Case Report: Using ultrasound to prevent a broken catheter from migrating to the heart.

Peripheral intravenous (IV) catheters can break off while still in the patient, with possible detrimental effects such as upstream migration to the heart. These catheters have probably been damaged by the needle during a difficult insertion. A peripheral IV catheter was removed in a 90 year old patient and only half of the catheter was retrieved. By using ultrasound examination the remaining part of the IV catheter was identified, and retrieved surgically, before it could migrate towards the heart. This case report suggests that ultrasound should not only be used for difficult placement of a peripheral IV catheter, but can also be used when removal is complicated

Laboratory Tests: Blood Gases, Anion Gap, and Strong Ion Gap

Blood gas measurements provide the intensivist with diagnostic information on many organ systems. The anion gap (AG) and the strong ion gap (SIG) exploit the principle of electroneutrality to quantify the net balance of unmeasured ions in plasma. The AG should be corrected for abnormalities in plasma albumin and phosphate concentrations. The AG and SIG can be used to narrow the differential diagnosis of acid-base disorders, and an increased corrected AG or SIG is diagnostic of a metabolic acidosis (i.e., an acidifying process) irrespective of plasma pH or bicarbonate. The SIG is often perceived as more complex but frequently yields more precise results in critically ill patients. In addition, the strong ion model can be used to guide fluid management because it acknowledges that electrolyte changes are causal mechanisms of acid-base disorders

Pulse-contour derived cardiac output measurements in morbid obesity: influence of actual, ideal and adjusted bodyweight

The non-invasive Nexfin cardiac output (CO) monitor shows a low level of agreement with the gold standard thermodilution method in morbidly obese patients. Here we investigate whether this disagreement is related to excessive bodyweight, and can be improved when bodyweight derivatives are used instead. We performed offline analyses of cardiac output recordings of patient data previously used and partly published in an earlier study by our group. In 30 morbidly obese patients (BMI > 35 kg/m2) undergoing laparoscopic gastric bypass, cardiac output was simultaneously determined with PiCCO thermodilution and Nexfin pulse-contour method. We investigated if agreement of Nexfin-derived CO with thermodilution CO improved when ideal and adjusted—instead of actual- bodyweight were used as input to the Nexfin. Bodyweight correlated with the difference between Nexfin-derived and thermodilution-derived CO (r = −0.56; p = 0.001). Bland Altman analysis of agreement between Nexfin and thermodilution-derived CO revealed a bias of 0.4 ± 1.6 with limits of agreement (LOA) from −2.6 to 3.5 L min when actual bodyweight was used. Bias was −0.6 ± 1.4 and LOA ranged from −3.4 to 2.3 L min when ideal bodyweight was used. With adjusted bodyweight, bias improved to 0.04 ± 1.4 with LOA from −2.8 to 2.9 L min. Our study shows that agreement of the Nexfin-derived with invasive CO measurements in morbidly obese patients is influenced by body weight, suggesting that Nexfin CO measurements in patients with a BMI above 35 kg/m2 should be interpreted with caution. Using adjusted body weight in the Nexfin CO-trek algorithm reduced the bias