Iapichino G

The role of total static lung compliance in the management of severe ARDS unresponsive to conventional treatment

A group of 36 patients with severe adult respiratory distress syndrome (ARDS) meeting previously established blood gas criteria (mortality rate 90%) became candidates for possible extracorporeal respiratory support [low frequency positive pressure ventilation with extracorporeal CO2 removal (LFPPV-ECCO2R)]. Before connecting the patients to bypass we first switched the patients from conventional mechanical ventilation with positive end expiratory pressure (PEEP) to pressure controlled inverted ratio ventilation (PC-IRV), and then when feasible, to spontaneous breathing with continuous positive airways pressure (CPAP). Forty eight hours after the patients had entered the treatment protocol, only 19 out of the 36 patients in fact required LFPPV-ECCO2R, while 5 were still on PC-IRV, and 12 were on CPAP. The overall mortality rate of the entire population was 23%. The only predictive value of success or failure of a particular treatment mode was total static lung compliance (TSLC). No patients with a TSLC lower than 25 ml (cm H2O)-1 tolerated either PC-IRV or CPAP, while all patients with a TSLC higher than 30 ml (cm H2O)-1 were successfully treated with CPAP. Borderline patients (TSLC between 25 and 30 ml (cm H2O)-1) had to be treated with PC-IRV for more than 48 h, or were then placed on LFPPV-ECCO2R if Paco2 rose prohibitively. We conclude that TSLC is a most useful measurement in deciding on the best management of patients with severe ARDS, unresponsive to conventional treatment.

Protein sparing and protein replacement in acutely injured patients during TPN with and without amino acid supply

The metabolic effects of TPN were studied in a selected group of trauma patients. Nineteen patients were randomly divided into two groups: the first was treated with glucose and insulin, the second with glucose, insulin and amino acids. Each patient in both groups received TPN isocaloric with respect to daily energy output and the treatment lasted five days. Each group was further divided into two subsets (severe or moderate catabolism) according to fasting energy output with respect to the expected energy expenditure. During the acute flow phase, both in moderate as well as in severe catabolism, glucose and insulin were effective for protein sparing; the maximum protein sparing effect was reached when giving a caloric intake equal to 130% of daily energy output. Glucose, insulin and amino acids were effective in replacement of nitrogen losses. In moderately catabolic patients nitrogen balance was significantly better than in severely catabolic patients. This study shows that early and short-term TPN is effective in controlling the flow phase of trauma. Glucose and insulin appear to be the determinants of the protein sparing effect when given in amounts equal to those needed; amino acids provided protein replacement when given in amounts equal to about 20% of energy output. Energy supply higher than 120–130% of daily energy output does not increase protein sparing and protein replacement, the only effect being a further increase in metabolism, which is possibly dangerous in critically ill patients.

The main determinants of nitrogen balance during total parenteral nutrition in critically ill injured patients

Factors influencing nitrogen balance during total parenteral nutrition have been investigated in 34 critically ill injured patients studied during the first 6 days after trauma. Basal nitrogen balance was severely negative (-0.26±0.12 (SD) g·kg-1), but improved consistently during treatment. Nitrogen intake proved to be the major determinant of a positive, or less negative, nitrogen balance, only secondarily followed by total energy intake corrected to predicted basal energy expenditure, according to multiple regression analysis. The amount of non-protein calories and the non-protein calorie to nitrogen ratio appeared to have little significance on nitrogen balance, when corrected for the two former variables.

Liver rupture after cardiopulmonary resuscitation (CPR) and thrombolysis.

Sir: It is well known that external cardiac massage (ECM) can cause serious visceral injuries [1]. Haemorrhagic complications may occur after cardiopulmonary resuscitation (CPR) and thrombolytic therapy [2, 3]. For this reason, CPR is considered by some authors to be a relative contraindication to thrombolysis independent of its duration [4], but others consider it a contraindication only if the rescue manoeuvers last more than 10 min [5]. The following report may help to define this open question. A male, 50 years old, affected by arterial hypertension, arrived in the hospital with high frequency, low voltage ventricular fibrillation. After several defibrillations and ECM for about 30 min along with standard intravenous therapy (lidocaine, adrenaline, bretylium tosylate, MgSO4), we observed stable cardiac electrical activity with left anterior hemiblock and right bundle branch block morphology and a 20±mm ST upward displacement in D1, aVL and from V1 to V6. 2D echocardiography showed marked hypocinesia of the cardiac apex and of interventricular septum. Then, a thrombolytic therapy (tissue-plasminogen activator) was administered followed by lidocaine 100 mg i. v. bolus, heparin 5000 IU bolus and 1000 IU/h infusion. Within 5 min of thrombolytic therapy the electrocardiographic signs of myocardical injury had almost disappeared. Arterial blood pressure (ABP) became measurable and sinus tachycardia (120 bpm) with several premature atrial and ventricular complexes appeared. Tachyarrhythmias were controlled by atenolol 2.5 mg i. v. bolus and lidocaine 1 mg/kg per h as a continuous infusion. Low ABP was treated with titrated dopamine infusion. Later on, we found ABP 90/50 mmHg, stable sinus rhythm (heart rate 90/min) with fewer premature beats. Nevertheless the patient was in postanoxic coma (Glasgow Coma Scale score = 4) and ventilated: expiratory flowrate VE 10.8 l/min, positive end-expiratory pressure (PEEP) 5 cmH2O, arterial oxygen tension/fractional inspired oxygen (PaO2/ FIO2) ratio 135, arterial carbondioxide tension (PaCO2) 36 mmHg, pH 7.41. Serum creatinine and urea were 97.2 mmol/l and 6.1 mmol/l, respectively. Two hours after admission to the emergency room, the patient was transferred to the intensive care unit Ventilatory assistance and dopamine (10 mg/kg per min) and lidocaine (1 mg/kg per h) treatment were continued. In the following 8 h, acceptable haemodynamic parameters were maintained. Small boluses of atenolol were given to an overall dose of 12.5 mg. In this phase we observed an improvement in blood gases (PaO2/FIO2 ratio 247, VE 12.5 l/min, PEEP 5 cmH2O, PaCO2 33 mmHg, pH 7.43), and the patient was kept sedated with fentanyl 0.01 mg/kg/min continuous infusion. At 20 h after hospital admission, acute circulatory failure (ABP 70/40 mmHg, heart rate 120/min, central venous pressure 7 mmHg, pulmonary artery wedge pressure 9 mmHg, pulmonary artery pressure 22 mmHg, cardiac index 2.19 l/m2, systemic vascular resistances 807 dyne/s per cm±5) was detected. We infused 2000 ml saline solution and 2 units of blood within 2 h because of suspected a haemorrage despite a haemoglobin of 10.7 g/dl. This intervention was ineffective as haemoglobin further decreased (9.1 g/dl), although melaena and/or gastrorrhagia had been excluded. 2D echocardiography showed a light septum hypocinesia, good global contractility and a widening of the thoracic aorta, suggesting a traumatic injury. The sudden worsening of clinical conditions precluded any surgical approach and the patient died within 30 min. Haemoperitoneum of about 2 l (due to laceration of the liver capsule coupled with left lobe intraparenchymal haematomas) and osteochondral joint fractures of the 4th, 5th and 6th right ribs were found at autopsy. No evidence of a ruptured aortic aneurysm was detected. This is a case of a patient with an acute myocardial infarction complicated by cardiac arrest managed with CPR and thrombolytic treatment. Recovery was, however, associated with a transitory low output state as well as severe hypoxia, which was probably produced by pulmonary edema secondary to acute myocardial dysfunction and/or prolonged ECM. Both improved during the immediate clinical course. We emphasize the efficacy of thrombolysis for reperfusion and to improve haemodynamics after myocardial infarction. However, at 20th h after hospital admission, the patient entered into irreversible shock, likely to be due to a haemorrage. At post-mortem examination, 2 l of blood was found in the abdomen due to rupture of the liver likely to have been caused by fractured ribs. We cannot exclude the possibility that some of the drugs (fentanyl, lidocaine), and particularly atenolol, given to reduce myocardial oxygen consumption and to counteract the proarrythmic effects of sympathetic activation, could have potentiated the low output condition and induced low systemic vascular resistance. In conclusion, this case report demonstrates the risks of administering thrombolytic therapy when CPR lasts more than 15±20 min. We therefore suggest that more than 10 min of CPR, even in expert hands, could be a contraindication to thrombolytic therapy due to the high risk of visceral injures. However, in a resuscitated (even with less 10 min of CPR) patient treated for thrombolysis who develops low blood pressure and tachycardia, the possibility of visceral injuries should be taken very seriously and cannot be excluded on the basis of a 2D transthoracic echocardiogram. On the other hand, in this kind of situation, acute percutaneous transluminal coronary angioplasty must be considered the best option, if available.

Main nitrogen balance determinants in malnourished patients

Factors influencing nitrogen balance during total parenteral nutrition have been investigated in 38 malnourished patients studied for a cumulative period of 280 days. According to multiple regression analysis, nitrogen intake (0.213±0.004 g kg-1 day-1, mean ±SD) proved to be the major determinant of a positive nitrogen balance (0.018±0.004 g kg-1 day-1), followed by non-protein energy intake (43.3±0.5 kcal kg-1 day-1). Total calorie intake to predicted basal energy expenditure and non protein calorie to nitrogen ratios appeared to have little significance on nitrogen balance, when corrected for the two former variables.

Combined use of mask CPAP and minitracheotomy as an alternative to endotracheal intubation : preliminary observation

We describe the combined use of mask CPAP (continuous positive airway pressure) and minitracheotomy as an alternative to conventional endotracheal intubation in 3 patients requiring CPAP, secretion removal and diagnostic procedures such as bronchoalveolar lavage and bronchial cultures. These requirements were fulfilled with the combined technique approach, thus preserving glottic function and avoiding the disadvantages of endotracheal intubation or trachectomy. This approach seems particularly suitable in the treatment of immunocompromised patients because of its reduced invasiveness.

Prevalence Of "Flat-Line" Thromboelastography During Extracorporeal Membrane Oxygenation For Respiratory Failure In Adults

We evaluated the prevalence of a thromboelastography reaction time (R time) >90 min (“flat-line”) reversible with heparinase during extracorporeal membrane oxygenation (ECMO). We evaluated the association between “flat-line” thromboelastography, other coagulation tests, and risk of bleeding during ECMO. Thirty-two consecutive patients on ECMO were included. Anticoagulation was provided by continuous infusion of unfractionated heparin to maintain an activated partial thromboplastin time (aPTT) ratio between 1.5 and 2.0. Activated clotting times (ACTs) thromboelastography without and with heparinase were measured. Occurrence of bleeding was recorded. Median heparin infusion rate was 16 (12–20) IU/kg/h, aPTT ratio was 1.67 (1.48–1.96), and ACT was 173 (161–184) sec. One hundred forty-five (46%) of 316 paired thromboelastography samples were “flat lines” all reversed with heparinase. Patients with “flat-line” thromboelastography received more heparin (p = 0.001) but had similar platelet count (p = 0.164) and fibrinogen level (p = 0.952) than those without. Activated partial thromboplastin time, ACT, and R time without heparinase weakly correlated between each other (Spearman correlation ⩽0.36) with poor agreement (Cohen’s &kgr; ⩽0.10). Major bleeding occurred in seven (22%) patients. Bleeding during ECMO was not predicted by any of the used test. In conclusion, adjusting heparin infusion to maintain aPTT ratio between 1.5 and 2.0 frequently resulted in “flat-line” thromboelastography.

Validation of computed tomography for measuring lung weight

BackgroundLung weight characterises severity of pulmonary oedema and predicts response to mechanical ventilation. The aim of this study was to evaluate the accuracy of quantitative analysis of thorax computed tomography (CT) for measuring lung weight in pigs with or without pulmonary oedema.MethodsThirty-six pigs were mechanically ventilated with different tidal volumes and positive end-expiratory pressures that did or did not induce pulmonary oedema. After 54 h, they underwent thorax CT (CTin vivo) and were then sacrificed and exsanguinated. Fourteen pigs underwent a second thorax CT (CTpost-exsang.) after exsanguination. Lungs were excised and weighed with a balance (balancepost-exsang.). Agreement between lung weights measured with the balance (considered as reference) and those estimated by quantitative analysis of CT was assessed with Bland-Altman plots.ResultsOne animal unexpectedly died before CTin vivo. In 35 pigs, lung weight measured with balancepost-exsang. was 371 ± 184 g and that estimated with CTin vivo was 481 ± 189 g (p < 0.001). Bias between methods was −111 g (−35%) and limits of agreement were −176 (−63%) and −46 g (−8%). Measurement error was similar in animals with (−112 ± 45 g; n = 11) or without (−110 ± 27 g; n = 24) pulmonary oedema (p = 0.88). In 14 pigs with thorax CT after exsanguination, lung weight measured with balancepost-exsang. was 342 ± 165 g and that estimated with CTpost-exsang. was 352 ± 160 g (p = 0.02). Bias between methods was −9 g (−4%) and limits of agreement were −36 (−11%) and 17 g (3%). Measurement errors were similar in pigs with (−1 ± 26 g; n = 11) or without (−12 ± 7 g; n = 3) pulmonary oedema (p = 0.12).ConclusionsCompared to the balance, CT obtained in vivo constantly overestimated the lung weight, as it included pulmonary blood (whereas the balance did not). By contrast, CT obtained after exsanguination provided accurate and reproducible results.

Point-of-Care Coagulation Tests Monitoring of Direct Oral Anticoagulants and Their Reversal Therapy: State of the Art.

&NA; Direct oral anticoagulants (DOACs) exert similar anticoagulant effects to vitamin K antagonists and are increasingly used worldwide. Nevertheless, an evidence‐based approach to patients receiving DOACs when any unplanned urgent surgery or bleeding (either spontaneous or traumatic) occurs is still missing. In this review, we investigate the role of point‐of‐care coagulation tests when other, more specific tests are not available. Indeed, thromboelastography and activated clotting time can detect dabigatran‐induced coagulopathy, while their accuracy is limited for apixaban and rivaroxaban, mostly in cases of low drug plasma concentrations. These tests can also be used to guide the reversal of DOAC‐induced coagulopathy providing a quick, before‐and‐after picture in case of therapeutic use of hemostatic compounds.

High positive end-expiratory pressure: only a dam against oedema formation?

IntroductionHealthy piglets ventilated with no positive end-expiratory pressure (PEEP) and with tidal volume (VT) close to inspiratory capacity (IC) develop fatal pulmonary oedema within 36 h. In contrast, those ventilated with high PEEP and low VT, resulting in the same volume of gas inflated (close to IC), do not. If the real threat to the blood-gas barrier is lung overinflation, then a similar damage will occur with the two settings. If PEEP only hydrostatically counteracts fluid filtration, then its removal will lead to oedema formation, thus revealing the deleterious effects of overinflation.MethodsFollowing baseline lung computed tomography (CT), five healthy piglets were ventilated with high PEEP (volume of gas around 75% of IC) and low VT (25% of IC) for 36 h. PEEP was then suddenly zeroed and low VT was maintained for 18 h. Oedema was diagnosed if final lung weight (measured on a balance following autopsy) exceeded the initial one (CT).ResultsAnimals were ventilated with PEEP 18 ± 1 cmH2O (volume of gas 875 ± 178 ml, 89 ± 7% of IC) and VT 213 ± 10 ml (22 ± 5% of IC) for the first 36 h, and with no PEEP and VT 213 ± 10 ml for the last 18 h. On average, final lung weight was not higher, and actually it was even lower, than the initial one (284 ± 62 vs. 347 ± 36 g; P = 0.01).ConclusionsHigh PEEP (and low VT) do not merely impede fluid extravasation but rather preserve the integrity of the blood-gas barrier in healthy lungs.