Duration of Nil Per Os is causal in hospital length of stay following laparoscopic bariatric surgery.

INTRODUCTION: A recent bariatric surgical study demonstrated an inverse relationship of intraoperative hydration with the incidence of extended hospital length of stay (ehLOS: >1 postoperative hospital day). In that study, a post hoc analysis of the preoperative duration of Nil Per Os (NPO) past midnight revealed a significant dose-response association on the incidence of ehLOS, with the lowest incidence (10-12 %) predicted within the 2-5-h NPO interval. As NPO is associated with a state of compensatory dehydration, the objectives of this study were to prospectively examine the role of decreasing preoperative NPO intervals on the incidence of ehLOS in a similar bariatric surgical population and to establish causality of this association. METHODS: Following IRB approval, 168 bariatric surgeries were analyzed following institution of a revised oral water ad libitum policy until 2 h prior to surgery on the incidence of ehLOS. The role of duration of NPO on the incidence of ehLOS was assessed by logistic fit graphs and misclassification rates on the two groups. A statistical process control chart monitored the efficacy of the revised NPO guidelines. RESULTS: There were statistically significant, but not clinical, differences in the incidences of histories of anemia, gastroesophageal reflux disease, previous percutaneous cardiac intervention/percutaneous transluminal coronary artery angioplasty, or preoperative albumin levels between the two groups. There were no perioperative pulmonary aspirations of gastric contents in either group. Following reduction of the oral hydration interval to ≥2 h, a 13-15 % incidence of ehLOS was observed within the 2-5-h NPO interval with similar misclassification rates observed between the two groups. CONCLUSIONS: Allowing bariatric patients access to ad libitum water for up to 2 h prior to surgery decreased the incidence of ehLOS. Comparison of the dose-response curves within the 2-5-h NPO intervals before and after introduction of the revised NPO guidelines was similar and confirms causality.

Role of intraoperative fluids on hospital length of stay in laparoscopic bariatric surgery: a retrospective study in 224 consecutive patients.

BACKGROUND: Studies are unclear regarding optimal intraoperative fluid management during laparoscopic bariatric surgery. The purpose of this 1-year study was to investigate the role of intraoperative fluid administration on hospital length of stay (hLOS) and postoperative complications in laparoscopic bariatric surgery. METHODS: Patient data analyzed included previously reported demographics, comorbidities, and intraoperative fluid administration on the duration of hLOS and incidence of postoperative complications. RESULTS: Logistic regression analysis of demographic and comorbidity variables revealed that BMI (P = 0.0099) and history of anemia (P = 0.0084) were significantly associated with hLOS (C index statistic, 0.7). Lower rates of intraoperative fluid administration were significantly associated with longer hLOS (P = 0.0005). Recursive partitioning observed that patients who received <1,750 ml of intraoperative fluids resulted in longer hLOS when compared to patients who received ≥ 1,750 ml (LogWorth = 0.5). When intraoperative fluid administration rates were defined by current hydration guidelines for major abdominal surgery, restricted rates (<5 ml/kg/h) were associated with the highest incidence of extended hLOS (>1 postoperative day) at 54.1 % when compared to 22.9 % with standard rates (5-7 ml/kg/h) and were lowest at 14.5 % in patients receiving liberal rates (>7 ml/kg/h) (P < 0.0001). Finally, lower rates of intraoperative fluid administration were significantly associated with delayed wound healing (P = 0.03). CONCLUSIONS: The amount of intravenous fluids administered during laparoscopic bariatric surgery plays a significant role on hLOS and on the incidence of delayed wound healing.

Pulmonary and systemic vasodilator responses to the soluble guanylyl cyclase stimulator, BAY 41-8543, are modulated by nitric oxide.

BAY 41-8543 is a nitric oxide (NO)-independent stimulator of soluble guanylyl cyclase (sGC). Responses to intravenous injections of BAY 41-8543 were investigated under baseline and elevated tone conditions and when NO synthase (NOS) was inhibited with N(ω)-nitro-L-arginine methyl ester (L-NAME). Under baseline conditions, intravenous injections of BAY 41-8543 caused small decreases in pulmonary arterial pressure, larger decreases in systemic arterial pressure, and increases in cardiac output. When pulmonary arterial pressure was increased to ∼30 mmHg with an intravenous infusion of U-46619, intravenous injections of BAY 41-8543 produced larger dose-dependent decreases in pulmonary arterial pressure, and the relative decreases in pulmonary and systemic arterial pressure in response to the sGC stimulator were similar. Treatment with L-NAME markedly decreased responses to BAY 41-8543 when pulmonary arterial pressure was increased to similar values (∼30 mmHg) in U-46619-infused and in U-46619-infused plus L-NAME-treated animals. The intravenous injection of a small dose of sodium nitroprusside (SNP) when combined with BAY 41-8543 enhanced pulmonary and systemic vasodilator responses to the sGC stimulator in L-NAME-treated animals. The present results indicate that BAY 41-8543 has similar vasodilator activity in the systemic and pulmonary vascular beds when pulmonary vasoconstrictor tone is increased with U-46619. These results demonstrate that pulmonary and systemic vasodilator responses to BAY 41-8543 are significantly attenuated when NOS is inhibited by L-NAME and show that vasodilator responses to BAY 41-8543 are enhanced when combined with a small dose of SNP in L-NAME-treated animals. The present results are consistent with the concept that pulmonary and systemic vasodilator responses to the sGC stimulator are NO-independent; however, the vasodilator activity of the compound is greatly diminished when endogenous NO production is inhibited with L-NAME. These data show that BAY 41-8543 has similar vasodilator activity in the pulmonary and systemic vascular beds in the rat.

Role of the RhoA/Rho-kinase pathway in the regulation of pulmonary vasoconstrictor function.

Calcium is the major intracellular messenger that triggers smooth muscle contraction. The study of calcium-binding proteins, such as calmodulin and its downstream effectors, reveals critical regulation of smooth muscle contraction by protein kinases and phosphatases. Moreover, the small GTP-binding protein RhoA and its downstream effector protein, Rho-kinase, have been shown to play a novel role in the regulation of smooth muscle contraction. Studies have shown that the activation of Rho-kinase is involved in the development of endothelial dysfunction, inflammation, restenosis, and increased vascular tone in a number of cardiovascular disorders. Because inhibitors of this pathway promote vasodilation independent of the mechanism that increases vasoconstrictor tone, it is our hypothesis that Rho-kinase is constitutively active in regulating vasoconstrictor tone in the pulmonary and systemic vascular beds. Studies in the literature suggest that the RhoA/Rho-kinase pathway has an important role in the pathogenesis of pulmonary hypertension.

Mortality is predicted by Comorbidity Polypharmacy score but not Charlson Comorbidity Index in geriatric trauma patients.

BACKGROUND: Increased life expectancy has resulted in more older patients at trauma centers. Traditional assessments of injuries alone may not be sufficient; age, comorbidities, and medications should be considered. METHODS: 446 older trauma patients were analyzed in two groups, 45-65 years and <65, using Injury Severity Score (ISS), the Charlson Comorbidity Index (CCI), and Comorbidity-Polypharmacy Score (CPS). RESULTS: CCI and CPS were associated with HLOS in patients <65. In patients aged 45-65, only CPS was associated with HLOS. CPS was inversely associated with in-hospital mortality in patients <65, but not patients aged 45-65. CCI score was not associated with in-hospital mortality in either group. CONCLUSION: Increased CCI and CPS were associated with increased HLOS. In patients over 65, increased CPS was associated with decreased mortality. This could be due to return toward physiologic normalcy in treated patients not seen in their peers with undiagnosed or untreated comorbidities.

Nitrates and nitrites in the treatment of ischemic cardiac disease.

The organic nitrite, amyl of nitrite, was initially used as a therapeutic agent in the treatment of angina pectoris, but was replaced over a decade later by the organic nitrate, nitroglycerin (NTG), due to the ease of administration and longer duration of action. The administration of organic nitrate esters, such as NTG, continues to be used in the treatment of angina pectoris and heart failure since the birth of modern pharmacology. Their clinical effectiveness is due to vasodilator activity in large veins and arteries through an as yet unidentified method of delivering nitric oxide (NO), or a NO-like compound. The major drawback is the development of tolerance with NTG, and the duration and route of administration with amyl of nitrite. Although the nitrites are no longer used in the treatment of hypertension or ischemic heart disease, the nitrite anion has recently been discovered to possess novel pharmacologic actions, such as modulating hypoxic vasodilation, and providing cytoprotection in ischemia-reperfusion injury. Although the actions of these 2 similar chemical classes (nitrites and organic nitrates) have often been considered to be alike, we still do not understand their mechanism of action. Finally, the nitrite anion, either from sodium nitrite or an intermediate NTG form, may act as a storage form for NO and provide support for investigating the use of these agents in the treatment of ischemic cardiovascular states. We review what is presently known about the use of nitrates and nitrites including the historical, current, and potential uses of these agents, and their mechanisms of action.

Advances in perioperative pain management: use of medications with dual analgesic mechanisms, tramadol & tapentadol.

Recovery from ambulatory surgical procedures can be limited by postoperative pain. Inadequate analgesia may delay or prevent patient discharge and can result in readmission. More frequently, postoperative pain produces discomfort and interrupts sleep, contributing to postoperative fatigue. The development of effective analgesic regimens for the management of postoperative pain is a priority especially in patients with impaired cardiorespiratory, hepatic, or renal function. Tramadol and tapentadol hydrochloride are novel in that their analgesic actions occur at multiple sites. Both agents are reported to be mu-opioid receptor agonists and monoamine-reuptake inhibitors. In contrast to pure opioid agonists, both drugs are believed to have lower risks of respiratory depression, tolerance, and dependence. The Food and Drug Administration has approved both drugs for the treatment of moderate-to-severe acute pain in adults. This article provides an evidence-based account of the role of tramadol and tapentadol in modern clinical practice.

The Reemergence of Nitrite as a Beneficial Agent in the Treatment of Ischemic Cardiovascular Diseases.

Nitrite was a therapeutic agent used in the treatment of angina pectoris and hypertension, but was replaced by nitroglycerin. However, nitrite has recently been rediscovered following observations that this anion possesses novel pharmacologic actions such as producing vasodilation, modulating hypoxic vasodilation, and providing cytoprotection in ischemia-reperfusion injury. Moreover, recent observations in animal and human studies have demonstrated that the reduction of nitrite to vasoactive nitric oxide occurs through both enzymatic and non-enzymatic processes. These findings suggest that nitrite may act as a storage form for nitric oxide and provide support for investigating the use of nitrite in the treatment of ischemic disease states including pulmonary hypertension.

History of right heart catheterization: 100 years of experimentation and methodology development.

The development of right heart catheterization has provided the clinician the ability to diagnose patients with congenital and acquired right heart disease, and to monitor patients in the intensive care unit with significant cardiovascular illnesses. The development of bedside pulmonary artery catheterization has become a standard of care for the critically ill patient since its introduction into the intensive care unit almost 40 years ago. However, adoption of this procedure into the mainstream of clinical practice occurred without prior evaluation or demonstration of its clinical or cost-effectiveness. Moreover, current randomized, controlled trials provide little evidence in support of the clinical utility of pulmonary artery catheterization in the management of critically ill patients. Nevertheless, the right heart catheter is an important diagnostic tool to assist the clinician in the diagnosis of congenital heart disease and acquired right heart disease, and moreover, when catheter placement is proximal to the right auricle (atria), this catheter provides an important and safe route for administration of fluids, medications, and parenteral nutrition. The purpose of this manuscript is to review the development of right heart catheterization that led to the ability to conduct physiologic studies in cardiovascular dynamics in normal individuals and in patients with cardiovascular diseases, and to review current controversies of the extension of the right heart catheter, the pulmonary artery catheter.