Reduction of renal function during mechanical ventilation of healthy lungs in an animal biomodel.

OBJECTIVES: To identify factors involved in reno-pulmonary interactions during mechanical ventilation. MATERIALS AND METHODS: The study included a total of 25 domestic piglets. The animals were divided into three groups based on different strategies of ventilation. Group A; spontaneously breathing piglets; group B animals ventilated with tidal volume of 6 ml.kg-1 and group C with animals ventilated with tidal volume 10 ml.kg-1. Clinical monitoring and laboratory tests were performed for all groups at baseline and then at 1 hour and 12 hours for groups B and C. Ventilation indices, hemodynamics, urine output, creatinine clearance, glomerular filtration index, fractional excretion of sodium, free water clearance and tissue samples were recorded. The data obtained were statistically analysed. RESULTS: Lower creatinine clearance and renal indices were seen in group B (p < 0.05) and in group C (p < 0.001) at 1 hour, and a difference in urine output for group C (p < 0.01) compared to group A was observed. At 12 hours, there was a further reduction in creatinine clearance and renal indices for group B (p < 0.05) and group C (p < 0.01). The lung mechanics and hemodynamics were not significantly influenced. CONCLUSIONS: The study showed a causal relationship between renal dysfunction and positive pressure mechanical ventilation with respect to tidal volume and time (Tab. 4, Fig. 2, Ref. 17).

Induced therapeutic hypothermia following cardiac arrest in children.

OBJECTIVE: Evidence-based medicine currently dictates that in children, the controlled hypothermia may be applied only to the first degree and only in cases of neonatal encephalopathy and acute brain injury. Current recommendations are limited in terms of indication as well as by their very low degree of relevance (47.1%). DATA SOURCE: The conclusions of published clinical and experimental studies, and ultimately the ongoing study of our clinical work. In our study, we monitored the core body temperature, brain bioelectrical potentials and infarction, heart rate, systemic venous and arterial pressure, cardiac output, hourly diuresis, and haemostasis parameters. STUDY SELECTION: Distinct designs of clinical and experimental studies make it difficult to compare their outputs. DATA SYNTHESIS: The aim of this article is to expand our current knowledge of resuscitation care in children as well as that of the use of therapeutic hypothermia. The introduction of this method into routine pediatric clinical practice is hindered by lack of an explicitly defined therapeutic protocol. CONCLUSION: The method of therapeutic hypothermia is not a predictor of survival but its proper implementation can be the key to the recovery of functions of body organs and systems after successful cardiopulmonary resuscitation. Unfortunately, this method is associated with adverse effects, namely with myocardial depression during the induction phase, and life-threatening complications after bringing the core of body to normal temperature. To increase the patient safety we have developed a safe strategy. Our protocol provides a relatively rapid induction, short interval of active cooling and passive rewarming over a long period of time (Tab. 3, Fig. 1, Ref. 34). Full Text in free PDF www.bmj.sk.

Total body response to mechanical ventilation of healthy lungs: an experimental study in piglets.

The objective of our study was to assess the influence of mechanical ventilation on healthy body organs. Fifteen piglets (aged 6 weeks, 19-27 kg) were anesthetized, instrumented, and divided into three groups: Group A - spontaneously breathing, group B - mechanically ventilated with tidal volume 6 ml/kg, and group C - ventilated with tidal volume 10 ml/kg for 12 hours. The parameters of lung, heart, liver and kidney functions neurohumoral regulation and systemic inflammatory reaction were recorded initially (time-1) and after 12 hours (time-12) of mechanical ventilation. At the onset of experiment (time-1) the levels of soluble adhesive molecules were higher (CAM; P<0.01), glomerular filtration index and free water clearance were lower (P<0.05) in both ventilated groups than in group A. Right ventricle myocardial performance index was higher (RIMP; P<0.05) in group C when compared with group A. Levels of CAM (P<0.05) and creatinine clearance (P<0.01) were higher, free water clearance was lower (P<0.05) in group C when compared to group B. At time-12 the RIMP (P<0.05) and levels of CAM were increased (P<0.01), creatinine clearance was decreased (P<0.05) in both ventilated groups compared to the same parameter at time-1. Ventilation index was higher (P<0.05), and hypoxemic index was lower (P<0.01) in group C when compared to group B. In conclusion, this study showed that mechanical ventilation induced changes compatible with early inflammatory response in healthy animals. Higher tidal volumes had detrimental effect on ventilatory parameters, reduced myocardial performance and potentiated adverse reaction of other organs.

Signaling molecules for early detection of adverse interactions during mechanical ventilation in animal models.

AIM: The early identification of adverse interactions during mechanical ventilation, investigated by multiplexed immunoanalysis. MATERIALS AND METHODS: Twenty piglets (average age 7 weeks, weight 23 kg) were intubated and divided into groups: A, spontaneously breathing; B, protectively ventilated; C, ventilated with injurious strategy; D, ventilated with lung disability. At the 1st hour (time-1) and 12th hour (time-2) of the study, brain natriuretic peptide (BNP), intercellular cell adhesion molecules (ICAM-1), vascular cell adhesion molecules (VCAM-1), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (Il-6) were analyzed in the blood. RESULTS: The injurious ventilated group C exhibited an increase in both cell adhesion molecules (p<0.01), TNF-alpha and BNP (p<0.05) at time-1, and at time-2 further increases (p<0.05). In group D, an increase in ICAM-1 and BNP (p<0.05) at time-1, and increases in Il-6 and ICAM-1 (p<0.05) at time-2, with notable decreases in urine output were observed. Overall, the lung damage correlated with TNF-alpha (r=0.904), Il-6 (r=0.740), and ICAM-1 (r=0.756) levels. CONCLUSION: All five monitored molecules quickly and reliably signaled adverse interactions.