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Biomedical subjects

A Candiani

Publications and source records attributed to A Candiani.

At least 19 recordsLinked to original sources
PubMed2005

Antibiotic prophylaxis of early onset pneumonia in critically ill comatose patients. A randomized study.

OBJECTIVE: To evaluate if a 3-day ampicillin-sulbactam prophylaxis can reduce the occurrence of early-onset pneumonia (EOP) in comatose mechanically-ventilated patients. DESIGN: This was a single-centre, prospective, randomised, open study. SETTING: A 10-bed general-neurological ICU in a 2,000-bed university hospital. PATIENTS AND PARTICIPANTS: Comatose mechanically-ventilated patients with traumatic, surgical or medical brain injury. INTERVENTIONS: Patients were randomized to either ampicillin-sulbactam prophylaxis (3 g every 6 h for 3 days) plus standard treatment or standard treatment alone. MEASUREMENTS AND RESULTS: Main outcome was the occurrence of EOP. Secondary outcome measures were occurrence of late-onset pneumonia, percentage of non-pulmonary infections and of emerging multiresistant bacteria, duration of mechanical ventilation and of ICU stay and ICU mortality. Interim analysis at 1 year demonstrated a statistically significant reduction of EOP in the ampicillin-sulbactam group, and the study was interrupted. Overall, 39.5% of the patients developed EOP, 57.9% in the standard treatment group and 21.0% in the ampicillin-sulbactam group (chi-square 5.3971; P =0.022). Relative risk reduction of EOP in patients receiving ampicillin-sulbactam prophylaxis was 64%; the number of patients to be treated to avoid one episode of EOP was three. No differences in other outcome parameters were found; however, the small sample size precluded a definite analysis. CONCLUSIONS: Antibiotic prophylaxis with ampicillin-sulbactam significantly reduced the occurrence of EOP in critically ill comatose mechanically ventilated patients. This result should encourage a large multicenter trial to demonstrate whether ampicillin-sulbactam prophylaxis reduces patient mortality, and whether antibiotic resistance is increased in patients receiving prophylaxis.

Adult↗
PubMed2005

Effect of tidal volume and respiratory rate on the power of breathing calculation.

BACKGROUND: The power of breathing (PoB) is used to estimate the mechanical workload of the respiratory system. Aim of this study was to investigate the effect of different tidal volume-respiratory rate combinations on the PoB when the elastic load is constant. In order to assure strict control of the experimental conditions, the PoB was calculated on an airway pressure-volume curve in mechanically ventilated patients. METHODS: Ten patients received three different tidal volume-respiratory rate combinations while minute ventilation was constant. Respiratory mechanics, PoB and its elastic and resistive components were calculated. Alternative methods to estimate the elastic workload were assessed: elastic work of breathing per litre per minute, elastic workload index (the square root of elastic work of breathing multiplied by respiratory rate) and elastic double product of the respiratory system (the elastic pressure multiplied by respiratory rate). RESULTS: Despite constant elastance and minute ventilation, the elastic PoB showed an increment greater than 200% from the lower to the greater tidal volume, accounting for approximately 80% of the whole PoB increment. On the contrary, elastic work of breathing per litre per minute, elastic workload index and elastic double product did not change. CONCLUSION: Changes in breathing pattern markedly affect the PoB despite constant mechanical load. Other indexes could assess the elastic workload without tidal volume dependence. Power of breathing use should be avoided to compare different mechanical loads or efficiencies of the respiratory muscles when tidal volume is variable.

Aged↗
PubMed2004

Effect of breathing pattern on the pressure-time product calculation.

BACKGROUND: The pressure-time product (PTP) is often used to compare conditions with different breathing patterns. Being the pressure-time product calculated with pressures changes over a minute, mechanical load and inspiration time per minute should be its main determinants. The aim of this study was to investigate if the method of PTP computation is affected by the breathing pattern when mechanical load and inspiratory time per minute are constant. METHODS: Respiratory mechanics and the PTP developed by the ventilator were calculated in 10 mechanically ventilated patients at three different respiratory rate/tidal volume combinations, provided that minute ventilation and inspiratory time per minute were constant. RESULTS: The static elastance did not change at different tidal volumes. Despite the constant elastic load over a minute, the elastic PTP showed an increment greater than 200% from the higher to the lower respiratory rate, responsible for approximately 80% of the whole PTP increment. On the contrary a 'corrected' elastic PTP (calculated using the square root of the elastic pressure-time area), the elastic double product of the respiratory system and the mean elastic pressure per minute, did not significantly change. CONCLUSIONS: Changes in breathing pattern markedly affected the PTP independently by the mechanical load and the inspiratory time per minute. In these conditions it could not correctly estimate the metabolic cost of breathing. The use of a 'corrected' PTP, the mean inspiratory pressure per minute or the double product of the respiratory system, could overcome this limitation.

Aged↗
PubMed2003

Bedside burr hole for intracranial pressure monitoring performed by anaesthetist-intensive care physicians. Extending the practice to the entire ICU team.

BACKGROUND: To evaluate the effects of extending the practice of bedside burr hole for intracranial pressure (ICP) monitoring to the entire ICU team. METHODS DESIGN: a 10-year observational cohort study. SETTING: A general-neurologic 12-bed ICU of a University Hospital with 10 full-time specialists in anaesthesia-intensive care. PATIENTS: patients admitted for acute neurologic lesions requiring ICP monitoring. MEASUREMENTS: ICP monitoring was performed by means of intraparenchymal fiberoptic cathe-ters. Rates of successfully performed procedures and complications were compared between 2 study periods: January 1990 - August 1997, in which the procedure was performed by 2 experienced physicians (group 1), and September 1997-July 2000 in which the procedure was extended to the entire team (group 2). RESULTS: Two hundred and seventy patients had 293 catheters positioned (group 1=180; 2=113). The procedure was successfully performed in all cases. Occurrence of complications was similar in the 2 groups: minor surgical wound infections (3.3%; 2.6%); meningitis (0.5%; 0); scalp (3.9%; 2.6%) and dural (5.0%; 6.2%) bleeding; intracranial haematoma (1.1%; 1.8%). Two of these latter (1 for each group) required surgical evacuation. Twelve anaesthetist-intensive care physicians were trained, and they were able to perform burr hole for ICP monitoring without help after 2-3 assisted procedures. CONCLUSIONS: Extending the practice of ICP monitoring to the entire ICU team is safe and feasible. To decide whether or not to implement this technique, one should consider the high costs on one side and prompt availability of ICP monitoring on the other. Haemorrhagic and infectious complications are comparable to those of neurosurgical series.

Catheterization↗
PubMed2001

Acute respiratory acidosis does not increase plasma potassium in normokalaemic anaesthetized patients. A controlled randomized trial.

BACKGROUND AND OBJECTIVE: Few and conflicting data are available regarding the changes of plasma potassium concentration during acute respiratory acidosis in human beings. This study compares the acute changes in plasma potassium concentration in acutely hypercapnic patients and in non-hypercapnic patients during general anaesthesia. METHODS: Thirty-three patients undergoing interventional rigid bronchoscopy were studied. Ventilation of the lungs was randomly conducted using either spontaneous-assisted ventilation or intermittent negative-pressure ventilation. All patients received the same anaesthetic protocol. Arterial blood gases and osmolality, and plasma concentrations of glucose, sodium, potassium and chloride were measured. RESULTS: Intraoperatively, PaCO2 was higher during spontaneous-assisted ventilation than during intermittent negative-pressure ventilation (9 +/- 1.8 vs. 5.4 +/- 1.2 kPa, P < 0.001) and the pH was also lower during spontaneous-assisted ventilation than during intermittent negative-pressure ventilation (7.24 +/- 0.07 vs. 7.4 +/- 0.08, P < 0.001). Plasma potassium concentration remained similar in both groups (3.8 +/- 0.2 mmol L(-1) with spontaneous-assisted ventilation vs. 3.7 +/- 0.4 mmol L(-1) with intermittent negative-pressure ventilation). CONCLUSION: Acute respiratory acidosis does not affect plasma potassium concentration.

Acidosis, Respiratory↗
PubMed2001

Pulmonary microvascular and perivascular interstitial geometry during development of mild hydraulic edema.

To study pulmonary arteriolar vasomotion in control conditions and in the transition to hydraulic edema, changes in subpleural pulmonary arteriolar diameter and perivascular interstitial volume were evaluated in anesthetized spontaneously breathing rabbits. Images of subpleural pulmonary microvessels were recorded in control conditions and for up to 180 min during a 0.5 ml x kg(-1) x min(-1) intravenous saline infusion through an intact parietal pleural window. Images were digitized and analyzed with a semiautomatic procedure to determine vessel diameter and perivascular interstitial thickness from which interstitial fluid volume was derived. In control vessels, the diameter of approximately 30-, approximately 50-, and approximately 80-microm arterioles and the perivascular interstitial thickness were fairly stable. During infusion, the diameter increased maximally by 20% in approximately 30 microm vessels, was unchanged in approximately 50 microm vessels, and decreased by 25% in approximately 80-microm arterioles; the perivascular interstitial volume increased by 54% only around 30-microm microvessels. In papaverine-treated rabbits, all arterioles dilated and a larger increase in perivascular interstitial thickness was observed. The data suggest that the opposite vasomotor behavior of 30- and 80-microm arterioles during development of mild edema may represent a local specific response of the pulmonary microcirculation to reduce capillary pressure in the face of an increased transendothelial fluid filtration, thus counteracting progression toward severe edema.

Animals↗
PubMed2000

Limits of intermittent jugular bulb oxygen saturation monitoring in the management of severe head trauma patients.

OBJECTIVE: To evaluate, in a prospective, observational study, whether bilateral monitoring of jugular bulb oxyhemoglobin saturation (SjO2), in addition to standard monitoring, results in modification of the management of severe head trauma. METHODS: The patients underwent bilateral jugular bulb cannulation and observation at 8-hour intervals, during which SjO2 was measured and the neurological condition and physiological variables were assessed. The study group was responsible for evaluating whether the physician's decision-making process was influenced by the detection of SjO2 abnormalities. The SjO2 discrepancy in simultaneous bilateral samples was also evaluated to determine whether it interfered with the interpretation of data and with clinical decision-making. The SjO2-related complications were monitored. RESULTS: Thirty patients underwent 319 observations. In 96% of patients, SjO2 was normal or high and had no influence on the diagnostic or therapeutic strategies. Treatment decisions were dictated by changes in clinical status and in intracranial and cerebral perfusion pressure. When these parameters were abnormal, treatment was administered, even if SjO2 was normal (101 observations). Conversely, when SjO2 was the only detected abnormality (34 observations), no treatment was administered. Abnormally low SjO2 values, caused by hypovolemia and hypocapnia, were detected in 3.4% of observations and actually modified the management. The discrepancies in simultaneous bilateral samples were substantial and gave rise to relevant interpretation problems. Fifteen percent of jugular catheters showed evidence of bacterial colonization. CONCLUSION: Intermittent SjO2 monitoring did not substantially influence the management of severe head trauma. Therefore, recommendation for its routine use in all patients seems inadvisable, and indications for this invasive method should no longer be defined on the basis of experts' opinions, but rather on randomized, prospective studies.

Adolescent↗
PubMed2000

Negative pressure ventilation vs external high-frequency oscillation during rigid bronchoscopy. A controlled randomized trial.

STUDY OBJECTIVES: To compare the effectiveness of two modalities of external ventilation during rigid bronchoscopy: intermittent negative pressure ventilation (INPV) and external high-frequency oscillation (EHFO). DESIGN: Prospective, controlled, randomized, nonblinded study. SETTING: University-affiliated hospital. PATIENTS: Seventy patients undergoing interventional rigid bronchoscopy for tracheobronchial lesions were enrolled into the study. INTERVENTIONS: Mechanical ventilation was performed by INPV or EHFO. When pulse oximetry was < 90%, manually assisted ventilation was delivered. MEASUREMENTS AND RESULTS: Arterial blood gases were sampled preoperatively and intraoperatively. Most patients in both groups had normal intraoperative PaCO(2) (mean, 43. 6 +/- 11.8 mm Hg under EHFO and 37.4 +/- 8.2 mm Hg under INPV; p = 0.012), and acidemia occurred in 9 of 35 patients of EHFO group and in 2 of 35 patients of INPV group (p = 0.049). Hypercapnia (PaCO(2) > 50 mm Hg) was observed in 10 patients under EHFO and in 2 with INPV (p = 0.026). Intraoperative mean PaO(2) was similar (101.4 +/- 52.9 mm Hg with EHFO and 124.2 +/- 50.3 mm Hg with INPV; p = 0.07), but O(2) supply was different (3.5 +/- 2.3 L/min during INPV and 8.5 +/- 6.2 L/min during EHFO; p < 0.001). Intraoperative hypoxemia (PaO(2) < 60 mm Hg) occurred in five patients with EHFO and two with INPV (p = 0.426). Three EHFO patients required manually assisted ventilation (mean, 0.2 +/- 0.9), but no INPV patient did (p = 0.142). CONCLUSIONS: External negative pressure ventilation appears to be a suitable choice during rigid bronchoscopy: both EHFO and INPV ensure effective ventilation and comfortable operating conditions in the majority of patients. Some patients may receive inadequate ventilation with EHFO, developing respiratory acidosis and requiring manually assisted ventilation. In comparison with INPV, EHFO requires a higher fraction of inspired oxygen.

Adult↗
PubMed2000

[Systemic and pulmonary vascular resistance in brain death].

BACKGROUND: Hemodynamic instability is known to affect brain dead subjects and it can be dangerous for the viability of transplantable organs. Aim of the present study was to assess the hemodynamic performance in brain dead subjects, the changes during the legal observation period and the results of therapeutic management. METHODS: The authors evaluated 28 consecutive adult brain dead subjects, all in intensive treatment, controlled ventilation, infusion therapy and/or dopamine administration and continuous direct monitoring of arterial pressure. Ten hemodynamic parameters have been registered by the thermodilution method and the Swann-Ganz catheter. The Legal Committee performed measurements at the beginning (T0) and the end (T6) of the observation period, which lasts 6 hours according to the current law on death certification (Law N. 578/93). RESULTS: Low systemic and pulmonary vascular resistances have been documented in the majority of subjects (75%), both treated only with fluids and with the additional dopamine administration (dosage lower than 10 ug/Kg/min). The above-mentioned reduction was similar at the two different monitored times (T0 and T6). CONCLUSIONS: This situation can be ascribed to the destruction of the cerebral vasoactive centers and the consequent hypotension is due to autonomic nervous system dysfunction. Hemodynamic instability must be treated by fluids and inotropic drugs, but they may cause cardiac and respiratory problems, thus it is suggested to use also low doses of vasoconstrictive drugs, provided that cardiac condition allows this therapeutic strategy.

Adolescent↗
PubMed2000

[Approach to the patient in vegetative state. Part I: diagnosis].

Coma is the condition in which both components of consciousness, wakefulness and awareness, are lost. Therefore, the comatose patient neither opens the eyes, nor utters comprehensible words or follows commands. In the vegetative state (VS), awareness (including all cognitive function and emotion) is lost, while the vegetative functions, including breathing and sleep-wake cycles (the wakefulness), persist. Usually VS follows a state of coma caused by traumatic or anoxic brain damage. Pathologic brain examination demonstrates extensive subcortical, white matter, bilateral thalamic, and brainstem lesions in various combinations. Bilateral cerebral cortical lesions are rare, and therefore cortex can be "out of action" despite unaltered structure. More rarely, VS is caused by brain developmental malformations in children, or metabolic or degenerative diseases in children and adults. These are the only cases in which patients are not comatose before VS becomes apparent. After 6-8 weeks of coma, patients regain the eye opening. In such a condition, the term coma is no longer appropriate. If awareness is absent, the patient can be defined as in VS. Finally, the VS is defined as persistent (PVS) when it has continued for at least 1 month. The diagnosis of VS and PVS are clinical and require assessment over an adequate period of time and the skills of a multidisciplinary experienced team. Diagnosis is very complex in infants younger than 3 months, and is not applicable to preterm neonates, with the unique exception of infants with anencephaly. Among ancillary diagnostic tools, dynamic PET studies show promise.

Adult↗
PubMed2000

[Approach to the patient in vegetative state. Part II: differential diagnosis].

A prerequisite to the diagnosis of vegetative state is the exclusion of apparently similar syndromes, in which the patient retains the consciousness partially or even completely. Some syndromes are not separate nosological entities and should be abandoned: the apallic state, the neocortical death, the decerebrate and decorticate state, the alpha-coma, the vigil or prolonged or irreversible coma are among them. Three conditions deserve special consideration. The term locked-in syndrome describes a patient completely paralysed and mute, but fully conscious, and is usually caused by ischemic lesions of the pons. Several variants do exist, either in the causes and site of lesion. Some patients may become paralysed and mute, but conscious because of polyneuropathies, that is in the absence of any lesions of the central nervous system. The akinetic mutism is a rare condition characterised by loss of speech and nearly absent bodily movements. Painful stimulation may cause appropriate withdrawing, and wakefulness and self-awareness may be preserved, but cognitive impairment is usually present. It must be emphasised that this condition can be due to potentially treatable lesions, such as hydrocephalus and craniopharyngioma. The term "minimally responsive" or "minimally conscious" describes severely disabled patients in whom meaningful responses can be demonstrated, although inconstantly. This condition, the true diagnostic challenge, often represents a transition phase of vegetative patients recovering consciousness. Physicians, physiotherapists and patient's relatives should work all together to reach a correct diagnosis, by using current available methods to monitorize the recovery of consciousness.

Diagnosis, Differential↗
PubMed2000

[Approach to the patient in vegetative state. Part III: prognosis].

To define a vegetative state (VS) as permanent is to declare its irreversibility. In 1994 a North-American multidisciplinary task force, by extensively analysing the literature, concluded that the recovery of consciousness from a post-traumatic or non-traumatic VS is unlikely after 12 and 3 months respectively. These conclusions did not obtain unanimous consent. The term permanent was in fact inappropriately used to define either the loss of consciousness or of function. Furthermore, patients with traumatic brain injury have been shown to recover the consciousness in a substantial greater percentage (6-7%) than previously appreciated (1.6%). This is hardly compatible with the peremptoriness of the term permanent, which should be used only in case of certainty. Ancillary tests are important in defining the prognosis. Patients in deep coma after an anoxic brain injury can be predicted as having a poor prognosis (death or permanent VS) with 100% specificity within one week of the insult. Magnetic resonance of the brain can predict patients at high risk of permanent VS within 6-8 weeks of a traumatic brain injury. In conclusion, the available evidence does not permit to define with certainty the patients who have irremediably lost their consciousness after a devasting brain insult. However, it seems possible to reliably define the risk of severe disability. Whether or not this knowledge might or should be used to titrate the intensity of therapeutic approach is to be defined. In this respect, it is central the definition of what an "acceptable outcome" is, certainly not an exclusive medical attribution.

Humans↗
PubMed1999

Acute neuromuscular respiratory failure after ICU discharge. Report of five patients.

OBJECTIVE: To describe a syndrome of acute neuromuscular respiratory failure (NM-ARF) caused by ICU-acquired acute myopathy and neuropathy. DESIGN: Case series. SETTING: General Regional University Hospital in Brescia, Italy. PATIENTS: Five adult patients with NM-ARF after prolonged ICU stay and successful weaning from the ventilator and ICU discharge. INTERVENTIONS: None. MEASUREMENTS: Clinical signs of NM-ARF, electroneurography and electromyography (ENMG) of peripheral nerves and muscles, and functional assessment of respiratory muscles. RESULTS: NM-ARF was diagnosed at the time of (one case), or 1-3 days after, ICU discharge. Limb weakness alarmed the physicians, while the signs of the NM-ARF were initially undetected. In the first observed case the acute respiratory failure was near fatal, and necessitated ICU readmission, while in the other cases 2 weeks of aggressive chest physiotherapy permitted resolution of the respiratory failure. History, clinical course and ENMG indicated the diagnosis of critical illness myopathy and neuropathy (CRIMYNE). Three patients recovered fully, while two had persisting evidence of axonal polyneuropathy several months after the onset. CONCLUSIONS: Critically ill patients with prolonged ICU stay, sepsis and MOF are at great risk of developing CRIMYNE, which in turn may be responsible for NM-ARF. This latter complication may arise after resolution of the respiratory and cardiac dysfunctions and successful weaning from the ventilator. As NM-ARF may cause unplanned ICU readmission or even unexpected death, strict clinical surveillance and monitoring of respiratory muscle function is recommended after discharge to the general ward of patients with proven NM-ARF. Early intensive chest physiotherapy can resolve the condition.

Adult↗
PubMed1999

Work of breathing-tidal volume relationship: analysis on an in vitro model and clinical implications.

OBJECTIVE: Work of breathing (WoB) is currently employed to assess the afterload on the respiratory muscles and to estimate the energy expenditure for breathing. Since WoB depends on the ventilated tidal volume (TV), WoB*L(-1), the indicized form of WoB has been employed as a measure of WoB which is independent of TV. Actually, the independence of WoB*L(-1) from the ventilated TV has never been demonstrated. The aim of this study was to verify the predicted TV-independence of WoB*L(-1) on an in vitro model. METHODS: Our experimental model was constituted as follows: two endotracheal tubes, with internal diameter measuring respectively 6.5 and 8.5 mm, were alternatively connected with two rubber balloons whose compliance was respectively 0.02 and 0.06 L/hPa; the system was mechanically ventilated at ten different tidal volumes, ranging from 0.3-1 l. Flow rate was kept constant (35 l/m) during the whole experiment. RESULTS: Both elastic components of the model showed a static volume-pressure relationship which was linear in the experimental range of TV. In all combinations of resistance and compliance WoB increased quadratically whereas WoB*L(-1) increased linearly with the growing TV (p < 0.001). CONCLUSIONS: These results demonstrate the TV-dependence of WoB*L(-1) and suggest that WoB*L(-1), if TV changes, cannot be considered as an index of respiratory muscle afterload and should not be used as a guide for weaning patients from the mechanical ventilation. Finally, we introduced a new parameter (WoB1L) which seems to be a more TV-independent measure of respiratory work.

Humans↗
PubMed1999

Remifentanil vs. fentanyl during interventional rigid bronchoscopy under general anaesthesia and spontaneous assisted ventilation.

The treatment of tracheo-bronchial diseases with rigid bronchoscopy requires general anaesthesia without tracheal intubation. Spontaneous assisted ventilation is a safe modality of ventilation. In this study the use of remifentanil and fentanyl is compared during rigid bronchoscopy with spontaneous assisted ventilation. Ninety high-risk patients received fentanyl or remifentanil with propofol for general anaesthesia. During the maintenance fentanyl was delivered at 6.1 +/- 4.6 micrograms kg-1 h-1 and remifentanil at 0.15 +/- 0.07 microgram kg-1 min-1. The same degree of intra-operative respiratory acidosis with similar good operating conditions resulted in both groups. Patients treated with remifentanil recovered more quickly compared with those in the fentanyl group (3.8 +/- 2 vs. 10.4 +/- 9.2 min, P < 0.001). In conclusion, the use of remifentanil during rigid bronchoscopy under general anaesthesia with spontaneous assisted ventilation is safe and assures good operating conditions. Moreover, remifentanil permits a more rapid recovery than fentanyl. The dose of remifentanil is higher than previously described for spontaneously breathing patients.

Anesthesia, General↗