Computer based haemodynamic guidance system is effective and safe in management of postoperative cardiac surgery patients.

A circulatory guidance system, Navigator, was evaluated in a prospective, randomised control trial at six Australian university teaching hospitals involving 112 scheduled postoperative cardiac surgical patients with pulmonary artery catheters placed and receiving 1:1 nursing care. The guidance system was used to achieve and maintain physician-designated cardiac output and mean arterial pressure targets and compared these with standard post open-heart surgery care. The primary efficacy endpoint was the standardised unsigned error between the targeted and the actual values for cardiac output and mean arterial pressure, time averaged over the duration of cardiac output monitoring - the average standardised distance. This was 1.71 (SD=0.65) for the guidance group and 1.92 (SD=0.65) in the control group (P=0.202). Rates of postoperative atrial fibrillation, adverse events, intensive care unit and hospital length-of-stay were similar in both groups. There were no device-related adverse events. Guided haemodynamic therapy with the Navigator device was non-inferior to standard intensive care unit therapy. The study was registered with ClinicalTrials.gov Identifier NCT00468247.

Acute subdural haematoma in the presence of an intrathecal catheter placed for the prevention of post-dural puncture headache.

A 31-year-old term primigravid woman had an intrathecal catheter placed following a dural puncture during attempted epidural analgesia during labour. After 23 hours she developed sudden loss of consciousness and an urgent brain computed tomography scan demonstrated a large left hyper-acute subdural haematoma. Craniotomy revealed active bleeding from a ruptured left temporal bridging vein. She was extubated 12 hours after surgery and was discharged home 11 days later without neurological deficit. Although subdural haematoma is a recognised complication of dural puncture, it has not been reported in the presence of an intrathecal catheter. An intrathecal catheter may not always prevent cerebrospinal fluid efflux, so subdural haematoma remains a potential complication of inadvertent dural puncture.

Tirofiban and activated protein C synergistically inhibit the Instant Blood Mediated Inflammatory Reaction (IBMIR) from allogeneic islet cells exposure to human blood.

Instant blood mediated inflammatory reaction (IBMIR) occurs when islets are exposed to blood and manifests clinically as portal vein thrombosis and graft failure. The aim of this study was to determine the impact of recombinant human activated protein C (rhAPC) and platelet inhibition on IBMIR in order to develop a better targeted treatment for this condition. Five thousand human islet cell equivalents (IEQ) were mixed in a PVC loop system with 7 mL of ABO compatible human blood and incubated with rhAPC, either alone or in combination with tirofiban. Admixing human islets and blood caused rapid clot formation, consumption of platelets, leukocytes, fibrinogen, coagulation factors and raised d-dimers. Islets were encased in a fibrin and platelet clot heavily infiltrated with neutrophils. Tirofiban monotherapy was ineffective, whereas rhAPC monotherapy prevented IBMIR in a dose-dependent manner, preserving islet integrity while maintaining platelet and leukocyte counts, fibrinogen and coagulation factor levels, and reducing d-dimer formation. The combination of tirofiban and low-dose rhAPC inhibited IBMIR synergistically with an efficacy equal to high dose rhAPC. Tirofiban and rhAPC worked synergistically to preserve islets, suggesting that co-inhibition of the platelet and coagulation pathways' contribution to thrombin generation is required for the optimal anti-IBMIR effect.

Cerebral vasomotor reactivity testing in head injury: the link between pressure and flow.

BACKGROUND: It has been suggested that a moving correlation index between mean arterial blood pressure and intracranial pressure, called PRx, can be used to monitor and quantify cerebral vasomotor reactivity in patients with head injury. OBJECTIVES: To validate this index and study its relation with cerebral blood flow velocity and cerebral autoregulation; and to identify variables associated with impairment or preservation of cerebral vasomotor reactivity. METHODS: The PRx was validated in a prospective study of 40 head injured patients. A PRx value of less than 0.3 indicates intact cerebral vasomotor reactivity, and a value of more than 0.3, impaired reactivity. Arterial blood pressure, intracranial pressure, mean cerebral perfusion pressure, and cerebral blood flow velocity, measured bilaterally with transcranial Doppler ultrasound, were recorded. Dynamic cerebrovascular autoregulation was measured using a moving correlation coefficient between arterial blood pressure and cerebral blood flow velocity, the Mx, for each cerebral hemisphere. All variables were compared in patients with intact and impaired cerebral vasomotor reactivity. RESULTS: No correlation between arterial blood pressure or cerebral perfusion pressure and cerebral blood flow velocity was seen in 19 patients with intact cerebral vasomotor reactivity. In contrast, the correlation between these variables was significant in 21 patients with impaired cerebral vasomotor reactivity, whose cerebral autoregulation was reduced. There was no correlation with intracranial pressure, arterial blood pressure, cerebral perfusion pressure, or interhemispheric cerebral autoregulation differences, but the values for these indices were largely within normal limits. CONCLUSIONS: The PRx is valid for monitoring and quantifying cerebral vasomotor reactivity in patients with head injury. This intracranial pressure based index reflects changes in cerebral blood flow and cerebral autoregulatory capacity, suggesting a close link between blood flow and intracranial pressure in head injured patients. This explains why increases in arterial blood pressure and cerebral perfusion pressure may be useful for reducing intracranial pressure in selected head injured patients (those with intact cerebral vasomotor reactivity).

Non-bronchoscopic bronchoalveolar lavage in the microbiological diagnosis of pneumonia in mechanically ventilated patients.

A prospective study comparing standardized non-bronchoscopic bronchoalveolar lavage (sNB-BAL) and non-specific endotracheal aspirate (NsETA) in the microbiological diagnosis of pneumonia in mechanically ventilated patients is described. One hundred episodes in 82 mechanically ventilated patients with or without radiological and clinical diagnostic criteria of pneumonia were studied. NsETA and sNB-BAL was performed on the day of study. Fifty-one patients had pneumonia (21 ventilator-associated, 12 hospital-acquired, 18 community-acquired) and 49 had no pneumonia as defined by widely accepted clinico-radiological criteria. The sNB-BAL was found to be significantly more specific (0. 73) compared to NsETA (0.35) for the microbiological diagnosis of pneumonia. Colonization rates with NsETA were significantly higher compared to sNB-BAL (P value <0.0001). No patient had complications attributable to the sNB-BAL procedure. We conlude that sNB-BAL is a safe, effective, sensitive, specific and inexpensive procedure for the serial evaluation of pneumonia in mechanically ventilated patients.

Acute renal failure in critically ill patients: evaluation of an ultrasound contrast agent.

The purpose of the present paper was to evaluate an ultrasound contrast agent (Levovist) in patients with oliguric acute renal failure (ARF) in order to assess renal vascularity, differentiate acute tubular from cortical necrosis and predict prognosis. Ten intensive care unit (ICU) patients with oliguric ARF were prospectively investigated by ultrasound including colour, power and pulsed Doppler before and after injection of Levovist. Doppler signals were graded as absent, equivocal or present from the inner and outer portions of the renal parenchyma, and these findings were correlated with clinical parameters and outcome. Only one patient had findings in keeping with acute cortical necrosis. All patients who survived had parenchymal vascularity while only three of six (50%) who died had parenchymal vascularity after Levovist. The ultrasound contrast caused no side effects and additional information was provided which improved diagnostic confidence, enabled appropriate classification of patients as having tubular or cortical necrosis and therefore added prognostic information.

Cardiorespiratory effects of manually compressing the rib cage during tidal expiration in mechanically ventilated patients recovering from acute severe asthma.

OBJECTIVES: To determine the cardiorespiratory effects of manual expiratory rib cage compression in mechanically ventilated patients recovering from acute severe asthma; and to extrapolate these findings to emergency asthma management where ventilation cannot be achieved by positive-pressure ventilation. DESIGN: A prospective, clinical study. SETTING: Intensive care unit. PATIENTS: Four intubated, mechanically ventilated (volume-controlled), adult patients recovering from acute severe asthma. INTERVENTIONS: Patients were studied before, during, and after a 2- to 3-min period of manual compressions applied bilaterally over the lower rib cage (ribs 8 to 10) during consecutive tidal expirations. MEASUREMENTS AND MAIN RESULTS: Air flow (pneumotachograph), airway pressure, radial or brachial arterial pressure, and the hand pressure applied to the patient's rib cage were monitored and recorded on magnetic tape. Playback of the recorded data enabled measurement of changes in lung volume (air flow integration). Changes during rib cage compression consisted chiefly of small decreases in lung volume and peak inspiratory airway pressure that were only observed in the least obstructed patient and were fully reversed after the cessation of compressions. Air flow-time and air flow-volume plots demonstrated expiratory air flow limitation during essentially the entire tidal expiration in each patient, except the least obstructed patient. CONCLUSION: The results suggest that manual compression of the rib cage during consecutive tidal expirations would be ineffective in reducing pulmonary hyperinflation during the emergency management of asthma when air flow obstruction is so severe that ventilation cannot be achieved by positive-pressure ventilation.

[Evaluation of treatment outcome in patients after extremely severe head injury (GCS 3-4)]. / Ocena wyników leczenia pacjentów ze szczególnie ciezkimi urazami czaszkowo-mózgowymi (GCS 3-4).

Advances in the diagnosis and treatment of severe head injured patients (GCS < = 8) have led to major improvement in outcome, but have not eliminated high mortality rates, which range between 38 and 80% as reported in the literature. The aim of this study was to evaluate the outcome of patients with GCS 3 and 4 and to evaluate the role of early and late hypotension (systolic blood pressure SBP < 90 mmHg) in outcome. Sixty two patients with severe head injury were divided into two groups. In Group I-22 patients with GCS 3-4, and in Group II-40 patients with GCS 5-8. There was no significant difference between mortality (p = 0.5), poor outcome (p = 0.36), and the very best outcome in the groups (p = 0.06). There was a statistically significant difference in death rate (p = 0.0012), when hypotension was present at the scene. Our data suggest that patients with extremely severe head injury do not necessarily have a worse outcome, if prompt diagnosis and appropriate aggressive treatment is implemented.

Cardiorespiratory consequences of expiratory chest wall compression during mechanical ventilation and severe hyperinflation.

OBJECTIVES: To measure and compare the effects of manual expiratory compression of either the rib cage or abdomen on cardiac output, end-expiratory lung volume, and other cardiorespiratory variables in an animal model that mimics the severe pulmonary hyperinflation and hemodynamic impairment occurring in patients with severe acute asthma during mechanical ventilation. DESIGN: Prospective, randomized, crossover trial. SETTING: Research laboratory. SUBJECTS: Seven cross-bred, anesthetized, supine dogs. INTERVENTIONS: The following sequence was employed: a) spontaneous breathing without pulmonary hyperinflation; b) positive-pressure ventilation with severe pulmonary hyperinflation (produced by an external variable expiratory flow resistor); c) approximately 7 mins of manual expiratory compression of either the rib cage or abdomen during positive-pressure ventilation-hyperinflation. This sequence was then repeated, incorporating the alternative type of expiratory compression. MEASUREMENTS AND MAIN RESULTS: Cardiac output (measured by thermodilution), aortic pressure, pleural (esophageal) pressure, and changes in end-expiratory lung volume were measured. The decrease in cardiac output due to mechanical ventilation with pulmonary hyperinflation was exacerbated by rib cage compression (p < .001; spontaneous breathing 2.9 +/- 0.2 L/min, hyperinflation 1.5 +/- 0.1 L/min, and rib cage compression 1.0 +/- 0.1 [SEM] L/min). However, the positive-pressure ventilation-hyperinflation-induced decrease in cardiac output was attenuated by abdominal compression (p < .001; spontaneous breathing 3.3 +/- 0.2 L/min, hyperinflation 1.4 +/- 0.1 L/min, and abdominal compression 2.1 +/- 0.1 L/min). Mean aortic pressure returned to prehyperinflation levels during abdominal compression (p < .001; spontaneous breathing 126 +/- 2 mm Hg, hyperinflation 75 +/- 5 mm Hg, and abdominal compression 120 +/- 3 mm Hg). Both types of compression were similarly effective (p > .75) in increasing mean expiratory pleural pressure, so that end-expiratory lung volume was similarly (p > .25) reduced (0.45 +/- 0.05 and 0.40 +/- 0.05 L for rib cage and abdominal compressions, respectively) in this non-air flow, limiting animal model. CONCLUSIONS: The cardiorespiratory effects of manually compressing the rib cage or abdomen during expiration in this animal study suggest that these techniques should be carefully evaluated in mechanically ventilated patients with severe acute asthma.

Acute physiology and chronic health evaluation (APACHE II) scoring in a cardiothoracic intensive care unit.

OBJECTIVE: To evaluate the predictive value of the Acute Physiology and Chronic Health Evaluation (APACHE II) scoring system in cardiothoracic surgical patients. DESIGN: Prospective survey with follow-up to hospital discharge. SETTING: A cardiothoracic surgical ICU in a tertiary referral center. PATIENTS: Eight hundred sixty-nine consecutive patients admitted to the ICU were entered into this study. Data on 12 patients were incomplete. Forty-three patients had nonsurgical diagnoses. Three patients had noncardiothoracic operations. These exclusions left 811 patients for analysis, and all results pertain to these 811 cardiothoracic surgical patients. INTERVENTIONS: Demographic and physiologic data relevant to the APACHE II score were collected on all patients and entered into a microcomputer database for analysis. MEASUREMENTS AND MAIN RESULTS: The following procedures were performed: 65% of patients had coronary artery bypass grafts; 23% had heart valve surgery; 5% had thoracic surgical procedures; and the remainder had a variety of cardiothoracic operations. The mean duration of ICU care was 2.3 days and the mean age was 57 yrs. The mean APACHE II score was 9.5 and the overall predicted risk of dying was 4.59%, with an actual ICU mortality rate of 4.56%. The relationship between the APACHE II score and mortality rate was linear and significant (p less than .001). Patients with an APACHE II score of less than 10 had a mortality rate of 0.93%. Only a score of greater than 30 was uniformly associated with death, and then only in one patient. A chronic disease history, emergency surgery, and a longer ICU stay were significant markers for mortality. CONCLUSIONS: There was a good relationship between the APACHE II score and mortality rate. Low APACHE II scores accurately predicted survival but only very high scores accurately predicted death.

The effects of dopexamine hydrochloride on cardiopulmonary haemodynamics following cardiopulmonary bypass surgery.

We studied the effects of dopexamine hydrochloride in 14 patients following cardiopulmonary bypass for coronary revascularisation (12 patients) or valve replacement (2 patients). The drug was administered by intravenous infusion at rates of 1, 2, 4 and 6 micrograms/kilogram/minute for a period of 10 minutes at each dose. Measurements of heart rate, blood pressure, right atrial pressure, pulmonary arterial pressure, pulmonary arterial wedge pressure and cardiac output (thermodilution method) were made at the end of each period. There were significant increases in heart rate (P less than 0.05), cardiac index (P less than 0.05) and systolic blood pressure (P less than 0.05). There were significant falls in systemic vascular resistance (P less than 0.05) and pulmonary vascular resistance (P less than 0.05). There were no significant changes in pulmonary arterial or wedge pressure. No serious adverse effects were observed. Dopexamine hydrochloride appears to be a useful supportive agent in patients following cardiopulmonary bypass, although further trials need to be carried out in order to establish precise therapeutic indications for its use.

Moxalactam kinetics during continuous ambulatory peritoneal dialysis after intraperitoneal administration.

Moxalactam kinetics during continuous ambulatory peritoneal dialysis (CAPD) was followed in eight patients after a single intraperitoneal dose of 1 g. Approximately 60% of the dose was absorbed after a dwell time of 4 h. Dialysis solutions were exchanged at 4-h intervals with an overnight dwell of 8 h. The mean (+/- standard deviation) elimination half-life was 13.2 +/- 2.9 h, and the mean apparent volume of distribution was 0.22 +/- 0.08 liters/kg. Mean total clearance was 11.5 +/- 2.4 ml/min, with a mean dialysis clearance of 2.3 +/- 0.5 ml/min. The maximum concentration in plasma ranged from 24.5 to 54.1 micrograms/ml. Moxalactam concentrations in the peritoneal dialysis fluid were above 80 micrograms/ml during the first exchange and above 2 micrograms/ml for a further three exchanges. A suggested intraperitoneal dose regimen for patients undergoing CAPD is 1 g initially, followed by 15 to 25% of the recommended dose for normal patients given at the same time intervals, or 30 to 50% of the recommended dose at twice the usual intervals. Moxalactam is suggested for initial treatment of peritonitis in CAPD patients who do not have ready access to the antibiotic of choice.