Effect of prophylactic bronchodilator treatment with i.v. carperitide on airway resistance and lung compliance after tracheal intubation

The effect of tulobuterol patches on the respiratory system after endotracheal intubation

Background

Endotracheal intubation during anesthesia induction may increase airway resistance (R_aw) and decrease dynamic lung compliance (C_dyn). We hypothesized that prophylactic treatment with a transdermal β2-agonist tulobuterol patch (TP) would help to reduce the risk of bronchospasm after placement of the endotracheal tube.

Methods

Eighty-two American Society of Anesthesiologists (ASA) category I or II adult patients showing obstructive patterns were divided randomly into a control and a TP group (n = 41 each). The night before surgery, a 2-mg TP was applied to patients in the TP group. Standard monitors were recorded, and target controlled infusion (TCI) with propofol and remifentanil was used for anesthesia induction and maintenance. Simultaneously, end-tidal carbon dioxide, R_aw, and C_dyn were determined at 5, 10, and 15 min intervals after endotracheal intubation.

Results

There was no significant difference in demographic data between the two groups. The TP group was associated with a lower R_aw and a higher C_dyn, as compared to the control group. R_aw was significantly lower at 10 min (P < 0.05) and 15 min (P < 0.01), and C_dyn was significantly higher at 5 min (P < 0.05) and 15 min (P < 0.01) in the TP group. A trend towards a lower R_aw was observed showing a statistically significant difference 5 min after endotracheal intubation (P < 0.01) in each group.

Conclusions

Prophylactic treatment with TP showed a bronchodilatory effect through suppressing an increase in R_aw and a decrease in C_dyn after anesthesia induction without severe adverse effects.

Natriuretic peptides and therapeutic applications

Since the discovery of atrial natriuretic factor by de Bold et al., there has been tremendous progress in our understanding of the physiologic, diagnostic and therapeutic roles of the natriuretic peptides (NPs) in health and disease. Natriuretic peptides are endogenous hormones that are released by the heart in response to myocardial stretch and overload. Three mammalian NPs have been identified and characterized, including atrial natriuretic peptide (ANP or atrial natriuretic factor), B-type natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). In addition, Dendroaspis natriuretic peptide (DNP) has been isolated from the venom of Dendroaspis angusticeps (the green mamba snake), and urodilatin from human urine. These peptides are structurally similar and they consist of a 17-amino-acid core ring and a cysteine bridge. Both ANP and BNP bind to natriuretic peptide receptor A (NPR-A) that are expressed in the heart and other organs. Activation of NPR-A generates an increase in cyclic guanosine monophosphate, which mediates natriuresis, inhibition of renin and aldosterone, as well as vasorelaxant, anti-fibrotic, anti-hypertrophic, and lusitropic effects. The NP system thus serves as an important compensatory mechanism against neurohumoral activation in heart failure. This provides a strong rationale for the use of exogenous NPs in the management of acutely decompensated heart failure. In this article, the therapeutic applications of NPs in the acute heart failure syndromes are reviewed. Emerging therapeutic agents and areas for future research are discussed.