The effects of different sampling techniques on peripheral post mortem tryptase levels: a recommended sampling method.

Different sampling techniques can impact on post mortem tryptase levels. A previous study demonstrated significantly lower femoral post mortem total tryptase levels in samples collected via transcutaneous aspiration compared with directly sampling during internal examination. However, an outlier with high tryptase level was noted in one transcutaneous aspiration sample. This 6-month prospective study compared total post mortem tryptase levels between 21 paired aspirated venous and arterial femoral blood samples, and 19 paired aspirated and cutdown femoral venous blood samples in non-anaphylactic deaths only. No statistical differences were demonstrated between the different sampling methods. However, four outlier cases with higher tryptase levels in aspirated arterial and femoral cutdown samples compared with aspirated venous femoral samples were noted. The reasons for the outliers may be due to the bloods collected from these two methods being contaminated by central arterial and venous blood with high tryptase levels respectively. None of the aspirated venous femoral post mortem tryptase levels were above recognized post mortem tryptase cutoff to diagnose anaphylaxis. This study recommends aspirating blood samples from a clamped femoral/external iliac vein for post mortem tryptase analysis should be defined as the gold standard. Further study using the recommended sampling method on post mortem tryptase levels in non-anaphylactic and anaphylactic cases is warranted.

A new oxygenator change-out system and procedure.

Official reports relate that, in the US, one patient/month dies as a result of the emergency oxygenator change-out procedure, and the permanent injury of some patients is the result of current oxygenator change-out procedures or oxygenator failures, both in extracorporeal circulation (ECC) and extracorporeal membrane oxygenation (ECMO). The aim of this article is to evaluate a new system and procedure, dedicated to oxygenator change-out, represented by two three-way stopcocks inserted in the ECC line in use. A dedicated back-up oxygenator and circuit can be easily primed and connected to the dedicated connector on the stopcocks, then blood flow is diverted to the new oxygenator without interruption of the ECC. Tests performed showed that oxygenator change-out can be completed by perfusionists in 62.13 +/- 11.12 sec. Results obtained show that the new system and procedure allows fast, safe and reproducible oxygenator change-out without interruption of the ECC.

The A-Med right heart support for off-pump coronary artery bypass grafting.

BACKGROUND: Off-pump coronary artery bypass grafting (OPCAB) presents several advantages but, mainly due to the impaired diastolic filling of the right ventricle, the displacement of the heart can cause hemodynamic instability. The aim of this study was to investigate the possible role of the A-Med right heart support during OPCAB. METHODS: We report our early experience with the A-Med system (A-Med, West Sacramento, CA, USA) during OPCAB. The system consists of a coaxial cannula, a microcentrifugal pump and a control console. The coaxial cannula is passed through the right atrium with the tip of the cannula positioned in the main pulmonary artery. Thus the blood is actively removed from the right atrium and returned to the pulmonary artery. RESULTS: We successfully used this right heart support in 2 patients undergoing elective OPCAB. In both cases the system was used during the exposure of the proximal portion of the obtuse marginal branch. A mean pump flow of 3.2 l/min guaranteed normal cardiac output and hemodynamic stability during the exposure of the posterior target area. No complication occurred and the patients were discharged shortly after surgery. CONCLUSIONS: In our early experience the A-Med right heart support was safe and effective and allowed achievement of hemodynamic stability during exposure of the posterior areas of the left ventricle.

Norepinephrine can be useful for the treatment of right ventricular failure combined with acute pulmonary hypertension and systemic hypotension. A case report.

A 48-year-old woman who underwent emergency cardiac surgery for removal of a thrombus partially occluding the mitral valve, developed pulmonary hypertension right ventricular failure and systemic hypotension, in the immediate postoperative period, a clinical condition not well controlled by high doses of epinephrine and dobutamine. The addition of a continuous infusion of norepinephrine in incremental dosages, caused the rise in cardiac index accompanied before by the reduction in the pulmonary pressure and the stability in the systemic pressure, than by the further reduction in the pulmonary pressure and the increase in the systemic pressure. The conclusion is drawn that norepinephrine is useful in the treatment of right ventricular failure which follows a condition of acute pulmonary hypertension, because the improvement of cardiac performance established without adverse effects on the pulmonary pressures whose values on the contrary progressively declined.

Open heart surgery in patients with dialysis-dependent renal insufficiency.

OBJECTIVE: Chronic renal failure (CRF) is commonly considered a significant factor for increased morbidity and mortality after cardiac surgery. METHODS: To assess the risk in our population we retrospectively analyzed 28 patients (16 men and 12 women, mean age 58.1+/-10.8 years) with end-stage renal disease (ESRD) undergoing cardiac surgery between 1989 and 2001. Sixteen (57.2%) patients had isolated coronary artery bypass grafting (CABG), nine (32.1%) had isolated valve replacement, and three (10.7%) underwent combined CABG and valve replacement. Preoperatively, 20 (71.4%) patients were on hemodialysis and eight (28.6%) on peritoneal dialysis. Mean preoperative duration of dialysis was 38.7+/-24.9 months (range, 3 to 93 months). RESULTS: There were two perioperative deaths (30-day mortality, 7.1%). Actuarial survival at 1, 2, 5, and 12 years was 0.85+/-0.7, 0.73+/-0.10, 0.65+/-0.12, and 0.54+/-0.14, respectively. Among 22 survivors, mean NYHA class was 1.7+/-0.8 (p < 0.001 vs. preoperatively) and mean CCS class was 1.6+/-0.6 (p < 0.001 vs. preoperatively). CCS/NYHA functional class IV (p = 0.01), urgent/emergency operation (p < 0.001), LVEF < 35% (p < 0.001) were strongly related to early and late mortality. CONCLUSIONS: Open-heart operations can be performed with acceptable short- and long-term results in patients with CRF on dialysis. Adequate preoperative management with identification of high-risk patients and a more aggressive approach before the onset of symptoms of cardiac failure are advisable.

ARDS after double extrinsic exposure hypersensitivity pneumonitis.

Hypersensitivity pneumonitis or extrinsic allergic alveolitis is a lung disease due to T cell and macrophage activation with IgA, IgG or IgE immunocomplex tissue lesions following extrinsic exposure to organic or inorganic agents. We report a case of hypersensitivity pneumonitis (pigeon protein sensitized) with a second nosocomial exposure to Aspergillus fumigatus proteins from a contaminated oxygen water humidifier: the second extrinsic exposure induced significant acute respiratory failure with ARDS. A pre-existing COPD syndrome requiring prolonged oxygen therapy (7 days) involved lung disease with delayed clinical diagnosis and therapy. Microbiological and mycological analysis of oxygen water humidifiers should be considered, especially for hypersensitivity pneumonitis patients, when a new inexplicable clinical impairment occurs.

[Anesthesiologic problems in patients with Launois-Bensaude-Madelung disease. Clinical case]. / Problematiche anestesiologiche in pazienti affetti da malattia di Launois-Bensaude-Madelung. Caso clinico.

Authors report a Launoise-Bensaude-Madelung disease case, in a 64 year old man, admitted to a Plastic Surgical Department for obesity, dysphonia, dysphagia, dyspnea. Early symptoms appeared 20 years before Hospital admission. Lipomatous tissue occupied nape, mandible, neck and shoulders. Surgical exeresis of lipomatous tissue under general anesthesia needed for the patient. Neck movements and mouth opening were short (Mallampati Score = 4); a neck computed tomography showed a tracheal compression and right displacement. Tracheal intubation was considered difficult or impossible. Nose-tracheal intubation was performed using a pediatric fiberoptic instrument as guide for a small gauge tracheal tube. Tracheal stenosis required many attempts for correct nose-tracheal intubation. Fiberoptic instrument as guide for tracheal tube can be useful for patients with Launoise-Bensaude-Madelung disease, when tracheal intubation is considered difficult or impossible. Knowledge of fiberoptic tracheal intubation techniques is mandatory for anesthesiologists, allowing tracheal intubation in patients with anatomical variations of mouth or upper respiratory airways.

The effect of laparoscopic cholecystectomy on cardiovascular function and pulmonary gas exchange.

Hemodynamic changes, pulmonary CO2 elimination (VECO2) and gas exchange were evaluated during laparoscopic cholecystectomy. An algorithm to calculate inspired ventilation (VI) needed to maintain constant PaCO2 was also developed. In 12 ASA physical status I patients undergoing laparoscopic cholecystectomy, heart rate (HR), mean arterial pressure (MAP), cardiac index (CI), and systemic vascular resistance index (SVRI) were measured by the analysis of a radial artery pressure profile before, during, and after CO2 insufflation. Alveolar-arterial oxygen pressure gradient (P(A-a)O2), physiological and alveolar ventilatory dead space fractions (VDphys/VT; VDalv/VT), and PaCO2 were measured as well. VECO2 was assessed every minute in the patients maintained in the head-up position. HR did not significantly change during pneumoperitoneum, whereas MAP showed a transient increase (24.9%; P < 0.05) after CO2 insufflation. CI remained stable during pneumoperitoneum, but increased (25.0%; P < 0.05) after deflation. As a consequence, SVRI transiently increased after CO2 insufflation and decreased by 15.8% (P < 0.05) 5 min after deflation. P(A-a)O2 increased slightly (P < 0.05) with increased anesthesia time. VDphys/VT and VDalv/VT did not change after pneumoperitoneum onset, but VDalv/VT decreased after CO2 deflation (13.4%; P < 0.05). VECO2 increased (decreased) after a monoexponential time course during (after) CO2 insufflation in 8 of 12 patients. The mean time constants (t) of the monoexponential functions were 26.3 and 15.4 min during and after pneumoperitoneum. A monoexponential time course was shown also by PaCO2 during CO2 insufflation (tau = 27.8 min). Finally, the VI needed to maintain PaCO2 at a selected value could be calculated by the following algorithm: VI = [0.448.(1-e(-t/tau) + 2.52].(VA.PaCO2.713)-1, where VA corresponds to alveolar ventilation and t must be chosen according to the pneumoperitoneum phase. We conclude that CO2 insufflation in the abdominal cavity does not induce significant changes in cardiopulmonary function in ASA physical status I patients. The algorithm proposed seems to be a useful tool for the anesthesiologists to maintain constant PaCO2 during all surgical procedures.

The effects of intraperitoneal local anesthetic on analgesic requirements and endocrine response after laparoscopic cholecystectomy: a randomized double-blind controlled study.

This randomized double-blind placebo-controlled study was designed to evaluate the effects on postoperative pain of the local anesthetic, 0.5% bupivacaine with epinephrine, sprayed hepatodiaphragmatically under the surgeon's direct view during laparoscopic cholecystectomy. Metabolic endocrine responses to surgery (glucose and cortisol) and nonsteroidal anti-inflammatory drug requirements were investigated, as well as the presence of nausea, vomiting, and sweating. Local anesthetics or placebo solutions were given as follows. Immediately following the creation of a pneumoperitoneum, surgeons sprayed the first 20 mL of solution (S1), and an additional 20 mL of solution (S2) was sprayed at the end of the operation. Patients were classified into three groups (14 patients per group). Group A received 20 mL of saline during both S1 and S2, group B received 20 mL of saline during S1 and 20 mL of bupivacaine during S2, and group C received 20 mL of bupivacaine during both S1 and S2. The degree of postoperative pain was assessed using the visual analogue scale (VAS) and the verbal rating scale (VRS) on arrival in the recovery room and subsequently at time intervals of 4 h, 8 h, 12 h, and 24 h. The results of this study indicate a significant decrease of postoperative pain in patients treated with local anesthetic. VAS and VRS pain scores, as well as respiratory rate and analgesic requirements, were significantly lower in group C. The postoperative plasma cortisol level in group C was significantly lower than in groups A and B.

[Effects of age, body weight, and ventilatory pattern on the difference between arterial and end-tidal PCO2]. / Effetti di età, peso corporeo e pattern ventilatorio sulla differenza tra PCO2 arteriosa e fine espirazione.

OBJECTIVE: To evaluate the effects of physiological ventilatory patterns on P(a-ET)CO2 gradient and on the alveolar dead space production during controlled mechanical ventilation. DESIGN: Prospective and experimental comparison among three different ventilatory settings in three different groups of subjects. SETTING: General surgery's operating-theatre in university hospital. PATIENTS: Twenty-eight patients subdivided randomly in 3 groups differing for ventilatory setting. I group: constant tidal volume (VC = 8 ml.kg-1) and 3 different respiratory frequencies (f = 10, 12 and 14 breaths.min-1); II group: constant ventilation (112 ml.kg-1) but VC and f modified in three different ways; III group: inspiratory volume was set to give an end-tidal PCO2 (PETCO2) of about 35 mmHg. The cases were subdivided, on the basis of P(a-ET)CO2 distribution, in three groups: group with values larger than mean plus 1 standard deviation, group with values between +/- 1 standard deviation and group with values lower than mean minus 1 standard deviation. Moreover in two homogeneous groups for age. INTERVENTIONS: General surgery but not important because measures were performed before surgical manoeuvres. MEASUREMENTS AND MAIN RESULTS: Anthropometrical data (age and body weight), PaCO2, PETCO2, heart rate, invasive arterial pressure, ventilatory parameters and airway pressure were collected for every subject and ventilatory setting; arterial to end-tidal difference P(a-ET)CO2 and P(a-ET)CO2.PaCO2(-1) were calculated during data analysis. The P(a-ETFCO2 and P(a-ET)CO2.PaCO2(-1) values were not significantly different among the three different ventilatory patterns both in the first and in the second group. P(a-ET)CO2 values were significantly correlated with age, body weight and airway pressure. These parameters were correlated significantly also with P(a-ET)CO2.PaCO2(-1) values. CONCLUSIONS: Ventilatory setting, used in a normal physiological range, don't affect P(a-ET)CO2 difference during mechanical ventilation. Age, body weight and airway pressure of the patient must be considered to obtain a correct value of PaCO2 by the measure of PETCO2.

[ARDS in a severe case of primary pulmonary infection caused by Legionella pneumophila]. / ARDS in un grave caso di infezione polmonare primitiva da Legionella pneumophila.

The authors report a case of ARDS following pneumonia caused by Legionella pneumophila, in a thirty year old young man. Mechanical ventilation was maintained for twenty days. The gravity of ARDS and pneumonia, perhaps was caused because infective agent and the efficacious antibiotic were identified too late: twelve days after the comparison of symptoms. In fact, early laboratory diagnosis of Legionella pneumonia, is currently very difficult. A primitive extranocosomial pneumonia with rapid development to ARDS, in a good health young man, is an uncommon event. The exclusion of particular causes of ARDS, such as narcotic over-dose, AIDS, lung cancer, lymphatic carcinomatosis, and the clinical suspicion of Legionella pneumonia presence, can be useful: waiting for the right diagnosis from the laboratory, it will be possible to begin antibiotic therapy with Erythromycin (often used for slight respiratory infections), and to prevent the evolution of illness.