Comparison of breathing tube connectors during invasive bronchial procedures.

Bronchoscopy and bronchial suctioning during intra-operative artificial ventilation often causes leakage from the ventilation circuit with a decrease in ventilatory parameters and possible workplace contamination with anaesthetic gases. Different connectors have been developed to reduce gas leakage. We evaluated the following connectors : VBM 2 mm, 3 mm and 5 mm, Bodai Suction-Safe, Bodai Bronch-Safe and Bodai Trach-Safe, as well as the BE 105-7, BE 105-8 and SH 7-45. Invasive bronchial instruments (catheters, bronchoscopes and bronchial blockers) with 1.67-7.33 mm diameter were used. Pressure-controlled ventilation was performed on a test lung using a ventilator. Sevoflurane concentration in the room was measured 0.2 and 1.5 m from the connector using a photo-acoustic infrared-spectroscope. The VBM connectors caused the least gas leak and ensured stability of ventilation parameters even at peak pressures when combined with smaller instruments. With instruments > 6 mm, BE 105-7, BE 105-8 and SH 7-45 connectors performed best. The Bodai connectors showed a reduced ability to prevent leakage and to keep ventilatory parameters stable. All connectors, excluding the Bodai Trach-Safe, prevented exposure to anaesthetic gases beyond the current safety recommendations when combined with the fitting instruments. The connectors showed different ranges of tightness, equivalent to different ranges of compatibility with the instruments used.

Bleeding management with fibrinogen concentrate targeting a high-normal plasma fibrinogen level: a pilot study.

BACKGROUND: Bleeding diathesis after aortic valve operation and ascending aorta replacement (AV-AA) is managed with fresh-frozen plasma (FFP) and platelet concentrates. The aim was to compare haemostatic effects of conventional transfusion management and FIBTEM (thromboelastometry test)-guided fibrinogen concentrate administration. METHODS: A blood products transfusion algorithm was developed using retrospective data from 42 elective patients (Group A). Two units of platelet concentrate were transfused after cardiopulmonary bypass, followed by 4 u of FFP if bleeding persisted, if platelet count was < or =100 x 10(3) microl(-1) when removing the aortic clamp, and vice versa if platelet count was >100 x 10(3) microl(-1). The trigger for each therapy step was > or =60 g blood absorbed from the mediastinal wound area by dry swabs in 5 min. Assignment to two prospective groups was neither randomized nor blinded; Group B (n=5) was treated according to the algorithm, Group C (n=10) received fibrinogen concentrate (Haemocomplettan P/Riastap, CSL Behring, Marburg, Germany) before the algorithm-based therapy. RESULTS: A mean of 5.7 (0.7) g fibrinogen concentrate decreased blood loss to below the transfusion trigger level in all Group C patients. Group C had reduced transfusion [mean 0.7 (range 0-4) u vs 8.5 (5.3) in Group A and 8.2 (2.3) in Group B] and reduced postoperative bleeding [366 (199) ml vs 793 (560) in Group A and 716 (219) in Group B]. CONCLUSIONS: In this pilot study, FIBTEM-guided fibrinogen concentrate administration was associated with reduced transfusion requirements and 24 h postoperative bleeding in patients undergoing AV-AA.

Platelet concentrates transfusion in cardiac surgery and platelet function assessment by multiple electrode aggregometry.

BACKGROUND: Platelet dysfunction contributes to the pathophysiology of bleeding complications during and after cardiac surgery. In most surgical institutions, no peri-operative point-of-care monitoring of platelet function is used. We evaluated the usefulness of the Multiplate platelet function analyser based on impedance aggregometry for identifying groups of patients at a high risk of transfusion of platelet concentrates (PC). METHODS: Platelet function parameters were determined in 60 patients before and after routine cardiac surgery. Impedance aggregometry measurements were performed on Multiplate using ADP (ADPtest), collagen (COLtest) and thrombin receptor activating peptide (TRAPtest) as platelet activators. The correlations between the aggregometry results and the transfusion of PC were calculated. The results of the aggregation tests were also divided into tertiles and the differences in PC transfusion between the low and the high tertile were assessed. RESULTS: Low aggregometry delimited groups of patients with significantly higher PC transfusion. In the receiver operating characteristic curve, low pre-operative aggregation in the ADPtest identified patients with high total transfusion of PC (area under the curve 0.74, P=0.001), while the ADPtest performed at the end of the operation identified patients with high PC transfusion on the intensive care unit (ICU) (area under the curve 0.76, P=0.002). CONCLUSIONS: Near-patient platelet aggregation may allow the identification of patients with enhanced risk of PC transfusion, both pre-operatively and upon arrival on the ICU.

Role of endotoxin in the pathogenesis of critical illness polyneuropathy.

Critical illness polyneuropathy (CIP) occurs in association with sepsis and multiple organ failure; however, little is known about the pathomechanisms of CIP and its therapy. In order to determine the parameters which interfere with development of CIP, electrophysiological investigations of peripheral nerves and biochemical measures were correlated to each other. The present study includes 20 consecutive patients in an intensive care unit developing severe sepsis or septic shock. Nerve conduction studies and electromyography were performed with occurring sepsis (day 1, 7, 14) and neurophysiological parameters were correlated with biochemical measures, especially indicators of infection and inflammation. It was found that all patients developed neurophysiological signs of axonal motor polyneuropathy. There was a significant correlation between serum concentrations of endotoxin and interleukin-2 receptors (IL2-R) and reduction of the amplitude of the compound motor action potentials. Other clinical and biochemical parameters showed no significant correlations with neurophysiological data. This finding apparently indicates that endotoxin damages nerve axons directly or indirectly, e.g. by activation of inflammatory cascades (IL2-R). Endotoxin appears to be an essential factor in the pathogenesis of CIP in sepsis, and therapeutic options neutralizing endotoxin may prevent development of CIP.

Endocrine stress response and inflammatory activation during CABG surgery. A randomized trial comparing remifentanil infusion to intermittent fentanyl.

BACKGROUND AND OBJECTIVE: Our aim was to compare a continuous infusion of remifentanil with intermittent boluses of fentanyl as regards the perioperative hormonal stress response and inflammatory activation in coronary artery bypass graft patients under sevoflurane-based anaesthesia. METHODS: In all, 42 patients undergoing coronary artery bypass grafting with cardiopulmonary bypass were prospectively randomized to a fentanyl group (n = 21, total fentanyl dose 2.6 +/- 0.3 mg), or a remifentanil group (n = 21, infusion rate 0.25 microg kg(-1) min(-1)). Haemodynamics, plasma levels of epinephrine, norepinephrine, antidiuretic hormone, adrenocorticotropic hormone, cortisol, complement activation (C3a, C5b-9), interleukin (IL)-6, IL-8 and tumour necrosis factor-alpha were measured at T1: baseline, T2: intubation, T3: sternotomy, T4: 30 min on cardiopulmonary bypass, T5: end of surgery and T6: 8 h postoperatively. Troponin T and creatine kinase-MB were measured postoperatively. RESULTS: Patients in the remifentanil group were extubated significantly earlier than fentanyl patients (240 +/- 182 min vs. 418 +/- 212 min, P = 0.006). Stress hormones 30 min after start of cardiopulmonary bypass showed higher values in the fentanyl group compared to the remifentanil group (antidiuretic hormone (ADH): 39.94 +/- 30.98 vs. 11.7 +/- 22.8 pg mL(-1), P = 0.002; adrenocorticotropic hormone: 111.5 +/- 116.8 vs. 21.81 +/- 24.71 pg mL(-1), P = 0.01; cortisol 185 +/- 86 vs. 131 +/- 82 ng mL(-1), P = 0.04). The interleukins were significantly higher at some perioperative time points in the fentanyl group compared to the remifentanil group (tumour necrosis factor: T5: 3.57 vs. 2.37; IL-6: T5: 4.62 vs. 3.73; and IL-8: T5: 4.43 vs. 2.65 and T6: 2.61 vs. 1.13). However, cardiopulmonary bypass times and aortic cross-clamp times were longer in the fentanyl group, which may to some extent account for the differences. CONCLUSIONS: The perioperative endocrine stress response was attenuated in patients supplemented with continuous remifentanil infusion as compared to intermittent fentanyl.

[Are there pulmonary vascular or respiratory effects of prostaglandin vehicles (ethanol, glycine buffer) after intravenous infusion or inhalation?]. / Verursacht die Infusion oder Inhalation von Prostaglandin-Trägerlösungen (Athanol, Glycin-Puffer) pulmonalvaskuläre oder respiratorische Effekte?

BACKGROUND: Infusion or inhalation of prostaglandins PGE1 and PGI2 is used to reduce vascular resistance. PGE1 and PGI2 are dissolved in ethanol and glycine buffer, respectively. Each vehicle may cause dose-dependent haemodynamic and respiratory side effects. This study was performed to examine the role of low-dose ethanol and glycine buffer as used for the infusion and inhalation of PGE1 and PGI2. METHODS: Two groups of pigs (ethanol and glycine group, n = 9 each) were anaesthetised and ventilated mechanically. Ethanol was given at 0.14 mg/kg/min by infusion and 0.12 mg/kg/min as aerosol, glycine buffer was infused at 3.8 microg/kg/min and inhaled at 3.1 microg/kg/min, respectively. Haemodynamic and respiratory data were recorded before and after application. RESULTS: Neither infusion nor inhalation of ethanol or glycine buffer caused significant changes in systemic and pulmonary haemodynamics, right heart function, oxygenation or ventilation. CONCLUSIONS: The effect of inhaled or intravenously infused PGE1 and PGI2 is not influenced by their preparations containing ethanol or glycine buffer.

[Evaluation of blood and breath alcohol measurement in patients with hepatocellular carcinoma during procedures in intubated patients with percutaneous ethanol instillation]. / Vergleich von Blut- und Atemalkoholkonzentrationen während der perkutanen Athanolinstillationstherapie (PEIT) bei intubierten Patienten mit hepatozellulärem Karzinom.

The accuracy of breath alcohol measurements in intubated patients with assisted ventilation was evaluated. The breath alcohol concentration was measured in 24 patients undergoing percutaneous alcohol injection therapy for hepatocellular carcinoma with Alcotest 7410 med, from Dräger, Germany. The blood ethanol concentrations (BACs) were determined in each blood serum applying the German forensic criteria standard, namely, two alcohol dehydrogenase (ADH) and two gas chromatography (GC) measurements. The blood alcohol concentrations were between 0.07 and 1.51 per thousand in the central venous samples and 0.02-1.66 per thousand in the arterial samples. An excellent correlation between both the venous and arterial blood alcohol concentrations (r2=0.94), as well as between the breath alcohol concentrations and the venous (r2=0.84) or arterial alcohol concentration (r2=0.89), p<0.01 for both parameters was revealed. Determination of breath alcohol concentration using the Alcotest in intubated patients is reliable and reflects the blood alcohol values.

Pressure-controlled versus volume-controlled one-lung ventilation for MIDCAB.

One-lung ventilation is limited by hypoventilation and hypoxemia because of increasing airway pressure and intrapulmonary shunt. Previous clinical studies compared pressure-controlled versus volume-controlled ventilation during one-lung ventilation in patients with pre-existing pulmonary disease. We studied 50 patients undergoing thoracotomy and one-lung ventilation because of cardiovascular disease. After two-lung ventilation with volume-controlled ventilation, patients were divided randomly into two groups. In one group, ventilation was switched to pressure-controlled ventilation after starting one-lung ventilation. In the other group, volume-controlled ventilation was continued. Parameters of ventilation, pulmonary function and systemic and pulmonary hemodynamics were recorded. We observed, that peak airway pressure, dead space ventilation and arterial carbon dioxide partial pressure were significantly higher during volume-controlled ventilation. After one-lung ventilation patients with pressure controlled ventilation had lower alveolar-arterial oxygen tension difference and a higher arterial oxygen partial pressure with significant differences for those patients in the intensive care unit. We conclude that pressure-controlled ventilation may be useful to improve gas exchange and alveolar recruitment during one lung ventilation.

Cardiopulmonary effects of intravenous prostaglandin E1 during experimental one-lung ventilation.

BACKGROUND: One-lung ventilation greatly improves operating conditions during thoracic surgery. Serious disadvantages of one-lung ventilation are hypoxaemia and increased pulmonary vascular resistance. Prostaglandins, like prostaglandin I2 (PGI2), are potent pulmonary vasodilators but may also influence venous admixture and systemic circulation. Since the lung is capable of extensive degradation of prostaglandin E1 (PGE1) but not of PGI2, PGE1 might affect systemic circulation to a lesser degree. Hence, we studied the effects of intravenous PGE1 on systemic and pulmonary circulation and on oxygenation during one-lung ventilation. METHODS: Lateral thoracotomy and cross-clamping of the left main stem bronchus was performed in twelve anaesthetised and ventilated pigs. Animals were cannulated with arterial, central venous and fast response thermodilution pulmonary artery catheters for haemodynamic measurements. PGE1 was administered with infusion rates of 25, 50, and 100 ng x kg (-1) x min (-1) during one-lung ventilation. RESULTS: All doses of PGE1 significantly decreased pulmonary vascular resistance and mean pulmonary artery pressure. However, a comparable significant reduction in systemic vascular resistance and mean arterial pressure was found. Arterial oxygen tension and venous admixture showed a slight but significant deterioration. Oxygen delivery remained unchanged or increased since the cardiac index increased. CONCLUSION: During one-lung ventilation in the pig, infusion of PGE1 significantly decreased pulmonary vascular resistance and pulmonary artery pressure but failed to achieve selective pulmonary vasodilation.

Esomeprazole for the prevention of postoperative nausea and vomiting. A randomized, placebo-controlled trial.

BACKGROUND: Postoperative nausea and vomiting still represents a major problem after surgery. Although risk factors for postoperative nausea and vomiting and procedures to reduce postoperative nausea and vomiting have been described, the incidence of postoperative nausea and vomiting remains high. The aim of the present study was to investigate the potential role of the proton pump inhibitor esomeprazole to reduce postoperative nausea and vomiting after elective surgery. METHODS: In a randomized, double-blind trial, ASA I-III patients at high risk for postoperative nausea and vomiting received esomeprazole tablets 3 x 40 mg or matching placebo the evening before surgery, 2 h preoperatively and 24 h postoperatively. Total intravenous anaesthesia with propofol and remifentanil without nitrous oxide (FiO2 0.5) was used. Patients were interviewed using a standardized postoperative nausea and vomiting questionnaire at discharge from the post-anaesthesia care unit, 6 h and 24 h later. The severity of nausea was estimated on a 0-100 point numerical scale (0 = no nausea, 100 = maximum nausea). RESULTS: The incidence of vomiting was similar in the esomeprazole (n = 45) and the placebo (n = 48) groups (64.4% vs. 60.5%, P > 0.05). The average nausea score was 17.8 with esomeprazole and was 18.7 with placebo (P > 0.05). Only 24.7% of all patients (esomeprazole 24.4%, placebo 25.0%) did not experience any nausea or vomiting. CONCLUSION: There is no evidence that prophylactic esomeprazole reduces the incidence of postoperative nausea and vomiting or the degree of postoperative nausea.

Postoperative nausea and vomiting (PONV) : usefulness of the Apfel-score for identification of high risk patients for PONV.

OBJECTIVE: Postoperative nausea and vomiting (PONV) still represent an important problem in surgery. Treatment and prevention of PONV requires accurate risk stratification. The simplified Apfel-score includes the four factors female gender, no smoking, postoperative use of opioides and previous PONV or motion-sickness in patients' history. Each of these risk factors is supposed to elevate the PONV-incidence about 20%. The aim of the study was to validate this clinical risk assessment score in patients with high risk for PONV. METHODS: In a prospective study 93 patients with high risk preoperative score for PONV (Apfel Score III and IV) were analyzed. Patients and nurses were interviewed using a standardized questionnaire at the time of discharge from the post-anesthesia care unit (PACU) as well as 6 hours and 24 hours after admission to the PACU. General anaesthesia was applied as total intravenous anaesthesia (TIVA) with mivacurium, propofol and remifentanil (no nitrous oxide / FI 02 0.5) RESULTS: In the group with Apfel score III PONV occurred in 59.7% of patients and in the Apfel score group IV in 91.3% of all patients. The incidence of PONV corresponds to the predicted values of 60% for Apfel III and 80% for Apfel IV although the use of TIVA should have reduced the incidence of PONV about 26%. This apparent overestimation could be explained by the frequent questioning of patients and nurses for PONV leading to assessment of very minor symptoms. CONCLUSION: The Apfel-score is a useful and simple tool for stratification of patients with high risk for PONV.

The laryngeal tube for difficult airway management: a prospective investigation in patients with pharyngeal and laryngeal tumours.

BACKGROUND AND OBJECTIVE: Since the introduction of the laryngeal mask into clinical practice, various additional supraglottic ventilatory devices have been developed. Although it has been demonstrated that the laryngeal tube is an effective airway device during positive pressure ventilation no clinical study has been performed thus far regarding its use in patients with predicted ventilation and intubation difficulties. METHODS: The aim of this study was to prospectively evaluate the use of the laryngeal tube for temporary oxygenation and ventilation in adult patients with supraglottic airway tumours scheduled to undergo a pharyngeal-laryngeal oesophagoscopy and bronchoscopy under general anaesthesia. In addition to our standard airway management with face mask ventilation and rigid bronchoscopy, all patients were temporarily ventilated with an laryngeal tube. Also, in patients requiring laryngeal biopsies, endotracheal intubation was performed with a 6.0 mm microlaryngeal tracheal tube. Minute ventilation volumes, tidal volumes, ventilation pressures, end-expiratory CO2 concentration, oxygen saturation and arterial blood gas samples were measured. RESULTS: From 54 enrolled patients only patients with relevant tumour masses were evaluated (n = 23). Mask ventilation was performed without difficulty in 15 of 23 patients. Mechanical ventilation with the laryngeal tube was possible in 22 of 23 patients with an audible leak present in three. Conventional endotracheal intubation was successfully performed in 19 of 23 patients. During face mask ventilation, minute volume, tidal volume, ventilation pressure, end-tidal CO2, oxygen saturation and arterial PO2 were significantly lower and PCO2 significantly higher (P < 0.05, paired t-test). No statistically significant differences were noted between the laryngeal tube and the microlaryngeal tracheal tube. CONCLUSIONS: The possibility of difficult ventilation and intubation must always be considered, in patients with supraglottic airway tumours. In these cases, the laryngeal tube can be considered for routine airway management and may be useful in the 'cannot-intubate' situation although difficulties should be anticipated in patients with previous irradiation, specifically of the throat area.

[Examination of a new tube connector concerning the ventilation-leakage during intraoperative bronchoskopy and bronchal suction]. / Dichtigkeitsprüfung einer neuen Tubuskonnektorschleuse zur intraoperativen Bronchoskopie und Absaugung.

BACKGROUND AND OBJECTIVE: Intra-operative bronchial suction and bronchoscopy regularly diminishes ventilation pressures and volumes and causes a leakage of narcotic gases. This study was undertaken to compare the influence of a newly-developed connecting tube with check valve on these problems. METHODS: Examinations were carried out in a pressure controlled test lung with ventilation pressures between 5 and 50 mbar. Usual tube connectors and newly developed connectors with check valve were examined with respect to ventilation pressures, ventilation volumes, and leakage before and after insertion of suction catheters and bronchoscopes. RESULTS: Using normal connectors, ventilation pressures and volumes collapsed even at lowest expiratory pressures, and significant leakage occurred. The insertion of catheters or bronchoscopes had only little beneficial effects. In contrast, the new connectors with check valve showed only small leakage, even at high ventilation pressures. CONCLUSION: The new tube connectors with check valve allow intra-operative suction and bronchoscopy under constant ventilation parameters with minor leakage of anaesthetic gas.

[Assessment of anesthesia methods in ophthalmologic surgery by patients, surgeons, and anesthesiologists]. / Bewertung von Narkoseverfahren in der Ophthalmochirurgie durch Patienten, Operateur und Anästhesisten.

BACKGROUND: The purpose of this study was to evaluate anesthesia methods in ophthalmic surgery in elderly people assessed by patients, surgeon, and anesthesiologist using subjective rating scales. PATIENTS AND METHODS: In a prospective, randomized study we compared in 52 (26 vs 26) elderly patients (ASA II and III, mean age 78.7+/-8.6 years) undergoing a cataract operation the satisfaction perceived by patients, surgeons, and anesthesiologists in relation to anesthesia methods [intravenous anesthesia (TIVA) vs balanced anesthesia (BA)] based on a score from 1=best to 6=worse. RESULTS: Patient satisfaction was better in the TIVA group (1.65) than in the patients treated with BA (2.57), p<0.001. Surgeons perceived no difference (BA 1.15/TIVA 1.07). Anesthesiologists preferred TIVA (TIVA 1.5/BA 3.23), p<0.001. CONCLUSION: In this study patients and anesthesiologists preferred TIVA. There was no difference between TIVA and BA as seen by the surgeon.

Reduction of catheter-related infections in neutropenic patients: a prospective controlled randomized trial using a chlorhexidine and silver sulfadiazine-impregnated central venous catheter.

Antiseptic coating of intravascular catheters may be an effective means of decreasing catheter-related colonization and subsequent infection. The purpose of this study was to assess the efficacy of chlorhexidine and silver sulfadiazine (CH-SS)-impregnated central venous catheters (CVCs) to prevent catheter-related colonization and infection in patients with hematological malignancies who were subjected to intensive chemotherapy and suffered from severe and sustained neutropenia. Proven CVC-related bloodstream infection (BSI) was defined as the isolation of the same species from peripheral blood culture and CVC tip (Maki technique). This randomized, prospective clinical trial was carried out in 106 patients and compared catheter-related colonization and BSI using a CH-SS-impregnated CVC (n=51) to a control arm using a standard uncoated triple-lumen CVC (n=55). Patients were treated for acute leukemia (n=89), non-Hodgkin's lymphoma (n=10), and multiple myeloma (n=7). Study groups were balanced regarding to age, sex, underlying diseases, insertion site, and duration of neutropenia. The CVCs were in situ a mean of 14.3+/-8.2 days (mean+/-SD) in the study group versus 16.6+/-9.7 days in the control arm. Catheter-related colonization was observed less frequently in the study group (five vs nine patients; p=0.035). CVC-related BSI were significantly less frequent in the study group (one vs eight patients; p=0.02). In summary, in patients with severe neutropenia, CH-SS-impregnated CVCs yield a significant antibacterial effect resulting in a significantly lower rate of catheter-related colonization as well as CVC-related BSI.

[Excessive blood loss after abdominal hysterectomy -- use of recombinant factor VIIa]. / Massive Blutung nach Hysterektomie -- Einsatz von rekombinantem Faktor VIIa.

MEDICAL HISTORY: A 38-yr-old woman suffered from excessive blood loss after elective removal of the uterus because of a leiomyoma. The surgical attempt to stop the bleeding failed. The laboratory evaluation before surgery showed normal coagulation parameters (aPTT 23.4 sec, TPZ > 100 %, platelet count 267 000/microl). DEVELOPMENT: Despite treatment with the plasminogen activator inhibitor Tranexamic Acid (2 x 500 mg) and 10 units of concentrated platelets as well as 31 units of fresh frozen plasma and 31 units of red blood cell concentrates the bleeding continued. Reaching an cumulative blood loss of 15 000 ml the patient developed ventricular fibrillation necessitating cardiac resuscitation including defibrillation and application of epinephrine 7 mg. At this point systolic blood pressure decreased from 90 to 70 mm Hg, the core temperature was 31,9 degrees C. After successful resuscitation (systolic blood-pressure 90 mm Hg after 15 min) the bleeding started again with a blood loss of 2000 ml requiring 3 units of fresh frozen plasma and 3 red cell concentrates Use of recombinant activated Factor VII (r.FVIIa): 6 mg (300 KiU) r.FVIIa have been applied (92 microg/kgKG [4.6 KiE/kg]). Within 10 minutes the bleeding stopped. More transfusions were not necessary. The patient left the intensive care unit 8 days after the operation without neurological deficit. CONCLUSION: The use of recombinant Factor VIIa may stop excessive haemorrhage, even if the cause is unknown.