Prognostic merit of N-terminal-proBNP and N-terminal-proANP in mechanically ventilated critically ill patients

Background: Amino‐terminal fragments of type‐A and type‐B natriuretic peptide prohormones (NT‐proBNP, NT‐proANP) are powerful prognostic markers in patients with cardiac disease, and NT‐proBNP has been demonstrated to predict outcome in severe sepsis and septic shock. We assessed the prognostic value of NT‐proBNP and NT‐proANP in a consecutive series of mechanically ventilated intensive care patients and compared their prognostic merit. Methods: Seventy unselected patients admitted to the intensive care unit (ICU) were included in the study 48 h after start of controlled mechanical ventilation. Venous blood was obtained on inclusion and assayed for NT‐proBNP and NT‐pro ANP. Univariate and multivariate logistic regression analysis was used to assess the association of NT‐proBNP and NT‐proANP levels with 30‐day mortality. Established risk factors and possible confounders were used as covariates. Discrimination of different prognostic models was assessed calculating the area under the receiver‐operating characteristics curve (ROC‐AUC). Results: NT‐proBNP and NT‐proANP levels were higher in non‐survivors (n=25) than in 30‐day survivors (n=45). Log NT‐proBNP [odds ratio (OR) 2.34, 95% CI 1.17–4.66], and log NT‐proANP (OR 2.44, 95% CI 1.12–5.30) were independently predictive of increased mortality. A prior diagnosis of chronic obstructive lung disease was predictive of decreased mortality (OR 0.29, 95% CI 0.08–1.00). The relative prognostic values, evaluated by the ROC‐AUCs of NT‐proBNP (AUC 0.74, 95% CI 0.61–0.86) and NT‐proANP (AUC 0.73, 95% CI 0.61–0.86), were nearly identical. Conclusions: High NT‐proANP and NT‐proBNP levels associated with decreased short‐term survival in unselected, mechanically ventilated ICU patients. NT‐proANP performed equally well as a prognostic indicator as NT‐proBNP, and may represent a clinically useful alternative to NT‐proBNP.     

Subjective sleep assessment compared to polysomnography in mechanically ventilated critically ill ICU patients

Sleep deprivation is expected in the intensive care unit (ICU) and is associated with delirium and increased mortality. Polysomnography (PSG) is the gold standard for sleep assessment, but practical issues limit the method. Hence, many ICUs worldwide use subjective sleep assessment (SSA) for sleep monitoring, but the agreement between SSA and PSG is unknown. The hypothesis was that the level of agreement between SSA and PSG was low and that total sleep time (TST) assessed with SSA would be overestimated compared to PSG in this existing cohort database. In this sub-analysis, 30 consecutive study participants underwent 15-h PSG recordings during two consecutive nights. The attending nurse performed an hourly subjective observer rating of sleep quantity during both nights, and the agreement between SSA and PSG was determined along with mean TST. Primary outcome: The level of agreement between SSA and PSG determined by Bland–Altman analysis. Secondary outcome: (1) The overall mean TST estimated by SSA compared to PSG in all study participants enrolled in the main study during both study nights, (2) TST for all study participants evaluated hourly during both study nights, (3) TST assessed with SSA compared to PSG in study participants sedated with dexmedetomidine during the second night and for study participants treated with placebo or non-sedation the first and second nights. The level of agreement between SSA and PSG was low. Mean TST estimated by SSA during the time interval 4.00 p.m. to 7.00 a.m. was 481 min (428;534, 95% CI) vs. PSG at 437 min (386;488, 95% CI) (p = .05). When sedated with dexmedetomidine, TST estimated using SSA was 650 min (571;729, 95% CI) versus PSG which was 588 min (531;645, 95% CI) (p = 0.56). For participants treated with placebo or non-sedation TST estimated with SSA was 397 min (343;450, 95% CI) versus PSG at 362 min (302;422, 95% CI) versus (p = 0.17). In mechanically ventilated critically ill ICU patients, the level of agreement between SSA and PSG was low, and there was a significant overestimation of mean TST. SSA should only be used under awareness that it is imprecise and overestimates TST.     

Bispectral index correlates well with Richmond agitation sedation scale in mechanically ventilated critically ill patients

Purpose  

The clinical sedation scores available for assessing sedation in the intensive care unit (ICU) have drawbacks and limit their usefulness in paralyzed and deeply sedated patients. An objective tool, the bispectral index (BIS), could prove beneficial in such circumstances. We evaluated the ability of BIS to assess the level of sedation and its correlation with the Richmond agitation sedation scale (RASS) in ICU.     

Validation of a behavioral pain scale in critically ill, sedated, and mechanically ventilated patients

Assessing pain in critically ill patients, particularly in nonverbal patients, is a great challenge. In this study, we validated a behavioral pain scale (BPS) in critically ill, sedated, and mechanically ventilated patients. The BPS score was the sum of 3 subscales that have a range score of 1-4: facial expression, upper limb movements, and compliance with mechanical ventilation. Two assessors observed and scored pain simultaneously with the BPS at rest and during painful procedures. The psychometric properties of the BPS that were studied were reliability, validity, and responsiveness. We achieved 360 observations in 30 patients. The BPS was internally reliable (Cronbach alpha = 0.72). The intraclass correlation coefficient to evaluate inter-rater reliability was high (0.95). Validity was demonstrated by the change in BPS scores, which were significantly higher during painful procedures, with averages of 3.9 +/- 1.1 at rest and 6.8 +/- 1.9 during procedures (P < 0.001), and by the principal components factor analysis, which revealed a large first-factor accounting for 65% of the variance in pain expression. The BPS exhibited excellent responsiveness, with an effect size ranging from 2.2 to 3.4. This study demonstrated that the BPS can be valid and reliable for measuring pain in noncommunicative intensive care unit patients.     

Hemodynamic and pulmonary changes after drainage of significant pleural effusions in critically ill, mechanically ventilated surgical patients

PURPOSE: Our purpose was to study the effects of drainage of significant pleural effusions in mechanically ventilated patients in a surgical intensive care unit. METHODS: Twenty-two ventilated patients in the surgical intensive care unit of a tertiary care center over a 12-month period who developed a pleural effusion large enough to require drainage were studied prospectively. All patients underwent serial portable chest radiography in the upright or semiupright position; the radiographs were reviewed by a radiology attending. Pleural effusions were classified as small, moderate, or large. Moderate or larger effusions were drained using an 8- to 12-Fr pigtail catheter inserted at the bedside under ultrasound guidance. Hemodynamic and pulmonary parameters were collected before and after the fluid was drained. Parameters studied included those outlined in the physiologic profile and included measured and calculated physiologic variables, arterial blood gas measurements, and Svo2 measurements. Ventilator settings before and after were also recorded. RESULTS: Average initial pleural effusion drainage was 1,262 +/- 762 mL (range, 300-2,980 mL). Nine of the 22 patients had effusions drained from both the right and left chest. Blood pressure, systemic vascular resistance, Po2, Pco2, Svo2, Fio2, peak airway pressure, and spontaneous volume did not change significantly. Pulmonary capillary wedge pressure decreased (17.4 +/- 6.0 before, 13.6 +/- 4.4 after; p < 0.01), central venous pressure decreased (14.2 +/- 5.2 before, 11.5 +/- 4.4 after; p < 0.02), and pulmonary arteriovenous shunt decreased (26.7 +/- 15.1 before, 21.0 +/- 7.8 after; p < 0.04). Oxygen delivery increased (579.7 +/- 214.7 before, 662.8 +/- 263.3 after; p < 0.01) and oxygen consumption increased (146.3 +/- 61.6 before, 175.2 +/- 73.8 after; p < 0.01). Respiratory rate also decreased (19.4 +/- 6.5 before, 15.5 +/- 6.3 after; p < 0.05). There were no complications from the placement of the pigtail catheters. CONCLUSION: Drainage of pleural effusions results in increased oxygen delivery and oxygen consumption coinciding with a decrease in pulmonary capillary wedge pressure. The pulmonary arteriovenous shunt decreased, implying an increase in functional residual capacity and improved oxygenation. Further study is needed to determine whether these changes lead to an improved patient outcome (i.e., reduction in length of stay, ventilator days, or mortality).     

Current practices in sedation and analgesia for mechanically ventilated critically ill patients: a prospective multicenter patient-based study

BACKGROUND: The authors conducted a patient-based survey of practices to fully describe the assessment and the management of pain and sedation of a large cohort of mechanically ventilated patients during their first week of intensive care unit (ICU) stay. METHODS: A total of 1,381 adult patients were included in a prospective, observational study in 44 ICUs in France. Pain and sedation assessment, analgesic and sedative use, and analgesic management during procedural pain were collected on days 2, 4, and 6 of the ICU stay. RESULTS: The observed rates of assessment on day 2 for sedation (43%) and analgesia (42%) were significantly smaller than that of use of sedatives (72%) and opioids (90%), also noted on days 4 and 6. The use of protocols/guidelines for sedation/analgesia in the ICU reduced the proportion of patients who were treated, although not evaluated. A large proportion of assessed patients were in a deep state of sedation (40-50%). Minor changes in the dosages of the main prescribed agents for sedation (midazolam, propofol) and analgesia (sufentanil, fentanyl, morphine, remifentanil) were found across 6 days of the patient's ICU stay. Procedural pain was specifically managed for less than 25% of patients; during those procedures, the proportion of patients with pain significantly increased from the baseline pain evaluation. CONCLUSIONS: Excessively deep states of sedation and a lack of analgesia during painful procedures must be prevented. To facilitate systematic pain and sedation assessment and to adjust daily drug dosages accordingly, it seems crucial to promote educational programs and elaboration of protocols/guidelines in the ICU.     

Remifentanil versus morphine analgesia and sedation for mechanically ventilated critically ill patients: a randomized double blind study

BACKGROUND: The rapid onset and offset of action of remifentanil could make it quickly adjustable to the required level of sedation in critically ill patients. The authors hypothesized that the efficacy of a remifentanil-based regimen was greater than that of a morphine-based regimen. METHODS: Forty intent-to-treat patients were randomly allocated to receive a blinded infusion of either remifentanil 0.15 microg x kg(-1) x min(-1) or morphine 0.75 microg x kg(-1) x min(-1). The opioid infusion was titrated, in the first intent, to achieve optimal sedation defined as Sedation Agitation scale of 4. A midazolam open-label infusion was started if additional sedation was required. RESULTS: The mean percentage hours of optimal sedation was significantly longer in the remifentanil group (78.3 +/- 6.2) than in the morphine group (66.5 +/- 8.5). This was achieved with less frequent infusion rate adjustments (0.34 +/- 0.25 changes/h) than in the morphine group (0.42 +/- 0.22 changes/h). The mean duration of mechanical ventilation and extubation time were significantly longer in the morphine group (18.1 +/- 3.4 h, 73 +/- 7 min) than in the remifentanil group (14.1 +/- 2.8 h, 17 +/- 6 min), respectively. Remifentanil mean infusion rate was 0.13 +/- 0.03 microg x kg(-1) x min(-1), whereas morphine mean infusion rate was 0.68 +/- 0.28 microg x kg(-1) x min(-1). More subjects in the morphine group (9 of 20) than in the remifentanil group (6 of 20) required midazolam. The incidence of adverse events was low and comparable across the two treatment groups. CONCLUSIONS: A remifentanil-based regimen was more effective in the provision of optimal analgesia-sedation than a standard morphine-based regimen. The remifentanil-based regimen allowed a more rapid emergence from sedation and facilitated earlier extubation.     

Electrolyte and metabolic disturbances in critically ill patients

Electrolyte and metabolic disturbances are common in the critically ill patient. Hyponatraemia is most frequently caused by the syndrome of inappropriate antidiuretic hormone secretion. Over-rapid correction of hyponatraemia is associated with osmotic demyelinating syndromes, and sodium rise should usually be restricted to less than 10 mmol/day. Hypernatraemia is caused by a loss (e.g. diabetes insipidus after head injury) or inadequate administration of free water. It is treated by correction of the free water deficit with either intravenous 5% dextrose or water via a nasogastric tube. Prompt administration of desmopressin in diabetes insipidus will prevent severe hypernatraemia. Hypokalaemia is a frequent electrolyte disorder, associated with cardiac arrhythmias and is treated with intravenous infusions of potassium chloride of up to 40 mmol/hour. Hypomagnesaemia often co-exists and is associated with cardiac arrhythmias, muscle weakness and seizures. Correction of hypophosphataemia has been associated with improved cardiac and respiratory muscle function. The hyperglycaemic syndromes include diabetic ketoacidosis (DKA) and hyperosmolar non-ketotic hyperglycaemic syndrome (HNHS). DKA arises because of an absolute insulin deficiency causing hyperglycaemia and ketogenesis. This leads to dehydration, hypovolaemia and a metabolic acidosis. HNHS is due to a relative insulin deficiency from peripheral insulin resistance and is associated with profound hyperglycaemic dehydration without ketosis and acidosis. Both conditions are treated with intravenous fluid replacement, insulin infusion and correction of associated electrolyte disorders, including hypokalaemia and hypophosphataemia. There will be an underlying condition precipitating the hyperglycaemic syndrome (e.g. sepsis, acute coronary syndrome), which will also need to be treated.     

Temporary stenting of acquired benign tracheoesophageal fistulas in critically ill ventilated patients

Background: To evaluate the use of esophageal stents for temporary sealing of acquired benign tracheoesophageal fistulas developed in critically ill, ventilated patients.Methods: This is a retrospective analysis (1992–2003) of the data of 12 mechanically ventilated patients — six of them after major or multiple trauma — being intubated for a median of 30 days before they develop an acquired benign tracheoesophageal fistula. Five of them were in sepsis. Two types of stents were used: the Wilson-Cook esophageal balloon plastic stent in the first four cases and the Ultraflex covered self-expandable stent in the remaining eight. The total procedure was performed at bedside in the intensive care unit, with no special need for supplementary anesthesia or fluoroscopic control.Results: Stent implantation was technically successful in all patients and fistula occlusion was achieved in every case. There was no stent migration and fistulas remained sealed until death or upon decision for removal. Nine patients died between 5 days and 2 months after stent placement, as a result of their diseases. Three patients were referred for fistula surgical repair 33, 36, and 43 days after stent placement. Before surgery the stents were easily removed under direct vision.Conclusion: Temporary closure of an acquired tracheoesophageal fistula developed in critically ill ventilated patients is an easy, bedside-applicable, safe, and effective palliative procedure, with no complications or mortality.     

Resting metabolic rate of the critically ill patient: measured versus predicted

Critically ill patients requiring mechanical ventilation are particularly susceptible to malnutrition. A knowledge of the energy requirements of these patients is essential in designing nutritional regimens. This study examines 45 resting energy-expenditure measurements performed in a group (n = 40) of postoperative, critically ill patients who were hemodynamically stable, noncomatose, and receiving mechanical ventilation. It examines in particular to what degree the resting energy expenditure of such patients can be predicted using the Harris-Benedict and Aub-Dubois formulae. Resting energy expenditure was measured using indirect calorimetry. There was only a moderate correlation between measured resting energy expenditure and that predicted using the Harris-Benedict (r = 0.57) and Aub-Dubois (r = 0.59) formulae. There was little correlation between the ratio of the measured to the predicted (Harris-Benedict) resting energy expenditure and age, or the ratio of actual to ideal body weight and body weight. The measured resting energy expenditure differed widely (70-140%) from predicted, reflecting the many complex factors that influence these patients' metabolic rate. The role of standard predictive formulae in such patients is as an arbitrary reference point to be used to define hypermetabolism (measured greater than predicted) and hypometabolism (predicted greater than measured).     

Design of an automated system for assessing metabolic function in mechanically ventilated patients

This paper describes the design of a fully automated self calibrated measurement system which can be connected to any commercial ventilator. The machine measures the oxygen consumption and carbon dioxide production. The instrument is based on commercially available analysers. An inexpensive microprocessor performs the computations, displays the results and leads the calibration's and measure's procedures. The apparatus is presently tested in clinical practice.     

外科机械通气重症患者静息能量代谢评估

目的 比较间接能量测定法测定的机械通气条件下外科重症患者静息能量代谢值与Harris-Benedict公式法和体重法计算值的差异,探讨外科重症患者静息能量代谢评估方法.方法 以2014年4月-2015年4月在首都医科大学宣武医院外科重症监护室接受机械通气的29例重症患者为研究对象,共纳入患者29例,其中男性13例,女性16例,测量静息能量代谢值188例次.采用间接能量测定法测定机械通气后第1、3、5天的静息能量代谢值,与根据身高、体重采用Harris-Benedict公式法和体重法所计算的静息能量代谢值比较,采用配对样本t检验方法分析重症患者代谢水平分布规律,探讨不同方法计算的静息能量代谢值之间的差异性.结果 根据Harris-Benedict公式法计算标准分析患者代谢水平分布规律:低代谢状态1 17次(62.24％),正常状态59次(31.38％),高代谢状态12次(6.38％).其中18例患者采用3种方法测得的第1、3、5天静息能量代谢值:间接能量测定法为(1 627.11±323.63) kcal、(1 614.67±308.93) kcal、(1 576.11±263.96) kcal;体重法为(1 479.44±200.24) kcal、(1 488.40±227.72) kcal、(1 434.14±216.56) kcal;Harris-Benedict公式法为(1 777.43±253.00) kcal、(1 730.08±265.18) kcal、(1 689.33±236.69) kcal.分析得出通过Harris-Benedict公式法和体重法测得的静息能量代谢值与通过间接能量测定法测得值均存在显著差异,Harris-Benedict公式法显著高于间接能量测定法(均P＜0.05),体重法显著低于间接能量测定法(均P ＜0.05).结论 虽然Harris-Benedict公式法和体重法临床上使用简便易行,但与间接能量测定法测定结果仍有较大差距.临床应尽量按照间接能量测定法测得的静息能量代谢值提供营养支持.     

A lack of evidence of superiority of propofol versus midazolam for sedation in mechanically ventilated critically ill patients: a qualitative and quantitative systematic review

Propofol and midazolam are often used for sedation in the intensive care unit. The aim of this systematic review was to estimate the efficacy and harm of propofol versus midazolam in mechanically ventilated patients. A systematic search (Medline, Cochrane Library, Embase, bibliographies), any language, up to June 1999 was performed for reports of randomized comparisons of propofol with midazolam. Data from 27 trials (1624 adults) were analyzed. The average duration of sedation varied between 4 and 339 h. In 10 trials, the duration of adequate sedation was longer with propofol (weighted mean difference 2.9 h; 95% confidence interval [CI], 0.2-5.6 h). In 13 trials (mostly postoperative), sedation lasted 4 to 35 h; in 9 of those, average weaning time from mechanical ventilation with propofol was 0.8-4.3 h; with midazolam it was 1.5-7.2 h (weighted mean difference 2.2 h [95% CI, 0.8 to 3.7 h]). In 8 trials, sedation lasted 54 to 339 h; there was a lack of evidence for difference in weaning times. Arterial hypotension (relative risk 2.5 [95% CI, 1.3 to 4.5]; number-needed-to-treat, 12), and hypertriglyceridemia (relative risk 12.1 [95%CI, 2.9 to 49.7]; number-needed-to-treat, 6) occurred more often with propofol. The duration of adequate sedation time is longer with propofol compared with midazolam. In postoperative patients with sedation <36 h, weaning is faster with propofol. Implications: The duration of adequate sedation time is longer with propofol compared with midazolam. In postoperative patients with sedation < 36 h, weaning is faster with propofol.     

机械通气患者口腔护理效果研究

目的了解机械通气患者口腔护理效果。方法采用便利抽样法选取某三级甲等医院ICU收治的47例机械通气患者,常规口腔护理后检测中切牙、侧切牙、尖牙及第一前磨牙共16颗牙邻面及颈部残留牙菌斑量。结果经口腔护理后,47例患者被检牙均残留不同程度牙菌斑,其中,牙邻面菌斑残留量显著多于牙颈部;随牙位后移,各部位菌斑量显著增加(均P<0.05)。不同象限同一牙位菌斑残留量差异无统计学意义(均P>0.05)。结论现行口腔护理方法清除牙菌斑效果不理想,尤其是后牙远中邻面菌斑清除困难,有待改良护理技术以提高口腔护理质量。     

Assessment of volume responsiveness in mechanically ventilated patients

Monitoring and management of intravascular volume status is of crucial importance in critically ill patients. Hypovolemia, induced by hemorrhage or pathologic fluid shifts in the presence of systemic inflammation, is frequently the cause for hemodynamic instability and hypotension. This deficit of central blood volume leads to a reduction in biventricular cardiac preload. With respect to the Frank-Starling mechanism, this causes an alteration in left ventricular stroke volume. If this reduction in stroke volume cannot be compensated by an increase in heart rate, this finally results in a decline of cardiac output. In this clinical situation fluid loading is the treatment of choice. However, insufficient peripheral vascular resistance and thus reduced cardiac afterload as well as impaired myocardial contractility also have to be taken in account to be causative for hypotension. Potential hazards of fluid loading specifically in the latter situation include pulmonary edema, worsening of pulmonary gas exchange and myocardial failure. Thus, prediction of fluid responsiveness, i.e. the prediction of the hemodynamic response to fluid loading is of utmost importance in critically ill patients. Several conventional parameters of systemic hemodynamic monitoring such as the cardiac filling pressures CVP and PAOP, the estimation of the left ventricular end-diastolic area (LVEDA) by echocardiography and measurement of central blood volumes as the right-ventricular end-diastolic volume (RVEDV) or the global end-diastolic volume (GEDV) by thermodilution are frequently used for preload monitoring. Further, functional preload parameters such as the left ventricular stroke volume variation (SW), describing the specific interactions of the heart and the lungs under mechanical ventilation, have been recently proposed to be useful for predicting fluid responsiveness. Thus, it is the aim of the present article to analyze these different concepts of hemodynamic monitoring regarding their usefulness and clinical applicability to predict fluid responsiveness at the bedside.