[Bioethical interpretation of intensive care] . / Per una lettura in chiave bioetica delle terapie intensive.

The bioethical interpretation concerns both those receiving intensive care (IC) and the nature of the treatment itself. The principle of autonomy expressed in the doctor-patient relationship is achieved through the use of informed consent and may also be used in the unique context of patients in IC. Organ-function replacement treatment raises the ethical question of the definition and management of the limit to treatment. The appropriateness of IC can be defined by clinical and ethical criteria and aims to avoid inappropriately excessive treatment. In order to improve the decision-making process involving bioethical questions, the authors outline a number of working approaches: the use of informed consent even in IC, the possible role of Advanced Directives in IC, epidemiological studies, operator training.

Cerebral hemodynamic response to CO2 after severe head injury: clinical and prognostic implications.

OBJECTIVE: To study the cerebrovascular reactivity to CO2 after severe head injury to establish the clinical and prognostic relevance of CO2 reactivity. METHODS: Cerebrovascular reactivity to CO2 was studied in 20 patients with severe head injuries at 3.0+/-1.8 days after trauma onset. Two cerebral blood flow studies were performed to measure CO2 reactivity: the first study in a condition of normocapnia and the second study in a condition of relative hypocapnia. RESULTS: Global reactivity was superimposable to that found in awake, normocapnic subjects and did not correlate with age and Glasgow Coma Scale score but was dependent on the type of brain lesion. Moreover, reactivity correlated with outcome in patients studied after the first 3 days after trauma. CONCLUSIONS: Our data suggest that cerebrovascular reactivity is (a) almost preserved after a severe head injury; (b) significantly influenced by type of brain lesion; (c) prognostically relevant only in patients studied after the first 3 days after trauma.

Reliability in diagnosis of brain death.

OBJECTIVE: To compare some of the confirmatory investigations of brain death with clinical criteria in order to achieve the most sensitive and accurate diagnosis of brain death. DESIGN: All patients with isolated brain lesions and Glasgow Coma Scale (GCS) = 3 were subjected to neurological examination after ruling out hypothermia, metabolic disorders and drug intoxications and diagnosed as clinically brain-dead when the brainstem reflexes were absent and the apnea test positive. PATIENTS: 15 patients with clinical diagnosis of brain death entered this study. MEASUREMENTS AND RESULTS: The patients were submitted to the following investigations: electroencephalogram (EEG), transcranial Doppler (TCD) of the middle cerebral arteries (MCA), cerebral blood flow measurements with the i.v. Xe-133 method (CBF) and selective cerebral angiography (CA). EEG was isoelectric in 8 patients while the remaining 7 patients showed persistence of electrical activity. TCD was compatible with intracranial circulatory arrest in 18 MCA districts, compatible with normal flow in 2 and undetectable in 10 out of 30 districts insonated. In CBF examinations, however, all the patients showed a characteristic "plateau" of the desaturation curves lasting through the whole investigation and suggestive of absent cortical flow. CA showed circulatory arrest in both carotid and vertebral arteries. CONCLUSIONS: Our study suggests that cerebral angiography and CBF studies are the most reliable investigations whereas the role of EEG and TCD remains to be determined because of the presence of false negatives and positives.

Intermediate intensive units: definition, legislation and need in Italy.

This paper deals with the definition of intensive care medicine and the organization of different levels of care; intermediate and high level. The organization, facilities and personnel for intermediate care are discussed. The available public data on the organization of intensive medicine and modifications planned by the Legislator are considered. Finally, the usefulness of intermediate care and an estimate of the actual need, based on prospective multicentre ad hoc studies, are discussed.

[Energy expenditure during a pregnancy complicated by post-traumatic coma: analysis of 2 clinical cases]. / Spesa energetica in corso di gravidanza complicata da coma post-traumatico: analisi di due casi clinci.

OBJECTIVE: To analyze the measured resting energy expenditure, the clinical evolution and the nutritional therapy of two pregnant women complicated by post-traumatic coma and sepsis. DESIGN: Clinical study. SETTING: The ICU of Neurosurgery in Regional Hospital in Italy. PATIENTS: Two subjects with head trauma due to a motor vehicle accident. METHOD: The resting energy expenditure was measured (M-REE) by indirect calorimetry by oxygen consumption (VO2) and carbon dioxide production (VCO2). Values were controlled in patients with a hemodynamic stability every 4 hours. Predicted REE (P-REE) was calculated according to the Harris-Benedict formula. A total parenteral nutrition (1.2-1.3 x M-REE) composed of dextrose (70-80% of total caloric amount) and fat (20-30%) was infused in both the subjects. As an average 12-15 g of nitrogen were infused daily. RESULTS: VO2 and VCO2 increased during the study (case 1: from 225 +/- 33 to 325 +/- 35 ml/min; p < 0.02; LR: p < 0.0001; VCO2: from 170 +/- 24 to 289 +/- 23 ml/min; p < 0.0001. Case 2: VO2: from 239 +/- 22 to 315 +/- 35 ml/min; p < 0.05; LR: p < 0.01. VCO2 from 177 +/- 31 to 247 +/- 22 ml/min; p < 0.05; LR: p < 0.001). M-REE/kg increased with statistical significance during the study (case 1: from 23.6 +/- 4.1 to 34.1 +/- 4.3, p < 0.05, LR: p < 0.005; case 2: from 23.7 +/- 5.8 to 33.4 +/- 7.7, p < 0.05, LR: p < 0.05). A physiological variation in oxidative capacity on nutritional substrates was reported throughout the study. CONCLUSION: Sepsis and miscarriages following trauma seem to be the cause in an increase of the energy expenditure rather than pregnancy itself. However our observations must be viewed with caution because they are based on a small number of patients.

Cardiac cachexia: preoperative and postoperative nutrition management.

The present study examined the hemodynamic and metabolic effects of nutrition support in patients with malnutrition secondary to severe mitral valve disease and congestive heart failure. Pulmonary artery pressure measurements, echocardiographic studies, gas exchange measurements, immune function tests, and clinical evaluations were made on hospitalized patients 2 weeks before and 3 weeks after surgery for valve replacement or annuloplasty. All patients received a total daily energy intake of 20 to 30 kcal/kg, four of the patients preoperatively as a combination of oral food plus parenteral nutrition and these four patients plus two additional patients as only parenteral nutrition in the early postoperative period. All six patients received nutrition support as oral food plus parenteral nutrition in the late postoperative period. Compared with baseline, nutrition support was associated with stable hemodynamic function, unchanged whole-body oxygen consumption and carbon dioxide production, and improved clinical indices both before and after surgery. Comprehensive hemodynamic, metabolic, and clinical studies thus indicate that acceptable levels of nutrition support can be provided to malnourished patients with severe congestive heart failure, which improves their clinical status and does not adversely influence cardiac function.

Acute renal failure in the patient undergoing cardiac operation. Prevalence, mortality rate, and main risk factors.

A total of 775 consecutive patients who survived the first 24 hours after cardiac operation were prospectively studied to assess the prevalence, mortality rate, and main risk factors for development of new acute renal failure. Normal renal function before operation (serum creatinine level less than 1.5 mg/dl) was registered in 734 (94.7%) patients. Of these, 111 (15.1%) showed a postoperative renal complication including 84 (11.4%) classified as renal dysfunction (serum creatinine level between 1.5 and 2.5 mg/dl) and 27 (3.7%) as acute renal failure (serum creatinine level higher than 2.5 mg/dl). The mortality rate was 0.8% in normal patients, 9.5% in patients with renal dysfunction, and 44.4% when acute renal failure developed (p < 0.0001). Indeed, the renal impairment proved to be an independent predictor of mortality (p < 0.001), along with the infective (p < 0.001), gastrointestinal (p < 0.001), and cardiovascular (p < 0.05) complications. Multivariate analysis identified the following variables as independent risk factors for postoperative renal impairment: use of intraaortic balloon pump (p < 0.0001), need for deep hypothermic circulatory arrest (p < 0.005), low-output syndrome (p < 0.005), advanced age (p < 0.005), need for emergency operation (p < 0.025), and low urinary output during cardiopulmonary bypass (p < 0.05). The 41 patients (5.3%) with preoperative renal failure showed a significantly higher morbidity and mortality rate than those without renal complications before operation. We conclude that in patients undergoing cardiac operation without preexisting renal dysfunction the likelihood of severe renal complications is reasonably low, but the associated mortality remains high. A prominent role in the development of postoperative acute renal failure must be recognized for preoperative, intraoperative, and postoperative hemodynamic factors, whereas cardiopulmonary bypass seems to be of lesser importance in this respect.

[Gastric pH changes during and after extracorporeal circulation. What is its clinical meaning?]. / Variazione del pH gastrico durante e dopo circolazione extracorporea. Quale significato clinico?

OBJECTIVE: To determine the relationship between gastric pH (pHm) and several other indices of blood perfusion in patients undergoing cardiopulmonary bypass (CPB). To evaluate the importance of pHm as a prognostic index for elective cardiac surgery. DESIGN: Prospectives study. SETTING: Cardiac surgery ICU of a Regional Hospital in Italy. PATIENTS: Nineteen patients were sequentially studies in a 4-month period. METHOD: Before anesthetic induction, a pH probe incorporated in the tip of a nasogastric tube (GrapHprobe SH, GrapHometer, Zinetics Medical, USA) was inserted in the stomach. Results, collected during the CPB and in the postoperative period until 1 hour after extubation, were compared to the peripheral tissue perfusion and oxygenation data (transcutaneous: PtcO2), hemodynamic variations (Swan-Ganz catheter), pharyngeal temperature, and blood gases. RESULTS: No significant variations of pHm were reported during the study. Significant relations were found only after surgery between pHm and PaO2 (p < 0.001), hemoglobin (p < 0.001), and blood pH (p < 0.05). No statistical correlations were reported between pHm and hemodynamic variations. CONCLUSIONS: Although a significant variation of peripheral and pulmonary vascular resistance and transcutaneous oxygenation was reported throughout the study, no correlations were found to pHm. At present it is not possible to confirm the importance of pHm as a prognostic index for elective cardiac patients, even though it is necessary to examine whether the additional data of pHm variation could be considered a true marker of visceral perfusion.

The effects of prolonged cardiopulmonary bypass on cell-mediated immunity.

Studies of T-cell subsets (CD3+, CD4+, CD8+, CD8+ CD57+ cells), lymphocyte response to concanavalin A (Con A), phytohaemoagglutinin (PHA) and the alterations of white cell membranes shown by scanning electronic microscope (SEM) in 51 patients who underwent cardiac operation were performed. Out of these 51 unselected patients, for 16, duration of CPB was < or = 110 min (group A), while for the other 35 (group B) it was prolonged (> 110 minutes). Although variations of the lymphocyte subset observed between groups A and B were slightly significant (p < 0.05 before CPB and on postoperative day 7), the T-cell reactivity in group B in comparison to that of group A did not normalize by postoperative day 7 regardless of stimulation with PHA or with Con A. With the use of the SEM, the folded aspect of lymphocyte surface decreased after surgery in about 71% (group A) and 78% (group B) of the observed cells. The outcome of the immunological effects given by our studies could have been due to an elongated CPB even if there need to be taken into consideration multifactorial influences, i.e. biological, pharmacological and hormonal hypotheses, and rapid changes in CPB-micro-environment.

Effects of a continuous diltiazem infusion on renal function during cardiac surgery.

Thirty-five male patients undergoing coronary artery surgery were studied to investigate renal function during a continuous infusion of the calcium channel blocker diltiazem. All patients had preoperative renal function within normal limits (serum creatinine below 0.133 mmol/L) and were randomly divided into three groups: Control (C), Diltiazem 1 (D1), and Diltiazem 2 (D2). Diltiazem was infused in D1 (1 microgram/kg/min) and D2 (2 micrograms/kg/min) patients throughout surgery and during the following 36 hours. Glomerular function was investigated using the endogenous creatinine clearance while tubular function was assessed by means of water and sodium reabsorption tests, as well as urinary enzyme activity measurements. Hemodynamic monitoring was performed using a pulmonary artery catheter. The glomerular filtration rate of C and D1 patients showed a significant fall during cardiopulmonary bypass (CPB) with respect to the prebypass period and returned to the baseline values only in the postoperative period. A similar change was not observed in D2 patients. The analysis of variance demonstrated that the glomerular filtration rate was significantly higher in Group D2 versus Group C during and after CPB (P = 0.03 and P = 0.04, respectively). Furthermore, after CPB, urinary output was significantly improved in D2 patients, both versus C and D1 patients (P = 0.003), notwithstanding a lower mean arterial pressure in the D2 Group (P = 0.04 v C Group). Tubular function was not influenced by diltiazem infusion. It is concluded that a continuous diltiazem infusion, at a dose of 2 micrograms/kg/min during cardiac surgery, may be useful to prevent a decrease in glomerular function secondary to cardiopulmonary bypass.

Total parenteral nutrition in patients with intra-aortic balloon counterpulsation.

The effects of total parenteral nutrition (TPN) were studied in nine of 19 patients with intra-aortic balloon pumping TPN (c. 27 kcal/kg/day) was begun 3 hours after the start of pumping. The non-protein caloric source was composed of hypertonic dextrose and fat emulsion (60% and 40%). The nitrogen intake was 1 g/150-200 kcal/day. The ten control patients received 5% dextrose in corresponding volume/hour. Hemodynamic studies were performed before and 24, 48 and 72 hours after the start of counterpulsation. The predicted and the observed resting energy expenditure were recorded in both patient groups during counter-pulsation. Systemic and pulmonary vascular resistance differed significantly between the groups. Cardiac function improved in both groups. In the TPN group the measured resting energy expenditure increased by 33% more than predicted on day 2 and by 56% on day 3 and in the controls the figures were 31% and 40%--all rises significant. Total parenteral nutrition with low fat content thus alters the hemodynamic equilibrium without clinically significant effects in patients undergoing intra-aortic balloon pumping. These patients are hypermetabolic and should receive artificial nutrition as soon as possible.

Assessing brain function in post-traumatic coma by means of bit-mapped SEPs, BAEPs, CT, SPET and clinical scores. Prognostic implications.

Sixty-eight severely head injured comatose patients were studied. Bit-colour-mapped SEPs to median nerve stimulation, BAEPs, CT and SPET regional values and ICP were assessed in relation to clinical information in evaluating cerebral function. All these variables were related to a 1-year outcome. Statistical tests confirmed the higher predictive reliability of both neurophysiological and perfusive (SPET) functional parameters compared to CT structural findings. Generally, SEPs appeared to be more reliable in predicting outcome than BAEPs. Modifications of frontal components could occur independently of post-central ones, being closely related to underlying cerebral lesions. The parameter showing the greatest correlation with outcome in the first recording session was the P25 latency, whereas this prognostic role was mainly assumed by the amplitude value of the frontal N30-P45 complex in a second recording session carried out during the third week following head trauma.

[Treatment and outcome of prospective organ donors in neurosurgical intensive therapy. Analysis of a 3-year period]. / Trattamento e outcome di potenziali donatori d'organo in terapia intensiva neurochirurgica. Analisi di un triennio.

Strict guidelines for selection, monitoring and treatment of Potential Organ Donors (POD) in Neurosurgical Intensive Care Units (ICUs) are mandatory since patients with Acute Brain Injuries (ABI) are more frequently admitted on these specialized ICUs. We report the guidelines accepted in the Neurosurgical ICU of Treviso City Hospital (TVH) and the results obtained in the last three years (1988-1990). All patients with unfavourable neurological outcome were considered POD if absolute or relative contraindications to organ procurement were absent. They were treated with a multisystemic approach, according to standard protocols, including: ECG monitoring, water and electrolyte balance restoration, pharmacological cardiocirculatory support, prophylaxis and treatment of infections, control of hormonal disturbances. Our data demonstrate an increase of POD from TVH due to the centralization of patients with ABI in the Neurosurgical ICU and show an increase of the rate of POD from Neurosurgical ICU vs General ICU of TVH. The increase of POD in the Neurosurgical ICUs involves medical, legal, organizing and psychological problems, related to this clinical condition. The attention to severe protocols, that must be periodically reviewed, makes more easy the management of POD and ameliorates the outcome of these patients.

Case report acute respiratory failure after posterior cranial fossa surgery: report of two cases with unusual etiology.

Acute respiratory failure (ARF) occurred in two patients who had normal preoperative findings and intraoperative courses, early after posterior cranial fossa (PCF) surgery. In both instances, the postoperative pulmonary failure appeared to be due to an unknown pulmonary cancer, revealed by autopsy. The diagnosis of an asymptomatic pulmonary malignancy might be considered in the presence of ARF of unclear etiology in patients who undergo PCF surgery for removal of a brain tumor.

Successful cardiopulmonary resuscitation using high doses of epinephrine.

Cardiac arrest usually carries a bleak prognosis when occurring in patients who have undergone open heart surgery. We report two cases where cardiac arrest was not responsive to routine therapies. Doses of epinephrine 5-10 times higher than recommended were able to provide a resolution, and the patients were discharged in a normal neurological state.