Heart rate reduction with esmolol is associated with improved arterial elastance in patients with septic shock: a prospective observational study.

PURPOSE: Ventricular-arterial (V-A) decoupling decreases myocardial efficiency and is exacerbated by tachycardia that increases static arterial elastance (Ea). We thus investigated the effects of heart rate (HR) reduction on Ea in septic shock patients using the beta-blocker esmolol. We hypothesized that esmolol improves Ea by positively affecting the tone of arterial vessels and their responsiveness to HR-related changes in stroke volume (SV). METHODS: After at least 24 h of hemodynamic optimization, 45 septic shock patients, with an HR ≥95 bpm and requiring norepinephrine to maintain mean arterial pressure (MAP) ≥65 mmHg, received a titrated esmolol infusion to maintain HR between 80 and 94 bpm. Ea was calculated as MAP/SV. All measurements, including data from right heart catheterization, echocardiography, arterial waveform analysis, and norepinephrine requirements, were obtained at baseline and at 4 h after commencing esmolol. RESULTS: Esmolol reduced HR in all patients and this was associated with a decrease in Ea (2.19 ± 0.77 vs. 1.72 ± 0.52 mmHg l(-1)), arterial dP/dt max (1.08 ± 0.32 vs. 0.89 ± 0.29 mmHg ms(-1)), and a parallel increase in SV (48 ± 14 vs. 59 ± 18 ml), all p < 0.05. Cardiac output and ejection fraction remained unchanged, whereas norepinephrine requirements were reduced (0.7 ± 0.7 to 0.58 ± 0.5 µg kg(-1) min(-1), p < 0.05). CONCLUSIONS: HR reduction with esmolol effectively improved Ea while allowing adequate systemic perfusion in patients with severe septic shock who remained tachycardic despite standard volume resuscitation. As Ea is a major determinant of V-A coupling, its reduction may contribute to improving cardiovascular efficiency in septic shock.

Model-based evaluation of the Canberra Hospital Acute Care Surgical Unit : acute care surgery: a case of one size fits all?

PURPOSE: Surgical services in Australia are under sustained and growing pressure. The global implementation of acute care surgery services has been shown to facilitate the timeliness of acute surgery. The question is: Do acute care surgical units fit major regional centers like ours? The current study coincides with the introduction of a Surgical Assessment and Planning Unit (SAPU) at the Canberra Hospital and compares patient outcomes before vs. after the introduction of the SAPU, using acute appendicitis as the model illness. METHODS: We reviewed patients presenting to the Canberra Hospital Emergency Department with a preliminary diagnosis of acute appendicitis before vs. after the introduction of an acute care surgical unit. RESULTS: The subjects were 150 patients, ranging in age from 16 to 97 years. The mean time from presentation at casualty to surgical review and the surgical review itself was reduced by 19 and 26 %, respectively (p < 0.05). Time to the operating table and the percentage of after-hours operations were reduced by 8 and 40 %, respectively. There was a significant reduction in the utilization of abdominal ultrasonography after the implementation of the SAPU. CONCLUSIONS: The implementation of a SAPU has benefited the management of patients with acute surgical conditions. Ultimately, patient care is enhanced, with patients being reviewed, admitted, and treated earlier.

Seroprevalence of HIV in orthopaedic patients in Zimbabwe.

The prevalence of HIV infection in East Africa has increased rapidly in recent years. We made a prospective study of the incidence of HIV-seropositivity in patients undergoing orthopaedic procedures in a large district hospital in Bulawayo, Zimbabwe. One of our aims was to determine whether a clinically-based screening programme, derived from the Centre for Disease Control classification of HIV infection, could identify high-risk individuals before surgery. During a 3-month period, 76 patients were tested, and 12 were HIV-positive (16%). Only two of these patients (17%) had clinical features associated with HIV infection; ten (83%) were entirely asymptomatic. Our results indicate that preoperative clinical screening is unlikely to be successful in identifying seropositive patients before routine surgery.