Comparison of acoustic and impedance methods with mask capnometry to assess respiration rate in obese patients recovering from general anaesthesia.

Respiratory depression, a potentially serious complication after general anaesthesia, can be detected promptly by close monitoring of both oxygen saturation and respiratory rate. Obese patients have morphological changes that may impair the reliability of monitoring devices. In this study, respiration rate was simultaneously recorded every second for up to 60 min using a computer in 30 adult obese patients (body mass index ≥ 35 kg.m(-2)), by three methods: acoustic; thoracic impedance; and capnometry via a facemask (Capnomask, reference method). Of the 99,771 data triplets collected, only 85,520 (86%) were included; 12,021 (84%) were not studied due to failure of capnometry and 2240 (16%) due to failure of the acoustic method. Compared with capnometry, bias was similar using both the acoustic method and impedance (-0.3 bpm vs. -0.6 bpm, respectively, p = 0.09), but limits of agreement were narrower for the acoustic method (±3.5 bpm vs. ±5.3 bpm, respectively, p = 0.0008). The proportion of respiration rate values obtained with the acoustic method and impedance that differed by at least 10% or 20% for more than 15 s were 11% vs. 23% and 2% vs. 6%, respectively (p = 0.0009 for both comparisons). The acoustic sensor was well tolerated, while the facemask was pulled off on several occasions by four (13%) agitated patients. In obese patients requiring close monitoring of respiration rate, the acoustic method may be more precise than thoracic impedance and better tolerated than capnometry with a facemask.

[Vasoreactivity changes during extracorporeal circulation: effects of halogenated agents]. / Modifications de la vasoréactivité en CEC : influence des halogénés.

During cardiopulmonary bypass (CPB), endothelium is exposed to multiple disturbances leading to significant vasomotor tone and vascular systemic resistances (VSR) level modifications. Properties of endothelial function on vascular tone were summarized herein. According bibliographic findings, physiological and clinical impacts of respectively halogenated agents and CPB concerning vasomotor tone were reported. Main effects of halogenated agents administered through oxygenator during CPB were also identified. Usually when administered above one MAC, halogenated agents decreased VSR during hypothermic bypass. Once those mechanisms summarized, increase of halogenated agent's effects on VSR during normothermic CPB was postulated. Assuming that decrease of VSR could be deleterious favoring severe vasoplegia event, clinical experience of administration of isoflurane during CPB among more 4000 patients was retrospectively reported. Incidence of severe vasoplegia was established to 9.5 % in the studied population and this result was similar as others. More over predicting factors of severe vasoplegia were the same as previously reported : severity of preoperative clinical status according Euroscore, hemodynamical instability before induction of anesthesia, surgical procedure complexity and CPB duration. Absence of deleterious effects in SVR decrease when administering isoflurane during normothermic CPB was assumed but prospective comparative studies comparing effects of halogenated agents and other anesthetic agents are needed in order to confirm these findings.

[Survey on the training and organisation of cardiopulmonary bypass for cardiac surgery in France]. / Enquête française sur la prise en charge de la circulation extracorporelle et la formation des perfusionnistes en 2008.

INTRODUCTION: Cardiopulmonary bypass (CPB) is a medical act that can be performed by nurses as long as they are constantly supervised by a physician. No initial formalized training course is required. The personal responsibilities of nurses and physicians about CPB have not been defined. OBJECTIVES: The purpose of this study was: to list perfusionists; to evaluate the training of perfusionists; to determine which physicians are considered as in charge during actions performed by paramedics, as well as their qualification; to point out the changes since 1997. TYPE OF STUDY: Professional practice assessment. METHODS: A questionnaire was sent to all perfusionists in activity in France. RESULTS: There were 71% of replies. We found an aging of perfusionists (median 49 years vs. 40 years in 1997), a fall in the proportion of trained physicians (13% of perfusionists had a training course in adequacy with professional guidelines, 25% of perfusionists said they worked with a physician who could intervene at all time, and 61% declared only one physician was in charge). There is no CPB referent in 26% of perfusion units. CONCLUSION: An urgent need appears to define the respective responsibilities of medical and paramedical perfusion staff, especially as this technique spreads out of the conventional cardiac surgery operating theatres.

[Analysis of incidents, monitoring and safety devices of cardiopulmonary bypass for cardiac surgery for the year 2005 in France]. / Analyse des accidents, des moyens de monitorage et de sécurité de la circulation extracorporelle pour chirurgie cardiaque en France en 2005.

INTRODUCTION: Several surveys demonstrated that cardiopulmonary bypass (CPB) is associated with incidents that negatively affect the outcome of cardiac surgery. OBJECTIVES: In 2004, the French "Haute Autorité de santé" (an independent public scientific authority) and the French "College of Perfusion" issued recommendations concerning safety and monitoring devices for CPB. The aims of the present study were to: 1) investigate the difference between the recommendations and the clinical practice of CPB shortly after publication of the recommendations; 1) investigate the type and rate of perfusion incidents and their outcome. STUDY DESIGN: Retrospective survey. METHODS: A 62 items questionnaire was sent to all 66 centres performing cardiac surgery in France. RESULTS: Fifty-seven centres totalling 34,496 CPB procedures (response rate 86%) returned the questionnaire. There was a wide difference between the recommendations and the reported use of safety and monitoring devices. An incident was reported for every 198 CPB procedures with death occurring 1:4,864 and permanent sequelae 1:11,349 procedures respectively (permanent injury or death 1:3,220 procedures). The most frequent perfusion incidents were adverse effects to protamine (1:1,702), dissection at the arterial canulation site (1:1,792) and coagulation of the circuit (1: 4,864). CONCLUSION: This survey demonstrates that an important effort must be made in order to fill the gap between the recommendations and clinical use of monitoring and safety devices. The analysis of CPB-related incidents suggests that, with the exception of protamine adverse effects, the majority of deaths and severe permanent injuries could probably be avoided by improved use of the monitoring and safety devices.

[Lepirudin during cardiopulmonary bypass in a patient with heparin-induced thrombocytopenia]. / Circulation extracorporelle sous lépirudine (Refludan) dans un contexte de thrombopénie induite par l'héparine.

Lepirudin is an alternative anticoagulant therapy in heparin-induced thrombocytopenia (HIT) during cardiopulmonary bypass (CPB). We report a case of a female patient with HIT referred for aortocoronary bypass graft despite persistence of antibodies to platelet factor 4-heparin complexes. Anticoagulation management is described. Whole blood hirudin concentration attempted during CPB was above 4 microg ml(-1). To obtain this concentration, lepirudin administration was managed as follows: 0.1 mg kg(-1) h(-1) lepirudin during preoperative course, 0.2 mg kg(-1) bolus just before CPB and 0.2 mg kg(-1) in the priming solution, complementary boluses of 5 and 10 mg during procedure (according to whole blood ecarin clotting time). Aprotinin was administered simultaneously according to Royston protocol. Anticoagulation was monitored with whole blood ecarin time performed in the operation room (patient's whole blood was diluted one half and one third with normal whole blood; in vitro calibration curve was constructed using normal whole blood spiked with lepirudin). CPB duration was 73 min. When measured, whole blood hirudin concentration was 3.8-5.8 microg ml(-1). Total lepirudin administration was 44 mg. No haemorrhagic or thrombotic events were observed during surgical procedure and postoperative course. Despite lepirudin administration is not yet clearly precise for CPB procedure, its use seems adapted and safe in subjects without renal insufficiency but requiring precise coordination for anaesthesiological, surgical and biological teams.

[French national survey of the use of monitoring devices during cardiopulmonary bypass in 2001]. / Enquête française sur les dispositifs de surveillance de la CEC en 2001.

OBJECTIVES: To study the different monitoring devices used during cardiopulmonary bypass (CPB) and to determine the factors, which may influence the choice of these equipments. STUDY DESIGN: Survey. METHODS: A postal questionnaire was send to the 66 French cardiac surgery centres. Results have been analysed about the economic status (public health service or private institution) and the business of the centre (less than 500, between 500 to 800 and more than 800 cardiopulmonary bypass/year). RESULTS: The rate of answer reached 73%. In 40% of centres, the cardiovascular perfusionist was not alone during the procedure. The percentage of centres using a checklist was 80%, a neurologic monitoring 42%, anaesthesia depth monitoring 40%, venous reservoir level detector 52%, arterial line bubble detector 38%, cardioplegia circuit bubble detector 6%, transoesophageal echocardiography 48%, pipe's temperature monitoring 90%; oxymetry 44%, capnography 25%, SvO2 98%, blood gas analysis outside the OR 46% and computer records 35%. No difference was observed between public and private institution for these latter devices. However, a significant difference was noticed among the low, intermediate and highly busy centres for the use of checklist, the EEG monitoring, the pipe and water circuit temperature monitoring, capnography and location of the biologic analysers. CONCLUSION: Equipments were not similar among the different French cardiac surgery centres. Furthermore, the French practice seems different from American, UK and Australian's one. These results highlight the need of establishing French guidelines, which are absent.

[Rupture of ascending aortic aneurysm revealing Takayasu's arteritis]. / Rupture d'un anévrisme de l'aorte ascendante révélant une artérite de Takayasu.

Takayasu's disease is rare in Western countries. It is most often revealed by stenosing lesions, aneurysmal attacks being less frequent, generally multifocal, and associated with stenoses. An isolated aneurysmal attack of the ascending aorta is exceptional. It is a deleterious factor in the disease process, and one of the causes of death in this disease. We report a case of isolated aneurysm of the ascending aorta extending to the aortic arch, undergoing emergency surgery at the rupture phase, revealing Takayasu's arteritis. Classically, isolated, asymptomatic, small aneurysms without lesions of other branches are slow to evolve with prolonged corticosteroid therapy. Our observation was contrary to these data, with rapid growth in a major inflammatory context, and rupture. It would seem important to rapidly diagnose and treat Takayasu's disease aneurysms of the ascending aorta, given their progressive potential. In a young female the signs of parietal thickening of the aneurysm must provoke diagnosis and treatment rapidly.

Use of cisatracurium during fast-track cardiac surgery.

We prospectively studied spontaneous recovery from cisatracurium-induced neuromuscular block in 18 patients scheduled for cardiac surgery, and its suitability for fast-track cardiac surgery. Neuromuscular block was induced by an i.v. bolus (range 0.15-0.3 mg kg(-1)) and maintained by a continuous infusion (range 1.1-3.2 microg kg(-1) min(-1)) of cisatracurium until sternal closure. In the intensive care unit (ICU), spontaneous recovery was evaluated by the train-of-four (TOF) ratio measured at the adductor pollicis muscle. The ICU medical staff were unaware of the TOF ratios until sedation was stopped. At that time, if the TOF ratio was less than 0.9, sedation was recommenced. On arrival in ICU, all patients had residual paralysis. The mean time to reaching a TOF ratio of at least 0.9 was 102 min (range 74-144 min) after discontinuation of the cisatracurium infusion. Fifteen patients (83%) were successfully extubated during the first 8 h after stopping the cisatracurium infusion. Only one patient showed residual paralysis when sedation was discontinued. These results support the use of cisatracurium as a suitable neuromuscular blocking agent for fast-track cardiac surgery.

Incidence of anaerobes in ventilator-associated pneumonia with use of a protected specimen brush.

The role of anaerobic bacteria in ventilator-associated pneumonia (VAP) has been little investigated. In this study we analyzed the incidence of anaerobes in patients with a first episode of bacteriologically documented VAP (> 10(3)CFU/ml), using protected specimen brushes (PSB). We particularly took care to preserve anaerobic conditions during transport and the microbiological procedure. Two groups were considered: group A with anaerobic bacteria recovered from PSB, with or without anaerobes, and group B with aerobic bacteria only. One hundred and thirty patients were included, 30 (23%) in group A, and 100 (77%) in group B. The main anaerobic strains isolated were Prevotella melaninogenica (36%), Fusobacterium nucleatum (17%), and Veillonella parvula (12%). Univariate analysis demonstrated that patients in group A were younger than those in group B (p < 0.05) and their simplified acute physiologic score was higher (p < 0.02). The percentage of patients receiving antibiotics before PSB did not differ significantly between group A (57%) and group B (35%). VAP with anaerobes occurred more often in patients orotracheally intubated than nasotracheally intubated (p < 0.02). Episodes of VAP involving anaerobic bacteria occurred more often in the first five days (early VAP) than after the fifth day (late VAP) (p < 0.05). The 3-mo mortality rate was similar in the two groups, but death occurred earlier in group B (p < 0.01). Multivariate analysis demonstrated that presence of altered level of consciousness (p = 0.0002), higher simplified acute physiologic score (p = 0.003), and admission to the medical ICU (p = 0.02) were the factors independently predisposing to the development of VAP with anaerobes.