Irreversible electron attachment – a key to DNA damage by solvated electrons in aqueous solution

In an aqueous solution trinucleotides labeled with bromonucleobases are damaged by ionizing radiation induced electrons while native trimers are insensitive to electrons under the same conditions.

Murine solid tumours as a novel model to study bacterial biofilm formation in vivo

Bacteria of many species are able to invade and colonize solid tumours in mice. We have focused on Salmonella enterica serovar Typhimurium. Detailed analysis revealed that such tumour-invading Salmonella form biofilms, thus providing a versatile in vivo test system for studying bacterial phenotypes and host-pathogen interactions. It appears that biofilm formation by S. typhimurium is induced as a defence against the immune system of the host, and in particular against neutrophils. Further, we extended our work to the clinically more relevant biofilm infection by Pseudomonas aeruginosa. The induction of P. aeruginosa biofilms in neoplastic tissue appears to be elicited as a reaction against the immune system. Reconstitution experiments reveal that T cells are responsible for biofilm induction. Isogenic mutants that are no longer able to form biofilms can be used for comparison studies to determine antimicrobial resistance, especially therapeutic efficacy against P. aeruginosa located in biofilms.

Cutaneous human papillomavirus E7 type-specific effects on differentiation and proliferation of organotypic skin cultures

Background: A role for cutaneous human β-papillomavirus (HPV) types as co-factors in the development of non-melanoma skin cancer has been postulated. Here we have investigated the effects of E7 expression on keratinocyte differentiation, proliferation and cell-cycle proteins in organotypic skin cultures.

Methods: Recombinant retroviruses containing the E7 genes from cutaneous HPV types 1, 4, 5, 8, 20, 38 and RTRX7 were produced that include types associated with benign and malignant lesions. Adult human primary keratinocytes were transduced with these recombinant retroviruses and differentiated into skin-equivalents using de-epidermalised human dermis.

Results: Expression patterns of the basal keratinocyte marker cytokeratin 14 (CK14) were not altered by any of the viral E7 types analysed. However, expression of the early and late differentiation markers CK10 and involucrin were markedly altered in HPV 1, 4 and 38 cultures. The highest proliferation rates in basal cell layers, as judged by BrdU and Ki67 staining, were observed in HPV 1, 4 and 38 cultures. Interestingly, co-expression of cyclin E and p16^INK4a within the same cell of the suprabasal cell layers was observed only in cultures generated using E7 of HPV 5 or HPV 8.

Conclusion: HPV types associated with either benign or malignant lesions perturb keratinocyte proliferation and differentiation in different ways. Moreover, expression of E7 from HPV 5 or HPV 8 seem able to overcome p16^INK4a induced cell cycle arrest in a subset of keratinocytes.

A patient with a "good nose"

We report on a 33-year-old man who underwent an odyssey of doctors for investigation of dysphagia. Eventually, a nasopharyngeal mass was found by several otorhinolaryngologists who repeatedly recommended biopsy or excision, because a polyp or fibroma was assumed on nasal endoscopy and MR imaging. However, we finally diagnosed the nasopharyngeal mass to be an ectopic pituitary gland after thorough clinical (cleft lip and palate) and radiological re-examination. Literally, the patient had a "good nose", since he refused manipulations on the nasopharyngeal tumour and assumably prevented inadvertent hypopituitarism. We conclude that biopsy or excision of nasopharyngeal masses should always be considered carefully, especially in patients with facial anomalies.

Roflumilast, a once-daily oral phosphodiesterase 4 inhibitor, lacks relevant pharmacokinetic interactions with inhaled salbutamol when co-administered in healthy subjects

OBJECTIVE

Roflumilast is an oral, once-daily phosphodiesterase 4 inhibitor under investigation for the treatment of chronic obstructive pulmonary disease and asthma. In clinical practice, the drug is likely to be co-administered with inhaled bronchodilating beta2-adrenoceptor agonists. Therefore, this study investigated the pharmacokinetic characteristics of roflumilast and its pharmacodynamically active metabolite roflumilast N-oxide when co-administered with orally inhaled salbutamol in healthy subjects.

METHODS

In this open, randomized clinical study, 12 healthy male subjects received repeated doses of oral roflumilast 500 microg once daily, orally inhaled salbutamol 200 microg 3 times daily, and a combination of both drugs over 7 days according to a 3-period, changeover design with 14 days washout between treatments.

RESULTS

Co-administration of roflumilast and salbutamol did not markedly change roflumilast or roflumilast N-oxide disposition. Point estimates (90% confidence intervals) of area under the curve from 0-24 h (AUC 0-24) and maximum plasma concentration in steady state (Cmax,ss) for roflumilast with salbutamol versus roflumilast alone were 1.05 (0.94, 1.17) and 0.97 (0.84, 1.10); the respective point estimates (90% confidence intervals) for AUC 0-24 and Cmax,ss of roflumilast N-oxide were 0.98 (0.91, 1.06) and 0.98 (0.92, 1.03). Roflumilast co-administration did not alter the pharmacokinetics of steady state salbutamol. The respective point estimates (90% confidence intervals) for AUC 0-6 and Cmax,ss of salbutamol with roflumilast versus salbutamol alone were 1.10 (0.99, 1.21), 1.08 (0.91, 1.28). The combination of both drugs was well tolerated.

CONCLUSION

There were no relevant pharmacokinetic interactions between roflumilast and salbutamol at therapeutically effective doses.

Postoperativ aufgetretene reversible posteriore Enzephalopathie bei einem Patientin mit Morbus Crohn

Posterior encephalopathy (PE) is a rare condition with different origins and unknown pathogenesis. We report on a case of a 16-year-old boy with Crohn's disease who developed PE after peridural anesthesia with ropivacain. A possible connection between PE, ropivacain and Crohn's disease is discussed on the basis of the current literature.

Positive end-expiratory pressure improves arterial oxygenation during prolonged pneumoperitoneum

BACKGROUND

Laparoscopic surgery usually requires the use of a pneumoperitoneum by insufflating gas in the peritoneal space. The gas most commonly used for insufflation is carbon dioxide. Increased intra-abdominal pressure causes cephalad displacement of the diaphragm resulting in compressed lung areas, which leads to formation of atelectasis, especially during mechanical ventilation. The aim of this prospective study was to investigate the effect of prolonged intraperitoneal gas insufflation on arterial oxygenation and hemodynamics during mechanical ventilation with and without positive end-expiratory pressure (PEEP).

METHODS

Twenty patients undergoing totally endoscopic robot-assisted radical prostatectomy were randomly allocated to one of two groups. In the PEEP group (n = 10) a constant PEEP of 5 cmH(2)O was used, whereas in the ZPEEP group (n = 10) no PEEP was used.

RESULTS

Application of PEEP (5 cmH(2)O) resulted in significantly higher P(a)O(2) levels after 3 h (182 +/- 49 vs. 224 +/- 35 mmHg) and 4 h (179 +/- 48 vs. 229 +/- 29 mmHg) of pneumoperitoneum; after desufflation, P(a)O(2) values decreased significantly below preinsufflation values. While there were no significant differences in heart rate, central venous pressure (CVP) and mean arterial blood pressure (MAP) during pneumoperitoneum between both groups, baseline values in CVP and MAP differed significantly between both groups with higher levels in the ZPEEP group.

CONCLUSION

The application of a constant positive airway pressure of 5 cmH(2)O preserves arterial oxygenation during prolonged pneumoperitoneum.

Peri-operative complications during percutaneous tracheostomy in obese patients

The safety of percutaneous tracheostomy in 73 obese patients (body mass index > or = 27.5 kg.m(-2)) in a cohort of 474 adults was studied. Four percutaneous techniques were employed (percutaneous dilational tracheostomy, n = 48; Ciaglia Blue Rhino, n = 157; guide wire dilating forceps, n = 62, translaryngeal tracheostomy, n = 207). The overall complication rate was 43.8% (n = 32) in the obese group compared to 18.2% (n = 73) in the control group (p < 0.001). Seven (9.6%) obese patients suffered life-threatening complications compared to three non-obese patients (0.7%, p < 0.001). Obese patients had a 2.7-fold increased risk for peri-operative complications, and a 4.9-fold increased risk for serious complications. The data suggest that percutaneous tracheostomy in obese patients is associated with a considerably increased risk for peri-operative complications, especially for serious adverse events.

PercuTwist-Dilatationstracheotomie

BACKGROUND

Percutaneous dilational tracheostomy (PDT) is considered to be an accepted method in intensive care patients. In 2002 Frova and Quintel described a method of dilation that employed controlled rotation of the PercuTwist dilational device. The goal of the present study was to evaluate the new technique employed by an experienced team.

PATIENTS AND METHODS

Prospective, observational clinical study in 54 intensive care patients who required PDT. All tracheostomies were accompanied by bronchoscopic control. Vital parameters and perioperative complications were registered.

RESULTS

In all 54 consecutive PercuTwist tracheostomies no severe complications were noted. Accidental tracheal ring fracture was noted in 7 patients while bleeding that needed surgical care occurred in 1 patient.

CONCLUSION

The PercuTwist tracheostomy is a safe procedure for intensive care patients. More prospective studies that would compare the PercuTwist tracheostomy with the other PDT methods are necessary.

Routine microbiological screening in septic patients in a cardiac surgical intensive care unit

INTRODUCTION

Patients in a surgical intensive care unit (ICU) have a high incidence of nosocomial infections which often lead to septic shock and death. Since specific antibiotic treatment is often difficult, it is recommended that routine nose/throat swabs be obtained in order to have a better idea of the causative agent when a systemic inflammatory response occurs in a given patient.

MATERIALS AND METHODS

In 1435 patients in a cardiac surgical ICU, routine nose/throat swabs were taken thrice a week and tested for microorganisms and systemic inflammation. Blood cultures were also obtained. Antibiotic treatment was given to cover the microbes from the nose/throat swabs. Alternatively, an empirical antibiotic therapy was given to patients whose swabs had tested negative.

RESULTS

Of the 86 patients with systemic inflammation, 29 had blood cultures positive for microbes. Of these, 18 received a specific antibiotic therapy based on their positive nose/throat cultures prior to the return of the blood cultures from the laboratory. However, only 11 patients tested positive for the same microbes on routine swabs and blood cultures. While positive routine swabs are quite specific to sepsis when there is a systemic inflammatory response, routine swabs are not a suitable screening tool due to their low sensitivity.

CONCLUSION

Routine nose/throat swabs led to earlier specific antibiotic treatment in only 22 % of patients with clinical signs of systemic inflammation. In 36 % of cases, the organisms detected in the routine swabs and blood cultures were not identical. Hence, we believe that routine swabs are of limited value in instituting earlier, specific antibiotic therapy in septic patients.

Prolonged intraperitoneal versus extraperitoneal insufflation of carbon dioxide in patients undergoing totally endoscopic robot-assisted radical prostatectomy

BACKGROUND

Extraperitoneal laparoscopic prostatectomy is an alternative to the intraperitoneal method. However, the effects of extraperitoneal carbon dioxide (CO2) insufflation on hemodynamics and respiratory data have not been adequately studied. This study compared the effects of prolonged intra- and extraperitoneal CO2 insufflation on hemodynamics and gas exchange.

METHODS

For this study, 20 patients were assigned to receive totally endoscopic robot-assisted radical prostatectomy (TERP) via the intra- or extraperitoneal approach. Hemodynamic parameters and respiratory data were obtained during 8 h of insufflation and analyzed for statistical differences.

RESULTS

With both insufflation methods, arterial CO2 pressure increased rapidly, reaching higher levels with extraperitoneal insufflation. Therefore, patients managed with extraperitoneal insufflation required a significantly higher minute ventilation. Heart rate and central venous pressure increased in both groups, whereas mean arterial blood pressure and pH decreased.

CONCLUSIONS

Prolonged intra- and extraperitoneal CO2 insufflation for TERP resulted in significant, but mostly clinically unimportant, hemodynamic alterations. Carbon dioxide absorption was more pronounced with extraperitoneal insufflation.

[Transthoracic defibrillation. Physiologic and pathophysiologic principles and their role in the outcome of resuscitation]

As one major link in the chain of survival, early transthoracic (external) cardiac defibrillation is aimed at the termination of ventricular flutter and ventricular fibrillation. Most important to the success of defibrillation is the passage of a defined amount of current through a critical mass of heart muscle. Different transthoracic resistances reduce the effective density of the current within the heart. As for other therapeutic intervention procedures, recommendations for the optimal strength of current to be applied to the fibrillating heart need to be evaluated and defined for therapeutical defibrillation too. Unnecessarily high current density causes damage to the heart and should be prevented. By using biphasic waveforms in contrast to monophasic impulses, the amount of current can be reduced but the same or even higher efficacy is attained. Therefore possible myocardial damage might be clearly reduced. Even with individually altered thoracic impedance effective conversion of cardiac rhythm can be achieved by device-controlled compensation and biphasic waveforms. According to their different mechanisms or origin (electrically induced or spontaneously caused by organic heart disease) the probability of successful conversion of the cardiac rhythm by one single electrical impulse varies. The optimum point in time for defibrillation during resuscitation needs to be redefined. In order to improve comparability, further studies should use standardized definitions for successful defibrillation relating to the resulting cardiac rhythm.

Echocardiographic findings in minimally invasive coronary artery bypass grafting: The role of intrathoracic CO2 - insufflation and single lung ventilation

BACKGROUND

Current options for surgical treatment of coronary single vessel disease range from beating heart procedure without cardiopulmonary bypass via a mini thoracotomy (MIDCAB) to totally endoscopic robot-assisted techniques (TECAB) with cardiopulmonary bypass. Both procedures are associated with considerable stress even before revascularization such as single lung ventilation, temporary coronary occlusion, Luxatio cordis, intrathoracic CO2 insufflation and extended bypass and operating time. The aim of the this study was to document the extent of intraoperative segmental wall motion abnormalities (SWMA) by echocardiography, and to identify variables affecting SWMA.

MATERIALS AND METHODS

Forty patients with coronary single vessel disease were included in the study. 16 patients were operated with the MIDCAB technique, and 24 patients underwent TECAB. In both groups of patients sequential transesophageal echocardiograms (2D-loops) were recorded and analyzed. Hemodynamic and electrocardiographic data as well as oxygenation parameters were acquired during echo exams. In both groups of patients mild, but significant perioperative SWMA were identified, which increased in the course of the operation. These SWMA were more pronounced in the TECAB as compared to the MIDCAB group. Independent of operating time these changes disappeared completely until the ends of surgery. Significant hemodynamic or elektrocardiographic modifications were not observed.

CONCLUSION

The application of minimally invasive techniques for the surgical treatment of coronary single vessel disease is associated with significant perioperative SWMA. The more pronounced SWMA in the TECAB group may be a consequence of intrathoracic CO2-insufflation. Both techniques can be applied without significant myocardial ischemia, provided that appropriate intraoperative monitoring is performed, and intrathoracic CO2 pressure in TECAB patients is limited.

Transesophageal echocardiography or fluoroscopy during port-access surgery?

INTRODUCTION

In Port-Access cardio-surgical procedures, both intraoperative transesophageal echocardiography (TEE) and fluoroscopy can be used for placement of the catheters and cannulae needed for cardiopulmonary bypass. Our study sought to clarify whether it is possible to rely exclusively on TEE for catheter placement without increasing the risk for the patient.

MATERIALS AND METHODS

Forty patients underwent cardiac surgery with the Port-Access system. Fluoroscopy as well as TEE were used for placement of the transjugular and transfemoral catheters required for cardiopulmonary bypass. The time required for fluoroscopy was recorded, as were any complications during cannulation and cardiopulmonary bypass.

RESULTS

The average fluoroscopy time was 10.7 +/- 12.1 min. Fluoroscopy time required for placement of the coronary sinus and pulmonary vent catheters could be reduced to zero early in the course of the study. Once we had gained enough experience with TEE, fluoroscopy for placement of the transfemoral catheters was also no longer necessary. During cannulation, 3 patients suffered complications requiring immediate surgical intervention. These complications were all diagnosed by TEE.

CONCLUSION

Our data suggest that positioning of the coronary sinus and the pulmonary vent catheters is safe and practicable with TEE alone. Nonetheless, if TEE imaging is poor or fails, fluoroscopy has still a place in Port-Access surgery and should always be available intraoperatively.

Totally endoscopic coronary artery bypass grafting on cardiopulmonary bypass with robotically enhanced telemanipulation: report of forty-five cases

BACKGROUND

Robotically enhanced telemanipulation is a new powerful tool for minimally invasive procedures that allows totally endoscopic cardiac surgery. Between June 1999 and February 2001, 45 robotically enhanced totally endoscopic coronary artery bypass grafting procedures on the arrested heart were performed at our institution with the use of the da Vinci telemanipulation system (Intuitive Surgical, Inc, Mountain View, Calif).

METHODS

In 37 patients a single-vessel totally endoscopic coronary bypass operation was performed. Eight patients had different types of multivessel revascularization with both internal thoracic arteries. The initial conversion rate was 22% and dropped to 5% in the last 20 patients. Two patients required reexploration via median sternotomy. The first 22 patients had excellent graft patency on discharge. The procedural time for single-vessel totally endoscopic bypass was 4.2 +/- 0.4 hours, bypass time was 136 +/- 11 minutes, and aortic crossclamp time amounted to 61 +/- 5 minutes.

CONCLUSION

The present data show the feasibility of closed chest single- and double-vessel revascularization, with good clinical results. However, procedural time is prolonged and the complex endoscopic and endoaortic occlusion techniques, as well as the extensive anesthesiologic monitoring, are demanding. The need for conversion to an open procedure diminished after a relatively short learning curve. All postulated benefits of totally endoscopic surgery other than excellent cosmesis must be evaluated in larger cohorts.

[The TRALI syndrome--a life-threatening transfusion reaction]

Transfusion related acute lung injury (TRALI) is a serious complication of blood transfusion, characterized by non-cardiogenic lung oedema. We describe a case of TRALI due to granulocyte-specific antibodies. The 58-year-old patient received 2 units of fresh frozen plasma following colon surgery and within 30 min the patient developed an acute respiratory distress syndrome. Granulocyte-specific antibodies were found in one of the transfused plasma of a female blood donor who most likely became immunized against granulocyte alloantigens during her three pregnancies.

Totally endoscopic Nissen fundoplication with a robotic system in a child

The Da Vinci robot device represents the latest advance in laparoendoscopic surgery. We report the case of an endoscopic Nissen fundoplication performed with the aid of a telemanipulation robot system in a 10-year-old girl. To our knowledge, this is the first such case to be reported. In addition to standard monitoring, we used invasive blood pressure monitoring during the 282-min period of general anesthesia. Arterial blood gas samples were analyzed at short intervals. During surgery, which included a 172-min period of intraperitoneal insufflation of carbon dioxide (CO2), no significant changes were observed in PH, arterial oxygen pressure (PaO2), arterial carbon dioxide pressure (PaCO2), heart rate, or mean arterial pressure. Body temperature was maintained with an external warming blanket. Total intravenous anesthesia with continously administered propofol, remifentanil, and mivacurium for continous muscle relaxation allowed extubation immediately after skin closure. The girl was discharged from hospital on postoperative day 6. Robot-assisted techniques have the potential to significantly improve the performance of laparoendoscopic surgery. However, despite our encouraging first results, the potential risks of robot-assisted surgery have not yet been definitively established. Therefore, patients submitted to this type of procedure require intensive and even invasive monitoring.

Surgeon's occupational exposure to nitrous oxide and sevoflurane during pediatric surgery

Health hazards from occupational exposure to trace concentrations of anaesthetic gases cannot be definitively excluded. The aim of the study was to determine the surgeon's occupational exposure to nitrous oxide and sevoflurane during pediatric surgical procedures. Twenty young children (age < 10 years) and five teenagers (age > 10 years) underwent elective abdominal surgery under general inhalational anesthesia. The operating room was equipped with modern air conditioning and waste anesthetic gas scavenger. Levels of both nitrous oxide and sevoflurane were determined in the breathing zone of the surgeon and the anesthesiologist during the operative procedures by means of a direct-reading photoacoustic infrared spectrometer. Both the surgeon and the anesthesiologist were exposed to low concentrations of the inhalational agents used. Exposure to sevoflurane and nitrous oxide was clearly higher during surgery in young children than during operative procedures in teenagers. Nonetheless, the concentrations of these agents were well below the threshold limits of 25 ppm for nitrous oxide and 2 ppm for sevoflurane recommended by the National Institute of Occupational Safety and Health. General anesthesia results in operating room air pollution with inhalational anesthetics. Under modern air conditioning, personnel's occupational exposure is low, and inhalational anesthesia is safe from the standpoint of modern workplace laws and health care regulations. Nonetheless, all efforts must be taken to maintain occupational exposure at this low level.

Incidence of gastrointestinal complications in cardiopulmonary bypass patients

Gastrointestinal complications after cardiac surgery are associated with a high mortality rate. Because of the absence of early specific clinical signs, diagnosis is often delayed. The present study seeks to determine predictive risk factors for subsequent gastrointestinal complications after cardiosurgical procedures. Within a 1-year period, a total of 1116 patients who had undergone open heart surgery with cardiopulmonary bypass were prospectively studied for gastrointestinal complications. To determine predictive factors, all case histories of the patients were analyzed. Of the 1116 patients, 23 (2.1%) had gastrointestinal complications during the postoperative period, 10 of whom had to undergo subsequent abdominal surgery. Of these 23 patients, 20 died. Early gastrointestinal complications, which occurred mostly on postoperative days 6 or 7, consisted of bowel ischemia or hepatic failure. Late complications were gastrointestinal bleeding, pseudomembranous colitis, cholecystitis, and septic rupture of a spleen. The relative risk for abdominal complications after cardiopulmonary bypass was highly increased in association with (1) a cardiac index less than 2.0 l/min-1/(m2)-1, (2) postoperative onset of atrial fibrillation, (3) emergency surgery, (4) need for vasopressors, (5) need for intraaortic balloon counterpulsation, and (6) need for early redo thoracotomy due to surgical complications. All patients with necrotic bowel disease had elevated serum lactate levels. Furthermore, cardiopulmonary bypass and aortic clamping times were significantly prolonged in patients who developed gastrointestinal complications. A number of predictive factors contribute to the development of gastrointestinal complications after cardiopulmonary bypass surgery. Knowledge of these factors may lead to earlier identification of patients at increased risk and may allow more efficient and earlier interventions to reduce mortality.

Computer-enhanced totally endoscopic sequential arterial coronary artery bypass

Minimally invasive coronary artery bypass grafting of the anterior wall using a left anterior small thoracotomy became a routine procedure within the last 3 years. The introduction of robotics into the cardiosurgical practice in 1998 has finally enabled totally endoscopic closed chest procedures. We report two patients with totally endoscopic left internal thoracic artery bypass grafting to the left anterior descending artery and the first diagonal branch in sequential arterial revascularization technique using the daVinci surgical system.

Mountaineering accidents in the European Alps: have the numbers increased in recent years?

OBJECTIVE

Media reports convey the impression that the incidence of fatal accidents in the European Alps has increased. Because more specific data are lacking, we analyzed available data from the mountain rescue services in Germany, Austria, southern Tirol, Zermatt/Switzerland, and Chamonix/France from 1987 until 1997.

METHODS

Information was gathered from the annual reports of the Austrian Mountain Rescue Service, the Swiss Alpine Club Rescue Station in Zermatt, the Mountain Rescue Service of the Southern Tirol Alpine Club, the Mountain Rescue Service of the Bavarian Red Cross, and the Department of Mountain Medicine and Traumatology from the Hospital in Chamonix.

RESULTS

Although the total number of rescue missions and injured alpinists increased significantly during the period, the number of fatalities retrieved during such rescue missions showed no significant increase.

CONCLUSIONS

Even taking into account the varying definitions of "mountain accident" used in these countries, available data from the analyzed areas of the European Alps do not demonstrate a drastic increase in the number of fatalities. In the future, data concerning mountain accidents in the European Alps should be monitored according to standard definitions and stored by the International Commission for Alpine Rescue.

Robotically enhanced totally endoscopic right internal thoracic coronary artery bypass to the right coronary artery

Computer-enhanced telemanipulation systems allow totally endoscopic coronary artery bypass grafting. This report demonstrates the feasibility of a coronary artery anastomosis between the right internal thoracic artery and the right coronary artery using the daVinci surgical system (Intuitive Surgical, Inc, Mountain View, CA).

Hemodynamics and gas exchange during carbon dioxide insufflation for totally endoscopic coronary artery bypass grafting

BACKGROUND

In addition to single-lung ventilation (SLV), positive-pressure CO2 insufflation is mandatory for totally endoscopic coronary artery bypass grafting. Studies on the effects of unilateral CO2 insufflation on hemodynamics produced controversial results, and bilateral insufflation has not been studied to our knowledge. The present study sought to investigate hemodynamics and gas exchange during unilateral and bilateral CO2 insufflation in patients who underwent totally endoscopic coronary artery bypass grafting.

METHODS

Eleven hemodynamic and gas exchange variables were monitored during 22 totally endoscopic coronary artery bypass grafting procedures with unilateral (n = 17) or bilateral (n = 5) CO2 insufflation at a pressure of 10 to 12 mm Hg. Data were obtained at baseline with double-lung ventilation, after institution of SLV, during insufflation, after cardiopulmonary bypass during SLV, and after return to double-lung ventilation.

RESULTS

Arterial oxygen tension decreased significantly during SLV, whereas the peak inspiratory pressure increased. In addition, central venous pressure and heart rate increased significantly during insufflation, but mean arterial pressure remained unchanged. Although the end-tidal CO2 pressure did not change, arterial carbon dioxide tension increased progressively to a maximum of 44.6 +/- 5.9 mm Hg during unilateral insufflation, and 55.7 +/- 14.6 mm Hg during bilateral insufflation (p < 0.05 versus baseline and between groups). Mixed venous oxygen saturation declined during SLV regardless of CO2 insufflation and recovered to baseline once double-lung ventilation was restarted. Left and right ventricular ejection fractions remained unaltered. No patient required inotropic or vasopressor support.

CONCLUSIONS

Carbon dioxide insufflation for totally endoscopic coronary artery bypass grafting with SLV had no adverse effects on hemodynamics. In contrast to a moderate increase of arterial carbon dioxide tension during unilateral insufflation, markedly elevated arterial carbon dioxide tension levels remain a cause of concern during bilateral insufflation.

Roboterassistierte, endoskopische Fundoplikatio nach Nissen bei Kindern

The robot device "da Vinci" represents the latest stage in laparoendoscopic surgery. We report the first two cases worldwide of endoscopic Nissen fundoplication with a telemanipulatory robot system in two children, aged 10 and 12 years. In addition to standard monitoring, we used invasive blood pressure monitoring during the 300 min periods of general anesthesia. Arterial blood gas samples were analyzed in short intervals. During surgery, which included 177 and 180 min periods of intraperitoneal insufflation of carbon dioxide, no significant changes of pH, PaO2, PaCO2, etCO2, heart rate, and mean arterial pressure were observed. Body temperature was maintained with an external warming blanket. Extubation was achieved immediately after the end of the operation, and both patients were discharged home on postoperative day 6. Robot-assisted techniques may possibly add significant progress and improvement to laparoendoscopic surgery. Nonetheless, we conclude that, despite our first encouraging results, potential risks of robot-assisted surgery have not yet been definitively defined. Therefore, patients are in need for intensive and even invasive monitoring, unless a larger number of patients has been studied.

Bedside percutaneous tracheostomy: clinical comparison of Griggs and Fantoni techniques

Elective tracheostomy is widely considered the preferred airway management of patients on long-term ventilation. In addition to open tracheostomy, a number of percutaneous procedures have been introduced during the last two decades, among them techniques according to Griggs (guidewire dilating forceps, or GWDF) and to Fantoni (translaryngeal tracheostomy, or TLT). The aim of the study was to evaluate these two techniques in terms of perioperative complications, risks, and benefits in critically ill patients. A series of 100 critically ill adult patients on long-term ventilation underwent elective percutaneous tracheostomy, either according to the Griggs (n = 50) or Fantoni (n = 50) technique. Tracheostomy was performed under general anesthesia at the patient's bedside. The mean (+/-SD) operating times were short, 9.2 +/- 3.9 minutes (TLT) and 4.8 +/- 3.7 minutes (GWDF) on average. Perioperative complications were noted in 4% of patients during either TLT or GWDF and included massive bleeding, mediastinal emphysema, posterior tracheal wall injury, and pretracheal placement of the tracheostomy tube. With regard to oxygenation, pre- and postoperative arterial oxygen tension divided by the fraction of inspired oxygen (PaO2/FiO2) ratios did not vary significantly, and no perioperative hypoxia was noted regardless of the technique used. We conclude that both TLT and GWDF represent attractive, safe alternatives to conventional tracheostomy or other percutaneous procedures if carefully performed by experienced physicians and under bronchoscopic control.

Induction of P-glycoprotein by rifampin increases intestinal secretion of talinolol in human beings: a new type of drug/drug interaction

BACKGROUND

P-Glycoprotein is an efflux pump in many epithelial cells with excretory function. It has been demonstrated that rifampin (INN, rifampicin) induces P-glycoprotein, particularly in the gut wall. We therefore hypothesized that rifampin affects pharmacokinetics of the P-glycoprotein substrate talinolol, a beta1-blocker without appreciable metabolic disposition but intense intestinal secretion in human beings.

METHODS

Pharmacokinetics of talinolol (a single dose of 30 mg administered intravenously or 100 mg administered orally for 7 days) and duodenal expression of the MDR1 gene product P-glycoprotein as assessed by reverse transcriptase-polymerase chain reaction of the MDR1-messenger ribonucleic acid, by immunohistochemistry and Western blot analysis were analyzed before and after coadministration of rifampin (600 mg per day for 9 days) in 8 male healthy volunteers (age 22 to 26 years).

RESULTS

During rifampin treatment, the areas under the curve of intravenous and oral talinolol were significantly lower (21% and 35%; P < .05). Treatment with rifampin resulted in a significantly increased expression of duodenal P-glycoprotein content 4.2-fold (2.9, 6.51) (Western blot) and messenger RNA was increased in six of the eight volunteers. P-Glycoprotein expression in biopsy specimens of gut mucosa correlated significantly with the systemic clearance of intravenous talinolol (rs = 0.74; P < .001).

CONCLUSIONS

Rifampin induces P-glycoprotein-mediated excretion of talinolol predominantly in the gut wall. Moreover, clearance of talinolol from the blood into the lumen of the gastrointestinal tract may be predicted by the individual intestinal P-glycoprotein expression. Thus we describe a new type of steady-state drug interaction affecting compounds that are subject to transport rather than metabolism.

Occupational exposure to nitrous oxide and desflurane during ear-nose-throat-surgery

PURPOSE

To determine occupational exposure of the anesthesiologist and surgeon to nitrous oxide and desflurane during general anesthesia for ear-nose-throat (ENT) surgery in children and adults.

METHODS

An observational clinical trial was performed in ten children (C) and ten adults (A). Tracheas were intubated, in adults, with cuffed tubes and in children with uncuffed tubes. The operating room was equipped with modern air conditioning and waste anesthetic gas scavengers. Gas samples were obtained during the operative procedure every 90 sec from the breathing zone of subjects. Time-weighted averages (TWA) over the time of exposure were calculated for nitrous oxide and desflurane.

RESULTS

Nitrous oxide TWAs for anesthesiologists were 0.41 +/- 0.23 ppm (A) and 1.20 +/- 0.32 ppm (C, P < 0.0001), and 2.24 +/- 1.93 ppm (A) and 5.30 +/- 0.60 ppm (C, P = 0.0001) for the surgeon who worked close to the patient's airway and thus had higher exposure (P < 0.05 [A], P < 0.0001 [C]). With regard to desflurane, the anesthesiologists' TWAs were 0.02 +/- 0.03 ppm for both adults and children. The surgeon was exposed to 0.21 +/- 0.24 ppm desflurane (A) and 0.30 +/- 0.14 ppm (C, P: n.s.). Although the surgeon's exposure was greater (P < 0.05 [A], P < 0.0001 [C]), the threshold limits of 25 ppm for nitrous oxide and 2 ppm for desflurane recommended by the National Institute of Occupational Safety and Health were not exceeded.

CONCLUSIONS

Under modern air conditioning, occupational exposure to inhalational anesthetics is low, and inhalational anesthesia is safe from the standpoint of modern workplace laws and health-care regulations.

Percutaneous tracheostomy: ciaglia blue rhino versus the basic ciaglia technique of percutaneous dilational tracheostomy

Percutaneous dilational tracheostomy (PDT), according to Ciaglia's technique described in 1985, has become the most popular technique for percutaneous tracheostomy and is demonstrably as safe as surgical tracheostomy. In 1999, an extensively modified technique of PDT was introduced, the Ciaglia Blue Rhino (CBR; Cook Critical Care, Bloomington, IL), that consists of one-step dilation by means of a curved dilator with hydrophilic coating. To compare CBR with the basic technique of PDT, we performed a prospective, randomized trial in 50 critically ill adults. Twenty-five of these patients had PDT, and 25 had CBR. Average operating times were <3 min for CBR (range: 50-360 s) and <7 min for PDT (range: 4-20 min; P<0.0001). Tracheostomy was successfully completed in all patients. When CBR was performed, 11 minor, nonlife-threatening complications were noted: nine fractures of tracheal cartilage and two short periods of intraoperative oxygen desaturation. During PDT, seven complications occurred, of which three were potentially life-threatening: two injuries to the posterior tracheal wall, one pneumothorax, two tracheal cartilage fractures (P< 0.05 vs CBR), one case of bleeding, and one short episode of intraoperative oxygen desaturation. Regardless of whether PDT or CBR was performed, oxygenation was not significantly affected, and there was no infection of the tracheostoma. Based on our data, we conclude that new CBR is more practicable than PDT. No life-threatening complications occurred during CBR.

IMPLICATIONS

To assess practicability and safety of the Ciaglia Blue Rhino (Cook Critical Care, Bloomington, IL)-an extensively modified technique of percutaneous dilatational tracheostomy-50 critically ill adults on long-term ventilation underwent either new Ciaglia Blue Rhino or percutaneous dilatational tracheostomy in a prospective, randomized clinical trial.

Early percutaneous tracheostomy after median sternotomy

OBJECTIVE

Tracheostomy offers significant advantages over endotracheal intubation in patients requiring long-term assisted ventilation. However, in patients who have undergone median sternotomy, it is believed that the danger of microbial contamination and consecutive infection of the sternal wound with microbes from the tracheostomy is high when conventional tracheostomy is performed. In contrast, percutaneous techniques are less likely to result in tracheostomy infection and thus bacterial contamination of neighboring structures. Nonetheless, to date there has been no prospective study confirming or disproving this assumption. Our study evaluated outcome after percutaneous tracheostomy in patients with a median sternotomy.

METHODS

A total of 144 cardiac surgical patients had elective percutaneous tracheostomy at the bedside until postoperative day 14, with 4 different techniques. Systematic microbiologic monitoring of the sternal and tracheal wounds was used.

RESULTS

In 13 patients sternal wound infection was suspected, but was confirmed in only 4 (2.8%) patients who actually showed microbial contamination of the sternum. In 2 of these patients, the identified microbes were not identical to those cultured from the trachea. The other 2 patients had sternal and tracheal cultures positive for methicillin-resistant Staphylococcus aureus. Cross-contamination of the sternotomy with microbes from the patient's airways was therefore ruled out. No patient had clinical signs of tracheostomy infection. Likewise, there were no cases of mediastinitis.

CONCLUSIONS

On the basis of our data, we conclude that cross-contamination of the sternal wound with microbes from the trachea is not a problem. Elective percutaneous tracheostomy is safe, even if performed during the first 14 days after median sternotomy.

[Special anesthesiologic features in minimally invasive heart surgery]

When heart-lung machines made extracorporeal circulation possible in the fifties, cardiac surgeons gained virtually unrestricted access to the resting, motionless heart. Valve repair and reconstruction, in particular, made great progress as a result of extracorporeal circulation. While the distinct advantages of extracorporeal circulation for cardiosurgery remain undisputed, awareness of the significant perioperative risks of extracorporeal circulation for the patient has been increasing in recent years. This has lead to an interest in alternative cardiosurgical techniques avoiding extracorporeal circulation. Inspired by minimally-invasive procedures in abdominal surgery, cardiosurgical instruments as well as surgical techniques of access to the heart and large thoracic vessels were systematically modified leading to today's minimally-invasive cardiosurgical procedures such as off-pump coronary artery bypass grafting on the beating heart. Similarly, in the field of cardiac valve repair, new cannulation techniques for instituting extracorporeal circulation make median sternotomy unnecessary. The developments described above have lead to the recent introduction of robot-assisted techniques with or without extracorporeal circulation, which are expected to make possible in the near future the performance of the whole range of cardiosurgical procedures with minimal surgical trauma. The introduction of the new techniques has changed the intraoperative responsibilities of the anesthesiologist. The present article will therefore describe both the new surgical techniques as well as the new tasks required of the anesthesiologist, in particular with regard to cannulation and monitoring. Since a number of terms in minimally-invasive cardiosurgery are not precisely defined, a clear description of the various surgical techniques is also provided.

Translaryngeal tracheostomy in highly unstable patients

Percutaneous tracheostomy is a widely accepted and commonly performed technique for attaining long-term airway access in critically ill patients. However, severe respiratory failure and coagulopathy are relative contraindications for these procedures. We describe two patients with severe respiratory failure and inhibitor-complicated haemophilia A who underwent elective percutaneous tracheostomy performed translaryngeally, using the new Fantoni technique. Apart from two minor bleeding episodes in the haemophilic patient which were controlled promptly, no other complications occurred. If certain precautions are observed carefully, we believe that translaryngeal tracheostomy is a procedure which is superior to other percutaneous techniques and safe even in patients with severe respiratory failure and coagulopathy.

Oral bioavailability of digoxin is enhanced by talinolol: evidence for involvement of intestinal P-glycoprotein

OBJECTIVE

Recent data indicated that disposition of oral digoxin is modulated by intestinal P-glycoprotein. The cardioselective beta-blocker talinolol has been described to be secreted by way of P-glycoprotein into the lumen of the gastrointestinal tract after oral and intravenous administration. We therefore hypothesized that coadministration of digoxin and talinolol may lead to a drug-drug interaction based on a competition for intestinal P-glycoprotein.

METHODS

Pharmacokinetics of digoxin (0.5 mg orally), talinolol (30 mg intravenously and 100 mg orally), and digoxin plus talinolol orally, as well as digoxin plus talinolol intravenously, were assessed in five male and five female healthy volunteers (age range, 23 to 30 years; body weight, 60 to 95 kg) in a changeover study with at least a 7-day washout period. Digoxin and talinolol were analyzed by fluorescence polarization immunoassay and HPLC, respectively.

RESULTS

Oral coadministration of 100 mg talinolol increased the area under the concentration-time curve (AUC) from 0 to 6 hours and the AUC from 0 to 72 hours of digoxin significantly by 18% and 23%, respectively (5.85+/-1.49 versus 7.22+/-1.29 ng x h/mL and 23.0+/-3.3 versus 27.1+/-3.7 ng x h/mL, for both P<.05) and the maximum serum levels by 45%. Renal clearance and half-life of digoxin remained unchanged. Coinfusion of 30 mg talinolol with oral digoxin had no significant effects on digoxin pharmacokinetics. Digoxin did not affect the disposition of talinolol after both oral and intravenous administration.

CONCLUSION

We observed a significantly increased bioavailability of digoxin with oral coadministration of talinolol, which is most likely caused by competition for intestinal P-glycoprotein.

[Exposure of anesthetists to sevoflurane and nitrous oxide during inhalation anesthesia induction in pediatric anesthesia]

Inhalational mask induction with nitrous oxide and sevoflurane in young children is an appropriate alternative to intravenous induction and is considered safe and of rapid onset. Disadvantages of this technique are environmental pollution and occupational exposure to the inhalation agents used. Moreover, the potential health hazards are not yet completely clear. The purpose of the present study was to examine the anaesthesiologist's occupational exposure to nitrous oxide and sevoflurane in paediatric anaesthesia and mask induction. Twenty children underwent inhalational induction with nitrous oxide and sevoflurane in the operating theatre (air exchange rate 20.2/h, anaesthetic waste gas scavenger 40 l/min). Anaesthesia was maintained with the same agents. Air samples were taken from the edge of the anaesthesiologist's mouth continuously every 90 seconds, and trace concentrations of nitrous oxide and sevoflurane were analyzed with a direct reading infrared spectrometer (Brüel & Kjaer 1302, Denmark). Measurements taken during anaesthesia showed an increase in the concentrations of the anaesthetics used, but these were low. The highest mean concentrations occurred during induction (3.35 +/- 4.23 ppm for sevoflurane and 37.09 +/- 11.65 ppm for nitrous oxide). The overall peak levels measured were 6.31 +/- 4.23 ppm for sevoflurane and 68.78 +/- 40.79 ppm for nitrous oxide. Though the induction period was short compared to the whole length of anaesthesia, its impact on the overall waste gas exposure was 46.3% for sevoflurane (nitrous oxide 40.6%). Nonetheless, applicable German health law regulations were never infringed. The trace concentrations measured during inhalational mask induction and maintenance of anaesthesia were very low. With regard to modern workplace laws and health care regulations, gaseous induction in paediatric anaesthesia does not threaten the personnel's health.

Translaryngeal tracheostomy: two modified techniques versus the basic technique--early experience in 75 critically ill adults

OBJECTIVES

Elective tracheostomy is an established procedure in the management of ICU patients on long-term ventilation. In addition, percutaneous tracheostomy techniques are increasingly being used. In 1997, Fantoni's translaryngeal technique (TLT), another minimally invasive procedure, was introduced. While clinical studies of TLT showed that the technique is safe and can be performed rapidly, technical difficulties which sometimes led to prolonged operating times were also noted. Our study compared the basic TLT technique to a modified TLT approach and to TLT performed with the manufacturer's new, improved "Straight Cannula" set. Twenty-five patients were enrolled in each group, and the advantages and disadvantages of the respective techniques were evaluated.

SETTING

Surgical ICU of a university hospital.

PATIENTS

Seventy-five adult, surgical intensive care patients.

MEASUREMENTS AND RESULTS

Average operating times with the modified TLT techniques were significantly shorter, 4 and 5 min respectively, as compared to 11 min for the basic TLT technique. Initially, use of the new, improved TLT set resulted in a complete passage of the tracheal cannula in two patients; uneventful Griggs's tracheostomy was performed instead. Regardless of the technique used, no other perioperative complications were noted and the perioperative gas exchange remained unaffected by the tracheostomy procedure.

CONCLUSIONS

The modified TLT procedures are safer and more readily performed than the basic technique. Difficulty in the retrograde passage of the guide wire was seen only occasionally with the modified techniques. Based on our data we conclude that the modified techniques are superior to the basic technique and represent significant progress in TLT.

[Ciaglia blue rhino: a modified technique for percutaneous dilatation tracheostomy. Technique and early clinical results]

OBJECTIVE

Elective tracheostomy has become an established treatment modality in modern intensive care medicine, and the number of percutaneously performed tracheostomies is steadily increasing. The Ciaglia Blue Rhino (CBR) represents another percutaneous technique in which the tracheostoma is formed by one-step dilation. Our study presents the technique itself and the early clinical experiences.

METHODS

In 20 adult patients on long-term ventilation, CBR was done. After puncture of the trachea in typical manner, dilation of the tracheostoma was achieved in one single step by means of a curved dilator with a special hydrophilic coating. Then, the tracheostomy tube was inserted over a curved loading dilator. Practicability and safety were determined as well as gas exchange during the procedure by means of arterial blood gas samples.

RESULTS

As a result of the dilator's hydrophilic coating, dilation of the tracheostoma was rapidly achieved within 152 +/- 22 s, virtually free from resistance of the trachea or the cervical tissues. Complications such as bleeding, aspiration or postoperative infection of the stoma were not noted in any of our patients. Fractures of isolated tracheal cartilage rings were seen in 5 patients, however, no therapeutic intervention was necessary. In terms of perioperative gas exchange, pre- and postoperative levels of FiO2, PaO2, PaCO2 and the oxygenation index (PaO2/FiO2) did not change significantly.

CONCLUSIONS

Based on our early clinical experience, Ciaglia Blue Rhino represents a new method that may combine the typical advantages of each of the other techniques for percutaneous tracheostomy (i.e. Ciaglia, Griggs, Fantoni) in one single technique. This method is distinguished by a high level of safety and practicability. However, further comparative trials need to be done before a definitive judgement can be made.