Prevention of multiple systems failure

Extracorporeal life support and systemic inflammation

Extracorporeal life support (ECLS) encompasses a wide range of extracorporeal modalities that offer short- and intermediate-term mechanical support to the failing heart or lung. Apart from the daily use of cardiopulmonary bypass (CPB) in the operating room, there has been a resurgence of interest and utilization of veno-arterial and veno-venous extracorporeal membrane oxygenation (VA- and VV-ECMO, respectively) and extracorporeal carbon dioxide removal (ECCO₂R) in recent years. This might be attributed to the advancement in technology, nonetheless the morbidity and mortality associated with the clinical application of this technology is still significant. The initiation of ECLS triggers a systemic inflammatory response, which involves the activation of the coagulation cascade, complement systems, endothelial cells, leukocytes, and platelets, thus potentially contributing to morbidity and mortality. This is due to the release of cytokines and other biomarkers of inflammation, which have been associated with multiorgan dysfunction. On the other hand, ECLS can be utilized as a therapy to halt the inflammatory response associated with critical illness and ICU therapeutic intervention, such as facilitating ultra-protective mechanical ventilation. In addition to addressing the impact on outcome of the relationship between inflammation and ECLS, two different but complementary pathophysiological perspectives will be developed in this review: ECLS as the cause of inflammation and ECLS as the treatment of inflammation. This framework may be useful in guiding the development of novel therapeutic strategies to improve the outcome of critical illness.

MOF, MODS, and SIRS: what is in a name or an acronym?

The most prominent contributions to multiple organ failure, multiple organ dysfunction syndrome, and systemic inflammatory response syndrome are described in this article. However, it is quite possible that there are others that have been missed. The problem of organ failure continues to perplex clinicians and scientists, and it contributes to fatal outcomes for patients with illnesses, infections, and injuries after operations. Although we know a fair bit about these problems, we frequently can do little about it. The best approach remains support to prevent failure.

Deferoxamine and hespan complex as a resuscitative adjuvant in hemorrhagic shock rat model

The optimal type and amount of fluid for resuscitation of injured patients in hemorrhagic hypovolemic shock remains controversial. Use of deferoxamine, an iron chelator and oxygen-free radical scavenger, and hespan (hydroxyethyl starch), a colloid plasma expander, was evaluated in a rat hemorrhagic shock model. Eighty Sprague-Dawley male rats were utilized in four experiments. In these rats, bi-femoral cutdowns were performed for blood withdrawal, resuscitation, blood sampling, and continuous blood pressure monitoring. All rats, except control (with bilateral cutdown only), were bled and maintained at 40 mmHg for 90 min. The shed blood was returned and animals were resuscitated. One hour later, 2 mg/kg lidocaine was injected and blood samples were taken at 10, 15, 30, and 60 min for evaluation of lidocaine derivative monoethylglycinexylidide (MEGX) by fluorescent polarization immunoassay. In experiment 1 (n = 31), resuscitation with different volumes of Ringer's lactate (7.5 mL, 15.0 mL, and 30.0 mL/kg) was compared and 7.5 mL/kg LR was most beneficial. In experiment 2 (n = 22), resuscitation with three doses of Hespan (3.75 mL, 7.5 mL, and 15 mL/kg) was compared. A dose of 15 mL/kg significantly improved the liver function. In experiment 3 (n = 15), resuscitations with two doses of deferoxamine (30 mg and 100 mg/kg) were compared. A dose of 100 mg/kg significantly improved the liver function. In experiment 4 (n = 12), a combination of deferoxamine (100 mg/kg) and Hespan (3.75 and 7.5 mL) was used. Deferoxamine (100 mg/kg) complexed with 7.5 mL of Hespan was found the most beneficial resuscitation. This conjugate could be a choice as a resuscitative adjuvant in hypovolemic shock without any side effects.

Effect of lung contusion on surfactant composition in multiple-trauma patients

OBJECTIVE

The aim of this study was to investigate alterations of the surfactant system in multiple-trauma patients (MTP) with lung contusion and the influence of single- or multiple-organ dysfunction syndrome (OF/MOF) on the surfactant system.

SETTING

University hospital, trauma-intensive care unit.

DESIGN

Prospective, nonrandomized study.

METHODS

MTP with an Injury Severity Score > 19 points have been recorded prospectively since 1992. Bronchoalveolar lavages were obtained daily either until day 14 or extubation. Three groups of MTP were compared: noL: MTP, no lung contusion (n = 14); LuCo-: MTP, lung contusion, no OF/MOF (n = 17); LuCo+: MTP, lung contusion, with OF/MOF (n = 10). Also, surfactant samples of 11 healthy volunteers (Con) were investigated and compared with MTP. All data were presented as mean +/- SEM. Statistical analysis were performed using programs of SPSS 6.0.1. (univariate ANOVA, Fisher's Exact Test, p < = 0.05).

RESULTS

There were no differences in sex and age. Injury Severity Score was significantly impaired in group LuCo+ (44 +/- 4), compared with groups noL (31 +/- 3) and LuCo- (34 +/- 3). Group noL showed no statistical differences for lung function, total protein, and total phospholipid content of the bronchoalveolar lavage compared with group LuCo-. Furthermore, the relative content of phosphatidylcholine and phosphatidylglycerol in total phospholipids and surfactant-associated protein A were not significantly altered compared with group LuCo-. Lung function in group LuCo+ was significantly impaired and led to hypoxemia on the day of trauma. Total protein content and total phospholipids were significantly elevated in group LuCo+ compared with groups noL and LuCo- on the first day. Also, the relative content of phosphatidylcholine was significantly increased in group LuCo+ up to day 4, compared with groups noL and LuCo-. In comparison with groups noL and LuCo-, a significant decrease of the relative content of phosphatidylglycerol was obtained in group LuCo+ up to day 7. The surfactant-associated protein A was increased in group LuCo+ during the whole observation time, compared with the other groups.

CONCLUSIONS

Multiple trauma leads to alterations in the surfactant system. The composition of surfactant was not further influenced by lung contusion alone. Only MTP with OF/MOF during the intensive care unit treatment showed significant alterations in surfactant composition and a decrease in lung function.

Instantaneous restoration of regional organ blood flow after severe hemorrhage: effect of small-volume resuscitation with hypertonic-hyperoncotic solutions

The acute effects of small-volume infusion of hypertonic-hyperoncotic solutions on central hemodynamics, regional organ blood flow (RBF; 15-microns-diameter radiolabeled microspheres), and respiratory function following severe hemorrhage (MAP = 40 mm Hg for 45 min, approx 50% blood loss) were analyzed in anesthetized beagles. Treatment regimens used were: 10% Dextran 60 in 7.2% NaCl (HHS); 10% Dextran 60 in 0.9% NaCl (HDS); or 7.2% NaCl (HSS) alone, administered over 2 min in a volume equivalent to 10% of the blood loss (4 ml/kg iv). Within 5 min, cardiac output reached (HSS, HDS) or even exceeded prehemorrhage values (HHS), and MAP increased to 56% (HDS)-74% (HHS) of baseline. At the same time, RBF in kidneys (all groups), pancreas (HHS, HSS) and gastric mucosa (HHS) was completely restored, while flow in myocardium, brain, skeletal muscle, adrenal glands (all groups), and small intestine and colon (HHS) rose even above baseline values (P less than 0.05). Fractional blood flow (percentage of cardiac output) favored heart and brain in all three groups. These effects tended to persist for at least 30 min. Respiratory function was not affected by either of the three solutions, and no adverse effects were noted. Small-volume resuscitation with 7.2% saline/10% Dextran 60 provides instantaneous restitution of regional organ blood flow; it appears to result in a more uniform circulatory response than 7.2% saline or 10% Dextran 60 alone and might ensure improved organ perfusion during evacuation of patients from the accident site.

[Continuous monitoring of mixed venous oxygen saturation in anesthesia in pulmonary surgery]

The multiplicity of potential causes of variations in mixed venous oxygen saturation (SvO2) during one lung ventilation (OLV), including a constant ventilation/perfusion mismatch, explains that it has been suggested as a routine monitoring procedure. To assess its usefulness, 12 adults undergoing OLV were monitored during surgery with an Oximetrix pulmonary catheter, placed on the side opposite to the surgical field under fluoroscopic control. Seventy two complete sets of haemodynamic measurements were obtained at 6 different times during surgery. We studied the ability of changes in SvO2 to predict changes in arterial oxygen saturation (SaO2), cardiac output (CO), and venous admixture (VA) by calculating sensitivities (Se), specificities (Sp) and predictive values with regard to these variables. There were no complications due to the protocol. However left-sided catheter placement failed in four cases. Correlation between optical and measured SvO2 was very strong (r = 0.94; p less than 0.001). SvO2, oxygen consumption (VO2) and the rate of oxygen extraction remained constant throughout the procedure, even when CO, mean arterial pressure, VA, SaO2 and PaO2 varied. Clamping the pulmonary artery returned VA, SaO2 and PaO2 values to those found before OLV, but produced a significant decrease in CO. SvO2 had low Se and Sp for changes in other variables (CO: 76 +/- 7, 48 +/- 9; PaO2: 79 +/- 6, 59 +/- 9; VA: 54 +/- 7, 48 +/- 7 respectively). In this type of surgery, alterations in variables related to oxygen are probably balanced by haemodynamic changes. In fact, according to Fick's formula, SvO2 is almost completely determined by SaO2 and CO, when VO2 and haemoglobin remain stable.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of naloxone on microcirculatory behavior during irreversible hemorrhagic shock

Thirty-six male Sprague-Dawley rats were divided into three groups (n = 12): simple hemorrhagic shock group, saline-treated group, and naloxone-treated group. Synchronous videotape recording with two cameras was used to observe the relationship between the change of blood pressure and that of microcirculation of cremaster muscle. It has been suggested that the temporary plugging of capillaries by WBC may be the explanation for no reflow in microvessels after transfusion and infusion during the irreversible stage of shock. Administration of naloxone (2 mg/kg iv) followed by reinfusion of the shed blood is associated with an increase in blood pressure and pulse pressure. Coincidentally, a pulsatile movement of the blood, impacted on the stationary blood cells in capillaries, eventually dislodges them and leads to reperfusion of capillaries. Thereafter systemic blood pressure and carotid artery red blood cell velocity were increased and remained stable. The 24-hr survival rate was significantly increased in the naloxone-treated group (10/12), as compared with that in the saline-treated group (1/12). The mechanism of naloxone treatment is discussed. The suggestion is advanced that the effects on cardiac and microcirculatory performance may influence each other, and that both contribute to the pathogenesis of irreversible hemorrhagic shock.

Factors affecting outcome after chest injury

From 1978 to 1983 a total of 328 patients was admitted to Royal Newcastle Hospital Intensive Care Unit with chest injuries; 255 had other injuries as well. Of the 328, 171 developed acute respiratory failure, 174 received mechanical ventilation (159 for acute respiratory failure) and 46 died. The commonest causes of death were head injury (19), sepsis (10) and uncontrollable haemorrhage (10). Associated head (131) and/or abdominal (89) injuries tripled mortality. Those without respiratory, cardiac, renal or hepatic failure (155) had a mortality rate of 5.8% while the remainder had mortality rates of 21.6%, 12.5%, 37.5% and 100%, for respiratory (171), cardiac (8), renal (8) and hepatic (5) failures, respectively. Shock was present on admission in 55, of whom 19 died. Sepsis developed in 59 and 14 with this complication died. Sepsis remains a potentially avoidable late cause of death and attention needs to be directed towards limiting invasive techniques of management to those which are necessary, and towards early diagnosis of abdominal injuries with early exploratory surgery. The best chance of survival in the initial phase of injury may lie in the establishment of an integrated regional trauma centre system together with improved pre-hospital and retrieval systems.

Three-year experience with amikacin sulfate as an exclusive surgical aminoglycoside in a large acute-care hospital

Aminoglycosides have important roles as perioperative adjunctive antibiotics in the surgical management of peritonitis. In the past, most surgeons have used gentamicin in combination with a drug aimed at intraperitoneal anaerobic pathogens, either clindamycin or metronidazole. Amikacin has been traditionally reserved for culture-proved infections due to gram-negative organisms resistant to gentamicin or other aminoglycosides. At the Minneapolis Veterans Administration Medical Center, a worrisome incidence of gentamicin-resistant hospital isolates led to a decision to make amikacin the exclusive, routine surgical aminoglycoside for all abdominal infections, as well as all hospital-acquired infections in surgical patients involving gram-negative aerobes and requiring parenteral therapy. This report describes the resultant three-year experience with amikacin in surgical patients. Data from four research studies involving these patients suggest that exclusive amikacin use has not led to the emergence of amikacin-resistant organisms or to significant nephrotoxicity. Amikacin use in surgical patients is supported in hospital environments where gentamicin resistance is judged to be a significant clinical risk factor.

Ruptured aortic aneurysms: postoperative complications and their aetiology

A review of 198 ruptured aortic aneurysms has been undertaken, this being 36.3 per cent of all the aneurysms treated during the period 1960-81. The overall mortality rate was 42.9 per cent. The peroperative mortality was 6.6 per cent and the mortality of the patients who survived the operation was 38.9 per cent. Factors which influenced postoperative mortality were the age of the patient, the distance travelled to hospital, the presence of an intraperitoneal bleed, the duration of the operative procedure and the volume of blood transfused, but only the amount of blood transfused had a statistically significant influence on mortality. However, as the highest mortality associated with any of these risk factors was 54.9 per cent, no single factor alone can be considered a contra-indication to operation. As there are no reliable predictive factors, we believe that all cases with clinically ruptured aortic aneurysms should have a laparotomy and resection. The most common postoperative complications were varying degrees of renal and respiratory insufficiency and the occurrence of these was significantly associated with the volume of blood transfused.

Cellular energetics and ATP-MgCl2 therapy in sepsis

Studies in rats with a clinically relevant form of peritonitis indicate that tissue adenine nucleotide levels do not decrease in the early stages of sepsis. In contrast, hepatocellular active transport appears to be depressed even in the very early stages of sepsis. In late sepsis, however, tissue adenine nucleotide levels decrease significantly because of inadequate perfusion associated with peritonitis. Reticuloendothelial function (RES) is also significantly depressed at the late stages of sepsis. Administration of saline, glucose, or ATP-MgCl2 alone following sepsis does not produce any beneficial effects on survival. However, administration of high concentrations of ATP-MgCl2 together with hypertonic glucose results in a significant improvement in the survival of animals. This treatment regimen restores cellular ATP levels and also restores the depressed RES function to normal within three hours. Thus, extirpation of the lesion producing the septic process, combined with metabolic support, proves helpful without antibiotic treatment.