[Treatment of cardiac failure with an intra-aortic balloon pump]. / Behandling av hjertesvikt med intraaortal ballongpumpe.

BACKGROUND: Cardiogenic shock is associated with high mortality. This retrospective study examined the effect of an intra aortic balloon pump (IABP) in patients with decompensated heart failure and hypotension, with or without cardiogenic shock. MATERIAL AND METHODS: 94 patients were treated with IABP from January 1998 to December 2002, at the Department of Cardiology, Rikshospitalet University Hospital, Oslo, Norway. The indications for use of IABP were decompensated heart failure with hypotension with or without cardiogenic shock in patients with acute myocardial infarction (n = 41), ventricular septal rupture or mitral insufficiency as a complication to acute cardiac failure (n = 23), severe heart failure waiting for heart transplant (n = 10), unstable angina pectoris (n = 8), myocarditis (n = 6) and miscellaneous (n = 6). RESULTS: Mortality after 30 days was 24 % for all patients, with little variation between the above-mentioned subgroups. Median duration for IABP was 96 hours. Systolic blood pressure and diuresis per hour increased significantly from before to after application of IABP (35 +/- 34 mL/hour versus 95 +/- 77 mL/hour, p < 0.001 and 90 +/- 20 mmHg versus 115 +/- 22 mmHg, p < 0.001). The rate of complications requiring treatment was low with use of IABP (5 out of 94 patients). INTERPRETATION: Treatment with IABP in patients with decompensated heart failure and hypotension is an efficient stabilising treatment and safe to use.

Cerebral outcome in adult patients treated with extracorporeal membrane oxygenation.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) carries a high risk of brain injury. The aim of this study was to determine the cerebral status in 28 adult survivors on average 5.0 (range, 0.5 to 12) years after ECMO treatment for severe cardiorespiratory failure. METHODS: All 28 patients were investigated at our institution. A comprehensive assessment protocol included a medical history, physical examination, neuropsychological assessment, electroencephalography, and neuroradiologic assessment. RESULTS: All patients were ambulant unaided, and 43% were without any clinical findings. Impaired neuropsychological performance was found in 41%, neuroradiologic findings in 52%, and a pathologic electroencephalogram in 41% of the patients. There was a significant correlation between the cognitive outcome and neuroradiologic findings. The incidence of neuroradiologic findings (cerebral infarction, microemboli or hemorrhage) was significantly higher in the venoarterial group compared with the venovenous group (75% versus 17%). There was no correlation between the type of ECMO and neuropsychological impairment. Electroencephalography findings did not correlate with neuropsychological performance, nor with the neuroradiologic findings. CONCLUSIONS: Late cerebral sequelae were frequently seen in patients treated on venoarterial ECMO. A significant correlation was found between cognitive impairment and neuroradiologic findings.

Development of an instrument to indirectly monitor arterial pCO2 during cardiopulmonary bypass.

Arterial blood carbon dioxide tension (PaCO2) during cardiopulmonary bypass (CBP) is important to the conduct of perfusion with alpha-stat or pH-stat strategy. Temperature changes during CBP complicate any attempts to monitor carbon dioxide tension in the exhaust outlet of an oxygenator (PexCO2) because CO2 becomes more soluble with decreasing temperatures. Normally, this would have been the obvious and easy choice of method to indirectly measure the patient's PaCO2. Several tests have been performed with ordinary capnographs modified to measure pCO2 at the oxygenator exhaust gas port. These tests have shown varying degrees of precision (Br I Anaesth 1999; 82(6): 843-46; 1 Extra-Corpor Technol 2003; 35(3): 218-23; Br JAnaesth 2000; 84: 536; J Extra-Corpor Technol 1994; 26: 64-67). Some of the best results have been achieved by Potger et al. (JExtra-Corpor Technol 2003; 35(3): 218-23), who found a strong correlation between the arterial temperature-corrected PexCO2 when using a standard capnograph monitoring the PaCO2 measured from a blood gas analyser (PbCO2). Our group has developed a new instrument, especially designed for oxygenator gas exhaust monitoring. The new instrument has automatic temperature correction, enabling it to show both original and corrected pCO2 values, simultaneously. Ordinary capnograph functions, such as zeroing, flow control and calibration routines, are included. The solution consists of a pCO2 sensor module, a temperature sensor, a water trap and a dedicated PC mounted on a heart-lung machine. Since the heart-lung machine was already equipped with a computer for data logging and a temperature sensor, only a box containing the pCO2 sensor module and the water trap had to be added. The PC uses a specially written program designed to collect data, make the necessary calculations and display the results on the computer screen. A temperature correction was developed based on a linear regression analysis for a data-set of 15 patients, assuming that the deviation between the measured PexCO2 from the oxygenator exhaust outlet and the PbCO2 from the blood gas analyser was linearly dependent on arterial temperature alone. Eighty-six blood gas samples were compared to the corrected PexCO2 values. The final product displayed good qualities of stability and was accurate when temperature fluctuated from 32 to 38 degrees C, even during rewarming, which has been reported to be a problem for other PexCO2 investigations (J Extra-Corpor Technol 2003; 35(3): 218-23).

Clinical evaluation of an instrument to measure carbon dioxide tension at the oxygenator gas outlet in cardiopulmonary bypass.

This paper presents the clinical testing of a new capnograph designed to measure the carbon dioxide tension at the oxygenator exhaust outlet in cardiopulmonary bypass (CPB). During CPB, there is a need for reliable, accurate and instant estimates of the arterial blood CO2 tension (PaCO2) in the patient. Currently, the standard practice for measuring PaCO2 involves the manual collection of intermittent blood samples, followed by a separate analysis performed by a blood gas analyser. Probes for inline blood gas measurement exist, but they are expensive and, thus, unsuitable for routine use. A well-known method is to measure PexCO2, ie, the partial pressure of CO2 in the exhaust gas output from the oxygenator and use this as an indirect estimate for PaCO2. Based on a commercially available CO2 sensor circuit board, a laminar flow capnograph was developed. A standard sample line with integrated water trap was connected to the oxygenator exhaust port. Fifty patients were divided into six different groups with respect to oxygenator type and temperature range. Both arterial and venous blood gas samples were drawn from the CPB circuit at various temperatures. Alfa-stat corrected pCO2 values were obtained by running a linear regression for each group based on the arterial temperature and then correcting the PexCO2 accordingly. The accuracy of the six groups was found to be (+/- SD): +/- 4.3, +/- 4.8, +/- 5.7, +/- 1.0, +/- 3.7 and +/- 2.1%. These results suggest that oxygenator exhaust capnography is a simple, inexpensive and reliable method of estimating the PaCO2 in both adult and pediatric patients at all relevant-temperatures.

[A 54-year old man with severe circulatory collapse]. / En 54 år gammel mann med alvorlig sirkulasjonssvikt.

The frequent use of mechanical circulatory assistive devices in the treatment of patients in cardiogenic shock increases the need for advanced air and ground transport services. In this article we describe a critically ill patient with acute myocardial infarction. He was treated with intraaortic balloon pump at the local hospital before transfer to a university hospital by air. Close cooperation between the university hospital, the Norwegian Air Ambulance and the Norwegian aviation authorities has facilitated this service.