Efectividad de la utilización de xilocaína endotraqueal para extubación despierto / Effects of endotracheal administered Xilocaine on symptoms control during tracheal extubation

La aspiración del contenido gástrico dentro del árbol traqueobronquial es un evento poco común durante el acto anestésico, pero juega un papel importante en la morbilidad y mortalidad de los pacientes anestesiados, produciendo consecuencias graves, como neumonitis por aspiración (clínicamente aparente: 1.4 por 10.000 anestesias) y falla respiratoria. La mayoría de aspiraciones pulmonares se presentan en el momento de la extubación (51 por ciento), por inhibición de los reflejos laringeos debido a sedantes o a efectos residuales de la anestesia general. Los efectos de la administración endotraqueal de la Xilocaína en el control de los síntomas durante la extubación traqueal bajo anestesia general con el paciente despierto fueron evaluados. Un estudio prospectivo con 60 pacientes ASA I y ASA II bajo anestesia general fueron utilizados para determinar si la aplicación endotraqueal de 1.5 mg/kg de Xilocaína al 2 por ciento con la cánula de aspersión en el momento de la extubación puede disminuir la incidencia de síntomas postoperatorios como tos, pujo y laringoespasmo. Este estudio concluye que la incidencia de síntomas disminuyó significativamente (p<0.01) cuando la Xilocaina fue inyectada por vía endotraqueal en el momento de la extubación con la cánula de aspersión previniendo los síntomas postoperatorios durante el despertar de la anestesia en el paciente que despierta intubado

Síndrome de reperfusión: fisiopatología, prevención y manejo / Hypoperfusion syndrome: physiopathology, prevention and management

Los fenómenos isquémicos o de hipoperfusion ocasionan una disminución del aporte de oxigeno hasta alcanzar un nivel critico donde el consumo se hace dependiente de dicho aporte creándose a nivel celular un estado conocido como Deuda de Oxigeno, anunciando el inicio del metabolismo anaerobico. Dependiendo del tiempo, el fenomeno de isquemia-anoxia va causando daño celular progresivo hasta la muerte, pero si se establece la reperfusion tisular antes del daño letal, la celula puede reaccionar recuperándose completamente, o por el contrario. incrementando la lesion que tenia previa a la reperfusion, lo que se conoce como la injuria post-reperfusión (I-R), la cual puede ser minimizada, si se somete al tejido a breves periodos de isquemia reversible previos al periodo de isquemia definitiva, estableciendo de esta forma lo que comunmente se denomina preacondicionamiento isquemico

Carbon dioxide supersaturation in the surface waters of lakes.

Data on the partial pressure of carbon dioxide (CO(2)) in the surface waters from a large number of lakes (1835) with a worldwide distribution show that only a small proportion of the 4665 samples analyzed (less than 10 percent) were within +/-20 percent of equilibrium with the atmosphere and that most samples (87 percent) were supersaturated. The mean partial pressure of CO(2) averaged 1036 microatmospheres, about three times the value in the overlying atmosphere, indicating that lakes are sources rather than sinks of atmospheric CO(2). On a global scale, the potential efflux of CO(2) from lakes (about 0.14 x 10(15) grams of carbon per year) is about half as large as riverine transport of organic plus inorganic carbon to the ocean. Lakes are a small but potentially important conduit for carbon from terrestrial sources to the atmospheric sink.

Initial experience with percutaneous placement of the PAS port implantable venous access device.

The authors evaluated a new venous access port designed for peripheral venous insertion in the interventional radiology suite. Forty ports were placed in 40 patients in either the brachial, cephalic, or basilic vein under fluoroscopic guidance. These ports have been used for blood transfusion, blood sampling, parenteral nutrition, chemotherapy, and antibiotic therapy. The ports have been in use for 4,241 consecutive patients days. There have been no clinically apparent venous thrombotic complications and only one device-related infection. The cost and risk of complication are less than those for a surgically placed chest wall port, and the cosmetic result is excellent. This port has had excellent patient, nursing, and clinical acceptance.

Subtyping lymphocytes in peripheral blood by direct immunoalkaline phosphatase labeling and light scatter/absorption flow cytometric analysis.

Evaluation of blood cells to determine immunologic status is becoming an important clinical application of flow cytometric analysis. For a wider use of immunophenotyping technology in clinical laboratories, the authors developed a rapid method to detect monoclonal antibody-labeled cells using forward light scatter/absorption clinical flow cytometers such as the Technicon H*1 and Technicon H*2 differential complete blood count analyzers. Calf-intestinal alkaline phosphatase was conjugated to mouse monoclonal antibodies (anti-CD2, CD3, CD4, CD8, CD19) for direct immunoenzymatic labeling. The combination of 5-bromo-4-chloro-3-indolyl phosphate and nitroblue-tetrazolium salt in diethanolamine buffer at pH 9.6 was selected as buffer/substrate to yield stable, insoluble, and very intense purplish-blue precipitates on the surface of the cells labeled with monoclonal antibody-alkaline phosphatase conjugates. Endogenous alkaline phosphatase in granulocytes was inhibited with levamisole. Early mild fixation of the white cells permitted incubation at 38 +/- 1 degrees C, which accelerated each step of the reaction without disrupting the cells throughout the procedure. The method is competitive with the direct immunofluorescence whole-blood method used on fluorescence flow cytometers in speed, sensitivity, and accuracy, as demonstrated with alkaline phosphatase-conjugated anti-CD2, CD3, CD4, CD8, CD19 monoclonal antibodies.

Resident interpretation of emergency computed tomographic scans.

Our busy, urban emergency room is staffed by radiology residents after working hours. To determine the accuracy of our residents' interpretations of emergency cranial computed tomographic (CT) scans, the authors reviewed the preliminary reports of our residents for a two-month period. A total of 289 cranial CT scans were retrospectively reviewed and the resident interpretation judged acceptable, minor error, moderate error, or major error. Six of 289 neurologic examinations (2%) had moderate (4) or major (2) errors. The mistakes all involved misinterpretation of cerebral hemorrhage. The 98% accuracy in interpretation of cranial CT is higher than the accuracy reported with emergency plain film (PF) interpretation.

Objective assessment of swallowing function in head and neck cancer patients.

Swallowing function was evaluated with scintigraphy in 37 patients with head and neck cancer. The patients were examined before and during the course of either surgery, chemotherapy, and/or radiotherapy. A total of 118 scintigraphic studies were performed. Scintigraphic results of bolus flow and aspiration were correlated with clinical findings. Both scintigraphic and clinical studies indicated a worsened swallowing function in 12 patients. These same studies indicated improvement of swallowing in another 13 patients. In 11 patients, both studies revealed either no apparent change or mixed changes in swallowing function after the course of therapy. In only 1 patient was there disagreement between the scintigraphic and clinical assessment of swallowing function. It is our opinion that scintigraphy is a useful method for objective assessment of swallowing function during and after the course of treatment of head and neck cancer patients.

Arctic lakes and streams as gas conduits to the atmosphere: implications for tundra carbon budgets.

Arctic tundra has large amounts of stored carbon and is thought to be a sink for atmospheric carbon dioxide (CO(2)) (0.1 to 0.3 petagram of carbon per year) (1 petagram = 10(15) grams). But this estimate of carbon balance is only for terrestrial ecosystems. Measurements of the partial pressure of CO(2) in 29 aquatic ecosystems across arctic Alaska showed that in most cases (27 of 29) CO(2) was released to the atmosphere. This CO(2) probably originates in terrestrial environments; erosion of particulate carbon plus ground-water transport of dissolved carbon from tundra contribute to the CO(2) flux from surface waters to the atmosphere. If this mechanism is typical of that of other tundra areas, then current estimates of the arctic terrestrial sink for atmospheric CO(2) may be 20 percent too high.

Surface coil FLASH magnetic resonance imaging of the fasting and secretin-stimulated pancreas.

The purpose of this study is to investigate the response of the pancreas to secretin stimulation using magnetic resonance imaging (MRI). Using the Siemens 1.0 T Magnetom and a Helmholtz surface coil, single breath FLASH-MRI of the normal fasting pancreas was performed in the prone position, both before and after a 20-minute period after intravenous (IV) bolus injection of secretin (2 cu/kg). T2*-weighted fast low-angle shot sequences (TR = 150 mseconds; TE = 30 mseconds; flip angle = 10 degrees; matrix = 256 X 256; acquisitions = 2) demonstrated an immediate response manifested by a significant distension of the duodenum with fluid secreted by the pancreas, as well as a gradual decline of the pancreas/muscle signal intensity (SI) ratio over time. Twenty minutes after secretin administration, the mean percent decrease of the pancreas/muscle SI ratio in six volunteers was 11.6 +/- 6.4 (1-STD). This is statistically significant (P less than .003) given a mean percent increase of the pancreas/muscle SI ratio of 1.6 +/- 4.8 (1-STD) in five volunteers 20 minutes after bolus injection of saline (control). Although significant duodenal distension is easily demonstrated after secretin administration, the decrease of the relative pancreatic SI over time is visually subtle. Further work is needed to enhance imaging of the physiologic response of the pancreas using even more rapid imaging techniques.

Scintigraphic findings in patients with shoulder pain caused by interleukin-2.

Interleukin-2 is receiving widespread interest as an immunotherapeutic agent in the treatment of certain cancers. Severe arthralgias recently have been reported as a significant side effect, and the cause of pain is unknown. Because interleukin-2 is an immune modulator, we reviewed the 99mTc-methylene diphosphonate scintigrams in nine patients who had developed shoulder arthralgias while receiving interleukin-2 for metastatic melanoma. In eight of the patients, the scintigrams showed diffuse increased uptake of radionuclide in the shoulders. Four patients had radiographs of their shoulders, all of which were normal. Bone scintigraphy in patients receiving interleukin-2 as immunotherapy for metastatic melanoma shows increased radionuclide activity in the shoulders. This process may relate to the role of interleukin-2 as a mediator in the inflammatory response.

Nuclear scintigraphy in the evaluation of renal colic.

Forty patients with acute onset renal colic were studied using technetium-99m DTPA renal scintigraphy. Thirty-two were found to have varying degrees of obstruction. In the obstructed group the level was determined by the scan alone in 24 of 32 cases (75%). When the analysis included an abdominal radiograph, the level of obstruction was ascertained in 29 of 32 cases (91%). A delayed nephrogram, as evidenced by an "empty renal pelvis sign" at 5 minutes, was observed in all but one of the cases of obstruction (97%). Delayed clearance of activity from the pyelocalyceal system or ureter was also seen in 97%. In all cases of obstruction either one or both of these signs were observed. However, delayed clearance was found to be a nonspecific finding and was noted in 25% of nonobstructed cases. The finding of the "empty renal pelvis sign" at 5 minutes was found to be specific and was not seen in the nonobstructed group. The authors conclude that radionuclide renal scanning is an effective method for evaluating selected patients with suspected renal colic.

Prevention of allogeneic bone marrow graft rejection by H-2 transgene in donor mice.

Rejection of bone marrow grafts in irradiated mice is mediated by natural killer (NK) cells and is controlled by genes linked to the major histocompatibility complex (MHC). It has, however, not been possible to identify the genes or their products. An MHC class I (Dd) transgene introduced in C57BL donors prevented the rejection of their bone marrow by NK cells in irradiated allogeneic and F1 hybrid mice expressing the Dd gene. Conversely, H-2Dd transgenic C57BL recipients acquired the ability to reject bone marrow from C57BL donors but not from H-2Dd transgenic C57BL donors. These results provide formal evidence that NK cells are part of a system capable of rejecting cells because they lack normal genes of the host type, in contrast to T cells, which recognize cells that contain abnormal or novel sequences of non-host type.

The groin hit: complications of intravenous drug abuse.

We are seeing an increased number of complications in intravenous drug abusers who resort to injecting the groin for vascular access (the "groin hit"). Vascular complications include venous thrombosis, arteriovenous fistula, mycotic aneurysm, ruptured pseudoaneurysm, and dissecting hematoma. Soft tissue complications include cellulitis and abscess. The latter may dissect into the extraperitoneal space. Skeletal complications include osteomyelitis and septic arthritis. This paper illustrates the radiographic spectrum of these complications. An algorithm will illustrate the radiographic evaluation of a groin mass in a drug addict.

Molecular analysis of H-2-deficient lymphoma lines. Distinct defects in biosynthesis and association of MHC class I heavy chains and beta 2-microglobulin observed in cells with increased sensitivity to NK cell lysis.

It has previously been reported that MHC class I-deficient RBL-5 and YAC-1 lymphoma sublines show an enhanced NK sensitivity in vitro. In the present study such lymphoma variants were found to have different defects in H-2 biosynthesis such as 1) reduced beta 2-microglobulin and H-2 H chain transcription, 2) block in beta 2-microglobulin translation, and 3) impaired association between beta 2-microglobulin and H-2 H chains. For lines with the latter two defects, the results suggested that a major part of the H chains were arrested before the middle Golgi complex as indicated by their failure to undergo carbohydrate side chain trimming. The data suggest that NK sensitivity can be directly influenced by the membrane expression of MHC class I gene products of tumor targets because three independent molecular defects, all interfering with the cell surface H-2 expression, gave rise to NK-sensitive phenotypes. These variant lines will also be useful tools for studies of H-2 glycoprotein assembly and transport and for Ag presentation to CTL.

Cocaine abuse: neurovascular complications.

In a review of the records of 3,712 drug abusers, 13 patients were identified with neurologic deficits attributable to the use of cocaine. Ischemic manifestations were the most frequent, occurring in seven (54%) patients, with a mean age of 34.2 years. Three (23%) patients had subarachnoid hemorrhage, and three (23%) had intracerebral hemorrhage. Three patients from other institutions were included in the analysis, for a total of 16 patients, (eight with cerebral ischemia, four with subarachnoid hemorrhage, and four with intracerebral hemorrhage). Of the six patients with head computed tomographic findings of cerebral infarction, five had subcortical infarcts. Two of the four patients who presented with a subarachnoid hemorrhage had a congenital intracranial aneurysm. One of the four patients with an intracerebral hemorrhage had an underlying arteriovenous malformation. The mechanism through which these complications occur is not completely understood. Factors that may play a role include the acute hypertensive response that occurs with cocaine use as well as disordered neurovascular control.

Pyogenic sacroiliitis in i.v. drug abusers.

We evaluated the sensitivity of imaging studies in six IV drug abusers who had back pain from pyogenic sacroiliitis. Initial radiographs of the sacroiliac joints showed bone destruction in two. A third had slight joint narrowing and sclerosis resembling degenerative disease. Radiographs were considered normal in three. Two of the patients with initially normal radiographs subsequently showed loss of cortices on follow-up studies within 2 weeks. All of the patients had increased activity on scintigrams (five were obtained with technetium-99m methylene diphosphonate; one was with gallium). The findings suggest that scintigraphy is useful in the detection of pyogenic sacroiliitis in IV drug abusers when plain films are normal.

Seasonal mixing and catastrophic degassing in tropical lakes, cameroon, west Africa.

Lethal gas releases from Lakes Nyos and Monoun in Cameroon seem to be more lacustrine than volcanic in origin. Both of these events occurred in August and were only 2 years apart. Data show that the period of deepest mixing and lake turnover also occurs during late summer in this region of tropical Africa. In addition, recent trends of decreases in both air temperatures and effective insolation relative to long-term means suggest that weakening of stratification, coupled with a predictable seasonal interval of reduced stability in August, may be responsible for the timing of these events.