Image intensification - A solution for difficult guidewire insertion for central venous access: A case report.

PRESENTATION OF CASE: A 56-year old male presented for an elective redo-sternotomy, aortic valve replacement, tricuspid valve annuloplasty, and coronary artery bypass grafting. During central vascular access using a standard Seldinger technique, resistance to two spring-wire guide wires was encountered when the wires were advanced through the patient's internal jugular vein. Ultrasound provided limited views of the anatomical path of the guidewires and was unable to provide visualisation of the level or cause of obstruction. We describe the application of continuous image intensification to successfully identify the anatomical location and safe circumnavigation of guidewire obstruction during the insertion of a central venous and pulmonary artery catheter for cardiac surgery. DISCUSSION: The use of x-ray image intensification enabled the immediate identification of the cause of obstruction, minimising further attempts at guidewire insertion and subsequent complications. The direct real-time visualisation allowed for manoeuvres such as wire manipulation, rotation and advancement to be safely performed. CONCLUSION: Image intensification may decrease malposition rates and mechanical complications associated with difficult central venous catheterisation. Further research comparing the safety and efficiency of ultrasound-guided and fluoroscopy-guided CVC insertion should be contemplated.

Video Fluoroscopy for Positioning of Pulmonary Artery Catheters in Patients Undergoing Cardiac Surgery.

OBJECTIVES: To determine whether video fluoroscopy combined with traditional pressure waveform analyses facilitates optimal pulmonary artery catheter (PAC) flotation and final positioning compared with the traditional pressure waveform flotation technique alone. DESIGN: Prospective, single-center, randomized, controlled trial. SETTING: Single-center university teaching hospital. PARTICIPANTS: The study included 50 cardiac surgery patients at higher risk for PAC complications. INTERVENTIONS: Use of video fluoroscopy to facilitate optimal PAC flotation and positioning. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the time taken to float and position the PAC balloon in the pulmonary artery as confirmed by transesophageal echocardiography. Secondary outcomes included number of attempts at flotation, ventricular rhythm disturbances, and catheter malposition. Patients were evenly matched in baseline demographics, New York Heart Association symptoms of heart failure, severity of left and right ventricular dysfunction, end-diastolic pressures and dimensions, severity of tricuspid valvular disease, and atrial and pulmonary artery pressures. Mean (SD) time to float the PAC was significantly shorter in the video fluoroscopy group than in the usual care group: 73 seconds (SD, 65.1) versus 176 seconds (SD, 180.6), respectively; p = 0.014. The median (interquartile range [IQR]) number of attempts to successful flotation was fewer in the video fluoroscopy group than in the usual care group: 1 (IQR 1:2) attempt versus 2 (IQR 1:4) attempts, respectively; p = 0.007. The composite complication rate (malposition and arrhythmias) was lower in the video fluoroscopy group than in the usual care group (16% v 52%, respectively; p = 0.01). CONCLUSIONS: In cardiac surgery patients at higher risk for PAC complications, video fluoroscopy facilitated faster and safer catheter flotation and positioning compared with the traditional pressure waveform flotation technique.

Massive air embolism from continuous venovenous haemofiltration causing electromechanical dissociation in a cardiac surgical patient.

Venous air embolism is a rare but life-threatening complication of continuous venovenous haemofiltration. We report a case of massive venous air embolism associated with haemofiltration in a 75-year-old man after complicated cardiac surgery. Haemofiltration circuitry and air detector alarms are not infallible and air embolism should be considered in patients receiving such therapy who develop cardiopulmonary instability. We discuss our early intervention, which focused on restoration of the circulation, prevention of further air entry, retrieval of air and supportive care. The use of transoesophageal echocardiography for diagnosis of air embolism and to aid the insertion of a pulmonary artery catheter for air aspiration was essential for management.

Decreased catecholamine degradation associates with shock and kidney injury after cardiac surgery.

Enzymatic pathways involving catechol-O-methyltransferase (COMT) catabolize circulating catecholamines. A G-to-A polymorphism in the fourth exon of the COMT gene results in a valine-to-methionine amino acid substitution at codon 158, which leads to thermolability and low ("L"), as opposed to high ("H"), enzymatic activity. We enrolled 260 patients postbypass surgery to test the hypothesis that COMT gene variants impair circulating catecholamine metabolism, predisposing to shock and acute kidney injury (AKI) after cardiac surgery. In accordance with the Hardy-Weinberg equilibrium, we identified 64 (24.6%) homozygous (LL), 123 (47.3%) heterozygous (HL), and 73 (28.1%) homozygous (HH) patients. Postoperative catecholamines were higher in homozygous LL patients compared with heterozygous HL and homozygous HH patients (P < 0.01). During their intensive care stay, LL patients had both a significantly greater frequency of vasodilatory shock (LL: 69%, HL: 57%, HH: 47%; P = 0.033) and a significantly longer median duration of shock (LL: 18.5 h, HL: 14.0 h, HH: 11.0 h; P = 0.013). LL patients also had a greater frequency of AKI (LL: 31%, HL: 19.5%, HH: 13.7%; P = 0.038) and their AKI was more severe as defined by a need for renal replacement therapy (LL: 7.8%, HL: 2.4%, HH: 0%; P = 0.026). The LL genotype associated with intensive care and hospital length of stay (P < 0.001 and P = 0.002, respectively), and we observed a trend for higher mortality. Cross-validation analysis revealed a similar graded relationship of adverse outcomes by genotype. In summary, this study identifies COMT LL homozygosity as an independent risk factor for shock, AKI, and hospital stay after cardiac surgery. (ClinicalTrials.gov number, NCT00334009).

Sodium bicarbonate to prevent increases in serum creatinine after cardiac surgery: a pilot double-blind, randomized controlled trial.

OBJECTIVE: To test whether perioperative sodium bicarbonate infusion can attenuate postoperative increases in serum creatinine in cardiac surgical patients. DESIGN: Double-blind, randomized controlled trial. SETTING: Operating rooms and intensive care unit at a tertiary hospital. PATIENTS: Cohort of 100 cardiac surgical patients at increased risk of postoperative acute renal dysfunction. INTERVENTION: Patients were randomized to either 24 hrs of intravenous infusion of sodium bicarbonate (4 mmol/kg) or sodium chloride (4 mmol/kg). MEASUREMENTS AND MAIN RESULTS: The primary outcome measure was the proportion of patients developing acute renal dysfunction defined as a postoperative increase in plasma creatinine concentration >25% of baseline within the first five postoperative days. Secondary outcomes included changes in plasma creatinine, plasma urea, urinary neutrophil gelatinase-associated lipocalin, and urinary neutrophil gelatinase-associated lipocalin/urinary creatinine ratio. Patients were well balanced for baseline characteristics. Sodium bicarbonate infusion increased plasma bicarbonate concentration (p < 0.001), base excess (p < 0.001), plasma pH (p < 0.001), and urine pH (p < 0.001). Fewer patients in the sodium bicarbonate group (16 of 50) developed a postoperative increase in serum creatinine compared with control (26 of 50) (odds ratio 0.43 [95% confidence interval 0.19-0.98]), (p = 0.043). The increase in plasma creatinine, plasma urea, urinary neutrophil gelatinase-associated lipocalin, and urinary neutrophil gelatinase-associated lipocalin/urinary creatinine ratio was less in patients receiving sodium bicarbonate, (p = 0.014; p = 0.047; p = 0.009; p = 0.004). There were no significant side effects. CONCLUSIONS: Sodium bicarbonate loading and continuous infusion was associated with a lower incidence of acute renal dysfunction in cardiac surgical patients undergoing cardiopulmonary bypass. The findings of this pilot study justify further investigation. (ClinicalTrials.gov, NCT00334191).

A change of heart: acute cardiac dextroversion with cardiogenic shock after partial lung resection.

Cardiac herniation and torsion are well described after intrapericardial pneumonectomy, but their occurrence after partial lung resection has been rarely discussed. This unusual case of acute right-sided cardiac dextroversion with torsion occurred in a 30-year-old man after radical right lower lobectomy, pericardial resection and a left lower-lobe wedge resection for locally recurrent and metastatic synovial sarcoma. We describe the management of this unusual cause of cardiogenic shock and review the current literature. Cardiac herniation and torsion are an uncommon cause of cardiogenic shock after lung resection and, if diagnosed late, are associated with significant mortality.

Phase II, randomized, controlled trial of high-dose N-acetylcysteine in high-risk cardiac surgery patients.

OBJECTIVE: To assess the effect of high-dose N-acetylcysteine on renal function in cardiac surgery patients at higher risk of postoperative renal failure. DESIGN: Multiblind, placebo-controlled, randomized, phase II clinical trial. SETTING: Operating rooms and intensive care units of two tertiary referral hospitals. PATIENTS: A total of 60 cardiac surgery patients at higher risk of postoperative renal failure. INTERVENTIONS: Patients were allocated to either 24 hrs of high-dose N-acetylcysteine infusion (300 mg/kg body weight in 5% glucose, 1.7 L) or placebo (5% glucose, 1.7 L). MEASUREMENTS AND MAIN RESULTS: The primary outcome measure was the absolute change in serum creatinine from baseline to peak value within the first five postoperative days. Secondary outcomes included the relative change in serum creatinine, peak serum creatinine level, serum cystatin C, and in urinary output. Further outcomes were needed for renal replacement therapy, length of ventilation, and length of stay in the intensive care unit and hospital. Randomization was successful and patients were well balanced for preoperative and intraoperative characteristics. There was no significant attenuation in the increase in serum creatinine from baseline to peak when comparing N-acetylcysteine with placebo (64.5 +/- 91.2 and 38.0 +/- 42.4 mumol/L, respectively; p = .15). Also, there was no attenuation in the increase in serum cystatin C from baseline to peak for N-acetylcysteine compared with placebo (0.45 +/- 0.43 and 0.30 +/- 0.33 mg/L, respectively; p = .40). Likewise, there was no evidence for differences in any other clinical outcome. CONCLUSIONS: In this phase II, randomized, controlled trial, high-dose N-acetylcysteine was no more effective than placebo in attenuating cardiopulmonary bypass-related acute renal failure in high-risk cardiac surgery patients.

Selecting a vasopressor drug for vasoplegic shock after adult cardiac surgery: a systematic literature review.

The choice of vasopressors to treat vasodilatory shock after cardiac surgery is a matter of controversy. We have systematically reviewed the literature and found that the data are insufficient to guide choice of agent. However, we found sufficient evidence that when a target blood pressure can not be achieved with a single agent, addition of another is more likely to help achieve the blood pressure target. We also found that there is no evidence that vasopressors induce organ ischemia. Finally, the lack of high quality data indicate that large multicenter trials are needed in this field.

Bench-to-bedside review: Inotropic drug therapy after adult cardiac surgery -- a systematic literature review.

Many adult patients require temporary inotropic support after cardiac surgery. We reviewed the literature systematically to establish, present and classify the evidence regarding choice of inotropic drugs. The available evidence, while limited in quality and scope, supports the following observations; although all beta-agonists can increase cardiac output, the best studied beta-agonist and the one with the most favourable side-effect profile appears to be dobutamine. Dobutamine and phosphodiesterase inhibitors (PDIs) are efficacious inotropic drugs for management of the low cardiac output syndrome. Dobutamine is associated with a greater incidence of tachycardia and tachyarrhythmias, whereas PDIs often require the administration of vasoconstrictors. Other catecholamines have no clear advantages over dobutamine. PDIs increase the likelihood of successful weaning from cardiopulmonary bypass as compared with placebo. There is insufficient evidence that inotropic drugs should be selected for their effects on regional perfusion. PDIs also increase flow through arterial grafts, reduce mean pulmonary artery pressure and improve right heart performance in pulmonary hypertension. Insufficient data exist to allow selection of a specific inotropic agent in preference over another in adult cardiac surgery patients. Multicentre randomized controlled trials focusing on clinical rather than physiological outcomes are needed.

Prospective controlled trial of effect of medical emergency team on postoperative morbidity and mortality rates.

OBJECTIVE: To determine whether the introduction of an intensive care unit-based medical emergency team, responding to hospital-wide preset criteria of physiologic instability, would decrease the rate of predefined adverse outcomes in patients having major surgery. DESIGN: Prospective, controlled before-and-after trial. SETTING: University-affiliated hospital. PATIENTS: Consecutive patients admitted to hospital for major surgery during a 4-month control phase and during a 4-month intervention phase. INTERVENTIONS: Introduction of a hospital-wide intensive care unit-based medical emergency team to evaluate and treat in-patients deemed at risk of developing an adverse outcome by nursing, paramedical, and/or medical staff. MEASUREMENTS AND MAIN RESULTS: We measured incidence of serious adverse events, mortality after major surgery, and mean duration of hospital stay. There were 1,369 operations in 1,116 patients during the control period and 1,313 in 1,067 patients during the medical emergency team intervention period. In the control period, there were 336 adverse outcomes in 190 patients (301 outcomes/1,000 surgical admissions), which decreased to 136 in 105 patients (127 outcomes/1,000 surgical admissions) during the intervention period (relative risk reduction, 57.8%; p <.0001). These changes were due to significant decreases in the number of cases of respiratory failure (relative risk reduction, 79.1%; p <.0001), stroke (relative risk reduction, 78.2%; p =.0026), severe sepsis (relative risk reduction, 74.3%; p =.0044), and acute renal failure requiring renal replacement therapy (relative risk reduction, 88.5%; p <.0001). Emergency intensive care unit admissions were also reduced (relative risk reduction, 44.4%; p =.001). The introduction of the medical emergency team was also associated with a significant decrease in the number of postoperative deaths (relative risk reduction, 36.6%; p =.0178). Duration of hospital stay after major surgery decreased from a mean of 23.8 days to 19.8 days (p =.0092). CONCLUSIONS: The introduction of an intensive care unit-based medical emergency team in a teaching hospital was associated with a reduced incidence of postoperative adverse outcomes, postoperative mortality rate, and mean duration of hospital stay.

A prospective before-and-after trial of a medical emergency team.

OBJECTIVE: To determine the effect on cardiac arrests and overall hospital mortality of an intensive care-based medical emergency team. DESIGN AND SETTING: Prospective before-and-after trial in a tertiary referral hospital. PATIENTS: Consecutive patients admitted to hospital during a 4-month "before" period (May-August 1999) (n = 21 090) and a 4-month intervention period (November 2000 -February 2001) (n = 20 921). MAIN OUTCOME MEASURES: Number of cardiac arrests, number of patients dying after cardiac arrest, number of postcardiac-arrest bed-days and overall number of in-hospital deaths. RESULTS: There were 63 cardiac arrests in the "before" period and 22 in the intervention period (relative risk reduction, RRR: 65%; P < 0.001). Thirty-seven deaths were attributed to cardiac arrests in the "before" period and 16 in the intervention period (RRR: 56%; P = 0.005). Survivors of cardiac arrest in the "before" period required 163 ICU bed-days versus 33 in the intervention period (RRR: 80%; P < 0.001), and 1353 hospital bed-days versus 159 in the intervention period (RRR: 88%; P < 0.001). There were 302 deaths in the "before" period and 222 in the intervention period (RRR: 26%; P = 0.004). CONCLUSIONS: The incidence of in-hospital cardiac arrest and death following cardiac arrest, bed occupancy related to cardiac arrest, and overall in-hospital mortality decreased after introducing an intensive care-based medical emergency team.

On-pump coronary artery surgery versus off-pump exclusive arterial coronary grafting: a matched cohort comparison.

BACKGROUND: It is unknown whether coronary artery bypass grafting without cardiopulmonary bypass and with exclusive use of arterial grafts (arterial off-pump CABG) offers any significant short-term advantages over standard CABG with cardiopulmonary bypass. Accordingly, we performed a comparison of the short-term outcomes of arterial off-pump and standard CABG patients matched for preoperative risk and number of grafts. METHODS: We studied 90 consecutive arterial off-pump CABG patients during a 2-year period, obtained demographic and clinical features and surgical characteristics, and calculated their predicted surgical risk (EuroSCORE). Using a database of 750 contemporaneous patients treated with standard CABG, we created a matched cohort of 90 patients using an iterative process prioritizing number of grafts, target vessels, EuroSCORE, age, and sex. We compared the two groups for baseline features and short-term clinical outcomes. RESULTS: There were no differences in age (65.9 versus 64.7 years), sex, EuroSCORE (3.3 versus 3. 6), number of grafts (2.1 versus 2.1), and preoperative left ventricular function. Arterial off-pump CABG, however, was associated with decreased duration of operation (213 versus 252 minutes; p < 0.0013), decreased peak postoperative troponin I levels (mean, 10.8 versus 29.1 ng/mL; p < 0.0001), decreased peak norepinephrine dose (2.3 versus 4.1 microg/ min; p < 0.0082), and decreased likelihood of receiving red blood cell transfusion (17.8% versus 40%; p = 0.0016). There were no differences in duration of intensive care unit or hospital stay, incidence of atrial fibrillation, or other clinical complications. There was one death in each group. CONCLUSIONS: After matching for number of grafts and other important preoperative risk markers, arterial off-pump CABG still decreases the need for red blood cell transfusion and offers other moderate clinical advantages compared with standard on-pump CABG.