Negative pressure pulmonary hemorrhage

Edema e hemorragia pulmonar por pressão negativa associados à obstrução das vias aéreas superiores

O edema pulmonar por pressão negativa associado à hemorragia como manifestação de obstrução das vias aéreas superiores é um problema incomum com potencial risco de morte. O principal mecanismo fisiopatológico envolvido é a geração de uma acentuada pressão negativa intratorácica que eleva tanto o volume vascular como a pressão transmural capilar pulmonar, causando risco de ruptura da membrana alvéolo-capilar. Relatamos o caso de um paciente do sexo masculino com hemorragia alveolar difusa após obstrução aguda das vias aéreas superiores causada pela formação de um abscesso cervical e mediastinal decorrente do implante de uma órtese traqueal metálica. O paciente foi tratado com drenagem do abscesso, antibioticoterapia e ventilação mecânica com pressão positiva. Este artigo enfatiza a importância de incluir essa entidade no diagnóstico diferencial da lesão pulmonar aguda após procedimentos que envolvam a manipulação das vias aéreas superiores.

Cytokine release following recruitment maneuvers

BACKGROUND

There are reports of rigors and/or clinical deterioration following recruitment maneuvers (RMs), leading us to question whether the use of sustained high-pressure inflation could lead to release of inflammatory mediators.

METHODS

Prospective cohort study of 26 patients with ARDS receiving mechanical ventilation. A single RM was performed during which the mean airway pressure was increased to 40 cm H2O and held constant for a period of 30 s. The concentration of nine cytokines (interleukin [IL]-1, IL-6, IL-8, IL-10, tumor necrosis factor [TNF]-alpha, Fas ligand, vascular endothelial growth factor, TNF receptor 1, TNF receptor 2) was measured longitudinally at three time points: prior to initiation of the RM, 5 min after the RM, and 60 min after the RM.

RESULTS

RMs were tolerated well from a hemodynamic perspective. Oxygenation improved as reflected by an increased Pao2/fraction of inspired oxygen (Fio2) ratio from 140+/-49 at baseline to 190+/-78 (mean+/-SD) at 5 min after the RM (p=0.01). At 60 min, the increase in Pao2/Fio2 ratio, to 172+/-76, was no longer significant (p=0.1). There were no important changes in the levels of any of the measured cytokines at 5 min or 60 min following RM as compared with the baseline levels.

CONCLUSIONS

The results of our study demonstrate that recruitment maneuvers are well tolerated in patients with ARDS. Our data suggest no major hemodynamic or immunologic evidence of deterioration within the first hour of RM. In particular, cytokines, previously related to worsening lung injury and distal organ failure in patients with ARDS, are not elevated by use of an RM. Registered at: www.clinicaltrials.gov as NCT00127491.

Computer simulation of human breath-hold diving: cardiovascular adjustments

The world record for a sled-assisted human breath-hold dive has surpassed 200 m. Lung compression during descent draws blood from the peripheral circulation into the thorax causing engorgement of pulmonary vessels that might impose a physiological limitation due to capillary stress failure. A computer model was developed to investigate cardiopulmonary interactions during immersion, apnea, and compression to elucidate hemodynamic responses and estimate vascular stresses in deep human breath-hold diving. The model simulates active and passive cardiovascular adjustments involving blood volumes, flows, and pressures during apnea at diving depths up to 200 m. Redistribution of blood volume from peripheral to central compartments increases with depth. Pulmonary capillary transmural pressures in the model exceed 50 mm Hg at record depth, producing stresses in the range known to cause alveolar capillary damage in animals. Capillary pressures are partially attenuated by blood redistribution to compliant extra-pulmonary vascular compartments. The capillary pressure differential is due mainly to a large drop in alveolar air pressure from outward elastic chest wall recoil. Autonomic diving reflexes are shown to influence systemic blood pressures, but have relatively little effect on pulmonary vascular pressures. Increases in pulmonary capillary stresses are gradual beyond record depth.

[Haemoptysis after anesthesia]

Postobstructive pulmonary oedema is a complication after extubation that occurs rarely . It can be associated with haemoptysis. We report two cases of haemoptysis occuring in ASA 1 otherwise healthy patients who underwent uncomplicated anaesthesia. Understanding of the mechanism and prompt treatment lead to rapid recovery of this dramatic complication.

Negative-pressure pulmonary edema after routine septorhinoplasty: discussion of pathophysiology, treatment, and prevention

OBJECTIVE

To provide rhinologic surgeons with an understanding of acute negative-pressure pulmonary edema (NPPE) and its treatment.

DESIGN

Case report and literature review of all published adult cases of NPPE. Patient factors, anesthetic variables, and outcomes are assessed.

RESULTS

A total of 146 cases in 45 case reports and series were compiled. There was approximately a 2:1 male-female patient ratio. The average age of the patients was 33 years. Fifty percent of patients had surgery on the upper aerodigestive tract, and 8% had intranasal surgery. No patients received laryngotracheal anesthesia, and 5 of the 146 received intravenous lidocaine prior to extubation. One patient had NPPE following laryngeal mask airway treatment, and 2 patients experienced this complication after conversion from monitored anesthesia care to general endotracheal anesthesia; 33.5% of patients were treated with continuous positive airway pressure alone, while 66.5% required intubation and mechanical ventilation. The average time to resolution was 11.75 hours. Three patients died.

CONCLUSIONS

It is known that surgical procedures involving the upper aerodigestive tract have a higher risk of NPPE than other procedures. Rapid diagnosis and treatment is necessary to achieve early resolution and avoid significant patient morbidity. A thorough understanding is integral to the practice of nasal and paranasal sinus surgery, especially with the rising use of outpatient and office-based surgical suites. Therefore, we present a review of pathophysiologic mechanisms, possible risk factors, treatment options, and potential steps that can be taken to minimize this potentially devastating complication of general anesthesia.

Œdème aigu du poumon postobstructif après extubation trachéale au réveil d'une anesthésie générale

We report two cases of postobstructif pulmonary oedema occurring after extubation at the recovery of general anaesthesia and presenting some similarities. The young age of the patient and the occurrence of upper airway obstruction after extubation, as well as the radiologic nondependent distribution of alveolar pattern are typical. The underlying pathophysiology seems to be the mechanical disruption of the alveolar-capillary membrane.

Negative pressure pulmonary oedema in the medical intensive care unit

OBJECTIVE

Negative pressure pulmonary oedema (NPPE) occurring in the medical intensive care unit (MICU) is an uncommon, probably under-diagnosed, but life-threatening condition.

DESIGN

Retrospective data collection.

SETTING

Medical intensive care unit in a 1,500-bedded tertiary care hospital.

PATIENTS AND PARTICIPANTS

Five patients were diagnosed between January 1998 and January 2002.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Five patients were diagnosed to have NPPE from different aetiologies. These were acute epiglottitis, post-stenting of right bronchus intermedius stenosis, strangulation, compression from a goitre and one patient developed diffuse alveolar haemorrhage after biting the endotracheal tube during recovery from anaesthesia. All patients responded rapidly to supplemental oxygen, positive pressure ventilation and correction of underlying aetiologies. Pulmonary oedema resolved rapidly.

CONCLUSIONS

There is a large spectrum of aetiologies causing NPPE in the medical intensive care unit.

Removal of obstructing blood clot from the lower airway: an alternative suction technique

Clotted blood or organised thrombus in the lower airway may present clinicians with life-threatening airway obstruction or pulmonary collapse. An alternative suction technique is described, which applies suction directly to a tracheal tube.

Hemoptysis provoked by voluntary diaphragmatic contractions in breath-hold divers

Pulmonary barotrauma of descent (lung squeeze) has been described in breath-hold divers when the lung volume becomes smaller than the residual volume (RV), with the effect of increased ambient pressure. However, the ratio between the total lung capacity and the RV is not the only factor that plays a role in the lung squeeze. Blood shift into the thorax is another important factor. We report three cases of hemoptysis in breath-hold divers who dove for spear fishing in shallower depths than usual. All of the divers performed voluntary diaphragmatic contractions at the beginning of their ascent, while their mouths and noses were closed. We suggest that the negative intrathoracic pressure due to the forced attempt to breathe in with voluntary diaphragmatic contractions contributes to alveolar hemorrhage, since it may damage the pulmonary capillaries.

Pulmonary hemorrhage in association with negative pressure edema in an intubated patient

Negative pressure pulmonary edema due to upper airway obstruction following extubation is a well-recognized problem. However, frank pulmonary hemorrhage as a manifestation of upper airway obstruction is uncommon. We report a case of significant pulmonary hemorrhage and negative pressure pulmonary edema in an intubated patient. Bronchoscopy showed a collection of blood in the right lower lobe of the lungs, suggesting a localized source of bleeding. There have been two previously reported cases of pulmonary hemorrhage after upper airway obstruction. One suggested that the bleeding was due to damage to the pulmonary capillaries, the other that it was due to disruption of the bronchial vessels. We feel that in our case there was some indication that the pulmonary bleeding was a result of bronchial vessel damage. A number of factors might have been involved in its development, including negative pulmonary pressure, recent respiratory tract infection, and positive airways pressure (due to coughing).

General pediatric emergencies. Acute pulmonary edema

This article focuses on three types of acute pulmonary edema in children: negative-pressure pulmonary edema, neurogenic pulmonary edema, and cardiogenic pulmonary edema.

Postobstructive pulmonary oedema--a case series and review

Six cases of post-extubation pulmonary oedema in otherwise healthy patients are reported. All were preceded by an episode of laryngospasm and followed a clinical course similar to that previously documented in cases of post-obstructive pulmonary oedema. Frank haemoptysis was a feature of five of the presentations. One patient was reintubated and ventilated, two were admitted to the intensive care unit for mask CPAP, one was managed with CPAP in the recovery ward and two with supplemental oxygen only. All cases resolved fully within 24 hours. Some evidence points to the syndrome being the result of airway bleeding rather than true pulmonary oedema. The literature suggests that it occurs more commonly than is generally thought, with a frequency of 0.05 to 0.1% of all anaesthetics, and is often unrecognised or misdiagnosed. Most cases occur in the early postoperative period, so anaesthetists are well placed to witness, investigate and manage this interesting condition.