. The authors describe the performance of acceleromyography and the need for initial calibration when using these quantitative devices.

Relationship between procalcitonin values and infection in brain-dead organ donors

BACKGROUND AND AIMS

An association between the inflammatory reactions estimated by several biomarkers and organ dysfunction has been reported in brain-dead organ donors (BDOD). Procalcitonin (PCT), a biomarker of inflammation due to bacterial infection, is increased among BDOD. However, is not known whether infection changes PCT values in BDOD.

MATERIALS AND METHODS

We retrospectively analyzed 82 BDOD including several demographic and clinical parameters, bacterial culture results, antibiotics prescription, and plasma values of PCT measured before organ harvesting. Infection was diagnosed to be either a positive bacterial culture (restricted definition) and/or prescription of antibiotics (extended definition).

RESULTS

The median PCT value was 1.5 (interquartile range [IQR], 0.4 to 6.9; range, 0 to 526 ng/mL; n=82). Thirty-eight (46%) and 24 (29%) patients had PCT values>2 ng/mL and >5 ng/mL, respectively. Median PCT values among infected (1.18; IQR, 0.27 to 6.55 ng/mL) versus noninfected (1.57; IQR, 0.53 to 7.15 ng/mL) BDOD (restricted definition) were not different (P=.36). The area under the receiver operating characteristic curve using PCT to predict infection (restricted definition) was 0.52. Specificity of PCT to predict infection was above 80% at PCT values>9 ng/mL.

CONCLUSION

Our results confirmed PCT values are increased in BDOD, suggesting that this was not related to an infectious cause (whatever definition was used) unless PCT values are high.

Update on neuromuscular pharmacology

Since the introduction of d-tubocurarine into clinical practice, neuromuscular relaxants have been widely used in anaesthesia. Although their clinical use is easy, several points still require further attention and research. There is still a need for a drug with the clinical profile of succinylcholine but fewer unwanted side-effects. A better understanding of the effects of muscle relaxants on different muscles could help in their clinical use during the perioperative period. Much knowledge is needed about residual neuromuscular block and its detection in order to improve the quality of recovery from neuromuscular blockade. If some questions remain to be answered, several recent articles have increased our knowledge and should improve our clinical practice.

Sequential measurements of troponin Ic values in brain-dead patients considered as potential heart donors

It was suggested that a single value of normal or increased plasma cardiac troponin T or I (cTnT or cTnI) concentration could contribute to estimate donor myocardial damage and function in brain-dead patients. In patients with acute coronary syndromes, an initial normal value of troponin must be confirmed several hours later but no such recommendations exist for brain-dead patients. We investigated the relationship between two sequential (6 h interval) measurements of plasma cTnI concentrations in brain-dead patients considered as potential heart donors. The first and the second TnIc values were correlated with an adjusted r2 value of 0.92 (p<0.001). Our results suggest therefore that it is not necessary to repeat the measurements, when the value of plasma cTnI concentration is taken into consideration in the algorithm for cardiac harvesting.

Rupture d'un angiomyolipome rénal lors d'une grossesse

A 40 year-old 2nd gesta pregnant woman (34.5 weeks of amenorhea) was admitted to hospital for abdominal pain and arterial hypotension which were rapidly related to a retroperitoneal haematoma due to left kidney bleeding. Emergency cesarean delivery under general anaesthesia was undertaken because of foetal distress. Exploration of the retroperitonal space after foetal extraction confirmed the presence of a large haematoma and abnormal left renal morphology. The retroperitoneal space was drained without any further intervention. Subsequently, abdominal and thoracic computerised tomographic examination showed bilateral dysplasia of the kidneys and pulmonary cysts consistent with the diagnosis of renal angiomyolipoma and pulmonary lymphangioleiomyomatosis. The case report is of interest because of the circumstances of discovery of the disease and because nephrectomy was not necessary to control the bleeding of the left kidney. Six months after the incident the patient and the child are in good condition.

Inter-patient variability upon induction with sevoflurane estimated by the time to reach predefined end-points of depth of anaesthesia

BACKGROUND AND OBJECTIVES

A difficult issue in anaesthesia is its titration for an individual patient to avoid over- and underdosage. Common practice is to use an initial dose and increase it subsequently if the defined end-point is not reached. This assumes that the end-point is reached after a similar interval of time in all patients given a similar dose. In order to test this hypothesis we measured the time to reach end-points such as loss of consciousness (LOC), a bispectral index (BIS) value of 60, the minimal BIS and the minimal mean arterial pressure (MAP) values.

METHODS

Thirty patients aged 18-60 yr scheduled for general surgery were included in this observational study. After preoxygenation, induction was performed with 6% inspired concentration of sevoflurane in 6 Lmin-1 oxygen using the SiBI connector and the tidal volume technique. Remifentanil was administered when the BIS value was 60 and tracheal intubation was performed 4 min later.

RESULTS

Time (median, minimum-maximum) to LOC, a BIS value of 60, the minimal BIS and MAP values were, respectively, 75 (45-135), 120 (75-270), 300 (120-720) and 450 (120-1200) seconds. The time to the minimal BIS value was significantly (P < 0.05) shorter than the time to reach the minimal MAP value.

CONCLUSIONS

These results demonstrate large inter-patient variability for the time necessary to reach defined end-points of depth of anaesthesia when a similar dose of anaesthetic is given. Measuring the time to reach a predefined BIS value would allow application of nociceptive stimuli only at adequate levels of hypnosis and would facilitate titration.

[Influence of pregnancy on renal angiomyolipoma]

The aim is to perform a literature search on the role of pregnancy in the rupture of renal angiomyolipoma. Articles published from 1952 to 2004 in the Medline database were searched using the keywords renal angiomylipoma and pregnancy. Pathologies associated with angiomylipoma (lymphangioleiomyomatosis and Bourneville tuberous sclerosis) were taken into account. Seventy-two cases of association of renal angiomyolipoma and pregnancy were found, out of which 58 presented a haemorrhage. In only 26% of the cases, renal angiomyolipoma had been documented prior to pregnancy. Clinical presentation was similar to cases occurring among non pregnant women: abdominal pains (88%), hypotension or shock (33%) and hematuria (24%). Average size of the rupture was 11,7 cm. Rupture does not occur solely with the first pregnancy but occurred equally during the first, second and third pregnancy. Average gestation age upon occurrence of haemorrhage was 27 weeks with a minimum at ten weeks. Therapeutic strategies at the time of shock or hypotension were total nephrectomy in 79% of the cases, 7% polar nephrectomy, 7% embolisation followed by nephrectomy and 7% abstention. A causal role of pregnancy in the atraumatic rupture of angiomyolipoma is not clearly defined. Nevertheless, many arguments (whether it be abdominal mechanical pressure, hormonal or histological ones) suggest that a pregnancy could increase the risk of renal angiomyolipoma rupture. These patients should have a medical follow-up period at closer intervals during their pregnancy and the postpartum phase.

Telerobotic-assisted laparoscopic hysterectomy for benign and oncologic pathologies: initial clinical experience with 30 patients

BACKGROUND

Telerobotic-assisted laparoscopic attempts to provide technological solutions to the inherent limitations of traditional laparoscopic surgery. The aim of this study is to report the first experience of two teams concerning telerobotic-assisted laparoscopic hysterectomy for benign and malignant pathologies.

METHODS

This study included 14 patients at the University Hospital Saint Pierre of Brussels (Belgium) and 16 patients at the Cancer Center of Nancy (France) from September 1999 to July 2003.

RESULTS

The indications for surgery were uterine malignant diseases in 12 cases (stade I) (41%), and benign pathologies of the uterus in 18 cases (59%). Five postoperative complications (17%) occurred, none related to the robotic system.

CONCLUSION

Robotic surgery can be safely performed in gynecologic and gynecologic-oncologic surgery with no increase in complication rates. A significant advance is represented by the surgeon's ergonomic improvement.

Anticoagulation péri-opératoire par danaparoïde (Orgaran®) chez un patient ayant un syndrome de Budd-Chiari et une thrombopénie induite par l’héparine

We report a case of Budd-Chiari syndrome revealing a polycythemia vera and complicated by heparin-induced thrombocytopenia. A surgical porto-caval shunt was inserted with danaparoid as anticoagulant during the peri-operative period. The doses of danaparoid were as follows: a continuous intravenous infusion of 200 U/h with a target between 0.5 et 0.8 U/ml antifactor Xa activity during the preoperative period, followed by 100 U/h with a target of 0.3 U/ml during the peroperative period; an increase in doses of danaparoid to 150 and 200 U/h with a target above 0.5 U/ml was used during the postoperative period. This case report is a rare situation of hypercoagulable state, in a surgical context, treated with danaparoid.

Analyse des critères qui participent à la décision de prélèvement cardiaque chez les patients en état de mort encéphalique

OBJECTIVES

The number of cardiac transplantation procedures does not increase because of the lack of donor hearts despite an increase in the number of brain-dead organ donors. The criteria used to select a donor heart are not formally standardized. The aim of the present study was to analyze the criteria that contribute to the selection of a donor heart.

TYPE OF STUDY

Descriptive, retrospective study.

PATIENTS AND METHOD

Clinical parameters, the initial causes that lead to brain death, maximum doses of catecholamines, several biochemical markers of myocardial ischaemia/necrosis as well as several echocardiography criteria were extracted from a prospectively collected database. Univariate and multivariate (logistic regression) analyses were performed with the "harvested heart" as dependent variable and the above-cited independent variables.

RESULTS

One hundred and eighty consecutive brain-dead patients admitted from 1st October 1998 to 31st December 2000 out of which 112 gave at least one organ were analyzed. Among these 112 patients, 59 (39 males and 20 females) were pre-selected as potential heart donors. Only 44 hearts were harvested. Logistic regression analysis showed that harvesting of the heart was more probable if the donor were a male, had no left ventricle systolic wall motion abnormalities, had low doses of norepinephrine and low serum troponin Ic concentrations.

CONCLUSION

After an initial phase of selection, the final decision to harvest a heart is based on several criteria. These results should be an incentive to conceive a score that could allow a more formal decision process for heart harvesting.

Evaluation of donor cardiac function for heart transplantation: experience of a French academic hospital

OBJECTIVES

The diagnostic and therapeutic approaches for evaluation and management of cardiac function in brain-dead patients vary from country to country. The aim of the present study was to describe the results of the evaluation of brain-dead patients as potential cardiac donors in a French teaching hospital that manages the largest number of brain-dead patients in France.

METHODS

Demographic parameters, the causes of brain death, clinical evolution, hemodynamic parameters, doses of inotropic and/or vasopressive drugs, the results of echocardiographic examination, and several biochemical markers of myocardial cell injury were retrospectively collected.

RESULTS

Seventy-one consecutive brain-dead patients admitted to the intensive care unit of the Academic Hospital of Nancy from October 1st, 1998 to September 30, 1999 were analyzed. Twenty-nine patients were considered as potential heart donors: 22 males and 7 females aged 33 +/- 3 years (Mean + SEM). The cause of brain death was head trauma in 17 cases (59%), cerebrovascular disease in 10 cases (34%), and cerebral anoxia related to cardiac arrest in 2 cases (7%). Eighteen hearts (18/29 or 66%) were harvested and transplanted with a favorable outcome at one month in 17 cases. In 11 cases, the heart was not harvested, nine (9/29 or 31%) because of myocardial dysfunction upon subsequent echocardiographic examination and 2 because of the lack of matched recipients.

CONCLUSION

Comparison of these results with those of other groups suggests that hormonal substitution with insulin and triiodothyronine in the presence of myocardial dysfunction could be of potential interest to correct myocardial dysfunction and increase the number of donor hearts.

Lipopolysaccharide-induced increase of prostaglandin E(2) is mediated by inducible nitric oxide synthase activation of the constitutive cyclooxygenase and induction of membrane-associated prostaglandin E synthase

NO produced by the inducible NO synthase (NOS2) and prostanoids generated by the cyclooxygenase (COX) isoforms and terminal prostanoid synthases are major components of the host innate immune and inflammatory response. Evidence exists that pharmacological manipulation of one pathway could result in cross-modulation of the other, but the sense, amplitude, and relevance of these interactions are controversial, especially in vivo. Administration of 6 mg/kg LPS to rats i.p. resulted 6 h later in induction of NOS2 and the membrane-associated PGE synthase (mPGES) expression, and decreased constitutive COX (COX-1) expression. Low level inducible COX (COX-2) mRNA with absent COX-2 protein expression was observed. The NOS2 inhibitor aminoguanidine (50 and 100 mg/kg i.p.) dose dependently decreased both NO and prostanoid production. The LPS-induced increase in PGE(2) concentration was mediated by NOS2-derived NO-dependent activation of COX-1 pathway and by induction of mPGES. Despite absent COX-2 protein, SC-236, a putative COX-2-specific inhibitor, decreased mPGES RNA expression and PGE(2) concentration. Ketoprofen, a nonspecific COX inhibitor, and SC-236 had no effect on the NOS2 pathway. Our results suggest that in a model of systemic inflammation characterized by the absence of COX-2 protein expression, NOS2-derived NO activates COX-1 pathway, and inhibitors of COX isoforms have no effect on NOS2 or NOS3 (endothelial NOS) pathways. These results could explain, at least in part, the deleterious effects of NOS2 inhibitors in some experimental and clinical settings, and could imply that there is a major conceptual limitation to the use of NOS2 inhibitors during systemic inflammation.

Retinoic acid and lipopolysaccharide act synergistically to increase prostanoid concentrations in rats in vivo

Vitamin A and its active metabolite retinoic acid (RA) modulate host-pathogen interactions by interfering with the host immune and inflammatory response including prostaglandin (PG) biosynthesis. The effects of RA on phospholipase A(2) (PLA(2)) and cyclooxygenase (COX) isoforms in vitro are controversial, and few in vivo studies exist. We investigated the in vivo effects of RA on PG biosynthesis in the presence or absence of lipopolysaccharide (LPS) in rats. RA alone [10 mg/(kg. d) for 5 d] increased plasma and liver PG concentrations by increasing COX-1 protein expression (twofold that of control rats). RA acted synergistically with LPS to increase plasma (400-fold) and liver (15-fold) concentrations of prostaglandin E(2) (PGE(2)) and significantly, but to a lesser extent, other PG compared with RA rats, in the absence of major differences in PLA(2) expression or activity or COX-1 and COX-2 mRNA or protein expression. The RA + LPS-mediated increase in PGE(2) was significantly attenuated (97%) by aminoguanidine (AG), a relatively specific inhibitor of the inducible nitric oxide synthase (NOS2), consistent with the previously reported synergistic effect of RA and LPS on NOS2 expression and activity. In addition, RA and LPS induced the expression of the microsomal isoform of PGE synthase (mPGES). In conclusion, in vivo, RA and LPS increased PG and especially PGE(2) concentrations. The PGE(2) increase was associated with NOS2-mediated activation of COX and induction of mPGES. These results contribute to the characterization of the effects of vitamin A on the host inflammatory response.

Life-threatening pneumothorax of the ventilated lung during thoracoscopic pleurectomy

PURPOSE

To report the case of a patient who underwent right thoracoscopic pleurectomy with lung exclusion and developed contralateral (left) pneumothorax with resulting life-threatening alteration of the respiratory and cardiovascular functions.

CLINICAL FEATURES

A 28-yr-old male was admitted to the intensive care unit for a well tolerated, second episode of spontaneous right pneumothorax and scheduled for right thoracoscopic pleurectomy. Anesthesia was induced and maintained with sufentanil and propofol. A double lumen endotracheal tube (ETT) was inserted, its correct positioning checked clinically and by fiberoptic bronchoscopy and the patient was placed in the left decubitus position. Approximately one hour into the procedure, during the second period of right pulmonary exclusion, SpO2 values decreased within two minutes to 78%. End tidal capnography (EtCO2) values decreased to 6-8 mmHg within seconds and peak airway pressure increased to values between 50 and 60 cm H2O. Severe cyanosis, sinus bradycardia and arterial hypotension developed. The surgical procedure was stopped, propofol administration discontinued, bipulmonary ventilation reinstituted and the patient placed in the supine position which restored hemodynamic and respiratory function. Inspection and auscultation were consistent with tension left pneumothorax which was evacuated.

CONCLUSION

Pneumothorax of the ventilated lung during one lung ventilation for thoracoscopic procedures must be diagnosed quickly. Reinstitution of bipulmonary ventilation should probably be the first therapeutic attitude.

Retinoic acid attenuates inducible nitric oxide synthase (NOS2) activation in cultured rat cardiac myocytes and microvascular endothelial cells

S. Grosjean, Y. Devaux, C. Seguin, C. Meistelman, F. Zannad, P.-M. Mertes, R. A. Kelly and D. Ungureanu-Longrois. Retinoic Acid Attenuates Inducible Nitric Oxide Synthase (NOS2) Activation in Cultured Rat Cardiac Myocytes and Microvascular Endothelial Cells. Journal of Molecular and Cellular Cardiology (2001) 33, 933-945. The inducible NO synthase (NOS2) in cardiac tissue contributes to myocardial and coronary inflammation and dysfunction. Several natural (endogenous) hormones such as retinoic acid, the active metabolite of vitamin A, have the ability to attenuate NOS2 activation in inflammatory cells. The aim of this study was to investigate the effect of RA on NOS2 activation in cultured cardiac microvascular endothelial cells (CMEC) and adult rat ventricular myocytes (ARVM). CMEC were stimulated either with a combination of 10 microg/ml lipopolysaccharide (LPS) and 50 IU/ml interferon- gamma (IFN- gamma) or with a combination of 1 ng/ml interleukin-1 beta (IL-1 beta)+IFN- gamma whereas ARVM were stimulated with 1 ng/ml IL-1 beta and 50 IU/ml IFN- gamma in the absence or presence of all-trans retinoic acid (atRA). Activation of the NOS2 pathway was estimated by measurement of mRNA (Northern blot) and protein (Western blot) expression, enzyme activity by conversion of [(3)H]L -arginine to [(3)H]L -citrulline, and nitrite accumulation. NOS2 mRNA half-life was studied in CMEC and ARVM in the presence of actinomycin D. In CMEC and ARVM stimulated with a combination of LPS and/or cytokines, atRA (10(-6), 10(-5)M) significantly (P<0.05) attenuated NOS2 mRNA and protein expression, enzymatic activity and reduced supernatant nitrite concentration. Upon stimulation with LPS/IFN- gamma, atRA significantly decreased NOS2 mRNA half-life. This was not seen after stimulation with IL-1 beta/IFN- gamma. These results document for the first time an effect of RA on NOS2 activation in cardiac cells. They may contribute to the characterization of the immunomodulatory effects of retinoids in myocardial and coronary inflammatory disorders.

Retinoic acid and host-pathogen interactions: effects on inducible nitric oxide synthase in vivo

Vitamin A and its metabolite retinoic acid modulate the host response to pathogens through poorly characterized mechanisms. In vitro studies have suggested that retinoic acid decreases inducible NO synthase (NOS2, or iNOS) expression, a component of innate immunity, in several cell types stimulated with lipopolysaccharide (LPS) or cytokines. This study investigated the effect of retinoic acid on LPS-stimulated NOS2 expression in vivo. Wistar-Kyoto rats received all-trans retinoic acid (RA, 10 mg/kg) or vehicle intraperitoneally daily for 5 days followed by LPS (4 mg/kg) or saline intraperitoneally and were killed 6 h later. NOS2 activation was estimated by mRNA (RT-PCR) and protein (Western-blot) expression and plasma nitrate/nitrite accumulation. In sharp contrast to previous in vitro study reports, RA significantly enhanced NOS2 mRNA, protein expression, and plasma nitrate/nitrite concentration in LPS-injected rats but not in saline-injected rats. This was associated with increased expression of interleukin-2, interferon (IFN)-gamma and IFN regulatory factor-1 mRNAs in several organs and increased IFN-gamma plasma concentration. RA significantly increased mortality in LPS-injected rats. The NOS inhibitor aminoguanidine (50 mg/kg before LPS injection) significantly attenuated the RA-mediated increase in mortality. These results demonstrate for the first time that RA supplementation in vivo enhances activation of the LPS-triggered NOS2 pathway.

Effects of normothermic cardiopulmonary bypass on bispectral index

This study investigated the changes in the hypnotic component of anaesthesia, estimated by the bispectral index of the electroencephalogram, during normothermic cardiopulmonary bypass. Twenty-six patients (20 men, 6 women), aged 61 +/- 11 years (Mean +/- SD) scheduled for cardiac surgery were premedicated with hydroxyzine and meperidine. Anaesthesia was induced and maintained with a computer-controlled continuous infusion (not adjusted for haemodilution) of sufentanil (effect site concentration 0.4-0.6 ng mL-1) and a manually adjusted continuous infusion of propofol (4.4 +/- 1.8 mg kg-1 h-1). Cardiopulmonary bypass was normothermic with moderate haemodilution. Bispectral index was measured with a referential montage before, 30 s, 1, and 3 min after cardiopulmonary bypass onset, before and after aortic cross-clamping, 30 min after cardiopulmonary bypass onset, before and after aorta cross-clamp release and before and after weaning from cardiopulmonary bypass. Bispectral index values were 48 +/- 8 before cardiopulmonary bypass onset, 50 +/- 10 before, and 48 +/- 8 after end of cardiopulmonary bypass (P = NS). No patient had increases in bispectral index values during cardiopulmonary bypass consistent with awakening. We conclude that with the anaesthetic regimen presented in this study bispectral index values do not change during normothermic cardiopulmonary bypass.

Recombinant hirudin anticoagulation for aortic valve replacement in heparin-induced thrombocytopenia

PURPOSE

To report the case of a patient with HIT that received a prolonged infusion of r-hirudin (lepirudin; Refludan; Hoechst, France) before, during and after cardiopulmonary bypass (CPB) for aortic surgery. Although administration of r-hirudin for CPB anticoagulation has previously been reported, many questions persist concerning the best therapeutic regimen for CPB anticoagulation as well as the time of onset and the doses for postoperative anticoagulation.

CLINICAL FEATURES

A 65-yr-old man was admitted for surgery of aortic stenosis after an episode of acute pulmonary edema complicated by deep venous thrombosis in the context of documented HIT. The patient received r-hirudin for 13 dy before surgery at doses (0.4 mg x kg(-1) bolus followed by 0.15 mg x kg(-1) x hr(-1) continuous infusion) that maintained activated partial thromboplastin time (aPTT) ratios between 2 and 2.5. Anticoagulation for CPB was performed with r-hirudin given as 0.1 mg x kg(-1) i.v. bolus and 0.2 mg kg(-1) in the CPB priming volume. Anticoagulation during CPB was monitored with the whole blood activated coagulation time and ecarin clotting time (ECT) performed in the operating room with values corresponding to r-hirudin concentrations >5 microg x ml(-1) during CPB. Anticoagulation during CPB was uneventful. Two bleeding episodes, related to the r-hirudin regimen and necessitating allogeneic blood transfusion, occurred after surgery.

CONCLUSION

This case report confirms previous experience of the use of r-hirudin for anticoagulation during CPB and provides additional information in the context of prolonged r-hirudin infusion before and after CPB.

[Pharmacodynamics and safety of mivacurium in infants and children under halothane-nitrous oxide anesthesia]

OBJECTIVES

To determine pharmacodynamic effects and safety of mivacurium in paediatric patients.

STUDY DESIGN

Multicentric, prospective, open, non-randomized study.

PATIENTS

Forty-eight three-month-old to eight-year-old physical class ASA I or II children.

METHOD

Anaesthesia was induced and maintained with halothane and nitrous oxide. Tracheal intubation was performed without a neuromuscular blocking agent. Neuromuscular blockade was measured with a strain force transducer after train-of-four stimulation of the ulnar nerve at the wrist every ten seconds. A single bolus dose of mivacurium (0.2 mg.kg-1) was injected during 15 seconds in patients allocated into three groups. Group 1: three to 12-month-old infants (n = 15), group 2: one- to three-year-old children (n = 16) and group 3: three- to eight-year-old children (n = 17). Onset and recovery parameters were measured in each patient. Heart rate and noninvasive arterial blood pressure were recorded every minute for five minutes after mivacurium injection.

RESULTS

Following halothane administration for 29 and 32 min, and a FEThalothane = 1 vol%, mivacurium (0.2 mg.kg-1) determined a 100% neuromusmcular blockade in all patients. The onset time was 71 +/- 34 s (mean +/- SD) in all patients and did not differ between groups. Time to 25% and 95% recovery of the first twitch and recovery index for all the patients were 12 +/- 3 min, 19 +/- 5 min and 4 +/- 2 min respectively and did not differ between groups. No prolonged paralysis was observed. No significant changes of HR and BP occurred.

CONCLUSIONS

Following 0.2 mg.kg-1 of mivacurium in patients aged between three months to eight years, a complete blockade occurs with a rapid onset time and a short duration of action, without significant cardiovascular effect.

Monitoring orbicularis oculi predicts good intubating conditions after vecuronium in children

PURPOSE

The aim of the study was to compare visual estimation of onset of neuromuscular blockade at both the adductor pollicis (AP) and the orbicularis oculi (OO) in children and to determine if monitoring the OO could predict good intubating conditions during vecuronium-induced neuromuscular blockade.

METHODS

Thirty ASAI--II children (1.5-9 yr) were studied. Anaesthesia was induced with 6-8 mg.kg-1 thiopentone. The ulnar nerve at the wrist and the temporal branch of the facial nerve were stimulated every 10 sec using train-of-four (TOF) stimuli. Vecuronium, 0.15 mg.kg-1, was administered as a bolus. The responses at both the OO and the AP were evaluated visually. Patients were randomly divided into two groups. In the AP group (n = 15), the trachea was intubated when the AP was completely blocked. In the OO group (n = 15), intubation was performed when the OO was completely blocked. Intubating conditions were scored on a scale of 1 to 4.

RESULTS

All the patients had complete blockade at both the orbicularis oculi and the adductor pollicis. In the two group, time from injection of vecuronium to complete neuromuscular blockade was shorter at the orbicularis oculi than at the adductor pollicis, 1.5 +/- 0.5 min vs 2.3 +/- 0.7 min, respectively, (P < 0.05; mean +/- SD) in the AP group, 1.7 +/- 0.3 min vs 2.3 +/- 0.8 min, respectively in the OO group (P < 0.05). Intubating conditions were excellent in all patient except one, where it was rated as good. They did not differ between groups.

CONCLUSION

Following administration of 0.15 mg.kg-1 vecuronium in children, monitoring of the OO can detect good intubating conditions 0.7 min earlier than with monitoring of the AP.

ORG 9487 neuromuscular block at the adductor pollicis and the laryngeal adductor muscles in humans

BACKGROUND

ORG 9487 is a new steroidal nondepolarizing muscle relaxant with a rapid onset of action. This study was designed to determine the neuromuscular blocking profile of ORG 9487 at the adductor muscles of the larynx and the adductor pollicis.

METHODS

In 30 adults, anesthesia was induced with propofol (2-5 mg/kg) and fentanyl (2-3 microg/kg). After train-of-four stimulation, the block of the laryngeal adductor muscles was evaluated by measuring the pressure changes in the cuff of the tracheal tube placed between the vocal cords, and the force of the contraction of the adductor pollicis was measured with a force transducer. Patients were randomly allocated to receive ORG 9487 at intravenous bolus doses of 0.75, 1.5 or 2 mg/kg (n = 10 in each group).

RESULTS

Time to peak effect was significantly shorter at the vocal cords than at the adductor pollicis muscle (P < 0.001). Onset time at the vocal cords was 62 +/- 16 s, 62 +/- 13 s, and 52 +/- 14 s (mean +/- SD) after doses of 0.75, 1.5, and 2 mg/kg, respectively (not significant). Onset time at the adductor pollicis muscle was 126 +/- 33 s, 96 +/- 20 s, and 82 +/- 21 s after 0.75, 1.5, and 2 mg/kg doses, respectively (P < 0.001). Maximum block was significantly less intense at the vocal cords than at the adductor pollicis muscle (69 +/- 15% vs. 94 +/- 4% after 0.75 mg/kg; 86 +/- 7% vs. 97 +/- 4% after 1.5 mg/kg; and 91 +/- 5% vs. 99 +/- 1% after 2 mg/kg). After 1.5 mg/kg duration to 25%, recovery was 3.7 +/- 2.2 min versus 10.2 +/- 2.5 min at the vocal cords and the adductor pollicis muscle, respectively, and 75% recovery occurred at 9.7 +/- 3.7 min at the vocal cords and at 18.3 +/- 5.2 min at the adductor pollicis muscle.

CONCLUSIONS

ORG 9487 has a rapid onset of action at the laryngeal adductor and the adductor pollicis muscles. Onset and duration of action are faster at the vocal cords than at the adductor pollicis muscle. However, the maximum block obtained at the laryngeal muscles was less than at the adductor pollicis, regardless of the dose of ORG 9487.

Neuromuscular blockade: is it still useful in the ICU?

Neuromuscular relaxants may be administered to ICU patients for days or weeks. The most frequent indications are facilitation of mechanical ventilation and management of neurosurgical patients after severe head injury. Tachyphylaxis can be observed in ICU patients but the major problem remains the prolonged weakness which can occur after long-term administration of muscle relaxants. The mechanisms are still poorly understood and under investigation. Although neuromuscular monitoring provides guidelines for the administration of muscle relaxants in critically ill patients, it does not prevent the development of a myopathy.

Mivacurium neuromuscular block at the adductor muscles of the larynx and adductor pollicis in humans

BACKGROUND

Laryngeal muscles must be paralyzed for tracheal intubation. Time to peak effect (onset time) is shorter and intensity of blockade is less at laryngeal muscles compared with the adductor pollicis. The authors' aim in this study was to determine the neuromuscular effects of mivacurium at the laryngeal adductor muscles and the adductor pollicis.

METHODS

In 22 adults, anesthesia was induced and maintained with propofol and alfentanil. The force of contraction of the adductor pollicis was recorded, and the laryngeal response was evaluated by measuring the pressure change in the cuff of a tracheal tube positioned between the vocal cords after train-of-four stimulation. Mivacurium (0.07 mg.kg-1 or 0.14 mg.kg-1) was given intravenously (10s).

RESULTS

With 0.07 mg.kg-1 mivacurium, onset time was 151 +/- 40 s(mean +/- SD) at the larynx and 241 +/- 79 s at the adductor pollicis, respectively (P < 0.005). Maximum block was 78 +/- 18% and 95 +/- 8%, respectively (P < 0.002), and time to 90% recovery was 11.1 +/- 2.9 min and 23.3 +/- 7.6 min, respectively (P < 0.001). With 0.14 mg.kg-1 mivacurium, onset time also was more rapid at the vocal cords (137 +/- 20 s) than at the adductor pollicis (201 +/- 59 s, P < 0.01). Maximum block was 90 +/- 7% and 99 +/- 1% (P < 0.005), and time to 90% recovery was 16.4 +/- 4.9 min and 27.4 +/- 7.8 min, respectively (P < 0.01).

CONCLUSIONS

With mivacurium, onset and recovery are faster at the laryngeal muscles, but block is less intense than at the adductor pollicis. A dose greater than 0.14 mg.kg-1 mivacurium is necessary to ensure complete relaxation at the vocal cords.

[Effects of propofol on blood concentration of cyclosporine]

OBJECTIVE

This study was designed to assess whether propofol modifies the blood concentrations of cyclosporine and lipoproteins, which bind cyclosporine.

STUDY DESIGN

Prospective open study.

PATIENTS

Fifteen consecutive grafted patients, scheduled for surgery allowing them to resume their oral treatment postoperatively. Their immunosuppressive treatment, included cyclosporine (Cy A), at a steady-state dosage.

METHODS

Blood samples were drawn and residual Cy A blood concentrations were measured the days before and after anaesthesia and before and immediately after discontinuing the propofol infusion. Serum triglycerides, cholesterol, high-density lipoprotein (HDL) concentrations were measured before and immediately after discontinuing the propofol infusion.

RESULTS

The 15 patients were given propofol by infusion for 30-210 min (mean 85 +/- 59 min). They received a total dose of propofol of 696 +/- 497 mg, a total fentanyl dose of 175 +/- 82 micrograms, and a total midazolam dose of 2.8 +/- 0.8 mg. The residual cyclosporine blood concentrations were similar the day before (142 +/- 47 ng.mL-1) and following anaesthesia (128 +/- 46 ng.mL-1) (P = 0.08). Serum cholesterol concentrations were not significantly influenced by propofol infusion, but serum triglycerides levels increased (1.46 +/- 0.66 vs 1.97 +/- 0.81 g.L-1), and HDL and LDL levels decreased (0.54 +/- 0.20 vs 0.47 +/- 0.18 g.L-1; 1.44 +/- 0.42 vs 1.28 +/- 0.37 g.L-1).

CONCLUSION

Propofol by infusion does not modify the cyclosporine concentration. It is concluded that propofol may be a suitable agent for intravenous anaesthesia in cyclosporine treated patients, provided a close postoperative monitoring of cyclosporine blood concentrations is maintained.

Pharmacokinetics and pharmacodynamics of rocuronium at the vocal cords and the adductor pollicis in humans

The pharmacokinetic-pharmacodynamic relationship of rocuronium at the laryngeal adductor muscles and the adductor pollicis was determined in eight patients during general anesthesia. Rocuronium was administered as an infusion at a rate of 100 micrograms.kg-1.min-1 over 5 minutes. The half-life of transport between plasma and biophase (effect compartment) was significantly shorter at the adductor laryngeal muscles (2.7 +/- 0.6 minutes, mean +/- SD) than at the adductor pollicis (4.4 +/- 1.5 minutes, p = 0.003). The concentration in the effect compartment producing 50% of the maximum effect was significantly greater at the adductor laryngeal muscles (1424 +/- 148 micrograms.L-1) than at the adductor pollicis (823 +/- 157 micrograms.L-1, p = 0.0001). The shorter onset of neuromuscular blockade at the laryngeal muscles than at the adductor pollicis may be explained by a faster transfer rate at the laryngeal adductor muscles neuromuscular junction than at the adductor pollicis neuromuscular junction.