Dysnatremia on intensive care unit admission is a stronger risk factor when associated with organ dysfunction.

AIM: Dysnatremia present at the time of intensive care unit (ICU) admission is associated with mortality. In this study, we investigated the epidemiology of dysnatremia present on ICU admission and the impact of organ dysfunction on the association between dysnatremia and mortality. We hypothesized that dysnatremia comorbid with organ dysfunction is associated with higher risk of mortality. METHODS: This retrospective study was conducted on all patients admitted to the International Hospital General ICU in Istanbul over a period of 6 years (2006-2011). Patients were classified, according to the most abnormal serum sodium values measured within 24 hours after ICU admission, into 7 groups as follows: normonatremia (135≤Na≤145 mmol/L), borderline hyponatremia (130≤Na<135 mmol/L), mild hyponatremia (125≤Na<130 mmol/L), severe hyponatremia (Na <125 mmol/L), borderline hypernatremia (145155 mmol/L). RESULTS: The total admitting patient were 1657. A total of 1060 patients' data were analyzed in this study. Sodium levels were normal in 637 (60.1%), hyponatremic in 367 (34.6%) and hypernatremic in 56 (5.3%) patients. Multivariate analysis showed that only SAPS II was associated with increased mortality (OR, 1.05 [95% confidence interval, 1.02-1.09]). The odds ratio (95% CI) of dysnatremia (Na <125 mmol/L and >150 mmol/L) for mortality was 4.37 (2.29-8.36) in patients with organ dysfunction (number of dysfunctional organs ≥1) (P<0.001). CONCLUSION: Below 125 and above 150 mmol/L sodium levels at ICU admission are risk factors for higher mortality rates in patients with comorbid organ dysfunction. The effect of dysnatremia on mortality is observed when organ dysfunction is present.

No additive effects of inhaled iloprost and prone positioning on pulmonary hypertension and oxygenation in acute respiratory distress syndrome.

BACKGROUND: In acute respiratory distress syndrome (ARDS), pulmonary hypertension is associated with a poor prognosis. Prone position is effective to improve oxygenation whereas inhaled iloprost can treat pulmonary hypertension. However, combination of these interventions has not been examined before. The hypothesis was that this combination had additive effects on oxygenation and pulmonary hemodynamics as compared with each intervention alone. METHODS: In a prospective, randomized cross-over study, ten pigs were anesthetized, intubated and ventilated with volume controlled ventilation. Carotid, jugular venous and pulmonary artery catheters were inserted. ARDS was induced with oleic acid (0.20 mL/kg). Measurements were repeated in randomized different sequences of prone or supine positions with or without iloprost inhalation (220 ng/kg/min) (four combinations). Systemic and pulmonary arterial pressures; arterial and mixed venous blood gases; and Qs/Qt and the resistances were recorded. RESULTS: Iloprost decreased pulmonary artery pressures (for MPAP: P=0.034) in both supine (37±10 vs. 31±8 mmHg; P<0.05) and prone positions (38±9 vs. 29±8 mmHg; P<0.05); but did not obtain a significant improvement in oxygenation in both positions. Prone position improved the oxygenation (p<0.0001) compared to supine position in both with (361±140 vs. 183±158 mmHg, P<0.05) or without iloprost application (331±112 vs. 167±117 mmHg, P<0.05); but did not achieve a significant decrease in MPAP. CONCLUSION: Although iloprost reduced pulmonary arterial pressures, and prone positioning improved oxygenation; there are no additive effects of the combination of both interventions on both parameters. To treat both pulmonary hypertension and hypoxemia, application of iloprost in prone position is suggested.

Effects of three different dose regimens of magnesium on propofol requirements, haemodynamic variables and postoperative pain relief in gynaecological surgery.

BACKGROUND: In this double-blind, randomized, placebo-controlled study we compared the effects of three different dose regimens of magnesium on intraoperative propofol and atracurium requirements, and postoperative morphine consumption in patients undergoing gynaecological surgery. METHODS: Eighty women were allocated to four equal groups. The control group received normal saline; magnesium groups received 40 mg kg(-1) of magnesium before induction of anaesthesia, followed by i.v. infusion of normal saline, magnesium 10 mg kg(-1) h(-1) or magnesium 20 mg kg(-1) h(-1) for the next 4 h. Propofol infusion was targeted to keep bispectral index values between 45 and 55. Postoperative analgesia was achieved using PCA with morphine. RESULTS: Magnesium groups required significantly less propofol [mean (sd) 121.5 (13.3), 102.2 (8.0) and 101.3 (9.7) microg kg(-1) min(-1) respectively] than the control group (140.7 (16.5) microg kg(-1) min(-1)). Atracurium use was significantly higher in the control group than magnesium groups [0.4 (0.06) vs 0.34 (0.06), 0.35 (0.04), 0.34 (0.06) mg kg(-1) h(-1) respectively]. Morphine consumption was significantly higher in control group than magnesium groups on the first postoperative day [0.88 (0.14) vs 0.73 (0.17), 0.59 (0.23), 0.53 (0.21) mg kg(-1) respectively]. The heart rate was lower in magnesium groups and 20 mg kg(-1) h(-1) infusion group demonstrated the lowest values. CONCLUSION: Magnesium 40 mg kg(-1) bolus followed by 10 mg kg(-1) h(-1) infusion leads to significant reductions in intraoperative propofol, atracurium and postoperative morphine consumption. Increasing magnesium dosage did not offer any advantages, but induced haemodynamic consequences.

Reliability of procalcitonin as a severity marker in critically ill patients with inflammatory response.

Procalcitonin (PCT) is increasingly recognised as an important diagnostic parameter in clinical evaluation of the critically ill. This prospective study was designed to investigate PCT as a diagnostic marker of infection in critically ill patients with sepsis. Eighty-five adult ICU patients were studied. Four groups were defined on the basis of clinical, laboratory and bacteriologic findings as systemic inflammatory response syndrome (SIRS) (n = 10), sepsis (n = 16), severe sepsis (n = 18) and septic shock (n = 41). Data were collected including C-reactive protein (CRP), PCT levels and Sequential Organ Failure Assessment and Acute Physiology and Chronic Health Evaluation II scores on each ICU day. PCT levels were significantly higher in patients with severe sepsis and septic shock (19.25 +/- 43.08 and 37.15 +/- 61.39 ng/ml) than patients with SIRS (0.73 +/- 1.37 ng/ml) (P < 0.05 for each comparison). As compared with SIRS patients, plasma PCT levels were significantly higher in infected patients (21.9 +/- 47.8 ng/ml), regardless of the degree of sepsis (P < 0.001). PCT showed a higher sensitivity (73% versus 35%) and specificity (83% versus 42%) compared to CRP in identifying infection as a cause of the inflammatory response. Best cut-off levels were 1.31 ng/ml for PCT and 13.9 mg/dl for CRP. We suggest that PCT is a more reliable marker than CRP in defining infection as a cause of systemic inflammatory response.

Evaluation of effects of magnesium sulphate in reducing intraoperative anaesthetic requirements.

BACKGROUND: The present randomized, placebo-controlled, double-blind study was designed to assess the effect of peroperatively administered i.v. magnesium sulphate on anaesthetic and analgesic requirements during total i.v. anaesthesia. METHODS: Eighty-one patients (36 women, 45 men) undergoing elective spinal surgery were included in one of two parallel groups. The magnesium group received magnesium sulphate 30 mg kg(-1) as a bolus before induction of anaesthesia and 10 mg kg(-1) h(-1) by continuous i.v. infusion during the operation period. The same volume of isotonic solution was administered to the control group. Anaesthesia was maintained with propofol (administered according to the bispectral index) and remifentanil (adjusted according to heart rate and arterial blood pressure) infusions. RESULTS: A significant reduction in hourly propofol consumption was observed with magnesium administration. For example, the mean infusion rate of propofol in the second hour of the operation was 7.09 mg kg(-1) h(-1) in the control group vs 4.35 mg kg(-1) h(-1) in the magnesium group (P<0.001). The magnesium group required significantly less remifentanil (P<0.001) and vecuronium (P<0.001). No side-effects were observed with magnesium administration. CONCLUSION: The administration of magnesium led to a significant reduction in the requirements for anaesthetic drugs during total i.v. anaesthesia with propofol, remifentanil and vecuronium.

Time required for partial pressure of arterial oxygen equilibration during mechanical ventilation after a step change in fractional inspired oxygen concentration.

OBJECTIVE: To determine the time required for the partial pressure of arterial oxygen (PaO2) to reach equilibrium after a 0.20 increment or decrement in fractional inspired oxygen concentration (FIO2) during mechanical ventilation. SETTING: A multi-disciplinary ICU in a university hospital. PATIENTS AND METHODS: Twenty-five adult, non-COPD patients with stable blood gas values (PaO2/FIO2 > or = 180 on the day of the study) on pressure-controlled ventilation (PCV). Following a baseline PaO2 (PaO2b) measurement at FIO2 = 0.35, the FIO2 was increased to 0.55 for 30 min and then decreased to 0.35 without any other change in ventilatory parameters. Sequential blood gas measurements were performed at 3, 5, 7, 9, 11, 15, 20, 25 and 30 min in both periods. The PaO2 values measured at the 30th min after a step change in FIO2 (FIO2 = 0.55, PaO2[55] and FIO2 = 0.35, PaO2[35]) were accepted as representative of the equilibrium values for PaO2. Each patient's rise and fall in PaO2 over time, PaO2(t), were fitted to the following respective exponential equations: PaO2b + (PaO2[55]-PaO2b)(1-e-kt) and PaO2[55] + (PaO2[35]-PaO2[55])(e-kt) where "t" refers to time, PaO2[55] and PaO2[35] are the final PaO2 values obtained at a new FIO2 of 0.55 and 0.35, after a 0.20 increment and decrement in FIO2, respectively. Time constant "k" was determined by a non-linear fitting curve and 90% oxygenation times were defined as the time required to reach 90% of the final equilibrated PaO2 calculated by using the non-linear fitting curves. RESULTS: Time constant values for the rise and fall periods were 1.01 +/- 0.71 min-1, 0.69 +/- 0.42 min-1, respectively, and 90% oxygenation times for rises and falls in PaO2 periods were 4.2 +/- 4.1 min-1 and 5.5 +/- 4.8 min-1, respectively. There was no significant difference between the rise and fall periods for the two parameters (p > 0.05). CONCLUSION: We conclude that in stable patients ventilated with PCV, after a step change in FIO2 of 0.20, 5-10 min will be adequate for obtaining a blood gas sample to measure a PaO2 that will be representative of the equilibrium PaO2 value.

Ketamine infusion versus isoflurane for the maintenance of anesthesia in the prebypass period in children with tetralogy of Fallot.

OBJECTIVE: To evaluate the use of ketamine in comparison with isoflurane in the maintenance of anesthesia in children with tetralogy of Fallot. DESIGN: Prospective, randomized study. SETTING: University hospital. PARTICIPANTS: Fifty children scheduled for correction of tetralogy of Fallot. INTERVENTIONS: After intubation, patients were assigned randomly to receive 2 different anesthesia maintenance regimens: group I, isoflurane, 0 to 1% plus fentanyl, 0.1 microg/kg/min; group II, ketamine, 0 to 5 mg/kg/h, plus fentanyl, 0.1 microg/kg/min. Isoflurane concentration and ketamine infusion rate were adjusted to maintain arterial pressure within 25% of baseline. Hemodynamic and respiratory parameters were recorded at the end of 4 intervals: T0, before induction of anesthesia; T1, induction to 10 minutes postintubation; T2, 10 minutes postintubation to poststernotomy; and T3, poststernotomy to completion of catheterizations. MEASUREMENTS AND MAIN RESULTS: In comparing group I with group II, significant differences were observed in mean arterial pressure (p < 0.0001), heart rate (p < 0.01), arterial oxygen saturation (p < 0.0001), arterial oxygen tension (p < 0.001), arterial carbon dioxide tension (p < 0.001), arterial pH (p < 0.0001), base excess (p < 0.05), and arterial to end-tidal carbon dioxide tension difference (p < 0.01) at T3. CONCLUSION: The use of ketamine anesthesia is recommended as an alternative maintenance regimen in children undergoing definitive correction of tetralogy of Fallot.

Risk factors for early-onset, ventilator-associated pneumonia in critical care patients: selected multiresistant versus nonresistant bacteria.

BACKGROUND: Ventilator-associated pneumonia is the leading nosocomial infection in critically ill patients. The frequency of ventilator-associated pneumonia caused by multidrug-resistant bacteria has increased in recent years, and these pathogens cause most of the deaths attributable to pneumonia. The authors, therefore, evaluated factors associated with selected multidrug-resistant ventilator-associated pneumonia in critical care patients. METHODS: The authors prospectively recorded potential risk factors at the time of intensive care unit admission. An endotracheal aspirate was obtained in all patients who met clinical criteria for pneumonia. Patients were considered to have ventilator-associated pneumonia only when they met the clinical criteria and aspirate culture was positive for bacteria 48 h or more after initiation of mechanical ventilation. Pediatric patients were excluded. Adult patients with ventilator-associated pneumonia were first grouped as "early-onset" (< 5 days) and "late-onset," determined by episodes of ventilator-associated pneumonia, and then, assigned to four groups based on the bacteria cultured from their tracheal aspirates: Pseudomonas aeruginosa, Acinetobacter baumanii, methicillin-resistant staphylococci, and all others. The first three bacteria were considered to be multidrug resistant, whereas the others were considered to be antibiotic susceptible. Potential risk factors were evaluated with use of univariate statistics and multivariate regression. RESULTS: Among 486 consecutive patients admitted during the study, 260 adults underwent mechanical ventilation for more than 48 h. Eighty-one patients (31%) experienced 99 episodes of ventilator-associated pneumonia, including Pseudomonas(33 episodes), methicillin-resistant staphylococci (17 episodes), Acinetobacter(9 episodes), and nonresistant bacteria (40 episodes). Sixty-six of these episodes were early onset and 33 episodes were late onset. Logistic regression analysis identified three factors significantly associated with early-onset ventilator-associated pneumonia caused by any one of the multidrug-resistant bacterial strains: emergency intubation (odds ratio, 6.4; 95% confidence interval, 2.0-20.2), aspiration (odds ratio, 12.7; 95% confidence interval, 2.4-64.6), and Glasgow coma score of 9 or less (odds ratio, 3.9; 95% confidence interval, 1.3-11.3). A. baumanii-related pneumonia cases were found to be significantly associated with two of these factors: aspiration (odds ratio, 14.2; 95% confidence interval, 1.5-133.8) and Glasgow coma score (odds ratio, 6.0; 95% confidence interval, 1.1-32.6). CONCLUSIONS: The authors recommend that patients undergoing emergency intubation or aspiration or who have a Glasgow coma score of 9 or less be monitored especially closely for early-onset multidrug-resistant pneumonia. The occurrence of aspiration and a Glasgow coma score of 9 or less are especially associated with pneumonia caused by A. baumanii.

Comparison of the effects of sodium nitroprusside and isoflurane during rewarming on cardiopulmonary bypass.

OBJECTIVES: Afterdrop in core temperatures after discontinuation of cardiopulmonary bypass (CPB) is reported to be a sign of inadequate total body rewarming on CPB. The purpose of this study was to compare the effects of three different drug regimens on hemodynamic stability and the uniformity of rewarming during the rewarming period of CPB. DESIGN: This prospective randomized study was performed in the Anesthesiology Department of the University of Istanbul. PARTICIPANTS: Sixty-six patients undergoing uncomplicated valve replacement and aortocoronary bypass grafting surgery were studied. INTERVENTIONS: Anesthesia was maintained with isoflurane and fentanyl infusion during the prebypass and the postbypass periods. Patients were allocated into three groups by the initiation of CPB. Group 1 (n = 22): fentanyl infusion + diazepam + sodium nitroprusside (SNP) in the rewarming period), group 2 (n = 22): fentanyl infusion + isoflurane, group 3, control (n = 22): fentanyl infusion + diazepam. Rectal, esophageal, and forearm temperatures were monitored throughout the study. MEASUREMENTS AND MAIN RESULTS: None of the durational and temperature data showed significant differences between groups 1 and 2. In the control group, afterdrop in esophageal temperature was significantly higher than groups 1 and 2 (group 1: -1.4 +/- 0.9 degrees C, group 2: -1.44 +/- 0.8 degrees C, group 3: -2.1 +/- 0.65 degrees C). In group 1, the number of patients whose mean arterial pressure (MAP) decreased below 45 mmHg was significantly higher than group 2 (p = 0.002). Mean SNP infusion rate and mean isoflurane concentration during the rewarming period were calculated as 1.55 +/- 0.8 micrograms/kg/min and 0.775 +/- 0.27%, respectively. CONCLUSIONS: Isoflurane produced more stable hemodynamic conditions than SNP during the rewarming period, improved the uniformity of rewarming, and permitted earlier extubation in the intensive care unit (ICU). It is concluded that isoflurane alone is capable of fulfilling the anesthesia needs during hypothermia and the rewarming period of CPB.

Comparison of pressure- and flow-triggered pressure-support ventilation on weaning parameters in patients recovering from acute respiratory failure.

OBJECTIVE: To compare the effects of pressure- and flow-triggered pressure-support ventilation on weaning parameters during recovery from acute respiratory failure. DESIGN: Prospective, randomized, clinical trial. SETTING: Intensive care unit in a university hospital. PATIENTS: Sixteen orotracheally intubated adult patients recovering from acute respiratory failure of various etiologies, without chronic obstructive pulmonary disease. INTERVENTIONS: Randomized application of pressure- and flow-triggered pressure-support ventilation at 100% and 75% ventilatory support levels in each triggering system. A total of four conditions were applied for 30 mins each in all patients. MEASUREMENTS AND MAIN RESULTS: Ventilatory, respiratory, and hemodynamic data were measured. For the measurement of weaning parameters, pressure and volume signals were directed to a computerized respiratory monitor by means of an esophageal probe and a flow sensor between the "Y" piece of the ventilatory circuit and the endotracheal tube. During both pressure-triggered (trigger sensitivity of -1 cm H2O) and flow-triggered (trigger sensitivity of 0.7 to 2.0 L/min) pressure-support ventilation with a ventilator, peak airway pressures were applied so as to decrease the work of breathing performed by the patient to zero (full ventilatory support). Partial ventilatory support was applied at 75% of the peak airway pressures achieved during full ventilatory support with each triggering system. A total of four experimental conditions were evaluated at identical FiO2 and positive and-expiratory pressure levels during pressure-support ventilation in each patient. Total ventilation volumes, arterial blood gas data, and hemodynamics did not differ among the four experimental conditions. During partial ventilatory support, the work of breathing, rapid shallow breathing index, and esophageal pressure increased significantly with both triggering systems when compared with data obtained at full ventilatory support. The mean data for the weaning parameters during the condition of partial ventilatory support were comparable between pressure- and flow-triggered pressure-support ventilation (i.e., 0.38 +/- 0.24 vs. 0.42 +/- 0.26 joule/L for work of breathing, 2.6 +/- 1.6 vs. 3.3 +/- 1.7 cm H2O for tracheal occlusion pressure, and 40.2 +/- 12.9 vs. 50.4 +/- 18.3 breaths/min/L for rapid shallow breathing index, respectively). CONCLUSIONS: The application of either a pressure- or flow-triggered system during pressure-support ventilation with the ventilator did not significantly affect short-term changes in gas exchange, respiratory mechanics, and inspiratory workload in patients recovering from acute respiratory failure of various etiologies without chronic obstructive pulmonary disease.

Respiratory and haemodynamic effects of conventional volume controlled PEEP ventilation, pressure regulated volume controlled ventilation and low frequency positive pressure ventilation with extracorporeal carbon dioxide removal in pigs with acute ARDS.

The purpose of this study was to evaluate whether any benefit of low frequency positive pressure ventilation with extracorporeal carbon dioxide removal (LFPPV-ECCO2R) existed over either volume controlled ventilation (VCV) with measured best-PEEP or pressure regulated volume controlled ventilation (PRVCV) with an inspiration/expiration (I/E) ratio of 4:1, with respect to arterial oxygenation, lung mechanics and haemodynamics, in acute respiratory failure. Fifteen adult pigs were used for the study. Respiratory failure was induced by surfactant depletion by repeated lung lavage. The different therapeutic approaches were applied randomly to each pig for 1 h. Measurements of gas exchange, airway pressures and haemodynamics were performed during ventilatory and haemodynamic steady state. Paco2 was kept constant in all modes. At almost similar total-PEEP, Pao2 values were significantly higher with LFPPV-ECCO2R compared to VCV with best-PEEP. Peak inspiratory pressure (PIP) and intrapulmonary pressure amplitude defined as the difference between PIP and total-PEEP were significantly lower with PRVCV and LFPPV-ECCO2R compared to VCV with best-PEEP. There was no significant difference between the modes concerning cardiocirculatory parameters. PRVCV with I/E ratio of 4:1 and LFPPV-ECCO2R proved to be better modes to achieve better gas exchange and lower PIP at lower intrapulmonary pressure amplitudes. It is concluded that PRVCV is an adequate form of treatment under these experimental conditions imitating acute respiratory failure, without necessitating other invasive measures.