Brian S. Kaufman

Fluid resuscitation in circulatory shock: a comparison of the cardiorespiratory effects of albumin, hetastarch, and saline solutions in patients with hypovolemic and septic shock.

Twenty-six consecutive patients in hypovolemic shock were randomized to fluid challenge with 5% albumin (A), 6% hetastarch (H), or 0.9% saline (S) solutions. Fluid challenge consisted of 250 ml of test fluid every 15 min until the pulmonary artery wedge pressure (WP) reached 15 mm Hg. Thereafter, WP was maintained at 15 mm Hg for an additional 24 h with infusions of the same test fluid. Vital signs, hemodynamic and respiratory variables, as well as arterial lactate and colloid osmotic pressure (COP) were monitored according to protocol. Chest x-rays were performed by standardized technique before fluid challenge and at 12 and 24 h of maintenance fluid therapy and were evaluated for evidence of pulmonary edema. Cardiac function and hemodynamic stability were restored by fluid challenge with A, H, and S. Two to 4 times the volume of S as A or H was required to achieve similar hemodynamic endpoints. COP was increased by fluid challenge with A or H but was markedly reduced by fluid challenge with S and throughout the 24-h maintenance period. Fluid challenge resulted in reductions in COP-WP gradient of 62% in the A, 43% in the H, and 125% in the S groups. Resuscitation with S resulted in a significantly higher incidence of pulmonary edema (87.5%) than did resuscitation with A (22%) or H (22%). Urine output was not different among the groups at any time during the study. We conclude that 6% H performs as well as 5% A as a resuscitative fluid and that resuscitation with either of these colloids is associated with a lower incidence of pulmonary edema than is resuscitation with 0.9% S.

Oxygen delivery and consumption in patients with hyperdynamic septic shock.

We analyzed the relationship of increases in oxygen delivery to changes in oxygen consumption in ten patients with hyperdynamic septic shock. Increases in oxygen delivery from 413 ± 14 (SEM) to 535 ± 19 ml/min-m2 (p < .01) were associated with increases in oxygen consumption from 136 ± 10 to 161 ± 5 ml/min-m2 (p < .05). Arterial lactate decreased from 4.6 ± 1.6 to 2.1 ± 0.3 mmol/L (p < .05). These observations suggest that oxygen utilization is perfusion-limited in hyperdynamic septic shock.

Relationship of oxygen delivery and mixed venous oxygenation to lactic acidosis in patients with sepsis and acute myocardial infarction

Critical decreases in oxygen delivery (DO2) and mixed venous oxygen saturation (SvO2) are associated with anaerobic metabolism and, therefore, lactic acidosis. We studied 50 consecutive patients with sepsis and 50 consecutive patients with acute myocardial infarction (AMI) in whom the arterial blood lactate was greater than 1 mmol/L in order to determine critical thresholds of DO2 and SvO2. In both groups, critical values of DO2 or SvO2 associated with lactic acidosis could not be identified. The DO2 ranged from 136 to 811 ml/min.m2 and SvO2 ranged from 28% to 73% in the patients with sepsis. The DO2 ranged from 115 to 434 ml/min.m2 and SvO2 from 17% to 72% in patients with AMI. The absence of threshold values for DO2 and SvO2 probably reflects the influence of distributive flow abnormalities as well as differences in metabolic requirements in these critically ill patients.

Early diagnosis of spinal—epidural metastasis by magnetic resonance imaging

Sixteen patients with various types of cancer who developed pain along the axial spine were prospectively studied by magnetic resonance imaging (MRI). The studies were performed with a Fonar Beta‐3000 (Fonar Co., Melville, NY) permanent magnet operating at 0.3 Tesla (T). Detailed neurologic examinations were followed by bone x‐rays, bone scans, and MRI. In 12 patients there were focal neurologic findings. Bone x‐rays and bone scans were diagnostic for metastatic disease in 10 cases; MRIs were consistent with metastatic spinal—epidural disease in all 16 patients. Magnetic resonance imaging revealed bone involvement in three patients whose x‐rays and bone scans were both negative indicating a higher degree of sensitivity. In six patients thecal compression was obvious on MRI; in three of these previous myelograms had been interpreted as negative. These early results suggest that MRI can serve as a useful tool for diagnosing early spinal—epidural metastases. Cancer 59:1112‐1116, 1987.

RESOLUTION OF LACTIC ACIDOSIS AFTER SEDATION OF A PATIENT WITH ACUTE MYOCARDIAL INFARCTION AND LEFT VENTRICULAR FAILURE

The hemodynamic and metabolic effects of sedation in patients with acute myocardial infarction complicated by severe left ventricular failure have not been well studied. We report a patient with this diagnosis, in whom sedation resulted in resolution of lactic acidosis

Did Video Kill the Direct Laryngoscopy Star? Not Yet!

We read with interest “Difficult Airway Characteristics Associated with First Attempt Failure at Intubation Using Video Laryngoscopy in the Intensive Care Unit” (1). In that article, Joshi and colleagues assessed determinants of unsuccessful efforts by physicians in training to perform orotracheal intubation, using predominantly combined video and direct laryngoscopy devices (C-MAC; Karl Storz, Tuttlingen, Germany). After each intubation, the operators completed a data collection form, allowing the authors to analyze factors associated with failure of first-pass placement of an endotracheal tube. They identified several factors that contributed to first-pass failure; notably, blood in the airway, cervical immobility, airway edema, and obesity. The study by Joshi and coauthors adds to the existing literature in several ways, including the use of a nonanesthesia house staff intubating cohort, data on video-assisted intubations, trainee performance using combined video and direct laryngoscopy equipment, and the pinpointing of possible impediments to successful intubation. However, there are several items that require further clarification. First, the standard approach employed in this study when trainees used a device with both direct and indirect capabilities, such as the Storz C-MAC or GlideScope Direct Intubation Trainer (Verathon, Bothell, WA), is of clinical consequence. If glottis visualization was obscured, did the residents and fellows perform primarily direct laryngoscopy with a video “rescue,” or did they use primarily an indirect approach with a direct laryngoscopy rescue? The reason why blood in the airway caused failure is also of interest. Were these failures primarily a result of inability to visualize the larynx with the video device, or primarily a failure of an effort that combined direct and indirect laryngoscopy? In addition, it would be helpful to disclose details regarding bougie/introducer devices or laryngeal manipulation techniques in patients for whom a view was not possible using a video approach (assuming a nonhyperangulated blade was used). Second, the influence of the supervising physician is relevant, regarding the success of the procedures. Two recent investigations comparing success rates of direct-to-video laryngoscopy attempted by pulmonary and critical care fellows included immediate attending feedback and coaching (verbal communication) (2, 3). Information on the supervisory role of attending physicians is not included in the current report. Third, in their investigation of factors associated with failure to achieve first-pass successful intubation, Joshi and associates found that limited mouth opening was highly prevalent in both groups (24/166 of first-attempt failures, 64/740 in first-attempt success). However, an operational definition of limited mouth opening is not clearly stated in the report. In a multivariate risk index study of preoperative endotracheal intubation attempts by experienced anesthesiologists, mouth opening, defined as an interincisor tooth gap of ,4 cm, was found to have a positive predictive value for difficult intubation of 25% (4). In another study of difficult routine preoperative intubations, measured mouth opening (interincisor distance) was also strongly associated with easy vs. difficult intubation (5). Therefore, it would be of interest to know how limited mouth opening was defined and measured in the Joshi study. Finally, knowing the urgency of the endotracheal attempts is necessary to place the results of this investigation in an appropriate clinical context (1).