ABSTRACT
BACKGROUND AND AIMS: Mechanical ventilation (MV) with high tidal volume (Vt.) may induce or aggravate lung injury in critically ill patients. It might also cause an overwhelming systemic inflammation leading to acute lung injury (ALI), diffuse alveolar damage (DAD) and multiple organ failure (MOF) with subsequent high mortality. The objective of this study was to compare the effects of different Vt. on the inflammatory markers of the broncho-alveolar lavage (BAL) fluid and lung biopsy in a group of animal model (Beagle dogs). METHODS: A two-phased prospective study involving 30 Beagle dogs (15 dogs/phase), each phase divided into three groups (each 5 dogs/group). In the first phase each group received MV with Vt. of 8 (low), 10 (normal, control group), and 12 (high) ml/kg body weight (b.w.) respectively. BAL fluid was obtained at the time of induction of anesthesia immediately following tracheal intubation and one hour later following MV to count the macrophages, neutrophils and lymphocytes. In the second phase of the experiment, in addition to obtaining (BAL) fluid similar to the phase one, mini thoracotomy and lung biopsy obtained from the upper lobe of the right lung at same timings for histopathological examination study. Mann-Whitney-Wilcoxon test was used for statistical analysis of the data obtained. RESULTS: BAL fluid analysis showed increase in the counts of macrophages and lymphocytes with Vt. of 12 ml/kg b.w. compared to the control group (10 ml/kg b.w.) (P < 0.05). in the second phase, similar findings obtained. The histopathological study of the lung tissue obtained in the second phase of the study from the group that received a high Vt. of 12 ml/kg b.w. showed significant inflammatory changes with presence of neutrophil infiltration and edema in the bronchial wall compared to the control group (10 ml/kg b.w.) (P < 0.05). CONCLUSIONS: The use of high Vt. in ventilated animal lung model may increase the risk of inflammation and subsequent damage in healthy lungs, these findings may help physicians to avoid using high Vt. in short-term mechanically ventilated patients in the operating room setting.
ABSTRACT
CONTEXT: Tracheal intubation is frequently facilitated with sevoflurane induction without the use of muscle relaxants in children. AIM: The aim of this study was to compare the effects of two different doses of propofol preceded by a fixed dose of fentanyl during sevoflurane induction on quality of tracheal intubation in children. SETTINGS AND DESIGN: This was a prospective randomized study. SUBJECTS AND METHODS: Ninety American Society of Anesthesiologists I-II children aged 2-6 years were randomly assigned to one of two equal groups to receive 2 µg/kg of fentanyl with 2 mg/kg of propofol (Group I) or 2 µg/kg of fentanyl with 3 mg/kg of propofol (Group II) during sevoflurane induction. The intubating conditions and hemodynamic responses were evaluated. The time from sevoflurane induction to loss of consciousness, to intravenous line insertion, and to intubation was measured. The occurrence of any adverse effect was recorded. STATISTICAL ANALYSIS USED: Results were analyzed using Student's t-test, paired t-test, and Chi-square test. P < 0.05 was considered statistically significant. RESULTS: The incidence of excellent intubating conditions was achieved more significantly in Group II (41/45 patients, 91%) than that in Group I (31/45 patients, 69%) (P = 0.008) (95% confidence interval [CI] =0.39-0.8). Whereas, there were no significant differences between the two groups in terms of the overall acceptable intubating conditions in Group I (40/45 patients, 89%) and Group II (43/45 patients, 96%) (P = 0.81) (95% CI = 0.71-1.31). No patient developed any adverse effect. CONCLUSION: The administration of 3 mg/kg propofol preceded by 2 µg/kg fentanyl provided a higher proportion of excellent intubating conditions compared with 2 mg/kg propofol preceded by 2 µg/kg fentanyl during sevoflurane induction in children without muscle relaxants.
