Analysis of Airway Management for Cesarean Delivery: Use of Risk and Proportion Differences.

OBJECTIVES: Securing the parturient airway is essential during general anesthesia for cesarean delivery. The purpose of this study was to compare inferior airway views provided by the use of three commonly available laryngoscopy blades-Macintosh, Miller, or Glidescope Mac-Style-to the incidence of difficult orotracheal intubation. METHODS: Following institutional review board approval, data from 449 electronic medical records in parturients undergoing general anesthesia for cesarean delivery were extracted during a 6-year period. The association of these blades with difficult orotracheal intubation was analyzed with risk and proportion differences measures of effect size. RESULTS: The overall incidence of difficult orotracheal intubation was 4.2% (95% confidence interval 2.7 - 6.5%), with 6 failed orotracheal intubations (5 laryngeal mask airways rescues and 1 mask rescue). Clinically important increases in risk differences for difficult orotracheal intubation were observed in parturients with restricted mouth openings, modified Mallampati III and IV views, and reduced thyromental distances. When modified Cormack-Lehane views were grouped into III and IV versus I and II cohorts; proportion differences for difficult orotracheal intubation were dependent upon the type of blade used, with the Miller blade providing the lowest proportion difference. CONCLUSIONS: Miller blade laryngoscopy provided the lowest proportion difference for difficult orotracheal intubation during general anesthesia for cesarean delivery. Miller blade laryngoscopy provides effective procurement of the parturient airway.

Novel Opiate-Free Anesthetic Technique for Major Urologic Procedures.

OBJECTIVES: We postulated that an opiate-free (OF) general anesthesia (GA) technique could adequately control a patient's pain without adversely affecting recovery. We compared patients undergoing major urologic procedures with and without opiate-based GA. METHODS: A propensity-matched analysis was performed comparing hospital length of stay, postoperative nausea and vomiting, ileus occurrence, postanesthesia care unit, and total opiate consumption, as well as sedation and hemodynamic variables. The data are expressed as medians and were analyzed with the Wilcoxon rank-sum test. P < 0.05 indicate statistical significance. RESULTS: In total, 166 patients were evaluated in both the OF group and the opiate-based treatment group. American Society of Anesthesiologists classification and age were comparable, with most surgeries being laparoscopic and confined to the bladder, kidney, and prostate gland. The median opiate consumption in morphine equivalents in the postanesthesia care unit was 7.7 mg (range 5-11.7 mg) for the OF cohort versus 11.7 mg (range 5-17.3 mg) for the control group (P < 0.001). Similarly, the median total postoperative opiate consumption in morphine equivalents was 23.9 mg (range 13.8-42.4 mg) for the OF group compared with 32.1 mg (range 17.38-57.51 mg) for the control group (P = 0.0081). The median hospital length of stay for the OF group was 1.4 days (range 1.2-2.3 days) versus 1.3 days (range 1.2-2.4 days) for the control group (P = 0.8466). CONCLUSIONS: There was a statistically significant difference in opiate consumption postoperatively for patients who underwent an OF technique compared with a conventional opiate-based technique. This technique appears to be a possible alternative approach, without any apparent untoward consequences during admission.

The Effect of the IPACK Block on Pain After Primary TKA: A Double-Blinded, Prospective, Randomized Trial.

BACKGROUND: The purpose of this study was to determine if infiltration of local anesthetic between the interspace between the popliteal artery and capsule of the knee (IPACK) provides benefit in total knee arthroplasty. METHODS: Patients were randomized into continuous adductor canal block with IPACK block or continuous adductor canal block with sham subcutaneous saline injection. Only the anesthesiologist performing the block was aware of randomization status. After surgery, a blinded assessor recorded opioid consumption, pain scores, and gait distance. RESULTS: There were 35 patients in the IPACK group and 34 in the NO IPACK group. There was no difference demographically between the groups. In the postanesthesia care unit (PACU), the average (P = .0122) and worst (P = .0168) pain scores at rest were statistically lower in the IPACK group. There was no difference in the pain scores during physical therapy (P = .2080). There was no difference in opioid consumption in the PACU (P = .7928), or at 24 hours (P = .7456). There was no difference in pain scores on POD 1 in the AM (P = .4597) or PM (P = .6273), or in the walking distance (P = .5197). There was also no difference in length of stay in the PACU (P = .9426) or hospital (P = .2141). CONCLUSION: The IPACK group had lower pain scores at rest in the PACU, but this is likely not clinically significant. The routine use of the IPACK is not supported by the results of this study. There may be indications for the use of the IPACK block as a rescue block or in patients who have contraindications to our standard multimodal treatment regimen or in patients with chronic pain or opioid dependence.

A Dose-Response Analysis of Crystalloid Administration during Esophageal Resection.

OBJECTIVES: The purpose of this retrospective study was to investigate the role of intraoperative crystalloid administration on postoperative hospital length of stay (phLOS) and on the incidence of previously reported adverse events in 100 consecutive patients who underwent esophageal resection. METHODS: The role of previously reported patient demographics, clinical characteristics, and intraoperative crystalloid administration on the duration of phLOS underwent statistical screening criteria for multivariable analysis, including the use of an instrumental variable to measure the role of unmeasured confounders on phLOS. Tests to assess the likelihood of causality also were performed. RESULTS: When the volumes of intraoperative crystalloids were expressed as dose-response relationships to outcomes, progressive decreases in phLOS, variances in phLOS, and the incidences of unplanned surgical intensive care unit admission, postoperative pneumonia, respiratory failure requiring orotracheal intubation, nonsinus cardiac dysrhythmias, and anastomotic leak were observed. Intraoperative transfusion of packed red blood cells greatly increased the duration of phLOS, which was not associated with estimated blood loss, length of surgical operation, or unplanned surgical intensive care unit admission. Instrumental variable analysis revealed no significant influence on phLOS. Causality tests supported the role of intraoperative crystalloid administration in reducing the duration and variance of phLOS. CONCLUSIONS: A dose-response relationship was clinically observed between intraoperative crystalloid administration and the duration and variance of phLOS and with commonly reported postoperative adverse events. Intraoperative transfusion of packed red blood cells greatly increased phLOS that was not associated with the severity of the surgical operation. Instrumental variables and tests for causality further supported the role of intraoperative crystalloid administration in reducing the duration and variance of phLOS.

Predictive model and risk factors associated with a revised definition of early allograft dysfunction in liver transplant recipients.

INTRODUCTION: Early allograft dysfunction (EAD) is a well-defined clinical syndrome that reflects overall graft function within the first week after transplant. The aim of this study was to further refine the definition for EAD. METHOD: In this study, 1124 patients were included for analysis. Logistic regression was performed to identify markers of liver injury associated with 6-month patient and graft failure. RESULTS: Recursive partitioning identified cut-points for ALT/AST > 3000/6000 IU/dL observed within first week, with bilirubin ≥ 10 mg/dL and INR ≥ 1.6 on postoperative day 7 for the revised EAD model. The incidence of updated EAD was 15% (164/1124). Multivariable analysis identified eight risk factors associated with EAD: % macrosteatosis, donor location, donor weight, nonheart beating donors, type of organ transplanted, recipient-associated hepatocellular carcinoma, severity of postreperfusion syndrome, and the amount of transfused fresh frozen plasma. In the presence of EAD, the incidence of post-transplant renal replacement therapy and dialysis dependence increases. There was a significant association of the presence of EAD with 6-month mortality (12% vs 3%) and 6-month graft failure (8% vs 1%). CONCLUSION: Higher AST/ALT level needed as cutoff in comparison with the old EAD definition.

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.

Thromboprophylaxis With Heparin During Orthotopic Liver Transplantation: Comparison of Hepcon HMS Plus and Anti-Xa Assays for Low-Range Heparin.

OBJECTIVES: The purpose of this study was to compare the agreement between two heparin assays, Hepcon HMS plus/Kaolin-ACT and Anti-Xa, and their predictive power in detecting circulating heparin levels post-reperfusion of the liver graft when compared with thromboelastogram (TEG) r time ratio in patients undergoing orthotopic liver transplantation (OLT). DESIGN: Prospective, observational cohort study design. SETTING: Single center, university hospital. PARTICIPANTS: Thirty-eight consecutive adults who had undergone liver transplant. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Paired arterial blood samples were collected before surgical incision, 5 minutes after administration of an average dose of 2,054±771 units of intravenous unfractionated heparin before caval cross-clamping, 5 minutes after portal reperfusion, 5 minutes after hepatic artery reperfusion, and 1 hour after hepatic artery reperfusion. The observations that heparin assay measurements were within the predetermined limits of agreement, strongly suggested the two heparin assays (Hepcon HMS plus and Anti-Xa assay) are interchangeable during prophylactic heparin dose therapy during OLT. Post-reperfusion, receiver operating characteristic curve analysis revealed high accuracy in measuring circulating heparin levels with both Anti-Xa and Hepcon HMS assays when compared with the TEG r time ratio assay. CONCLUSIONS: The point-of-care Hepcon HMS plus/Kaolin-ACT (activated clotting time) assay appeared to be a reliable alternative to the more expensive and laboratory-required Anti-Xa assay in monitoring the response to intravenous heparin in patients undergoing OLT.

Epsilon-Aminocaproic Acid Has No Association With Thromboembolic Complications, Renal Failure, or Mortality After Liver Transplantation.

OBJECTIVES: To examine the role of epsilon-aminocaproic acid (EACA) administered after reperfusion of the donor liver in the incidences of thromboembolic events and acute kidney injury within 30 days after orthotopic liver transplantation. One-year survival rates between the EACA-treated and EACA-nontreated groups also were examined. DESIGN: Retrospective, observational, cohort study design. SETTING: Single-center, university hospital. PARTICIPANTS: The study included 708 adult liver transplantations performed from 2008 to 2013. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: EACA administration was not associated with incidences of intracardiac thrombosis/pulmonary embolism (1.3%) or intraoperative death (0.6%). Logistic regression (n = 708) revealed 2 independent risk factors associated with myocardial ischemia (age and pre-transplant vasopressor use) and 8 risk factors associated with the need for post-transplant dialysis (age, female sex, redo orthotopic liver transplantation, preoperative sodium level, pre-transplant acute kidney injury or dialysis, platelet transfusion, and re-exploration within the first week after transplant); EACA was not identified as a risk factor for either outcome. One-year survival rates were similar between groups: 92% in EACA-treated group versus 93% in the EACA-nontreated group. CONCLUSIONS: The antifibrinolytic, EACA, was not associated with an increased incidence of thromboembolic complications or postoperative acute kidney injury, and it did not alter 1-year survival after liver transplantation.

Distal Peripheral Nerve Blocks in the Forearm as an Alternative to Proximal Brachial Plexus Blockade in Patients Undergoing Hand Surgery: A Prospective and Randomized Pilot Study.

PURPOSE: Limited data exist regarding the role of perineural blockade of the distal median, ulnar, and radial nerves as a primary anesthetic in patients undergoing hand surgery. We conducted a prospective and randomized pilot study to compare these techniques to brachial plexus blocks as a primary anesthetic in this patient population. METHODS: Sixty patients scheduled for hand surgery were randomized to receive either an ultrasound-guided supraclavicular, infraclavicular, or axillary nerve block (brachial plexus blocks) or ultrasound-guided median, ulnar, and radial nerve blocks performed at the level of the mid to proximal forearm (forearm blocks). The ability to undergo surgery without analgesic or local anesthetic supplementation was the primary outcome. Block procedure times, postanesthesia care unit length of stay, instances of nausea/vomiting, and need for narcotic administration were also assessed. RESULTS: The 2 groups were similar in terms of the need for conversion to general anesthesia or analgesic or local anesthetic supplementation, with only 1 patient in the forearm block group and 2 in the brachial plexus block group requiring local anesthetic supplementation or conversion to general anesthesia. Similar durations in surgical and tourniquet times were also observed. Both groups reported similarly low numerical rating scale pain scores as well as the need for postoperative analgesic administration (2 patients in the forearm block group and 1 in the brachial plexus block group reported numerical rating scale pain scores > 0 and required opioid administration in the postanesthesia care unit). Block procedure characteristics were similar between the 2 groups. CONCLUSIONS: Forearm blocks may be used as a primary anesthetic in patients undergoing hand surgery. Further research is warranted to determine the appropriateness of these techniques in patients undergoing surgery in the thumb or proximal to the hand. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic II.

Adverse cardiac events after orthotopic liver transplantation: a cross-sectional study in 389 consecutive patients.

Current American College of Cardiology/American Heart Association guidelines caution that preoperative noninvasive cardiac tests may have poor predictive value for detecting coronary artery disease in liver transplant candidates. The purpose of our study was to evaluate the role of clinical predictor variables for early and late cardiac morbidity and mortality and the predictive values of noninvasive cardiac tests for perioperative cardiac events in a high-risk liver transplant population. In all, 389 adult recipients were retrospectively analyzed for a median follow-up time of 3.4 years (range = 2.3-4.4 years). Overall survival was 83%. During the first year after transplantation, cardiovascular morbidity and mortality rates were 15.2% and 2.8%. In patients who survived the first year, cardiovascular morbidity and mortality rates were 3.9% and 2%, with cardiovascular etiology as the third leading cause of death. Dobutamine stress echocardiography (DSE) and single-photon emission computed tomography had respective sensitivities of 9% and 57%, specificities of 98% and 75%, positive predictive values of 33% and 28%, and negative predictive values of 89% and 91% for predicting early cardiac events. A rate blood pressure product less than 12,000 with DSE was associated with an increased risk for postoperative atrial fibrillation. Correspondence analysis identified a statistical association between nonalcoholic steatohepatitis/cryptogenic cirrhosis and postoperative myocardial ischemia. Logistic regression identified 3 risk factors for postoperative acute coronary syndrome: age, history of coronary artery disease, and pretransplant requirement for vasopressors. Multivariable analysis showed statistical associations of the Model for End-Stage Liver Disease score and the development of acute kidney injury as risk factors for overall cardiac-related mortality. These findings may help in identifying high-risk patients and may lead to the development of better cardiac tests.

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.

Vasodilator responses to acetylcholine are not mediated by the activation of soluble guanylate cyclase or TRPV4 channels in the rat.

The effects of 1H-[1,2,4]-oxadizaolo[4,3-]quinoxaline-1-one (ODQ), an inhibitor of the activation of soluble guanylate cyclase (sGC) on responses to NO donors acetylcholine (ACh) and bradykinin (BK) were investigated in the pulmonary and systemic vascular beds of the rat. In these studies the administration of ODQ in a dose of 5 mg/kg iv attenuated vasodilator responses to five different NO donors without inhibiting responses to ACh and BK in the systemic and pulmonary vascular beds of the rat. Vasodilator responses to ACh were not inhibited by l-NAME or the transient receptor vanilloid type 4 (TRPV4) antagonist GSK-2193874, which attenuated vasodilator responses to the TRPV4 agonist GSK-1016790A. ODQ did not inhibit vasodilator responses to agents reported to act in an NO-independent manner or to vasoconstrictor agents, and ODQ did not increase blood methemoglobin levels, suggesting that off target effects were minimal. These results show that ODQ in a dose that inhibited NO donor-mediated responses did not alter vasodilator responses to ACh in the pulmonary and systemic vascular beds and did not alter systemic vasodilator responses to BK. The present results indicate that decreases in pulmonary and systemic arterial pressures in response to ACh are not mediated by the activation of sGC or TRPV4 channels and that ODQ can be used to study the role of the activation of sGC in mediating vasodilator responses in the rat.

Intratracheal administration of cyclooxygenase-1-transduced adipose tissue-derived stem cells ameliorates monocrotaline-induced pulmonary hypertension in rats.

The effect of intratracheal administration of cyclooxygenase-1 (COX-1)-modified adipose stem cells (ASCs) on monocrotaline-induced pulmonary hypertension (MCT-PH) was investigated in the rat. The COX-1 gene was cloned from rat intestinal cells, fused with a hemagglutanin (HA) tag, and cloned into a lentiviral vector. The COX-1 lentiviral vector was shown to enhance COX-1 protein expression and inhibit proliferation of vascular smooth muscle cells without increasing apoptosis. Human ASCs transfected with the COX-1 lentiviral vector (ASCCOX-1) display enhanced COX-1 activity while exhibiting similar differentiation potential compared with untransduced (native) ASCs. PH was induced in rats with MCT, and the rats were subsequently treated with intratracheal injection of ASCCOX-1 or untransduced ASCs. The intratracheal administration of ASCCOX-1 3 × 10(6) cells on day 14 after MCT treatment significantly attenuated MCT-induced PH when hemodynamic values were measured on day 35 after MCT treatment whereas administration of untransduced ASCs had no significant effect. These results indicate that intratracheally administered ASCCOX-1 persisted for at least 21 days in the lung and attenuate MCT-induced PH and right ventricular hypertrophy. In addition, vasodilator responses to the nitric oxide donor sodium nitroprusside were not altered by the presence of ASCCOX-1 in the lung. These data emphasize the effectiveness of ASCCOX-1 in the treatment of experimentally induced PH.

Rate of Intraoperative Crystalloid Administration During Thoracic Surgery Is Causal in Reducing Postoperative Hospital Length of Stay.

Background: Studies in thoracic surgery have long raised concerns that intraoperative administration of intravenous fluids exacerbates or causes postoperative complications and hence advocate fluid restriction. Methods: This retrospective 3-year study investigated the role of intraoperative crystalloid administration rates on the duration of postoperative hospital length of stay (phLOS) and on the incidences of previously reported adverse events (AEs) in 222 consecutive patients following thoracic surgery. Results: Higher rates of intraoperative crystalloid administration were significantly associated with shorter phLOS (P=0.0006) and with less variance in phLOS. Dose-response curves showed progressive decreases in the postoperative incidences of surgical, cardiovascular, pulmonary, renal, other, and long-term AEs with higher intraoperative crystalloid administration rates. Conclusion: The rate of intravenous crystalloid administration during thoracic surgery was significantly associated with duration of and variance in phLOS, and dose-response curves showed progressive decreases in the incidences of AEs associated with this surgery. We cannot confirm that restrictive intraoperative crystalloid administration benefits patients undergoing thoracic surgery.

Analysis of responses to glyceryl trinitrate and sodium nitrite in the intact chest rat.

Responses to glyceryl trinitrate/nitroglycerin (GTN), S-nitrosoglutathione (GSNO), and sodium nitrite were compared in the intact chest rat. The iv injections of GTN, sodium nitrite, and GSNO produced dose-dependent decreases in pulmonary and systemic arterial pressures. In as much as cardiac output was not reduced, the decreases in pulmonary and systemic arterial pressures indicate that GTN, sodium nitrite, and GSNO have significant vasodilator activity in the pulmonary and systemic vascular beds in the rat. Responses to GTN were attenuated by cyanamide, but not allopurinol, whereas responses to nitrite formed by the metabolism of GTN were attenuated by allopurinol and cyanamide. The results with allopurinol and cyanamide suggest that only mitochondrial aldehyde dehydrogenase is involved in the bioactivation of GTN, sodium nitrite, and GSNO, whereas both pathways are involved in the bioactivation of nitrite anion in the intact rat. The comparison of vasodilator activity indicates that GSNO and GTN are more than 1000-fold more potent than sodium nitrite in decreasing pulmonary and systemic arterial pressures in the rat. Following administration of 1H-[1,2,4]-oxadizaolo[4,3-]quinoxaline-1-one (ODQ), responses to GTN were significantly attenuated, indicating that responses are mediated by the activation of soluble guanylyl cyclase. These data suggest that the reduction of nitrite to nitric oxide formed from the metabolism of GTN, cannot account for the vasodilator activity of GTN in the intact rat and that another mechanism; perhaps the formation of an S-NO, may mediate the vasodilator response to GTN in this species.

Effect of chronic sodium nitrite therapy on monocrotaline-induced pulmonary hypertension.

Pulmonary hypertension (PH) is a rare disorder that without treatment is progressive and often fatal within 3 years. The treatment of PH involves the use of a diverse group of drugs and lung transplantation. Although nitrite was once thought to be an inactive metabolite of endothelial-derived nitric oxide (NO), there is increasing evidence that nitrite may be useful in the treatment of PH, but the mechanism by which nitrite exerts its beneficial effect remains uncertain. The purpose of this study was to investigate the effect of chronic sodium nitrite treatment in a PH model in the rat. Following induction of PH with a single injection of monocrotaline, 60 mg; daily ip injections of sodium nitrite (3mg/kg) starting on day 14 and continuing for 21 days, resulted in a significantly lower pulmonary arterial pressure on day 35 when compared to values in untreated animals with monocrotaline-induced PH. In monocrotaline-treated rats, daily treatment with ip nitrite injections for 21 days decreased right ventricular mass and pathologic changes in small pulmonary arteries. Nitrite therapy did not change systemic arterial pressure or cardiac output when values were measured on day 35. The decreases in pulmonary arterial pressure in response to iv injections of sodium nitroprusside, sodium nitrite, and BAY 41-8543 were not different in rats with monocrotaline-induced pulmonary hypertension and rats with chronic nitrite therapy when compared to responses in animals in which pulmonary arterial pressure was increased with U46619. These findings are consistent with the hypothesis that the mechanisms that convert nitrite to vasoactive NO, activate soluble guanylyl cyclase and mediate the vasodilator response to NO or an NO derivative are not impaired. The present data are consistent with the results of a previous study in monocrotaline-induced PH in which systemic arterial pressure and cardiac output were not evaluated and are consistent with the hypothesis that nitrite is effective in the treatment of monocrotaline-induced PH in the rodent.

The Rho kinase inhibitor azaindole-1 has long-acting vasodilator activity in the pulmonary vascular bed of the intact chest rat.

Responses to a selective azaindole-based Rho kinase (ROCK) inhibitor (azaindole-1) were investigated in the rat. Intravenous injections of azaindole-1 (10-300 µg/kg), produced small decreases in pulmonary arterial pressure and larger decreases in systemic arterial pressure without changing cardiac output. Responses to azaindole-1 were slow in onset and long in duration. When baseline pulmonary vascular tone was increased with U46619 or L-NAME, the decreases in pulmonary arterial pressure in response to the ROCK inhibitor were increased. The ROCK inhibitor attenuated the increase in pulmonary arterial pressure in response to ventilatory hypoxia. Azaindole-1 decreased pulmonary and systemic arterial pressures in rats with monocrotaline-induced pulmonary hypertension. These results show that azaindole-1 has significant vasodilator activity in the pulmonary and systemic vascular beds and that responses are larger, slower in onset, and longer in duration when compared with the prototypical agent fasudil. Azaindole-1 reversed hypoxic pulmonary vasoconstriction and decreased pulmonary and systemic arterial pressures in a similar manner in rats with monocrotaline-induced pulmonary hypertension. These data suggest that ROCK is involved in regulating baseline tone in the pulmonary and systemic vascular beds, and that ROCK inhibition will promote vasodilation when tone is increased by diverse stimuli including treatment with monocrotaline.

Peroxynitrite has potent pulmonary vasodilator activity in the rat.

Peroxynitrite (PN) worsens pathological conditions associated with oxidative stress. However, beneficial effects have also been reported. PN has been shown to demonstrate vasodilator as well as vasoconstrictor properties that are dependent upon the experimental conditions and the vascular bed studied. PN-induced vascular smooth muscle relaxation may involve the formation of nitric oxide (NO) donors. The present results show that PN has significant vasodilator activity in the pulmonary and systemic vascular beds, and that responses to PN were not attenuated by L-penicillamine (L-PEN), a PN scavenger, whereas responses to sodium nitroprusside (SNP) were decreased. PN had a small inhibitory effect on decreases in arterial pressure in response to the NO donors diethylammonium (Z)-1-(N,N-diethylamino)diazen-1-ium-1,2-diolate (DEA/NO) and S-nitrosoglutathione (GSNO). PN partially reversed hypoxic pulmonary vasoconstriction. PN responses were attenuated by the soluble guanylate cyclase (sGC) inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and responses to PN and the PN precursor, 3-morpholinosydnonimine (SIN-1), were different. These data show that PN has potent pulmonary vasodilator activity in the rat, and provide evidence that a PN interaction with S-nitrosothiols is not the major mechanism mediating the response. These data suggest that responses to PN are mediated by the activation of sGC, and that PN has a small inhibitory effect on NO responses.

Influences observed on incidence and reporting of medication errors in anesthesia.

BACKGROUND: Medication errors are a common occurrence during the conduct of anesthesia (one in 133-450 [corrected] patients). Several factors contribute to medication errors in anesthesia, including experience of the anesthesia provider, severity of comorbidities, and type of procedure. The inexperience of anesthesia providers-in-training also leads to increased error rates. This prospective observational study repeats and extends previous work by Webster et al. and Llewellyn et al. examining the role of comorbidities, type of case, and level of provider experience on the incidence of medication errors. METHODS: After Institutional Review Board review and exemption from informed consent, medication error reporting forms were attached to every anesthetic record during a six-month period. All providers were asked to return the forms for every anesthetic, on a strictly voluntary and anonymous basis, and to record the occurrence of medication errors. If providers indicated that a medication error had occurred, additional details about the event were obtained anonymously. RESULTS: There were 8,777 (83%) responses obtained in a review of 10,574 case forms. A medication error was reported in 35 forms, with an additional 17 forms indicating a medication pre-error or near miss, resulting in 52 (0.49%) errors/pre-errors or a reported incidence of 1:203 anesthetics. Most case types were observed to have a statistically significant increase in reported medication errors. Reported errors by type of anesthesia provider were categorized into anesthesia provider-in-training group and the experienced provider group. The anesthesia provider-in-training group reported a twofold increase in the rate of errors, with the most frequently reported errors being incorrect dose and substitution. CONCLUSION: This study suggests that case type, American Society of Anesthesiologists' classification, and level of provider experience play a role on the rate of medication errors. The results of this study are in agreement with previously reported error rates.

Perioperative Efficiency of Sugammadex Following Laparoscopic Cholecystectomy in Clinical Practice.

Background: Studies have proposed that the routine use of the modified gamma-cyclodextrin, sugammadex, could provide perioperative time savings. However, these investigations have been limited to small group analyses. The purpose of this study was to test the effectiveness of sugammadex on perioperative times when compared to neostigmine under general clinical practice conditions following rocuronium-induced neuromuscular blockade for laparoscopic cholecystectomy. Methods: Following institutional review board approval, data from 1,611 consecutive surgical records for laparoscopic cholecystectomy were reviewed. Patient characteristics, type of primary neuromuscular blocking reversal agent, operating room (OR) discharge times, and postanesthesia care unit (PACU) recovery times were the measures of interest. Equivalence testing was used to determine the between-group differences of the reversal agents in the two perioperative time periods of interest. Results: OR discharge times averaged 10.9 (95% CI, 10-11.8) minutes for patients administered sugammadex and 8.9 (95% CI, 8.2-9.7) minutes for patients administered neostigmine. PACU recovery times averaged 77.6 (95% CI, 74.1-81.1) minutes for sugammadex and 68.6 (95% CI, 65.9-71.3) minutes for neostigmine. Equivalence testing demonstrated no improvement in the two perioperative times with sugammadex. Conclusion: These results suggest no perioperative time savings with sugammadex when compared to neostigmine following laparoscopic cholecystectomy under general clinical practice conditions.