Correspondence
I87
Fig. 1. Laerdal open mask with supplementary oxygen supply and capnograph sampling tube
Fig. 2. Laerdal open mask attached to a patient.
cally and t o record the CO, waveform graphically. Any changes in the quality of ventilation will be detected immediately on a breath-to-breath bask4 The use of capnography in a spontaneously breathing patient is a more sensitive method of detection of early changes. Other variables are still within normal limits. We have used this technique for approximately one year (400 cases) and are able to recommend its effectiveness. Nahariya Government Hospital, Israel
R. FRANKELL T. KARRAM K. SIMON
References 1. KEATSAS. The effect of drugs on respiration in man. Annual Review of Pharmacology and Toxicology 1985; 25: 41-65. 2. CAPLAN RA, WARDRJ, POSNERK, CHENEY FW. Unexpected cardiac arrest during spinal anesthesia. A closed claims analysis of predisposing factors. Anesthesiology 1988; 68:5-1 I . 3. SULPICIO GS, RORYSJ. The use of pulse oxymetry to detect desaturation in patients receiving regional anesthesia with intravenous sedation. Regional Anesthesia 1989; 14 25-9. RA, WARDRJ, CHENEY FW. 4. TINKERJH, DULLDL, CAPLAN Role of monitoring devices in prevention of anesthetic mishaps. A closed claims analysis. Anesthesiology 1989; 71: 541-6.
Management of supraventricular tachycardia in septic patients Supraventricular tachycardia (SVT) may complicate the management of patients in septic shock. Many factors contribute to the evolution of SVT in septicaemia including fever, circulating endotoxin and peripheral vasodilatation. A standard treatment in uncomplicated SVT is verapamil.
Its actions on the conducting system are beneficial, but myocardial depression and vasodilatation may result in severe hypotension. We evaluated 19 postoperative patients with septicaemia and vasodilatation. Each patient developed SVT after sur-
788
Correspondence
gery for cancer and showed signs and symptoms of septicaemia including fever (38.4-39.OoC),leucocytosis tachycardia and hypotension (mean arterial pressure 2&30 mmHg less than before operation). When SVT started the blood pressure declined an additional I W O mmHg. The first group of nine patients were treated with verapamil alone. The second group consisted of 10 patients who were treated with phenylephrine and verapamik. Group I patients were given verapamil in increments of 2.5 mg every 5 minutes to a total dose of 10-15 mg. Verapamil precipitated an immediate decrease in blood pressure in all nine patients. Four patients converted to a sinus rhythm, three required cardioversion and digoxin, and two suffered cardiac arrest immediately after the verapamil-induced hypotension. The second group of(patients received phenylephrine and verapamil. Five patients responded to phenylephrine lo& 200 pg and verapamil.5 mg while the other four patients required phenylephrine 30&500 pg and verapamil 10 mg for conversion to a sinus rhythm.
The tachycardia in septic patients may be in response to vasodilatation, increased catecholamines, fever or endotoxins. Verapamil slows atrioventricular conduction, depresses the myocardium and causes peripheral vasodilatation. The effect on the conducting system is useful in the termination of SVT, but the myocardial depression and vasodilatation are undesirable side effects in hypotensive patients. Drugs which cause peripheral vasoconstriction, such as phenylephrine, are sometimes effective in slowing the heart reflexly and in conversion of SVT to a sinus rhythm. This study demonstrates that phenylephrine prevents hypotension and potentiates the therapeutic effect of verapamil in SVT.
University of Southern California School of Medicine, Los Angeles. California 90033, USA
H.F. BOWLES D. THANCATHURAI G.E. MORGAN M . MIKHAIL
Trauma to epidural veins: the role of posture
The sequelae of damage to the epidural venous plexus during the insertion of a lumbar epidural catheter can, at best, be an inconvenience, and require reinsertion at a different site, or at worst a major catastrophe with the formation of a spinal haematoma. Commonsense and a knowledge of anatomy leads one to conclude that this valveless plexus becomes engorged when a patient moves from the lateral to the sitting position. One would further assume that this would make damage to these vessels during the insertion of an epidural catheter more likely. A simple two-part study was conceived to test this hypothesis. Firstly, the records of 1060 obstetric epidurals inserted by six anaesthetist colleagues were studied. Three of these anaesthetists inserted all of their epidurals with the patient in the sitting position, and the other three with the patient in the lateral position. The incidence of epidural vein trauma (defined as either blood freely aspirated through Tuohy needle or free back flow along the catheter) was 6.8% in the sitting group (573 patients) and 5.3% in the lateral group (487 patients). This difference was not significant. Secondly, 1 studied my own clinical practice. Two hundred and nineteen consecutive obstetric epidurals were inserted with the patient in the sitting position and the next 86 with the patient in the lateral position. The incidence of epidural vein trauma (as defined earlier) of the first 20 insertions in each patient position were compared with the subsequent insertions in that position and secondly, the overall incidence in the sitting versus lateral positions. The results are given in Table 1. The incidence of vein trauma was significantly higher during the first 20 insertions in both positions when com-
Table 1. Incidence of bleeding in relation to position of the patient. -
~
Number bleeding
~~
Overall
Yn
First 20 sitting
5
25**
Next 199 sitting
10
5**
First 20 lateral
5
25*
Next 66 lateral
4
6*
%
6.8 10.5
**p < 0.01; *p < 0.05.
pared with the subsequent insertions. However, there was no significant difference in the overall incidence between sitting and lateral positions. There appears to be no difference in the incidence of trauma to the epidural vein with the patient in the sitting or in the lateral position. However, a change in operator technique from one position to the other does appear to increase the incidence. This is presumably because a temporary difficulty in locating familiar landmarks led to the needle straying towards the epidural veins in the lateral parts of the space. It seems prudent advice therefore, to recommend the establishment of one’s own technique and, where possible, to stick to it.
Royal Liverpool Hospital, PO Box 147, Liverpool L6Y 3BX
E.S. SHEARER
Convulsions after cocaine and propofol Most of the reported incidents of opisthotonus and grand ma1 convulsions associated with propofol have involved either a history of investigation for epilepsy, a family history of epilepsy or diagnosed epilepsy.’-4 All of the reactions in patients without any epileptic history included the use of intravenous alfentanil,’-’ with the exception of one patient.’ The reactions seen in the first group begin with an opisthotonic posture and lead to repeated grand
ma1 convulsions. The second group exhibit an opisthotonic posture that may proceed to one episode of convulsions. This report is about a case of convulsions after the use of propofol, which was neither associated with the use of alfentanil nor a history of investigation for epilepsy nor a familial tendency towards epilepsy. A fit 23-year-old male presented for a septorhinoplasty for cosmetic reasons. There was no history of head injury. He had no significant
I87
Fig. 1. Laerdal open mask with supplementary oxygen supply and capnograph sampling tube
Fig. 2. Laerdal open mask attached to a patient.
cally and t o record the CO, waveform graphically. Any changes in the quality of ventilation will be detected immediately on a breath-to-breath bask4 The use of capnography in a spontaneously breathing patient is a more sensitive method of detection of early changes. Other variables are still within normal limits. We have used this technique for approximately one year (400 cases) and are able to recommend its effectiveness. Nahariya Government Hospital, Israel
R. FRANKELL T. KARRAM K. SIMON
References 1. KEATSAS. The effect of drugs on respiration in man. Annual Review of Pharmacology and Toxicology 1985; 25: 41-65. 2. CAPLAN RA, WARDRJ, POSNERK, CHENEY FW. Unexpected cardiac arrest during spinal anesthesia. A closed claims analysis of predisposing factors. Anesthesiology 1988; 68:5-1 I . 3. SULPICIO GS, RORYSJ. The use of pulse oxymetry to detect desaturation in patients receiving regional anesthesia with intravenous sedation. Regional Anesthesia 1989; 14 25-9. RA, WARDRJ, CHENEY FW. 4. TINKERJH, DULLDL, CAPLAN Role of monitoring devices in prevention of anesthetic mishaps. A closed claims analysis. Anesthesiology 1989; 71: 541-6.
Management of supraventricular tachycardia in septic patients Supraventricular tachycardia (SVT) may complicate the management of patients in septic shock. Many factors contribute to the evolution of SVT in septicaemia including fever, circulating endotoxin and peripheral vasodilatation. A standard treatment in uncomplicated SVT is verapamil.
Its actions on the conducting system are beneficial, but myocardial depression and vasodilatation may result in severe hypotension. We evaluated 19 postoperative patients with septicaemia and vasodilatation. Each patient developed SVT after sur-
788
Correspondence
gery for cancer and showed signs and symptoms of septicaemia including fever (38.4-39.OoC),leucocytosis tachycardia and hypotension (mean arterial pressure 2&30 mmHg less than before operation). When SVT started the blood pressure declined an additional I W O mmHg. The first group of nine patients were treated with verapamil alone. The second group consisted of 10 patients who were treated with phenylephrine and verapamik. Group I patients were given verapamil in increments of 2.5 mg every 5 minutes to a total dose of 10-15 mg. Verapamil precipitated an immediate decrease in blood pressure in all nine patients. Four patients converted to a sinus rhythm, three required cardioversion and digoxin, and two suffered cardiac arrest immediately after the verapamil-induced hypotension. The second group of(patients received phenylephrine and verapamil. Five patients responded to phenylephrine lo& 200 pg and verapamil.5 mg while the other four patients required phenylephrine 30&500 pg and verapamil 10 mg for conversion to a sinus rhythm.
The tachycardia in septic patients may be in response to vasodilatation, increased catecholamines, fever or endotoxins. Verapamil slows atrioventricular conduction, depresses the myocardium and causes peripheral vasodilatation. The effect on the conducting system is useful in the termination of SVT, but the myocardial depression and vasodilatation are undesirable side effects in hypotensive patients. Drugs which cause peripheral vasoconstriction, such as phenylephrine, are sometimes effective in slowing the heart reflexly and in conversion of SVT to a sinus rhythm. This study demonstrates that phenylephrine prevents hypotension and potentiates the therapeutic effect of verapamil in SVT.
University of Southern California School of Medicine, Los Angeles. California 90033, USA
H.F. BOWLES D. THANCATHURAI G.E. MORGAN M . MIKHAIL
Trauma to epidural veins: the role of posture
The sequelae of damage to the epidural venous plexus during the insertion of a lumbar epidural catheter can, at best, be an inconvenience, and require reinsertion at a different site, or at worst a major catastrophe with the formation of a spinal haematoma. Commonsense and a knowledge of anatomy leads one to conclude that this valveless plexus becomes engorged when a patient moves from the lateral to the sitting position. One would further assume that this would make damage to these vessels during the insertion of an epidural catheter more likely. A simple two-part study was conceived to test this hypothesis. Firstly, the records of 1060 obstetric epidurals inserted by six anaesthetist colleagues were studied. Three of these anaesthetists inserted all of their epidurals with the patient in the sitting position, and the other three with the patient in the lateral position. The incidence of epidural vein trauma (defined as either blood freely aspirated through Tuohy needle or free back flow along the catheter) was 6.8% in the sitting group (573 patients) and 5.3% in the lateral group (487 patients). This difference was not significant. Secondly, 1 studied my own clinical practice. Two hundred and nineteen consecutive obstetric epidurals were inserted with the patient in the sitting position and the next 86 with the patient in the lateral position. The incidence of epidural vein trauma (as defined earlier) of the first 20 insertions in each patient position were compared with the subsequent insertions in that position and secondly, the overall incidence in the sitting versus lateral positions. The results are given in Table 1. The incidence of vein trauma was significantly higher during the first 20 insertions in both positions when com-
Table 1. Incidence of bleeding in relation to position of the patient. -
~
Number bleeding
~~
Overall
Yn
First 20 sitting
5
25**
Next 199 sitting
10
5**
First 20 lateral
5
25*
Next 66 lateral
4
6*
%
6.8 10.5
**p < 0.01; *p < 0.05.
pared with the subsequent insertions. However, there was no significant difference in the overall incidence between sitting and lateral positions. There appears to be no difference in the incidence of trauma to the epidural vein with the patient in the sitting or in the lateral position. However, a change in operator technique from one position to the other does appear to increase the incidence. This is presumably because a temporary difficulty in locating familiar landmarks led to the needle straying towards the epidural veins in the lateral parts of the space. It seems prudent advice therefore, to recommend the establishment of one’s own technique and, where possible, to stick to it.
Royal Liverpool Hospital, PO Box 147, Liverpool L6Y 3BX
E.S. SHEARER
Convulsions after cocaine and propofol Most of the reported incidents of opisthotonus and grand ma1 convulsions associated with propofol have involved either a history of investigation for epilepsy, a family history of epilepsy or diagnosed epilepsy.’-4 All of the reactions in patients without any epileptic history included the use of intravenous alfentanil,’-’ with the exception of one patient.’ The reactions seen in the first group begin with an opisthotonic posture and lead to repeated grand
ma1 convulsions. The second group exhibit an opisthotonic posture that may proceed to one episode of convulsions. This report is about a case of convulsions after the use of propofol, which was neither associated with the use of alfentanil nor a history of investigation for epilepsy nor a familial tendency towards epilepsy. A fit 23-year-old male presented for a septorhinoplasty for cosmetic reasons. There was no history of head injury. He had no significant
