Abdominal Hypertension and Liver Dysfunction in Intensive Care Unit Patients: An “On-Off” Phenomenon?

Intra-abdominal hypertension (IAH) can affect liver hemodynamics but it is not known if has a significant clinical impact on liver function. The aim of this study was to investigate the relationship between IAH and liver function. A prospective study was performed in 110 adult intensive care unit (ICU) patients. Intra-abdominal pressure (IAP) was measured on admission and every other day, and liver sequential organ failure assessment (SOFA) score was collected whenever IAP was measured. IAH was defined by a IAP >or= 10 mm Hg, and liver dysfunction was defined by a hepatic SOFA score >or= 2. An overall IAH incidence of 56.3% was found (n = 62). Thirty-three patients presented a liver SOFA score >or= 2, with an overall incidence of 30%. Liver SOFA score of the group of patients with abdominal hypertension was higher than in group of patients without abdominal hypertension. (0.8 +/- 1.05 vs 0.4 +/- 0.7; P < .05), but IAH and liver dysfunction were not significantly associated (chi2 = 2.03; P = .15). When the whole sample was divided according to the worst IAP score (IAP < 10, IAP between 10 and 15, and IAP > 15), the corresponding liver dysfunction scores in the three groups were 0.35 +/- 0.6, 0.74 +/- 1, and 1.2 +/- 1.3, respectively (P = .01). A strict association between IAH and liver dysfunction was not found. Most likely, low levels of IAH, although able to reduce liver blood flow, are not per se sufficient to produce a real dysfunction; however, a correlation between the degree of IAH and the degree of hyperbilirubinemia exists. IAH does not seem to be an "on-off" phenomenon, but produces liver alterations for increasing levels of its severity.     

Transesophageal echocardiography for diagnosis of traumatic aortic injury: an appraisal of the evidence

BACKGROUNDS: An overview of the validity of transesophageal echocardiography (TEE) in patients suspected to have traumatic aortic injury (TAI). METHODS: Computerized bibliographic search of trials from 1994 to 2002 evaluating the use of TEE to confirm the diagnosis of TAI. Seven relevant studies out of 204 were identified, involving 758 patients. The accuracy of TEE was analyzed by constructing summary receiver-operating characteristic (sROC) curves and computing areas under the sROC curve. RESULTS: No prospective randomized trial was found. Although accuracy varied greatly, summary ROC curve found that TEE enjoyed a high diagnostic performance. Some study characteristics can affect accuracy. CONCLUSIONS: Our findings seems to indicate that TEE is a valuable tool for diagnosing TAI, and its use as first-line evaluation of such patients can be supported; however, given the lack of randomized trials, no standard of care can be drawn from the present overview: future studies should look at this problem more carefully, and should be methodologically rigorous.     

Effects of positive end-expiratory pressure on right ventricular function in COPD patients during acute ventilatory failure

Objective To examine the effects of external positive end-expiratory pressure (PEEP) on right ventricular function in chronic obstructive pulmonary disease (COPD) patients with intrinsic PEEP (PEEPi).Design Prospective study.Setting General intensive care unit in a university teaching hospital.Patients Seven mechanically ventilated flow-limited COPD patients (PEEPi=9.7±1.3 cmH₂O, mean±SD) with acute respiratory failure.Intervention Hemodynamic and respiratory mechanic data were collected at four different levels of PEEP (0-5-10-15 cmH₂O).Measurements and results Hemodynamic parameters were obtained by a Swan-Ganz catheter with a fast response thermistor. Cardiac index (CI) and end-expiratory lung volume (EELV) reductions started simultaneously when the applied PEEP was approximately 90% of PEEPi measured on 0 cmH₂O (ZEEP). Changes in transmural intrathoracic pressure (PEEPi,cw) started only at a PEEP value much higher (120%) than PEEPi. The reduction in CI was related to a decrease in the right enddiastolic ventricular volume index (RVEDVI) (r=0.61;p<0.001). No correlation between CI and transmural right atrial pressure was observed. The RVEDVI was inversely correlated with PEEP-induced changes in EELV (r=–55;p<0.001), but no with PEEPi,cw (r=–0.08; NS). The relationship between RVEDVI and right ventricular stroke work index, considered an index of contractility, was significant in three patients, i.e., PEEP did not change contractility. In the other patients, an increase in contractility seemed to occur.Conclusions In COPD patients an external PEEP exceeding 90% of PEEPi causes lung hyperinflation and reduces the CI due to a preload effect. The reduction in RVEDVI seems related to changes in EELV, rather than to changes in transmural pressures, suggesting a lung/heart volume interaction in the cardiac fossa. Thus, in COPD patients, application of an external PEEP level lower than PEEPi may affect right ventricular function.This study was supported in part by a grant from the Consiglio Nazionale delle Ricerche, Italy     

Independent lung ventilation in patients with unilateral pulmonary contusion. Monitoring with compliance and EtCO2

OBJECTIVE: a) to describe a non-barotraumatic ventilatory setting for independent lung ventilation (ILV); b) to determine the utility of single lung end-tidal CO(2) (EtCO(2)) monitoring to evaluate the ventilation to perfusion (V/Q) matching in each lung during ILV and for ILV weaning. DESIGN: prospective study. SETTING: general intensive care unit in a university teaching hospital. PATIENTS: twelve patients with unilateral thoracic trauma needing ILV. INTERVENTIONS AND RESULTS: ILV was started with each lung ventilated with the same tidal volume (Vt): plateau airway pressure (Pplat) was 34.2+/-3.2 cmH2O in diseased lungs (DL) and 18.1+/-1.9 cmH2O in normal lungs (NL) ( P<0.01). Static compliance (Cst) was 9.9+/-1.1 ml/cmH(2)O in DL and 19.3+/-1.7 ml/cmH(2)O in NL ( P<0.01). EtCO2 was 22.5+/-2.2 mmHg in DL and 36.6+/-1.9 mmHg in NL ( P<0.01). PaO(2)/FiO(2) was at 151+/-20. PEEP was applied on the DL and each lung was ventilated with a Vt that developed Pplat < or =26 cmH2O. With this setting, Vt given to the NL was unchanged, whereas it was reduced in the DL (238+/-30 ml vs 350+/-31 ml; P<0.01). Cst and EtCO2 were still significantly lower in the DL ( P<0.01, respectively), while the PaO(2)/FiO(2) ratio remained unchanged. Vt was then progressively increased in the DL as Pplat decreased, but remained unchanged in the NL. ILV was discontinued when Vt, Cst and EtCO(2) were the same in each lung. PaO(2)/FiO(2) ratio had then increased to 295+/-18. CONCLUSIONS: a) during ILV, adequate oxygenation and a reduction in V/Q mismatch can be obtained by setting Vt and PEEP to keep Pplat below a safe threshold for barotrauma; b) measurement of single lung EtCO2 can be useful to evaluate progressive V/Q matching.     

Patient-requested neuraxial analgesia for labor: impact on rates of cesarean and instrumental vaginal delivery

A systematic review, including a meta-analysis, on the timing effects of neuraxial analgesia (NA) on cesarean and instrumental vaginal deliveries in nulliparous women was conducted. Of 20 articles identified, 9 met the inclusion quality criteria (3,320 participants). Cesarean delivery (odds ratio, 1.00; 95% confidence interval, 0.82-1.23) and instrumental vaginal delivery (odds ratio, 1.00; 95% confidence interval, 0.83-1.21) rates were similar in the early NA and control groups. Neonates of women with early NA had a higher umbilical artery pH and received less naloxone. In the early NA group, fewer women were not compliant with assigned treatment and crossed over to the control group. Women receiving early NA for pain relief are not at increased risk of operative delivery, whereas those receiving early parenteral opioid and late epidural analgesia present a higher risk of instrumental vaginal delivery for nonreassuring fetal status, worse indices of neonatal wellness, and a lower quality of maternal analgesia.