[An asymptomatic patient with lactate acidosis and hypercapnia]. / Een asymptomatische patiënt met lactaatacidose en hypercapnie.

BACKGROUND: Blood gas analyses are used to identify acid-base and respiratory disturbances. Blood gas abnormalities can be first signs of serious underlying disease. CASE DESCRIPTION: An 82-year old women with chronic kidney disease (eGFR 35 ml/min/1.73m2) and rheumatoid arthritis was admitted to the geriatric ward due to a urinary tract infection and bloody diarrhea. She repeatedly had a low oxygen saturation, although without symptoms. Capillary blood gas analysis was evidently disturbed (pH 6.96, pCO2 9.3 kPa, lactate 8.4 mmol/l), and led to consultation of the intensivist. Careful physical examination demonstrated that the patients' hands had blue discoloration, typical for Raynaud's phenomenon. Arterial blood gas demonstrated normal results. CONCLUSION: Capillary blood gas analysis is less reliable when peripheral circulation is disturbed. When the results are aberrant, it is important to distinguish between peripheral vascular disease and diminished systemic circulation. Arterial blood gas analysis can be used to support the diagnosis.

Preemptive dosage reduction of nadroparin in patients with renal failure: a retrospective case series.

BACKGROUND: Low-molecular-weight heparins (LMWHs) are frequently used to treat arterial and venous thrombo-embolic events. LMWHs accumulate with renal failure, but only limited clinical data regarding appropriate dosage adjustments are available. Nevertheless, LMWHs are routinely used in these patients worldwide. Although many clinics apply renal function-based dosage reductions, anti-factor Xa (anti-Xa) activity is not measured routinely. METHODS: We determined anti-Xa activity in 51 patients with MDRD-eGFR <60 mL/min/1.73 m(2), treated with therapeutic doses of nadroparin according to a standard, renal function-based guideline. RESULTS: An a priori dosage reduction resulted in anti-Xa activity within, below and above the reference range in 51, 30 and 19% of the measurements, respectively. Treatment resulted in different anti-Xa activities compared with dosages that were not given according to official advice (P < 0.001). Anti-Xa values increased with longer treatment duration (P = 0.038). CONCLUSIONS: A preemptive fixed reduction (25%) of the nadroparin dosage in all patients with renal failure seems appropriate. However, because target anti-Xa activities were reached in only half of the patients, we submit that the use of nadroparin, dosage reduction and monitoring of anti-Xa activity in combination with clinical outcome monitoring in this patient population urgently needs further investigation.