Edema pulmonar por presión negativa con máscara laríngea clásica. Presentación de un caso pediátrico / Pulmonary edema due to negative pressure with classical laryngeal mask. Presentation of a pediatric case

RESUMEN El edema pulmonar por presión negativa es una complicación rara y dramática en la anestesia general. Habitualmente ocurre como consecuencia de un laringoespasmo u otra causa de obstrucción de la vía aérea. Se presentó un caso con el objetivo de mostrar los elementos usados para el diagnóstico y tratamiento del edema pulmonar por presión negativa. Paciente de 7 años de edad, femenina, ASA I, operada de metatarso varo funcional con anestesia general balanceada y máscara laríngea clásica # 3. Desarrolló dicho evento adverso durante la recuperación anestésica. El diagnóstico se basó en la disociación toraco abdominal al restablecer la ventilación espontanea, crepitantes en ambos hemitórax, cianosis central, hipoxemia y la presencia de infiltrado difuso bilateral alveolar. Se intubó la tráquea, se controló la ventilación con presión positiva al final de la espiración y se administró furosemida. La paciente fue trasladada a la Unidad de Cuidados Intensivos donde evolucionó satisfactoriamente. Este es un síndrome cuya verdadera incidencia se desconoce debido a la escasa familiarización con el mismo. La evolución de los pacientes es favorable siempre que se establezca el diagnóstico y el tratamiento oportuno (AU).

ABSTRACT Pulmonary edema due to negative pressure is a rare and dramatic complication in general anesthetic. It usually occurs as a consequence of a laryngeal spasm or another cause of respiratory tract obstruction.A case was presented with the aim of showing the elements used for the diagnosis and treatment of the pulmonary edema due to negative pressure. An ASA I, 7-year-old female patient, was operated on a functional metatarsus varus with balanced general anesthetic and classical laryngeal mask number 3. She developed this adverse event during the anesthetic recovery. The diagnosis was based on the thoracoabdominal dissociation when recovering spontaneous ventilation, crepitation in hemithoraxes, central cyanosis, hypoxemia, and alveolar bilateral diffused infiltrate. The trachea was intubated, ventilation was controlled with positive pressure at the end of the expiration and furosemide was administered. The patient was transferred to the Intensive Care Unit where she evolved satisfactorily. This is a syndrome whose true incidence is unknown as a result of the lack of familiarization with it. Patients' evolution is favorable whenever the right diagnosis and treatment are timely established (AU).

Usefulness of radiological signs of pulmonary congestion in predicting failed spontaneous breathing trials / Utilidade de sinais radiológicos de congestão pulmonar para predizer o fracasso do teste de respiração espontânea

ABSTRACT Objective: Inspiratory fall in intrathoracic pressure during a spontaneous breathing trial (SBT) may precipitate cardiac dysfunction and acute pulmonary edema. We aimed to determine the relationship between radiological signs of pulmonary congestion prior to an SBT and weaning outcomes. Methods: This was a post hoc analysis of a prospective cohort study involving patients in an adult medical-surgical ICU. All enrolled individuals met the eligibility criteria for liberation from mechanical ventilation. Tracheostomized subjects were excluded. The primary endpoint was SBT failure, defined as the inability to tolerate a T-piece trial for 30-120 min. An attending radiologist applied a radiological score on interpretation of digital chest X-rays performed before the SBT. Results: A total of 170 T-piece trials were carried out; SBT failure occurred in 28 trials (16.4%), and 133 subjects (78.3%) were extubated at first attempt. Radiological scores were similar between SBT-failure and SBT-success groups (median [interquartile range] = 3 [2-4] points vs. 3 [2-4] points; p = 0.15), which, according to the score criteria, represented interstitial lung congestion. The analysis of ROC curves demonstrated poor accuracy (area under the curve = 0.58) of chest x-rays findings of congestion prior to the SBT for discriminating between SBT failure and SBT success. No correlation was found between fluid balance in the 48 h preceding the SBT and radiological score results (ρ = −0.13). Conclusions: Radiological findings of pulmonary congestion should not delay SBT indication, given that they did not predict weaning failure in the medical-surgical critically ill population. (ClinicalTrials.gov identifier: NCT02022839 [http://www.clinicaltrials.gov/])

RESUMO Objetivo: A queda inspiratória da pressão intratorácica durante o teste de respiração espontânea (TRE) pode provocar disfunção cardíaca e edema pulmonar agudo. Nosso objetivo foi determinar a relação entre sinais radiológicos de congestão pulmonar antes do TRE e desfechos do desmame. Métodos: Análise post hoc de um estudo prospectivo de coorte envolvendo pacientes em uma UTI medicocirúrgica de adultos. Todos os indivíduos incluídos preencheram os critérios de elegibilidade para liberação da ventilação mecânica. Pacientes traqueostomizados foram excluídos. O desfecho primário foi o fracasso do TRE, cuja definição foi a incapacidade de tolerar o teste de tubo T durante 30-120 min. Um radiologista assistente usou um escore radiológico na interpretação de radiografias de tórax digitais realizadas antes do TRE. Resultados: Foram realizados 170 testes de tubo T; o TRE fracassou em 28 (16,4%), e 133 indivíduos (78,3%) foram extubados na primeira tentativa. Os escores radiológicos foram semelhantes nos grupos fracasso e sucesso do TRE [mediana (intervalo interquartil) = 3 (2-4) pontos vs. 3 (2-4) pontos; p = 0,15] e caracterizaram, segundo os critérios do escore, congestão pulmonar intersticial. A análise das curvas ROC revelou que os achados de congestão na radiografia de tórax antes do TRE apresentavam baixa precisão (área sob a curva = 0,58) para discriminar entre fracasso e sucesso do TRE. Não houve correlação entre o balanço hídrico nas 48 h anteriores ao TRE e os resultados do escore radiológico (ρ = −0,13). Conclusões: Achados radiológicos de congestão pulmonar não deveriam atrasar o TRE, já que não previram o fracasso do desmame na população médico-cirúrgica em estado crítico. (ClinicalTrials.gov identifier: NCT02022839 [http://www.clinicaltrials.gov/])

Crise hipertensiva / Hypertensive crisis

Crise hipertensiva é uma situação clínica comum, caracterizada por elevação sintomática da pressão arterial. Apresenta alta taxa de morbidade e mortalidade e é classificada como emergência e urgência hipertensiva. O quadro clínico de emergência hipertensiva difere do quadro de urgência por apresentar risco de morte iminente decorrente de lesão em órgãos-alvo instalada ou em evolução, em particular no coração, cérebro, rins e artérias. Essa condição requer uma abordagem clínica criteriosa, que permita o diagnóstico rápido e correto do órgão-alvo envolvido.

Hypertensive crisis is a common clinical situation characterized by symptomatic rise of the blood pressure, it presents high rate of morbidity and mortality, and it is classified in hypertensive emergency and urgency. The clinical picture of hypertensive emergency differs from that of hypertensive urgency by presenting an imminent death risk due to established or developing damage in target-organs, especially heart, brain, kidneys and arteries. This condition requires a sensible clinical approach that allows a correct and fast diagnosis of the compromised target-organ.

Effect of methylprednisolone on perivascular pulmonary edema, inflammatory infiltrate, VEGF and TGF-beta immunoexpression in the remaining lungs of rats after left pneumonectomy

Pneumonectomy is associated with high rates of morbimortality, with postpneumonectomy pulmonary edema being one of the leading causes. An intrinsic inflammatory process following the operation has been considered in its physiopathology. The use of corticosteroids is related to prevention of this edema, but no experimental data are available to support this hypothesis. We evaluated the effect of methylprednisolone on the remaining lungs of rats submitted to left pneumonectomy concerning edema and inflammatory markers. Forty male Wistar rats weighing 300 g underwent left pneumonectomy and were randomized to receive corticosteroids or not. Methylprednisolone at a dose of 10 mg/kg was given before the surgery. After recovery, the animals were sacrificed at 48 and 72 h, when the pO2/FiO2 ratio was determined. Right lung perivascular edema was measured by the index between perivascular and vascular area and neutrophil density by manual count. Tissue expression of vascular endothelial growth factor (VEGF) and transforming growth factor-beta (TGF-β) were evaluated by immunohistochemistry light microscopy. There was perivascular edema formation after 72 h in both groups (P = 0.0031). No difference was observed between operated animals that received corticosteroids and those that did not concerning the pO2/FiO2 ratio, neutrophil density or TGF-β expression. The tissue expression of VEGF was elevated in the animals that received methylprednisolone both 48 and 72 h after surgery (P = 0.0243). Methylprednisolone was unable to enhance gas exchange and avoid an inflammatory infiltrate and TGF-β expression also showed that the inflammatory process was not correlated with pulmonary edema formation. However, the overexpression of VEGF in this group showed that methylprednisolone is related to this elevation.

Involvement of nitric oxide pathways in neurogenic pulmonary edema induced by vagotomy

OBJECTIVE: The objective of this study was to evaluate the involvement of peripheral nitric oxide (NO) in vagotomy-induced pulmonary edema by verifying whether the nitric oxide synthases (NOS), constitutive (cNOS) and inducible (iNOS), participate in this mechanism. INTRODUCTION: It has been proposed that vagotomy induces neurogenic pulmonary edema or intensifies the edema of other etiologies. METHODS: Control and vagotomized rats were pretreated with 0.3 mg/kg, 3.0 mg/kg or 39.0 mg/kg of L-NAME, or with 5.0 mg/kg, 10.0 mg/kg or 20.0 mg/kg of aminoguanidine. All animals were observed for 120 minutes. After the animals' death, the trachea was catheterized in order to observe tracheal fluid and to classify the severity of pulmonary edema. The lungs were removed and weighed to evaluate pulmonary weight gain and edema index. RESULTS: Vagotomy promoted pulmonary edema as edema was significantly higher than in the control. This effect was modified by treatment with L-NAME. The highest dose, 39.0 mg/kg, reduced the edema and prolonged the survival of the animals, while at the lowest dose, 0.3 mg/kg, the edema and reduced survival rates were maintained. Aminoguanidine, regardless of the dose inhibited the development of the edema. Its effect was similar to that observed when the highest dose of L-NAME was administered. It may be that the non-selective blockade of cNOS by the highest dose of L-NAME also inhibited the iNOS pathway. CONCLUSION: Our data suggest that iNOS could be directly involved in pulmonary edema induced by vagotomy and cNOS appears to participate as a protector mechanism.

Daño pulmonar agudo asociado a ventilación mecánica / Ventilator associated acute lung injury

Mechanical ventilation plays a central role In the critical care setting; but its use is closely related with some life threatening complications as nosocomial pneumonia and low cardiac performance. One of the most severe complications is called ventilator-associated lung injury (VALI) and it includes: Barotrauma, volutrauma, atelectrauma, biotrauma and oxygen-mediated toxic effects and it is related with an inflammatory response secondary to the stretching and recruitment process of alveoli within mechanical ventilation. The use of some protective ventilatory strategies has lowered the mortality rate 10% approximately.

La importancia de la asistencia mecánica ventilatoria (AMV) en la Unidad de Cuidados Intensivos (UCI) es indiscutible; sin embargo, su uso está ligado con complicaciones como neumonía nosocomial y deterioro del rendimiento cardiaco, que en algunas ocasiones ponen en peligro la vida del enfermo. Una de las complicaciones más graves es el daño pulmonar asociado a la ventilación mecánica (DPVM). El DPVM se caracteriza por la presencia de edema pulmonar rico en proteínas. Se recomienda establecer cierto número de estrategias de protección pulmonar (EPP) para prevenir este tipo de lesión. Una vez instituidas, las EPP han demostrado una disminución de la mortalidad de aproximadamente 10%.

Preparation of a potent anti-scorpion-venom-serum against the venom of red scorpion (Buthus tamalus).

A number of children and adults, especially pregnant women succumb to the sting by red Scorpion (Buthus tamalus) in Konkan region--particularly on the coastal line. No specific antiserum or any other antidote is available to treat a victim of scorpion bite and hence the need to prepare a potent antiserum. Red Scorpion (B. tamalus) venom is a mixture of a number of protein moieties and neurotoxins of low molecular weight. Therefore, the venom is poor in antigenic composition and it is difficult to get antibodies specific to neutralise lethal factor/factors. Using Bentonite as an adjuvant and extending the period of immunization a potent antiserum has been prepared capable of neutralising the lethal factor/factors. In vivo testing carried out in albino mice, guinea pigs, dogs and langurs confirms this finding and shows that the antiserum is quite effective in neutralising the scorpion venom to save the life of envenomated animals.