RESUMEN

BACKGROUND: Studies have shown right ventricular end-diastolic volume (RVEDV) to be a more accurate estimate of left ventricular preload than pulmonary artery wedge pressure. We prospectively evaluated the ability of RVEDV to predict left ventricular end-diastolic volume (LVEDV) in critically ill patients. METHODS: Thirty critically ill patients in the surgical intensive care unit underwent concurrent measurement of RVEDV and LVEDV. RVEDV was measured using a residual fraction Swan-Ganz catheter (RF Swan). LVEDV was measured using transesophageal echocardiography with acoustic quantification. Intracardiac, intra-abdominal, and ventilatory pressures were also measured. RESULTS: RVEDV as measured by the RF Swan was significantly larger (by a factor of 2) than LVEDV (p < 0.0001 analysis of variance). However, the RVEDV and LVEDV were strongly correlated (r = 0.71, p < 0.0001, Pearson's correlation). CONCLUSIONS: RVEDV from the RF Swan markedly overestimated left ventricular preload. If RVEDV is used as an absolute value for determining preload, patients may be underresuscitated. Transesophageal echocardiography in conjunction with RF Swan can be used to more accurately determine preload and cardiac performance than RF Swan alone in critically ill patients.

Asunto(s)

Asunto(s)

RESUMEN

The efficacy of intraoperatively administered ketorolac for the prophylactic treatment of pain in the postanesthesia care unit (PACU) was examined in a prospective, double-blinded study. Thirty patients undergoing general anesthesia for orthopedic or lower abdominal surgery were randomized into two groups. Both groups received equivalent doses of opioids intraoperatively. Upon surgical closure, one group received intramuscular (IM) ketorolac 60 mg (2 mL) and the other group received normal saline 2 mL, IM. The saline control group more frequently required opioid-analgesic supplementation in the PACU than did the ketorolac group (P < 0.05). Time to first-required opioid dose in the PACU was 22 +/- 8 versus 76 +/- 11 min for the control group and ketorolac group, respectively (P < 0.001). The ketorolac group reported significantly lower pain scores 1 hr after PACU admission (P < 0.01). Time to PACU discharge was not different between groups. Intraoperatively administered ketorolac is an effective adjunct in the management of postoperative pain.

Asunto(s)

Asunto(s)

RESUMEN

The effects of i.v. alfentanil on the intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were prospectively evaluated during endotracheal suctioning of head-injured adults. Seven subjects underwent trials of saline and alfentanil at 15 and 30 micrograms/kg prior to a stereotypic stimulus of endotracheal suctioning. Investigators and medical personnel were blinded with respect to the intravenous substance administered. The ICP, mean arterial pressure (MAP), heart rate (HR), peak and plateau inspiratory pressures, and Glasgow Coma Scores were recorded. By analysis of variance with repeated measures, data demonstrated that the alfentanil trials were associated with a decline in the CPP relative to control. The CPP was significantly reduced (p < 0.05) in the alfentanil dosage trials 5 min after i.v. alfentanil injection. There was no evidence of alteration of chest wall compliance to explain apparent elevations in the ICP or reductions in the MAP. These findings suggest caution in the use of alfentanil in the neurotrauma patient. Potential mechanisms of reduction in cerebral perfusion will require further evaluation. Formal assessment of other synthetic opiates with respect to efficacy and safety in the neurotrauma patient is advised.

Asunto(s)

RESUMEN

To investigate the basis of ambiguous reports of the validity and utility of processed electroencephalogram (EEG) detection of cerebral ischemia, 19 patients monitored during surgical procedures requiring clamping of the carotid artery were studied. The EEG was recorded and observed for detection of alteration of spectral edge frequency versus EEG power. Electrodes were positioned at the P3-C3' locations over the left hemisphere and P4-C4' areas over the right hemisphere (10-20 system of electrode placement). Maximum sensitivity was used for recordings of the processed EEG. Twelve of 19 patients had bilateral carotid vascular stenosis. Nine of 19 patients studied with EEG monitoring had EEG changes suggestive of cerebral ischemia during interruption of carotid artery blood flow by surgical manipulation, defined as a decline in EEG power of greater than 40% or a decline in spectral edge frequency of at least 3 Hz. Eight of these episodes occurred at the time of carotid vascular clamp placement. These changes were confirmed by the raw EEG. Whereas power band monitoring detected 9 episodes of suspected ischemia, alteration of spectral edge frequency was sufficient to detect only 2 of these episodes. One patient sustained a right hemispheric stroke detected intraoperatively by a 47% decline in EEG power; however, these changes were unaccompanied by intraoperative alteration of spectral edge frequency. It is concluded that monitoring of EEG power with processed EEG devices is a more sensitive indicator of cerebral ischemia than monitoring only the spectral edge frequency of the EEG.

Asunto(s)

Asunto(s)

RESUMEN

We studied the incidence and mechanisms of cardiovascular complications and postoperative respiratory insufficiency associated with GA and Nd:YAG laser endobronchial tumor resection. The records of 73 patients undergoing 87 procedures were reviewed. Preoperative status, anesthetic methods and perioperative complications were analyzed by multiple regression to determine predictors of outcome. Twenty-three percent of patients had greater than 90 percent mainstem bronchus obstruction. Longer serum elimination half-life of relaxant drug was significantly correlated with longer duration of mechanical ventilation after neuromuscular blockade reversal. Cardiovascular complications were noted in 24 procedures and often required therapeutic intervention. Variables predicting cardiovascular complications included longer duration of GA and increasing age. Perioperative respiratory and cardiovascular complications are common after GA for Nd: YAG laser resection. Short-acting neuromuscular relaxants, careful assessment prior to postoperative extubation, limiting duration of GA and cardiovascular monitoring are recommended when implementing GA for Nd: YAG laser resection of endobronchial tumors.

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

RESUMEN

The perioperative management of the geriatric patient with critical illness is a challenge for even the most skilled anesthesiologist. Careful preoperative assessment and preparation are essential. Optimal therapy requires application of appropriate monitoring, accurate interpretation of hemodynamic data, and appropriate selection and administration of anesthetics and therapeutic interventions. The hemodynamic compromise of critical illness is compounded by underlying pathophysiology in the aged. These factors lend a complexity to the treatment of the geriatric patient with hemodynamic instability that necessitates the anesthesiologist's implementation of the most current technological and pharmacological modalities in the operating room and intensive care unit.

Asunto(s)

Asunto(s)