Sadek Beloucif

Clinical experience with the mini-extracorporeal circulation system: an evolution or a revolution?

PURPOSE We studied a cohort of 150 patients operated on with a new cardiopulmonary bypass (CPB) system. This is the mini-extracorporeal circulation (MECC) system. DESCRIPTION The MECC is a fully heparin coated closed-loop CPB system that includes a centrifugal pump and has a priming volume of 450 mL. Between March 2001 and September 2002, 150 consecutive patients were operated on using the mini-CPB (MECC) method. This includes 105 coronary artery bypass graft and 45 aortic valve replacement patients. The median age was 66.7 +/- 10.7 years with a gender ratio of 3.27 males to 1 female. EVALUATION The 30-day operative mortality was 1.3%. The hemoglobin concentration was stable and perioperative transfusion was needed in only 6% of all patients. The renal and neuropsychiatric complications were less than 1%. CONCLUSIONS In our experience, the MECC system is a reliable new concept for CPB with good clinical results.

Nitric oxide in sepsis.

The synthesis of nitric oxide (NO) and its targets are reviewed physiologically during sepsis and wound healing, a self-limiting process in which mechanisms are still identified incompletely. NO also plays an active and direct role during infection, aimed at protecting the host and destroying the microbe. During septic shock, an overproduction of NO has been described experimentally and clinically that might be responsible for the systemic vasodilatation with hyporesponsiveness to exogenous vasoconstrictive agents. The different manipulations of NO pathway during sepsis are described (transcription and post-transcription of iNOS, enzymatic function, substrate availability, NO concentration, and NO effector molecules), although their clinical benefit remains controversial.

No Involvement of Antidiuretic Hormone in Acute Antidiuresis During PEEP Ventilation in Humans

: Decreased urinary output (Vu ml/min) after institution of PEEP is attributed to a variety of mechanisms including decreased cardiac output and renal blood flow (RBF), activation of neurohormonal reflexes, increased catecholamines, plasma renin activity (PRA), and antidiuretic hormone (ADH) release. To evaluate these factors, seven normovolemic patients (36 yr +/- 13 SD), free of preexisting lung, cardiac, or renal disease, requiring continuous mandatory ventilation for neurologic reasons were studied. The authors measured or calculated: total blood volume (TBV) (51Cr); right atrial, pulmonary arterial, pulmonary wedge, and systemic pressures, cardiac index (CI); renal plasma flow (RPF) (iodohippurate sodium 131I [131I PAH] clearance); glomerular filtration rate (GFR) (creatinine clearance), free water clearance (CH2O), osmolal clearance (Cosm), fractional excretion of sodium (FENa+) and potassium (FEK+); and plasma renin activity (PRA) (ng X ml-1 X h-1), plasma ADH (pg/ml; radioimmunoassay), epinephrine (E in pg/ml), and norepinephrine (NE in pg/ml) (double-isotope radioenzymatic assay). Two conditions were studied after 90-min steady state: 1) zero PEEP (ZEEP); and 2) 15 cmH2O PEEP. PEEP caused a significant decrease in CI (-21%; P less than 0.01) and RPF (-19%; P less than 0.05) without significant decrease in GFR. A significant decrease in Vu (-55%; P less than 0.05), FENa+ (-39%; P less than 0.05) and Cosm (-36%; P less than 0.25) occurred without modification in CH2O. Plasma ADH remained in the normal range and did not increase when PEEP was applied.(ABSTRACT TRUNCATED AT 250 WORDS)

Human Transplantation of a Biologic Airway Substitute in Conservative Lung Cancer Surgery

BACKGROUND Pneumonectomies for lung cancer are associated with a high postoperative mortality, especially when right-sided, after neoadjuvant radiochemotherapy, and in patients over 70 years of age. Preliminary studies in our laboratory have shown that aortic grafts could be valuable airway substitutes. We report the first human bronchial transplantation of a cryopreserved aortic allograft used as a biologic airway substitute to prevent a pneumonectomy for lung cancer. METHODS The procedure was performed in a high-risk 78-year old patient with an extensive right bronchopulmonary malignant tumor pretreated with chemotherapy. After a complete resection of the lung cancer using an upper bilobectomy with lymph node removal, mobilization procedures did not allow for a primary end-to-end bronchial anastomosis. A stent-supported cryopreserved aortic allograft from a certified tissue bank was interposed to restore the bronchial continuity with sparing of the lower lobe. RESULTS The postoperative course was eventful for a supraventricular arrhythmia leading to mild pulmonary edema that resolved using standard medical therapy, and a right lower lobe atelectasis with bacterial colonization that required fiberoptic bronchoscopies in addition to antibiotic treatment. A 1-year postoperative evaluation found a well-functioning reimplanted lower lobe with no complications related to the cryopreserved aortic allograft or the stent. The patient recovered to his baseline activity with a satisfying health-related quality of life. CONCLUSIONS We demonstrate the feasibility of this surgical innovation to prevent the high-risk procedure of pneumonectomy in a single case. If confirmed in larger series of selected patients, it could bring new perspectives in conservative lung cancer surgery.

Evaluation of pulsed doppler common carotid blood flow as a noninvasive method for brain death diagnosis: a prospective study

Among the main causes for the relatively small number of organ donors, the delay in the diagnosis of brain death plays a major role. This prospective study was designed to evaluate whether pulsed Doppler mean and phasic common carotid blood flow (CCBF) combined with arterial and jugular venous blood gases could rapidly and specifically establish a diagnosis of brain death. CCBF was measured by an 8 MHz pulsed Doppler flowmeter, allowing measurement of the vessel diameter via a double transducer probe, which fixed the ultrasonic incidence angle. From an initial series of patients (n = 28) with an established diagnosis [brain death n = 14; severe coma with a Glasgow Coma Scale (GCS) less than 7, n = 14], the results of the logistic regression analysis process yielded the most discriminating parameters for brain death diagnosis: end-diastolic velocity (Ved - 1.4 vs. 12.7 cm/s; t = 7.67, P = 0.001) and blood flow (Qed - 13.6 vs. 121.4 ml/min). These parameters were then tested in a blind fashion on a second series of 28 comatose patients (GCS = 7). They resulted in correct diagnosis (brain death n = 14 or severe coma n = 14) for all patients. Brain death diagnosis was confirmed by clinical signs, EEG, and/or angiography. From the analysis of the overall population (n = 56), a value of Qed of less than 31.4 ml/mn indictes brain death. The authors conclude, that pulsed Doppler measurements of CCBF represent an early, low cost and noninvasive technique, the results of which may prompt legally accepted procedures, which in turn would reduce the delay required before brain death is diagnosed. Moreover, this technique could help in deciding on discontinuation of active therapy in severely injured patients.

Case Scenario: Bronchospasm during Anesthetic Induction

This article has been selected for the ANESTHESIOLOGY CME Program. Learning objectives and disclosure and ordering information can be found in the CME section at the front of this issue.

Face Mask Ventilation in Edentulous Patients: A Comparison of Mandibular Groove and Lower Lip Placement

Background:In edentulous patients, it may be difficult to perform face mask ventilation because of inadequate seal with air leaks. Our aim was to ascertain whether the “lower lip” face mask placement, as a new face mask ventilation method, is more effective at reducing air leaks than the standard face mask placement. Methods:Forty-nine edentulous patients with inadequate seal and air leak during two-hand positive-pressure ventilation using the ventilator circle system were prospectively evaluated. In the presence of air leaks, defined as a difference of at least 33% between inspired and expired tidal volumes, the mask was placed in a lower lip position by repositioning the caudal end of the mask above the lower lip while maintaining the head in extension. The results are expressed as mean ± SD or median (25th–75th percentiles). Results:Patient characteristics included age (71 ± 11 yr) and body mass index (24 ± 4 kg/m2). By using the standard method, the median inspired and expired tidal volumes were 450 ml (400–500 ml) and 0 ml (0–50 ml), respectively, and the median air leak was 400 ml (365–485 ml). After placing the mask in the lower lip position, the median expired tidal volume increased to 400 ml (380–490), and the median air leak decreased to 10 ml (0–20 ml) (P < 0.001 vs. standard method). The lower lip face mask placement with two hands reduced the air leak by 95% (80–100%). Conclusions:In edentulous patients with inadequate face mask ventilation, the lower lip face mask placement with two hands markedly reduced the air leak and improved ventilation.

ALVEOLAR NEUTROPHIL OXIDATIVE BURST AND β2 INTEGRIN: EXPRESSION IN EXPERIMENTAL ACUTE PULMONARY INFLAMMATION ARE NOT MODIFIED BY INHALED NITRIC OXIDE

It was recently proposed that nitric oxide (NO) inhalation interferes with polymorphonuclear neutrophil (PMN) activation status during acute pulmonary inflammation, although variable results have been observed considering timing of NO administration, species, and model differences. After intratracheal administration of lipopolysaccharide (LPS) in rats, we characterized pulmonary inflammatory reaction (lung wet, dry, and wet to dry weights) and, using flow cytometry, the activation status (H2O2 production and β2 integrin CD11b/CD18 expression) of PMN obtained from blood and from bronchoalveolar lavage (BAL). Eight hours after LPS injection, rats received for an additional 10 h, at a same Fio2 (85%), either 15 parts per million NO or the same gas flow of nitrogen. We found that 18 h after LPS, lung wet, dry, and wet-to-dry weights, H2O2 production, and CD11b/CD18 expression were increased. PMN obtained from BAL were highly activated as evidenced by an already maximal expression of the β2 integrin CD11b/CD18, whereas the high H2O2 production at basal state could be further enhanced after ex vivo stimulation. Blood PMN were not different from control cells at basal state; however, their increased capacity to be stimulated ex vivo suggested an in vivo priming effect of intratracheal LPS. In conclusion, inhaled NO, given with a high Fio2, in the presence of this established endotoxinic lung injury did not reverse the markers of PMN activation studied nor lung edema formation in this rat model.

Inhaled nitric oxide, almitrine infusion, or their coadministration as a treatment of severe hypoxemic focal lung lesions.

Background The partition of pulmonary blood flow between normal and shunting zones is an important determinant of oxygen tension in arterial blood (PaO(2)). The authors hypothesized that the combination of inhaled nitric oxide (iNO) and almitrine infusion might have additional effects related to their pharmacologic properties to improve PaO(2). Such a combination was tested in patients with hypoxia caused by focal lung lesions, distinct from the acute respiratory distress syndrome. Methods Fifteen patients with hypoxic focal lung lesions despite optimal therapy were included and successively treated with (1) 5 ppm iNO, (2) low‐dose almitrine infusion (5.5 +/− 1.7 [micro sign]g [middle dot] kg (‐1) [middle dot] min‐1) during iNO, and (3) almitrine infusion alone (with NO turned off). Then iNO was reintroduced and we studied the effect of the coadministration in reducing the fractional concentration of oxygen in inspired gas (FIO(2)) and positive end‐expiratory pressure (PEEP) levels. Changes in blood gases and pulmonary and systemic hemodynamics were measured. Results Systemic hemodynamic variables remained stable in all protocol conditions. Use of iNO improved arterial oxygenation and decreased intrapulmonary shunt. Almitrine similarly improved PaO(2) but increased pulmonary artery pressure and right atrial pressure. Coadministration of iNO and almitrine improved PaO(2) compared with each drug alone and with control. All patients responded (that is, they had at least a +30% increase in PaO(2)) to this coadministration. When the drug combination was continued, FIO(2) and PEEP could be reduced over 8 h. The hospital mortality rate was 33% and unrelated to hypoxia. Conclusions In hypoxemic focal lung lesions, iNO or low‐dose almitrine markedly improved PaO(2) to a similar extent. Furthermore, the coadministration amplified the PaO(2) increase at a level that allowed reductions in FIO(2) and PEEP levels.

Determinants of systolic and diastolic flow in coronary bypass grafts with inotropic stimulation

Using implanted pulsed Doppler microprobes sutured on saphenous bypass grafts in ten patients we studied, 6 h after cardiac surgery, the effects of 5 and 10 micrograms.kg-1.min-1 of dobutamine on mean (Qm), systolic (Qs), and diastolic (Qd) coronary bypass graft flows, as well as on coronary systolic (integral of Qs) and diastolic (integral of Qd) blood volumes entering the myocardium per cardiac beat. Qm increased during the inotropic stimulation from 61.8 +/- 19.2 to 81.1 +/- 21.8 ml.min-1 (P less than 0.001) and resulted from an unchanged Qs and from a large increase in Qd (P less than 0.01). Qd increased more than did diastolic arterial pressure and was related to rate pressure product taken as an index of myocardial oxygen consumption (r = 0.76, P less than 0.001). Despite the dobutamine-induced increase in heart rate (P less than 0.01), integral of Qs, and integral of Qd, the systolic and diastolic inflow volumes per cardiac beat were unchanged. We conclude that increased myocardial blood supply through the saphenous vein bypass graft during inotropic stimulation by dobutamine resulted from different systolic and diastolic events. The oxygenated blood volume entering the coronary vascular bed per beat was unchanged despite tachycardia.