SummaryRegional anaesthesia is often helpful in improving respiratory function and analgesia following multiple rib fractures. The erector spinae plane block has become the technique of choice in our institution due to its relative simplicity and purported safety. The aim of this retrospective cohort study was to determine its effectiveness in improving respiratory and analgesic outcomes. We reviewed electronic medical records of patients with traumatic rib fractures admitted to a level‐one trauma centre between January 2016 and July 2017, who also received erector spinae plane blocks. We analysed the following outcomes before and up to 72 h after erector spinae plane blockade: incentive spirometry volume; maximum numerical rating scale static pain scores; and 12‐h opioid consumption. Pre‐ and post‐block data were compared. We included 79 patients, 77% of whom received continuous erector spinae plane block for a mean (SD) of 3.7 (1.9) days. The majority (85%) had other associated injuries. Incentive spirometry volumes improved from 784 (694) to 1375 (667) ml (p < 0.01) during the first 24 h following erector spinae plane blockade. Pain scores were reduced from 7.7 (2.5) to 4.7 (3.2) in the first three hours (p < 0.01). Reductions in opioid consumption were observed but did not achieve statistical significance. These improvements were largely sustained for up to 72 h. Mean arterial blood pressure remained unchanged from baseline. In conclusion, erector spinae plane blocks were associated with improved inspiratory capacity and analgesic outcomes following rib fracture, without haemodynamic instability. We propose that it should be considered to be a viable alternative to other regional analgesic techniques when these are not feasible.

To characterize the effects of pregnancy on vascular tissue, intact segments of the uterine and carotid arteries were removed from nonpregnant and near-term pregnant sheep. Pressure-diameter relations were measured on isolated segments under activated (122 mM K+, 10(-4) M phenylephrine) and passive (0.1 mM Ca2+, 10(-5) M iodoacetic acid) conditions. DNA and RNA were determined spectrophotometrically. Collagen, elastin, and water contents were also measured. Pregnancy had no effect on either the mechanics or the biochemical properties of the carotid artery. However, there was a marked increase in internal radius in the uterine artery with pregnancy (0.060 +/- 0.016 vs. 0.198 +/- 0.019 cm). Active tangential stress increased, as did passive stiffness of the uterine artery. The collagen fraction decreased during pregnancy (57.2 +/- 2.4 vs. 45.7 +/- 2.2%), while elastin and RNA remained unchanged. A small decrease in DNA produced a significant increase in the RNA-to-DNA ratio. These data suggest that, in pregnancy, the uterine artery selectively undergoes a characteristic hypertrophy of its vascular smooth muscle.

SUMMARYThe effect of chronic protein-calorie undernutrition (PCU) on cardiac structure, biochemistry, myocardial function, and left ventricular dynamics was studied in young, male, Long-Evans rats. Chronic PCU produced marked cachexia of the marasmic type (body weight decreased to 48% of normally nourished control rats) and cardiac atrophy (heart weight at 57% of control). Myocardial structure on light microscopy was normal and myocardial edema (dry/wet weight) was not present. An increased left ventricular DNA content (1.82 + 0.67 BE VS. 1.25 ± 0.58 pg/mg tissue wet weight) and collagen content (70.61 ± 4.54 vs. 31.72 ± 2.44 pg/mg, P< 0.001) in the presence of normal concentrations of RNA and actomyosin suggested a decrease in myofiber size with normal contractile proteins and protein synthesis. Resting length-tension curves for left ventricular papillary muscles failed to demonstrate alterations in myocardial stiffness with PCU. Active length-tension curves demonstrated enhanced myocardial contractility in chronic PCU hearts: peak developed isometric tension at U , was 4.84 ± 0.21 vs. 3.24 ± 0.31 g/mm*, P < 0.01. The in situ heart preparation in anesthetized PCU rats demonstrated bradycardia, hypotension, and a depressed cardiac output when compared to control hearts. However, cardiac output adjusted for body weight was normal (0.048 ± 0.005 vs. 0.044 ± 0.002 ml/min per g), and ventricular function curves, using stroke work index, showed a normal cardiac reserve in PCU rats. We conclude that uncomplicated chronic PCU is accompanied by cardiac atrophy, normal or enhanced myocardial contractility, and left ventricular function that has adjusted to the decrease in body mass and metabolic requirements. Ore Res 45:144-162, 1979

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