National High Blood Pressure Education Program.

The catecholamine and cardiovascular responses to laryngoscopy alone have been compared with those following laryngoscopy and intubation in 24 patients allocated randomly to each group. Following induction with fentanyl and thio-pentone, atracurium was administered and artificial ventilation undertaken via a face mask for 2 min with 67% nitrous oxide in oxygen. Following laryngoscopy, the vocal cords were visualized for 10 s. In one group of patients, ventilation was then re-instituted via a face mask, while in the second group the trachea was intubated during the 10-s period and ventilation of the lungs maintained. Arterial pressure, heart rate and plasma noradrenaline and adrenaline concentrations were measured before and after induction and at 1, 3 and 5 min after laryngoscopy. There were significant and similar increases in arterial pressure and circulating catecholamine concentrations following laryngoscopy with or without intubation. Intubation, however, was associated with significant increases in heart rate which did not occur in the laryngoscopy-only group.

Cardiovascular and catecholamine responses to laryngoscopy with and without tracheal intubation

https://www.jpsmjournal.com/article/S0885-3924(04)00335-5/pdf

Opioids in renal failure and dialysis patients

Background
Patients may control postoperative pain by self-administration of intravenous opioids using devices designed for this purpose (patient controlled analgesia or PCA). A 1992 meta-analysis by Ballantyne found a strong patient preference for PCA over conventional analgesia but disclosed no differences in analgesic consumption or length of postoperative hospital stay. Although Ballantyne's meta-analysis found that PCA did have a small but statistically significant benefit upon pain intensity, Walder's review in 2001 did not find a significant differences in pain intensity and pain relief between PCA and conventionally treated groups.

Objectives
To evaluate the efficacy of PCA versus conventional analgesia (such as a nurse administering an analgesic upon a patient's request) for postoperative pain control.

Search methods
Randomized controlled trials (RCTs) were identified from the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2004, Issue 3), MEDLINE (1966 to 2004), and EMBASE (1994 to 2004). Additional reports were identified from the reference lists of retrieved papers.

Selection criteria
RCTs of PCA versus conventional analgesia that employed pain intensity as a primary or secondary outcome were selected. These trials included RCTs that compared PCA without a continuous background infusion versus conventional parenteral analgesic regimens. Studies that explicitly stated they involved patients with chronic pain were excluded.

Data collection and analysis
Trials were scored using the Oxford Quality Scale. Meta-analyses were performed of outcomes that included analgesic efficacy assessed by a Visual Analog Scale (VAS), analgesic consumption, patient satisfaction, length of stay and adverse effects. A sufficient number of the retrieved trials reported these parameters to permit meta-analyses.

Main results
Fifty-five studies with 2023 patients receiving PCA and 1838 patients assigned to a control group met inclusion criteria. PCA provided better pain control and greater patient satisfaction than conventional parenteral 'as-needed' analgesia. Patients using PCA consumed higher amounts of opioids than the controls and had a higher incidence of pruritus (itching) but had a similar incidence of other adverse effects. There was no difference in the length of hospital stay.

Authors' conclusions
This review provides evidence that PCA is an efficacious alternative to conventional systemic analgesia for postoperative pain control.

Patient controlled opioid analgesia versus conventional opioid analgesia for postoperative pain.

https://www.criticalcare.theclinics.com/article/S0749-0704(06)00046-7/pdf

Management of Intracranial Hypertension

Plasma adrenaline and noradrenaline concentrations were measured in 24 patients during the induction of anaesthesia and the subsequent tracheal intubation. The patients received either suxamethonium 1 mg kg−1 or pancuronium 0.1 mg kg−1 to facilitate tracheal intubation. Mean arterial pressure (MAP) increased in both groups following laryngoscopy and tracheal intubation and there were concomitant increases in the plasma catecholamine concentrations, the changes being more marked in the suxamethonium group. There was a significant correlation between MAP and plasma catecholamine concentrations in the suxamethonium group. Measurement of plasma catecholamine concentrations in samples obtained simultaneously from central venous, peripheral venous and arterial sites were in broad agreement; the greatest changes occurred in central venous samples.

Plasma catecholamine responses to tracheal intubation

Morphine 0.125 mg kg-1 was administered i.v. to 11 normal subjects and nine patients with chronic renal failure requiring regular haemodialysis. Plasma morphine concentrations were measured using high pressure liquid chromatography (HPLC). Although there was considerable individual variation in both groups, mean plasma concentrations of morphine were significantly higher in the patients with renal failure for 15 min after administration. The decay of plasma concentration fitted a three-compartment mamillary pharmacokinetic model in all subjects. Derived values (mean +/- SEM) of T 1/2 alpha, volume of distribution of the second compartment (V2), total volume of distribution at steady state (Vss) and transfer rate constant from the first to the second compartment (k12), were significantly different between groups. Mean values of terminal elimination half-life (T 1/2 gamma) and total body clearance were similar in the two groups. It was concluded that elimination of unchanged morphine is not impaired significantly in patients with chronic renal failure, although accumulation of morphine-3-glucuronide probably occurs. Although the pharmacological effect of morphine is not related temporally to plasma morphine concentrations, the higher values in patients with renal failure may be implicated in their increased sensitivity to the drug.

Pharmacokinetics of a Single-Dose IV Morphine in Normal Volunteers and Patients with End-Stage Renal Failure

Plasma Catecholamine Responses to Tracheal Intubation

The catecholamine and cardiovascular responses to intubation were investigated during halothane anaesthesia. Thirty patients were allocated randomly to two groups. Following induction of anaesthesia and muscle relaxation, group 1 was ventilated with 70% nitrous oxide in oxygen before intubation; group 2 received 1 % halothane in addition. After intubation, both groups received 0.5% halothane. Arterial pressure and heart rate, and plasma noradrenaline and adrenaline concentrations were measured throughout the induction sequence. In group 1 intubation was associated with increases {from pre-induction values) in systolic arterial pressure of 13% and diastolic arterial pressure of 35%, although the plasma concentrations of noradrenaline did not alter significantly. In group 2, although there was a pressor response to intubation, no overall change in systolic arterial pressure and only a 13% increase in diastolic arterial pressue occurred when compared with pre-induction values. This response was associated with a 78% increase in the noradrenaline concentration; the adrenaline concentration did not alter significantly.

K. Achola

Papers

Cardiovascular and catecholamine responses to laryngoscopy with and without tracheal intubation

Plasma catecholamine responses to tracheal intubation

Pharmacokinetics of a Single-Dose IV Morphine in Normal Volunteers and Patients with End-Stage Renal Failure

Plasma Catecholamine Responses to Tracheal Intubation

Effect of halothane on cardiovascular and plasma catecholamine responses to tracheal intubation