Assessment of changes in intra-abdominal pressure and abdominal perfusion pressure in late-term pregnant queens undergoing elective ovariohysterectomy.

OBJECTIVE: Compare changes in intra-abdominal pressure (IAP), abdominal perfusion pressure (APP), hemodynamics, and clinicopathological variables in nonpregnant and late-term pregnant queens undergoing elective ovariohysterectomy (OHE) and evaluate the effect of patient positioning on IAP and APP measurements. ANIMALS: 18 late-term pregnant queens and 25 nonpregnant controls. PROCEDURES: Temperature, heart rate (HR), Doppler blood pressure (DBP), IAP (dorsal and right lateral), PCV, total protein (TP), and lactate were recorded preoperatively, at abdominal wall closure (dorsal IAP only), and postoperatively under general anesthesia. Uterine weight, blood loss, and surgical duration were recorded. Abdominal perfusion pressure was calculated as DBP minus IAP. RESULTS: Pre- and postoperatively, pregnant queens had lower DBP, APP, and PCV compared to controls (P < 0.001). IAP was higher in pregnant queens preoperatively (P < 0.001). Controls had a decrease in HR and increase in IAP, while both groups had a decrease in body temperature, DBP, APP, and lactate over time (P < 0.05). Pregnant queens had a decrease (P = 0.029), and controls had an increase in TP (P = 0.001). Blood loss and surgical time were greater for pregnant queens (P < 0.001). Dorsal IAP and APP were higher and lower than right lateral measurements (P < 0.001), respectively, and correlation was strong. CLINICAL RELEVANCE: Hemodynamics and APP are impaired in late-term pregnant queens undergoing OHE, and increased monitoring is warranted. Although strongly correlated, feline IAP and APP measurements in dorsal and right lateral recumbency are not interchangeable.

Influence of the mode of ventilation on ketamine/xylazine requirements in rabbits.

OBJECTIVE: To evaluate the effect of the mode of mechanical ventilation (MV) on the dose of intravenous anesthetic during 3 hours of ketamine/xylazine anesthesia. STUDY DESIGN: Prospective laboratory study. ANIMALS: Sixty-one adult male New Zealand White rabbits. METHODS: Rabbits were anesthetized (ketamine/xylazine 35 + 5 mg kg(-1), IM), the trachea was intubated and randomized to four groups - (1) CMV-1 (n = 14), ventilated with traditional conventional volume-cycled MV [V(T) = 12 mL kg(-1), RR = 20, positive end-expiratory pressure (PEEP) = 0 cmH(2)O]; (2) CMV-2 (n = 13), ventilated with a modern lung-protective regimen of volume-cycled MV (V(T) = 6 mL kg(-1), RR = 40, PEEP = 5 cmH(2)O); (3) HFPV (n = 17) ventilated with high-frequency percussive ventilation [high-frequency oscillations (450 minute(-1)) superimposed on 40 minute(-1) low-frequency respiratory cycles, I:E ratio = 1:1], oscillatory continuous positive airway pressure (CPAP) of 7-10 cmH(2)O, and demand CPAP of 8-10 cmH(2)O. (4) A fourth group, spontaneously ventilating (SV, n = 17), was anesthetized, intubated, but not ventilated mechanically. FiO(2) in all groups was 0.5. Anesthesia was maintained at a surgical plane by IV administration of a ketamine/xylazine mixture (10 + 2 mg kg(-1), as necessary) for 3 hours after intubation. Total dose of xylazine/ketamine administered and the need for yohimbine to facilitate recovery were quantitated. RESULTS: The total dose of xylazine/ketamine was significantly higher in the HFPV and SV groups compared with CMV-1 (p < 0.01). Fewer animals required yohimbine to reverse anesthesia in the HFPV than CMV-1 group (p < 0.05). CONCLUSIONS: The HFPV mode of MV led to higher doses of ketamine/xylazine being used than the other modes of MV. CLINICAL RELEVANCE: In rabbits, anesthetic dose for the maintenance of anesthesia varied with the mode of MV used. Investigators should be aware of the possibility that changing the mode of ventilation may lead to an alteration in the amount of drug required to maintain anesthesia.

Addition of a propyl gallate-based procoagulant to a fibrin bandage improves hemostatic performance in a swine arterial bleeding model.

Fibrin bandages manufactured by Nycomed Austria (TC-S) were modified by the addition of Hemostyptin (HS), a proprietary platelet-activating reagent containing propyl gallate. HS was added as an additional layer to TC-S fibrin bandages and the bandages were tested for hemostatic efficacy in a swine femoral artery bleeding model. Injuries were treated with a TC-S+HS bandage preparation using HS lyophilized onto a bandage surface that was then attached to the fibrin dressing. This preparation qualitatively and quantitatively exhibited more robust blood clotting at the surgical site than the control bandages. TC-S+HS bandages were more effective than control bandages with a difference in blood loss of 251.8+/-66.5 g for TC-S bandage alone, n=12 vs. 121+/-40.7 g, n=13 for the TC-S+HS bandage, P=0.05. Bleeding times were shortened for animals treated with the HS fortified bandages and residual platelets counts in these animals were higher.

Epsilon-amino caproic acid additive decreases fibrin bandage performance in a swine arterial bleeding model.

epsilon -Amino caproic acid (EACA), a lysine analog that inhibits the activity of plasmin, was added to Nycomed (TC-S) fibrin bandages, and the bandages were tested for hemostatic efficacy in a swine femoral artery bleeding model. The blood loss using the bandage with EACA (TC-S+EACA; 728.8+/-132 g, n=5) was much greater as compared to the TC-S bandage alone (TC-S; 237.8+/-47.9 g, n=6, p=.02). The time to "cessation of bleeding" (T(b)) was also increased for animals treated with TC-S+EACA bandages compared to the TC-S controls (33.6+/-10.8 min vs. 9.2+/-2.2 min; p=.05). Although plasma fibrinogen concentration decreased in animals treated with the TC-S+EACA bandage, activated partial thromboplastin times (aPTT) and thrombin times (TT) were decreased. Animals treated with the TC-S control bandage exhibited no changes in fibrinogen, aPTT or TT. Prothrombin times (PT) were unchanged in either group. In conclusion, addition of EACA to the Nycomed product decreased fibrin bandage efficiency.