Effects of Arginine Vasopressin on Oxygenation and Haemodynamics during One-Lung Ventilation in an Animal Model

In a case of arterial hypotension during one-lung ventilation, haemodynamic support may be required to maintain adequate mean arterial pressure. Arginine vasopressin, a potent systemic vasoconstrictor with limited effects on the pulmonary artery pressure, has not been studied in this setting. Twelve female pigs were anaesthetised and ventilated and arterial, central venous and pulmonary artery catheters were inserted. A left-sided double lumen tube was placed via tracheostomy and one-lung ventilation was initiated. The animals were in the left lateral position, with the left lung ventilated and right lung collapsed. Respiratory and haemodynamic values were recorded before and during a continuous infusion of arginine vasopressin sufficient to double the mean arterial pressure. The arginine vasopressin caused a decrease in cardiac output (3.8±1.1 vs. 2.7±0.7 l/min, P <0.001) and mixed-venous oxygen tension (39.1±5.8 vs. 34.4±5 mmHg, P=0.003). Pulmonary artery pressure was unchanged (24±2 vs. 24±3 mmHg, P=0.682). There was no effect of the arginine vasopressin on arterial oxygen tension (226±106 vs. 231±118 mmHg, P=0.745). However, there was a significant decrease in shunt fraction (28.3±6.2 vs. 24.3±7.8%, P=0.043) and a significant proportional increase in perfusion of the ventilated lung (78.8±9.5 vs. 85.5±7.9%, P=0.036). In our animal model of one-lung ventilation, doubling mean arterial pressure by infusion of arginine vasopressin significantly affected global haemodynamics, but had no influence on systemic arterial oxygen tension.

Präklinische transtracheale Notfallventilation

INTRODUCTION

Prehospital transtracheal ventilation via a needle cricothyroidotomy may be lifesaving in cannot-intubate-cannot-ventilate situations. A self-made device consisting of a three-way stopcock placed between a transtracheal airway catheter and an oxygen supply was constructed and the effectiveness of the device was compared with a hand-triggered emergency jet generator in animal experiments.

MATERIALS AND METHODS

An emergency transtracheal airway catheter was inserted into the trachea of 10 anesthetized pigs (18-35 kgbw) and a situation of partial expiratory airway obstruction was established. All pigs were ventilated in a randomized order via the transtracheal airway catheter with the hand-triggered emergency jet injector and the self-made device for 15 min each.

RESULTS

With both devices satisfactory oxygenation and ventilation was achieved in all animals.

CONCLUSIONS

The efficacy of the self-made device during the experiment was comparable with the efficacy of the hand-triggered emergency jet injector.

Respiratorische Insuffizienz und pulmonale Fibrose als Spätfolge einer Chemotherapie - induziert durch Sauerstoffexposition

Pulmonary fibrosis (PF) may develop following successful chemotherapy for malignancy, even if such therapy is not combined with radiotherapy. Bleomycin, which is known to induce acute pneumonitis and lung fibrosis, is especially associated with chemotherapy-induced PF, and bleomycin-induced pulmonary fibrosis can occur more than five years after such therapy. Additionally, supplemental oxygen therapy can trigger the onset of pneumonitis and lethal PF in patients who have previously received bleomycin therapy. Careful assessment of lung function via spiroergometry and arterial blood gas analysis during exercise are required if the administration of supplemental oxygen is considered. Two case reports reveal the potential lethal risk of oxygen for patients who have been treated with bleomycin: (1) a patient with successfully resected and treated basal tongue carcinoma and (2) a patient in remission after being treated for non-Hodgkin lymphoma. Single and double lung transplantation is the only therapeutic option for patients with severe, oxygen-induced PF and should be included as an indication for lung transplantation. Early recognition of pulmonary diffusion abnormalities and establishing a risk profile, as well as consequent monitoring of pulmonary function, may help to avoid or at least reduce the risk of PF induced by oxygen therapy when administered to patients who have previously been given bleomycin.

Lung perfusion affects preload assessment and lung water calculation with the transpulmonary double indicator method

OBJECTIVES

The transpulmonary double indicator method uses intra- and extravascular indicators to calculate cardiac output, intrathoracic blood volume, global end-diastolic volume, and extravascular lung water content. Since lung perfusion may be of importance during these measurements, we studied the effects of pulmonary blood flow occlusion on measurements obtained with this method.

SETTING

Experimental animal facility of a University department.

METHODS AND INTERVENTIONS

In seven pigs, the branch of the pulmonary artery perfusing the lower and middle lobe of the right lung was occluded. Measurements before, during, and after the occlusion were made with a pulmonary artery catheter and a commonly used transpulmonary double indicator catheter and device.

MEASUREMENTS AND RESULTS

Occlusion of the right lower and middle lobe branch of the pulmonary artery increased mean pulmonary pressure (before occlusion: 24+/-1, during occlusion: 32+/-2, after reopening 25+/-1 mmHg; P<0.05), increased right ventricular end-diastolic volume (172+/-34, 209+/-21, 174+/-32 ml, respectively; P<0.05), decreased intrathoracic blood volume (998+/-39, 894+/-48, 1006+/-49 ml, respectively; P<0.05), and decreased extravascular lung water (7.2+/-0.5, 4.2+/-0.4, 6.9+/-0.4 ml/kg, respectively; P<0.05) without causing significant changes in cardiac output. All changes were reversible upon reopening the vessel.

CONCLUSIONS

These data show that the transpulmonary double indicator method may underestimate extravascular lung water and right ventricular preload when the perfusion to parts of the lung is obstructed.