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Data directly comparing CO2 absorbents tested in identical and clinically relevant conditions are scarce or non-existent. We therefore tested and compared the efficiency of 16 different brands of Ca(OH)2 based CO2 absorbents used as loose fill or a cartridge in a refillable canister under identical low flow conditions. CO2 absorbents efficiency was tested by flowing 160 mL/min CO2 into the tip of a 2 L balloon that was ventilated with an ADU anesthesia machine (GE, Madison, WI, USA) with a tidal volume of 500 mL and a respiratory rate of 10/min while running an O2/air FGF of 300 mL/min. After the 1020 mL refillable container was filled with a known volume of CO2 absorbent (derived from weighing the initial canister content and the product's density), the time for the inspired CO2 concentration (FICO2) to rise to 0.5% was measured. This test was repeated 4 times for each product. Because the two SpiraLith Ca® products (one with and one without indicator) are delivered as a cartridge, they had to be tested using their proprietary canister. The time (min) for FICO2 to reach 0.5% was normalized to 100 mL of product, and defined as the efficiency, which was compared amongst the different brands using ANOVA. Efficiency ranged from 50 to 100 min per 100 mL of product, and increased with increasing NaOH content (a catalyst), the exception being SpiraLith Ca® cartridge with color indicator (performing as well as the most efficient granular products) and the SpiraLith Ca® cartridge without color indicator (outperforming all others). Results indicated a spherical or bullet shape is less efficient in absorbing CO2 than broken fragments or cylinders, which in turn is less efficient than a hemispherical (disc) shape, which is in turn less efficient than a solid cartridge with a molded channel geometry. The efficiency of Ca(OH)2 based CO2 absorbent differs up to 100% on a volume basis. Macroscopic arrangement (cylindrical wrap with preformed channels versus granules), chemical composition (NaOH content), and granular shape all affect efficiency per volume of product. The data can be used to compare costs of the different products.

The aim of this prospective, randomized and double-blind study was to assess the effects of a high dose of the analgesic tramadol administered at the conclusion of surgery on extubation time, sedation, and post-anaesthetic shivering. Forty adult patients, ASA physical status I or II, underwent laparoscopic surgery of about 1 h duration and received a standardized anaesthesia that was maintained with isoflurane in O2/N2O. Tramadol 3 mg kg-1 (n = 20) was administered intravenously at the beginning of wound closure, and was compared with saline (n = 20). Post-anaesthetic shivering did not occur in any patient who received tramadol, whereas it occurred in 60% of the control group (P < 0.001). There were no adverse effects on time to extubation and sedation, and discharge-ready time was shorter in the tramadol group (P < 0.05 compared with control). Pain scores in the post-anaesthesia care unit (PACU) were statistically not different between the two groups, but significantly more supplemental medication was administered in the control group to treat shivering and/or pain. In conclusion, administration of a high dose of tramadol at the end of surgery prevents post-anaesthetic shivering without prolongation of extubation time, and shortens the PACU/discharge-ready time.

Ketanserin, a selective S2-serotonin receptor blocker with alpha 1-adrenergic blocking effects, may be a suitable antihypertensive medication after coronary artery surgery and lacks side effects seen with other vasodilators. Fifty patients with systolic blood pressures greater than 150 mmHg after coronary artery surgery were given, in a randomized double-blind fashion, either ketanserin (K) or saline (S). Each patient received six successive boluses of 1 mL of S or 1 mL of K (5 mg) at 2-minute intervals. After the last injection, sodium nitroprusside was started whenever the systolic blood pressure exceeded 150 mmHg. In the K group, the following significant (P < 0.05) changes occurred: systolic and diastolic arterial pressure -12% and -11%, respectively; heart rate -3%; systolic and diastolic pulmonary artery pressure -5% and -6%; central venous pressure -5%; pulmonary capillary wedge pressure -5%; systemic vascular resistance -16%; pulmonary vascular resistance -8%; stroke index +6%. None of these parameters changed significantly in the S group. There was no change in pulmonary shunt fraction in either group. In the K group, five patients did not require any further antihypertensive therapy during the 120 minutes following the last bolus injection. Twenty patients needed sodium nitroprusside during this period. This occurred 37 minutes (+/- 17 min) after the last bolus. In conclusion, after coronary artery bypass surgery, K is an effective antihypertensive medication, which does not cause reflex tachycardia or an increase in pulmonary shunt fraction. Exceeding the recommended dose of 10 (or 20) mg, as done in this study, does not seem to improve effectiveness or prolong the duration of action.

Tight blood glucose control reduces mortality and morbidity in critically ill patients, but intraoperative glucose control during cardiac surgery is often difficult, and risks hypoglycemia. In this study, we evaluated the safety and efficacy of a nurse-driven insulin protocol (the Aalst Glycemia Insulin Protocol) for achieving a target glucose level of 80-110 mg/dL during cardiac surgery and in the intensive care unit (ICU).We included 483 nondiabetics and 168 diabetics scheduled for cardiac surgery with cardiopulmonary bypass. To anticipate rapid perioperative changes in insulin requirement and/or sensitivity during surgery, we developed a dynamic algorithm presented in tabular form, with rows representing blood glucose ranges and columns representing insulin dosages based on the patients' insulin sensitivity. The algorithm adjusts insulin dosage based on blood glucose level and the projected insulin sensitivity (e.g., reduced sensitivity during cardiopulmonary bypass and normalizing sensitivity after surgery).A total of 18,893 blood glucose measurements were made during and after surgery. During surgery, the mean glucose level in nondiabetic patients was within targeted levels except during (112 +/- 17 mg/dL) and after rewarming (113 +/- 19 mg/dL) on cardiopulmonary bypass. In diabetics, blood glucose was decreased from 121 +/- 40 mg/dL at anesthesia induction to 112 +/- 26 mg/dL at the end of surgery (P0.05), with 52.9% of patients achieving the target. In the ICU, the mean glucose level was within targeted range at all time points, except for diabetics upon ICU arrival (113 +/- 24 mg/dL). Of all blood glucose measurements (operating room and ICU), 68.0% were within the target, with 0.12% of measurements in nondiabetics and 0.18% in diabetics below 60 mg/dL. Hypoglycemia50 mg/dL was avoided in all but four (0.6%) patients (40 mg/dL was the lowest observed value).The Aalst Glycemia Insulin Protocol is effective for maintaining tight perioperative blood glucose control during cardiac surgery with minimal risk of hypoglycemia.

Postoperative residual paralysis is an important complication of the use of neuromuscular blocking drugs. In this prospective study, the incidence of residual paralysis detected as a train-of-four response

Nine NYHA class III-IV patients awaiting heart transplantation (HTx) were studied with a right ventricular ejection fraction (RVEF) catheter. The first aim of the study was to explore the pulmonary and systemic circulatory effects of dobutamine (D) and/or nitroprusside (N) in these patients. The second aim was to search for the parameter(s) among those usually measured that best predicted RVEF. Baseline data were recorded after 30 minutes of stabilization. Then, three drug regimens were administered in a randomized order for 30 minutes each: D, 4 micrograms/kg/min; N, 0.25 to 1.0 micrograms/kg/min; and their combination. Significant changes in RV loading and function were observed with all three therapies. The combination of both drugs was superior to either drug alone. The best predictor of RVEF was pulmonary arterial elastance. The second best was pulmonary capillary wedge pressure (PCWP). Pulmonary artery pressures, pulmonary vascular resistances, and transpulmonary gradient (TPG) were of less predictive value, as shown by a multiple regression analysis. None of the drugs showed any selectivity for the pulmonary vasculature, because the ratio PVRI/SVRI was never changed significantly. Selective pulmonary arterial vascular smooth muscle relaxation is probably not the most important mechanism to explain the unloading and improvement in function of the RV with D and/or N. Improved myocardial pump function appears to be the major factor in unloading the RV via reduction of PCWP and mean pulmonary artery pressure with essentially no change in TPG. The RVEF catheter provides valuable additional information in the screening of HTx candidates for pulmonary hypertension.